Multilayer optical film

Multilayer optical film that can be used as a reflective polarizer or mirror is disclosed. The multilayer optical film comprises alternating optical layers of polyesters such as PET and PEN, copolymerized with 4,4'-biphenyl dicarboxylate. The multilayer optical film exhibits a high ratio of in-plane to out-of-plane birefringence.

Respirator Having Optically Active Exhalation Valve

Various embodiments of a respirator () that includes a harness (), a mask body (), and an exhalation valve () are disclosed. The exhalation valve () can include a valve seat () and a flexible flap () that is in engagement with the valve seat. The flexible flap can have one or more materials that can cause the flap to flash () when moving from a closed position to an open position or vice versa. The flashing valve can make it easier for a user to ascertain whether the valve is operating properly. 1. A respirator that comprises:a harness;a mask body; and a valve seat; and', 'a flexible flap that is in engagement with the valve seat, the flexible flap comprising one or more materials that cause the flap to flash when moving from a closed position to an open position or vice versa., 'an exhalation valve that comprises2. The respirator of claim 1 , wherein the exhalation valve further comprises a valve cover that is sufficiently transparent to enable the flashing to be seen through a solid portion of the valve cover.3. The respirator of claim 1 , wherein the flexible flap exhibits band shifting.4. The respirator of claim 1 , wherein the flexible flap comprises a specularly reflecting film.5. The respirator of claim 1 , wherein the flexible flap has indicia thereon created by altering the specular reflection of the flexible flap at selected areas without distorting or warping the flexible flap.6. The respirator of claim 1 , wherein the flexible flap comprises a band shifting film.7. The respirator of claim 6 , wherein the band shifting film is attached to an outer surface of the flexible flap.8. The respirator of claim 6 , wherein the band shifting film comprises a multilayer polymeric film.9. The respirator of claim 8 , wherein the multilayer polymeric film comprises a colored mirror.10. The respirator of claim 8 , wherein the multilayer polymeric film comprises a polarizer.11. The respirator of claim 1 , wherein the flexible flap comprises a diffusely reflective optical ...

LIGHT SOURCE INCORPORATING MULTILAYER OPTICAL FILM

A light source includes a lightguide having a top side comprising an optical film, a bottom side comprising a diffuse reflector, and an input side extending between the top and bottom sides. An illumination source is disposed proximate the input side of the lightguide. The optical film has adjacent first and second zones, each zone extending substantially an entire thickness of the optical stack or an entire thickness of at least one optical packet of the optical film. Light enters the lightguide from the light source propagating within the lightguide and being either reflected or transmitted by the optical film primarily by optical interference. For at least one first incidence angle and at least one wavelength, the first and second zones of the optical film have substantially equal optical transmittance. For at least one second incidence angle and at least one wavelength, the second zone has substantially greater optical transmittance than the first zone of the optical film. 110-. (canceled)11. A light source comprising:a substantially monochromatic illumination device emitting light at a first wavelength;an input side proximate the illumination device for receiving light at the first wavelength from the illumination device;a bottom side comprising a diffuse reflector; anda top side comprising an optical film having a plurality of layers, each layer extending adjacent first and second zones of the optical film and transmitting and reflecting light in the at least the first zone primarily by optical interference, at least one layer in the plurality of layers having different birefringence in the first and second zones so that for light at the first wavelength incident at a first incidence angle, each of the first and second zones of the optical film has a substantially greater optical transmittance than reflectance, and for light at the first wavelength incident at a greater second incidence angle, the first zone of the optical film has a substantially smaller ...

Stabilized infrared absorbing dispersions

A dispersion, a resin containing the dispersion and polymer film formed from the resin are disclosed. The dispersion includes an infrared light absorbing pigment including organo-metallic particles being less than 1.5 micrometer or less than one micrometer in size. The dispersion also includes a dispersant including phosphorus and a polyol.

Inconspicuous optical tags and methods therefor

Tags are made from optical films to provide a pattern that is inconspicuous to ordinary observers, but that is detectable by a camera or other imaging device. The pattern is provided by first and second portions of a patterned layer, the first portions selectively filtering at least a portion of blue visible light from other visible light wavelengths. Filtering in the portion of the blue region helps make the pattern inconspicuous. The tags may also include an indicia layer configured to mark a location of the pattern, and a contrast enhancing layer disposed behind the patterned layer and configured to enhance a contrast of the pattern. In some cases, the first portions of the patterned layer may filter optical wavelengths other than blue, such as near-infrared light. The pattern may comprise machine-readable information, e.g., a linear bar code or a 2-D bar code. Associated methods and systems are also disclosed.

Multilayer optical film

Multilayer optical film that can be used as a reflective polarizer or mirror is disclosed. The multilayer optical film comprises alternating optical layers of polyesters such as PET and PEN, copolymerized with 4,4′-biphenyl dicarboxylate. The multilayer optical film exhibits a high ratio of in-plane to out-of-plane birefringence.

CONDUCTIVE POLYMERIC MATERIAL

A melt-processable conductive material including a first continuous phase, a second continuous phase and a non-continuous phase. The first continuous phase includes a first polymer, the second continuous phase includes a second polymer, and the non-continuous phase includes a third polymer. The second continuous phase is co-continuous with the first continuous phase and the non-continuous phase is substantially contained within the first continuous phase. A plurality of conductive particles is distributed in the first polymer or at a boundary between the first continuous phase and the second continuous phase. The conductive particles form a conductive network. 1. A conductive material , comprising:a first continuous phase comprising a first polymer;a second continuous phase comprising a second polymer different from the first polymer, the second continuous phase co-continuous with the first continuous phase;a non-continuous phase comprising a third polymer different from the first polymer and different from the second polymer, the non-continuous phase substantially contained within the first continuous phase; anda plurality of conductive particles distributed in the first polymer or at a boundary between the first continuous phase and the second continuous phase,wherein the conductive particles form a conductive network and wherein the conductive material is melt-processable.2. The conductive material of claim 1 , wherein the conductive particles are distributed in the first polymer.3. The conductive material of claim 1 , wherein the conductive particles are distributed at the boundary between the first continuous phase and the second continuous phase.4. The conductive material of claim 1 , wherein the second polymer is a silicone-based polymer.5. The conductive material of claim 1 , wherein the conductive particles are spherical particles claim 1 , rod-shaped particles claim 1 , flakes claim 1 , platelets or a combination thereof.6. The conductive material of claim ...

Effective media retarder films with spatially selective birefringence reduction

A retarder film provides a first light retardation and can be heat processed in one or more selected areas to provide a second light retardation in the selected area(s). The retarder film may have an absorption characteristic such that the heat processing can be carried out by selectively exposing the film to a suitable radiant beam. The retarder film is composed of a stack of contiguous ultrathin layers configured to provide an effective optical medium for visible light. Visible light propagates through the stack as an effective medium having effective refractive indices along principal x-, y-, and z-axes. At least some of the ultrathin layers possess intrinsic birefringence, and the effective indices of the stack are functions of the intrinsic refractive indices of the constituent ultrathin layers. The heat processing is carried out so that the ultrathin layer stack structural integrity is not substantially altered in the processed area(s).

FRONT PROJECTION SCREEN WITH HIGH CONTRAST

A light diffusing optical construction is disclosed. The optical construction includes an asymmetric optical diffuser that scatters light in a first direction with a first viewing angle Aand in a second direction orthogonal to the first direction with a second viewing angle A. The ratio A/Ais at least about 2. The optical construction also includes a substantially specular reflector that reflects light that is not scattered by the asymmetric optical diffuser. The substantially specular reflector has a first average reflectance Rin the visible at a substantially zero incident angle and a second average reflectance R45 in the visible at a substantially 45 degree incident angle. The ratio R/Ris at least about 1.5. The optical construction also includes a light absorbing layer that absorbs light that is not reflected by the specular reflector. 1. A light diffusing optical construction comprising:{'sub': H', 'V', 'H', 'V, 'an asymmetric optical diffuser scattering light in a first direction with a first viewing angle A, and in a second direction orthogonal to the first direction with a second viewing angle A, A/Abeing at least about 2;'}{'sub': o', '45', 'o', '45, 'a substantially specular reflector reflecting light that is not scattered by the asymmetric optical diffuser and having a first average reflectance Rin the visible at a substantially zero incident angle and a second average reflectance Rin the visible at a substantially 45 degree incident angle, R/Rbeing at least about 1.5; and'}a light absorbing layer absorbing light that is not reflected by the specular reflector.27-. (canceled)8. The light diffusing optical construction of claim 1 , wherein the asymmetric optical diffuser comprises a plurality of elongated structures within a first material claim 1 , the elongated structures being generally oriented along the second direction.9. (canceled)10. The front projection screen of claim 1 , wherein gain curves of the asymmetric optical diffuser for two mutually ...

Negatively birefringent polyesters and optical films

Presently described are multilayer optical films, oriented polyester films, negatively birefringent copolyester polymers, fluorene monomers, and polyester polymers prepared from such fluorene monomers. In one embodiment, the multilayer optical film comprises at least one first birefringent optical layer; and at least one second optical layer having a lower birefringence than the first optical layer; wherein at least one of the optical layers comprises a negatively birefringent polyester polymer comprising a backbone and repeat units comprising at least one pendent aromatic group that is conformationally locked relative to the backbone.

FRONT PROJECTION SCREEN WITH HIGH CONTRAST

A light diffusing optical construction is disclosed. The optical construction includes a symmetric optical diffuser that scatters light in a first direction with a first viewing angle Aand in a second direction orthogonal to the first direction with a second viewing angle A, where Ais substantially equal to A. The symmetric optical diffuser includes an optically transparent first layer and a plurality of randomly arranged optically transparent beads partially embedded in the first layer leaving portions of the beads exposed. The optical construction also includes a specular reflector that reflects light that is not scattered by the symmetric optical diffuser. The specular reflector has a first average reflectance Rin the visible at zero incident angle and a second average reflectance Rin the visible at 60 degree incident angle. R/Ris at least about 1.5. The optical construction also includes a light absorbing layer that absorbs light that is not reflected by the specular reflector. 19-. (canceled)10. A light diffusing optical construction comprising:{'sub': H', 'V', 'H, 'claim-text': a substantially optically transparent first layer; and', 'a plurality of substantially randomly arranged optically transparent beads partially embedded in the first layer;, 'a symmetric optical diffuser scattering light in a first direction with a first viewing angle Aand in a second direction orthogonal to the first direction with a second viewing angle Asubstantially equal to A, the symmetric optical diffuser comprising{'sub': o', '60', 'o', '60, 'a substantially specular reflector reflecting light that is not scattered by the symmetric optical diffuser and having a first average reflectance Rin the visible at a substantially zero incident angle and a second average reflectance Rin the visible at a substantially 60 degree incident angle, R/Rbeing at least about 1.5; and'}a light absorbing layer absorbing light that is not reflected by the specular reflector.11. The light diffusing ...

Optical stack having birefringent layer of optically symmetrical crystallites

An optical stack ( 400 ) having a plurality of alternating polymeric layers ( 401, 402 ) is described. The alternating layers may be alternating birefringent (syndiotactic polystyrene, sPS) and isotropic (CoPENa) layers, or alternating positively and negatively birefringent layers. Birefringent layers are made using polymers which form optically symmetrical crystallites upon stretching of the polymer. The optical stack has a large refractive index difference in the x-direction (the stretching direction) and small refractive index differences in the y- and z-directions (the non-stretching directions). The optical stack can be made using standard film tentering methods and may be a multilayer reflective polarizer.

MULTILAYER OPTICAL FILM

Multilayer optical film that can be used as a reflective polarizer or mirror is disclosed. The multilayer optical film comprises alternating optical layers of polyesters such as PET and PEN, copolymerized with 4,4′-biphenyl dicarboxylate. The multilayer optical film exhibits a high ratio of in-plane to out-of-plane birefringence. 1. A multilayer optical film comprising:alternating first and second optical layers,the first optical layer comprising a first polyester derived from first carboxylate monomers and first diol monomers, the first carboxylate monomers comprising from about 5 to about 50 mol % of 4,4′-biphenyl dicarboxylate,wherein the first and second optical layers have refractive indices along at least one axis that differ by at least 0.04.2. The multilayer optical film of claim 1 ,wherein 4,4′-biphenyl dicarboxylate is present in an amount of from about 20 to about 45 mol %, and the first carboxylate monomers further comprise terephthalate.3. The multilayer optical film of claim 2 ,wherein the first carboxylate monomers consist essentially of 4,4′-biphenyl dicarboxylate and terephthalate.4. The multilayer optical film of claim 1 ,wherein the first carboxylate monomers further comprise a dicarboxylate monomer having pendant ionic groups.5. The multilayer optical film of claim 4 ,wherein the dicarboxylate monomer having pendant ionic groups is present in an amount of less than about 5 mol % relative to the total moles of first carboxylate monomers.6. The multilayer optical film of claim 1 ,wherein the first dicarboxylate monomers further comprise terephthalate and dimethyl sulfoisophthalate.7. The multilayer optical film of claim 6 ,wherein the first dicarboxylate monomers consist essentially of 4,4′-biphenyl dicarboxylate, terephthalate, and dimethyl sulfoisophthalate.8. The multilayer optical film of claim 1 ,wherein 4,4′-biphenyl dicarboxylate is present in an amount of from about 4 to about 37 mol %, and the first carboxylate monomers further comprise ...

Effective Media Retarder Films with Spatially Selective Birefringence Reduction

A retarder film provides a first light retardation and can be heat processed in one or more selected areas to provide a second light retardation in the selected area(s). The retarder film may have an absorption characteristic such that the heat processing can be carried out by selectively exposing the film to a suitable radiant beam. The retarder film is composed of a stack of contiguous ultrathin layers configured to provide an effective optical medium for visible light. Visible light propagates through the stack as an effective medium having effective refractive indices along principal x-, y-, and z-axes. At least some of the ultrathin layers possess intrinsic birefringence, and the effective indices of the stack are functions of the intrinsic refractive indices of the constituent ultrathin layers. The heat processing is carried out so that the ultrathin layer stack structural integrity is not substantially altered in the processed area(s). 1. An optical article , comprising:a retarder film providing a first light retardation and comprising an effective medium stack of contiguous ultrathin layers configured to provide an effective optical medium for visible light, the ultrathin layers arranged into a plurality of optical repeat units each of which has an optical thickness of less than 190 nm, the ultrathin layers including different first and second ultrathin layers, the first ultrathin layers comprising a first polymer material exhibiting a first intrinsic birefringence, and the second ultrathin layers comprising a second polymer material;wherein the retarder film has a first absorption characteristic suitable to, upon exposure to a first radiant beam, absorptively heat the effective medium stack by an amount sufficient to change the first light retardation to a second light retardation, different from the first light retardation, while maintaining a structural integrity of the effective medium stack.2. The article of claim 1 , wherein the stack of contiguous ...

EXTRUDABLE URETHANE RELEASE COATING

Described herein is a release material comprising: a blend comprising: releasing agent comprising a urethane polymer derived from a polyvinyl polymer containing active hydroxyl groups and an aliphatic isocyanate; and a carrier polymer, wherein more than 50% by weight of the carrier polymer is non-olefinic, and articles thereof.

SPECTRALLY SELECTIVE LIGHT CONTROL FILM

A light control film is disclosed that includes a plurality of spaced apart first regions. Each first region has a substantially low transmission in one or two of a first wavelength range from about 300 nm to about 400 nm, a second wavelength range from about 400 nm to about 700 nm, and a third wavelength range from about 700 nm to about 1200 nm, and a substantially high transmission in the remaining wavelength ranges. The light control film has a viewing angle of less than about 70 degrees along a predetermined first direction. 1. A light control film comprising a plurality of spaced apart first regions and a second region , each first region having a width W and a height H , H/W≥1 , each first region having a substantially high transmission in a predetermined first wavelength range and a substantially low transmission in a predetermined non-overlapping second wavelength range , the second region having substantially high transmission in each of the predetermined first and second wavelength ranges.2. The light control film of comprising a major microstructured first surface having a plurality of alternating ribs and channels claim 1 , each channel at least partially filled with a first material to form one of the first regions in the plurality of spaced apart first regions.3. The light control film of claim 2 , wherein the second region comprises a plurality of second region segments claim 2 , each rib comprising one of the second region segments.4. The light control film of claim 1 , wherein the second region is disposed on a major surface of the light control film.5. The light control film of claim 1 , wherein the second region extends across and covers at least some of the first regions.6. The light control film of claim 1 , wherein the first wavelength range is about 400 nm to about 700 nm.7. The light control film of claim 1 , wherein the first wavelength range is about 400 nm to about 460 nm.8. The light control film of claim 1 , wherein the first wavelength ...

Multilayer film capacitor

A multilayer film capacitor having a composite stack disposed between two electrodes where the composite stack includes at least one thermoplastic conductive layer and at least one thermoplastic insulating layer. The total thickness of the conductive layers is at least 3 times the total thickness of the insulating layers. The conductive layers may include a thermoplastic polymer blended with conductive particles at a concentration higher than a percolation threshold.

STABILIZED INFRARED ABSORBING DISPERSIONS

A dispersion, a resin containing the dispersion and polymer film formed from the resin are disclosed. The dispersion includes an infrared light absorbing pigment including organo-metallic particles being less than 1.5 micrometer or less than one micrometer in size. The dispersion also includes a dispersant including phosphorus and a polyol. 1. A dispersion comprising:{'b': 1', '5, 'an infrared light absorbing pigment comprising organo-metallic particles, the infrared light absorbing pigment absorbs at a selected wavelength in a range of 750-1100 nm at least 1.5 times as strongly as in a visible range of 500-560 nm, at least 99% of the organo-metallic particles are less than . micrometer in size;'}a dispersant comprising phosphorus; anda polyol.2. The dispersion according to claim 1 , wherein the organo-metallic particles comprise Ti claim 1 , V claim 1 , Cr claim 1 , Mn claim 1 , Fe claim 1 , Co claim 1 , Ni claim 1 , Cu claim 1 , Zn claim 1 , Zr claim 1 , Nb claim 1 , Pd claim 1 , Ag claim 1 , Cd claim 1 , Ta claim 1 , W claim 1 , Pt claim 1 , or Au.3. The dispersion according to claim 1 , wherein the polyol is ethylene glycol.4. The dispersion according to claim 1 , wherein dispersant comprising phosphorus is soluble in the polyol at a weight % ratio of at least 1:100.5. The dispersion according to claim 1 , wherein at least 99% of the organo-metallic particles have a size in a range from 100 nm to 1000 nm.6. The dispersion according to claim 1 , wherein the organo-metallic particles comprise copper.7. The dispersion according to claim 1 , wherein the infrared light absorbing pigment comprises phthalocyanine moieties.8. The dispersion according to claim 1 , wherein the dispersion comprises at least 5 wt % infrared light absorbing pigment.9. The dispersion according to claim 1 , wherein the dispersant has a decomposition temperature of 280 degrees centigrade or less.10. A resin comprising:a polyester material;an infrared light absorbing pigment dispersed in the ...

STABILIZED INFRARED ABSORBING DISPERSIONS

A dispersion, a resin containing the dispersion and polymer film formed from the resin are disclosed. The dispersion includes an infrared light absorbing pigment including organo-metallic particles being less than 1.5 micrometer or less than one micrometer in size. The dispersion also includes a dispersant including phosphorus and a polyol. 1. A dispersion comprising:an infrared light absorbing pigment comprising organo-metallic particles, the infrared light absorbing pigment absorbs at a selected wavelength in a range of 750-1100 nm at least 1.5 times as strongly as in a visible range of 500-560 nm, at least 99% of the organo-metallic particles are less than 1.5 micrometer in size;a dispersant comprising phosphorus; anda polyol.2. The dispersion according to claim 1 , wherein the organo-metallic particles comprise Ti claim 1 , V claim 1 , Cr claim 1 , Mn claim 1 , Fe claim 1 , Co claim 1 , Ni claim 1 , Cu claim 1 , Zn claim 1 , Zr claim 1 , Nb claim 1 , Pd claim 1 , Ag claim 1 , Cd claim 1 , Ta claim 1 , W claim 1 , Pt claim 1 , or Au.3. The dispersion according to claim 1 , wherein the polyol is ethylene glycol.4. The dispersion according to claim 1 , wherein dispersant comprising phosphorus is soluble in the polyol at a weight % ratio of at least 1:100.5. The dispersion according to claim 1 , wherein at least 99% of the organo-metallic particles have a size in a range from 100 nm to 1000 nm.6. The dispersion according to claim 1 , wherein the organo-metallic particles comprise copper.7. The dispersion according to claim 1 , wherein the infrared light absorbing pigment comprises phthalocyanine moieties.8. The dispersion according to claim 1 , wherein the dispersion comprises at least 5 wt % infrared light absorbing pigment.9. The dispersion according to claim 1 , wherein the dispersant has a decomposition temperature of 280 degrees centigrade or less.10. A resin comprising:a polyester material;an infrared light absorbing pigment dispersed in the polyester material ...

OPTICAL CAMOUFLAGE FILTERS

An article includes an optical filter that comprises a wavelength selective reflective layer and at least one wavelength selective absorbing layer. The optical filter has visible transmittance between 400 nm-700 nm of less than about 30% and near infrared transmittance at 830 nm-900 nm greater than about 30%. 1. A printed article having an average transmittance of less than 0.1% for wavelengths between 400 nm and 700 nm and average transmittance of greater than 50% for wavelengths between 830 nm and 900 nm , the printed article comprising:a wavelength selective reflective layer comprising an interference filter having an average transmittance of greater than 50% for wavelengths between 830 nm and 900 nm and a transmittance of greater than 70% for wavelengths between 950 nm and 1250 nm, a transmission spectrum of the reflective layer comprising at least one peak between 400 nm and 700 nm; andat least one printed wavelength selective absorbing layer having an average visible transmittance for wavelengths between 400 nm and 700 nm of less than about 30%.2. The printed article of having an average transmittance of less than 0.01% for the wavelengths between 400 nm and 700 nm.3. The printed article of having an average transmittance of less than 0.1% for wavelengths between 380 nm and 800 nm.4. The printed article of having an average transmittance of less than 0.01% for wavelengths between 380 nm and 800 nm.5. The printed article of having an average transmittance of greater than 75% for the wavelengths between 830 nm and 900 nm.6. The printed article of claim 1 , wherein the optical filter has an average transmittance of greater than 50% for wavelengths between 900 nm and 980 nm.7. The printed article of having an average transmittance of greater than 70% for wavelengths between 900 nm and 980 nm.8. The printed article of having an average transmittance of greater than 50% for wavelengths between 800 nm and 1200 nm.9. The printed article of claim 1 , having an average ...

Effective media retarder films with spatially selective birefringence reduction

A retarder film provides a first light retardation and can be heat processed in one or more selected areas to provide a second light retardation in the selected area(s). The retarder film may have an absorption characteristic such that the heat processing can be carried out by selectively exposing the film to a suitable radiant beam. The retarder film is composed of a stack of contiguous ultrathin layers configured to provide an effective optical medium for visible light. Visible light propagates through the stack as an effective medium having effective refractive indices along principal x-, y-, and z-axes. At least some of the ultrathin layers possess intrinsic birefringence, and the effective indices of the stack are functions of the intrinsic refractive indices of the constituent ultrathin layers. The heat processing is carried out so that the ultrathin layer stack structural integrity is not substantially altered in the processed area(s).

SPECTRALLY SELECTIVE RETROREFLECTIVE SYSTEM

A retroreflective system is disclosed that includes a retroreflective sheet for retroreflecting light, and a light control film disposed on the retroreflective sheet. For a first wavelength, light incident on the light control film at each of a first and second angles of incidence is retroreflected. For a second wavelength, light incident on the light control film at the first, but not the second, angle of incidence is retroreflected. 1. A retroreflective system , comprising:a retroreflective sheet for retroreflecting light; anda light control film disposed on the retroreflective sheet, such that for a first wavelength, light incident on the light control film at each of a first and second angles of incidence is retroreflected, and for a second wavelength, light incident on the light control film at the first, but not the second, angle of incidence is retroreflected.2. The retroreflective system of claim 1 , wherein the light control film comprises a greater first viewing angle for the first wavelength and a smaller second viewing angle for the second wavelength.3. The retroreflective system of claim 2 , wherein the first viewing angle for the first wavelength is greater than about 50 degrees claim 2 , and the second viewing angle for the second wavelength is less than about 40 degrees.4. The retroreflective system of claim 1 , wherein the light control film is substantially transparent at the first wavelength.5. The retroreflective system of claim 1 , wherein the first angle of incidence is substantially equal to zero relative to a line normal to a plane of the light control film.6. The retroreflective system of claim 1 , wherein the second angle of incidence is at least 20 degrees claim 1 , or 30 degrees claim 1 , or 40 degrees claim 1 , or 50 degrees claim 1 , or 60 degrees relative to a line normal to a plane of the light control film.7. The retroreflective system of claim 1 , wherein the retroreflective sheet comprises at least one of microsphere beads and ...

INCONSPICUOUS OPTICAL TAGS AND METHODS THEREFOR

Tags are made from optical films to provide a pattern that is inconspicuous to ordinary observers, but that is detectable by a camera or other imaging device. The pattern is provided by first and second portions of a patterned layer, the first portions selectively filtering at least a portion of blue visible light from other visible light wavelengths. Filtering in the portion of the blue region helps make the pattern inconspicuous. The tags may also include an indicia layer configured to mark a location of the pattern, and a contrast enhancing layer disposed behind the patterned layer and configured to enhance a contrast of the pattern. In some cases, the first portions of the patterned layer may filter optical wavelengths other than blue, such as near-infrared light. The pattern may comprise machine-readable information, e.g., a linear bar code or a 2-D bar code. Associated methods and systems are also disclosed. 1. An optical tag having an inconspicuous pattern , comprising:a patterned layer having distinguishable first and second portions that define the pattern, the first portions selectively filtering at least a portion of blue visible light from other visible light wavelengths;an indicia layer disposed to overlap the pattern so as to mark a location of the pattern; anda contrast enhancing layer disposed behind the patterned layer and configured to enhance a contrast of the pattern.2. The tag of claim 1 , wherein the pattern comprises a machine-readable bar code pattern.3. The tag of claim 1 , wherein the pattern comprises a logo claim 1 , image claim 1 , text claim 1 , or symbol.4. The tag of claim 1 , wherein the patterned layer comprises a multilayer optical film that reflects and transmits visible light differently in the first and second portions of the patterned layer.5. The tag of claim 1 , wherein the patterned layer comprises an absorptive material that is present in the first portions more than in the second portions of the patterned layer claim 1 , ...

ANGULARLY AND SPECTRALLY SELECTIVE DETECTOR AND LIGHT SOURCE SYSTEMS

A detector system is disclosed that includes a detector that is sensitive to wavelengths in a detection wavelength range. The detector system further includes a light control film that is disposed on the detector and includes a plurality of alternating first and second regions. Each first region has a width W and a height H, where H/W≥1. Each first region has a substantially low transmission in a first portion of the detection wavelength range and a substantially high transmission in the remaining portion of the detection wavelength range. Each second region has a substantially high transmission in the detection wavelength range. 110-. (canceled)11. A detector system , comprising:a detector sensitive to wavelengths in a detection wavelength range; anda light control film disposed on the detector and comprising a plurality of alternating first and second regions, each first region having a width W and a height H, H/W≥1, each first region having a substantially low transmission in a first portion of the detection wavelength range and a substantially high transmission in a remaining portion of the detection wavelength range, each second region having a substantially high transmission in the detection wavelength range.12. The detector system of claim 11 , wherein the detection wavelength range is from about 800 to about 1600 and the first portion of the detection wavelength range is from about 900 nm to about 1100 nm.13. The detector system of claim 11 , wherein a viewing angle of the light control film in the first portion of the detection wavelength range is less than about 70 degrees along a first direction.14. The detector system of claim 11 , wherein the light control film comprises a major microstructured first surface having a plurality of alternating ribs and channels claim 11 , each channel at least partially filled with a first material to form one of the first regions claim 11 , each rib comprising a second material and forming one of the second regions.15. ...

TOUCH SENSITIVE PROJECTION SCREEN

Touch sensitive projection screens are disclosed. In particular, touch sensitive projection screen including drive electrodes, sense electrodes, and optical diffusers are disclosed. The touch sensitive projection screens are adapted for use on a horizontal surface. Touch sensitive projection screens including shrinkable layers are also disclosed. 110-. (canceled)12. The touch sensitive projection screen of being a front projection screen.13. The touch sensitive projection screen of claim 11 , wherein the anti-slip film comprises rubber.14. The touch sensitive projection screen of claim 11 , wherein the anti-slip film comprises a bottom structured surface such that when the projection screen is placed on a horizontal surface claim 11 , the structured surface contacts the horizontal surface.15. The touch sensitive projection screen of further comprising:a first layer adhered to the anti-slip film via an adhesive; anda second layer adhered to the first layer via an adhesive, the first and second layers preventing the projection screen from curling.16. The touch sensitive projection screen of claim 15 , wherein each of the first and second layers comprises PET.17. The touch sensitive projection screen of claim 11 , wherein:the plurality of spaced apart opaque drive electrodes and the plurality of first conductive traces are formed on the first support layer; andthe plurality of spaced apart opaque sense electrodes and the plurality of second conductive traces are formed on the second support layer.18. The touch sensitive projection screen of claim 17 , wherein each of the first and second support layers comprises PET.19. The touch sensitive projection screen of claim 11 , wherein the driving layer is adhered to the sensing layer via an adhesive.20. The touch sensitive projection screen of claim 11 , wherein each of the first and second optical diffusers appears white when illuminated with white light.21. The touch sensitive projection screen of claim 11 , wherein the ...

SPECTRALLY SELECTIVE LIGHT CONTROL FILM

A light control film is disclosed that includes a plurality of spaced apart first regions. Each first region has a substantially low transmission in one or two of a first wavelength range from about 300 nm to about 400 nm, a second wavelength range from about 400 nm to about 700 nm, and a third wavelength range from about 700 nm to about 1200 nm, and a substantially high transmission in the remaining wavelength ranges. The light control film has a viewing angle of less than about 70 degrees along a predetermined first direction 1. A light control film comprising a plurality of spaced apart first regions , each first region having a substantially low transmission in one or two of a first wavelength range from about 300 nm to about 400 nm , a second wavelength range from about 400 nm to about 700 nm , and a third wavelength range from about 700 nm to about 1200 nm , and a substantially high transmission in remaining wavelength ranges , wherein the light control film comprises a first viewing angle of less than about 70 degrees along a predetermined first direction.2. The light control film of comprising a major microstructured first surface having a plurality of alternating ribs and channels claim 1 , each channel at least partially filled with a first material to form one of the first regions in the plurality of spaced apart first regions claim 1 , each rib having a substantially high transmission in each wavelength range the first regions have a substantially low transmission in.3. A light control film comprising a plurality of spaced apart first regions and a second region claim 1 , each first region having a width W and a height H claim 1 , H/W≥1 claim 1 , each first region having a substantially high transmission in a predetermined first wavelength range and a substantially low transmission in a predetermined non-overlapping second wavelength range claim 1 , the second region having substantially high transmission in each of the predetermined first and second ...

OPTICAL CAMOUFLAGE FILTERS

An article includes an optical filter that comprises a wavelength selective reflective layer and at least one wavelength selective absorbing layer. The optical filter has visible transmittance between 400 nm-700 nm of less than about 30% and near infrared transmittance at 830 nm-900 nm greater than about 30%. 1. An article that includes an optical filter , the optical filter comprising:a wavelength selective reflective layer; andat least one wavelength selective absorbing layer, wherein the optical filter has average visible transmittance for wavelengths between 400 nm-700 nm less than about 30% and average near infrared transmittance for wavelengths between 830 nm-900 nm greater than about 30%.2. The article of claim 1 , wherein average visible transmittance for wavelengths between 400 nm-700 nm is less than about 5%.3. The article of claim 1 , wherein average near infrared transmittance for wavelengths between 830 nm-900 nm is greater than about 50%.4. The article of claim 1 , wherein the wavelength selective reflective layer comprises an interference filter.5. The article of claim 1 , wherein the wavelength selective reflective layer comprises a multilayer optical film.6. The article of claim 1 , wherein the wavelength selective reflective layer comprises a reflective polarizer.7. The article of claim 1 , wherein the wavelength selective absorbing layer comprises one or both of a wavelength selective dye and a wavelength selective pigment.89-. (canceled)10. The article of claim 1 , wherein the at least one wavelength selective absorbing layer comprises a first wavelength selective absorbing layer and a second wavelength selective absorbing layer claim 1 , and the wavelength selective reflective layer is between the first wavelength selective absorbing layer and the second wavelength selective absorbing layer.1113-. (canceled)14. The article of claim 1 , wherein the optical filter comprises a sealant layer.1516-. (canceled)17. The article of claim 1 , wherein the ...

High transmission flux leveling multilayer optical film and related constructions

A reflective film includes microlayers arranged into optical repeat units, each optical repeat unit including a negatively birefringent microlayer. The microlayers are tailored to provide the film with on-axis polarizing properties, such that normally incident light polarized along a block axis is substantially reflected and normally incident light polarized along a pass axis is substantially transmitted. On-axis transmission for the block axis may be <20%, and on-axis transmission for the pass axis may be >70%. The microlayers also provide the film with angularly dependent polarizing properties: p-polarized light incident in a block plane of incidence is substantially reflected at near-normal angles but substantially transmitted at an oblique angle. The film transmits unpolarized light incident in this plane more strongly at the oblique angle than at normal. The films can be used in direct-lit backlights, luminaires, and similar lighting systems for flux leveling to promote spatial brightness uniformity.

Optical film comprising birefringent naphthalate copolyester having branched or cyclic C4-C10 alkyl units

The present invention relates to multilayer optical films and birefringent copolyester films. The birefringent copolyester optical layer or birefringent copolyester film comprises a major amount of naphthalate units, ethylene units, and a minor amount of branched or cyclic C4 to C10 alkyl units. Also described are certain copolyester polymeric materials further comprising subunits of a phthalate ionomer such as dimethyl sulfosodium isophthtalate ionomer.

Negatively birefringent polyesters and optical films

Presently described are multilayer optical films, oriented polyester films, negatively birefringent copolyester polymers, fluorene monomers, and polyester polymers prepared from such fluorene monomers. In one embodiment, the multilayer optical film comprises at least one first birefringent optical layer; and at least one second optical layer having a lower birefringence than the first optical layer; wherein at least one of the optical layers comprises a negatively birefringent polyester polymer comprising a backbone and repeat units comprising at least one pendent aromatic group that is conformationally locked relative to the backbone.

Respirator having optically active exhalation valve

Various embodiments of a respirator (10) that includes a harness (13, 16), a mask body (12), and an exhalation valve (14) are disclosed. The exhalation valve (14) can include a valve seat (20) and a flexible flap (22) that is in engagement with the valve seat. The flexible flap can have one or more materials that can cause the flap to flash (26) when moving from a closed position to an open position or vice versa. The flashing valve can make it easier for a user to ascertain whether the valve is operating properly.

Internally patterned multilayer optical films with multiple birefringent layers

Conductive polymeric material

A melt-processable conductive material including a first continuous phase, a second continuous phase and a non-continuous phase. The first continuous phase includes a first polymer, the second continuous phase includes a second polymer, and the non-continuous phase includes a third polymer. The second continuous phase is co-continuous with the first continuous phase and the non-continuous phase is substantially contained within the first continuous phase. A plurality of conductive particles is distributed in the first polymer or at a boundary between the first continuous phase and the second continuous phase. The conductive particles form a conductive network.

Respirator having optically active exhalation valve

Various embodiments of a respirator (10) that includes a harness (13, 16), a mask body (12), and an exhalation valve (14) are disclosed. The exhalation valve (14) can include a valve seat (20) and a flexible flap (22) that is in engagement with the valve seat. The flexible flap can have one or more materials that can cause the flap to flash (26) when moving from a closed position to an open position or vice versa. The flashing valve can make it easier for a user to ascertain whether the valve is operating properly.

Internally patterned multilayer optical films with multiple birefringent layers

A reflective film includes interior layers that selectively reflect light by constructive or destructive interference, the layers extending from a first to a second zone of the film. The interior layers include a first set of layers composed of a first material and a second set of layers composed of a different second material. The first and second sets of layers are both birefringent in the first zone, but at least some of the layers have reduced birefringence in the second zone. The reduced birefringence produces a second reflective characteristic in the second zone that differs from a first reflective characteristic in the first zone, this difference not being substantially attributable to any thickness difference between the first and second zones. The film may also incorporate absorbing agents to assist in the manufacture or processing of the film. Related methods and articles are also disclosed.

capacitors and method of manufacturing a capacitor

a presente invenção refere-se a um capacitor de filme multi-camadas que tem uma pilha compósita disposta entre dois eletrodos, sendo que a pilha compósita inclui pelo menos uma camada termoplástica condutiva e pelo menos uma camada termoplástica isolante. a espessura total das camadas condutivas é de pelo menos 3 vezes a espessura total das camadas isolantes. as camadas condutivas podem incluir um polímero termoplástico misturado com partículas condutivas a uma concentração mais alta do que o limite de percolação. The present invention relates to a multilayer film capacitor having a composite stack disposed between two electrodes, the composite stack comprising at least one conductive thermoplastic layer and at least one insulating thermoplastic layer. The total thickness of the conductive layers is at least 3 times the total thickness of the insulating layers. Conductive layers may include a thermoplastic polymer mixed with conductive particles at a concentration higher than the percolation limit.

Effective media retarder films with spatially selective birefringence reduction

A retarder film provides a first light retardation and can be heat processed in one or more selected areas to provide a second light retardation in the selected area(s). The retarder film may have an absorption characteristic such that the heat processing can be carried out by selectively exposing the film to a suitable radiant beam. The retarder film is composed of a stack of contiguous ultrathin layers configured to provide an effective optical medium for visible light. Visible light propagates through the stack as an effective medium having effective refractive indices along principal x-, y-, and z-axes. At least some of the ultrathin layers possess intrinsic birefringence, and the effective indices of the stack are functions of the intrinsic refractive indices of the constituent ultrathin layers. The heat processing is carried out so that the ultrathin layer stack structural integrity is not substantially altered in the processed area(s).

Respirator having optically active exhalation valve

Various embodiments of a respirator (10) that includes a harness (13, 16), a mask body (12), and an exhalation valve (14) are disclosed. The exhalation valve (14) can include a valve seat (20) and a flexible flap (22) that is in engagement with the valve seat. The flexible flap can have one or more materials that can cause the flap to flash (26) when moving from a closed position to an open position or vice versa. The flashing valve can make it easier for a user to ascertain whether the valve is operating properly.

Stabilized infrared absorbing dispersions

A dispersion, a resin containing the dispersion and polymer film formed from the resin are disclosed. The dispersion includes an infrared light absorbing pigment including organo-metallic particles being less than 1.5 micrometer or less than one micrometer in size. The dispersion also includes a dispersant including phosphorus and a polyol.

Display system with finger sensing

A display system for sensing a finger of a user applied to the display system includes a display panel; a sensor for sensing the finger; a sensing light source configured to emit a first light having a first wavelength W1; and a reflective polarizer disposed between the display panel and the sensor. For a substantially normally incident light, an optical transmittance of the reflective polarizer versus wavelength for a first polarization state has a band edge such that for a first wavelength range extending from a smaller wavelength L1 to a greater wavelength L2 and including W1, where 30 nm ≤ L2 – L1 ≤ 50 nm and L1 is greater than and within about 20 nm of a wavelength L3 corresponding to an optical transmittance of about 50% along the band edge, the optical transmittance has an average of greater than about 75%.

Respirator having optically active exhalation valve

Various embodiments of a respirator (10) that includes a harness (13, 16), a mask body (12), and an exhalation valve (14) are disclosed. The exhalation valve (14) can include a valve seat (20) and a flexible flap (22) that is in engagement with the valve seat. The flexible flap can have one or more materials that can cause the flap to flash (26) when moving from a closed position to an open position or vice versa. The flashing valve can make it easier for a user to ascertain whether the valve is operating properly.

Spectrally selective retroreflective system

A retroreflective system is disclosed that includes a retroreflective sheet for retroreflecting light, and a light control film disposed on the retroreflective sheet. For a first wavelength, light incident on the light control film at each of a first and second angles of incidence is retroreflected. For a second wavelength, light incident on the light control film at the first, but not the second, angle of incidence is retroreflected.

Internally patterned multilayer optical films with multiple birefringent layers

Optical camouflage filters

An article includes an optical filter that comprises a wavelength selective reflective layer and at least one wavelength selective absorbing layer. The optical filter has visible transmittance between 400 nm - 700 nm of less than about 30% and near infrared transmittance at 830 nm - 900 nm greater than about 30%.

Inconspicuous optical tags and methods therefor

Tags are made from optical films to provide a pattern that is inconspicuous to ordinary observers, but that is detectable by a camera or other imaging device. The pattern is provided by first and second portions of a patterned layer, the first portions selectively filtering at least a portion of blue visible light from other visible light wavelengths. Filtering in the portion of the blue region helps make the pattern inconspicuous. The tags may also include an indicia layer configured to mark a location of the pattern, and a contrast enhancing layer disposed behind the patterned layer and configured to enhance a contrast of the pattern. In some cases, the first portions of the patterned layer may filter optical wavelengths other than blue, such as near-infrared light. The pattern may comprise machine-readable information, e.g., a linear bar code or a 2-D bar code. Associated methods and systems are also disclosed.

Extrudable urethane release coating

Described herein is a release material comprising: a blend comprising: releasing agent comprising a urethane polymer derived from a polyvinyl polymer containing active hydroxyl groups and an aliphatic isocyanate; and a carrier polymer, wherein more than 50% by weight of the carrier polymer is non-olefinic, and articles thereof.

Light source incorporating multilayer optical film

A light source includes a lightguide having a top side comprising an optical film, a bottom side comprising a diffuse reflector, and an input side extending between the top and bottom sides. An illumination source is disposed proximate the input side of the lightguide. The optical film has adjacent first and second zones, each zone extending substantially an entire thickness of the optical stack or an entire thickness of at least one optical packet of the optical film. Light enters the lightguide from the light source propagating within the lightguide and being either reflected or transmitted by the optical film primarily by optical interference. For at least one first incidence angle and at least one wavelength, the first and second zones of the optical film have substantially equal optical transmittance. For at least one second incidence angle and at least one wavelength, the second zone has substantially greater optical transmittance than the first zone of the optical film.

Optical Systems

An optical assembly includes an integral lens assembly having one or more lenses bonded to each other with spaced apart major first and second lens surfaces. First and second optical films are bonded to respective major first and second lens surfaces. The first and second optical films includes a plurality of polymeric layers. Each of the polymeric layers have an average thickness of less than about 500 nm. For a substantially normally incident light and a visible wavelength range the plurality of polymeric layers in the first optical film has an average optical transmittance and an average optical reflectance of greater than about 70% for a first polarization state and an orthogonal second polarization state, respectively. The plurality of polymeric layers in the second optical film has an average optical transmittance of greater than about 70% for at least one of the first and second polarization states.

Multilayer optical film

A multilayer optical film includes a plurality of optical repeat units which may number less than about 175 in total and which may have a combined average thickness of less than about 20 micrometers. Each of the optical repeat units includes at least four individual layers which may include at least one polymeric A layer, at least two B layers, and at least one polymeric C layer. At least one layer in the at least four individual layers can have an average thickness of less than about 50 nm. An interlayer adhesion of the individual layers in the plurality of optical repeat units can be at least about 14 grams per inch when measured at a 90 degree peel angle. The multilayer optical film may be a reflective polarizer or a multilayer optical mirror.

Optical construction and display system

An optical construction includes a reflective polarizer and an optically diffusive film disposed on the reflective polarizer. The reflective polarizer includes an outer layer including a plurality of first particles partially protruding from a first major surface thereof to form a structured major surface. A first optically diffusive layer is conformably disposed on the structured major surface. The optically diffusive film includes a second optically diffusive layer including a plurality of nanoparticles dispersed therein, and a structured layer including a structured major surface. For a substantially normally incident light and a visible wavelength range from about 450 nm to about 650 nm and an infrared wavelength range from about 930 nm to about 970 nm, the second optically diffusive layer has an average specular transmittance Vs in the visible wavelength range and an average specular transmittance Is in the infrared wavelength range, where Is/Vs≥2.5.

Respirator having optically active exhalation valve

A respirator, comprising: a harness;a mask body; andan exhalation valve disposed on and attached to the mask body, wherein the exhalation valve comprises: a valve seat; a valve cover; and a flexible flap that is in engagement with the valve seat, the flexible flap comprising either a band shifting film or at least a specularly reflecting film that causes the flap to flash when moving from a closed position to an open position or vice versa, and wherein the valve cover is sufficiently transparent to enable the flexible flap to be seen through a solid portion of the valve cover.. The flashing valve can make it easier for a user to ascertain whether the valve is operating properly.

Film stacks for thin circular polarizers

A film stack includes an oriented first layer including polyvinyl alcohol disposed on an oriented second layer including naphthalene dicarboxylate containing copolyester resin. The oriented second layer has in-plane birefringence Δnxy<0.02.

Display system with finger sensing

A display system for sensing a finger of a user applied to the display system includes a display panel; a sensor for sensing the finger; a sensing light source configured to emit a first light having a first wavelength W1; and a reflective polarizer disposed between the display panel and the sensor. For a substantially normally incident light, an optical transmittance of the reflective polarizer versus wavelength for a first polarization state has a band edge such that for a first wavelength range extending from a smaller wavelength L1 to a greater wavelength L2 and including W1, where 30 nm≤L2−L1≤50 nm and L1 is greater than and within about 20 nm of a wavelength L3 corresponding to an optical transmittance of about 50% along the band edge, the optical transmittance has an average of greater than about 75%.

Integral Multilayer Optical Film

An integral multilayer optical film includes a plurality of interference layers; a structured layer disposed on the interference layers and including a plurality of particles dispersed in a binder; and a barrier layer disposed between the structured layer and the interference layers and co-extruded with the interference layers and the structured layer. The structured layer has a first major surface facing away from the interference layers and a second major surface facing the interference layers. The barrier layer causes the particles to impart a greater surface roughness to the first major surface than the second major surface so that when the optical film is illuminated with a light source, the optical film has a first average effective transmission T 1 when the first major surface faces the light source and a second average effective transmission T 2 when the first major surface faces away from the light source, where T 1 -T 2 ≥5%.

Optical Construction and Display System

An optical construction includes a reflective polarizer and an optically diffusive film disposed on the reflective polarizer. The reflective polarizer includes an outer layer including a plurality of first particles partially protruding from a first major surface thereof to form a structured major surface. A first optically diffusive layer is conformably disposed on the structured major surface. The optically diffusive film includes a second optically diffusive layer including a plurality of nanoparticles dispersed therein, and a structured layer including a structured major surface. For a substantially normally incident light and a visible wavelength range from about 450 nm to about 650 nm and an infrared wavelength range from about 930 nm to about 970 nm, the second optically diffusive layer has an average specular transmittance Vs in the visible wavelength range and an average specular transmittance Is in the infrared wavelength range, where Is/Vs≥2.5.

Optical systems

An optical assembly includes an integral lens assembly having one or more lenses bonded to each other with spaced apart major first and second lens surfaces. First and second optical films are bonded to respective major first and second lens surfaces. The first and second optical films includes a plurality of polymeric layers. Each of the polymeric layers have an average thickness of less than about 500 nm. For a substantially normally incident light and a visible wavelength range the plurality of polymeric layers in the first optical film has an average optical transmittance and an average optical reflectance of greater than about 70% for a first polarization state and an orthogonal second polarization state, respectively. The plurality of polymeric layers in the second optical film has an average optical transmittance of greater than about 70% for at least one of the first and second polarization states.

Multilayer opitical film

A multilayer optical film includes a plurality of optical repeat units which may number less than about 175 in total and which may have a combined average thickness of less than about 20 micrometers. Each of the optical repeat units includes at least four individual layers which may include at least one polymeric A layer, at least two B layers, and at least one polymeric C layer. At least one layer in the at least four individual layers can have an average thickness of less than about 50 nm. An interlayer adhesion of the individual layers in the plurality of optical repeat units can be at least about 14 grams per inch when measured at a 90 degree peel angle. The multilayer optical film may be a reflective polarizer or a multilayer optical mirror.

Film stacks for thin circular polarizers

A film stack includes co-stretched first and second layers. The first layer is stained with iodine and has a glass transition temperature of at least 5° C. greater than a glass transition temperature of the second layer. The second layer has in-plane birefringence of less than 0.02 and a retardance of less than 100 nm.

Respirator having optically active exhalation valve

Various embodiments of a respirator that includes a harness, a mask body, and an exhalation valve are disclosed. The exhalation valve can include a valve seat and a flexible flap that is in engagement with the valve seat. The flexible flap can have one or more materials that can cause the flap to flash when moving from a closed position to an open position or vice versa. The flashing valve can make it easier for a user to ascertain whether the valve is operating properly.

Display system with finger sensing

A display system for sensing a finger of a user applied to the display system includes a display panel; a sensor for sensing the finger; a sensing light source configured to emit a first light having a first wavelength W1; and a reflective polarizer disposed between the display panel and the sensor. For a substantially normally incident light, an optical transmittance of the reflective polarizer versus wavelength for a first polarization state has a band edge such that for a first wavelength range extending from a smaller wavelength L1 to a greater wavelength L2 and including W1, where 30 nm≤L2−L1≤50 nm and L1 is greater than and within about 20 nm of a wavelength L3 corresponding to an optical transmittance of about 50% along the band edge, the optical transmittance has an average of greater than about 75%.

Respirator having optically active exhalation valve

Respirator having optically active exhalation valve

Various embodiments of a respirator that includes a harness, a mask body, and an exhalation valve are disclosed. The exhalation valve can include a valve seat and a flexible flap that is in engagement with the valve seat. The flexible flap can have one or more materials that can cause the flap to flash when moving from a closed position to an open position or vice versa. The flashing valve can make it easier for a user to ascertain whether the valve is operating properly.