Display device

A display device comprises an array of organic light emitting diode (OLED) pixels 1 which emit light towards a viewing surface 3, a light-transmissive, light scattering layer 5 in the path of light from the pixels towards the viewing surface 3, and a light baffle 22 located adjacent the viewing surface 3. The light baffle 22 comprises reflective walls arranged to extend in a direction from the viewing surface towards the scattering layer. The walls are arranged to reflect light rays which have been totally internally reflected at the viewing surface back towards the scattering layer 15. The walls are configured to have an aspect ratio defined as the ratio of the separation between adjacent walls to the height of the walls, having a value between 1.5:1 and 2:1. The scattering layer improves efficiency, whilst the light baffle reduces blurring caused by scattered light which has been reflected internally.

Semiconductor application method and product

Touch sensing systems

An optical touch sensing system comprises a touch sensor light source to project light above a surface, an optical touch sensor to capture a touch sense signal from a region above said surface, a pen to optically respond to said projected light, and a touch processing system comprising a signal processor. The signal processor identifies a lateral location of the pen on the surface from the optical response. The signal processor comprises a wireless communication system to send a wireless message to the pen, and the pen comprises an electronic controller coupled to a receiver to receive the wireless message from the signal processor. The projected light may be encoded to send the message to the pen. A brightness of the projected light may be modulated to define bright, touch detecting intervals and intervening intervals. The message may be encoded in the bright intervals or in the intervening intervals. The message may comprise an instruction to the pen to perform an action. The instruction ...

AMOLED drive circuity including distributed cascode transistor

An active matrix OLED (AMOLED) display panel comprising: a plurality of OLED pixels each having an associated current-programmed pixel drive circuit 180, said pixel drive circuit having a pixel select line SEL and a current programming input for programming an OLED pixel when said pixel select line is active; at least one distributed cascode transistor 202a-d shared between a set of said pixel drive circuits and comprising a set of transistors each having an input connection, an output connection and a control connection, wherein each transistor of said set is in physical proximity to a respective one of said pixel drive circuits and has said output connection connected to said current programming input of said respective one of said pixel drive circuits, wherein said input connections of said transistors of said set are connected together in parallel, said output connections of said transistors of said set are connected together in parallel, and said control connections of said transistors ...

Method of semiconductor element application

During manufacture of a backplane for example for a colour pixel OLED display, a plurality of semiconducting elements in the form of chiplets are deposited on a substrate using a method comprising defining a plurality of element positions on a substrate; applying semiconductor elements 10 to the substrate; forming a first planarization layer (Fig. 4B: 405) over the applied semiconductor elements wherein the upper surface at element positions where a semiconductor element is present has a height of at least H1 above the substrate, which is greater than a maximum height H2 of the upper surface in the defined element positions where a semiconductor element is not present; depositing a plurality of conductive pads (Fig. 4C: 407) on the upper surface of the first planarization layer at the plurality of defined element positions; removing conductive pads such that only conductive pads deposited on the upper surface at element positions having the upper surface height of at least H1 are removed ...

Pixel driver circuitry for active matrix OLED display

We describe a pixel driver circuit for an active matrix OLED display, the circuit comprising: a current programming line 322 to source or sink a programming current for said pixel driver circuit; a range control line 326 to receive a range control signal; a scaling circuit 302 coupled to said current programming line and to said range control line, wherein said scaling circuit is configured to provide a scaled current output 320 dependent on said programming current scaled by said range control signal; and an OLED driver circuit 304 coupled to said scaled current output of said scaling circuit, wherein said OLED driver circuit has a pixel select line SEL1 and is configured such that activating said pixel select line programs said OLED driver circuit to drive an OLED coupled to said OLED driver circuit with a current dependent on said scaled current output of said scaling circuit.

Pixel driver circuits

An active matrix OLED pixel driver circuit comprises: a power supply connection to receive a power supply; an OLED drive connection to drive an OLED; an OLED drive transistor having an input, output and control connection, wherein said input connection is coupled to said power supply connection and said output connection is coupled to said OLED drive connection; a gate capacitor having a first plate coupled to said control connection of said OLED drive transistor and a second plate coupled to a common capacitor connection; a first select transistor having an input connection, an output connection coupled to said first plate of said gate capacitor, and a control connection coupled to a first pixel select connection of said OLED pixel driver circuit; an input capacitor having a first plate coupled to said input connection of said first select transistor and a second plate coupled to said common capacitor connection; and a second select transistor having an input connection, an output connection ...