Abstract: An active matrix LED display has a light-dependent device for detecting the brightness of the display element and threshold voltage measurement circuitry for measuring a threshold voltage of a pixel the drive transistor. Compensation for ageing of the display element is thus provided by an optical feedback path, and compensation for drive transistor threshold variations is provided by measurement of the threshold voltage. This provides a reliable compensation scheme for the threshold voltage variations, while also providing ageing compensation.

Abstract: An array element circuit with an integrated impedance sensor is provided. The array element circuit includes an array element which is controlled by application of a drive voltage by a drive element; writing circuitry for writing the drive voltage to the drive element; and sense circuitry for sensing an impedance presented at the drive element.

Abstract: An active matrix electroluminescent display device has pixels using an amorphous silicon or microcrystalline silicon drive NMOS transistor (22) connected between the anode of the display element (2) and a power supply line (26). A storage capacitor (24) is connected between the anode of the display element and the gate of the drive transistor (22). An amorphous silicon or microcrystalline silicon second drive NMOS transistor (30) supplies a holding voltage to the anode of the display element (2). This arrangement enables the voltage across the display element to be held while the transistor gate drive voltage is stored on the storage capacitor. This enables an accurate current source pixel circuit to be implemented using NMOS transistors.

Abstract: An active-matrix device is provided which includes a plurality of array element circuits arranged in rows and columns; a plurality of source addressing lines each shared between the array element circuits in corresponding same columns; a plurality of gate addressing lines each shared between the array element circuits in corresponding same rows; a plurality of sensor row select lines each shared between the array element circuits in corresponding same rows, wherein each of the plurality of array element circuits includes: an array element which is controlled by application of a drive voltage by a drive element; writing circuitry for writing the drive voltage to the drive element, the writing circuitry being coupled to a corresponding source addressing line and gate addressing line among the plurality of source addressing lines and gate addressing lines; and sense circuitry for sensing an impedance presented at the drive element, the sense circuitry being coupled to a corresponding sensor row select line; and

Abstract: An active-matrix device is provided which includes a plurality of array element circuits arranged in rows and columns; a plurality of source addressing lines each shared between the array element circuits in corresponding same columns; a plurality of gate addressing lines each shared between the array element circuits in corresponding same rows; a plurality of sensor row select lines each shared between the array element circuits in corresponding same rows, wherein each of the plurality of array element circuits includes: an array element which is controlled by application of a drive voltage by a drive element; writing circuitry for writing the drive voltage to the drive element, the writing circuitry being coupled to a corresponding source addressing line and gate addressing line among the plurality of source addressing lines and gate addressing lines; and sense circuitry for sensing an impedance presented at the drive element, the sense circuitry being coupled to a corresponding sensor row select line; and

Abstract: An array element circuit with an integrated impedance sensor is provided. The array element circuit includes an array element which is controlled by application of a drive voltage by a drive element; writing circuitry for writing the drive voltage to the drive element; and sense circuitry for sensing an impedance presented at the drive element.

Abstract: A method of manufacturing a color active matrix display device comprises forming islands over a rigid carrier substrate, forming a plastic substrate over the rigid carrier substrate, forming an array of pixel circuits over the plastic substrate and forming a display layer over the array of pixel circuits. The rigid carrier substrate is then released from the plastic substrate and the plastic substrate then has channels defined by the islands. These are filled to define color filter portions. The formation of a plastic substrate on a rigid carrier, with the use of a subsequent lift off process, enables the circuit arrays to be made on very thin plastic sheets. The color filters can then be made on the outside of the LC cell. Depressions are formed in the plastic substrate registered to the circuit array, and these are filled in with color filter material, for example by ink jet printing.

Abstract: A method of manufacturing a colour active matrix display device comprises forming islands over a rigid carrier substrate, forming a plastic substrate over the rigid carrier substrate, forming an array of pixel circuits over the plastic substrate and forming a display layer over the array of pixel circuits. The rigid carrier substrate is then released from the plastic substrate and the plastic substrate then has channels defined by the islands. These are filled to define colour filter portions. The formation of a plastic substrate on a rigid carrier, with the use of a subsequent lift off process, enables the circuit arrays to be made on very thin plastic sheets. The colour filters can then be made on the outside of the LC cell. Depressions are formed in the plastic substrate registered to the circuit array, and these are filled in with colour filter material, for example by ink jet printing.

Abstract: A display device comprising an array of pixels, with gates of thin film transistors of the pixels in a row connected to a row conductor. Row driver circuitry provides row address signals for controlling the switching of the transistors of the pixels of the row including an ON gate voltage and an OFF gate voltage. Control circuitry shifts the ON gate voltage and the OFF gate voltage in dependence on drive and/or environmental conditions such as temperature and/or refresh rate. The control circuitry maintains a constant difference between the ON gate voltage and the OFF gate voltage. This allows the gap between the on and off voltages to be reduced, which results in power savings. The kickback voltage is kept constant so that kickback compensation is kept simple.

Abstract: A method of manufacturing a color active matrix display device comprises forming islands over a rigid carrier substrate, forming a plastic substrate over the rigid carrier substrate, forming an array of pixel circuits over the plastic substrate and forming a display layer over the array of pixel circuits. The rigid carrier substrate is then released from the plastic substrate and the plastic substrate then has channels defined by the islands. These are filled to define color filter portions. The formation of a plastic substrate on a rigid carrier, with the use of a subsequent lift off process, enables the circuit arrays to be made on very thin plastic sheets. The color filters can then be made on the outside of the LC cell. Depressions are formed in the plastic substrate registered to the circuit array, and these are filled in with color filter material, for example by ink jet printing.

Abstract: An addressing scheme is provided for a display having an array of current driven pixels. An input voltage is used for generating a desired source-drain current using a transistor operated with low duty cycle. This source-drain current is then passed through a drive transistor and the resulting gate-source voltage is stored on a capacitor for subsequent driving of the display element.

Abstract: An active matrix display device uses an amorphous silicon drive transistor for driving a current through an LED display element. First and second capacitors are connected in series between the gate and source of the drive transistor, with a data input to the pixel provided to the junction between the first and second capacitors. The second capacitor is charged to a pixel data voltage, and a drive transistor threshold voltage is stored on the first capacitor. This pixel arrangement enables a threshold voltage to be stored on the first capacitor, and this can be done each time the pixel is addressed, thereby compensating for age-related changes in the threshold voltage.

Abstract: In an active matrix display, each pixel has a storage capacitor for storing a voltage to be used for addressing a drive transistor. A discharge transistor is provided for discharging the storage capacitor thereby to switch off the drive transistor. The timing of this is controlled by a light-dependent device which is illuminated by the display element. The drive transistor is controlled to provide a constant light output from the display element, and the duration is controlled in dependence on the data voltage. Optical feedback is used to alter further the timing of operation of the discharge transistor to provide ageing compensation of the display element and compensation for changes in the drive transistor.

Abstract: A display has circuitry (50) which generates all possible pixel drive signal levels on separate signal level lines. A buffer (54) is associated with each signal level line. The outputs of the buffers are selectably switchable onto the columns. The signal levels for each column are stored in a memory (72) and the buffers are controlled in dependence on the stored signal levels. The response of the buffers is heavily dependent on the output load, and there is a very large variation in the output load of the buffers (54), as a function of the number of columns to which the buffer output is to be provided. The buffers are controlled in dependence on stored signal levels to ensure stability of the buffers for any output load.

Abstract: A display device comprising an array of pixels, with gates of thin film transistors of the pixels in a row connected to a row conductor. Row driver circuitry provides row address signals for controlling the switching of the transistors of the pixels of the row including an ON gate voltage and an OFF gate voltage. Control circuitry shifts the ON gate voltage and the OFF gate voltage in dependence on drive and/or environmental conditions such as temperature and/or refresh rate. The control circuitry maintains a constant difference between the ON gate voltage and the OFF gate voltage. This allows the gap between the on and off voltages to be reduced, which results in power savings. The kickback voltage is kept constant so that kickback compensation is kept simple.

Abstract: A display device has a plurality of pixels, each having a current-driven display element coupled between a first conductive layer and a second conductive layer, the second conductive layer being coupled to a current supply via a switchable device having a thin film component on a first area of a substrate. Each pixel has a first capacitive device having a first capacitor plate on a second area of the substrate, the first capacitor plate conductively coupled to the thin film component, a second capacitor plate and a first insulating layer between the first capacitor plate and the second capacitor plate. On top of the first capacitive device is a second capacitive device sharing the second capacitor plate, the second capacitive device including a third capacitor plate sharing the second conductive layer, and a second insulating layer between the second capacitor plate and the third capacitor plate.

Abstract: A display device comprises an array (12) of display pixels arranged in rows and columns and provided on a common substrate (18). A first row driver circuit (20) is for a first sub-set of the rows of pixels and a second row driver circuit (22) is for a second sub-set of the rows of pixels. The first row driver circuit (20) comprises an integrated circuit on a separate substrate to the common substrate of the display pixels, and the second row driver circuit (22) comprises circuitry integrated onto the common quality off-substrate row driver to be used for a partial display portion. For example, this may be part of the display which is used most often, for example in a stand by mode (and optionally also in a normal drive mode). This part of the display is then most prone to ageing and therefore benefits from the off-substrate IC row driver. The second sub-set of rows preferably comprises the rest of the display, and an on-substrate row driver can be used.

Abstract: A method of manufacturing a colour active matrix display device comprises forming islands over a rigid carrier substrate, forming a plastic substrate over the rigid carrier substrate, forming an array of pixel circuits over the plastic substrate and forming a display layer over the array of pixel circuits. The rigid carrier substrate is then released from the plastic substrate and the plastic substrate then has channels defined by the islands. These are filled to define colour filter portions. The formation of a plastic substrate on a rigid carrier, with the use of a subsequent lift off process, enables the circuit arrays to be made on very thin plastic sheets. The colour filters can then be made on the outside of the LC cell. Depressions are formed in the plastic substrate registered to the circuit array, and these are filled in with colour filter material, for example by ink jet printing.

Abstract: A liquid crystal display has a plurality of buffers 46 controlling a plurality of column lines. The buffers have a bias current control input 47 which is controlled, in the example by timing circuitry 50, to current during the row period for writing to each row of pixels. In particular, the row period may be divided between a drive period with a high buffer bias current and a voltage maintenance period with a lower buffer bias current.

Abstract: An active matrix display device comprises an array of picture elements, e.g. liquid crystal picture elements, first and second sets of address conductors (16, 18) extending in row and column directions respectively and connected with the picture elements, and a set of connection conductor lines (30?) extending in the same direction as one set of address conductors (18), each of which is connected to a respective one of the other set of conductors (16), and via which address signals are supplied to that other set. To avoid unwanted display artefacts, each connection conductor line (30?) extends from one side of the array and terminates adjacent its connection point (32) to its associated address conductor (16) and a respective complementary conductor line (30?) is provided which extends from close to the connection point (32) to the opposite side of the array, the complementary conductor line being electrically separate from the connection line (30?) and coupled to reference signal supply (40).