Koninklijke Philips Corporation N.v.

U.S. Philips Corporation

John R Hughes

Martin John Edwards

Ian D French

Stephen J Battersby

Jason Roderick Hector

Martin John Powell

Peter W Green

Jeremy N Sandoe

Steven Charles Deane

David Andrew Fish

David W Parker

A method is provided of determining the pixel drive signals to be applied to the pixels of an array of light emitting display elements arranged in rows and columns, with a plurality of the pixels in a row being supplied with current simultaneously along a respective row conductor. Target pixel drive currents are determined from a model of the pixel current-brightness characteristics. These are modified to take account of the voltage on the respective row conductor at each pixel resulting from the currents drawn from the row conductor by the plurality of pixels and the dependency of the pixel brightness characteristics on the voltage on the row conductor at the pixel. This addresses the problem of horizontal cross-talk that occurs in active matrix LED displays due to the finite output impedance of the current providing TFTs as well as the finite resistance of metals used to form power supply lines.

Light emitting display devices

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

Active matrix display device

A method of constructing an active matrix pixel device uses a universal active matrix (UAM) comprising a matrix array of switching elements whose spacing defines a base pitch and a pixel array comprising a matrix array of pixel electrodes whose spacing defines a pixel pitch. The pixel pitch is greater than the base pitch. A large proportion of the construction process can be carried out before the customization of the device. Using a common UAM enables a reduction in the time between the customer ordering the device and the completion time. The cost of meeting customer specific requirements for the fabrication of active matrix pixel devices is thus reduced.

Active matrix pixel device construction method

An active matrix display device comprises an array of picture elements, e.g. liquid crystal picture elements, first and second sets of address conductors ( ) extending in row and column directions respectively and connected with the picture elements, and a set of connection conductors ( ) extending in the same direction as the second set of address conductors ( ), each of which is connected to a respective one of the first set of conductors ( ) at the location of a picture element, and via which address signals are supplied to that first set. Picture elements other than those at the locations of the connections between the connection conductors and first set of address conductors are provided with a capacitance between their picture element electrode and their associated address conductor of the first set in order to compensate for the effects of a parasitic capacitance present between the picture element electrodes and the connection conductors which can lead to anomalies in the display outputs of the picture elements following their addressing.

A method of constructing an active matrix pixel device uses a universal active matrix (UAM) ( ) comprising a matrix array of switching elements ( ) whose spacing defines a base pitch and a pixel array comprising a matrix array of pixel electrodes ( ) whose spacing defines a pixel pitch. The pixel pitch is greater than the base pitch. A large proportion of the construction process can be carried out before the customisation of the device. Using a common UAM ( ) enables a reduction in the time between the customer ordering the device and the completion time. The cost of meeting customer specific requirements for the fabrication of active matrix pixel devices is thus reduced.

Display having universal active matrix

An active matrix display device of the kind having two terminal non-linear switching devices ( ) such as thin film diodes connected in series with the electro-optic, e.g. LC, display elements ( ) between associated row and column address conductors ( ), in which the display elements are driven using pulse width modulated data signals and a wide range of grey-scale levels is achieved by using selection signals whose form is determined such that the current flow through the switching devices upon selection is controlled in an appropriate manner. To this end, the selection signals can be shaped to provide a more constant charging level over the selection period.

Active matrix display devices and methods of driving such

A controller circuit ( ) for processing video data for an active matrix liquid crystal display device has processing circuitry for performing correction functions on the input video data (D) prior to being supplied to the drive circuit ( ) of the display device comprising gamma and color correction, and correction for reducing motion blur in the display picture. The correction circuits ( ) are organized such that correction for motion blur reduction ( ) is carried out before the gamma and color corrections ( ), which enables a beneficial decrease in semiconductor area required when implementing the circuitry in IC form through the size of field store ( ) and LUT ( ) components used for this function then being smaller. Gamma and color corrections are performed together using a single LUT. Correction for kickback may further be included, such correction preferably being arranged after the gamma and color corrections and using a separate LUT.

Controller circuit for liquid crystal matrix display devices

An active matrix display device of the kind having two terminal non-linear switching devices (,) such as thin film diodes connected in series with the electro-optic, e.g. LC, display elements (,) between associated row and column address conductors (,), in which the display elements are driven using pulse width modulated data signals and a wide range of grey-scale levels is achieved by using selection signals whose form is determined such that the current flow through the switching devices upon selection is controlled in an appropriate manner. To this end, the selection signals can be shaped to provide a more constant charging level the selection period.

An active matrix display device, having an array of picture elements (12) comprising electro-optic, for example LC, display elements (14) and associated switching devices (15), for example thin film diodes, driven by selection and data signals applied to sets of row and column address conductors (16, 17) respectively, which includes a reference circuit (34) comprising a switching device (35) connected to a capacitive element (36) and similarly driven periodically by selection signals and a reference data signal applied via one of the column address conductors (17), and an adjustment circuit which senses the voltage at the capacitive element (36), indicative of the operational behavior of the switching device (35), at particular times corresponding substantially to the termination of a selection signal applied to the reference circuit and which, according to the sensed voltage at that time, is operable to adjust the drive voltages used for the picture elements (12) so as to compensate for changes in the operational behavior of the switching device.

An image detector (1, 1a) has an array (2) of sensors (3) formed from layers of material provided on a substrate (4) and separated from a biasing electrode (5) by a radiation conversion layer (6) in which charge carriers are generated in response to incident radiation. Each sensor has a collecting electrode (7a, 7b) for collecting charge carriers generated in the radiation conversion layer (6), a capacitor (c) for storing charge and a switching element (8) having at least first and second electrodes (9 and 10) with one (10) of the first and second electrodes being coupled to the collecting electrode (7a, 7b) for enabling charge carriers stored at the sensor (3) to be read out. Each collecting electrode (7a, 7b) extends laterally beyond the associated switching element (8) on an insulating layer (12a, 12b) provided over the switching elements to form the associated capacitor (c) with an underlying reference electrode (12a, 12b) separated from the collecting electrode (7a, 7b) by the insulating layer (11a, 11b).

Image detector

A large area active matrix array (2) is manufactured by providing four substrates (1) each carrying a sub-array (21) having an active area (11) comprising a matrix of switching elements (30) and associated row and column conductors (41) and (42) for enabling addressing of individual switching elements (30). The row and column conductors (41) and (42) terminate in respective connecting leads (41a and 42a) extending beyond the active area (11). A portion (1a) of each substrate (1) and the connecting leads carried is removed so as to form a new substrate edge (1'a) adjacent each of two adjoining edges of the active area (11) and the substrates (1) are mounted onto a support (12) so that each new substrate edge is adjacent another new substrate edge (1'a) to form the large area array (2), thereby allowing the same pixel pitch to be maintained across the array (2). Each sub-array (2') may be fully tested before completion of the array (2) which should allow higher yields.

Method of manufacturing a large area active matrix array

An image detector (1) has a first substrate (10) carrying an electromagnetic radiation conversion layer (11) for converting incoming electromagnetic radiation (A) with a first range of wavelengths into outgoing electromagnetic radiation (B) with a second different range of wavelengths and a photodetector array (21) is carried by a second substrate (20) and responsive to the second range of wavelengths for detecting outgoing electromagnetic radiation (B) emitted by the layer (11). The second substrate (20) is mounted to the first substrate (10) by a mounting arrangement (40) defining an insulative space (50) which provides good electrical isolation between the photodetector array (21) and the electromagnetic radiation conversion layer (11). The use of separate substrates (10 and 20) enables the photodetector array (21) and electromagnetic radiation conversion layer (11) to be manufactured independently of one another using optimum processes for producing the desired properties for the photodetector array (21) and electromagnetic radiation conversion layer (11), respectively.

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Horley, United Kingdom

John R Hughes