Cambridge Display Technology Limited

Cambridge Touch Technologies Ltd.

Synaptics Corporation

Promethean Limited

Light Blue Optics Ltd

Stmicroelectronics S.a.

Paul Richard Routley

Euan Christopher Smith

Arokia Nathan

Babak Bastani

Riccardo Micci

Adrian James Cable

Joseph Kurth Reynolds

Kirk Hargreaves

Michael Robert Astley

Gareth John McCaughan

David Ely

Julian Haines

Xiang Cheng

Jiahao Li

Nicholas A Lawrence

Jonathan James Michael Halls

Matteo Vit

John Andrew

William Goodchild

Peter William Tudor Mash

Clare Foden

Olivier Le-Briz

Julian Hall

Nic Lawrence

Lilian Lacoste

An apparatus () for processing signals from a touch panel () is described. The touch panel () includes a layer of piezoelectric material () disposed between a number of sensing electrodes () and at least one common electrode (). The apparatus () includes a capacitive touch controller () for connection to the sensing electrodes (). The apparatus () also includes a switch network () including a number of inputs for connection to some or all of the sensing electrodes (), and an output connected to system ground or a common mode voltage (V). The apparatus () also includes a second circuit () for connection to the at least one common electrode () and configured to generate, based on signals received from the at least one common electrode, a second pressure signal () indicative of a total pressure applied to the touch panel (). The apparatus () also includes a controller () configured to control the switch network () to couple any connected sensing electrodes () to system ground or the common mode voltage (V) during a pressure measurement period, and to determine an estimate of the total pressure based on the second pressure signal during the pressure measurement period.

Pressure sensing apparatus and method

An apparatus for processing signals from a touch panel. The touch panel includes a layer of piezoelectric material disposed between a number of sensing electrodes and one or more common electrodes. The apparatus includes a capacitive touch controller for connection to the sensing electrodes and a switch network including inputs for connection to the sensing electrodes and an output connected to system ground or a common mode voltage. The apparatus includes a circuit for connection to the common electrodes and to generate, for each common electrode, a corresponding pressure signal indicative of a pressure applied to the touch panel proximate to that common electrode. The apparatus includes a controller to control the switch network to couple any connected sensing electrodes to system ground or the common mode voltage during a pressure measurement period, and to sample the one or more second pressure signals during the pressure measurement period.

Touch panel system with piezoelectric pressure sensing

A method includes receiving (S), from a touch panel (), force values () corresponding to a plurality of piezoelectric sensors (), Each piezoelectric sensor corresponds to a physical location (xm, yn) on the touch panel. The method also includes receiving (S) one or more user touch locations corresponding to user touches, The method also includes excluding (S) all force values () corresponding to physical locations within a distance of a user touch location, and setting the remaining force values () as valid force values (S). The method also includes interpolating and/or extrapolating (S), based on the valid force values, one or more reconstructed force values () corresponding to same physical locations (xm, yn) as the respective excluded force values ().

Pressure signal processing

An apparatus () for processing signals from a touch panel () is described. The touch panel () includes a layer of piezoelectric material () disposed between a plurality of sensing electrodes () and at least one common electrode (). The apparatus () includes a first circuit () for connection to the plurality of sensing electrodes (). The first circuit () is configured to generate a plurality of first pressure signals (). Each first pressure signal () corresponds to one or more sensing electrodes () and is indicative of a pressure acting on the touch panel () proximate to the corresponding one or more sensing electrodes (). The apparatus also includes a second circuit () for connection to the at least one common electrode (). The second circuit () is configured to generate a second pressure signal () indicative of a total pressure applied to the touch panel (). The apparatus also includes a controller () configured to determine an estimate of the total pressure based on a weighted difference of the second pressure signal () and a sum over the plurality of first pressure signals ().

Mitigation of external fields in piezoelectric sensors

An apparatus () for processing signals from a touch panel () is described. The touch panel () includes a layer of piezoelectric material () disposed between a plurality of sensing electrodes () and at least one common electrode (). The apparatus () includes a first circuit () for connection to the plurality of sensing electrodes (). The first circuit () is configured to generate one or more first pressure signals (). Each first pressure signal () corresponds to one or more sensing electrodes () and is indicative of a pressure acting on the touch panel () proximate to the corresponding one or more sensing electrodes (). The apparatus also includes a second circuit () for connection to the at least one common electrode (). The second circuit () is configured to generate a second pressure signal () indicative of a total pressure applied to the touch panel (). The apparatus also includes a controller () configured to determine an estimate of the total pressure based on a weighted difference of the second pressure signal () and a sum over the one or more first pressure signals ().

A method includes receiving (S), from a touch panel (), force values () corresponding to a plurality of piezoelectric sensors (). Each piezoelectric sensor corresponds to a physical location (x, y) on the touch panel. The method also includes receiving (S) an identification of which, if any, of the force values () are influenced by coupling to external electric fields. The method also includes, in response to one or more force values () being identified as influenced by coupling to external electric fields (S), setting the corresponding force values () as excluded force values (S), and setting the remaining force values () as valid force values (S). The method also includes interpolating and/or extrapolating (S), based on the valid force values, one or more reconstructed force values () corresponding to same physical locations (x, y) as the respective excluded force values ().

Apparatus () for processing signals from a touch panel () is described. The touch panel () includes a layer of piezoelectric material () disposed between a plurality of sensing electrodes () and at least one common electrode (). The apparatus () includes a first circuit () for connection to the plurality of sensing electrodes (). The first circuit () is configured to generate a plurality of first pressure signals (). Each first pressure signal () corresponds to one or more sensing electrodes () and is indicative of a pressure acting on the touch panel () proximate to the corresponding one or more sensing electrodes (). The apparatus () also includes a second circuit () for connection to the at least one common electrode (). The second circuit () is configured to generate a second pressure signal () indicative of a total pressure applied to the touch panel (). The apparatus () also includes a controller () configured to determine an external interference signal () based on a weighted sum over the second pressure signal () and the plurality of first pressure signals (). The controller () is also configured to compare the external interference signal () against a pre-calibrated threshold (V). The controller is also configured, in response to the external interference signal () being greater than or equal to the pre-calibrated threshold (V), to output an interference flag (Int) indicating that the first and second pressure signals () are influenced by coupling to one or more external electrical fields.

Various approaches to touch sensing systems are disclosed As an example, a touch sensing system is disclosed that includes: an optical beam source to provide an optical beam; a pair of controllable beam deflectors comprising at least first and second beam deflectors, wherein the first beam deflector is configured to deflect the optical beam through a first angle towards a touch sensing region, and wherein the second beam deflector is configured to deflect scattered light from an object in the touch sensing region through a second angle; a detector, in particular a detector array; and an imaging system to image the deflected scattered light from the second beam deflector onto the detector array. The first and second beam deflectors are controlled in tandem to scan the touch sensing region.

Scanning touch systems

We describe a touch sensing system projecting light defining a touch sheet above a surface and a camera to capture a touch image of light scattered by a pen intersecting the touch sheet. A signal processor identifies a lateral location of the pen. The pen includes a light source to provide a light signal, and the system also includes two photodiodes to detect the signal from the pen. The touch detection is augmented by modelling the signals received at the photodiodes, dependent on the distance and angle of a pen, and using this to derive a probability of the observed received signals given the pen location determined from the touch sheet. This information can be used, for example, to allocate identities to the pens.

Touch sensing systems

We describe a touch sensitive holographic image display device for holographically projecting a touch sensitive image at an acute angle onto a surface on which the device is placed. The device includes holographic image projection optics comprising at least one coherent light source illuminating a spatial light modulator (SLM), output optics to project a hologram onto an acute angle surface, and a remote touch sensing system to remotely detect a touch of a location within or adjacent to the holographically displayed image. A control system is configured to provide data defining an image for display, to receive detected touch data, and to control the device responsive to remote detection of a touch of a the displayed image.

Touch sensitive holographic displays

We describe a touch sensitive image display device including: an image projector to project a displayed image onto a surface; a touch sensor light source to project a plane of light above the displayed image; a camera to capture a touch sense image from light scattered from the plane of light by an approaching object; and a signal processor to process the touch sense image to identify a location of the object. The touch sensor light source is amplitude modulated, and signal processor is further configured to process a plurality of the touch sense images captured when the touch sensor light source is off to compensate for ambient light in a touch sense image captured when the touch sensor light source is on.

Touch-sensitive display devices

A touch sensitive device, the device comprising: a touch sensor light source to project a plane of light above a surface; a camera directed to capture a touch sense image from a region including at least a portion of said plane of light, said touch sense image comprising light scattered from said plane of light by a plurality of said objects simultaneously approaching or touching said surface; a signal processor coupled to said camera, to process a said touch sense image from said camera to identify a lateral location of each of said objects; and an output object position output, to provide output object positions for said plurality of objects; and wherein said signal processor is further configured to: input a succession of said touch sense images; process each said touch sense image to identify a plurality of candidate object touch positions; and filter said candidate object touch positions from said successive touch sense images to link said candidate object touch positions to previously identified output object positions for said plurality of objects; and update said previously identified output object positions using said linked candidate object touch positions.

Touch sensitive display devices

This invention relates to methods, apparatus, and computer program code for driving an active matrix display, in particular an organic light emitting diode (OLED) display, with reduced power consumption.

Active matrix display drive control systems

This invention relates to systems, methods and apparatus for driving organic light emitting diodes (OLED) displays, in particular those using multi-line addressing (MLA) techniques. Embodiments of the invention are particularly suitable for use with so-called passive matrix OLED displays. A current drive system for an electroluminescent display, the system comprising: a plurality of current mirrors having a plurality of outputs for driving a plurality of drive electrodes of said display, each said current mirror having a reference signal input; and an automatic selector coupled to said current mirror outputs to automatically select a said output for providing reference signal inputs to said current mirrors.

Growing community of inventors

Longstanton, United Kingdom

Paul Richard Routley