Sensing displays utilizing light emitting diodes

• US 9,207,851 B1
• Filed: 01/24/2011
• Issued: 12/08/2015
• Est. Priority Date: 01/22/2010
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Perceptive Pixel Incorporated (Microsoft Corporation)
• Inventors: Han, Jefferson Y.
• Primary Examiner(s): Eurice, Michael J
• Application Number:
  US13/012,100
• Time in Patent Office: 1,779 Days
• Field of Search: 235/462.01, 235/462.09, 235/462.25, 235/462.42, 235/472.01, 235/454, 235/462.45, 345/173, 345/175, 345/156, 345/87, 345/104, 345/174, 345/102, 345/179, 345/176, 345/98, 345/100, 846/45, 846/22, 846/59, 847/23, 257/E31.096
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• CPC Class Codes: G06F 2203/04808 Several contacts: gestures triggering a specific function, e.g. scrolling, zooming, right-click, when the user establishes several contacts with the surface simultaneously; e.g. using several fingers or a combination of fingers and pen
• CPC Class Codes: G06F 3/0308 comprising a plurality of distinctive and separately oriented light emitters or reflectors associated to the pointing device, e.g. remote cursor controller with distinct and separately oriented LEDs at the tip whose radiations are captured by a photo-detector associated to the screen
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures

Abstract

A matrix of light emitting diodes is positioned behind a liquid crystal layer of a display device. The light emitting diodes operate in both light emitting and light detecting modes. Consequently, the display device is able to sense objects or fingers approaching or in contact with a front display surface of the display device based on changes in incident light on the matrix that are observed by one or more of the light emitting diodes operating in the light detecting mode.

Claims

1. A display device configured to display output images and sense input user interaction comprising:

a liquid crystal layer including individually addressable pixels of liquid crystal material;

first driving circuitry that selectively controls transmissivity to light in the visible spectrum of individual ones of the pixels of the liquid crystal layer;

a matrix of light emitting diodes positioned behind the liquid crystal layer, the matrix including a plurality of light emitting diodes being arranged in rows and columns;

second driving circuitry that operates a first subset of spatially distributed light emitting diodes to alternatively emit light through the liquid crystal layer and detect light transmitted through the liquid crystal display, while the first subset of spatially distributed light emitting diodes is being operated to emit light, the second driving circuitry operates a second subset of spatially distributed light emitting diodes of the plurality of light emitting diodes to detect light transmitted through the liquid crystal layer, and while the first subset of light emitting diodes is being operated to detect light, the second driving circuitry operates the second subset of spatially distributed light emitting diodes to detect light transmitted through the liquid crystal layer, and wherein each of the first and second subsets of spatially distributed light emitting diodes emit light to provide a uniform plane of light as backlight illumination for the liquid crystal layer;

an electronic storage device that stores output representative of a light level received from each of the plurality of light emitting diodes when the light emitting diode is being operated to detect light; and

a processing element that determines that a user input event has occurred proximate to a light emitting diode, if a light level detected by the light emitting diode is in a predetermined range.

2. The display device of claim 1 further comprising an enhancement film positioned between the liquid crystal layer and the matrix of light emitting diodes.

3. The display device of claim 1 wherein the processing element determines if more than one touch input has occurred based on results of processing the output received from the light emitting diodes that is stored in the electronic storage device.

4. The display device of claim 1 wherein the second driving circuitry dynamically modifies an intensity of light emitted by light emitting diodes operated to emit light in accordance with a video signal, and responsive to the intensity of light being dynamically modified, adaptively modify the predetermined range to account for the intensity of light being dynamically modified.

5. The display device of claim 4 wherein the intensity of light emitted by the light emitting diodes is dynamically reduced to increase an effective contrast ratio of an output image displayed by the display device.

6. The display device of claim 1 further comprising a controller that coordinates operation of the first driving circuitry and the second driving circuitry such that the second driving circuitry causes certain ones of the light emitting diodes to detect light while the first driving circuitry concurrently causes corresponding ones of the individually addressable pixels of the liquid crystal layer that would be illuminated by the certain light emitting diodes if operated in the light emitting mode to be transmissive to visible light.

7. The display device of claim 6 wherein the controller configured to controls the second driving circuitry to cause the light emitting diodes to operate in a pattern that is temporally modulated and controls the first driving circuitry to cause the individually addressable pixels of the liquid crystal layer to operate in synchronization with the pattern such that pixels of the liquid crystal layer are set to a transmissize state when corresponding light emitting diodes operated to detect light.

8. The display device of claim 6 wherein the controller controls the second driving circuitry to cause the light emitting diodes to operate in a pattern that is spatially modulated and controls the first driving circuitry to cause the individually addressable pixels of the liquid crystal layer to operate in synchronization with the pattern such that pixels of the liquid crystal layer are set to a transmissize state when corresponding light emitting diodes operate in the light detecting mode.

9. The display device of claim 8 wherein the controller controls the second driving circuitry to cause the light emitting diodes to operate in a pattern that is spatially modulated in accordance with a basis function.