Optical touch device with pixilated light-turning features

• US 9,019,240 B2
• Filed: 11/30/2011
• Issued: 04/28/2015
• Est. Priority Date: 09/29/2011
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Gruhlke, Russell Wayne, Yin, Ye, Wang, Lai, Burns, David William
• Primary Examiner(s): Bibbins, Latanya
• Application Number:
  US13/307,353
• Publication Number:
  US 20130082980A1
• Time in Patent Office: 1,245 Days
• Field of Search: 345/175, 362600-629
• US Class Current: 345/175
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• CPC Class Codes: G02B 6/0011 the light guides being planar or of plate-like form
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421

Abstract

This disclosure provides systems, methods and apparatus for a touch screens configured to determine a position of a touch event by selectively redirecting light to correlated locations on a light sensor. In one aspect, the touch screen apparatus can include a light guide forming a touch interface, a light source for injecting light into the light guide, a light sensor for detecting the injected light, and a pixilated light-turning layer. The pixilated light-turning layer can include a plurality of light-turning features forming pixels. The pixels can receive incident light corresponding to the emitted light scattered by an object contacting the light guide. The pixels can redirect the incident scattered light towards the light sensor such that light selectively propagates to one or more correlated light receiving locations. A processor can map the light receiving location to an area contacted by the object, thereby determining a position of a touch event.

Claims

1. A method of detecting touch events on a touch screen, the method comprising:

receiving light directed from a pixilated light-turning layer at a light sensor location on a light sensor, the pixilated light-turning layer including pixels configured to redirect at least a portion of incident light scattered by an object above a light guide to the light sensor location;

mapping the light sensor location receiving the incident light with a location of the object, wherein the light sensor location is correlated with at least one single pixel of the pixilated light-turning layer;

determining a position of a touch event based on mapping the light sensor location with the location of the object;

receiving light directed from the pixilated light-turning layer at a second light sensor location;

mapping the second light sensor location with a location of a second object above the light guide, wherein the second light sensor location is correlated with a pixel of the pixilated light-turning layer that is not correlated with the first light sensor location; and

determining a position of another touch event based on mapping the second light sensor location with the location of the second object, wherein the touch event and the other touch event are simultaneous.

2. The method of claim 1, wherein mapping the light sensor location comprises performing a one-to-one mapping of the light sensor location to a correlated pixel of the pixilated light-turning layer.

3. The method of claim 1, wherein receiving comprises receiving light directed from a holographic layer.

4. The method of claim 1, further comprising causing a plurality of light sources to sequentially emit collimated light into the light guide, wherein mapping the light sensor location includes determining which light source of the plurality of light sources emitted light scattered by the object.

5. The method of claim 1, wherein the received light is directed from the pixilated light-turning layer to the light sensor location via another light guide spaced apart from the light guide.