Touch screen systems and methods for sensing touch screen displacement

• US 9,619,084 B2
• Filed: 09/30/2013
• Issued: 04/11/2017
• Est. Priority Date: 10/04/2012
• Status: Active Grant

• Current Assignee: Corning Incorporated
• Original Assignee: Corning Incorporated
• Inventors: Deichmann, Oberon Denaci, Miller, William James, Nolan, Daniel Aloysius, Yeary, Lucas Wayne
• Primary Examiner(s): Davis, Tony
• Application Number:
  US14/041,426
• Publication Number:
  US 20140098065A1
• Time in Patent Office: 1,289 Days
• Field of Search: 345173-175
• CPC Class Codes: G06F 3/0414 using force sensing means to determine a position
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

A touch screen system configured to detect a displacement of a cover sheet when pressure or force is applied to the cover sheet upper surface. A light source and photodetector are configured to be in optical communication by reflection of light from the light source from the lower surface of the cover sheet. A displacement of the coversheet changes the amount of reflected light that falls upon the detector. The detector signal can be used to measure the amount of displacement, as well as the time-evolution of the displacement. The touch-screen system can be interfaced with a touch-sensitive display unit to form a display system having both pressure-sensing capability and touch-sensing capability.

Claims

1. A touch screen system for sensing a touch event, comprising:

a cover screen having an upper surface, a lower surface and a perimeter;

a support frame having a central aperture and stood off from the cover screen by at least one resilient stand-off member;

a photodetector disposed adjacent the lower surface of and external to the cover screen,

wherein the photodetector and the lower surface of the cover screen are separated by a distance δ

z and define a Fabry-Perot cavity that resides outside of the cover screen and that has a transmission defined by the distance δ

z;

a light source that emits light and that is in optical communication with the photodetector via reflection off of a portion of the cover screen lower surface adjacent the perimeter and without the light or the reflected light traveling through or above the cover screen,

such that when the cover screen a is displaced toward the support frame by compressing the at least one stand-off member, the amount of reflected light detected by the photodetector changes; and

wherein the transmission of the Fabry-Perot cavity changes by changing the distance δ

z when the cover screen is displaced towards or away from the photodetector, thereby causing the change in the amount of light detected by the photodetector,

wherein each light source and photodetector defines a sensor head,

wherein the system includes multiple sensor heads operably arranged adjacent the cover sheet screen perimeter and adjacent the lower surface,

with the multiple sensor heads operably connected to a microcontroller,

wherein the signal output from the multiple sensor heads is exported to a computer and used to determine the position and associated force of the touch event,

further comprising a capacitive or resistive based system to determine the position of two or more simultaneous touch events,

wherein the signal output from the multiple sensor heads is exported to a computer and used to determine the associated force of the two or more simultaneous touch events.

2. The touch screen system of claim 1, further comprising a microcontroller operably connected to the light source and the photodetector and configured to receive a detector signal from the photodetector and determine from tile detector signal an amount of displacement of the cover screen.

3. The touch screen system of claim 1, further comprising a partially reflecting member disposed immediately adjacent the photodetector surface to further define the Fabry-Perot cavity.

4. The touch screen system of claim 1, further including a cover adjacent the perimeter and on at least one of the upper and lower surfaces, the cover being configured to block at least a visible wavelength of light.

5. The touch screen system of claim 1, wherein the portion of the cover screen lower surface adjacent the perimeter from which light from the laser reflects includes a reflection coating.

6. The touch screen system of claim 1, wherein the light from the light source has an infrared wavelength.

7. The touch screen system of claim 1, wherein the cover screen is transparent to a visible wavelength of light.

8. The touch screen system of claim 1, wherein the frame is configured to interface with a touch-sensitive display.

9. A display system, comprising:

the touch-screen system according to claim 1; and

a display unit having a display, with the touch-screen operably interfaced therewith.

10. The display system of claim 9, wherein the display unit includes one of capacitive and resistive touch-sensing capability.