Apparatus and method for detecting surface shear force on a display device

Patent metadata

Field	Value
Publication number	US-10114510-B2
Application number	US-201414562627-A
Country	US
Kind code	B2
Filing date	Dec 5, 2014
Priority date	Dec 23, 2013
Publication date	Oct 30, 2018
Grant date	Oct 30, 2018

Abstract

A display device includes: an optical sensing array to detect light; a backlight to emit light toward a surface of the display device; and a thin optical film layer at the surface of the display device, the thin optical film layer being configured to, while a first shear force is being applied at a first point of contact at the surface of the display device, reflect light having a first wavelength at a front area ahead of the first point of contact in a direction of the first shear force, and reflect light having a second wavelength at a back area behind the first point of contact opposite the front area, the first wavelength being different from the second wavelength.

First claim

What is claimed is:

1. A display device comprising:
an optical sensing array to detect light;
a backlight to emit light toward a surface of the display device; and
a thin optical film layer at the surface of the display device, the thin optical film layer being configured to, while a first shear force is being applied at a first point of contact at the surface of the display device, reflect light having a first wavelength at a front area ahead of the first point of contact in a direction of the first shear force, and reflect light having a second wavelength at a back area behind the first point of contact opposite the front area, the first wavelength being different from the second wavelength, wherein a total reflection spectrum reflected by the front area is distinct from a total reflection spectrum reflected by the back area while the first shear force is being applied at the first point of contact.

2. The display device of claim 1 , wherein the first and second wavelengths are spectral distributions corresponding to different bands of infrared light.

3. The display device of claim 1 , wherein the thin optical film layer comprises a deformable surface adapted to thicken in the direction of the first shear force and thin in a direction opposite the direction of the first shear force.

4. The display device of claim 3 , wherein the first wavelength is greater than the second wavelength.

5. The display device of claim 1 , wherein the thin optical film layer comprises a photonic crystal layer adapted to compress in the direction of the first shear force and stretch in a direction opposite the direction of the first shear force.

6. The display device of claim 5 , wherein the first wavelength is less than the second wavelength.

7. The display device of claim 5 , wherein the first wavelength greater than the second wavelength.

8. The display device of claim 5 , wherein the photonic crystal layer comprises a polymer with embedded voids.

9. The display device of claim 5 , wherein the photonic crystal layer comprises polymer-based opals.

10. The display device of claim 1 , wherein the display device is configured to measure the first shear force at the first point of contact concurrently with a second shear force at a second point of contact by detecting a first spectral shift of light reflected from the thin optical film layer at the first point of contact and a second spectral shift of light reflected from the thin optical film layer at the second point of contact.

11. A method for sensing a shear force at a surface of a display device comprising an optical sensing array to detect light, a backlight to emit light toward a surface of the display device, and a thin optical film layer at the surface of the display device, the method comprising:
detecting a first point of contact at the surface of the display device;
reflecting by the thin optical film layer, while a first shear force is being applied at the first point of contact at the surface of the display device, light having a first wavelength at a front area ahead of the first point of contact in a direction of the first shear force;
reflecting by the thin optical film layer, while the first shear force is being applied, light having a second wavelength at a back area behind the first point of contact opposite the front area, the second wavelength being different from the first wavelength, wherein a total reflection spectrum reflected by the front area is distinct from a total reflection spectrum reflected by the back area while the first shear force is being applied at the first point of contact; and
sensing by the optical sensing array the reflected light having the first and second wavelengths.

12. The method of claim 11 , wherein the first and second wavelengths are wavelengths corresponding to infrared light.

13. The method of claim 12 , wherein the first wavelength is greater than the second wavelength.

14. The method of claim 11 , wherein the thin optical film layer comprises a deformable surface adapted to thicken in the direction of the first shear force and thin in a direction opposite the direction of the first shear force, and an anti-reflective film on the deformable surface.

15. The method of claim 11 , wherein the thin optical film layer comprises a photonic crystal layer adapted to compress in the direction of the first shear force and stretch in a direction opposite the direction of the first shear force.

16. The method of claim 15 , wherein the photonic crystal layer comprises a polymer with embedded voids.

17. The method of claim 15 , wherein the photonic crystal layer comprises polymer-based opals.

18. The method of claim 11 , wherein the method further comprises:
measuring the first shear force at the first point of contact concurrently with a second shear force at a second point of contact by detecting a first spectral shift of light reflected from the thin optical film layer at the first point of contact and a second spectral shift of light reflected from the thin optical film layer at the second point of contact.

Assignees

• Samsung Display Co Ltd

Inventors

• Hoffman David M
• Galela Jennifer J
• Xue Jiuzhi

Classifications

• G06F3/042 Primary

  by opto-electronic means · CPC title

• G06F3/0421 Primary

  by interrupting or reflecting a light beam, e.g. optical touch-screen · CPC title