Optical touchpad system and waveguide for use therein

• US 20080007540A1
• Filed: 07/06/2006
• Published: 01/10/2008
• Est. Priority Date: 07/06/2006
• Status: Active Grant

• Current Assignee: FlatFrog Laboratories AB
• Original Assignee: O-Pen A/S
• Inventors: Ostergaard, Jens Wagenblast Stubbe
• Granted Patent: US 8,031,186 B2
• Time in Patent Office: Days
• US Class Current: 345/176
• CPC Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

An optical touchpad system is disclosed that may be easily integrated into a variety of applications. One feature of the optical touchpad system that may contribute to this versatility may be the ability of the optical touchpad system to function in the same manner independent from a topology and/or opacity of an interface surface of the optical touchpad system. This may enable the interface surface to be composed of any of a variety of materials. This may further enable the interface surface to include various topologies adapted for the application in which the optical touchpad system may be employed.

Claims

1. An optical touchpad system comprising:

one or more emitters configured to emit electromagnetic radiation;

one or more sensors configured to receive electromagnetic radiation and output one or more output signals that correspond to one or more properties of the received electromagnetic radiation;

a waveguide that guides a portion of the electromagnetic radiation emitted by the emitters to the sensors, the waveguide comprising;

an irradiation layer that is optically coupled to the one or more emitters to receive electromagnetic radiation emitted therefrom, the irradiation layer being disposed within the waveguide such that the electromagnetic radiation received by the irradiation layer from the one or more emitters is trapped within the irradiation layer at least in part by total internal reflection;

an interface surface spaced apart from the irradiation layer, the interface surface being configured to be engaged by a user with an object; and

a signal layer separate from the irradiation layer that is optically coupled to the one or more sensors;

wherein the waveguide is configured such that if the interface surface is engaged with the object, the engagement therebetween causes the irradiation layer to deform such that a portion of the electromagnetic radiation trapped within the irradiation layer is leaked from the irradiation layer and guided to the one or more sensors at least in part by the signal layer.

2. The optical touchpad system of claim 1, further comprising one or more processors operatively coupled to the one or more sensors to receive the one or more output signals generated by the sensors, wherein the one or more processors determine the position on the interface surface of the engagement between the object and the interface layer based on the one or more output signals generated by the one or more sensors.

3. The optical touchpad system of claim 1, wherein the irradiation layer is bounded on one side by a first surface that is generally planar and on a side opposite the first surface by a second surface that is generally planar and generally parallel to the first surface, and wherein the electromagnetic radiation trapped within the irradiation layer at least in part by total internal reflection is reflected at the first surface and totally internally reflected at or near a total internal reflection mirror formed at the second surface.

4. The optical touchpad system of claim 3, wherein the electromagnetic radiation reflected at the first surface is reflected by a total internal reflection mirror formed at or near the first surface.

5. The optical touchpad system of claim 3, wherein the deformation of the irradiation layer comprises a deformation of the first surface such that at least a portion of the electromagnetic radiation reflected by the first surface at the deformation of the first surface is deflected out of the irradiation layer and into the signal layer.

6. The optical touchpad system of claim 1, wherein the irradiation layer has a first index of refraction and the signal layer has a second index of refraction that is lower than the first index of refraction.

7. The optical touchpad system of claim 6, wherein the signal layer is formed directly adjacent to the irradiation layer such that the boundary between the signal layer and the irradiation layer forms a total internal reflection mirror.

8. The optical touchpad system of claim 1, further comprising an interface layer that is bounded on one side by the interface surface, wherein at least a first portion of the interface layer at the interface surface is substantially opaque and at least a second portion of the interface layer at the interface surface is substantially transparent.

9. The optical touchpad system of claim 1, further comprising an interface layer that is bounded on one side by the interface surface and on a side opposite from the interface surface by the irradiation layer.

10. The optical touchpad system of claim 1, wherein the interface surface has topologically irregular features.

11. The optical touchpad system of claim 10, wherein the topographically irregular features comprise one or more of a key, a button, or a joystick.

12. The optical touchpad system of claim 10, wherein topologically irregular features comprise one or more topological features selectively positioned on the interface surface by a user to customize the interface surface.

13. A waveguide configured to receive electromagnetic radiation from one or more emitters and guides a portion of the received electromagnetic radiation to one or more sensors, the waveguide comprising:

a irradiation layer configured to be optically coupled to the one or more emitters to receive electromagnetic radiation emitted therefrom, the irradiation layer being disposed within the waveguide such that the electromagnetic radiation received by the irradiation layer from the one or more emitters is trapped within the irradiation layer at least in part by total internal reflection;

an interface surface spaced apart from the irradiation layer, the interface surface being configured to be engaged by a user with an object; and

a signal layer separate from the irradiation layer configured to be optically coupled to the one or more sensors;

wherein the waveguide is configured such that if the interface surface is engaged with the object and if there is electromagnetic radiation trapped within the irradiation layer at least in part by total internal reflection, the engagement between the object and the interface surface causes the irradiation layer to deform such that a portion of the electromagnetic radiation trapped at least in part by total internal reflection within the irradiation layer is (i) leaked from the irradiation layer and (ii) guided to the one or more sensors by the signal layer.

14. The waveguide of claim 13, wherein the irradiation layer is bounded on one side by a first surface that is generally planar and on a side opposite the first surface by a second surface that is generally planar and generally parallel to the first surface, and wherein the electromagnetic radiation trapped within the irradiation layer at least in part by total internal reflection is reflected at the first surface and totally internally reflected at or near a total internal reflection mirror formed at the second surface.

15. The waveguide of claim 14, wherein the electromagnetic radiation reflected at the first surface is reflected by a total internal reflection mirror formed at or near the first surface.

16. The waveguide of claim 14, wherein the deformation of the irradiation layer comprises a deformation of the first surface such that at least a portion of the electromagnetic radiation reflected by the first surface at the deformation of the first surface is deflected out of the irradiation layer and into the signal layer.

17. The waveguide of claim 13, wherein the irradiation layer has a first index of refraction and the signal layer has a second index of refraction that is lower than the first index of refraction.

18. The waveguide of claim 17, wherein the signal layer is formed directly adjacent to the irradiation layer such that the boundary between the signal layer and the irradiation layer forms a total internal reflection mirror.

19. The waveguide of claim 13, further comprising an interface layer that is bounded on one side by the interface surface, wherein the interface layer is substantially opaque.

20. The waveguide of claim 13, further comprising an interface layer that is bounded on one side by the interface surface and on a side opposite from the interface surface by the irradiation layer.

21. The waveguide of claim 13, wherein the interface surface has topologically irregular features.

22. The waveguide of claim 21, wherein the topographically irregular features comprise one or more of a key, a button, or a joystick.

23. The waveguide of claim 21, wherein topologically irregular features comprise one or more topological features selectively positioned on the interface surface by a user to customize the interface surface.