Edge-coupled touch-sensitive apparatus

• US 10,268,319 B2
• Filed: 12/17/2013
• Issued: 04/23/2019
• Est. Priority Date: 12/17/2012
• Status: Active Grant

• Current Assignee: FlatFrog Laboratories AB
• Original Assignee: FlatFrog Laboratories AB
• Inventors: Wassvik, Ola, Bergstrom, Hakan, Fagrenius, Gustav
• Primary Examiner(s): Chang, Kent W
• Assistant Examiner(s): Shah, Sujit
• Application Number:
  US14/652,736
• Publication Number:
  US 20150331547A1
• Time in Patent Office: 1,953 Days
• Field of Search: 345173-179
• CPC Class Codes: G06F 1/16 Constructional details or arrangements
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• 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 3/042 by opto-electronic means
• 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

A touch-sensitive apparatus includes a light-transmissive panel having a front surface, an opposite rear surface, and a side edge connecting the front and rear surfaces, and a light-transmissive sheet laminated over the front surface of the light-transmissive panel. The light-transmissive sheet has a portion extending beyond the side edge of the light-transmissive panel to cover a light emitter and detector. The touch-sensitive apparatus further includes a shielding element on a lower surface of the light-transmissive sheet, the shielding element covering at least said light emitter and detector, and the shielding element blocking light having a wavelength range in which the light emitter outputs light. The lower surface of the light-transmissive sheet is in optical contact with the front surface of the light-transmissive panel.

Claims

1. A touch-sensitive apparatus, comprising:

a light-transmissive panel having a front surface, an opposite rear surface, and a first side edge and a second side edge connecting the front surface and the rear surface;

a light emitter positioned on a first support structure, said light emitter configured to input light at a first side edge portion, wherein the first support structure is separate from the light-transmissive panel;

a detector positioned on a second support structure, said detector configured to receive light output through a second side edge portion;

a light-transmissive sheet laminated over the front surface of the light-transmissive panel, the light-transmissive sheet having a first portion extending beyond the first side edge of the light-transmissive panel, the first portion configured to cover the light emitter and a second portion extending beyond the second side edge of the light transmissive panel, the second portion configured to cover the detector;

a shielding element positioned between the first support structure and a lower surface of the light-transmissive sheet, the shielding element covering said light emitter, and the shielding element configured to block light having a wavelength range in which the light emitter outputs light;

wherein the lower surface of the light-transmissive sheet is in optical contact with the front surface of the light-transmissive panel, so as to allow input light to propagate between the light emitter and the detector through the light-transmissive panel and the light-transmissive sheet via total internal reflection between an upper surface of the light-transmissive sheet and the rear surface of the light-transmissive panel;

wherein at least a first reflection of the input light at the upper surface of the light-transmissive sheet and a second reflection at the rear surface of the light-transmissive panel are at critical angles resulting in total internal reflection of the input light between at least the first reflection and the second reflection; and

wherein the first reflection and the second reflection are consecutive reflections of the input light.

2. The touch-sensitive apparatus of claim 1,

wherein the first support structure is secured towards the lower surface of the light-transmissive sheet.

3. The touch-sensitive apparatus of claim 1,

wherein the first support structure is secured towards the rear surface of the light-transmissive panel.

4. The touch-sensitive apparatus of claim 2, wherein said support structure is a printed circuit board.

5. The touch-sensitive apparatus of claim 2, wherein said support structure is a flex film.

6. The touch-sensitive apparatus of claim 2, wherein said support structure is an elongate strip along an extended portion of the side edge, and configured to support at least one of a plurality of emitters or a plurality of detectors.

7. The touch-sensitive apparatus of claim 1, further comprising:

a side connecting element configured to secure at least one of said light emitter and said detector towards the side edge of the light-transmissive panel.

8. The touch-sensitive apparatus of claim 7, wherein said side connecting element includes a transparent adhesive or silicon, and said side connecting element is configured to provide optical matching to the light-transmissive panel.

9. The touch-sensitive apparatus of claim 1, wherein the shielding element is a rigid metal sheet member configured to reinforce the portion of the light-transmissive sheet extending beyond the side edge of the light-transmissive panel.

10. The touch-sensitive apparatus of claim 1, wherein the shielding element covers an outer region of the front surface to suppress ambient light incident on the upper surface, within a wavelength range of use, from specularly reaching at least said detector.

11. The touch-sensitive apparatus of claim 1, wherein the shielding element is non-transmissive to visible light.

12. The touch-sensitive apparatus of claim 1, wherein a lower surface of the shielding element, which faces an outer region of the front surface of the light-transmissive panel, is specularly reflective within a wavelength range of use.

13. The touch-sensitive apparatus of claim 2, wherein said support structure is attached to a lower surface of the shielding element.

14. The touch-sensitive apparatus of claim 1, wherein the light-transmissive sheet includes a rigid layer.

15. The touch-sensitive apparatus of claim 14, wherein the rigid layer is composed of the same material as the light-transmissive panel.

16. The touch-sensitive apparatus of claim 1, further comprising:

a light coupling member arranged at the side edge, and configured to optically connect at least one of the light emitter and the detector to the light-transmissive panel.

17. The touch-sensitive apparatus of claim 16, wherein the light coupling member includes at least one non-imaging, diffusively transmitting optical element arranged on the side edge of the light-transmissive panel;

the light emitter is configured to emit a beam of light onto the at least one non-imaging, diffusively transmitting optical element; and

the detector is configured to receive detection light generated by diffuse transmission as propagating light from within the light-transmissive panel impinges on the at least one non-imaging, diffusively transmitting optical element.

18. The touch-sensitive apparatus of claim 1, wherein the light-transmissive panel is thicker than the light-transmissive sheet.

19. The touch-sensitive apparatus of claim 1, wherein the light-transmissive panel overlays a display.