RETROREFLECTOR FOR USE IN TOUCH SCREEN APPLICATIONS AND POSITION SENSING SYSTEMS

• US 20090295755A1
• Filed: 01/12/2009
• Published: 12/03/2009
• Est. Priority Date: 01/14/2008
• Status: Active Grant

• Current Assignee: Avery Dennison Corporation, Smart Technologies ULC (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Avery Dennison Corporation
• Inventors: BRIDGER, Simon, CHAPMAN, Steven R.
• Granted Patent: US 8,928,625 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G02B 5/124 plural reflecting elements forming part of a unitary plate or sheet
• 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 screen system and prismatic film includes a retroreflective substrate having a plurality of retroreflective elements having triangular cube corners. A metallized layer is disposed over at least a portion of the retroreflective elements. In one embodiment, the prismatic film includes two colored substrates mounted over the retroreflective elements. In another embodiment, a single substrate is mounted over the retroreflective elements. It is often desired that a color of the substrate(s) be chosen that is highly transparent in the infrared spectrum, but is also non-transparent in the visible light spectrum, giving the prismatic film a dark appearance. The prismatic film includes a plurality of retroreflective elements having triangular cube corners with a cant in a range between about 4 degrees in a face more parallel direction to 18 degrees in an edge more parallel direction and a cube depth between about 0.002 and 0.008 inches or with a cant of about 5.5 to 22 degrees in an edge more parallel direction and a cube depth between about 0.0005 and 0.004 inches, or with a cant of about 8 to 35 degrees in a face more parallel direction and a cube depth between 0.001 and 0.012 inches.

Claims

1. A prismatic film, comprising:

an unpinned prismatic film having a retroreflective substrate including a plurality of triangular cube corner retroreflective elements and a metallized layer disposed over at least a portion of the retroreflective substrate; and

wherein the retroreflective elements have a cant in a range of between about 4 degrees in a face more parallel direction to 18 degrees in an edge more parallel direction and a cube depth between about 0.002 and 0.008 inches.

2. The prismatic film of claim 1, further including a first substrate disposed over at least a portion of the retroreflective substrate, wherein the first substrate has a smooth outer surface.

3. The prismatic film of claim 2, wherein the first substrate has a black dye uniformly distributed throughout.

4. The prismatic film of claim 2, wherein the first substrate has a red dye or a blue dye uniformly distributed throughout.

5. The prismatic film of claim 2, further including a second substrate disposed between the first substrate and the plurality of retroreflective elements

6. A prismatic film comprising:

An unpinned prismatic film having a retroreflective substrate including a plurality of triangular cube corner retroreflective elements and a metallized layer disposed over at least a portion of the retroreflective substrate; and

wherein retroreflective elements have a cant in a range between about 5.5 degrees and 22 degrees in an edge more parallel direction and a cube depth between about 0.0005 and 0.004 inches.

7. The prismatic reflective film of claim 6, including a first substrate disposed over at least a portion of the retroreflective substrate, wherein the first substrate has a smooth outer surface.

8. The prismatic film of claim 7, further including a second substrate disposed between the first substrate and the plurality of retroreflective elements.

9. A prismatic film comprising:

An unpinned prismatic film having a retroreflective substrate including a plurality of triangular cube corner retroreflective elements and a metallized layer disposed over at least a portion of the retroreflective substrate, and

wherein the retroreflective elements have a cant in a range of between about 8 degrees and 35 degrees in a face more parallel direction and a cube depth between 0.001 and 0.012 inches.

10. The prismatic film of claim 9, further including a first substrate disposed over at least a portion of the retroreflective substrate and a second substrate disposed between the first substrate and the plurality of retroreflective elements.

11. A position detection system comprising:

at least one source of electromagnetic radiation for outputting a electromagnetic radiation over at least a portion of a detection area; and

a camera positioned to receive electromagnetic radiation reflected from a prismatic film positioned along a periphery of at least a portion of the detection area, wherein the prismatic film includes a plurality of triangular cube corner retroreflective elements with a cant in a range of between about 4 degrees in a face more parallel direction to 18 degrees in an edge more parallel direction and a cube depth between about 0.002 and 0.008 inches.

12. The system of claim 11, further including a metallized layer disposed over the plurality of retroreflective elements for preventing contaminants and/or moisture from coming in contact with the retroreflective elements and a first substrate positioned between the plurality of retroreflective elements and the source.

13. The system of claim 11, wherein the prismatic film has a double-pass transmission of more than 74% when the source is an infrared source and the prismatic film is substantially opaque when viewed in visible light.

14. The system of claim 11, wherein the detection field is a touch screen display.

15. The system of claim 14, wherein the prismatic film is aligned such that a plane of maximum entrance angularity associated with the prismatic film is substantially parallel to the touch screen.

16. A position detection system comprising:

at least one source of electromagnetic radiation for outputting a electromagnetic radiation over at least a portion of a detection area; and

a camera positioned to receive electromagnetic radiation reflected from a prismatic film positioned along a periphery of at least a portion of the detection area, wherein the prismatic film includes a plurality of triangular cube corner retroreflective elements with a cant in a range of between about 8 degrees and 35 degrees in a face more parallel direction and a cube depth between 0.001 and 0.012 inches.

17. The system of claim 16, further including a metallized layer disposed over the plurality of retroreflective elements for preventing contaminants and/or moisture from coming in contact with the retroreflective elements.

18. The system of claim 16, further including a first substrate disposed over at least a portion of the retroreflective substrate and positioned between the plurality of retroreflective elements and the source.

19. The system of claim 16, wherein the prismatic film has a double-pass transmission of more than 74% when the source is an infrared source and the prismatic film is substantially opaque when viewed in visible light.

20. The system of claim 18, further including a second substrate disposed between the first substrate and the plurality of reflective elements.

21. A position detection system comprising:

at least one source of electromagnetic radiation for outputting a electromagnetic radiation over at least a portion of a detection area; and

a camera positioned to receive electromagnetic radiation reflected from a prismatic film positioned along a periphery of at least a portion of the detection area, wherein the prismatic film includes a plurality of triangular cube corner retroreflective elements with a cant in a range between about 5.5 degrees and 22 degrees in an edge more parallel direction and a cube depth between about 0.0005 and 0.004 inches.

22. The system of claim 21, further including a metallized layer disposed over the plurality of retroreflective elements for preventing contaminants and/or moisture from coming in contact with the reflective elements.

23. The system of claim 21, further including a first substrate disposed over at least a portion of the retroreflective substrate and positioned between the plurality of retroreflective elements and the source and a second substrate disposed between the first substrate and the plurality of retroreflective elements.

24. The system of claim 21, wherein the prismatic film has a double-pass transmission of more than 74% when the source is an infrared source and the prismatic film is substantially opaque when viewed in visible light.