LIGHT PIPE ARRAY LENS, OPTICAL FINGER NAVIGATION DEVICE WITH THE LENS AND METHOD FOR MAKING THE DEVICE

• US 20100128003A1
• Filed: 11/26/2008
• Published: 05/27/2010
• Est. Priority Date: 11/26/2008
• Status: Active Grant

• Current Assignee: PixArt Imaging Incorporated
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Orsley, Timothy James
• Granted Patent: US 8,847,915 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: B29D 11/00663 Production of light guides
• CPC Class Codes: G02B 6/08 with fibre bundle in form of plate
• CPC Class Codes: G06F 3/0317 in co-operation with a patterned surface, e.g. absolute position or relative movement detection for an optical mouse or pen positioned with respect to a coded surface
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface

Abstract

An optical finger navigation device and method for making the device uses a light pipe array lens, which includes an array of light pipes formed in a monolithic block of material. The light pipe array lens is configured to function similarly to a fiber bundle lens to transmit light through the lens using the light pipes in the monolithic block of material.

Claims

1. A light pipe array lens comprising:

a monolithic block having first and second surfaces; and

a two-dimensional array of light pipes disposed in the monolithic block such that the light pipes extend from the first surface to the second surface, the light pipes being made of a first material, each of the light pipes being enclosed by a second material having an index of refraction lower than an index of refraction of the first material.

2. The light pipe array lens of claim 1, wherein the monolithic block is made of the second material.

3. The light pipe array lens of claim 1, further comprising walls made of the second material that are disposed in the monolithic block such that each of the light pipes is defined and enclosed by the walls.

4. The light pipe array lens of claim 1, wherein the first material includes polymer with nanoparticles.

5. The light pipe array lens of claim 1, wherein the second material includes optical epoxy.

6. The light pipe array lens of claim 1, wherein the light pipes are disposed at an angle of approximately forty-five degrees from the bottom surface of the monolithic block.

7. An optical finger navigation device comprising:

a light source configured to emit light;

a light pipe array lens positioned to receive the light reflected from a navigation surface, the light pipe array lens comprising;

a monolithic block having first and second surfaces; and

a two-dimensional array of light pipes disposed in the monolithic block such that the light pipes extend from the first surface to the second surface, the light pipes being made of a first material, each of the light pipes being enclosed by a second material having an index of refraction lower than an index of refraction of the first material; and

an image sensor array positioned to receive the light from the light pipe array lens to capture image frames of the navigation surface, the image frames providing displacement information of the navigation surface relative to the optical navigation system.

8. The optical finger navigation device of claim 7, wherein the monolithic block of the light pipe array lens is made of the second material.

9. The optical finger navigation device of claim 7, wherein the light pipe array lens further comprises walls made of the second material that are disposed in the monolithic block such that each of the light pipes is defined and enclosed by the walls.

10. The optical finger navigation device of claim 7, wherein the first material includes polymer with nanoparticles.

11. The optical finger navigation device of claim 7, wherein the second material includes optical epoxy.

12. The optical finger navigation device of claim 7, wherein the light pipes of the light pipe array lens are disposed at an angle of approximately forty-five degrees from the bottom surface of the monolithic block.

13. The optical finger navigation device of claim 7, wherein the image sensor array is part of a navigation senor, the navigation sensor including a navigation engine configured to estimate relative displacement of the navigation surface using the image frames of the navigation surface from the image sensor array.

14. The optical finger navigation device of claim 13, further comprising a printed circuit board, the light source and the navigation sensor being mounted on the printed circuit board.

15. A method of making an optical finger navigation device, the method comprising:

fabricating a light pipe array lens that includes an array of light pipes in a monolithic block of material, the light pipes being made of a first material, each of the light pipes being enclosed by a second material having an index of refraction lower than an index of refraction of the first material;

attaching the light pipe array lens to a navigation sensor having an image sensor array;

mounting the navigation sensor with the light pipe array lens onto a substrate; and

mounting a light source onto the substrate.

16. The method of claim 15, wherein the monolithic block of the light pipe array lens is made of the second material.

17. The method of claim 16, wherein the fabricating the light pipe array lens includes forming microchannels in the monolithic block and filling the microchannels with the first material.

18. The method of claim 15, wherein the fabricating the light pipe array includes forming walls in the monolithic block such that each of the light pipes is defined and enclosed by the walls, the walls being made of the second material.

19. The method of claim 18, wherein the forming the walls includes making vertical and horizontal cuts in the monolithic block and filling vertical and horizontal spaces formed by the vertical and horizontal cuts with the second material.

20. The method of claim 15, wherein the fabricating the light pipe array lens includes forming the light pipes in the monolithic block at an angle of approximately forty-five degrees from the bottom surface of the monolithic block.