Optical proximity sensor with improved shield and lenses

• US 8,232,883 B2
• Filed: 12/04/2009
• Issued: 07/31/2012
• Est. Priority Date: 12/04/2009
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Yao, Yufeng, Ong, Chi Boon, Ong, Sze Ping
• Primary Examiner(s): Bugg, George
• Assistant Examiner(s): McNally, Kerri
• Application Number:
  US12/631,793
• Publication Number:
  US 20110133941A1
• Time in Patent Office: 970 Days
• Field of Search: 340/600
• US Class Current: 340/600
• CPC Class Codes: G01J 1/02 Details
• CPC Class Codes: G01J 1/0214 Constructional arrangements for removing stray light
• CPC Class Codes: G01J 1/0271 Housings; Attachments or accessories for photometers
• CPC Class Codes: H03K 17/945 Proximity switches H03K17/96 takes precedence

Abstract

Various embodiments of an optical sensor comprising a novel shield that may be quickly and accurately aligned and positioned with respect to an underlying light emitting and light detecting assembly are disclosed. Also disclosed are novel lens arrangements for efficiently collimating light emitted and received by the optical proximity sensor, and for reducing crosstalk.

Claims

1. An optical proximity sensor, comprising:

an infrared light emitter mounted on a substrate;

an infrared light detector mounted on the substrate;

an integrated circuit mounted on the substrate and comprising light emitter driving and light detecting circuits operably connected to the light emitter and the light detector, respectively;

a first spherical lens disposed over the light emitter and configured to collect and direct light emitted by the light emitter in an upward direction towards an object to be detected;

a second spherical lens disposed over the light detector and configured to collect and direct light incident thereon that has been transmitted upwardly by the first lens and reflected downwardly from the object to be detected towards the light detector, and

a light shield disposed over the light emitter, the light detector, the first lens and the second lens, the light shield comprising first and second top portions, a light barrier projecting downwardly between the first and second top portions to separate the light emitter from the light detector and divide the proximity sensor into light emitting and light detecting portions, at least one light shield alignment and spacing member projecting downwardly from either the first portion or the second portion, and first and second apertures disposed through the first and second portions over the first and second lenses, respectively;

wherein alignment of the shield over the proximity sensor is optimized by the light barrier and the at least one light shield alignment and spacing member, crosstalk between the light emitter and the light detector is minimized, and detection distance of the proximity sensor is maximized by the configurations of the light emitter, the first lens, the light detector, the second lens, and the shield respecting one another.

2. The optical proximity sensor of claim 1, further comprising an ambient light sensor disposed in the light detecting portion.

3. The optical proximity sensor of claim 2, wherein the ambient light sensor is operably connected to a control circuit for a display, a keypad or a touchscreen in a portable electronic device.

4. The optical proximity sensor of claim 3, wherein the control circuit modulates a functionality of the display, keypad or touchscreen in accordance with ambient light illumination levels detected by the ambient light sensor.

5. The proximity sensor of claim 4, wherein the functionality is one of brightness, illumination, and on/off.

6. The optical proximity sensor of claim 3, wherein the ambient light sensor is configured to detect the presence of an object in proximity thereto and the control circuit modulates the functionality of the display, keypad or touchscreen in accordance with the detected presence of the object.

7. The optical proximity sensor of claim 3, wherein a third spherical lens is disposed over the ambient light sensor and a third aperture is disposed through the second portion of the shield over the ambient light sensor.

8. The optical proximity sensor of claim 1, wherein the proximity sensor is configured to detect the object to be detected at distances exceeding about 50 mm.

9. The optical proximity sensor of claim 1, wherein the proximity sensor is configured to detect the object to be detected at distances exceeding about 75 mm.

10. The optical proximity sensor of claim 1, wherein the proximity sensor is configured to detect the object to be detected at distances exceeding about 100 mm.

11. The optical proximity sensor of claim 1, wherein the at least one light shield alignment and spacing member forms one or a plurality of downwardly-projecting grooves, v- or u-shaped grooves, channels, v- or u-shaped channels, rays, ridges, standoffs or nubbins.

12. The optical proximity sensor of claim 1, wherein at least one of the light emitter and the light detector is a semiconductor die.

13. The optical proximity sensor of claim 1, wherein the integrated circuit is an application specific integrated circuit (“

ASIC”

).

14. The optical proximity sensor of claim 1, wherein the optical proximity sensor is incorporated into a portable electronic device.

15. The optical proximity sensor of claim 14, wherein the portable electronic device is a smart phone, a mobile telephone, a personal data assistant (PDA), a laptop computer, a notebook computer, or a computer.

16. The optical proximity sensor of claim 14, wherein an optically transmissive window is disposed above the proximity sensor.

17. The optical proximity sensor of claim 14, wherein a gap between the optically transmissive window and the proximity sensor is less than or equal to 1 mm.

18. The optical proximity sensor of claim 14, wherein a gap between the optically transmissive window and the proximity sensor is less than or equal to 0.5 mm.

19. The optical proximity sensor of claim 1, wherein at least one of the first and second lenses is molded from an optically transmissive material.

20. The optical proximity sensor of claim 1, wherein a distance between a first center of the first lens and a second center of the second lens ranges between about 2.0 mm and about 3.0 mm.

21. The optical proximity sensor of claim 1, wherein the sensor has a height of about 1 mm.

22. The optical proximity sensor of claim 1, wherein the top surface of the shield is located above uppermost portions of the first and second lenses.

23. A method of making an optical proximity sensor, comprising:

mounting an infrared light emitter on a substrate;

mounting an infrared light detector on the substrate;

mounting an integrated circuit comprising light emitter driving and light detecting circuits on the substrate and operably connecting the circuits to the light emitter and the light detector;

placing or forming a first spherical lens over the light emitter, the first lens being configured to collect and direct light emitted by the light emitter in an upward direction towards an object to be detected;

placing or forming a second spherical lens over the light emitter, the second lens being configured to collect and direct light incident thereon that has been transmitted upwardly by the first lens and reflected downwardly from the object to be detected towards the light detector, and

disposing a light shield over the light emitter, the light detector, the first lens and the second lens, the light shield comprising first and second top portions, a light barrier projecting downwardly between the first and second top portions to separate the light emitter from the light detector and divide the proximity sensor into light emitting and light detecting portions, at least one light shield alignment and spacing member projecting downwardly from either the first top portion or the second top portion, and first and second apertures disposed through the shield over the first and second lenses, respectively;

wherein alignment of the shield over the proximity sensor is optimized by the light barrier and the at least one light shield alignment and spacing member, crosstalk between the light emitter and the light detector is minimized, and detection distance of the proximity sensor is maximized, by the configurations of the light emitter, the first lens, the light detector, the second lens, and the shield respecting one another.

24. The method of claim 23, further comprising incorporating the proximity sensor into a portable electronic device.

25. The method of claim 24, wherein the portable electronic device is a smart phone, a mobile telephone, a personal data assistant (PDA), a laptop computer, a notebook computer, or a computer.