Proximity sensor arrangement having an optical barrier to pass light to a photo detector via a cover

• US 9,733,343 B2
• Filed: 11/06/2013
• Issued: 08/15/2017
• Est. Priority Date: 11/27/2012
• Status: Active Grant

• Current Assignee: ams AG (Ams-Osram AG)
• Original Assignee: ams AG (Ams-Osram AG)
• Inventors: Mehrl, David
• Primary Examiner(s): Le, Que T
• Application Number:
  US14/647,423
• Publication Number:
  US 20150323653A1
• Time in Patent Office: 1,378 Days
• Field of Search: 250221, 250216, 250239, 250551, 2502141, 34053923, 340555-557
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 17/32 using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/4814 of transmitters alone
• CPC Class Codes: G01V 8/12 using one transmitter and one receiver
• CPC Class Codes: H03K 17/941 using an optical detector H03K17/968 takes precedence
• CPC Class Codes: H03K 2217/94108 making use of reflection

Abstract

A proximity sensor arrangement comprises an optical barrier being placed between a light emitting device and a photo-detector. The light emitting device, the photo-detector and the optical barrier are covered by a cover. The optical barrier is being designed to block light emitted from the light emitting device to the photo-detector and reflected by the cover by means of specular reflection. Furthermore, the optical barrier is being designed to pass the light emitted from the light emitting device to the photo-detector via the cover and scattered on or above a first surface of the cover facing away from the light emitting device and the photo-detector.

Claims

1. A proximity sensor arrangement, comprising an optical barrier being placed between a light emitting device and a photo-detector, wherein

the light emitting device, the photo-detector and the optical barrier are covered by a cover;

the optical barrier is configured to block light emitted from the light emitting device to the photo-detector and reflected by the cover by means of specular reflection;

the optical barrier is configured to pass the light emitted from the light emitting device to the photo-detector via the cover and scattered on or above a first surface of the cover facing away from the light emitting device and the photo-detector, and

the optical barrier is configured narrow enough to frustrate specular reflection paths from the light emitting device to the photo-detector via the cover surfaces, while permitting rays to pass around the barrier by indirect or diffusely scattered paths via diffusive scattering on or above the first surface of the cover.

2. The proximity sensor arrangement of claim 1, wherein

the optical barrier extends along a first principal axis being essentially parallel to the first surface of the cover;

and

the extent along the first principal axis is arranged such that light scattered on or above the first surface of the cover is permitted to pass around the optical barrier to reach the photo-detector.

3. The proximity sensor arrangement of claim 1, wherein

the light emitting device emits light, in particular infrared light, into an emission cone;

and

the optical barrier is configured to intersect the emission cone such that essentially no light reaches the photo-detector by way of specular reflection via the cover and/or by means of direct emission.

4. The proximity sensor arrangement of claim 3, wherein the optical barrier extends along its first principal axis at least as much to block the emission cone emitted by the light emitting device.

5. The proximity sensor arrangement of claim 1, wherein the optical barrier comprises a three-dimensional column-shaped body.

6. The proximity sensor arrangement of claim 1, wherein

the light emitting device, the photo-detector and the optical barrier are positioned within a first plane;

and

the optical barrier extends at least along a second axis being orthogonal with respect to the first plane and directed towards the cover.

7. The proximity sensor arrangement of claim 6, wherein the column shaped body comprises a flared profile, in particular a flared base by which the column shaped body is mounted onto the first plane.

8. The proximity sensor arrangement of claim 6, wherein the first plane comprises a printed circuit board.

9. The proximity sensor arrangement of claim 2, wherein

the optical barrier comprises an essentially two-dimensional aperture arrangement, in particular extending along the first and along a third principal axis;

and

the aperture arrangement is essentially parallel to a second surface of the cover.

10. The proximity sensor arrangement of claim 9, wherein

the second plane comprises the second surface of the cover facing towards the light emitting device and the photo-detector;

and

the aperture arrangement at least partly covers the second surface.

11. The proximity sensor arrangement of claim 9, wherein the aperture arrangement comprises an opaque material, in particular an ink.

12. The proximity sensor arrangement of claim 9, wherein the aperture arrangement comprises

at least one aperture being transmissive to the light emitted by the light emitting device;

and

a mask being essentially opaque to the light emitted by the light emitting device.

13. The proximity sensor arrangement of claim 1, wherein the light emitting device comprises a light emitting diode, an infrared light emitting diode or a laser.

14. The proximity sensor arrangement of claim 1, wherein the photo-detector comprises a photo-diode, a charge coupled device, or a complementary metal-oxide semiconductor.