Optical sensors that reduce specular reflections

• US 8,324,602 B2
• Filed: 12/21/2009
• Issued: 12/04/2012
• Est. Priority Date: 04/14/2009
• Status: Active Grant

• Current Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Original Assignee: Intersil Americas LLC (Renesas Electronics Corporation)
• Inventors: Wiese, Lynn K., Kelkar, Nikhil, Patwardhan, Viraj
• Primary Examiner(s): LUU, THANH X
• Application Number:
  US12/643,831
• Publication Number:
  US 20100258710A1
• Time in Patent Office: 1,079 Days
• Field of Search: 250/551, 250/221, 250/239, 257 80- 82, 438/24, 438/25
• US Class Current: 250/551
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/49171 Fan-out arrangements
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01L 31/02325 the optical elements not being integrated nor being directly associated with the device
• CPC Class Codes: H01L 31/173 formed in, or on, a common substrate

Abstract

An optical sensor device, according to an embodiment of the present invention, includes a light source and a light detector. The light source includes one or more light emitting elements, and the light detector includes one or more light detecting elements. A first opaque light barrier portion, between the light source and the light detector, is configured to block light from being transmitted directly from the light source to the light detector. A second opaque light barrier portion, extending from the first opaque light barrier portion in a direction towards the light source, is configured to reduce an amount of specular reflections that would occur if a light transmissive cover plate were placed over the optical sensor device. A third opaque light barrier portion, extending from the first light barrier portion in a direction towards to the light detector, is configured to reduce an amount of specular reflections that would be detected by the light detector, if a light transmissive cover plate were placed over the optical sensor device.

Claims

1. An optical sensor device, comprising:

a light source die including one or more light emitting elements;

a light detector die including one or more light detecting elements;

a first opaque light barrier portion configured to block light from being transmitted directly from the light source die to the light detector die, said first opaque light barrier portion between the light source die and the light detector die;

a light transmissive material covering the light source die and the light detector die; and

a second opaque light barrier portion configured to reduce an amount of specular reflections, if a light transmissive cover plate were placed over the optical sensor device;

said second opaque light barrier portion extending from the first opaque light barrier portion, in a direction towards the light source die, a distance greater than an entire gap between the first opaque light barrier portion and at least one of the one or more light emitting elements of the light source die;

wherein the first opaque light barrier portion separates a portion of the light transmissive material covering the light source die from a portion of the light transmissive material covering the light detector die; and

wherein the second opaque light barrier portion extends over a portion of an outermost surface of the portion of the light transmissive material covering the light source die.

2. The optical sensor device of claim 1, wherein a portion of the second opaque light barrier portion covers at least a portion of at least one of the one or more light emitting elements of the light source die.

3. The optical sensor device of claim 1, wherein:

the first opaque light barrier portion and the second opaque light barrier portion are separately formed;

the first opaque light barrier portion and the second opaque light barrier portion are generally perpendicular to one another; and

a portion of the first opaque light barrier portion is connected by an opaque epoxy to a portion of the second opaque light barrier portion so that light from the light source die does not leak between the first and second opaque light barrier portions.

4. The optical sensor device of claim 1, wherein:

the first opaque light barrier portion separates first and second cavities of the optical sensor device;

the light source die is located within the first cavity;

the light detector die is located within the second cavity; and

the second opaque light barrier portion covers a portion of the first cavity.

5. The optical sensor device of claim 4, wherein the first and second cavities are substantially filled with the light transmissive material that covers the light source die and the light detector die.

6. The optical sensor device of claim 5, wherein the second light barrier portion comprises an opaque material that fills a trench formed in the outermost surface of the portion of the light transmissive material covering the light source die within the first cavity.

7. The optical sensor device of claim 5, wherein the second light barrier portion comprises an opaque material that is deposited on a portion of the outermost surface of the portion of the light transmissive material covering the light source die within the first cavity.

8. The optical sensor device of claim 4, wherein the second light barrier portion comprises a portion of an aperture plate that covers a portion of the outermost surface of the portion of the light transmissive material covering the light source die within the first cavity.

9. The optical sensor device of claim 4, wherein the second light barrier portion comprises a portion of an aperture plate that covers a portion of the first cavity.

10. The optical sensor device of claim 1, wherein the second light barrier portion comprises a portion of an aperture plate.

11. The optical sensor device of claim 1, further comprising a third opaque light barrier portion configured to reduce an amount of specular reflections that would be detected by the one or more light detecting elements of the light detector die, if a light transmissive cover plate were placed over the optical sensor device, said third opaque light barrier portion extending from the first light barrier portion in a direction towards to the light detector die.

12. The optical sensor device of claim 11, wherein a portion of the third opaque light barrier portion covers at least a portion of at least one of the one or more light detecting elements of the light detector die.

13. The optical sensor device of claim 12, wherein:

the first opaque light barrier portion separates first and second cavities of that optical sensor device;

the light source die is located within the first cavity;

the light detector die is located within the second cavity; and

the second opaque light barrier portion covers a portion of the first cavity; and

the third opaque light barrier portion covers a portion of the second cavity.

14. The optical sensor device of claim 13, wherein the second light barrier portion and the third light barrier portion comprise portions of an aperture plate that covers portions of the first and second cavities.

15. The optical sensor device of claim 1, wherein the first opaque light barrier portion and the second opaque light barrier portion are continuously formed from the same material.

16. The optical sensor device of claim 1, further comprising:

a lens covering at least a portion of the light source die and laterally located relative to the second opaque light barrier portion;

wherein the lens is off-centered relative to a center of the one or more light emitting elements of the light source die, such that a center of the lens is offset in a direction away from the first opaque light barrier portion; and

wherein the lens is configured to reduce an amount of specular reflections that would be detected by the light detector die, if a light transmissive cover plate were placed over the optical sensor device.

17. A method for providing an optical sensor device, comprising:

(a) forming first and second cavities that are separated by a first opaque light barrier portion;

(b) attaching a light source die within the first cavity and a light detector die within the second cavity so that the first opaque light barrier portion is between the light detector die and the light source die, wherein the light detector die includes one or more light detecting elements, and the light source die includes one or more light emitting elements; and

(c) covering the light source die and the light detector die with a light transmissive material; and

(d) forming a second opaque light barrier portion that extends from the first opaque light barrier portion, in a direction towards the first cavity, a distance greater than an entire gap between the first opaque light barrier portion and at least one of the one or more light emitting elements of the light source die, such that the second opaque light barrier potion and extends over a portion of an outermost surface of a portion of the light transmissive material covering the light source die,

wherein the second opaque light barrier portion is configured to reduce an amount of specular reflections, if a light transmissive cover plate were placed over the first and second cavities.

18. The method of claim 17, wherein step (c) comprises substantially filling the first and second cavities with the light transmissive material so that the light transmissive material covers the light source die and the light detector die.

19. The method of claim 17, wherein step (d) comprises forming the second opaque light barrier portion by depositing an opaque material in a trench formed in the outermost surface of the portion of the light transmissive material covering the light source die within the first cavity.

20. The method of claim 17, wherein step (d) comprises forming the second opaque light barrier portion by depositing an opaque material on a portion of the outermost surface of the portion of the light transmissive material covering the light source die within the first cavity.

21. The method of claim 17, wherein step (d) comprises forming the second opaque light barrier portion by covering a portion of the outermost surface of the portion of the light transmissive material covering the light source die within the first cavity with a portion of an aperture plate.

22. The method of claim 21, wherein step (d) further comprises using an opaque epoxy to attach a portion of the aperture plate to the portion of the outermost surface of the portion of the light transmissive material covering the light source die within the first cavity and to a portion of an outermost portion of the first opaque light barrier portion.

23. The method of claim 17, wherein step (d) comprises forming the second opaque barrier portion by covering a portion of the first cavity with a portion of an aperture plate.

24. The method of claim 23, wherein step (d) further comprises using an opaque epoxy to attach a portion of the aperture plate to an outermost portion of the first opaque light barrier portion.

25. The method of claim 17, further comprising:

(e) forming a third opaque light barrier portion that extends from the first opaque light barrier portion, in a direction towards the second cavity, wherein the third opaque light barrier portion is configured to reduce an amount of specular reflections that would be detected by the one or more light detecting elements of the light detector die, if a light transmissive cover plate were placed over the first and second cavities.

26. The method of claim 17, further comprising:

(e) covering at least a portion of the light source die with a lens that is off-centered relative to a center of the one or more light emitting elements of the light source die, such that the center of the lens is offset in a direction away from the first opaque light barrier portion, and such that the lens is laterally located relative to the second opaque light barrier portion.

27. A device, comprising:

a light source die including one or more light emitting elements;

a light detector die including one or more light detecting elements;

a light transmissive material covering the light source die and the light detector die;

a first opaque light barrier portion configured to block light from being transmitted directly from the light source die to the light detector die, said first opaque light barrier portion between the light source die and the light detector die; and

a second opaque light barrier portion extending over a portion of an outermost surface of the portion of the light transmissive material covering the light source die and extending from the first opaque light barrier portion, in a direction toward the light source die, a distance greater than an entire gap between the first opaque light barrier portion and at least one of the one or more light emitting elements of the light source die; and

a light transmissive cover plate placed over the light transmissive material, and thus, over the light source die and the light detector die;

wherein the second opaque light barrier portion is configured to reduce an amount of specular reflections caused by the light transmissive cover plate being over the light source die.

28. The device of claim 27, wherein a portion of the second opaque light barrier portion covers at least a portion of at least one of the one or more light emitting elements of the light source die.

29. A system, comprising:

a light source die including one or more light emitting elements;

a driver configured to drive the light source die;

a light detector die including one or more light detecting elements and configured to produce a signal indicative of an amount of detected light;

a processor and/or circuitry configured to detect a proximity of an object in dependence on the signal indicative of the amount of detected light;

a subsystem configured to be enabled or disable based on the detected proximity of an object;

a light transmissive material covering the light source die and the light detector die;

a first opaque light barrier portion configured to block light from being transmitted directly from the light source die to the light detector die, said first opaque light barrier portion between the light source die and the light detector die;

a second opaque light barrier portion extending from the first opaque light barrier portion, in a direction toward the light source die, a distance greater than an entire gap between the first opaque light barrier portion and at least one of the one or more light emitting elements of the light source die; and

a light transmissive cover placed over the light source die and the light detector die;

wherein the second opaque light barrier portion is configured to reduce an amount of specular reflections caused by the light transmissive cover being placed over the light source die;

wherein the first opaque light barrier portion separates a portion of the light transmissive material covering the light source die from a portion of the light transmissive material covering the light detector die; and

wherein the second opaque light barrier portion covers a portion of an outermost surface of the portion of the light transmissive material covering the light source die.