Optical proximity sensor package with molded infrared light rejection barrier and infrared pass components

• US 8,779,361 B2
• Filed: 06/30/2009
• Issued: 07/15/2014
• Est. Priority Date: 06/30/2009
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Costello, James, Saravanan, Rani, Tan, Wee Sin
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Green, Yara B
• Application Number:
  US12/495,739
• Publication Number:
  US 20100327164A1
• Time in Patent Office: 1,841 Days
• Field of Search: 250/216, 250/338.1, 250/339.06, 257/82, 257/678, 257/660, 257/99, 257/81, 257/100
• US Class Current: 250/338.1
• CPC Class Codes: G01D 5/34715 Scale reading or illumination devices
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 24/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/14 Integrated circuits
• CPC Class Codes: H01L 31/167 the light sources and the devices sensitive to radiation all being semiconductor devices characterised by potential barriers
• CPC Class Codes: H01L 31/173 formed in, or on, a common substrate
• CPC Class Codes: H01L 33/56 Materials, e.g. epoxy or silicone resin
• CPC Class Codes: H03K 17/941 using an optical detector H03K17/968 takes precedence
• CPC Class Codes: H03K 2017/9455 constructional details
• CPC Class Codes: H03K 2217/94108 making use of reflection
• CPC Class Codes: Y10T 29/4913 Assembling to base an electrical component, e.g., capacitor, etc.

Abstract

An optical proximity sensor is provided that comprises an infrared light emitter an infrared light detector, a first molded optically transmissive infrared light pass component disposed over and covering the light emitter and a second molded optically transmissive infrared light pass component disposed over and covering the light detector. Located in-between the light emitter and the first molded optically transmissive infrared light pass component, and the light detector and the second molded optically transmissive infrared light pass component is a substantially optically non-transmissive infrared light barrier component. The infrared light barrier component substantially attenuates or blocks the transmission of undesired direct, scattered or reflected light between the light emitter and the light detector, and thereby minimizes optical crosstalk and interference between the light emitter and the light detector.

Claims

1. An optical proximity sensor, comprising:

a substrate;

an infrared light emitter mounted on the substrate and operably connected to and driven by a light emitter driving circuit;

a light detector also mounted on the substrate and operably connected to and driven by a detector sensing circuit;

a first molded optically transmissive infrared light pass component disposed over and covering the light emitter;

a second molded optically transmissive infrared light pass component disposed over and covering the light detector, wherein the second component is discrete and separate from the first component; and

a molded substantially optically non-transmissive infrared light barrier component disposed between and separating the first and second optically transmissive infrared light pass components, wherein the infrared light barrier component, first component, and second component are mounted on a common surface of the substrate, wherein the infrared light barrier component is molded to the first component and the second component, and wherein the infrared light barrier component further covers the light emitter driving circuit and the detector sensing circuit;

wherein at least a first portion of light emitted by the light emitter passes through the first component, and at least a second portion of the first portion of light reflected from an object of interest in proximity to the sensor passes through the second component for detection by the light detector, and the infrared light barrier component substantially attenuates or blocks the transmission of undesired direct, scattered or reflected light between the light emitter and the light detector and thereby minimizes optical crosstalk and interference between the light emitter and the light detector.

2. The optical proximity sensor of claim 1, wherein at least one of the first and second infrared light pass components comprises an optically transmissive epoxy, polymer or plastic.

3. The optical proximity sensor of claim 1, wherein the first and second infrared light pass components and the infrared light barrier component are configured to bond to one another, and bonds formed therebetween do not delaminate under normal operating conditions.

4. The optical proximity sensor of claim 1, wherein the infrared light barrier component covers substantially all of the common surface of the substrate that is not covered by the first component and the second component and wherein the infrared light barrier component comprises a substantially optically non-transmissive moldable material, epoxy, polymer or plastic.

5. The optical proximity sensor of claim 1, wherein the infrared light barrier component further comprises an infrared cut or blocking additive.

6. The optical proximity sensor of claim 1, further comprising a substrate upon which the light emitter and the light detector are operably mounted.

7. The optical proximity sensor of claim 6, wherein the substrate is a printed circuit board (“

PCB”

).

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

9. The optical proximity sensor of claim 1, further comprising at least one integrated circuit operably connected to the light emitter and the light detector, and configured to control the operation of the light detector and the light detector, and to process output signals provided by the light detector.

10. The optical proximity sensor of claim 9, wherein the at least one integrated circuit further comprises a proximity sensor application specific integrated circuit (ASIC) and a master control unit (MCU).

11. The optical proximity sensor of claim 1, further comprising an ambient light sensor.

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

13. The optical proximity sensor of claim 11, wherein the portable electronic device is a mobile telephones a personal data assistant (PDA), a laptop computer, a notebook computer, or a computer.

14. The optical proximity sensor of claim 1, wherein the light emitter is an LED.

15. The optical proximity sensor of claim 1, wherein the light detector is a positive-intrinsic-negative (“

PIN”

) diode.

16. The optical proximity sensor of claim 1, wherein a molded optically transmissive lens is formed over the light emitter or the light detector.

17. 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, the infrared light detector being spaced apart from the infrared light emitter on the substrate;

molding or casting a first optically transmissive infrared light pass component over and covering the light emitter;

molding or casting a second optically transmissive infrared light pass component over and covering the light detector, the second optically transmissive infrared light pass component being discrete and separate from the first optically transmissive infrared light pass component;

molding or casting a substantially optically non-transmissive infrared light barrier component between the discrete first and second optically transmissive infrared light pass components thereby separating the first and second optically transmissive infrared light pass components, wherein the infrared light barrier component is molded to the first component and the second component, and wherein the infrared light barrier component extends to at least one border of the substrate; and

bonding the substantially optically non-transmissive infrared light barrier component to the first and second optically transmissive infrared light pass components.

18. The method of claim 17, wherein the first and second optically transmissive infrared light pass components are molded or casted in the same step and wherein the substantially optically non-transmissive infrared light barrier component is bonded to the first and second optically transmissive infrared light pass components during the molding or casting of the substantially optically non-transmissive infrared light barrier component.

19. The method of claim 17, wherein optically transmissive lenses are formed over the light emitter and the light detector when the first and second optically transmissive infrared light pass components are molded or casted.

20. The method of claim 17, wherein the light emitter or the light detector is die-attached to the substrate.

21. The method of claim 17, wherein the light emitter or the light detector is wire-bonded to the substrate.

22. The method of claim 17, wherein the first and second optically transmissive infrared light pass components are transfer-molded.

23. The method of claim 17, further comprising forming light guides when the first and second optically transmissive infrared light pass components are molded or casted.

24. The method of claim 17, further comprising attaching a light emitter driver integrated circuit comprising an ambient light sensor to the substrate.

25. The method of claim 17, wherein molding or casting the substantially optically non-transmissive infrared light barrier component further comprises sheet casting the light barrier component.

26. The method of claim 17, wherein the resulting molded optical proximity sensor is singulated by sawing.

27. The method of claim 17, wherein a plurality of proximity sensors are formed on a panel simultaneously.