Infrared proximity sensor package with improved crosstalk isolation

Patent metadata

Field	Value
Publication number	US-9733357-B2
Application number	US-62376709-A
Country	US
Kind code	B2
Filing date	Nov 23, 2009
Priority date	Nov 23, 2009
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

Disclosed are various embodiments of an infrared proximity sensor package comprising an infrared transmitter die, an infrared receiver die, a housing comprising sidewalls, a first recess, a second recess, a partitioning divider disposed between the first and second recesses, and an overlying shield comprising an infrared-absorbing material. The transmitter die is positioned in the first recess, and the receiver die is positioned within the second recess. The partitioning divider comprises liquid crystal polymer (LCP) such that the partitioning divider and the infrared-absorbing material of the shield cooperate together to substantially attenuate and absorb undesired infrared light that might otherwise become internally-reflected within the housing or incident upon the receiver as a false proximity or object detection signal.

First claim

We claim:

1. An infrared proximity sensor package, comprising:
an infrared transmitter;
an infrared receiver;
a shield disposed atop the package and having first and second apertures disposed therethrough and positioned over the infrared transmitter and the infrared receiver, respectively, such that infrared light emitted by the transmitter passes through the first aperture and infrared light reflected from an object to be detected passes through the second aperture for detection by the receiver, the shield comprising an infrared-absorbing material disposed on at least a top surface thereof;
a housing comprising sidewalls, a first recess at least partially aligned with the first aperture of the shield, a second recess at least partially aligned with the second aperture, and a partitioning divider disposed between the first and second recesses, the partitioning divider comprising a first portion and second portion, the first portion being of a first thickness and the second portion being of a second thickness different from the first thickness, the first portion substantially separating the transmitter and receiver;
wherein the transmitter is disposed in the first recess, the receiver is disposed in the second recess, and the partitioning divider comprises liquid crystal polymer (LCP) such that the partitioning divider and the infrared-absorbing material of the shield cooperate together to substantially attenuate and absorb undesired infrared light that may otherwise become internally-reflected within the housing or incident upon the receiver as a false signal.

2. The infrared proximity sensor package of claim 1 , wherein the thickness T of the partitioning divider exceeds about 0.4 mm such that at least about 90% of the infrared light internally-reflected within the housing is not detected by the receiver and is attenuated or absorbed by the shield and the LCP.

3. The infrared proximity sensor package of claim 1 , wherein the thickness T of the partitioning divider exceeds about 0.5 mm such that at least about 95% of the infrared light internally-reflected within the housing is not detected by the receiver and is attenuated or absorbed by the shield and the LCP.

4. The infrared proximity sensor package of claim 1 , wherein the thickness T of the partitioning divider exceeds about 0.6 mm such that at least about 97% of the infrared light internally-reflected within the housing is not detected by the receiver and is attenuated or absorbed by the shield and the LCP.

5. The infrared proximity sensor package of claim 1 , wherein top and side surfaces of the shield are black.

6. The infrared proximity sensor package of claim 1 , wherein the shield comprises an infrared-absorbing polymer.

7. The infrared proximity sensor package of claim 6 , wherein the infrared-absorbing polymer comprises LCP.

8. The infrared proximity sensor package of claim 1 , wherein the shield is a black coating.

9. The infrared proximity sensor package of claim 1 , further comprising a lead frame configured to fit beneath the housing, the transmitter being disposed on a first frame portion thereof, the receiver being disposed on a second frame portion thereof such that the transmitter is positioned within the first recess and the receiver is positioned within the second recess, wherein at least a portion of the lead frame is moldably integrated into the housing such at the at least a portion of the leadframe is exposed in at least one of the first and second recess of the housing.

10. The infrared proximity sensor package of claim 1 , wherein the sidewalls of the housing comprise LCP such that infrared light internally-reflected within the housing in the direction of the sidewalls is substantially attenuated or absorbed by the LCP contained therein.

11. The infrared proximity sensor package of claim 1 , wherein the sidewalls and partitioning divider of the housing are molded from LCP to form the housing as a single unitary piece of LCP.

12. The infrared proximity sensor package of claim 1 , further comprising a processor operably coupled to the transmitter and the receiver, the processor comprising transmitter driving circuitry, receiver detection circuitry and signal conditioning circuitry.

13. The infrared proximity sensor package of claim 1 , wherein the transmitter comprises an infrared LED transmitter.

14. The infrared proximity sensor package of claim 1 , wherein the receiver comprises at least one of a PIN diode, a photo-diode and a phototransistor.

15. The infrared proximity sensor package of claim 1 , wherein at least one of the transmitter and the receiver is configured for operation within a bandwidth ranging between about 800 nm and about 1100 nm.

16. The infrared proximity sensor package of claim 1 , wherein the sensor package is incorporated into an electronic device selected from the group consisting of a portable electronic device, a hand-held portable electronic device, a stationary electronic device, a washing machine, a dryer, an exercise machine, an industrial control or switching device, a camera, a toy, a mobile telephone, a cellular telephone, a portable music player, a remote control, a television, an air conditioning unit, a heating unit, an audio playback device, an audio recording device, an MP3 player, a laptop computer, a personal data assistant (PDA), a radio, and a transceiver.

17. The infrared proximity sensor package of claim 1 , wherein the sensor package is incorporated into a telephone and operably connected to at least one of an auto-volume adjustment circuit and an open-phone detection circuit.

18. The infrared proximity sensor package of claim 1 , further comprising a lens disposed over at least one of the transmitter and the receiver and within at least one of the first aperture and second aperture.

19. The infrared proximity sensor package of claim 18 , wherein the lens is configured to act as a low-cut filter that at least partially rejects wavelengths of light less than about 700 nm.

20. The infrared proximity sensor package of claim 18 , wherein the lens is formed from a thermoset epoxy or a polymer.

21. The infrared proximity sensor package of claim 1 , wherein at least one of a length and a width of the package is less than about 5 mm.

22. The infrared proximity sensor package of claim 1 , wherein a height of the package is less than about 3 mm.

23. A method of making an infrared proximity sensor package, comprising:
providing an infrared transmitter;
providing an infrared receiver;
providing a shield disposed atop the package and having first and second apertures disposed therethrough and positioned over the infrared transmitter and the infrared receiver, respectively, such that infrared light emitted by the transmitter passes through the first aperture and infrared light reflected from an object to be detected passes through the second aperture for detection by the receiver, the shield comprising an infrared-absorbing material disposed on at least a top surface thereof;
providing a housing comprising sidewalls, a first recess positioned underneath the first aperture of the shield, a second recess positioned underneath the second aperture of the shield, and a partitioning divider disposed between the first and second recesses, the partitioning divider comprising a first portion and second portion, the first portion being of a first thickness and the second portion being of a second thickness different from the first thickness, the first portion substan

Assignees

• Costello James
• Tan Wee Sin
• Avago Technologies General Ip

Inventors

• Costello James
• Tan Wee Sin

Classifications

• H10W90/756

  between a chip and a stacked lead frame, conducting package substrate or heat sink · CPC title

• G01S17/04 Primary

  Systems determining the presence of a target · CPC title

• Y10T29/49002

  Electrical device making · CPC title

• G01S7/4813 Primary

  Housing arrangements · CPC title

• H03K17/945

  Proximity switches (H03K17/96 takes precedence) · CPC title