Integrated ambient light sensor and distance sensor

• US 20090027652A1
• Filed: 07/25/2008
• Published: 01/29/2009
• Est. Priority Date: 07/25/2007
• Status: Active Grant

• Current Assignee: Eminence Electronic Technology Pvt. Ltd.
• Original Assignee: Eminence Electronic Technology Pvt. Ltd.
• Inventors: Canfield, John, Chang, Tom
• Granted Patent: US 8,125,619 B2
• Time in Patent Office: Days
• US Class Current: 356/4.10
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G01S 7/4815 using multiple transmitters
• CPC Class Codes: H03K 17/943 using a plurality of optical emitters or detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/94108 making use of reflection

Abstract

An integrated proximity and light sensor includes an indicating light-emitting device (“ILD”), a projecting light-emitting device (“PLD”), and a light sensing integrated circuit (“LSIC”) configured as a single package. The LSIC controls each of the ILD and the PLD to emit light therefrom and the LSIC is configured to detect an ambient light level and also to detect a reflection of the light projected by the PLD from a surface for proximity detection.

Claims

1. An integrated proximity and light sensor, comprising:

an indicating light-emitting device (“

ILD”

), a projecting light-emitting device (“

PLD”

), and a light sensing integrated circuit (“

LSIC”

) configured as a single package,

wherein the LSIC controls each of the ILD and the PLD to emit light therefrom,

and wherein the LSIC is configured to detect an ambient light level and also to detect a reflection of the light projected by the PLD from a surface for proximity detection.

2. The integrated proximity and light sensor of claim 1 further comprising a light isolation partition that optically isolates the PLD from the LSIC.

3. The integrated proximity and light sensor of claim 2 further comprising one or more optical ports disposed above the light isolation partition, wherein light projected from the ILD and/or the PLD transmits through the one or more optical ports.

4. The integrated proximity and light sensor of claim 1, wherein the LSIC controls the PLD to emit infrared light and the ILD to emit visible light.

5. The integrated proximity and light sensor of claim 4, wherein the ILD further includes one or more light-emitting diodes and the PLD further includes an infrared light-emitting diode.

6. The integrated proximity and light sensor of claim 1, wherein the LSIC includes one or more sensors that sense visible light to detect the ambient light level and sense infrared light for proximity detection.

7. The integrated proximity and light sensor of claim 6, wherein the one or more sensors are photodiodes.

8. The integrated proximity and light sensor of claim 1, wherein the LSIC is coupled to first and second switches, and wherein the first switch controls a first current passing through the ILD and the second switch controls a second current passing through the PLD.

9. The integrated proximity and light sensor of claim 7, wherein the first switch includes a first transistor with a first gate connected to and controlled by the LSIC and the second switch includes a second transistor with a second gate connected to and controlled by the LSIC.

10. The integrated proximity and light sensor of claim 1, wherein the LSIC chip turns off the ILD to detect the ambient light level.

11. The integrated proximity and light sensor of claim 10, wherein the LSIC turns off the ILD for a time period shorter than about 30 milliseconds to detect the ambient light level.

12. The integrated proximity and light sensor of claim 1, wherein the LSIC turns off the ILD and turns on the PLD to detect the reflection of the light projected by the PLD from the surface for proximity detection.

13. The integrated proximity and light sensor of claim 11, wherein the LSIC turns off the ILD for a time period shorter than 30 millisecond and turns on the PLD for a time period shorter than 30 millisecond to detect the reflection of the light projected by the PLD from the surface for proximity detection.

15. The integrated proximity and light sensor of claim 13 further comprising an indicating light-emitting device (“

ILD”

), wherein the LSIC controls the ILD to emit visible light therefrom and controls the PLD to emit infrared light therefrom.

14. An integrated proximity and light sensor, comprising:

a projecting light-emitting device (“

PLD”

) and a light sensing integrated circuit (“

LSIC”

) configured as a single package; and

a light isolation partition that optically isolates the PLD from the LSIC,

wherein the LSIC controls the PLD to emit light therefrom,

and wherein the LSIC is configured to detect an ambient light level and also to detect a reflection of the light projected by the PLD from a surface for proximity detection.

16. A method of operating an integrated proximity and light sensor, comprising the steps of:

programming a controller to operate the integrated proximity and light sensor in at least two modes including an ambient light sensing mode and a proximity sensing mode, wherein the proximity sensing mode further includes the steps of;

turning on a projecting light-emitting device (“

PLD”

);

detecting light while the PLD is on to obtain first data;

turning off the PLD;

detecting light while the PLD is off to obtain second data; and

determining the proximity of a surface as a function of the difference between the first data and the second data.

17. The method of operating an integrated proximity and light sensor of claim 16, wherein the PLD device is turned on for a predetermined time before and after the first step of detecting, and wherein the PLD is turned off for a predetermined time before and after the second step of detecting.

18. The method of operating an integrated proximity and light sensor of claim 16 further comprising the step of turning on an indicating light-emitting device (“

ILD”

), wherein the ILD is turned off periodically when the integrated proximity and light sensor is sensing ambient light and/or proximity.

19. The method of operating an integrated proximity and light sensor of claim 18, wherein the ILD emits visible light and the PLD emits infrared light.

20. The method of operating an integrated proximity and light sensor of claim 16, wherein the ambient light sensing mode further includes sensing visible light and the proximity sensing mode further includes sensing infrared light.