Optical sensor sensing illuminance and proximity

• US 10,082,576 B2
• Filed: 06/18/2014
• Issued: 09/25/2018
• Est. Priority Date: 09/27/2013
• Status: Active Grant

• Current Assignee: Magnachip Semiconductor Limited (Magnachip Semiconductor)
• Original Assignee: Magnachip Semiconductor Limited (Magnachip Semiconductor)
• Inventors: Lee, Yongsup, Lim, Daeho
• Primary Examiner(s): LEE, JOHN R
• Application Number:
  US14/308,105
• Publication Number:
  US 20150090866A1
• Time in Patent Office: 1,560 Days
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 7/4816 of receivers alone
• CPC Class Codes: H01L 27/1443 with at least one potential jump or surface barrier
• CPC Class Codes: H01L 27/14621 Colour filter arrangements
• CPC Class Codes: H01L 27/14623 Optical shielding

Abstract

An optical sensor includes photodiodes and optical filters that are arranged on the photodiodes. The photodiodes and optical filters may be spaced apart from each other. The optical filters include an infrared blocking filter and at least one visible light filter and the optical sensor measures a light quantity of a specific wavelength band in a visible light band through the photodiodes, wherein a specific visible light filter is arranged on the photodiodes. Therefore, the optical sensor has a simplified structure and may function as an ambient illuminance sensor, a proximity sensor, and a color sensor.

Claims

1. An optical sensor comprising:

a first photodiode, wherein only a visible light filter is arranged on the first photodiode;

a second photodiode, wherein only an infrared blocking filter is arranged on the second photodiode; and

a third photodiode, wherein the third photodiode has no filters arranged thereon,

wherein the optical sensor performs a first difference operation between second and third measured values measured through the second and third photodiodes, respectively, to measure a distance of an object and performs a second difference operation between a result of the first difference operation and a first measured value measured through the first photodiode to measure an illuminance of a specific wavelength.

2. The optical sensor of claim 1, wherein the photodiodes are spaced apart from each other and all of the filters are spaced apart from each other.

3. The optical sensor of claim 1, wherein the visible light filter comprises:

an infrared pass filter configured to block visible light and to pass an infrared ray; and

a color filter configured to pass the specific wavelength band from the visible light band.

4. The optical sensor of claim 3, wherein the color filter comprises red, green and blue filters configured to respectively pass monochromatic light corresponding to a red color, a green color, and a blue color, and the red, green, and blue filters are laid upon each other to form the infrared pass filter.

5. An optical sensor, comprising:

a first photodiode configured to measure a light quantity of an infrared ray, wherein only a visible light filter that is an infrared pass filter passing infrared light is arranged on the first photodiode;

a second photodiode configured to measure a dark current of the second photodiode, wherein a visible light filter that is an infrared pass filter passing infrared light and an infrared blocking filter are arranged on the second photodiode; and

a third photodiode configured to measure a light quantity for a specific wavelength of a visible light wherein only a visible light filter is arranged on the third photodiode,

wherein the optical sensor performs a difference operation between the light quantity of the infrared ray measured by the first photodiode and the dark current measured by the second photodiode to measure an adjusted distance of an object, and

the optical sensor performs a difference operation between the light quantity for the specific wavelength measured by the third photodiode and the light quantity of the infrared ray measured by the first photodiode to further measure an adjusted illuminance for a specific wavelength.

6. The optical sensor of claim 5, further comprising:

a fourth photodiode configured to measure a light quantity of a visible light and an infrared ray wherein the fourth photodiode has no filters arranged thereon.

7. The optical sensor of claim 5, wherein each infrared pass filter is formed by laying upon each other a red color, a green color, and a blue color filter.

8. The optical sensor of claim 6, wherein the optical sensor measures an ambient illuminance based on the light quantity of the infrared ray measured by the first photodiode and the light quantity of the visible light and the infrared ray measured by the fourth photodiode.

12. The sensor of claim 6, wherein the optical sensor performs a difference operation between the light quantity of the visible light and the infrared ray measured through the fourth photodiode and the light quantity of the infrared ray measured by the first photodiode to measure an adjusted ambient illuminance.

9. A method of using an optical sensor, comprising:

measuring a first quantity of light in an infrared ray received through a first photodiode where only an infrared pass filter is arranged;

measuring a second quantity of light received through a second photodiode where only an infrared blocking filter is arranged;

measuring a third quantity of light received through a third photodiode where only a color filter is arranged; and

measuring the ambient illuminance and the position of an object based on the measured first, second, and third quantities of light.

10. The method of claim 9, further comprising:

performing a color balancing using the third quantity of light.

11. The method of claim 9, further comprising:

measuring a fourth quantity of light received through a fourth photodiode on which no filters are arranged; and

correcting for a dark current using the fourth quantity of light received through the fourth photodiode.

13. An optical sensor, comprising:

a first photodiode configured to measure a first measured value comprising a light quantity of an infrared ray, wherein a first visible light filter is arranged on the first photodiode; and

a second photodiode configured to measure a second measured value consisting of a dark current of the second photodiode, wherein a second visible light filter and an infrared blocking filter are arranged on the second photodiode,

wherein the optical sensor performs a difference operation between the first measured value measured through the first photodiode and the second measured value measured through the second photodiode to further measure a distance of an object based on a result of the difference operation.