Multi-channel UV detection for improved solar spectrum and UV index estimation

Patent metadata

Field	Value
Publication number	US-9534955-B2
Application number	US-201514671063-A
Country	US
Kind code	B2
Filing date	Mar 27, 2015
Priority date	Nov 6, 2014
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

The present disclosure describes an ultraviolet (UV) sensor configured to detect a target UV spectrum (e.g., UVB spectrum). The UV sensor includes a first photodiode with a first UV spectral response and a second photodiode with a second UV spectral response. A filter layer having a graded spectral response is formed over the second photodiode, and the second UV spectral response is affected by a controlled parameter (e.g., thickness) of the filter layer. The UV sensor further includes a subtraction circuit coupled with the first photodiode and the second photodiode. The subtraction circuit is configured to provide a differential response based on a difference between the first UV spectral response and the second UV spectral response. The controlled parameter of the filter layer can be selected such that the differential response provides a detected spectral response of the target spectrum.

First claim

What is claimed is:

1. A multi-channel ultraviolet (UV) sensor, comprising:
a first photodiode with a first UV spectral response;
a second photodiode with a second UV spectral response;
a filter layer having a graded spectral response, the filter layer being formed over the second photodiode, wherein the second UV spectral response is affected by a controlled parameter of the filter layer;
a first subtraction circuit coupled with the first photodiode and the second photodiode, the first subtraction circuit being configured to provide a first differential response based on a difference between the first UV spectral response and the second UV spectral response;
a third photodiode with a third UV spectral response;
a metal layer formed over the third photodiode for leakage current cancellation; and
a second subtraction circuit coupled with the first photodiode and the third photodiode, the second subtraction circuit being configured to provide a second differential response based on a difference between the first UV spectral response and the third UV spectral response.

2. The multi-channel UV sensor of claim 1 , wherein the first differential response is associated with a target spectrum, and the controlled parameter is selected to achieve the target spectrum.

3. The multi-channel UV sensor of claim 1 , further comprising a UVA filter formed over the first and second photodiodes.

4. The multi-channel UV sensor of claim 1 , wherein the filter layer comprises a layer with spectrally graded material absorption.

5. The multi-channel UV sensor of claim 4 , wherein the filter layer comprises a passivation layer.

6. A multi-channel ultraviolet (UV) sensor, comprising:
a first photodiode with a first UV spectral response;
a second photodiode with a second UV spectral response;
a filter layer having a graded spectral response, the filter layer being formed over the second photodiode, wherein the second UV spectral response is affected by a controlled parameter of the filter layer;
a first subtraction circuit coupled with the first photodiode and the second photodiode, the first subtraction circuit being configured to provide a first differential response based on a difference between the first UV spectral response and the second UV spectral response;
a third photodiode with a third UV spectral response;
a fourth photodiode with a fourth UV spectral response;
a metal layer formed over the fourth photodiode for leakage current cancellation; and
a second subtraction circuit coupled with the third photodiode and the fourth photodiode, the second subtraction circuit being configured to provide a second differential response based on a difference between the third UV spectral response and the fourth UV spectral response.

7. The multi-channel UV sensor of claim 6 , wherein the first differential response is associated with a first target spectrum, and the controlled parameter is selected to achieve the target spectrum.

8. The multi-channel UV sensor of claim 6 , further comprising:
a UVB filter formed over the first and second photodiodes; and
a UVA filter formed over the third and fourth photodiodes.

9. The multi-channel UV sensor of claim 6 , wherein the filter layer comprises a layer with spectrally graded material absorption.

10. The multi-channel UV sensor of claim 9 , wherein the second UV spectral response is affected by a thickness of the layer.

11. The multi-channel UV sensor of claim 9 , wherein the filter layer comprises a passivation layer.

Assignees

• Maxim Integrated Products

Inventors

• Edwards Christopher F
• Allen Dan G
• Pei Cheng-Wei
• Mcguire Timothy K
• Jones Joy T
• Kerness Nicole D

Classifications

• G01J3/36

  Investigating two or more bands of a spectrum by separate detectors · CPC title

• G01J1/429

  applied to measurement of ultraviolet light (using counting tubes G01T) · CPC title

• G01J3/2803 Primary

  using photoelectric array detector · CPC title

• G01J2001/4266

  for measuring solar light · CPC title

• G01J2003/2806

  Array and filter array · CPC title