Patent ID: 9534955
Date: 2017-01-03
CPC Classifications: G01J

Claim:
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.