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REDUCTION OF DARK COUNT RATES AND IMPROVEMENT OF THE FILL FACTOR IN SOLID STATE PHOTOMULTIPLIERS AND AVALANCHE PHOTODIODE ARRAYS

IP.com Disclosure Number: IPCOM000199110D
Publication Date: 2010-Aug-26
Document File: 3 page(s) / 21K

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention discloses an array of micro lenses having a pitch size same as a pitch size of a Solid State Photomultiplier (SSPM) or an Avalanche Photodiode Array (APD Array). The array of micro lenses is placed and aligned in front of a sensitive area of the SSPM or the APD array. Further, an incident light ray is focused by each element of the micro lens array on individual pixels of the SSPM and the APD array. The usage of micro lens array improves fill factor in the SSPM and the APD array. Further, a pixel size of the SSPM can be made smaller while effective sensitive area of the array of the SSPM can be kept as large as the physical SSPM size.

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RP13493

REDUCTION OF DARK COUNT RATES AND IMPROVEMENT OF THE FILL FACTOR IN SOLID STATE PHOTOMULTIPLIERS AND AVALANCHE

PHOTODIODE ARRAYS

BRIEF ABSTRACT

    The present invention discloses an array of micro lenses having a pitch size same as a pitch size of a Solid State Photomultiplier (SSPM) or an Avalanche Photodiode Array (APD Array). The array of micro lenses is placed and aligned in front of a sensitive area of the SSPM or the APD array. Further, an incident light ray is focused by each element of the micro lens array on individual pixels of the SSPM and the APD array. The usage of micro lens array improves fill factor in the SSPM and the APD array. Further, a pixel size of the SSPM can be made smaller while effective sensitive area of the array of the SSPM can be kept as large as the physical SSPM size.

KEYWORDS

    Dark Count Rates, fill factor, SSPM, APD Array, sensitive area, micro lens array, pixel size, high dark count rates.

DETAILED DESCRIPTION

    In a typical multimode Focal Plane Array (FPA), all of the FPA's conducting layers including all of the absorbing layers are patterned to form electrically isolated commons for all photo detector sub-arrays to support independent mode biasing of the photo detectors. The commons are configured

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RP13493

to accommodate large bias amplitude differences and different temporal bias profiles to address a wide range of multimode sensing applications. Further, a typical InGaAs photo detector is provided with an avalanche photodiode (APD), a p-intrinsic-n (PIN) photodiode, and a micro lens structure that provides high optical fill factors for both the APD and PIN photodiodes. However, a disadvantage is that both the FPA and APD have higher dark count rates.

    Another conventional method that attempts a reduction in dark count rates is concentrating light with lenses and other large-scale optical elements. However, the conventional method could not reduce the dark count rates signif...