Method for automated testing of the modulation transfer function in image sensors
First Claim
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1. A method of testing a modulation transfer function (MTF) of an imager comprising photosensitive cells, the method comprising:
- exposing the imager to a photon source;
measuring an output of first and second photosensitive cells, wherein the first cell is blocked from the photon source by a layer of opaque material formed within the imager; and
calculating the MTF using the measured outputs.
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Abstract
A method for automatically measuring the modulation transfer function of an imager is disclosed. A opaque mask is placed over selected columns and rows of the imager during fabrication. In the course of an automated process, photons are uniformly shone over the image sensor. The amount of the input signal that flows from the unmasked pixel cells to the masked pixel cells can then be measured and the modulation transfer function can be determined.
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Citations
60 Claims
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1. A method of testing a modulation transfer function (MTF) of an imager comprising photosensitive cells, the method comprising:
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exposing the imager to a photon source; measuring an output of first and second photosensitive cells, wherein the first cell is blocked from the photon source by a layer of opaque material formed within the imager; and calculating the MTF using the measured outputs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of testing a modulation transfer function (MTF) of an imager comprising photosensitive cells, the method comprising:
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exposing a first imager to a collimated photon source; measuring an output of first and second adjacent photosensitive cells, wherein the first cell is blocked from the photon source by a layer of opaque material; calculating the MTF using the measured output to form a test standard; exposing the first imager to a non-collimated photon source; measuring an output of first and second adjacent photosensitive cells, wherein the first cell is blocked from the photon source by a layer of opaque material; calculating the MTF using the measured output for the test using the non-collimated photon source; comparing results of said first standardizing test with results of said second test using a non-collimated photon source; and determining whether said results attained with said second test using the non-collimated photon source are within an acceptable error margin as compared with the result attained with said first standardizing test. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of testing a modulation transfer function (MTF) of an imager comprising photosensitive cells, the method comprising:
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exposing a first and second predetermined number of photosensitive cells in at least one of a row and column of adjacent photosensitive cells of the imager to a photon source, wherein the first predetermined number of photosensitive cells are blocked from the photon source by a layer of opaque material formed within the imager; measuring an output of the first and second predetermined number of photosensitive cells; and calculating the MTF using the measured outputs. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A method of testing a modulation transfer function (MTF) of an imager comprising photosensitive cells, the method comprising:
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exposing a first imager to a collimated photon source; measuring an output of a first row or column and a second row or column of adjacent photosensitive cells, wherein the first row or column of cells are blocked from the photon source by a layer of opaque material; calculating the MTF using the measured outputs to form a test standard; exposing the first imager to a non-collimated photon source; measuring an output of said first row or column and said second row or column of adjacent photosensitive cells; calculating the MTF using the measured outputs for the test using the non-collimated photon source; comparing results of said first standardizing test with results of said second test using a non-collimated photon source; and determining whether said results attained with said second test using the non-collimated photon source are within an acceptable error margin as compared with the result attained with said first standardizing test. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45)
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46. A computer program stored on a computer readable storage medium for operating a computer to perform a method of testing an imager array, the method comprising:
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exposing the imager to a photon source; measuring an output of first and second photosensitive cells, wherein the first cell is blocked from the photon source by a layer of opaque material formed within the imager; and calculating the MTF using the measured outputs. - View Dependent Claims (47, 48, 49)
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50. A computer program stored on a computer readable storage medium for operating a computer to perform a method of testing an imager array, the method comprising:
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exposing a first and second predetermined number of photosensitive cells in at least one of a row and column of adjacent photosensitive cells of the imager to a photon source, wherein the first predetermined number of photosensitive cells are blocked from the photon source by a layer of opaque material formed within the imager; measuring an output of the first and second predetermined number of photosensitive cells; and calculating the MTF using the measured outputs. - View Dependent Claims (51)
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52. A test system for an imager array containing photosensitive cells, the test system comprising:
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a light source for exposing at least a portion of the imager array to photons; a processor coupled to an output of first and second adjacent photosensitive cells of said array, wherein the first cell is blocked from the photon source by a layer of opaque material formed within the imager, said processor determining a modulation transfer function of said imager array from the output signal of said blocked and unblocked photosensitive cells. - View Dependent Claims (53, 54, 55, 56)
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57. A test system for an imager array containing photosensitive cells, the test system comprising:
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a light source for exposing at least a portion of the imager array to photons; a processor coupled to an output of a first and second predetermined number of photosensitive cells in at least one of a row and column of adjacent photosensitive cells of said array, wherein the first predetermined number of photosensitive cells are blocked from the light source by a layer of opaque material formed within the imager, said processor determining a modulation transfer function of said imager array from the output signal of said blocked and unblocked photosensitive cells. - View Dependent Claims (58, 59, 60)
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Specification