# US 8,786,199 B2 · Method for compensating and checking light amount of light-emitting device

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- Number: US 8,786,199 B2
- Document ID: US8786199B2
- Status: Granted
- Kind: B2
- Application number: 13/572,032
- Filed: 2012-08-10
- Published: 2013-12-12
- Granted: 2014-07-22
- Earliest claimed: 2012-06-08
- Assignees: Nisho Image Tech Inc.
- Applicants: Harunobu Yoshida; Tz-Liang Chang; Po-Hsiung Peng
- Inventors: Harunobu Yoshida; Tz-Liang Chang; Po-Hsiung Peng
- Web page: https://patentgrep.com/patent/US8786199B2

## CPC

- G03G 15/043: with means for controlling illumination or exposure (G03G15/041 takes precedence)
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A method for compensating and checking a light amount is applicable to a light-emitting device including a plurality of light-emitting elements, and the following steps are successively executed on the light-emitting elements: measuring an original light amount output by a light-emitting element within a reference time interval; generating a calibration value corresponding to the light-emitting element according to the measured original light amount and a reference light amount; and adjusting light output of the light-emitting element according to the calibration value, so that the original light amount reaches a target light amount.

## Claims

### Claim 1

A method for compensating and checking a light amount of a light-emitting device, wherein the light-emitting device comprises a plurality of light-emitting elements, and the method for compensating and checking a light amount comprises:
successively testing each of the light-emitting elements by performing the following steps thereon:
measuring an original light amount output by the light-emitting element within a reference time interval;
generating a calibration value corresponding to the light-emitting element according to the measured original light amount and a reference light amount, wherein the calibration value is a lighted duration of the light-emitting element; and
adjusting a light output of the light-emitting element according to the calibration value, so that the original light amount reaches a target light amount.

### Claim 2 (depends on 1)

The method for compensating and checking a light amount according to claim 1, wherein after the adjusting the original light amount to a target light amount according to the calibration value, the method comprises:
detecting whether the target light amount is substantially the same as the reference light amount, and outputting an output signal, wherein the output signal indicates that the light-emitting device is normal or abnormal.

### Claim 3 (depends on 1)

The method for compensating and checking a light amount according to claim 1, wherein before the adjusting a light output of the light-emitting element according to the calibration value, so that the original light amount reaches a target light amount, the method comprises:
determining whether the calibration value exceeds a proper range, and outputting an output signal, wherein the output signal indicates that the light-emitting device is normal or abnormal; and
terminating the testing of the light-emitting elements when the output signal indicates that the light-emitting device is abnormal.

### Claim 4 (depends on 1)

The method for compensating and checking a light amount according to claim 1, wherein a ratio of the reference light amount to the original light amount is substantially equivalent to a ratio of the lighted duration to the reference time interval.

### Claim 5 (depends on 1)

The method for compensating and checking a light amount according to claim 1, wherein the light-emitting device further comprises a control unit and a storage unit, and before the generating a calibration value corresponding to the light-emitting element according to comparison between a reference light amount and the measured original light amount, the method for compensating and checking a light amount comprises:
storing a comparison table of the reference light amount, the original light amount and the calibration value in the storage unit; and
reading the comparison table in the storage unit by the control unit.

### Claim 6 (depends on 1)

The method for compensating and checking a light amount according to claim 1, wherein the measuring an original light amount output by the light-emitting element within a reference time interval comprises:
turning on the light-emitting element, and turning off other light-emitting elements.

### Claim 7 (depends on 1)

The method for compensating and checking a light amount according to claim 1, further comprising:
providing a photoelectric conversion unit; and
successively moving the photoelectric conversion unit to a front of the light-emitting element being tested before the step of measuring the original light amount thereof.