Light-emitting semiconductor device pulse drive method and pulse drive circuit
First Claim
1. A pulse drive method for one or more light-emitting semiconductor devices having a plurality of light-emitting elements emitting light at different wavelengths, the light-emitting semiconductor device pulse drive method comprising:
- first lit steps in whichat least a portion of the light-emitting elements of any of the emitted wavelengths is or are made to light as a result of being driven at one or more drive settings for each emitted wavelength,at least one optical output from the lit light-emitting element or elements is detected, andat least one of the light-emitting element drive setting or settings is adjusted based on at least one of the detected light-emitting element optical output or outputs; and
unlit steps in which the light-emitting elements of all of the emitted wavelengths are unlit for prescribed unlit time, the length of which does not depend on the light-emitting element drive setting or settings;
wherein the first lit steps are carried out in repeated fashion by switching at least a portion of the driven light-emitting element or elements one after another so as to cause at least a portion of the light-emitting elements to sequentially light in pulsed fashion in the order of emitted wavelength such that the plurality of light-emitting elements having different wavelengths are allowed to light up at different timings from each other; and
at least one iteration of the unlit steps respectively intervenes between each pair of successive iterations of the first lit steps carried out in repeated fashion, such that the light-emitting elements of different wavelengths are not lit at the same time.
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Abstract
A pulse drive method for a light-emitting semiconductor devices having a plurality of light-emitting elements emitting light at different wavelengths and comprising first lit steps in which light-emitting element(s) of any of the emitted wavelengths is/are made to light as a result of being driven at drive setting(s) for each emitted wavelength, optical output(s) from the lit light-emitting element(s) is/are detected, and the light-emitting element(s) drive setting(s) is/are adjusted based on the detected light-emitting element optical output(s); and unlit steps in which the light-emitting elements of all of the emitted wavelengths are unlit for prescribed unlit time. The first lit steps are carried out in repeated fashion while the driven light-emitting element(s) is/are switched so as to cause the light-emitting element(s) to sequentially light in pulsed fashion in turn by emitted wavelength, and the unlit step respectively intervenes between each pair of successive iterations of the first lit steps.
15 Citations
21 Claims
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1. A pulse drive method for one or more light-emitting semiconductor devices having a plurality of light-emitting elements emitting light at different wavelengths, the light-emitting semiconductor device pulse drive method comprising:
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first lit steps in which at least a portion of the light-emitting elements of any of the emitted wavelengths is or are made to light as a result of being driven at one or more drive settings for each emitted wavelength, at least one optical output from the lit light-emitting element or elements is detected, and at least one of the light-emitting element drive setting or settings is adjusted based on at least one of the detected light-emitting element optical output or outputs; and unlit steps in which the light-emitting elements of all of the emitted wavelengths are unlit for prescribed unlit time, the length of which does not depend on the light-emitting element drive setting or settings; wherein the first lit steps are carried out in repeated fashion by switching at least a portion of the driven light-emitting element or elements one after another so as to cause at least a portion of the light-emitting elements to sequentially light in pulsed fashion in the order of emitted wavelength such that the plurality of light-emitting elements having different wavelengths are allowed to light up at different timings from each other; and at least one iteration of the unlit steps respectively intervenes between each pair of successive iterations of the first lit steps carried out in repeated fashion, such that the light-emitting elements of different wavelengths are not lit at the same time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A pulse drive circuit for one or more light-emitting semiconductor devices having a plurality of light-emitting elements emitting light at different wavelengths, the light-emitting semiconductor device pulse drive circuit comprising:
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one or more drive circuits sequentially driving at least a portion of the light-emitting elements in pulsed fashion in turn by emitted wavelength at one or more drive currents set for each emitted wavelength; one or more detection circuits detecting one or more optical outputs from at least a portion of the light-emitting elements; and one or more setting circuits adjusting one or more drive current settings of at least a portion of the light-emitting elements for each emitted wavelength based on the results of detection carried out by the one or more detection circuits; wherein the one or more drive circuits respectively allows the plurality of light-emitting elements having different wavelengths to light up at different timings from each other and does not allow the light-emitting elements of different wavelengths to light up at the same time by setting a prescribed unlit time, the length of which does not depend on the one or more drive current settings during which the light-emitting elements of all of the emitted wavelengths are unlit between lit times for each emitted wavelength of the at least a portion of the light-emitting elements. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification