Diode laser source with concurrently driven light emitting segments
First Claim
1. A multibeam optical unit comprising;
- a plurality of laser elements formed in a monolithic laser diode array, each laser element comprising a plurality of laser emitters addressable as an emitter group providing an output of plural light beams;
means for electrically addressing said laser elements independently of one another;
beam optics disposed in front of each of said laser elements, said beam optics including a lens system disposed in front of and aligned with a corresponding one of said laser emitter groups to converge the light beams emitted from the plural emitters of an emitter group into a single overlapping spot for that group to preserve their overall brightness;
said emitter groups forming with said beam optics a plurality of high intensity, single overlapped light spots, each of which comprises light beams from all of the emitters of an emitter group so that, at a focal plane of said beam optics, a plurality of spatially aligned high intensity overlap spots is formed substantially aligned in a plane of said laser elements, failure of any one or emitters in any particular emitter group will cause only a slight decrease in optical power and brightness with substantially no size change in its single overlapped light spot.
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Accused Products
Abstract
A diode laser source including a laser diode whose emitting element array or elements or subarray is divided into a plurality of concurrently driven laser segments. Beam filling and focusing optics are disposed in front of the segments so that light from the segments in each element or subarray converges to a single overlapping spot. The optics include a beam filling lens array collimating the light from the segments and either a single focusing lens or a second lens array focusing the collimated light to corresponding spots. In the case of a element laser diode array, each multi-segment element or subarray of the array is individually addressable so as to be driven independently from the other multi-elements array elements. The segmentation of laser elements improves laser life by reducing thermal gradients and isolating any local failures to a single segment, while separately focusing of the segments of each subarray to overlapping light spots increases the tolerance of the source to local failures. Two or more segments in a given element or subarray must fail before the source is considered to fail.
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Citations
35 Claims
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1. A multibeam optical unit comprising;
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a plurality of laser elements formed in a monolithic laser diode array, each laser element comprising a plurality of laser emitters addressable as an emitter group providing an output of plural light beams; means for electrically addressing said laser elements independently of one another; beam optics disposed in front of each of said laser elements, said beam optics including a lens system disposed in front of and aligned with a corresponding one of said laser emitter groups to converge the light beams emitted from the plural emitters of an emitter group into a single overlapping spot for that group to preserve their overall brightness; said emitter groups forming with said beam optics a plurality of high intensity, single overlapped light spots, each of which comprises light beams from all of the emitters of an emitter group so that, at a focal plane of said beam optics, a plurality of spatially aligned high intensity overlap spots is formed substantially aligned in a plane of said laser elements, failure of any one or emitters in any particular emitter group will cause only a slight decrease in optical power and brightness with substantially no size change in its single overlapped light spot. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14)
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11. A multibeam optical unit comprising:
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a laser diode array comprising a plurality of laser diode emitters each emitting a separate diverging light beam from its respective emitter, said emitters being sufficiently separated from one another to permit separate operation among the emitters; said laser diode array divided into a plurality of subarrays of diode lasers, said diode laser emitters of each subarray being driven as a group from a single current source so that said subarrays in said laser diode array are independently addressable; optical means in alignment to receive the light beams from said array for reducing their divergence in at least one orthogonal direction; and a plurality of lenslet arrays, one of said lenslet arrays for each of said subarrays and comprising a plurality of separate lenslets, one for each of the light beams of the subarray, for focusing each of the light beams in orthogonal beam directions in overlapped relation to form a single light spot for delivery to a beam application. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A multibeam optical unit comprising:
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a laser source comprising a plurality of subarrays with each subarray having a plurality of emitters spaced a predetermined distance from one another; means for independently electrically addressing the emitters of each of said laser subarrays as a single group; an optical lens unit for each of said laser subarrays comprising a first lens unit having a plurality of lenslets, one for each emitter of said laser subarrays to provide beam filling of said light beams within each of the respective lenslets so that the spacing between adjacent emitters at the source of each of said laser subarrays is reduced or substantially eliminated at said first lens unit. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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34. In a laser printing system, a multibeam optical unit comprising:
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a laser source comprising a plurality of subarrays with each subarray having a plurality of emitters spaced a predetermined distance from one another and producing diverging light beams with intervening dead spacing; means for independently electrically addressing the emitters of each of said laser subarrays as a single group; an optical lens unit for each of said laser subarrays comprising a first lens unit having a plurality of lenslets, one for each emitter of said lager subarrays to provide beam filling of said light beams within each of the respective lenslets so that the intervening dead spacing between adjacent light beams at the source of each of said laser subarrays is reduced or substantially eliminated; said optical lens unit further focusing the respective light beams of each said laser subarrays in overlapped relation to form a plurality of spatially separate light spots for delivery to the laser printing system. - View Dependent Claims (35)
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Specification