Patent EP0197719A2 successfully refreshed from Google Patents.
EP0197719A2
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EP
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Light-emitting diode
Assignee: Xerox Corp
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Filing: 1986-03-27
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Granted: —
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Expires: 2006-03-27
Abstract
Abstract An electro-optic line printer comprises a record medium (13), a multigate line modulator (12) for printing picture elements or pixels in spatially-predetermined positions along a printing axis, an LED side-facet source (15) having high output intensity and a uniform far field emission, and optical means to collimate the far field emission in the tangential direction and focus the near field in the sagittal direction onto the modulator. The optical means comprises a first lens system to collect the light emitted from the LED source in both the tangential and sagittal directions, and a toric second lens to collimate the light into a sheet like beam in the tangential direction and to focus the light in the sagittal direction to a line image at the modulator. Imaging means is optically aligned between the modulator and the recording medium for imaging the modulator into the record medium. The solid-state LED side-facet emitter source, with broad uniform far field emission and high intensity eliminates the necessity for an array of individually-addressable LEDs. Deposited on one facet of the LED source is an anti-reflection (AR) coating (single or multilayer) with an index of refraction chosen to be approximately midway between the effective modal refractive index of the source and the refractive index of air.
Inventors
- 👤 Robert D. Burnham
- 👤 Thomas L. Paoli
- 👤 Robert L. Thornton
- 👤 Robert A. Sprague
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 02:01
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/84; B; B41; B41J; B41J2/00; B41J2/435; B41J2/44; B82; B82Y; B82Y20/00; G; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1238; G06K15/1242; G06K15/1252; H10H20/81; H10H20/811; H10H20/812
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
51 words
A light source including an electro-optic line modulator (12), an LED side-facet source (15) having high power density and a uniform far field emission, means (46) to collimate the far field emission in the tangential direction and means (40) to focus the near field in the sagittal direction onto the modulator.
Claim 2
Dependent Claim
51 words
A light source including an electro-optic line modulator (12), an LED side-facet source (15) having high power density and a uniform far field emission, means (46) to collimate the far field emission in the tangential direction and means (40) to focus the near field in the sagittal direction onto the modulator.
Claim 3
Dependent Claim
28 words
A source as claimed in claim 1, wherein the LED side-facet source comprises a plurality of emitters (76), and has an anti-reflection coating (90) on its emission facet.
Claim 4
Dependent Claim
116 words
An LED side-facet source having uniform far field emission and high power density for electro-optic line TIR modulators and line printers, comprising a plurality of epitaxially- deposited semiconductor layers (74-80), an active region comprising at least one of the deposited layers, a p-n junction in proximity to the active region, the layers immediately adjacent to the active region providing confinement for light generated in at least one optical cavity established in said active region and propagating between end facets of said source, an anti-reflection coating (90) deposited on one of said facets, the refractive index of the coating being approximately midway between the effective modal refractive index of the source and the refractive index of air.
Claim 5
Dependent Claim
116 words
An LED side-facet source having uniform far field emission and high power density for electro-optic line TIR modulators and line printers, comprising a plurality of epitaxially- deposited semiconductor layers (74-80), an active region comprising at least one of the deposited layers, a p-n junction in proximity to the active region, the layers immediately adjacent to the active region providing confinement for light generated in at least one optical cavity established in said active region and propagating between end facets of said source, an anti-reflection coating (90) deposited on one of said facets, the refractive index of the coating being approximately midway between the effective modal refractive index of the source and the refractive index of air.
Claim 6
Dependent Claim
15 words
The LED side-facet source of claim 3, having a plurality of spatially-disposed optical cavities (76).
Claim 7
Dependent Claim
49 words
5 . The LED side-facet source of claim 3 or 4, wherein the refractive index of the AR coating is approximated according to: wherein n air is the refractive index of air, and n active is the effective refractive index of the optical mode propogating in the active region.
Claim 8
Dependent Claim
36 words
6 . The LED side-facet source of any of claims 3 to 5, wherein the AR coating is a single coating of SiO . , Si 3 N 4 , Zr0 2 or TiO 2 .
Claim 9
Dependent Claim
19 words
The LED side-facet source of any of claims 3 to 5, wherein the AR coating is a muyltilayer coating.
Claim 10
Dependent Claim
20 words
The LED side-facet source of any of claims 3 to 7, wherein the active region is a single quantum well.
Claim 11
Dependent Claim
20 words
The LED side-facet source of any of claims 3 to 7, wherein the active region is a multiple quantum well.
Claim 12
Dependent Claim
25 words
1 0. The LED side-facet source of claim 9, wherein the wells of the multiple quantum well independently vary in thickness across the active region.
Claim 13
Dependent Claim
25 words
The LED side-facet source of claim 9 or 10, wherein the wells of the multiple quantum well independently vary in bandgap across the active region.
Claim 14
Dependent Claim
17 words
The LED side-facet source of any preceding claim, wherein the source admits radiation in the visible spectrum.
Claim 15
Dependent Claim
20 words
The LED side-facet source of any one of claims 3 to 12, wherein the source admits radiation in the infrared.
Claim 16
Dependent Claim
20 words
The LED side-facet source of any preceding claim, wherein a reflective coating is deposited on the other of said facets.
Claim 17
Dependent Claim
21 words
The LED side-facet source of claim 14, wherein the reflective coating comprises alternating layers of Al 2 O 3 and silicon.
Claim 18
Dependent Claim
22 words
The LED side-facet source of any preceding claim, wherein there is a passivation layer between the respective facet and the AR coating.
Claim 19
Dependent Claim
19 words
1 7. The LED side-facet source of claim 16, wherein the passivation layer comprises A1 2 0 3 .
Claim 20
Dependent Claim
69 words
An electro-optic line printer comprising a light-sensitive record medium (13); a light source (15) as claimed in any preceding claim arranged to direct a beam of modulated light at the medium, means (31) optically aligned between the modulator (12) and the record medium for causing the beam to fall on the record medium, and means for advancing the record medium in a cross-line direction relative to the incident beam.
References Cited (Backward Citations)
No citation records indexed.
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