Patent US4024431A successfully refreshed from Google Patents.
Patent US5793062A successfully refreshed from Google Patents.
US5793062A
Expired / Lapsed
US
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Transparent substrate light emitting diodes with directed light output
Assignee: Lumileds LLC
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Filing: 1997-10-24
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Granted: 1998-08-11
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Expires: 2017-10-24
Abstract
Abstract Methods for the fabrication of TS LED chips with improved light extraction and optics, particularly increased top surface emission, and the TS LEDs so fabricated are described. Non-absorbing DBRs within the chip permit the fabrication of the LEDs. The transparent DBRs redirect light away from absorbing regions such as contacts within the chip, increasing the light extraction efficiency of the LED. The non-absorbing DBRs can also redirect light toward the top surface of the chip, improving the amount of top surface emission and the on-axis intensity of the packaged LED. These benefits are accomplished with optically non-absorbing layers, maintaining the advantages of a TS LED, which advantages include ˜6 light escape cones, and improved multiple pass light extraction.
Inventors
- 👤 Fred A. Kish, Jr.
- 👤 Stephen A. Stockman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:30
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/814; H10H20/819; H10H20/82; H10P; H10P95/00; H10P95/50; H10W; H10W72/00; H10W72/851; H10W72/874; H10W72/884; H10W90/00; H10W90/701; H10W90/751; H10W90/756
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
225 words
A light emitting diode that does not emit coherent radiation, comprising: an active region for generating light; a substrate transparent to the light generated by the active region, the substrate underlying the active region and having a top and bottom surface and a plurality of exposed side surfaces, light generated by the active region being capable of leaving the light emitting diode through the exposed side surfaces of the substrate; a window layer transparent to the light generated by the active region, overlying the active region, the window layer having at least one top exposed surface through which light generated by the active region can pass; a first contact and a second contact for applying a voltage across the active region, at least the first and second contacts absorbing light generated by the active region; at least a first distributed Bragg reflector, substantially transparent to the light generated by the active region, the distributed Bragg reflector reflecting light striking the distributed Bragg reflector within a predefined range of angles of incidence and transmitting light generated by the active region with minimal absorption when the light strikes the distributed Bragg reflector outside the predefined range of angles of incidence, the distributed Bragg reflector redirecting light generated by the active region away from absorbing regions of the light emitting diode and towards at least one exposed surface.
Claim 2
Dependent Claim
225 words
A light emitting diode that does not emit coherent radiation, comprising: an active region for generating light; a substrate transparent to the light generated by the active region, the substrate underlying the active region and having a top and bottom surface and a plurality of exposed side surfaces, light generated by the active region being capable of leaving the light emitting diode through the exposed side surfaces of the substrate; a window layer transparent to the light generated by the active region, overlying the active region, the window layer having at least one top exposed surface through which light generated by the active region can pass; a first contact and a second contact for applying a voltage across the active region, at least the first and second contacts absorbing light generated by the active region; at least a first distributed Bragg reflector, substantially transparent to the light generated by the active region, the distributed Bragg reflector reflecting light striking the distributed Bragg reflector within a predefined range of angles of incidence and transmitting light generated by the active region with minimal absorption when the light strikes the distributed Bragg reflector outside the predefined range of angles of incidence, the distributed Bragg reflector redirecting light generated by the active region away from absorbing regions of the light emitting diode and towards at least one exposed surface.
Claim 3
Dependent Claim
49 words
The light emitting diode of claim 1 wherein the distributed Bragg reflector reflects light emitted by the active region in at least a first of two directions, the two directions being away from light absorbing areas of the light emitting diode and towards at least a first preferential direction.
Claim 4
Dependent Claim
41 words
The device of claim 2 wherein the active region comprises In(AlGa)P, the substrate comprises GaP, and the distributed Bragg reflector comprises a multi-layer stack of any combination of In X Al Y Ga Z P(0≦X,Y,Z≦1) and Al X' Ga 1-x As(0≦X'≦1).
Claim 5
Dependent Claim
32 words
The light emitting diode of claim 2 wherein the transparent substrate is patterned with a plurality of trenches and the Bragg reflector and the active region are grown on the patterned substrate.
Claim 6
Dependent Claim
17 words
The light emitting diode of claim 4 wherein the trenches have sidewalls angled 45° from the vertical.
Claim 7
Dependent Claim
43 words
The light emitting diode of claim 2 wherein the distributed Bragg reflector is placed between the active region and a portion of the substrate, the portion of the substrate including the surfaces of the substrate closest to and furthest from the active region.
Claim 8
Dependent Claim
49 words
The light emitting diode of claim 6 wherein a second distributed Bragg reflector is placed between the active region and at least a portion of the transparent window, the portion of the transparent window including the surfaces of the transparent window closest to and furthest from the active region.
Claim 9
Dependent Claim
24 words
The light emitting diode of claim 1 wherein the substrate is wafer bonded to a combination of the distributed Bragg reflector and active region.
Claim 10
Dependent Claim
49 words
The light emitting diode of claim 8 wherein the distributed Bragg reflector reflects light emitted by the active region in at least a first of two directions, the two directions being away from light absorbing areas of the light emitting diode and towards at least a first preferential direction.
Claim 11
Dependent Claim
24 words
The light emitting diode of claim 9 wherein scattering centers are incorporated into the wafer bond between the substrate and the active region/reflector combination.
Claim 12
Dependent Claim
24 words
The light emitting diode of claim 1 wherein a combination of the substrate and distributed Bragg reflector is wafer bonded to the active region.
Claim 13
Dependent Claim
49 words
The light emitting diode of claim 11 wherein the distributed Bragg reflector reflects light emitted by the active region in at least a first of two directions, the two directions being away from light absorbing areas of the light emitting diode and towards at least a first preferential direction.
Claim 14
Dependent Claim
24 words
The light emitting diode of claim 12 wherein scattering centers are incorporated into the wafer bond between the substrate/reflector combination and the active region.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-10 | 2002-02-09 | 2002-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-10 | 2006-02-09 | 2006-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-10 | 2010-02-09 | 2010-08-11 | $7700.00 | Window Closed / Lapsed |