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US5233204A
Expired / Lapsed
US
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Light-emitting diode with a thick transparent layer
Assignee: Agilent Technologies Inc
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Filing: 1992-01-10
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Granted: 1993-08-03
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Expires: 2012-01-10
Abstract
Abstract A light emitting diode (LED) including a light generation region situated on a light-absorbing substrate also includes a thick transparent layer which ensures that an increased amount of light is emitted from the sides of the LED and only a minimum amount of light is absorbed by the substrate. The thickness of the transparent layer is determined as a function of its width and the critical angle at which light is internally reflected within the transparent layer. The thick transparent layer is located either above, below or both above and below the light generation region. The thick transparent layer may be made of materials and with fabrication processes different from the light generation region.
Inventors
- 👤 Robert M. Fletcher
- 👤 Kuo-Hsin Huang
- 👤 Chihping Kuo
- 👤 Jiann Yu
- 👤 Timothy D. Osentowski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:43
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/01; H10H20/011; H10H20/013
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
104 words
A light emitting diode, positioned in a medium having a refractive index, η 1 , the light emitting diode having a width, A, and comprising: a light absorbing substrate; a light generation region overlaying the substrate; a top transparent layer overlaying the light generation region, the top transparent layer having sides with a thickness, D, which is greater than a minimum thickness of 0.06 times A and wherein the top transparent layer increases the light generation efficiency of the light emitting diode by increasing an amount of light emitted from the sides and reducing an amount of light absorbed by the light absorbing substrate.
Claim 2
Dependent Claim
104 words
A light emitting diode, positioned in a medium having a refractive index, η 1 , the light emitting diode having a width, A, and comprising: a light absorbing substrate; a light generation region overlaying the substrate; a top transparent layer overlaying the light generation region, the top transparent layer having sides with a thickness, D, which is greater than a minimum thickness of 0.06 times A and wherein the top transparent layer increases the light generation efficiency of the light emitting diode by increasing an amount of light emitted from the sides and reducing an amount of light absorbed by the light absorbing substrate.
Claim 3
Dependent Claim
65 words
A light emitting diode as recited in claim 1, wherein: the top transparent layer has a refractive index, η 2 ; η 1 and η 2 define a critical angle θ c =Sin -1 (η 1 /η 2 ); the critical angle θ c ≦45°°; and the thickness, D, of the top transparent layer is less than 4 times (A * tan θ c )/2.
Claim 4
Dependent Claim
28 words
A light emitting diode as recited in claim 2, wherein the thickness, D, of the top transparent layer is substantially equal to (A * tan θ c )/2.
Claim 5
Dependent Claim
24 words
A light emitting diode as recited in claim 3, wherein the top transparent layer is selected from the group comprising GaP, GaAsP and AlGaAs.
Claim 6
Dependent Claim
65 words
A light emitting diode as recited in claim 1, wherein: the top transparent layer has a refractive index, η 2 ; η 1 and θ 2 define a critical angle θ c =Sin -1 (η 1 /η 2 ); the critical angle θ c >45°; and the thickness, D, of the top transparent layer is less than 4 times (A * tan (90°-θ c ))/2.
Claim 7
Dependent Claim
28 words
A light emitting diode as recited in claim 5, wherein the thickness, D, of the top transparent layer is substantially equal to (A * tan (90°-θ c ))/2.
Claim 8
Dependent Claim
24 words
A light emitting diode as recited in claim 6, wherein the top transparent layer is selected from the group comprising GaP, GaAsP and AlGaAs.
Claim 9
Dependent Claim
67 words
A light emitting diode, positioned in a medium having a refractive index, η 1 , the light emitting diode comprising: a light absorbing substrate; a bottom transparent layer overlaying the substrate; a confirming layer overlaying the bottom transparent layer; a light generation region overlaying the confining layer; and wherein the transparent layer is thicker than the total thickness of the light generation region and the confining layer.
Claim 10
Dependent Claim
67 words
A light emitting diode, positioned in a medium having a refractive index, η 1 , the light emitting diode comprising: a light absorbing substrate; a bottom transparent layer overlaying the substrate; a confirming layer overlaying the bottom transparent layer; a light generation region overlaying the confining layer; and wherein the transparent layer is thicker than the total thickness of the light generation region and the confining layer.
Claim 11
Dependent Claim
66 words
A light emitting diode as recited in claim 8, wherein: the light emitting diode has a width, A; the bottom transparent layer has a refractive index, η 2 ; η a and η 2 define a critical angle θ c =Sin -1 (η 1 /η 2 ); the thickness, D, of the bottom transparent layer is less than 4 times A * tan θ c .
Claim 12
Dependent Claim
28 words
A light emitting diode as recited in claim 9, wherein the thickness, D, of the bottom transparent layer is substantially equal to A * tan θ c .
Claim 13
Dependent Claim
24 words
A light emitting diode as recited in claim 10, wherein the bottom transparent layer is selected from the group comprising GaP, GaAsP and AlGaAs.
Claim 14
Dependent Claim
25 words
A light emitting diode as recited in claim 1, further comprising a bottom transparent layer between the light generation region and the light absorbing substrate.
Claim 15
Dependent Claim
61 words
A light emitting diode as recited in claim 12, wherein: the bottom transparent layer has a refractive index, η 2 ; η 1 and η 2 define a critical angle θ c =Sin -1 (η 1 /η 2 ); and the thickness, D B , of the bottom transparent layer is less than 4 times A * tan θ c .
Claim 16
Dependent Claim
30 words
A light emitting diode as recited in claim 13, wherein the thickness, D B , of the bottom transparent layer is substantially equal to A * tan θ c .
Claim 17
Dependent Claim
24 words
A light emitting diode as recited in claim 14, wherein: the top transparent layer is selected from the group comprising GaP, GaAsP and AlGaAs.
Claim 18
Dependent Claim
38 words
A light emitting diode as recited in claim 1, wherein: the light generation region is fabricated by a first process; and the top transparent layer is fabricated by a second process which is different from the first process.
Claim 19
Dependent Claim
38 words
A light emitting diode as recited in claim 8, wherein: the light generation region is fabricated by a first process; and the bottom transparent layer is fabricated by a second process which is different from the first process.
Claim 20
Dependent Claim
55 words
A light emitting diode as recited in claim 12, wherein: the light generation region is fabricated by a first process; the top transparent layer is fabricated by a second process which is different from the first process; and the bottom transparent layer is fabricated by a third process which is different from the first process.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-08-02 | 1997-02-01 | 1997-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-02 | 2001-02-01 | 2001-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-02 | 2005-02-01 | 2005-08-03 | $7700.00 | Window Closed / Lapsed |