US4081764A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Zinc oxide light emitting diode
Assignee: 3M Co
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Filing: 1973-09-10
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Granted: 1978-03-28
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Expires: 1993-09-10
Abstract
Abstract A light emitting diode comprising a single crystal of high efficiency violet fluorescing zinc oxide together with an ohmic cathode and a rectifying anode secured thereto. The diode emits near band-gap radiation at room temperature when energized with low D.C. voltage. The produced light is believed to be associated with radiative recombination of free excitons.
Inventors
- 👤 Marvin H. Christmann
- 👤 Richard L. Weiher
- 👤 William C. Tait
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 01:43
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/30; H01S5/32; H10; H10H; H10H20/00; H10H20/80; H10P; H10P95/00
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
85 words
A light emitting diode comprising a crystal of high efficiency violet fluorescing zinc oxide, a substantially ohmic cathode secured to a portion of the crystal and a rectifying anode secured to another portion of the crystal, which diode emits light at room temperature when a low electrical potential is applied across said cathode and anode, wherein the zinc oxide crystal is a thin z-cut slab sectioned from a single crystalline boule and wherein the rectifying anode is secured to an oxygen face of said slab.
Claim 2
Dependent Claim
85 words
A light emitting diode comprising a crystal of high efficiency violet fluorescing zinc oxide, a substantially ohmic cathode secured to a portion of the crystal and a rectifying anode secured to another portion of the crystal, which diode emits light at room temperature when a low electrical potential is applied across said cathode and anode, wherein the zinc oxide crystal is a thin z-cut slab sectioned from a single crystalline boule and wherein the rectifying anode is secured to an oxygen face of said slab.
Claim 3
Dependent Claim
39 words
A diode according to claim 1, wherein the zinc oxide crystal is characterized by fluorescent efficiency at 77° K of not less than 0.001 and a carrier concentration of not less than 10 17 electrons per cm 3 .
Claim 4
Dependent Claim
28 words
A diode according to claim 1, wherein the substantially ohmic cathode comprises a material having a work function not appreciably greater than the work function of zinc oxide.
Claim 5
Dependent Claim
15 words
A diode according to claim 3, wherein said cathode material consists of indium or zinc.
Claim 6
Dependent Claim
21 words
A diode according to claim 3, wherein said cathode material consists of transparent conductive oxides of tin, indium or mixtures thereof.
Claim 7
Dependent Claim
17 words
A diode according to claim 1, wherein said rectifying anode comprises gold, platinum, carbon, silver or copper.
Claim 8
Dependent Claim
16 words
A diode according to claim 1, wherein the rectifying anode contains at least one point contact.
Claim 9
Dependent Claim
34 words
A diode according to claim 7, wherein the point contacts comprise a conductive paint secured to a crystal surface substantially free of destruction layers, which paint comprises gold particles dispersed in a silicate binder.
Claim 10
Dependent Claim
40 words
A diode according to claim 1, further comprising a layer of luminescent material secured to receive light emitted from the zinc oxide crystal and to emit light of a second wavelength in response to said received zinc oxide emitted light.
Claim 11
Dependent Claim
26 words
A diode according to claim 1, wherein the zinc oxide crystal has opposing major faces and the cathode and anode comprise layers evaporated onto said faces.
Claim 12
Dependent Claim
29 words
A diode according to claim 10, further comprising electrical contacts and means for holding the electrical contacts under pressure against the evaporated layers to facilitate passage of electrical current.
Claim 13
Dependent Claim
19 words
A diode according to claim 1, wherein each cathode and anode is a conductive paint, foil or evaporated film.
Claim 14
Dependent Claim
22 words
A diode according to claim 1, in which said crystal consists of a pure crystal of high efficiency violet fluorescing zinc oxide.
Claim 15
Dependent Claim
22 words
A diode according to claim 1, in which said crystal consists of an untreated crystal of high efficiency violet fluorescing zinc oxide.
Claim 16
Dependent Claim
36 words
A diode according to claim 1, wherein said crystal is further fabricated to have a pair of optically parallel and at least partially reflective faces to form a resonant cavity for the production of coherent emission.
Claim 17
Dependent Claim
60 words
A light emitting diode according to claim 1, wherein the rectifying anode comprises an array of isolated anodes on a surface of the zinc oxide crystal and the substantially ohmic cathode is secured to a portion of the crystal selected so as not to impede the emission of light from the vicinity of each of said array of isolated anodes.
Claim 18
Dependent Claim
25 words
A diode according to claim 7, wherein the point contact has an active barrier area having an average diameter of not more than 0.5 micrometers.
Claim 19
Dependent Claim
18 words
A diode according to claim 7, wherein a number of point contacts are contained within the rectifying anode.
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) | 1981-03-27 | 1981-09-26 | 1982-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-27 | 1985-09-26 | 1986-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-27 | 1989-09-26 | 1990-03-28 | $7700.00 | Window Closed / Lapsed |