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US5446286A
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US
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Ultra-fast detectors using doped nanocrystal insulators
Assignee: Nanocrystals Technology LP
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Filing: 1994-08-11
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Granted: 1995-08-29
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Expires: 2014-08-11
Abstract
Abstract An efficient and ultrafast sensor for X-ray and UV radiation based on doped nanocrystals. These doped nanocrystals consist preferably of impurity-activator doped wide band gap II-VI semiconductors. They yield high efficiency and short recombination time radiation-sensitive phosphors which in response to radiation emit visible light easily detected by conventional sensors such as Si sensors. The combination of pulsed UV/X-ray sources with efficient and ultrafast sensors will yield sensors with increased signal to noise ratio. In a preferred embodiment, thin films of doped nanocrystals are used for generating visible radiation, which can be imaged with a conventional Si-based camera. Other applications also include the use of doped nanocrystals of piezoelectric materials to sense pressure, of pyroelectric materials to sense heat, and of ferroelectric materials to sense electric fields.
Inventors
- 👤 Rameshwar N. Bhargava
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 13:36
CPC Classifications
H; H10; H10F; H10F77/00; H10F77/10; H10F77/12; H10F77/123; H10F77/1233; G; G01; G01L; G01L1/00; G01L1/16; G01T; G01T1/00; G01T1/16; G01T1/20
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
61 words
A solid-state sensor comprising: (a) a layer of doped nanocrystals doped with an activator, (b) said doped nanocrystals having an energy band structure due to quantum confinement, (c) said activator having atomic energy levels such that excited carriers can transfer to said atomic energy levels and upon recombination will generate photons, (d) means for detecting the photons generated by the activator.
Claim 2
Dependent Claim
61 words
A solid-state sensor comprising: (a) a layer of doped nanocrystals doped with an activator, (b) said doped nanocrystals having an energy band structure due to quantum confinement, (c) said activator having atomic energy levels such that excited carriers can transfer to said atomic energy levels and upon recombination will generate photons, (d) means for detecting the photons generated by the activator.
Claim 3
Dependent Claim
24 words
A solid-state sensor as claimed in claim 1, wherein the doped nanocrystals comprise separated particles having a particle size smaller than about 100 Å.
Claim 4
Dependent Claim
27 words
A solid-state sensor as claimed in claim 2, wherein the doped nanocrystals are of materials selected from the group consisting of wide band gap semiconductors and insulators.
Claim 5
Dependent Claim
36 words
A solid-state sensor as claimed in claim 3, wherein the doped nanocrystal materials are selected from the group consisting of ZnO, ZnS, ZnSe, CdS, CdSe, Y 2 O 3 , Y 2 OS, PbS, and PbO.
Claim 6
Dependent Claim
25 words
A solid-state sensor as claimed in claim 3, wherein the activators are selected from the group consisting of rare earth ions and transition metal ions.
Claim 7
Dependent Claim
33 words
A solid-state sensor as claimed in claim 5, wherein the photons generated by the activators are in the visible spectral range, and the means for detecting the photons comprises a visible light detector.
Claim 8
Dependent Claim
18 words
A solid-state sensor as claimed in claim 6, wherein the visible light detector is Si-based or III-V compound-based.
Claim 9
Dependent Claim
27 words
A solid-state sensor as claimed in claim 1, wherein the doped nanocrystals are in the form of a thin layer positioned close to the means for detecting.
Claim 10
Dependent Claim
22 words
A solid-state sensor as claimed in claim 8, wherein the means for detecting is a Si detector or a Si CCD camera.
Claim 11
Dependent Claim
21 words
A solid-state sensor as claimed in claim 9 for UV detection, wherein the thin layer is less than 1000 Å thick.
Claim 12
Dependent Claim
21 words
A solid-state sensor as claimed in claim 9 for X-ray detection, wherein the thin layer is less than 10,000 Å thick.
Claim 13
Dependent Claim
81 words
A solid-state X-ray detector comprising: (a) a layer of doped nanocrystals of a high Z material doped with an activator, (b) said doped nanocrystals having an energy band structure due to quantum confinement and producing excited carriers in response to incident X-rays, (c) said activator having atomic energy levels such that excited carriers can transfer to said atomic energy levels and upon recombination will generate visible photons, (d) a visible light detector means for detecting the photons generated by the activator.
Claim 14
Dependent Claim
81 words
A solid-state X-ray detector comprising: (a) a layer of doped nanocrystals of a high Z material doped with an activator, (b) said doped nanocrystals having an energy band structure due to quantum confinement and producing excited carriers in response to incident X-rays, (c) said activator having atomic energy levels such that excited carriers can transfer to said atomic energy levels and upon recombination will generate visible photons, (d) a visible light detector means for detecting the photons generated by the activator.
Claim 15
Dependent Claim
17 words
A solid-state detector as claimed in claim 12, wherein the high Z material is PbO or PbS.
Claim 16
Dependent Claim
16 words
A solid-state detector as claimed in claim 12, wherein the activator is a rare earth element.
Claim 17
Dependent Claim
128 words
An X-ray imaging device comprising: (a) an X-ray beam source comprising macropulses each comprising short micropulses in the picosec. range, (b) an object to be imaged in the beam path, each point of the object scattering the X-ray micropulses, (c) a solid state screen positioned to intercept the scattered micropulses, said screen comprising a layer of doped nanocrystals of a high Z material doped with an activator, said doped nanocrystals having an energy band structure due to quantum confinement and producing excited carriers in response to incident X-rays, said activator having atomic energy levels such that excited carriers can transfer to said atomic energy levels and upon recombination will emit visible photons, (d) means for detecting the photons and for determining the screen locations where photons are emitted.
Claim 18
Dependent Claim
128 words
An X-ray imaging device comprising: (a) an X-ray beam source comprising macropulses each comprising short micropulses in the picosec. range, (b) an object to be imaged in the beam path, each point of the object scattering the X-ray micropulses, (c) a solid state screen positioned to intercept the scattered micropulses, said screen comprising a layer of doped nanocrystals of a high Z material doped with an activator, said doped nanocrystals having an energy band structure due to quantum confinement and producing excited carriers in response to incident X-rays, said activator having atomic energy levels such that excited carriers can transfer to said atomic energy levels and upon recombination will emit visible photons, (d) means for detecting the photons and for determining the screen locations where photons are emitted.
Claim 19
Dependent Claim
30 words
An X-ray imaging device as claimed in claim 15, wherein the means for detecting and for determining of claim element d comprises gating circuitry connected to the solid state screen.
Claim 20
Dependent Claim
30 words
An X-ray imaging device as claimed in claim 15, wherein the means for detecting and for determining of claim element d comprises coincidence circuitry connected to the means for detecting.
Claim 21
Dependent Claim
18 words
An X-ray imaging device was claimed in claim 17, wherein the means for detecting comprises a CCD camera.
Claim 22
Dependent Claim
30 words
An X-ray imaging device as claimed in claim 18, further comprising a high resolution display device connected to the CCD camera and synchronous timing circuitry connected to the display device.
Claim 23
Dependent Claim
80 words
A solid-state sensor comprising: (a) a layer comprising doped nanocrystals doped with an activator, (b) said doped nanocrystals having an energy band structure due to quantum confinement, (c) said activator having atomic energy levels such that excited carriers can transfer to said atomic energy levels and upon recombination will generate visible photons, (d) means for detecting the photons generated by the activator, (e) said doped nanocrystals creating excited carriers in response to UV, X-rays, pressure, heat, or an electric field.
Claim 24
Dependent Claim
80 words
A solid-state sensor comprising: (a) a layer comprising doped nanocrystals doped with an activator, (b) said doped nanocrystals having an energy band structure due to quantum confinement, (c) said activator having atomic energy levels such that excited carriers can transfer to said atomic energy levels and upon recombination will generate visible photons, (d) means for detecting the photons generated by the activator, (e) said doped nanocrystals creating excited carriers in response to UV, X-rays, pressure, heat, or an electric field.
Claim 25
Dependent Claim
17 words
A solid-state sensor as claimed in claim 20, wherein the doped nanocrystals comprise a piezoelectric material coating.
Claim 26
Dependent Claim
23 words
A solid-state sensor as claimed in claim 21, wherein the doped nanocrystals are each coated with a thin layer of a charge-generating material.
Claim 27
Dependent Claim
18 words
A solid-state sensor as claimed in claim 21, wherein the doped nanocrystals are embedded in a optical fiber.
Claim 28
Dependent Claim
19 words
A solid-state sensor as claimed in claim 21, wherein the doped nanocrystals are embedded in a flexible pressure-responsive matrix.
Claim 29
Dependent Claim
17 words
A solid-state sensor as claimed in claim 20, wherein the doped nanocrystals comprise a ferroelectric material coating.
Claim 30
Dependent Claim
17 words
A solid-state sensor as claimed in claim 20, wherein the doped nanocrystals comprise a pyroelectric material coating.
References Cited (Backward Citations)
EP0467044A2
Cited
US5293050A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-08-28 | 1999-02-27 | 1999-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-28 | 2003-02-27 | 2003-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-28 | 2007-02-27 | 2007-08-29 | $7700.00 | Window Closed / Lapsed |