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US5382787A Expired / Lapsed US ⏱️ 0.0 years remaining

Photoconductive material

Assignee: Kanegafuchi Chemical Industry Co Ltd
•
Filing: 1992-07-07
•
Granted: 1995-01-17
•
Expires: 2012-07-07
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Abstract

Abstract The invention provides a temperature switch material capable of detecting a very low temperature not higher than 150 K. It also provides a light switch material for detecting light in the ultraviolet region. It further provides a switch material suited for use as a substrate for thin oxide layer formation thereon. The switching material utilizes an abrupt change in photoelectric current as produced upon phase transition of SrTiO 3 at a low temperature. The photoelectric switch or temperature switch utilizes the change in photoconduction spectrum upon irradiation of SrTiO 3 with light in the 3 eV-5 eV ultraviolet region. A switch is available by varying the intensity of irradiating light thereby controlling the transition temperature.

Inventors

  • 👤 Jun Takada
  • 👤 Akihiko Nakajima
  • 👤 Yoshihisa Tawada

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-09 02:24
CPC Classifications
H; H10; H10F; H10F77/00; H10F77/10; H10F77/12; H10F30/00; H10F30/10

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 78 words
A photoconductive method comprising irradiating a substance having a perovskite structure, whose crystal structure can undergo phase transition, with a light beam having an energy in a range of 3eV to 5eV; and varying a light intensity of the light beam at an ambient temperature in a range lower than 150 K. and around a structural phase transition temperature of said substance, thereby varying a structural phase transition temperature of said substance and changing photoconductivity of said substance.
Claim 2
Dependent Claim 78 words
A photoconductive method comprising irradiating a substance having a perovskite structure, whose crystal structure can undergo phase transition, with a light beam having an energy in a range of 3eV to 5eV; and varying a light intensity of the light beam at an ambient temperature in a range lower than 150 K. and around a structural phase transition temperature of said substance, thereby varying a structural phase transition temperature of said substance and changing photoconductivity of said substance.
Claim 3
Dependent Claim 14 words
A photoconductive method according to claim 1, wherein said substance is SrTiO 3 .
Claim 4
Dependent Claim 52 words
A photoconductive method comprising changing an ambient temperature of a substance having a perovskite structure, whose crystal structure can undergo phase transition, in a range lower than 150 K. and around a structural phase transition temperature of said substance, thereby changing a photoconduction spectrum, representing a light receiving characteristic, of said substance.
Claim 5
Dependent Claim 52 words
A photoconductive method comprising changing an ambient temperature of a substance having a perovskite structure, whose crystal structure can undergo phase transition, in a range lower than 150 K. and around a structural phase transition temperature of said substance, thereby changing a photoconduction spectrum, representing a light receiving characteristic, of said substance.
Claim 6
Dependent Claim 14 words
A photoconductive method according to claim 1, wherein said substance is SrTiO 3 .

References Cited (Backward Citations)

US4400451A Cited
US4419278A Cited
JPS6234981A Cited
US4927721A Cited
US4939308A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1998-01-16 1998-07-18 1999-01-17 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 2002-01-16 2002-07-18 2003-01-17 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 2006-01-16 2006-07-18 2007-01-17 $7700.00 Window Closed / Lapsed

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