US4626885A — Photosensor having impurity concentration gradient

Claim 1

Independent Claim 174 words

A photosensor comprising: a transparent electrode disposed on a light receiving side of said photosensor and formed of a transparent conductive film; and a photoconductive layer disposed on said transparent electrode, said photoconductive layer consisting of at least 5 to 30 atomic percent of hydrogen, at least one doped impurity selected from the group consisting of elements belonging to Groups II and III of the Periodic Table and the balance of amorphous silicon, a voltage being applied across said photoconductive layer so that a surface of said photoconductive layer facing said transparent electrode is at a positive potential with respect to another surface of said photoconductive layer opposite to said surface facing said transparent electrode; said at least one impurity having a concentration profile which is in a range of 0 to 5 ppm at the interface between said transparent electrode and said photoconductive layer, which does not decrease with the distance from the interface, and which is in a range of 1 to 100 ppm at said another surface of the photoconductive layer.

Claim 2

Dependent Claim 174 words

A photosensor comprising: a transparent electrode disposed on a light receiving side of said photosensor and formed of a transparent conductive film; and a photoconductive layer disposed on said transparent electrode, said photoconductive layer consisting of at least 5 to 30 atomic percent of hydrogen, at least one doped impurity selected from the group consisting of elements belonging to Groups II and III of the Periodic Table and the balance of amorphous silicon, a voltage being applied across said photoconductive layer so that a surface of said photoconductive layer facing said transparent electrode is at a positive potential with respect to another surface of said photoconductive layer opposite to said surface facing said transparent electrode; said at least one impurity having a concentration profile which is in a range of 0 to 5 ppm at the interface between said transparent electrode and said photoconductive layer, which does not decrease with the distance from the interface, and which is in a range of 1 to 100 ppm at said another surface of the photoconductive layer.

Claim 3

Dependent Claim 102 words

A photosensor according to claim 1, wherein the concentration of said selected element in said photoconductive layer is not more than 5 ppm at the interface between said transparent conductive film and said photoconductive layer, is equal to zero or increases with the distance from the interface in a region of the photoconductive layer between the interface and a middle area of the photoconductive layer and lies in a range from 1 to 100 ppm in a region between the middle area of said photoconductive layer and said another surface of said photoconductive layer opposite to said surface facing said transparent electrode.

Claim 4

Dependent Claim 44 words

A photosensor according to claim 2, wherein the concentration of said selected element in said photoconductive layer is not more than 10 ppm in a region between said interface and an area which is away from said interface by a distance of 0.5 μm.

Claim 5

Dependent Claim 96 words

A photosensor according to claim 1, wherein the concentration of said selected element in said photoconductive layer is not more than 10 ppm within a region between said interface and an area which is away by a distance x c from said interface, at said area hole current density J p being equal to an electron current density J e , and lies in a range from 1 to 100 ppm in another region between said area which is away by said distance x c from said interface and said another surface of said photoconductive layer.

Claim 6

Dependent Claim 45 words

A photosensor according to claim 1, wherein a beam landing layer is provided on said another surface of said photoconductive layer, and the intensity distribution of incident light at said transparent conductive film is detected by scanning said beam landing layer with an electron beam.

Claim 7

Dependent Claim 32 words

A photosensor according to claim 1, wherein said elements belonging to the group II comprise zinc and cadmium, and said elements belonging to the group III comprise boron, aluminum, gallium and indium.

Claim 8

Dependent Claim 40 words

A photosensor according to claim 1, wherein said at least one impurity has a concentration profile which has a higher value in a region remote from the transparent electrode than the concentration in a region proximate to the transparent electrode.

Claim 9

Dependent Claim 243 words

An image pickup tube comprising: a transparent substrate for receiving an optical image through the substrate; a transparent electrode formed on a surface of said transparent substrate and made of an optically transparent and electrically conductive material; a photoconductive layer disposed on said transparent electrode, said photoconductive layer consisting of at least 5 to 30 atomic percent hydrogen, at least one doped impurity selected from the group consisting of elements belonging to Groups II and III of the Periodic Table and the balance of amorphous silicon, a voltage being applied across said photoconductive layer so that a surface of said photoconductive layer facing said transparent electrode is at a positive potential with respect to another surface of said photoconductive layer opposite to said surface facing said transparent electrode, said at least one impurity having a concentration profile which is in a range of 0 to 5 ppm at the interface between said transparent electrode and said photoconductive layer, which does not decrease with the distance from the interface, and which is in a range of 1 to 100 ppm at said another surface of the photoconductive layer; an electron gun for emitting an electron beam toward said photoconductive layer; an electron deflector disposed between said photoconductive layer and said electron gun for deflecting said electron beam so as to scan a surface of said photoconductive layer with said electron beam; and a power source connected between said transparent electrode and said electron gun.

Claim 10

Dependent Claim 243 words

An image pickup tube comprising: a transparent substrate for receiving an optical image through the substrate; a transparent electrode formed on a surface of said transparent substrate and made of an optically transparent and electrically conductive material; a photoconductive layer disposed on said transparent electrode, said photoconductive layer consisting of at least 5 to 30 atomic percent hydrogen, at least one doped impurity selected from the group consisting of elements belonging to Groups II and III of the Periodic Table and the balance of amorphous silicon, a voltage being applied across said photoconductive layer so that a surface of said photoconductive layer facing said transparent electrode is at a positive potential with respect to another surface of said photoconductive layer opposite to said surface facing said transparent electrode, said at least one impurity having a concentration profile which is in a range of 0 to 5 ppm at the interface between said transparent electrode and said photoconductive layer, which does not decrease with the distance from the interface, and which is in a range of 1 to 100 ppm at said another surface of the photoconductive layer; an electron gun for emitting an electron beam toward said photoconductive layer; an electron deflector disposed between said photoconductive layer and said electron gun for deflecting said electron beam so as to scan a surface of said photoconductive layer with said electron beam; and a power source connected between said transparent electrode and said electron gun.

Claim 11

Dependent Claim 102 words

An image pickup tube according to claim 8, wherein the concentration of said selected element in said photoconductive layer is not more than 5 ppm at the interface between said transparent electrode and said photoconductive layer, is equal to zero or increases with the distance from the interface in a region of the photoconductive layer between the interface and a middle area of the photoconductive layer and lies in arange from 1 to 100 ppm in a region between the middle area of said photoconductive layer said said another surface of said photoconductive layer opposite to said surface facing said transparent electrode.

Claim 12

Dependent Claim 46 words

A image pickup tube according to claim 9, wherein the concentration of said selected element in said photoconductive layer is not more than 10 ppm in a region between said interface and an area which is away from said interface by a distance of 0.5 μm.

Claim 13

Dependent Claim 98 words

An image pickup tube according to claim 8, wherein the concentration of said selected element in said photoconductive layer is not more than 10 ppm without a region between said interface and an area which is away by a distance x c from said interface, at said area hole current density J p being equal to an electron current density J e , and lies in a range from 1 to 100 ppm in another region between said area which is away by said distance x c from said interface and said another surface of said photoconductive layer.

Claim 14

Dependent Claim 37 words

An image pickup tube according to claim 8, wherein at least one of a thin semiconductor layer of n-type conductivity and a thin transparent dielectric layer is interposed between said photoconductive layer and said transparent conductive electrode.

Claim 15

Dependent Claim 46 words

An image pickup tube according to claim 8, wherein a beam landing layer is provided on said another surface of said photoconductive layer, and the intensity distribution of incident light at said transparent electrode is detected by scanning said beam landing layer with an electron beam.

Claim 16

Dependent Claim 34 words

An image pickup tube according to claim 8, wherein said elements belonging to the group II comprise zinc and cadmium, and said elements belonging to the group III comprise boron, aluminum, gallium and indium.

Claim 17

Dependent Claim 42 words

An image pickup tube according to claim 8, wherein said at least one impurity has a concentration profile which has a higher value in a region remote from the transparent electrode than the concentration in a region proximate to the transparent electrode.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-12-01	1990-06-02	1990-12-02	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-12-01	1994-06-02	1994-12-02	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-12-01	1998-06-02	1998-12-02	$7700.00	Window Closed / Lapsed

Photosensor having impurity concentration gradient

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag