US3800194A - Photoconductive target of an image tube - Google Patents

Photoconductive target of an image tube Download PDF

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Publication number
US3800194A
US3800194A US00347663A US34766373A US3800194A US 3800194 A US3800194 A US 3800194A US 00347663 A US00347663 A US 00347663A US 34766373 A US34766373 A US 34766373A US 3800194 A US3800194 A US 3800194A
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US
United States
Prior art keywords
photo
conductive layer
target
film
image pickup
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US00347663A
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English (en)
Inventor
E Maruyama
T Hirai
K Inao
N Goto
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Hitachi Ltd
Japan Broadcasting Corp
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Hitachi Ltd
Japan Broadcasting Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/36—Photoelectric screens; Charge-storage screens
    • H01J29/39—Charge-storage screens
    • H01J29/45—Charge-storage screens exhibiting internal electric effects caused by electromagnetic radiation, e.g. photoconductive screen, photodielectric screen, photovoltaic screen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S257/00—Active solid-state devices, e.g. transistors, solid-state diodes
    • Y10S257/917—Plural dopants of same conductivity type in same region

Definitions

  • ABSTRACT A target for an image pickup tube comprising a lighttransmitting conductive layer supported on a light- IMAGE TUBE [75] Inventors: Eiichi Maruyama, Kodaira; Tadaaki Hirai, Koganei; Kiyohisa Inao, l-lachioji; Naohiro Goto, Machida, all of Japan [73] Assignees: Hitachi, Ltd.; Nippon Hoso Kyokai, both of Tokyo, Japan [22] Filed: Apr. 4, 1973 [21] Appl. No.: 347,663
  • 317/241 transmitting substrate and a photoconductive layer with rectifying contact at least at one of its sides; in which the photoconductive layer has a portion 1,000 A or thicker which comprises a multiplicity of thin films of two or more different materials with different photoconductive characteristics, each having a thickness of not more than 100 A, the thin films of the different materials being laid alternately one on another,
  • the present invention relates to a target of animage pickup tube or more in particular to a target of an image pickup tube of vidicon type utilizing the rectifying contact of a photoconductive semiconductor.
  • the materials of the target for the image pickup tube now in commercial use include photoconductive semiconductors such as Sb S PbO and Si.
  • a target of Sb S is characterized by an ohmic contact, while those made of PbO or Si generally have a rectifying contact or is of a PN junction type.
  • the target with the rectifying contact or PN junction has many advantages including the fact that they allow less dark current, is higher in sensitivity and greater in response speed than the target with an ohmic contact.
  • the manufacture of an image pickup tube with a PN junction of single crystal such as a vidicon with Si target requires highly complex processes, and also it is very difficult to remove an imperfection of a picture attributable to the defects of a crystal bulk or unsatisfactory processes.
  • a target of a thin film with a rectifying contact is manufactured by comparatively simple processes, but it is not an easy matter to achieve a rectifying contact which is used successfully for a vidicon target, the known materials suitable for such a purpose being limited to PhD and few others including selenium and its compounds.
  • a plurality of different component elements are deposited simultaneously from a plurality of sources of evaporation.
  • the plurality of sources are located at different positions relative to the substrate and therefore the composition of the resulting layer on the substrate is not necessarily uniform at every point on the substrate.
  • the inventors have discovered that the alternate deposition of a multiplicity of thin films of different substances one on another makes it possible to obtain a photoconductive layer with a photoconductive characteristic quite similar to that of a material resulting from the uniform mixing of such substances.
  • the resulting characteristic is the sum of the different photoconductive characteristics involved. If, however, the thickness of each component thin film is sufficiently small and the laminated structure consists of a multiplicity of such thin films deposited alternately one on another, the resulting photoconductive characteristic is intermediate with respect to those of the component thin films.
  • the target of the image pickup tube comprises a light-transmitting substrate, a light-transmitting conductive layer and a photoconductive layer deposited on the light-transmitting conductive layer and including a part 1,000 A or thicker consisting of at least two thin films of different photo-conductive characteristics alternately laid one on another, each of the thin films being A or thinner said photo-conductive layer having at least one rectifying contact on its surface.
  • FIG. 1 is a diagram showing a section of a target for the image pickup tube according to the present invention
  • FIG. 2 is a diagram showing the spectral sensitivity of a conventional photo-conductive double layer consisting of Se and AS253;
  • FIG. 3 is a diagram showing the spectral sensitivity ofa layer consisting of Se and AS253 used for the target for the image pickup tube according to the present invention.
  • FIGS. 4 to 6 are diagrams showing sections of embodiments of the present invention.
  • EMBODIMENT 1 An embodiment of the invention is illustrated in F IG. 1, in which reference numeral 1 shows a glass substrate, numeral 2 a lighttransmitting conductive layer, and numeral 3 a photo-conductive layer.
  • the photoconductive layer 3 of about 3 microns thick is made by depositing by evaporation a multiplicity of selnium films each about 20 A and As Se films each about 7 A alternately one on another in a vacuum of 5 X 10 Torr.
  • a rectifying contact is formed between the lighttransmitting conductive layer 2 and the photoconductive layer 3.
  • a photo-conductive layer 3 consisting of only a selenium film has a superior rectifying contact but has the disadvantage of insufficient sensitivity to light of long wavelength.
  • the photo-conductive layer 3 is formed of only As se by contrast, a high sensitivity to red light is obtained but it is impossible to form a superior rectifying contact.
  • the photo-conductive layer 3 were made of comparatively thick Se and As Se films of, say, 5,000 A each, two peaks of spectral sensitivity corresponding to those of the individual component films of Se and As Se respectively would be observed as shown in FIG. 2.
  • the photo-conductive layer 3 according to the present invention which comprises a multiplicity of comparatively thin Se and As Se alternate films of, say, 50 A in thickness each having its peak of spectral sensitivity intermediate with respect to the two hypothetical peaks which otherwise might occur separately for the two component film elements.
  • the photo-conductive layer 3 has similar characteristics as if Se and As se are mixed uniformly. Such similarity is achieved only when the thickness of each film of Se and As Se is approximately 100 A or less.
  • the construction of the photo-conductive layer according to this embodiment to achieve a photo-conductive layer superior in dark current characteristic, after image characteristic and sensitivity to long wavelength light as shown in Table 1 without adversely affecting the rectifying characteristic.
  • the above mentioned multi-layer construction is not necessarily required all over its total thickness. Most of the energy of light entering the photo-conductive layer is absorbed at its portion within the depth of several thousands of A from the surface thereof. Therefore, the portion of the layer as thick as l,000 A or more from the surface has a controlling effect upon the spectral sensitivity of the photo-conductive layer.
  • the photo-conductive layer with the above mentioned construction is to be used for a target of the image pickup tube, its dark current characteristic, after image characteristic, lag characteristic as well as the spectral sensitivity are required to be maintained at a satisfactory level for the image pickup tube.
  • a desirable construction for the target of an image pickup tube is of the rectifying contact type. Since the characteristic of the target of the rectifying contact type largely depends upon the shape ofthe rectifying barrier, the portion of the photoconductive multi-layer for controlling the spectral sensitivity must be so selected as not to adversely affect the other characteristics of the photo-conductive layer. To achieve maximum utilization of incident light, it is recommended that the multi-layer portion of the photoconductive layer be located as near to the plane of incidence as possible so far as the effect of the rectifying barrier is not reduced.
  • the photo-conductive layer used as a target for an image pickup tube generally has the thickness of 2 to 20 microns, and it is possible, by providing a portion of the photo-conductive layer as thick as 1,000 A for controlling the spectral sensitivity of the photo-conductive layer, to limit the function of such portion to the controlling of the spectral sensitivity without any substantial effect upon the lag, after image and dark current characteristics of the photo-conductive layer.
  • reference numeral 4 denotes a glass substrate, numeral 5 a light-transmitting conductive layer,
  • a photo-conductive layer approximately 2 microns thick consisting of a multiplicity of selenium films each about 5 A thick and CdSe films each about 20 A thick alternately deposited one on another.
  • Reference numeral 7 shows a CdTe film with a thickness of approximately 1,000 A.
  • a rectifying contact is interposed between the photo-conductive layer 6 and the CdTe film 7.
  • a photo-conductive layer consisting of only selenium films develops no sufficient sensitivity to light of long wavelengths, while one with only CdSe films does not satisfy the requirements for rectifying contact.
  • the employment of a multi-layer as represented by the photoconductive layer 6 consisting of alternately deposited multiplicity of selenium and CdSe films makes it possible to obtain a target superior both in rectifying contact and in sensitivity to long wavelength as is apparent from Table 2.
  • CdTe may be replaced by ZnS, CdS, ZnSe, CdSe or a mixture of any ones of them which has a property similar to that of CdTe.
  • FIG. 5 A third embodiment of the invention is shown in FIG. 5.
  • reference numeral 8 shows a glass substrate, numeral 9 a light-transmitting conductive layer, the numeral 10 a film of MnF2 200A thick.
  • the interposition of the insulating material MnF between the light-transmitting conductive layer 9 and the selenium film 11 permits the reverse breakdown voltage of the rectifying contact between the light-transmitting conductive layer 9 and the selenium film 11 to be increased.
  • the thickness of the insulating film may be in the range from 10 to 1,000 A.
  • the selenium film 11 which is approximately 3 microns in thickness has a central portion 12 approximately 1,000 A thick including a multiplicity of selenium films each about 20 A and tellurium films each about 12 A alternately laid one on another.
  • the Sb S film 13 may be deposited by evaporation in a vacuum of 1 X 10 Torr. or thereabouts, a porous Sb S film deposited by evaporation in an argon gas of about 5 X 10 Torr. is more effective for the purpose of effective landing of electron beams.
  • the central portion 12 in the form of a multi-layer is such that an improved sensitivity to red light is obtained as shown in Table 3 without adversely affecting the rectifying contact formed of the light-transmitting conductive layer 9, insulating film and the selenium film 11.
  • FIG. 6 shows a glass substrate, numeral 15 a light-transmitting conductive layer, numeral 16 a ZnSe film approximately 500 A thick, and numeral 17 a photo-conductive layer about 3 microns thick which comprises a multiplicity of selenium films each about 40 A and arsenic films each about 5 A alternately laid one on another.
  • the superior rectifying contact between the ZnSe film 16 and photoconductive layer 17 is also achieved by using a ZnS or CdSe film of the same thickness in place of the ZnSe film.
  • an insulating film may be inserted on the side of the rectifying contact of the photo-conductive layer in order to improve the breakdown voltage of the rectifying contact in the reverse direction in the preceding embodiment.
  • the photoconductive layer 17 is provided with a central multilayer portion 18 about 2,000 A thick comprising a multiplicity of selenium films each about A, arsenic films each about 5 A and tellurium films each about 30 A which are deposited alternately one on another.
  • An Sb- S film 19 about 1,000 A thick is provided on the photowonductive layer 17 to improve the landing of the scanning electron beams.
  • the presence of the tellurium films in the layer 113 permits the sensitivity to red light to be improved as shown in Table 4 without adversely affecting the advantage of the rectifying contact.
  • a photo-conductive target for an image pickup tube comprising a light-transmitting substrate, a lighttransmitting conductive layer deposited on said lighttransmitting substrate and a photo-conductive layer deposited on said light-transmitting conductive layer, said photo-conductive layer containing selenium and including a portion not less than 1,000 A thick, said portion of said photo-conductive layer consisting of a multiplicity of thin films of at least two different materials with different photo-conductive characteristics, each having the thickness of A or less, said thin films being laid alternately one on another.
  • a photo-conductive target for an image pickup tube further comprising one semiconductor layer selected from the group consisting of ZnS, CdS, ZnSe, CdSe, CdTe and a mixture thereof deposited on said photo-conductive layer, a rectifying contact being formed by said semiconductor layer and said photo-conductive layer.
  • a photo-conductive target for an image pickup tube in which said lighttransmitting layer and said photo-conductive layer constitute a rectifying contact.
  • a photo-conductive target for an image pickup tube in which an insulating thin film with the thickness from 10 A to 1,000 A and comprising one selected from the group consisting of ZnS, PbF MnF CaF MgF A1 0 SiO and AS283 is provided adjacent to that side of said photo-conductive layer which has said rectifying contact.
  • a photo-conductive target for an image pickup tube in which an insulating thin film with the thickness from 10 A to 1,000 A and comprising one selected from the group consisting of ZnS,

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Light Receiving Elements (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
US00347663A 1972-04-07 1973-04-04 Photoconductive target of an image tube Expired - Lifetime US3800194A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47034359A JPS5240809B2 (ro) 1972-04-07 1972-04-07

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US3800194A true US3800194A (en) 1974-03-26

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US (1) US3800194A (ro)
JP (1) JPS5240809B2 (ro)
DE (1) DE2316669C3 (ro)
FR (1) FR2179253B1 (ro)
GB (1) GB1383159A (ro)
NL (1) NL157746B (ro)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3971932A (en) * 1974-12-02 1976-07-27 Varo, Inc. Apparatus for enhancing the long wavelength response of photodetectors
US3990095A (en) * 1975-09-15 1976-11-02 Rca Corporation Selenium rectifier having hexagonal polycrystalline selenium layer
US4007395A (en) * 1974-06-21 1977-02-08 Hitachi, Ltd. Target structure for use in photoconductive image pickup tubes
US4007473A (en) * 1974-06-21 1977-02-08 Hitachi, Ltd. Target structures for use in photoconductive image pickup tubes and method of manufacturing the same
US4068253A (en) * 1975-08-20 1978-01-10 Matsushita Electric Industrial Co., Ltd. Photoconductor element and method of making the element
US4128844A (en) * 1974-08-01 1978-12-05 Robert Bosch Gmbh Camera tube target structure exhibiting greater-than-unity amplification
US4266334A (en) * 1979-07-25 1981-05-12 Rca Corporation Manufacture of thinned substrate imagers
EP0031663A2 (en) * 1979-12-14 1981-07-08 Hitachi, Ltd. Photoelectric device
EP0067015A2 (en) * 1981-05-29 1982-12-15 Hitachi, Ltd. Photoconductive film
US4445131A (en) * 1980-11-10 1984-04-24 Hitachi, Ltd. Photoconductive image pick-up tube target
US4554478A (en) * 1980-01-21 1985-11-19 Hitachi, Ltd. Photoelectric conversion element
US5198673A (en) * 1992-01-23 1993-03-30 General Electric Company Radiation image detector with optical gain selenium photosensors
US5587621A (en) * 1994-02-09 1996-12-24 U.S. Philips Corporation Image intensifier tube

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5261984A (en) * 1976-08-20 1977-05-21 Hitachi Ltd Production of photoelectric converting device
JPS6051774B2 (ja) * 1976-11-17 1985-11-15 株式会社日立製作所 撮像管タ−ゲツト
JPS5832454B2 (ja) * 1979-06-07 1983-07-13 日本放送協会 光導電性タ−ゲツト
JP2753264B2 (ja) * 1988-05-27 1998-05-18 株式会社日立製作所 撮像管
DE4445894C2 (de) * 1994-12-22 1996-10-02 Daimler Benz Ag Bildaufnahmesystem
DE102007025600B4 (de) * 2007-05-31 2009-05-28 Schott Ag Interferenzfilter und Verfahren zu dessen Herstellung

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3127545A (en) * 1960-12-23 1964-03-31 Gen Telephone & Elect Rectifier
US3130137A (en) * 1959-10-14 1964-04-21 Nippon Electric Co Manufacture of selenium rectifier cell
US3439240A (en) * 1966-07-29 1969-04-15 Int Rectifier Corp Selenium rectifier
US3590253A (en) * 1969-06-30 1971-06-29 Westinghouse Electric Corp Solid-state photoconductor-electroluminescent image intensifier
US3711719A (en) * 1970-11-20 1973-01-16 Westinghouse Electric Corp Storage amplifier screen
US3755002A (en) * 1971-04-14 1973-08-28 Hitachi Ltd Method of making photoconductive film

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE545266A (ro) * 1955-02-18
JPS4216978Y1 (ro) * 1964-12-15 1967-09-30
US3569763A (en) * 1966-02-14 1971-03-09 Tokyo Shibaura Electric Co Multilayer photoconductive device having adjacent layers of different spectral response
JPS4531537Y1 (ro) * 1969-11-06 1970-12-03

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3130137A (en) * 1959-10-14 1964-04-21 Nippon Electric Co Manufacture of selenium rectifier cell
US3127545A (en) * 1960-12-23 1964-03-31 Gen Telephone & Elect Rectifier
US3439240A (en) * 1966-07-29 1969-04-15 Int Rectifier Corp Selenium rectifier
US3590253A (en) * 1969-06-30 1971-06-29 Westinghouse Electric Corp Solid-state photoconductor-electroluminescent image intensifier
US3711719A (en) * 1970-11-20 1973-01-16 Westinghouse Electric Corp Storage amplifier screen
US3755002A (en) * 1971-04-14 1973-08-28 Hitachi Ltd Method of making photoconductive film

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4007395A (en) * 1974-06-21 1977-02-08 Hitachi, Ltd. Target structure for use in photoconductive image pickup tubes
US4007473A (en) * 1974-06-21 1977-02-08 Hitachi, Ltd. Target structures for use in photoconductive image pickup tubes and method of manufacturing the same
US4128844A (en) * 1974-08-01 1978-12-05 Robert Bosch Gmbh Camera tube target structure exhibiting greater-than-unity amplification
US3971932A (en) * 1974-12-02 1976-07-27 Varo, Inc. Apparatus for enhancing the long wavelength response of photodetectors
US4068253A (en) * 1975-08-20 1978-01-10 Matsushita Electric Industrial Co., Ltd. Photoconductor element and method of making the element
US3990095A (en) * 1975-09-15 1976-11-02 Rca Corporation Selenium rectifier having hexagonal polycrystalline selenium layer
US4266334A (en) * 1979-07-25 1981-05-12 Rca Corporation Manufacture of thinned substrate imagers
EP0031663A2 (en) * 1979-12-14 1981-07-08 Hitachi, Ltd. Photoelectric device
EP0031663A3 (en) * 1979-12-14 1982-04-21 Hitachi, Ltd. Photoelectric device
US4554478A (en) * 1980-01-21 1985-11-19 Hitachi, Ltd. Photoelectric conversion element
US4445131A (en) * 1980-11-10 1984-04-24 Hitachi, Ltd. Photoconductive image pick-up tube target
EP0067015A2 (en) * 1981-05-29 1982-12-15 Hitachi, Ltd. Photoconductive film
EP0067015A3 (en) * 1981-05-29 1983-02-09 Hitachi, Ltd. Photoconductive film
US5198673A (en) * 1992-01-23 1993-03-30 General Electric Company Radiation image detector with optical gain selenium photosensors
US5587621A (en) * 1994-02-09 1996-12-24 U.S. Philips Corporation Image intensifier tube

Also Published As

Publication number Publication date
DE2316669C3 (de) 1979-11-08
DE2316669B2 (ro) 1979-03-15
NL7304822A (ro) 1973-10-09
JPS5240809B2 (ro) 1977-10-14
GB1383159A (en) 1975-02-05
DE2316669A1 (de) 1973-10-25
JPS48102919A (ro) 1973-12-24
FR2179253B1 (ro) 1978-03-03
NL157746B (nl) 1978-08-15
FR2179253A1 (ro) 1973-11-16

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