US3912962A - Colour pickup tube having a false signal preventing film - Google Patents

Colour pickup tube having a false signal preventing film Download PDF

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Publication number
US3912962A
US3912962A US448460A US44846074A US3912962A US 3912962 A US3912962 A US 3912962A US 448460 A US448460 A US 448460A US 44846074 A US44846074 A US 44846074A US 3912962 A US3912962 A US 3912962A
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United States
Prior art keywords
false signal
preventing film
signal preventing
filter
pickup tube
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Expired - Lifetime
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US448460A
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English (en)
Inventor
Samuro Nobutoki
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Hitachi Ltd
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Hitachi Ltd
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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
    • H01J29/86—Vessels; Containers; Vacuum locks
    • H01J29/89—Optical or photographic arrangements structurally combined or co-operating with the vessel
    • H01J29/898—Spectral filters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/89—Optical components associated with the vessel
    • H01J2229/8913—Anti-reflection, anti-glare, viewing angle and contrast improving treatments or devices
    • H01J2229/8916—Anti-reflection, anti-glare, viewing angle and contrast improving treatments or devices inside the vessel

Definitions

  • ABSTRACT [30] Foreign Application Priority Data In a vidicon type pickup tube for use in single tube Apr. 11, 1973 Japan 48-40456 type or two tube type 01 ur television camera tems comprising a transparent glass window, an opti- [52] US. Cl. 313/371; 313/388; 313/390 cal colour analyzing stripe filter formed on one sur- [51] Int. C1. H01J 29/36 face of the glass window, and a false signal preventing Field of Seal'dl film made of a layer of transparent solid substance and 390 formed on the surface of the stripe filter, the false signal preventing film extends to a given extent beyond [56] References Cited or terminates short of the periphery of the stripe filter.
  • This invention relates to a pickup tube for use in single tube type or two tube type colour television camera systems (hereinafter merely referred to as a filter encoded pickup tube) and more particularly to a vidicon type pickup tube in which an optical colour analyzing stripe filter is provided on one side surface of a transparent glass window.
  • the filter encoded pickup tubes are mentioned the filter encoded pickup tubes.
  • the filter encoded pickup tube is provided with an optical colour analyzing stripe filter on the rear surface of a transparent glass window directed to an object, and a transparent electroconductive film and a photoconductive film which are laminated on the stripe filter.
  • the optical colour analyzing stripe filter comprises two filter components, one of them including an alternate arrangement of a filter element provided with fine stripes transmitting light of substantially all colours from the object and a filter element provided with fine stripes essentially preventing transmission of red light among light of various colours from the object.
  • the other filter component includes an alternate arrangement of a filter element provided with fine stripes transmitting light of substantially of all colours from the object and a stripe element provided with fine stripes essentially preventing transmission of blue light among light of various colours from the object.
  • the light image of the object projected upon the photoconductive film through the transparent glass window is sampled at a spatial frequency of the optical colour analyzing stripe filter so that when the light image is scanned with an electron beam, a multiplex colour signal is produced having two carrier waves caused by the difference in the spacing between the filter element that blocks the red light and the filter element that blocks the blue light of said two filter components.
  • optical colour analyzing strip filter comprises a dichroic filter generally formed by vapour desposition technique
  • the thickness of the dichroic filter is of the order of 1 micron the thickness of the portion where two filters are superposed one upon another amounts to a maximum of about 3 microns with the result that the surface of the glass plate on which the optical colour analyzing stripe filter is formed becomes irregular. If the transparent electroconductive film and the photoconductive film were formed directly on such an irregular surface these films would also be irregular.
  • an irregular photoconductive film is incorporated into a colour pickup tube an abnormal condition of the signal current will result due to an abnormal surface electric field corresponding to the irregularity of the pickup surface.
  • the optical colour analyzing stripe filter is coated with a false signal preventing film consisting of a layer of transparent solid substance such as a glass layer or a Si0 layer so as to eliminate the irregularity on the surface of the optical colour analyzing stripe filter.
  • the surface of the filter is made more flat by polishing, chemical etching, or the polishing and chemical etching in combination.
  • the vidicon type colour pickup tube it is necessary to form a transparent conductive film on the inner surface of the transparent glass window so as to derive out the signal produced in the photoconductive film and to permit the incident rays to reach the photoconductive surface.
  • a so-called NESA film is used as the transparent conductive film.
  • the NESA film consists essentially and mainly of tin oxide prepared by spraying onto a glass substrate a fine spray of a solution containing a solute consisting essentially of stannic chloride and then decomposing and oxidizing the stannic chloride.
  • a solution containing a solute consisting essentially of stannic chloride and then decomposing and oxidizing the stannic chloride.
  • To form the film it is essential to heat the glass substrate at a temperature of about 500C so that due to the difference in the coefficient of thermal expansion of a structure formed on the glass substrate and the false signal preventing film applied onto the structure there is a tendency of peeling off the false signal preventing film or cracking thereof. For this reason, the NESA film also tends to peel off or crack.
  • the formation of the peel off and cracks of the false signal preventing film on the substrate which are caused by the difference in the coefficient of thermal expansion depends upon the state of two dimensional spreading of the film on the surface of the glass substrate. More particularly, when the film is formed on the portion of the face plate of the pickup tube where the optical colour analyzing stripe filter is disposed or extends in a predetermined area of the mirror surface of the transparent glass window of the pickup tube, it was confirmed that there is no peeling off and cracking of the false signal preventing film caused by the heat treatment of the NESA film. It is believed that the coarse or irregular surface of the optical colour analyzing stripe filter functions to prevent the peeling off of the false signal prevenang film.
  • the peeling off and cracking of the false signal preventing film can be precluded by decreasing the area in which the film extends on the glass mirror surface, thereby correspondingly decreasing the adhering area by a small bonding force between the film and the mirror surface.
  • the vidicon type colour pickup tube of this invention is characterized in that it comprises an optical colour analyzing stripe filter formed on the rear surface of a transparent glass window, and a false signal preventing film of a transparent solid substance and formed on the rear surface of the optical colour analyzing stripe filter and that the false signal preventing film is formed to extend to a mirror surface in a predetermined area of the transparent glass window or not to extend to the mirror surface of the transparent glass window.
  • FIG. 1 is a diagrammatic representation of one example of a vidicon type pickup tube
  • FIG. 2 is a perspective view of an optical colour analyzing stripe filter
  • FIG. 3. is a diagram showing an actual construction of the optical colour analyzing stripe filter
  • FIG. 4 is a perspective view of the optical colour analyzing stripe filter shown in FIG. 3;
  • FIGS. 5a and 5b are partial sectional views showing certain steps of preparing the colour analyzing stripe filter
  • FIGS. 6a through 6d show examples of the relationship between the optical colour analyzing stripe filter and the false signal preventing film
  • FIGS. 7a, 7b and 7c are partial sectional views showing different types of the combinations of the optical colour analyzing stripe filter and the false signal preventing film;
  • FIG. 8A shows a plan view of one embodiment of the pickup tube of this invention
  • FIG. 8B is a sectional view of the pickup tube shown in FIG. 8A taken along a line VIIIB-VIIIB;
  • FIG. 9A shows a plane view of another embodiment of the pickup tube of this invention.
  • FIG. 9B is a sectional view of the pickup tube shown in FIG. 9A taken along a line IXB-IXB;
  • FIG. 10A shows a plan view of still another embodiment of the pickup tube of this invention.
  • FIGS. 10B and 10C are sectional views of the pickup tube shown in FIGS. 10A taken along lines XBXB and XCXC, respectively;
  • FIG. 11A shows a plan view of yet another embodiment of the pickup tube embodying the invention
  • FIGS. 11B and 11C are sectional views of the pickup tube shown in FIG. 11A taken along lines XIBXIB and XICXIC, respectively.
  • the construction of a filter encoded pickup tube will firstly be described with reference to FIG. 1 of the accompanying drawing.
  • the pickup tube 1 illustrated therein comprises an electron gun 2, a focusing coil 3,
  • the optical colour analyzing stripe filter 6 comprises a dichroic filter including an alternate lamination of the layers of titanium dioxide TiO and silicon dioxide SiO for example, and includes two filter components 6A and 68, as shown in FIG. 2.
  • One component 6A includes an alternate arrangement of stripe filter elements 6AW transmitting light of substantially all colours from an object, not shown, and stripe filter elements 6AR blocking the red light. Filter elements 6AW and 6AR have the same width DR.
  • the other stripe filter component 63 includes a similar alternate arrangement of stripe filter elements 6BW transmitting light of substantially all colours and stripe filter elements 688 blocking blue light. Again, stripe filter elements 6BW and 6B8 have the same width DB. Widths DR and DB should be different, and in FIG. 2, DB is shown narrower than DR.
  • stripe filter elements 6AR, 6AW and 6BB, 6BW,of two filter components 6A and 6B are shown parallel with each other, actually, however, these two groups of the stripe filter elements intersect each other at a certain angle as shown in FIG. 3 so as to decrease the beats caused by these two groups.
  • FIGS. 4 and 5 One example of the actual construction of the optical colour analyzing stripe filter 6 is shown in FIGS. 4 and 5. More particularly, only stripe filter elements 6AR of the filter element 6A which substantially block red light are formed on the glass window 5 (see FIG. 5b) and thereafter the stripe filter elements 688 of the other filter component 68 which substantially block the blue light are formed on the stripe filter elements 6AR without forming the stripe filter elements 6AW and 6BW of the filter components 6A and 63, respectively, which transmit the light of all colours, as shown in FIG. 5a. According to this invention, for the purpose of eliminating or alleviating the surface irregularity of the optical colour analyzing stripe filter as shown in FIGS.
  • false signal preventing films consisting of a glass layer or a SiO layer are applied as shown by 12 in FIG. 6a, and polished or etched to form a smooth surface 12a in FIG. 6b.
  • a similar film 13 applied as shown in FIG. 6c is polished or etched as shown at 13a in FIG. 6d.
  • the false sig nal preventing film 13 is applied thereon as shown in FIG. 6c and polished or etched as shown in FIG. 6d.
  • FIGS. 7b and 7c are repeatedly formed on the resulting assembly and finished products having substantially flat and smooth surfaces 14a, and 15 a as shown in FIGS. 7b and 7c are produced by polishing or chemically etching the surfaces, or the polishing and chemical etching in combination.
  • FIGS. 8 through 11 show different constructions of the false signal preventing films embodying the invention.
  • one or more types of the groups of the optical colour analyzing stripe filters are arranged in parallel or cross superposition relationship on one side surface of the transparent glass window 5 whose peripheral edge is vacuum sealed to the tube.
  • a circular area 16 where the optical colour analyzing stripe filter 6 is coated (hereinafter referred to as a filter coated area 16) is provided, which of course contains the effective image pickup region 29 of the rectangular configuration of the pickup tube, and a false signal preventing film 18 of a layer of transparent solid substance such as a glass layer or a SiO layer is applied in concentric with the filter coated area 16, an area 17 of the film 18 (hereinafter referred to as a film coated area 17) having larger diameter than the filter coated area 16. It was found that if the length of the extension I of the film coated area 17 beyond the filter coated area 16 is limited to be equal to or less than about 5 mm, the false signal preventing film 18 would never peel off and/or crack.
  • the peel ing off and/or cracking is encountered.
  • the bonding surface between the false signal preventing film 18 and the mirror surface of the transparent glass window 5 is limited to an annular surface having a maximum width of about 5 mm it is possible to prevent the peeling off and/or the cracking of the false signal preventing film, owing to the bonding force between the film and the irregular surface of the optical colour analyzing stripe filter.
  • FIGS. 9A and 9B show another example of the pickup tube embodying the invention.
  • the film coated area 17 is made smaller than the filter coated area 16 on which the optical colour anacoated area 17 is made to be equal to or a little larger than the effective image pickup region 19, thus leaving exposed the annular portion of the filter coated area 16 about the film 18. It was confirmed that this construction also effectively prevents peeling off and/or cracking of the false signal preventing film 18. Again, it is preferable to limit the width of the annular portion to be equal to or less than 5 mm.
  • FIGS. 8A and 88 an embodiment has been described wherein the film coated area l7 extends beyond the periphery of the filter coated area 16 and in FIGS. 9A and 98 another embodiment has been described wherein the film coated area 17 is contained within the filter coated area 16.
  • the film coated area 17 may be so formed as to irregularly intersect the periphery of the filter coated area 16.
  • the periphery of the film coated area 17 may be confined in a region defined by the outward extension of 5 mm from the periphery of the filter coated area 16 and the inward spacing of 5 mm from the periphery of the filter coated area 16, the region having the width equal to 10 mm.
  • FIGS. 10A, 10B and 10C illustrate still another embodiment of the novel pickup tube of this invention.
  • a peripheral coating layer made of a different or same material as the stripe filter 6 which is formed in a rectangular filter coated area 16 and of a material different from that of the false signal preventing film 18 is formedto surround the area 16.
  • the area of the peripheral coating layer 20 is hereinafter referred to a layer area 21.
  • the effective image pickup region 29 is also rectangular and contained in the area 16.
  • the peripheral coating layer 20 is formed independently of the optical colour analyzing stripe filter 6 to surround the same such that the film coated area 17 covers the filter lyzing stripe filter is formed.
  • the film coated area 16 and extends beyond the layer area 21 with an extension I.
  • the extension I is of a maximum width of less than about 5 mm.
  • FIGS. 11A, 11B and 11C show another embodiment of this invention, wherein the film coated area 17 covers filter coated area 16 and is contained within the layer area 21, leaving exposed an extension I of the same. In this case too, it is advantageous to limit the extension l to be less than about 5 mm.
  • FIGS. 10A, 10B and 10C still another embodiment has been described wherein the film coated area 17 extends beyond the periphery of the layer area 21 and in FIGS. 11A, 11B and 11C further embodiment has been described wherein the periphery of the film coated area 17 is contained within the layer area 21.
  • the film coated area 17 may be so formed as to irregularly intersect the periphery of the layer area 21.
  • the periphery of the film coated area 17 may be confined in a region defined by the outward extension of 5 mm from the periphery of the layer area 21 and the inward spacing of 5 mm from the periphery of the layer area 21, the region having the width equal to 10 mm.
  • the filter coated area 16 shows a region in which two types of the optical colour analyzing stripe filters are arranged in crossed and superposed relationship as shown in FIG. 4 or only one type of the optical colour analyzing stripe filter is arranged as shown in FIG. 5b, and only the effective pickup region 19, in this area 16, is used to prevent the generation of the false signals, so that the configuration of the area 16 is not necessarily be limited to circular or rectangular as illustrated in these figures. The same is true for the peripheral coating layer 20.
  • an optical colour analyzing stripe filter in the form of the interference filter coating is formed on a glass substrate, and the false signal preventing film 18 having a diameter larger or smaller by less than 5 mm than that of the filter is formed.
  • the film firstly formed on the glass substrate should not always be constituted by a dichroic filter but may be formed of a substance different from the false signal preventing film and that the filter film should not always be constituted by parallel stripes.
  • any other configurations of the filter such as a wire net or spots can also effectively prevent the peeling off and/or cracking of the false signal preventing film provided that the filter has a suitable percentage surface area, with respect to the area of false signal preventing film arrangement, configuration and dimension equivalent to those of 6AR and 6BB shown in FIG. 4.
  • the area in which the false signal preventing film is formed it is possible to prevent the peeling off and/or cracking of the film and hence the peeling off and/or cracking of the transparent conductive film caused by such peeling off and/or cracking of the false signal preventing film, as well as the decrease in the conductivity of the transparent conductive film.
  • a colour vidicon type pickup tube for use in single tube type or two tube type colour television camera systems comprising a transparent glass window, an optical colour analyzing stripe filter formed on the rear surface of said glass window, and a false signal preventing film made of a layer of transparent solid substance and formed on the surface of said filter, the improvement wherein said false signal preventing film is formed in such a manner that the periphery of said false signal preventing film is confined in a region defined by an outward extension of mm from the periphery of said optical colour analyzing stripe filter and an inward spacing of 5 mm from the periphery of the same, said outward extension not touching the vacuum sealed portion of said glass window.
  • a colour vidicon type pickup tube for use in single tube type or two tube type colour television camera systems comprising a transparent glass window, an optical colour analyzing stripe filter formed on the rear surface of said glass window, a false signal preventing film made of a layer of transparent solid substance and formed on the surface of said filter, and a peripheral coating layer formed to surround the periphery of said optical colour analyzing stripe filter, the improvement wherein said false signal preventing film is formed in such a manner that it covers said optical colour analyzing stripe filter and said peripheral coating layer and that the periphery of said false signal preventing film is confined in a region defined by an outward extension of 5 mm from the periphery of said peripheral coating layer and an inward spacing of 5 mm from the periphery of the same, said outward extension not touching the vacuum sealed portion of said glass window.
  • peripheral coating layer is made of a substance which is the same as that comprising at least a portion of said optical colour analyzing stripe filter.
  • peripheral coating layer is made of a material containing a substance from which at least a portion of said optical colour analyzing stripe filter is made of.
  • peripheral coating layer is made of a substance different from that of said false signal preventing film.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Color Television Image Signal Generators (AREA)
  • Optical Filters (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
US448460A 1973-04-11 1974-03-06 Colour pickup tube having a false signal preventing film Expired - Lifetime US3912962A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP48040456A JPS49129436A (enrdf_load_stackoverflow) 1973-04-11 1973-04-11

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US3912962A true US3912962A (en) 1975-10-14

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US448460A Expired - Lifetime US3912962A (en) 1973-04-11 1974-03-06 Colour pickup tube having a false signal preventing film

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US (1) US3912962A (enrdf_load_stackoverflow)
JP (1) JPS49129436A (enrdf_load_stackoverflow)
FR (1) FR2225837B1 (enrdf_load_stackoverflow)
GB (1) GB1456443A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3986069A (en) * 1974-04-24 1976-10-12 Tokyo Shibaura Electric Co., Ltd. Color stripe filter with two protective layers
US4029394A (en) * 1974-05-16 1977-06-14 Minolta Camera Kabushiki Kaisha Color encoding filter and method for making the same
US4107568A (en) * 1973-12-03 1978-08-15 Hitachi, Ltd. Face plate for color pick-up tube
US5730766A (en) * 1996-11-05 1998-03-24 Bha Group, Inc. Non-round unitary filter cartridge

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5942749B2 (ja) * 1979-07-11 1984-10-17 株式会社東芝 多層膜のエツチング方法

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3026416A (en) * 1957-07-23 1962-03-20 Rca Corp Photoconductive devices
US3772552A (en) * 1970-09-16 1973-11-13 Sony Corp Image pickup tube

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5531982B2 (enrdf_load_stackoverflow) * 1973-03-13 1980-08-22

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3026416A (en) * 1957-07-23 1962-03-20 Rca Corp Photoconductive devices
US3772552A (en) * 1970-09-16 1973-11-13 Sony Corp Image pickup tube

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4107568A (en) * 1973-12-03 1978-08-15 Hitachi, Ltd. Face plate for color pick-up tube
US3986069A (en) * 1974-04-24 1976-10-12 Tokyo Shibaura Electric Co., Ltd. Color stripe filter with two protective layers
US4029394A (en) * 1974-05-16 1977-06-14 Minolta Camera Kabushiki Kaisha Color encoding filter and method for making the same
US5730766A (en) * 1996-11-05 1998-03-24 Bha Group, Inc. Non-round unitary filter cartridge

Also Published As

Publication number Publication date
GB1456443A (en) 1976-11-24
DE2411583A1 (de) 1974-11-07
FR2225837B1 (enrdf_load_stackoverflow) 1976-10-08
JPS49129436A (enrdf_load_stackoverflow) 1974-12-11
DE2411583B2 (de) 1976-07-15
FR2225837A1 (enrdf_load_stackoverflow) 1974-11-08

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