US3767954A - Cathode-ray tube having indexing strips on the screen for determining the position of the electron beam - Google Patents

Cathode-ray tube having indexing strips on the screen for determining the position of the electron beam Download PDF

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Publication number
US3767954A
US3767954A US00206285A US3767954DA US3767954A US 3767954 A US3767954 A US 3767954A US 00206285 A US00206285 A US 00206285A US 3767954D A US3767954D A US 3767954DA US 3767954 A US3767954 A US 3767954A
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US
United States
Prior art keywords
strips
screen
indexing
electron beam
ray tube
Prior art date
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
Application number
US00206285A
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English (en)
Inventor
Den Avoort P Van
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
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US Philips Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
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Publication of US3767954A publication Critical patent/US3767954A/en
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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
    • H01J29/18—Luminescent screens
    • H01J29/30—Luminescent screens with luminescent material discontinuously arranged, e.g. in dots, in lines
    • H01J29/32—Luminescent screens with luminescent material discontinuously arranged, e.g. in dots, in lines with adjacent dots or lines of different luminescent material, e.g. for colour television
    • H01J29/325—Luminescent screens with luminescent material discontinuously arranged, e.g. in dots, in lines with adjacent dots or lines of different luminescent material, e.g. for colour television with adjacent lines
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
    • G03C5/16—X-ray, infrared, or ultraviolet ray processes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N9/00—Details of colour television systems
    • H04N9/12—Picture reproducers
    • H04N9/16—Picture reproducers using cathode ray tubes
    • H04N9/22—Picture reproducers using cathode ray tubes using the same beam for more than one primary colour information
    • H04N9/24—Picture reproducers using cathode ray tubes using the same beam for more than one primary colour information using means, integral with, or external to, the tube, for producing signal indicating instantaneous beam position
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2231/00—Cathode ray tubes or electron beam tubes
    • H01J2231/12—CRTs having luminescent screens
    • H01J2231/121—Means for indicating the position of the beam, e.g. beam indexing

Definitions

  • the invention relates to a cathode-ray tube comprising a fluorescent screen having indexing strips for determining the position of an electron beam by means of radiation emitted by the indexing strips under the influence of the electron beam.
  • Such a cathode-ray tube is used, for example, for colour television.
  • the screen is then scanned by the electron beam under the influence of deflection means according to a frame of parallel lines.
  • the fluorescent screen comprises a pattern of phosphor strips normal to the scanning lines and separated by inactive strips,
  • the phosphor strips each luminescing under the influence of the electron beam in one of three primary colours.
  • a very thin conductive layer is present on the phosphor strips which passes the electron beam and reflects light of the phosphor strips in the direction of the viewer of the television picture.
  • On this conductive layer located at the inside of the cathode ray tube a layer with indexing strips is present.
  • Each indexing strip is preferably present opposite to an inactive strip.
  • the indexing strips are provided, for example, after every other inactive strip.
  • the indexing strips comprise a phosphor which preferably luminesces in a part of the spectrum which can easily be separated-from the .part of the spectrum of the said three primary colours, preferably in the ultraviolet range.
  • the signal supplied by the pick-up element is handled electronically and used for determining the position of the electron beam. In this manner the current intensity of the electron beam when it passes a given phosphor strip can be controlled with the 7 colour signal of the associated colour and a colour television picture is obtained.
  • the pick-up element is generally present outside the cathode-ray tube and receives the indexing signal via a light-pervious part of the wall of the cone of the tube. It is obvious that, with a larger maximum deflection angle upon scanning the screen, larger differences will occur in the space angle at which the photo cathode of the pick-up element is seen from various points of the screen. This results in great differences in the quantity of light of the indexing strips received by the pick-up element if, as is usual, said strips have substantially the same width everywhere. This effect occurs in particular with short cathode-ray tubes having large screens and hence large deflection angles and it is just this type of tube that is most desirable for practical reasons.
  • the signal-to-noise ratio of the indexing signaloriginating from the edges of the screen is smaller than the signal-to-noise ratio of the indexing signal originating from the center of the screen.
  • the load of the photocathode of the pick-up element increases according as the indexing signal originating from the centre of the screen is larger and this must be chosen to be large to receive still sufficient signal from the edge.
  • the electronic circuit which handles the indexing signal must be capable of handling a large amplitude range without introducing phase shift.
  • the indexing signal received by the photo-cathode of the pick-up element has much smaller variations in amplitude as a function of the place on the screen than in the case without application of the invention.
  • the imaginary point should then lie in the proximity of the point of intersection of the axis of the photomultiplier with the fluorescent screen and will generally be situated in the proximity of the centre of the screen. Very small variations of the indexing signal are obtained for practical tubes if the ratio of the maximum and the minimum width of the indexing strip is at least about 1.5.
  • a cathode-ray tube comprising a screen having phosphor strips luminescing'in different colours
  • the phosphor strips are preferably wider in the proximity of the imaginary point than at the edge of the screen.
  • the inactive (nonluminescing) strips may also be narrow and more space is available for the phosphor strips.
  • a better adaptation of the width of the phosphor strips to the width of the electron beam throughout the screen is possible.
  • FIG. 1 shows acathode-ray tube according to the invention which is provided with a pick-up element and FIG. 2 shows .a part of the screen of said tube on an enlarged scale.
  • the cathode-ray tube shown in FIG. 1 comprises in an envelope '1 an electron gun 2 for producing an electron beam 3 which is deflected under the influence of deflection coils 4 over the fluorescent screen 5 on the window 6 of the tube.
  • a pick-up element 7 Secured to the tube is a pick-up element 7 having a photo-cathode 8 and an electron multiplier 9.
  • the point of intersection of the axis of the pick-up element 7 with the screen '5 lies in the proximity of the centre of the screen '5.
  • the stream of photo electrons emitted by the :photo cathode .8 is amplified in the electron multiplier-9 and constitutes an amplified indexing signal for phosphor strips '12, 14, 16, 18, 20 and 22 which luminesce in red, blue, .green, red, blue and green, respectively, under the influence of an electron beam.
  • lnactive strips ll, l3, l5, l7, l9 and 21 are present hetween the phosphor strips.
  • On the layer of phosphor strips and inactive strips a thin layer 26 is present which passes electrons and reflects light of the phosphor strips in the direction of the window 6.
  • Indexing strips 23, 24 and 25 on the layer 26 emit light to the pick-up element 7 (FIG. 1) in the direction of the arrow 10 (FIG. 1) under the influence of the electron beam.
  • a screen which is, for example, 52 cm wide, comprises approximately 420 triplets having a rod, a blue and a green phosphor strip separated by inactive strips. Opposite to every other inactive strip is an indexing strip.
  • the width of the central indexing strips in the centre of the screen is approximately 0.1 mm and at the edge of the screen it is approximately 0.15 mm.
  • the width of the indexing strips at the edge of the screen is approximately 0.15 mm in the centre of the strip and approximately 0.2 mm at the ends.
  • the respective widths of the indexing strips regularly increase between the places on the screen from the centre of the screen towards the edge.
  • An improved cathode ray tube apparatus comprismg:
  • a fluorescent screen located within said envelope at said window portion and comprising a plurality of phosphor strips characterized in that various ones of said strips luminesce in different colors in response to electron impingement, said screen further comprising an electron permeable light refleeting layer disposed over the side of said phosphor strips remote from said window, and a number of discrete indexing strips disposed on said light reflecting layer and emitting radiation in response to electron impingement thereon;
  • means for indexing said electron beam on said screen comprising a pick-up element responsive to and arranged to receive radiation emitted from said indexing strips, the axis of said pick-up element intersecting said screen at an imaginary point,
  • said indexing strips having individual widths increasing with increasing distance from said imaginary point in the direction toward the edge of said screen, the axes of said phosphor strips and said indexing strips being transverse to the scanning direction of said electron beam.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
US00206285A 1970-12-29 1971-12-09 Cathode-ray tube having indexing strips on the screen for determining the position of the electron beam Expired - Lifetime US3767954A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7018913A NL7018913A (OSRAM) 1970-12-29 1970-12-29

Publications (1)

Publication Number Publication Date
US3767954A true US3767954A (en) 1973-10-23

Family

ID=19811908

Family Applications (1)

Application Number Title Priority Date Filing Date
US00206285A Expired - Lifetime US3767954A (en) 1970-12-29 1971-12-09 Cathode-ray tube having indexing strips on the screen for determining the position of the electron beam

Country Status (7)

Country Link
US (1) US3767954A (OSRAM)
BE (1) BE777414A (OSRAM)
CA (1) CA937973A (OSRAM)
DE (1) DE2159700A1 (OSRAM)
FR (1) FR2131305A5 (OSRAM)
GB (1) GB1331550A (OSRAM)
NL (1) NL7018913A (OSRAM)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4194140A (en) * 1977-03-28 1980-03-18 Tokyo Shibaura Electric Co., Ltd. Beam-indexing color image-presentation cathode ray tube
EP0049515A3 (en) * 1980-10-07 1982-09-22 Sanyo Electric Co., Ltd. Beam-indexing color picture tube
US4459512A (en) * 1980-09-22 1984-07-10 Yokogaw Hokushin Electric Corp. Cathode-ray display tube for color printers
US4757231A (en) * 1985-09-12 1988-07-12 Sony Corporation Beam-index type color cathode ray tube device
EP0285224A3 (en) * 1987-04-03 1991-03-06 Koninklijke Philips Electronics N.V. Colour cathode ray tube
WO2003021628A1 (en) * 2001-09-06 2003-03-13 Koninklijke Philips Electronics N.V. Tracking tube with adapted tracking structure

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2774908A (en) * 1955-03-30 1956-12-18 Rca Corp Cathode-ray tubes of the feed-back variety
US2790107A (en) * 1955-04-04 1957-04-23 Philco Corp Indexing strip structure for cathode ray tubes
US3248218A (en) * 1961-06-09 1966-04-26 Rca Corp Variable density layers of particles and method of preparing them

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2774908A (en) * 1955-03-30 1956-12-18 Rca Corp Cathode-ray tubes of the feed-back variety
US2790107A (en) * 1955-04-04 1957-04-23 Philco Corp Indexing strip structure for cathode ray tubes
US3248218A (en) * 1961-06-09 1966-04-26 Rca Corp Variable density layers of particles and method of preparing them

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4194140A (en) * 1977-03-28 1980-03-18 Tokyo Shibaura Electric Co., Ltd. Beam-indexing color image-presentation cathode ray tube
US4459512A (en) * 1980-09-22 1984-07-10 Yokogaw Hokushin Electric Corp. Cathode-ray display tube for color printers
EP0049515A3 (en) * 1980-10-07 1982-09-22 Sanyo Electric Co., Ltd. Beam-indexing color picture tube
US4757231A (en) * 1985-09-12 1988-07-12 Sony Corporation Beam-index type color cathode ray tube device
EP0285224A3 (en) * 1987-04-03 1991-03-06 Koninklijke Philips Electronics N.V. Colour cathode ray tube
WO2003021628A1 (en) * 2001-09-06 2003-03-13 Koninklijke Philips Electronics N.V. Tracking tube with adapted tracking structure
US20030057896A1 (en) * 2001-09-06 2003-03-27 Bergman Anthonie Hendrik Tracking tube with adapted tracking structure

Also Published As

Publication number Publication date
FR2131305A5 (OSRAM) 1972-11-10
DE2159700A1 (de) 1972-07-27
BE777414A (fr) 1972-06-28
GB1331550A (en) 1973-09-26
NL7018913A (OSRAM) 1972-07-03
CA937973A (en) 1973-12-04

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