US3742291A - Colour display tubes - Google Patents

Colour display tubes Download PDF

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Publication number
US3742291A
US3742291A US00168682A US3742291DA US3742291A US 3742291 A US3742291 A US 3742291A US 00168682 A US00168682 A US 00168682A US 3742291D A US3742291D A US 3742291DA US 3742291 A US3742291 A US 3742291A
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US
United States
Prior art keywords
phosphor
spectral peaks
colour
colour display
display 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
US00168682A
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English (en)
Inventor
I Yamada
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.)
Electronics Corp of America
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Electronics Corp of America
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
Priority claimed from JP6789670A external-priority patent/JPS4919935B1/ja
Priority claimed from JP6789770A external-priority patent/JPS4919936B1/ja
Application filed by Electronics Corp of America filed Critical Electronics Corp of America
Application granted granted Critical
Publication of US3742291A publication Critical patent/US3742291A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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
    • H01J29/187—Luminescent screens screens with more than one luminescent material (as mixtures for the treatment of the screens)
    • 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
    • H01J29/20—Luminescent screens characterised by the luminescent material

Definitions

  • 29/52 cent screen is caused to luminesce by irradiating it with Field Search 313/92 42 P; an electron beam, the flourescent screen is coated with 315/30 at least one phosphor having at least two discrete spectral peaks of different excitation and photo-persistence Reierellces cited characteristics and there is provided means for varying UNITED STATES PATENTS the interval during which the electron beam is permit- 3 502937 3/1970 Bader et a].
  • 315/ x impinge the wheeby 3,575,627 4/1971 Nicoll 313/92 PH cause it luminesce at the Selected one of the Spectral 3,454,715 7/1969 Larach er al. 313 92 PH x P 6 Claims, 9 Drawing Figures LLI CID
  • each one of these prior colour cathode ray tubes is difficult to manufacture owing to its compli- ,cated operating circuit and it was difficult to provide colour cathode ray tubes of desired characteristics.
  • a shadow mask type colour cathode ray tube as an example, as shown in FIG. I, it utilizes three electron guns 1 of red (R), green (G) and blue (B) colours and after being accelerated and focused, three electron beams emanated from these guns, are caused to impinge upon phosphor dots of R, G and B on the face plate 3 through a shadow mask 2 thus causing the dots to luminesce.
  • Such a shadow mask type colour cathode ray tube requires use of three electron guns as well as the shadow mask thus complicating the construction.
  • Colour Netron and chromatron type colour cathode ray tubes it is necessary to use colour switching grids.
  • a more specific object of this invention is to provide an improved colour display tube in which it is not necessary to use three electron guns, a shadow mask of expensive construction and trios of phosphor dots formed on the fluorescent screen as well as colour swithing grids.
  • a colour display tube comprising a source of electron beam, a fluorescent screen coated with at least one phosphor having at least two discrete spectral peaks of different excitation and photopersistency characteristics and means for varying the interval during which the electron beam is permitted to impinge upon the fluorescent screen whereby to cause it to luminesce at the selected one of the spectral peaks.
  • the phosphor is required to have at least two discrete spectral peaks at different wavelengths, whereas when a mixture of phosphors are used such phorphors should have spectral peaks at different wavelengths.
  • the spectral peaks have different excitation and photopersistancy characteristics, and according to this invention it is possible to cause the display tube to selectively operate at the selected one of the spectral peaks by merely varying the width of the pulse voltage applied upon the control grid.
  • FIG. 1 shows a diagrammatic sectional view of a prior art shadow mask type colour cathode ray tube
  • FIG. 2 shows a luminescence characteristic of a phorphor having two spectral peaks at different colours
  • FIG. 3 is a plot showing the excitation and photopersistency characteristics at two spectral peaks shown in FIG. 2
  • FIG. 4 is a connection diagram to explain the driving system of a colour display tube having a fluorescent screen coated with a phosphor having two speral peaks;
  • FIGS. 5a and 5b show waveforms illustrating the luminescence at two spectral peaks upon application of a pulse voltage of small width
  • FIGS. 6a and 6b show waveforms illustrating the luminescence at two spectral peaks upon application of a pulse voltage of large width
  • FIG. 7 shows luminescence characteristics of two phosphors having discrete spectral peaks.
  • peak A lies near the wavelength of red whereas peak B near the wavelength of blue.
  • the luminescence used in the present invention is, for example, ZnS Cu Mn Cl or ZnS Cu Mn Ki.
  • the build-up characteristic of the luminescence near peak A is very slow, so that the luminescence does not reach the steady state immediate after excitation
  • peak B the buildup is fast and the photopersistency is also short compared to peak A. Further, it is assumed that the intensity of luminescence is lower at peak B than at peak A.
  • FIG. 3 shows the excitation and the photopersistence charactersistics at these two spectral peaks of different colours in which tB represents the excitation time required for the peak B to reach the steady state which builds-up fast whereas tA the excitation time required for the peak A to reach the steady state which builds-up slowly.
  • the colour display tube embodying the invention comprises a fluorescent screen coated with a phosphor having two spectral peaks of different colours.
  • FIG. 4 shows a driving circuit of a colour display tube having such a fluorescent screen.
  • the display tube employs a single electron gun of the conventional construction.
  • the colour display tube shown in FIG. 4 comprises a fluorescent screen 11, a cathode electrode 12, and first and second electrodes 13 and 14.
  • a pulse voltage is impressed upon the first grid 13 with one terminal of the cathode electrode 12 grounded. Then an electron beam corresponding to the pulse voltage will be emitted from the electron gun to reach the fluorescent screen 11.
  • a pulse voltage of small width shown in FIG. 5a is applied to the first gride 13 thus causing the electron beam to impinge upon the fluorescent screen.
  • the luminescence exhibits essentially the colour at the peak B and the colour at the peak A of slow build-up does not appear.
  • a pulse voltage of a large width as shown in FIG. 6a is impressed. Then, by irradrating the fluorescent screen with the electron beam the peak B luminesces at once with its inherent colour. Peak A is also excited sufficiently to luminesce and, as shown in FIG. 6b, increases in intensity as the large width pulses are applied because of its long photo-persistency. If it is designed to cause the intensity of the luminescence at peak B to be larger than that at peak A, a mixed colour corresponding to peaks A and B will be resulted. In this manner, the fluorescent screen coated with a phosphor having two or more spectral peaks can produce variable colours by varying the width of the applied pulse.
  • the invention is applied to a colour cathode ray tube it is to be understood that the invention can also be applied to another type of colour display tube such as a colour fluorescent character display tubes wherein colour patterns are displayed by irradiating a fluorescent screen with an electron beam.
  • the purpose of the invention can also be accomplished by using two types of phosphors having different spectral peaks thus emanating different colours. More, particularly, the phosphor utilized in the first embodiment can be substituted by a mixture of a first phorphor having a spectral peak A near the wavelength of red and a second phosphor having a spectral peak B near the wavelength of blue, as shown in FIG. 7.
  • the first phosphor may comprise Zn,,(PO Mn, MgF, Mn or Mg SiO; M whereas the second phosphor may comrpise (Ca, Mg), SiO Ce, ZnS Ag or ZnO Zn.
  • the peak A shown in FIG. 7 has a relatively slow build-up and relatively long decay or photo-persistency
  • peak B has a relatively fast buid-up and short photo-persistency.
  • the second phosphor has a quick response to the electron beam.
  • the excitation characteristics and the photo-persistency characteristics of the first and second phosphors can also be shown by FIG. 3.
  • the half-period of Zn(IO.,) Mn (the first phosphor) equals 10 n whereas that of (CaMg) SiO Ce (the second phosphor) equals 0.03p.
  • it wll be clear that the same result can also be accomplished by varying the ratio of admixture of the two phosphors. It is also possible to admix three of more phosphors having different spectral peaks or emanating different colours.
  • the invention provides a colour display tube capable of emanating different colours by merely coating a phosphor having a plurality of spectral peaks or a mixture of phosphors having different peaks upon a fluorescent screen.
  • a colour display tube capable of emanating different colours by merely coating a phosphor having a plurality of spectral peaks or a mixture of phosphors having different peaks upon a fluorescent screen.
  • a colour display tube comprising a source of electron beam, a fluorescent screen coated with at least one phosphor having at least two discrete spectral peaks of different excitation time and photo-persistency characteristics and means for varying the intervals during which'said electron beam is permitted to impinge upon said fluorescent screen whereby 'to cause it to luminesce at the selected one of said spectral peaks.
  • one of said phosphor comprises a member selected from the group consisting of Zn (PO Mn, MgF Mn and MgSiO Mn and the other phosphor comprises a member selected from the group consisting of (Ca.Mg) SiO Ce, ZnS Ag and ZnO Zn.

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  • Luminescent Compositions (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
US00168682A 1970-08-04 1971-08-03 Colour display tubes Expired - Lifetime US3742291A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP6789670A JPS4919935B1 (enrdf_load_stackoverflow) 1970-08-04 1970-08-04
JP6789770A JPS4919936B1 (enrdf_load_stackoverflow) 1970-08-04 1970-08-04

Publications (1)

Publication Number Publication Date
US3742291A true US3742291A (en) 1973-06-26

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Application Number Title Priority Date Filing Date
US00168682A Expired - Lifetime US3742291A (en) 1970-08-04 1971-08-03 Colour display tubes

Country Status (4)

Country Link
US (1) US3742291A (enrdf_load_stackoverflow)
CA (1) CA935500A (enrdf_load_stackoverflow)
FR (1) FR2103954A5 (enrdf_load_stackoverflow)
GB (1) GB1330235A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4301388A (en) * 1977-06-02 1981-11-17 Tektronix, Inc. Color coding of write-through information in direct viewing bistable storage CRT display
US4424467A (en) 1979-07-04 1984-01-03 Matsushita Electronics Corporation Cathode-ray tube having a mixture of long and short persistence phosphors
US4689520A (en) * 1983-10-31 1987-08-25 Sony Corporation Color cathode ray tube having an improved color phosphor screen

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4301388A (en) * 1977-06-02 1981-11-17 Tektronix, Inc. Color coding of write-through information in direct viewing bistable storage CRT display
US4424467A (en) 1979-07-04 1984-01-03 Matsushita Electronics Corporation Cathode-ray tube having a mixture of long and short persistence phosphors
US4689520A (en) * 1983-10-31 1987-08-25 Sony Corporation Color cathode ray tube having an improved color phosphor screen

Also Published As

Publication number Publication date
GB1330235A (en) 1973-09-12
CA935500A (en) 1973-10-16
DE2138846B2 (de) 1975-05-22
DE2138846A1 (de) 1972-02-10
FR2103954A5 (enrdf_load_stackoverflow) 1972-04-14

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