US3866082A - Cathode ray tube for displaying coloured pictures - Google Patents

Cathode ray tube for displaying coloured pictures Download PDF

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Publication number
US3866082A
US3866082A US404356A US40435673A US3866082A US 3866082 A US3866082 A US 3866082A US 404356 A US404356 A US 404356A US 40435673 A US40435673 A US 40435673A US 3866082 A US3866082 A US 3866082A
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United States
Prior art keywords
strips
display screen
triplet
red
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
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US404356A
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English (en)
Inventor
Piet Gerard Joseph Barten
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US Philips Corp
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US Philips 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
    • H01J29/18—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

Definitions

  • Cent strips belonging to the Same triplet is at either [58] Fleld of Search" 313/69 70 92 92 side of the red strip at least 5% larger than the dis- 313/85 s tance between the centers of two adjacent strips of which one belongs to the triplet and the other belongs [5 6] References cue! to an adjacent triplet.
  • the invention relates to a cathode ray tube for displaying coloured pictures
  • a cathode ray tube for displaying coloured pictures
  • a.display screen having a large number of discrete regions which, upon bombardment with electrons, luminesce in three different colours
  • a colour selection mask having a large number of apertures, and means to produce three electrons beams converging towards the display secreen, each luminescent region being present in a path of an electron beam through one of the said apertures, said luminescent regions being arranged according to substantially parallel colour strips, said colour strip being arranged in triplets each containing three colour strips which luminesce green, red, and blue, respectively.
  • Such a cathode ray tube is known and is usually referred to as a shadow mask tube.
  • a tube of the type described in the preamble does not comprise, as the shadow mask tube generally used at the moment, a display screen having a hexagonal pattern ofluminescent dots, but comprises a display screen having luminescent strips which during normal operation are vertical. that is to say at right angles to the lines of a television screen.
  • the advantage of such a display screen having luminescent strips is that deviations from the correct place where an electron beam is to impinge upon the display screen (so-called landing errors) which are parallel to the direction of the strips, do not result in colour defects because the electron beam remains impinging upon the strip of the same colour.
  • the colour strips may be formed by continuous strips of one colour or by a series of elongate regions of one colour together constituting a strip.
  • the apertures in the colour selection mask can be formed in the same manner by long slots or by a seriesof elongate apertures together constituting a slot having reinforcement bridges.
  • a cathode ray tube of the type described in the preamble is characterized in that the central colour strip of each triplet luminesces red and that, over at least part of the display screen, the distance between the centers of two adjacent colour strips belonging to the same triplet is at least 5% larger than the distance between the centers of two adjacent colour strips of which one belongs to the said triplet and the other belongs to an adjacent triplet.
  • the decrease of the colour defects as a result oflanding errors of the electron beams as indicated by the invention is based on experiments which have demonstrated that the discoloration which occurs by landing of the red electron beam (by which is briefly meant the beam which transports the red picture signal) on the green or the blue colour strips is experienced to be more serious than landing of the green electron beam on the blue colour strips or landing of the blue electron beam on the green colour strips, while the latter is again experienced to be more serious than landing of the blue or the green electron beamon the red colour strips.
  • Green, red and blue is to be understood to mean herein the set of primary colours which is used in the conventional television systems to realise an optimum colour display.
  • a cathode ray tube according to the invention is characterised in particular in that the said percentage increases from 0% in the center of the display screen to a maximum of 20% at the edge of the display screen.
  • a cathode ray tube according to the invention may furthermore be provided with a light-absorbing layer between the individual colour strips to reduce the quantity of ambient light reflected by the display screen.
  • FIG. 1 is a cathode ray tube according to the invention
  • FIG. 2 shows a part of FIG. I on an enlarged scale
  • FIGS. 3 and 5 show two possibilities for the landing of the electron beams without using the invention
  • FIGS. 4 and 6 show two possibilities for the landing of the electron beams in a tube according to the invention and as compared with FIGS. 3 and 5, respectively.
  • FIG. I shows a colour television display tube having an evacuated envelope 1 comprising an electron gun 2, a colour selection mask 3, a display screen 4 and having deflection coils 5.
  • the electron gun 2 produces three electron beams 6, 7 and 8 which converge towards the display screen 4.
  • the axes of the electron beams 6, 7 and 8 in the non-deflected condition lie in the plane of the drawing.
  • the deflection coils 5 deflect the electron beams 6, 7 and 8 in such manner that the display screen 4 is scanned. Scanning occurs in known manner according to a line frame the lines of which are parallel to the plane of the drawing.
  • FIG. 2 illustrates the colour selection by means of the colour selection mask 3 and shows the encircled part of FIG. 1 on a larger scale.
  • the colour selection mask 3 has a number of apertures 9 which pass the electron beams 6, 7 and 8 partly.
  • the electron beam 6 only impinges upon phosphor strips of the display screen 4 which are denoted by G and which luminesce green.
  • the beam 7 only impinges upon red (R) phosphor strips and the beam 8 only upon blue (B) phosphor strips.
  • the display screen 4 furthermore comprises in known manner a very thin aluminium layer which is permeable to electrons.
  • Three phosphor strips belonging to one aperture of the colour selection mask 3 constitute a triplet.
  • the phosphor strips are substantiallyparallel and extend at right angles to the lines of the already mentioned line frame.
  • the apertures 9 are slot-shaped and are of course parallel to the phosphor dots.
  • a slot-shaped aperture is also to be understood to mean a row of apertures parallel to the phosphor strips which together constitute a slot having reinforcement bridges.
  • said reinforcement bridges may be recognizable in the phosphor strips.
  • the tube is manufactured by providing a photosensitive layer .on a part of the window of the tube and exposing said layer to the light of a source the place of which is related to the deflection point of the electron beams in the deflection coils 5.
  • Exposure and development of the photosensitive layer occur in known manner according to a photochemical or an electrophotographical method.
  • a wider triplet means that the distance between the phosphor strips of the triplet becomes larger but the distance to adjacent triplets becomes smaller. Since, as already stated, red is most sensitive for landing errors, the colour defects are decreased by choosing red for the central phosphor strip of a triplet.
  • the invention can be carried out in various manners. Two possibilities are explained by means of the FIGS. 4 and 6 and compared with the known possibilities as shown in FIGS. 3 and 5.
  • the phosphor strips are shaded and furthermore denoted by G for green, R for red and B for blue.
  • the central three strips in each figure form a triplet.
  • the extreme left and the extreme right strip are of adjacent triplets.
  • the spots of the electron beams are shown diagrammatically by rounded rectangles.
  • the distance between the triplets of phosphor strips in FIG. 3 to FIG. 6 is 0.700 mm measured between the centers of two red phosphor strips.
  • FIG. 3 shows a configuration in which the invention is not used.
  • the display screen is entirely filled with phosphor.
  • the phosphor strips G, R and B are equally wide, namely each 0.233 mm.
  • the electron spots impinge upon the center of the phosphor strips.
  • the landing freedom is equally large for all three electron beams.
  • FIG. 4 shows a configuration which is obtained by applying the invention to the configuration of FIG. 3.
  • the red phosphor strip R is 0.300 mm wide.
  • the green phosphor strip G and the blue phosphor strip B are each 0.200 mm wide.
  • the distance between the centers of G and B is equal to 0.200 mm and between the centers of G and R and R and B, re spectively, it is equal to 0.250 mm.
  • the electron spots are equidistant.
  • Comparison of FIG. 4 to FIG. 3 proves that the landing freedom of the red beam is increased.
  • the landing freedom of the blue beam relative to the green phosphor strip and of the green beam relative to the blue phosphor strip has remained the same.
  • the landing freedom of the green and the blue beams relative to the red phosphor strip is reduced but provides the least observable colour defects.
  • Said colour defects can be reduced by making the red phosphor strip R narrower while maintaining the stated distances between the centres of G, R and B and while maintaining equidistant electron spots.
  • a space which is not covered with phosphor is then obtained between R and G and B and R, respectively, as a result of which a small landing error of the green or the blue beam causes same to miss the corresponding phosphor strip partly but not yet to impinge upon the red phosphor strip R.
  • FIG. 5 shows a configuration in which the invention is not used.
  • the phosphor screen is not filled entirely with phosphor.
  • the electron spots overlap the phosphor strips.
  • Such a configuration with so-called negative tolerance is very suitable to fill the space between the phosphor strips with a lightabsorbing layer so as to restrict the detrimental reflection of ambient light by the display screen.
  • the phosphor strips G, R and B are each 0.080 mm wide.
  • the distances between the phosphor strips are 0.233 mm.
  • the center of the electron spots coincides with the center of the phosphor strips.
  • the landing freedom is equally large for the three electron beams.
  • FIG. 6 shows a configuration which is obtained by applying the invention to the configuration of FIG. 5.
  • the phosphor strips G, R and B are also 0.080 mm wide.
  • the distance between the centers of B and G is 0.180 mm and between the centers of G and R and R and B, respectively, equal to 0.260 mm.
  • the electron spots are not equidistant.
  • the distance between the electron spots of the green and blue beams is larger than between that of the green and the red and the red and the blue beams, respectively.
  • Comparison of FIG. 6 with FIG. 5 proves that the landing freedom of the red beam is increased.
  • the landing freedom of the blue beam relative to the green phosphor strips and of the green beam relative to the blue phosphor strips has remained the same.
  • the landing freedom of the green and the blue beams relative to the red phosphor strip is slightly decreased but this'provides the least observable colour defects.
  • a cathode ray tube for displaying color pictures comprising a display screen having a plurality of discrete regions which, upon bombardment with electrons, luminesce in three different colours, a color se lection mask having a plurality of apertures, and means to produce three electron beams converging towards the display screen, each luminescent region being present in a path of an electron beam through one of said apertures, said luminescent regions being arranged according to substantially parallel color strips, said color let and the other belongs to an adjacent triplet.
  • a cathode ray tube as claimed in claim 1 characterized in that the said percentage increases from 0% in the center of the display screen to a maximum of 20% at the edge of the display screen.
  • a cathode ray tube as claimed in claim 1 characterized in that the display screen comprises a lightabsorbing layer between the individual color strips.

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  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
US404356A 1972-10-17 1973-10-09 Cathode ray tube for displaying coloured pictures Expired - Lifetime US3866082A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7214003A NL7214003A (enrdf_load_stackoverflow) 1972-10-17 1972-10-17

Publications (1)

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US3866082A true US3866082A (en) 1975-02-11

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US404356A Expired - Lifetime US3866082A (en) 1972-10-17 1973-10-09 Cathode ray tube for displaying coloured pictures

Country Status (11)

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US (1) US3866082A (enrdf_load_stackoverflow)
JP (1) JPS4976464A (enrdf_load_stackoverflow)
AU (1) AU474034B2 (enrdf_load_stackoverflow)
BE (1) BE806161A (enrdf_load_stackoverflow)
CA (1) CA979476A (enrdf_load_stackoverflow)
DE (1) DE2348543A1 (enrdf_load_stackoverflow)
ES (1) ES419650A1 (enrdf_load_stackoverflow)
FR (1) FR2203165B1 (enrdf_load_stackoverflow)
GB (1) GB1420793A (enrdf_load_stackoverflow)
IT (1) IT996820B (enrdf_load_stackoverflow)
NL (1) NL7214003A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4193015A (en) * 1977-09-01 1980-03-11 U.S. Philips Corporation Color television display tube
US5122708A (en) * 1990-12-12 1992-06-16 North American Philips Corporation Color reference CRT and method of making

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6164045A (ja) * 1984-09-04 1986-04-02 Sony Corp ビ−ムインデツクス型カラ−陰極線管
DE4326586A1 (de) * 1993-08-07 1995-02-09 Nokia Deutschland Gmbh In-Line-Strahlerzeugersystem

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2741724A (en) * 1951-11-27 1956-04-10 Rauland Corp Image-reproducing device
US2802964A (en) * 1953-07-10 1957-08-13 Marconi Wireless Telegraph Co Color television systems
US3652895A (en) * 1969-05-23 1972-03-28 Tokyo Shibaura Electric Co Shadow-mask having graduated rectangular apertures
US3666462A (en) * 1969-03-28 1972-05-30 Zenith Radio Corp Process of screening a shadow mask color tube
US3790839A (en) * 1972-04-04 1974-02-05 Zenith Radio Corp Rectangular grade black surround screen

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2741724A (en) * 1951-11-27 1956-04-10 Rauland Corp Image-reproducing device
US2802964A (en) * 1953-07-10 1957-08-13 Marconi Wireless Telegraph Co Color television systems
US3666462A (en) * 1969-03-28 1972-05-30 Zenith Radio Corp Process of screening a shadow mask color tube
US3652895A (en) * 1969-05-23 1972-03-28 Tokyo Shibaura Electric Co Shadow-mask having graduated rectangular apertures
US3790839A (en) * 1972-04-04 1974-02-05 Zenith Radio Corp Rectangular grade black surround screen

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4193015A (en) * 1977-09-01 1980-03-11 U.S. Philips Corporation Color television display tube
US5122708A (en) * 1990-12-12 1992-06-16 North American Philips Corporation Color reference CRT and method of making

Also Published As

Publication number Publication date
ES419650A1 (es) 1976-03-16
GB1420793A (en) 1976-01-14
CA979476A (en) 1975-12-09
JPS4976464A (enrdf_load_stackoverflow) 1974-07-23
AU6132173A (en) 1975-04-17
AU474034B2 (en) 1976-07-08
NL7214003A (enrdf_load_stackoverflow) 1974-04-19
IT996820B (it) 1975-12-10
DE2348543A1 (de) 1974-04-25
FR2203165A1 (enrdf_load_stackoverflow) 1974-05-10
FR2203165B1 (enrdf_load_stackoverflow) 1976-10-01
BE806161A (fr) 1974-04-16

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