CA1086810A - Color cathode ray tube having a striped phosphor screen - Google Patents
Color cathode ray tube having a striped phosphor screenInfo
- Publication number
- CA1086810A CA1086810A CA179,953A CA179953A CA1086810A CA 1086810 A CA1086810 A CA 1086810A CA 179953 A CA179953 A CA 179953A CA 1086810 A CA1086810 A CA 1086810A
- Authority
- CA
- Canada
- Prior art keywords
- screen
- mask
- apertures
- ray tube
- cathode ray
- 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
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Classifications
-
- 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
-
- 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
- H01J29/06—Screens for shielding; Masks interposed in the electron stream
- H01J29/07—Shadow masks for colour television tubes
- H01J29/076—Shadow masks for colour television tubes characterised by the shape or distribution of beam-passing apertures
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
- H01J9/22—Applying luminescent coatings
- H01J9/227—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines
- H01J9/2271—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines by photographic processes
- H01J9/2272—Devices for carrying out the processes, e.g. light houses
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
- H01J9/22—Applying luminescent coatings
- H01J9/227—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines
- H01J9/2278—Application of light absorbing material, e.g. between the luminescent areas
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Electrodes For Cathode-Ray Tubes (AREA)
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
Abstract
A COLOR CATHODE RAY TUBE HAVING
A STRIPED PHOSPHOR SCREEN
ABSTRACT OF THE DISCLOSURE
This invention provides a color cathode ray tube which includes a curved screen provided with elemental phosphor stripes substantially vertically oriented, and running cyclically red, green and blue. Spaced inwardly from the screen is a shadow mask containing small rectangular apertures, and the cathode ray tube also provides electron gun means generating three electron beams arranged in a common horizontal plane. The rectangular apertures in the mask, as well as the elemental phosphor stripes, are substantially straight and vertical on or near the vertical axis of the mask looking from the direction of the central axis of the tube, but gradually curve with an increasing curvature in the direction laterally from the center out toward the periphery of the mask.
A STRIPED PHOSPHOR SCREEN
ABSTRACT OF THE DISCLOSURE
This invention provides a color cathode ray tube which includes a curved screen provided with elemental phosphor stripes substantially vertically oriented, and running cyclically red, green and blue. Spaced inwardly from the screen is a shadow mask containing small rectangular apertures, and the cathode ray tube also provides electron gun means generating three electron beams arranged in a common horizontal plane. The rectangular apertures in the mask, as well as the elemental phosphor stripes, are substantially straight and vertical on or near the vertical axis of the mask looking from the direction of the central axis of the tube, but gradually curve with an increasing curvature in the direction laterally from the center out toward the periphery of the mask.
Description
108~810 BACKGROUND OF THE INVENTION
This invention relat~s to an improved color cathode ray tube~ and more particularly to a color cathode ray tube in which the improved shadow mask having apertures in the form of slits and the improved screen having smooth edged continuous elemental phosphor stripes are used to give a sufficient electron beam landinq tolerance, especially near the edges of the screen.
B~IEF DESC~IrTION OF THE D~A~INGS
10In the accompanying drawings, in which like numerals denote like parts throughout the several views, Fig. 1 is a fragmentary perspective view of a prior art color cathode ray tube;
Fig. 2 is an enlarged rear elevational view of the screen of the tube of Fig. l;
Fig. 3 is a perspective view, partly cut awa~, of a color cathode ray tube according to this invention;
' Fig. 4 is a perspective diagram useful in explaining ~ ' the relation between the arrangemRnt of the ma,sk apertures 20 and the long light source according to this invention; , Fig~ 5 is a fragmentary elevational showing the intersection lines on a spherical shadow mask according to Fig. 4;
Fig. 6 is a fragmentary elevational showing t~e arrangement of the mask apertures according to Fig~ 5;
Fig. 7 is a fragmentary enlarged view of the mask apertures according to another embodiment of this inventionO
Descri~tion of Prior Art:
Conventional color cathode ray tubes employ an, ' 30 electroluminescent screen consisting of circular phosphor dots surrounded by light absorbing material, and a shadow mask having a circular aperture corresponding to each triad o , .
phosphor dots as explained in United States Patent No. 3,146,368, issued August 25, 1964 to Rauland Corporation, invented by J.D. Fiore and S.H~ Kaplan. This screen construction is advantageous to produce an imaye of enhanced brightness and greater contrast. However, the conventional color cathode ray tubes have some difficulties such as necessity of particular consideration being given to electron beam landing tolerance and necessity of many complex adjusting attachments, especially beam convergence is complex.
A color ca~hode ray tube of a new type, called "in-line"
gun type has been developed to eliminate such difficulties.
It has an image screen including a plurality of phosphor stripes spaced from each other by intermediate stripes made of light absorbing material, a slotted shadow mask adjacent to the screen and an electron gun means for projecting a central beam and a pair of side beams which are disposed in the same plane.
With reference to Fig. 1 of the accompanying drawings which shows a new type color cathode ray tube including a phosphor screen (11) coated on the inner surface of a face 20 plate, a plurality of elemental phosphor stripes are arranged cyclically, green, blue and red color phosphor stripes (12G), (12B) and (12R), respectively, and light absorbing stripes (13) a~e placed between and adjoining the color phosphor stripes (12G), (l~B) and (12R).
The shadow mask (14) of this new tube have a plurality of small rectangular apertures (15) being vertically spaced apart by thin traverse bridge portions (16). These thin bridge portions are significant in pressing the mask into a spherical contour. The three electron guns of this tube are placed horizontally adjacent in a so-called in-line configuration.
It has been recognized that such a color cathode ray tube provided with a striped color phosphor screen, and a .
slotted aperture mask has higher color picture qualities than a conventional color cathode ray tube provided with a circular dot type phosphor screen. Namely, it is capable of reproducing a much brighter image and easy adjustment of its color purity.
This newly developed color cathode ray tube, however, has problems in the manufacturing process of the phosphor screen as are mentioned hereinbelowO
The phosphor screen of this new tube is made b~ a photographic method, using photosensitive resin on the surface of the panel, the above mentioned shadow mask having a plurality of 6mall rectangular beam passable apertures, and using a long light source for projecting bright images of the apertures onto the surface of the panel.
Though there are bridge portions at which the light beam is i~tercepted in the row of apertures, the phosphor stripe which is to be formed on the panel sur~ace by the bright image of the apertures must be continuous throughout the vertical length of ~he screen. By using an elongated light source being parallel to the horizontal axis of the tube~ a continuous , 20 stripelike bright image corresponding to the whole length of the row of the mask apertures is acquiredi the dark image of the bridge portion which is projected on the panel by the light beam from an end of the light source is overlapped by a bright image of the light coming through the aperture made from - another end of the light source.
In rectangular color cathode ray tubes, the stripes ... .
of bright images of the mask apertures produced on the panel , -~ as above are sufficiently straight and uniform in width on and near the vertical and horizontal axis of the panel. But, in ~- 30 the corner regions of the panel, the stripes of bright images . .
- become considerably zigzagged and non-uniform in width. Con-~- sequently, phosphor stripes in the corner regions are zigzagged .
- 4 ~
8~b and non-uniform in width as shown in Fig. 2, resulting in decrease in quality of color picture reproduced by the screen.
Especially, the sufficient beam landing tolerance is required near the corner of the screen. Consequently it is very important to eliminate the non-uniformity in width of the color phosphor stripes or the light absorbing stripes near the corner of the screen. It was found that the zigzagged form of the stripe images produced on the corner regions of the panel is due to the angular difference between the tangent face of each m~sk apertures in the lengthwise direction of the aperture rows and the long axis of the light source. As a result, we have improved the color tube by using the improved shadow mask.
SUMMARY OF THE INVENTION
Accordingly, this invention provides a color cathode ray tube comprising: a curved spherical panel having a screen with different elemental color phosphor stripes running cyclically on its inner surface, a shadow mask adjacent the screen and having substantially the same curvature as said screen, said mask having a number of beam-passable apertures -- arranged in rows, said apertures along the length of each of said rows being separated from ~ach other by narrow beam-intercepting bridge portions, first means for generating three electron beams which are arranged in-line horizontally and are directed toward said screen for impinging on corresponding phosphor stripes respectively, second means adjacent said first means for deflecting said beams, said phosphor stripes and the arranging row of apertures being substantially straight and vertical on and near the vertical axis of the mask as viewed in the direction of the central axis of the tube, and the remainder of said phosphor stripes and the arranging rows being outwardly curved in the horizontal axis direction, the 'A~
curvature being concave toward the mask center and gradually : increasing from the center to the periphery of the shadow mask.
In accordance with another aspect of this invention there is provided a cathode-ray tube for displaying coloured pictures comprising in an evacuated envelope means to generate at least two electron beams having undeflected portions with axes which are located in a first horizontal flat plane, a display screen comprising a large number of linear regions luminescing in at least two different colours, and a colour selection electrode which is curved in two directions and comprises a large number of elongate apertures which are arranged in rows corresponding to the said linear luminescent regions, said electron beams being each associated with lumi-nescent regions of one colour by means of the said colour selection electrode, characterized in that each of the said rows of apertures has a center line which is located sub-stantially in a second vertical flat plane with a line which, in an apparent deflection point of one of the said electron beams, intersects the said first horizontal flat plane through the axes of the undeflected portions of the electron beams at right angles.
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, ` 108~;810 DETAILED DESCRIPTION OF THE INV~NTION
For a better understanding of this invention, a description will be given of a color cathode ray tube in which the screen has light absorbing stripes Fig. 3 shows a color cathode ray tube of in-line gun type according to this invention. A rectangular-shaped glass panel (31) has, on its inner surface, an electroluminescent ` screen (32) comprising alternating light absorbing stripes (33) and elemental color phosphor stripes (34), (35) and (36), as ; 10 will be described in particular hereinafter, arranged in an outwardly curved pattern in a vertical direction or Y-axis of the tube.
ji A shadow mask (37) of a shape substantially corres-;~ ponding to the panel is located inside the panel (31). The , panel is fixed to a funnel (38) to construct an evacuated envelope of the tube.
'.! The funnel (38) has, in its neck portion, an electron ~;j gun means (39) for emitting three electron beams (40), (41) ^ ~ and ~42) arranged in line in a common horizontal plane con-taining X-axis of the tube. These electron beams are deflected horizontaIly and vertically by deflection means (43), and are ., i thereby caused to scan a curved spherical screen (32) through ~,, a shadow mask (37).
The shadow mask (37) has a number of small rectangular apertures (44) which are arranged in rows to vertical direction or Y-axis of the tube. The apertures (44) in each of the rows ... . .
~ ~ are aligned lengthwise, as if a very long continuous opening . .; - .
of the same width as that of it is divided into many apertures `~ by very narrow bridge portions (45) of about 0.1 mm in width, for example.
,:
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~ ~ - 6 -.~ . , .
''~ ' las6sl0 In a conventional shadow mask having slit apertures, each row of the mask aperturesare arranged in parallel to the vertical or Y-axis of the tube over the whole effective area of the shadow mask. But, in this invention, the rows of the mask apertures arranged on the center region of the mask are substantially parallel to the vertical axis of the tube and the remainder of said rows of the mask apertures are transversely curved with a curvature which is gradually increasing outwardly from the center of the mask in the horizontal direction or X-axis of the tube.
The light absorbing stripes (33) and the elementalcolor phosphor stripes (34), (35) and (36) are formed by the usual light printing method employing a light beam passing through the said shadow mask (37).
The detail arrangement of the mask apertures will be hereinbelow discussed with reference to Fig. 4 which shows a relationship between the arranging row of the mask apertures and the long light source for forming the screen. The long light source (46) is positioned at the deflection center of the electron beams as viewed from the panel in the direction of the central axis or Z~axis of the tvbe.
To make a striped screen, the panel (not shown) with the shadow mask (37) attached thereon is placed with its inner surface downward on the top of an exposing box (not .
shown). A light source having a long slit window (46) is provided on the bottom of the box for projecting light onto the inner surface of the panel through the shadow mask (37)~ -~
In this invention, the rectangular apertures of the shadow mask are arranged along the intersection lines (48) 3D which are produced with a flat plana (47) containing a long axis L of the light source (46) intersects with the shadow mask (37).
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Fig. 5 shows the intersection lines (48) as viewed in the direction of the central axis z of the tube accordlng to Fig. 4.
The intersection lines (48a) produced on and near the Y-axis of the mask are almost straight or parallel to the Y-axis. Ana the intersection lines (48b) produced near the corner or far from the Y-axis are curved outwardly in the X-axis direction with gradually increasing its curvature because the mask has an outwardly curved spherical face.
The intersection line (48~ is an arc of ellipse when viewed from the Z-axis direction and is expressed as follows:
{R + lR-M)2 _ 2(R-M) ~ ~ x2 + Xo2y2 + 2Xo(R-U) ~-(R-M)~ /R2-Xo2 ~ X + Xo2 ~ (R-M)2-R2~ - 0 ...(1) Eliminating X by converting (xo-d), Xo2y~ - 2R2Xo~ + ~(R-M- ~R2 _ Xo ) + Xo } c~ = O .,. (2) where R is the radius of curvature of the spherical mask (37), and M is the distance from the deflection center of the electron beams to the center of the mask as shown in Fig~ 4, Fig. 6 shows an arrangement of the aperture (44) of the shadow mask (37) being aligned along the intersection lines as explained in Figs. 4 and 5.
According to this arrangement of the mask apertures, the light emitted from the light source is projected on the inner surface of the panel along a flat plane which is containing said intersection line (48) and said long axis L of the light source as explained in Fig. 4.
Therefore, it is impossible to eliminate the non~
uniformity in width of the bright stripe images due to the angular difference between the tangent face of each mas~
apertures and the long axis L of the light source.
A striped screen on the panel is made by the light printing method using the above described shadow mask. There ~ i .
fore, the light absorbing stripes and the elemental color stripes are formed with a pattern corresponding to the inter-section lines (48) of the shadow mask in Fig. 6. That is, the stripes are substantially straight on and near the Y-axis of the screen, and are curved gradually increasing in curvature outwardly in the X-axis direction from the screen center.
Fig. 7 shows the another embodiment of the arrangement of the mask apertures according to this invention.
The mask (37) has the very narrow bridge portions ~50) which are substantially parallel to the X-axis of the tube to prevent moire phenomena.
Therefore, the mask apertures (52) arranged near the corner of ~he mask become a parallelogram configuration.
As above mentioned, according to this invention, the electroluminescent screen has smooth edged continuous color phosphor stripes over the effective area of the screen. And a color cathode tube according to this invention has sufficient beam landing tolerance near the corners of the screen and has higher color picture qualities. While in the above des-cribed embodiment the color cathode ray tube has an ou~wardlycurved spherical screen and a spherical shadow mask, the configuration of the screen and the mask may vary from spherical `~ to cylindrical.
In addition to a color cathode ray tube having a light absorbing stripe type screen, this invention is also applicable to other color cathode ray tube in which the screen ha~i ollly color phosphor :~tripe~.
This invention relat~s to an improved color cathode ray tube~ and more particularly to a color cathode ray tube in which the improved shadow mask having apertures in the form of slits and the improved screen having smooth edged continuous elemental phosphor stripes are used to give a sufficient electron beam landinq tolerance, especially near the edges of the screen.
B~IEF DESC~IrTION OF THE D~A~INGS
10In the accompanying drawings, in which like numerals denote like parts throughout the several views, Fig. 1 is a fragmentary perspective view of a prior art color cathode ray tube;
Fig. 2 is an enlarged rear elevational view of the screen of the tube of Fig. l;
Fig. 3 is a perspective view, partly cut awa~, of a color cathode ray tube according to this invention;
' Fig. 4 is a perspective diagram useful in explaining ~ ' the relation between the arrangemRnt of the ma,sk apertures 20 and the long light source according to this invention; , Fig~ 5 is a fragmentary elevational showing the intersection lines on a spherical shadow mask according to Fig. 4;
Fig. 6 is a fragmentary elevational showing t~e arrangement of the mask apertures according to Fig~ 5;
Fig. 7 is a fragmentary enlarged view of the mask apertures according to another embodiment of this inventionO
Descri~tion of Prior Art:
Conventional color cathode ray tubes employ an, ' 30 electroluminescent screen consisting of circular phosphor dots surrounded by light absorbing material, and a shadow mask having a circular aperture corresponding to each triad o , .
phosphor dots as explained in United States Patent No. 3,146,368, issued August 25, 1964 to Rauland Corporation, invented by J.D. Fiore and S.H~ Kaplan. This screen construction is advantageous to produce an imaye of enhanced brightness and greater contrast. However, the conventional color cathode ray tubes have some difficulties such as necessity of particular consideration being given to electron beam landing tolerance and necessity of many complex adjusting attachments, especially beam convergence is complex.
A color ca~hode ray tube of a new type, called "in-line"
gun type has been developed to eliminate such difficulties.
It has an image screen including a plurality of phosphor stripes spaced from each other by intermediate stripes made of light absorbing material, a slotted shadow mask adjacent to the screen and an electron gun means for projecting a central beam and a pair of side beams which are disposed in the same plane.
With reference to Fig. 1 of the accompanying drawings which shows a new type color cathode ray tube including a phosphor screen (11) coated on the inner surface of a face 20 plate, a plurality of elemental phosphor stripes are arranged cyclically, green, blue and red color phosphor stripes (12G), (12B) and (12R), respectively, and light absorbing stripes (13) a~e placed between and adjoining the color phosphor stripes (12G), (l~B) and (12R).
The shadow mask (14) of this new tube have a plurality of small rectangular apertures (15) being vertically spaced apart by thin traverse bridge portions (16). These thin bridge portions are significant in pressing the mask into a spherical contour. The three electron guns of this tube are placed horizontally adjacent in a so-called in-line configuration.
It has been recognized that such a color cathode ray tube provided with a striped color phosphor screen, and a .
slotted aperture mask has higher color picture qualities than a conventional color cathode ray tube provided with a circular dot type phosphor screen. Namely, it is capable of reproducing a much brighter image and easy adjustment of its color purity.
This newly developed color cathode ray tube, however, has problems in the manufacturing process of the phosphor screen as are mentioned hereinbelowO
The phosphor screen of this new tube is made b~ a photographic method, using photosensitive resin on the surface of the panel, the above mentioned shadow mask having a plurality of 6mall rectangular beam passable apertures, and using a long light source for projecting bright images of the apertures onto the surface of the panel.
Though there are bridge portions at which the light beam is i~tercepted in the row of apertures, the phosphor stripe which is to be formed on the panel sur~ace by the bright image of the apertures must be continuous throughout the vertical length of ~he screen. By using an elongated light source being parallel to the horizontal axis of the tube~ a continuous , 20 stripelike bright image corresponding to the whole length of the row of the mask apertures is acquiredi the dark image of the bridge portion which is projected on the panel by the light beam from an end of the light source is overlapped by a bright image of the light coming through the aperture made from - another end of the light source.
In rectangular color cathode ray tubes, the stripes ... .
of bright images of the mask apertures produced on the panel , -~ as above are sufficiently straight and uniform in width on and near the vertical and horizontal axis of the panel. But, in ~- 30 the corner regions of the panel, the stripes of bright images . .
- become considerably zigzagged and non-uniform in width. Con-~- sequently, phosphor stripes in the corner regions are zigzagged .
- 4 ~
8~b and non-uniform in width as shown in Fig. 2, resulting in decrease in quality of color picture reproduced by the screen.
Especially, the sufficient beam landing tolerance is required near the corner of the screen. Consequently it is very important to eliminate the non-uniformity in width of the color phosphor stripes or the light absorbing stripes near the corner of the screen. It was found that the zigzagged form of the stripe images produced on the corner regions of the panel is due to the angular difference between the tangent face of each m~sk apertures in the lengthwise direction of the aperture rows and the long axis of the light source. As a result, we have improved the color tube by using the improved shadow mask.
SUMMARY OF THE INVENTION
Accordingly, this invention provides a color cathode ray tube comprising: a curved spherical panel having a screen with different elemental color phosphor stripes running cyclically on its inner surface, a shadow mask adjacent the screen and having substantially the same curvature as said screen, said mask having a number of beam-passable apertures -- arranged in rows, said apertures along the length of each of said rows being separated from ~ach other by narrow beam-intercepting bridge portions, first means for generating three electron beams which are arranged in-line horizontally and are directed toward said screen for impinging on corresponding phosphor stripes respectively, second means adjacent said first means for deflecting said beams, said phosphor stripes and the arranging row of apertures being substantially straight and vertical on and near the vertical axis of the mask as viewed in the direction of the central axis of the tube, and the remainder of said phosphor stripes and the arranging rows being outwardly curved in the horizontal axis direction, the 'A~
curvature being concave toward the mask center and gradually : increasing from the center to the periphery of the shadow mask.
In accordance with another aspect of this invention there is provided a cathode-ray tube for displaying coloured pictures comprising in an evacuated envelope means to generate at least two electron beams having undeflected portions with axes which are located in a first horizontal flat plane, a display screen comprising a large number of linear regions luminescing in at least two different colours, and a colour selection electrode which is curved in two directions and comprises a large number of elongate apertures which are arranged in rows corresponding to the said linear luminescent regions, said electron beams being each associated with lumi-nescent regions of one colour by means of the said colour selection electrode, characterized in that each of the said rows of apertures has a center line which is located sub-stantially in a second vertical flat plane with a line which, in an apparent deflection point of one of the said electron beams, intersects the said first horizontal flat plane through the axes of the undeflected portions of the electron beams at right angles.
':
':
',' ~"
., .
~ -5a-.
, ` 108~;810 DETAILED DESCRIPTION OF THE INV~NTION
For a better understanding of this invention, a description will be given of a color cathode ray tube in which the screen has light absorbing stripes Fig. 3 shows a color cathode ray tube of in-line gun type according to this invention. A rectangular-shaped glass panel (31) has, on its inner surface, an electroluminescent ` screen (32) comprising alternating light absorbing stripes (33) and elemental color phosphor stripes (34), (35) and (36), as ; 10 will be described in particular hereinafter, arranged in an outwardly curved pattern in a vertical direction or Y-axis of the tube.
ji A shadow mask (37) of a shape substantially corres-;~ ponding to the panel is located inside the panel (31). The , panel is fixed to a funnel (38) to construct an evacuated envelope of the tube.
'.! The funnel (38) has, in its neck portion, an electron ~;j gun means (39) for emitting three electron beams (40), (41) ^ ~ and ~42) arranged in line in a common horizontal plane con-taining X-axis of the tube. These electron beams are deflected horizontaIly and vertically by deflection means (43), and are ., i thereby caused to scan a curved spherical screen (32) through ~,, a shadow mask (37).
The shadow mask (37) has a number of small rectangular apertures (44) which are arranged in rows to vertical direction or Y-axis of the tube. The apertures (44) in each of the rows ... . .
~ ~ are aligned lengthwise, as if a very long continuous opening . .; - .
of the same width as that of it is divided into many apertures `~ by very narrow bridge portions (45) of about 0.1 mm in width, for example.
,:
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~ ~ - 6 -.~ . , .
''~ ' las6sl0 In a conventional shadow mask having slit apertures, each row of the mask aperturesare arranged in parallel to the vertical or Y-axis of the tube over the whole effective area of the shadow mask. But, in this invention, the rows of the mask apertures arranged on the center region of the mask are substantially parallel to the vertical axis of the tube and the remainder of said rows of the mask apertures are transversely curved with a curvature which is gradually increasing outwardly from the center of the mask in the horizontal direction or X-axis of the tube.
The light absorbing stripes (33) and the elementalcolor phosphor stripes (34), (35) and (36) are formed by the usual light printing method employing a light beam passing through the said shadow mask (37).
The detail arrangement of the mask apertures will be hereinbelow discussed with reference to Fig. 4 which shows a relationship between the arranging row of the mask apertures and the long light source for forming the screen. The long light source (46) is positioned at the deflection center of the electron beams as viewed from the panel in the direction of the central axis or Z~axis of the tvbe.
To make a striped screen, the panel (not shown) with the shadow mask (37) attached thereon is placed with its inner surface downward on the top of an exposing box (not .
shown). A light source having a long slit window (46) is provided on the bottom of the box for projecting light onto the inner surface of the panel through the shadow mask (37)~ -~
In this invention, the rectangular apertures of the shadow mask are arranged along the intersection lines (48) 3D which are produced with a flat plana (47) containing a long axis L of the light source (46) intersects with the shadow mask (37).
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Fig. 5 shows the intersection lines (48) as viewed in the direction of the central axis z of the tube accordlng to Fig. 4.
The intersection lines (48a) produced on and near the Y-axis of the mask are almost straight or parallel to the Y-axis. Ana the intersection lines (48b) produced near the corner or far from the Y-axis are curved outwardly in the X-axis direction with gradually increasing its curvature because the mask has an outwardly curved spherical face.
The intersection line (48~ is an arc of ellipse when viewed from the Z-axis direction and is expressed as follows:
{R + lR-M)2 _ 2(R-M) ~ ~ x2 + Xo2y2 + 2Xo(R-U) ~-(R-M)~ /R2-Xo2 ~ X + Xo2 ~ (R-M)2-R2~ - 0 ...(1) Eliminating X by converting (xo-d), Xo2y~ - 2R2Xo~ + ~(R-M- ~R2 _ Xo ) + Xo } c~ = O .,. (2) where R is the radius of curvature of the spherical mask (37), and M is the distance from the deflection center of the electron beams to the center of the mask as shown in Fig~ 4, Fig. 6 shows an arrangement of the aperture (44) of the shadow mask (37) being aligned along the intersection lines as explained in Figs. 4 and 5.
According to this arrangement of the mask apertures, the light emitted from the light source is projected on the inner surface of the panel along a flat plane which is containing said intersection line (48) and said long axis L of the light source as explained in Fig. 4.
Therefore, it is impossible to eliminate the non~
uniformity in width of the bright stripe images due to the angular difference between the tangent face of each mas~
apertures and the long axis L of the light source.
A striped screen on the panel is made by the light printing method using the above described shadow mask. There ~ i .
fore, the light absorbing stripes and the elemental color stripes are formed with a pattern corresponding to the inter-section lines (48) of the shadow mask in Fig. 6. That is, the stripes are substantially straight on and near the Y-axis of the screen, and are curved gradually increasing in curvature outwardly in the X-axis direction from the screen center.
Fig. 7 shows the another embodiment of the arrangement of the mask apertures according to this invention.
The mask (37) has the very narrow bridge portions ~50) which are substantially parallel to the X-axis of the tube to prevent moire phenomena.
Therefore, the mask apertures (52) arranged near the corner of ~he mask become a parallelogram configuration.
As above mentioned, according to this invention, the electroluminescent screen has smooth edged continuous color phosphor stripes over the effective area of the screen. And a color cathode tube according to this invention has sufficient beam landing tolerance near the corners of the screen and has higher color picture qualities. While in the above des-cribed embodiment the color cathode ray tube has an ou~wardlycurved spherical screen and a spherical shadow mask, the configuration of the screen and the mask may vary from spherical `~ to cylindrical.
In addition to a color cathode ray tube having a light absorbing stripe type screen, this invention is also applicable to other color cathode ray tube in which the screen ha~i ollly color phosphor :~tripe~.
Claims (6)
1. A color cathode ray tube comprising: a curved spherical panel having a screen with different elemental color phosphor stripes running cyclically on its inner surface, a shadow mask adjacent the screen and having substantially the same curvature as said screen, said mask having a number of beam-passable apertures arranged in rows, said apertures along the length of each of said rows being separated from each other by narrow beam-intercepting bridge portions, first means for generating three electron beams which are arranged in-line horizontally and are directed toward said screen for impinging on corresponding phosphor stripes respectively, second means adjacent said first means for deflecting said beams, said phosphor stripes and the arranging row of the apertures being substantially straight and vertical on and near the vertical axis of the mask as viewed in the direction of the central axis of the tube, and the remainder of said phosphor stripes and the arranging rows being outwardly curved in the horizontal axis direction, the curvature being concave toward the mask center and gradually increasing from the center to the periphery of the shadow mask.
2. A color cathode ray tube according to claim 1, in which the color phosphor stripes of the screen are separated by light absorbing stripes.
3. A color cathode ray tube according to claim 1, in which said apertures of the mask are arranged along intersection lines which are produced where a hypothetical vertical flat plane passing through said second means intersects the shadow mask.
4. A color cathode ray tube comprising: a curved cylindrical panel having a screen with different elemental color phosphor stripes running cyclically on its inner surface, a shadow mask adjacent the screen and having substantially the same curvature as said screen, said mask having a number of beam-passable apertures arranged in rows, said apertures along the length of each of said rows being separated from each other by narrow beam-intercepting bridge portions, and means for generating three electron beams which are arranged in-line and are directed toward said screen for impinging on corresponding phosphor stripes respectively, said phosphor stripes and the arranging row of the apertures being substantially straight and vertical on and near the vertical axis of the mask as viewed in the direction of the central axis of the tube, and the remainder of said phosphor stripes and the arranging rows being outwardly curved in the horizontal axis direction, the curvature being concave toward the mask center and gradually increasing from the center to the periphery of the shadow mask.
5. A color cathode ray tube according to claim 4, in which the color phosphor stripes of the screen are separated by light absorbing stripes.
6. A color cathode ray tube according to claim 1, in which all of said narrow beam-intercepting bridge portions of the shadow mask are substantially parallel to the horizontal axis of the shadow mask.
(7) A cathode-ray tube for displaying coloured pictures comprising in an evacuated envelope means to generate at least two electron beams having undeflected portions with axes which are located in a first horizontal flat plane, a display screen comprising a large number of linear regions luminescing in at least two different colours, and a colour selection electrode which is curved in two directions and comprises a large number of elongate apertures which are arranged in rows corresponding to the said linear luminescent regions, said electron beams being each associated with luminescent regions of one colour by means of the said colour selection electrode, characterized in that each of the said rows of apertures has a center line which is located substantially in a second vertical flat plane with a line which, in an apparent deflection point of one of the said electron beams, intersects the said first horizontal flat plane through the axes of the undeflected portions of the electron beams at right angles.
(7) A cathode-ray tube for displaying coloured pictures comprising in an evacuated envelope means to generate at least two electron beams having undeflected portions with axes which are located in a first horizontal flat plane, a display screen comprising a large number of linear regions luminescing in at least two different colours, and a colour selection electrode which is curved in two directions and comprises a large number of elongate apertures which are arranged in rows corresponding to the said linear luminescent regions, said electron beams being each associated with luminescent regions of one colour by means of the said colour selection electrode, characterized in that each of the said rows of apertures has a center line which is located substantially in a second vertical flat plane with a line which, in an apparent deflection point of one of the said electron beams, intersects the said first horizontal flat plane through the axes of the undeflected portions of the electron beams at right angles.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP47086354A JPS5244511B2 (en) | 1972-08-30 | 1972-08-30 | |
| JP86354/1972 | 1972-08-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1086810A true CA1086810A (en) | 1980-09-30 |
Family
ID=13884535
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA179,953A Expired CA1086810A (en) | 1972-08-30 | 1973-08-30 | Color cathode ray tube having a striped phosphor screen |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US3889145A (en) |
| JP (1) | JPS5244511B2 (en) |
| CA (1) | CA1086810A (en) |
| DE (1) | DE2343777B2 (en) |
| FR (1) | FR2198259B1 (en) |
| GB (1) | GB1445619A (en) |
| IT (1) | IT993840B (en) |
| NL (1) | NL172704B (en) |
Families Citing this family (27)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4070596A (en) * | 1971-08-27 | 1978-01-24 | Tokyo Shibaura Electric Co., Ltd. | In-line plural beams cathode ray tube having color phosphor element strips spaced from each other by intervening light absorbing areas and slit-shaped aperture mask |
| NL7303077A (en) * | 1973-03-06 | 1974-09-10 | ||
| JPS6024533B2 (en) * | 1973-12-10 | 1985-06-13 | 日本電気株式会社 | How to make a shadow mask |
| JPS5727574B2 (en) * | 1974-03-13 | 1982-06-11 | ||
| US4136300A (en) * | 1975-03-19 | 1979-01-23 | Rca Corporation | Cathode ray tube having improved shadow mask |
| CA1065003A (en) * | 1975-05-05 | 1979-10-23 | Albert M. Morrell | Cathode ray tube having improved line-screen structure |
| JPS5224073A (en) * | 1975-07-15 | 1977-02-23 | Nec Corp | Color braun tube use shadow mask plate |
| NL7602752A (en) * | 1976-03-17 | 1977-09-20 | Philips Nv | EXPOSURE DEVICE FOR MANUFACTURING DISPLAYS OF COLOR TV DISPLAY TUBES AND DISPLAY TUBE MADE WITH SUCH A DEVICE. |
| JPS5310961A (en) * | 1976-07-19 | 1978-01-31 | Hitachi Ltd | Color picture tube |
| DE2656995C2 (en) * | 1976-12-16 | 1983-12-01 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Rectangular color selection mask for a color cathode ray tube |
| NL7703233A (en) * | 1977-03-25 | 1978-09-27 | Philips Nv | TELEVISION DISPLAY TUBE. |
| NL7711713A (en) * | 1977-10-26 | 1979-05-01 | Philips Nv | COLOR IMAGE TUBE. |
| US4181870A (en) * | 1978-03-08 | 1980-01-01 | Zenith Radio Corporation | Assembly of electron guns having different gamma values |
| DE2833092A1 (en) * | 1978-07-28 | 1980-02-07 | Licentia Gmbh | Colour picture tube with slotted mask - uses phosphor vertical strips which have constrictions lying in electron shadow of slotted mask transversal links |
| GB2052144A (en) * | 1979-06-27 | 1981-01-21 | Ibm | Shadow mask colour television tubes |
| NL8005409A (en) * | 1980-09-30 | 1982-04-16 | Philips Nv | COLOR IMAGE TUBE. |
| US4568162A (en) * | 1983-08-19 | 1986-02-04 | Rca Corporation | Method for screening line screen slit mask color picture tubes |
| US4516841A (en) * | 1983-08-19 | 1985-05-14 | Rca Corporation | Method for screening line screen slit mask color picture tubes |
| SU1461377A3 (en) * | 1984-05-25 | 1989-02-23 | Рка Корпорейшн (Фирма) | Colour kinescope |
| JP2534644B2 (en) * | 1984-09-13 | 1996-09-18 | 株式会社東芝 | Color picture tube |
| JPS644793Y2 (en) * | 1984-10-12 | 1989-02-07 | ||
| US4697119A (en) * | 1985-01-11 | 1987-09-29 | Kabushiki Kaisha Toshiba | Color cathode ray tube having a non-spherical curved mask |
| IN165336B (en) * | 1985-03-14 | 1989-09-23 | Rca Corp | |
| US4691138A (en) * | 1985-03-14 | 1987-09-01 | Rca Corporation | Color picture tube having shadow mask with varied aperture column spacing |
| US4631441A (en) * | 1985-03-14 | 1986-12-23 | Rca Corporation | Color picture tube having improved line screen |
| US4634247A (en) * | 1985-12-19 | 1987-01-06 | Rca Corporation | Method for screening line screen slit mask color picture tubes |
| TW297907B (en) * | 1994-07-14 | 1997-02-11 | Toshiba Co Ltd |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL212758A (en) * | 1955-12-07 | |||
| NL262149A (en) * | 1961-03-08 | |||
| CA921540A (en) * | 1968-11-21 | 1973-02-20 | Fuse Yuzo | Shadow mask |
| US3790839A (en) * | 1972-04-04 | 1974-02-05 | Zenith Radio Corp | Rectangular grade black surround screen |
-
1972
- 1972-08-30 JP JP47086354A patent/JPS5244511B2/ja not_active Expired
-
1973
- 1973-08-29 GB GB4057973A patent/GB1445619A/en not_active Expired
- 1973-08-30 IT IT28400/73A patent/IT993840B/en active
- 1973-08-30 US US393028A patent/US3889145A/en not_active Expired - Lifetime
- 1973-08-30 NL NLAANVRAGE7311931,A patent/NL172704B/en not_active Application Discontinuation
- 1973-08-30 CA CA179,953A patent/CA1086810A/en not_active Expired
- 1973-08-30 DE DE19732343777 patent/DE2343777B2/en not_active Ceased
- 1973-08-30 FR FR7331402A patent/FR2198259B1/fr not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| IT993840B (en) | 1975-09-30 |
| DE2343777A1 (en) | 1974-03-14 |
| NL7311931A (en) | 1974-03-04 |
| GB1445619A (en) | 1976-08-11 |
| JPS4943568A (en) | 1974-04-24 |
| NL172704B (en) | 1983-05-02 |
| JPS5244511B2 (en) | 1977-11-08 |
| US3889145A (en) | 1975-06-10 |
| FR2198259B1 (en) | 1977-08-05 |
| FR2198259A1 (en) | 1974-03-29 |
| DE2343777B2 (en) | 1976-12-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |