Note the big deflection unit !
GRUNDIG SUPER COLOR 1510a CHASSIS 29301-374.01(01) CRT TUBE TOSHIBA 370BDB22. IN-LINE TYPE TRIPLE ELECTRON GUN ASSEMBLY:An in-line type triple electron gun assembly which comprises three electron gun members arranged in the same plane with the axis of the side gun members inclined at a predetermined angle to that of the central gun member; and support members fitted to the gun members for their integral assembly, said support member comprising two longitudinal elements each disposed between two adjacent gun members and at least one bridge element connecting said two longitudinal elements.
An
in-line type triple electron gun assembly comprising: 2. An electron
gun assembly according to claim 1 wherein said at least one lateral
component of at least one of the support members is fused to the cathode
electrodes and plane grid electrodes of electron gun members. 3. An
electron gun assembly according to claim 1 wherein said at least one
lateral component of at least one of the support members is fused to the
cathode electrodes and plane grid electrodes of all of the electron
gun members. 4. An electron gun assembly according to claim 1 wherein
each of said support members is generally H-shaped and comprises two
longitudinal components and a lateral component bridging said two
longitudinal components. 5. An electron gun assembly according to claim 4
wherein said lateral component of at least one of the H-shaped support
members is fused to the cathode electrode and plane grid electrodes of
electron gun members. 6. An electron gun assembly according to claim 4
wherein said lateral component of at least one of the H-shaped support
members is fused to the cathode electrode and plane grid electrodes of
all of the electron gun members. 7. An electron gun assembly according
to claim 4 wherein said generally H-shaped support members each
include a metal support member bridging the ends of the longitudinal
components thereof. 8. An electron gun assembly according to claim 5
wherein said generally H-shaped support members each include a metal
support member bridging the ends of the longitudinal components
thereof. 9. An electron gun assembly according to claim 1 wherein each
of said support members comprises one longitudinal component and a
plurality of lateral components integrally connected to said
longitudinal component. 10. An electron gun assembly according to claim
9 wherein at least one of said lateral components is fused to the
cathode electrodes and plane grid electrodes of electron gun members.
The prior art in-line type triple electron gun assembly is fabricated by fitting glass beads to the prescribed positions between two adjacent ones of three electron gun members arranged in the same plane by the aid of brackets fitted to grid electrodes constituting each electron gun member so as to fix together the three electron gun members.
With the prior art in-line type triple electron gun assembly, the glass beads are provided separately from each other, making the relative position of the gun members unstable and in consequence giving rise to their mutual displacement. Particularly, the brackets fitted to the grid electrodes constituting each gun member are bent intricately and subject to a certain degree of mechanical stress during fabrication, so that application of heat required for the assembly of gun members most likely deforms the brackets. Though very slight for the individual brackets, this deformation assumes a prominent proportion for all the brackets, resulting in the noticeable displacement of the electron gun assembly as a whole. This displacement of the constituent gun members occurs particularly in their axial direction, leads to the irregular arrangement of its grid electrodes.
SUMMARY OF THE INVENTION
According to this invention, triple electron gun members each having a cathode electrode, plane grid electrode and cylindrical electrodes coaxially arranged in succession are placed side by side in the same plane with a prescribed convergence angle defined therebetween. To both sides of the electron gun assembly are fused two support members to hold the respective gun members securely in place. Each support member comprises at least one lateral or bridging component fused in common to at least the cathode electrodes and plane grid electrodes of the respective electron gun members and at least one longitudinal component intersecting said at least one lateral component at right angles and fitted in common to said electron gun members through the later described means which are fused to said electron gun members.
The present invention can be more fully understood from the following detailed description when taken in connection with the accompanying drawings, in which:
FIG. 1 is a side view of an in-line type triple electron gun assembly according to the first embodiment of this invention;
FIG. 2 is a sectional view on line 2--2 of the electron gun assembly of FIG. 1;
FIG. 3 is a perspective view of a plane grid electrode of a side electron gun member;
FIG. 4 is a perspective view of a plane grid electrode of a central electron gun member;
FIG. 5 is a side view of a triple electron gun assembly according to the second embodiment of the invention; and
FIG. 6 is a sectional view on line 6--6 of the triple electron gun assembly of FIG. 5.
The H-shaped support member 19 is so designed that when it is fused to the electron gun assembly 11, the lateral component 19b bridging the two longitudinal components 19a is so positioned as to face the first grid electrode and cathode electrode of each electron gun member 12. As shown in FIG. 1. lateral component 19b is integral with (i.e., integrally connected to) components 19a and is made of the same material as components 19a. Said H-shaped support member 19 is fitted to the electron gun assembly 11 through the support member 20 of the cathode electrodes 13, the holders 23 and 25 of the first plane grid electrodes 14s and 14c, and brackets 26 fused to the cylindrical grid electrodes 15 to 17. A metal support element 19C bridges the ends of the H-shaped support member 19.
According
to the in-line type triple electron gun assembly of this invention of
the aforementioned arrangement, the three electron gun members 12 are
fixed in place by the H-shaped support members 19, so that the
respective electron gun members 12 and the electrodes included therein
can be located accurately with the support members 19 used as the base.
Since the electron gun members 12 are substantially free from any
deformation or distortion, a beam of electrons emitted from the electron
gun members 12 can display excellent characteristics of emission and
focusing simply by slightly adjusting an external magnetic field.
Further, the electrodes of the electron gun members 12 are independently
supported by the H-shaped support members 19, so that the brackets 26
are required to hold only the grid electrodes to which they are fused,
namely, are not subject to any extra load. Therefore, the brackets 26
can be made of thin light material having a relatively small mechanical
strength. This offers various advantages that the brackets 26 can be
easily fabricated; work stress occurring in the brackets 26 is reduced;
when the thin brackets 26 are fused to the electrodes the roundness of
said electrodes is little affected; and the electron lens constituted
by the electron gun members is substantially free from aberration.The
lateral component 19b of the H-shaped support member 19 is fused to
the first plane grid electrode and cathode electrode of each electron
gun member, thereby minimizing the deformation of the mechanically weak
first plane gride electrode which would occur when the triple electron
gun members are assembled and the harmful effect of displacement
caused by said distortion between the axis of the first grid electrode
and those of the other grid electrodes. Further, the above-mentioned
lateral component 19b plays the part of elevating the overall
mechanical strength of the electron gun members constituting the
in-line type electron gun assembly which is mechanically weaker than
the delta-shaped type.
The electron gun assembly of the second embodiment shown in FIG. 5 attains not only the same effect as the first embodiment but also displays the following advantage that since the lateral components support the crosswise groups each consisting of three juxtaposed grid electrodes operated with the same potential, the electrodes of the lengthwise groups operated with different potentials can be spaced relatively far from each other, thereby elevating the degree of insulation therebetween.
MAGNETIC CONVERGENCE DEVICE FOR USE IN AN IN-LINE TOSHIBA CRT TYPE COLOR CATHODE RAY TUBE:
Explanation of the Convergence Unit on Toshiba CRT Tube;
A pair of E-shaped cores are mounted radially in opposite directions on the outer surface of a neck portion of an inline type color cathode ray tube. Each of the E-shaped cores has a center leg and two side legs about which dynamic convergence coils are wound in radial arrangement relative to the neck portion so as to converge electron beams from the cathode ray tubes along the longitudinal direction of the center legs of the respective cores. First and second disc-shaped permanent magnets are rotatably mounted on a cross-piece connecting the one side ends of the respective legs, and provide adjustable static fluxes cooperating with the dynamic convergence flux by travelling through the center and side legs and across the open ends thereof.
1. A magnetic convergence device for use in an in-line type color cathode ray tube comprising:
2. A magnetic convergence device as claimed in claim 1 wherein each of said E-shaped cores has a cross-piece separated into first, second and third divisions respectively connected to said center and side legs with first and second magnetic gaps provided between the adjacent ones of said divisions; and said permanent magnets are so positioned as to bridge the magnetic gaps.
3. A magnetic convergence device as claimed in claim 1 wherein said means for rotatably supporting the permanent magnets has two supporting members, each of which is pivotally mounted on said frame and has an adjusting wheel, a rod member with a rectangular head, each of said magnets having a rectangular bore for slidably receiving said rectangular head, and a spring member for resiliently pressing said magnet against said cross-piece.
4. A magnetic convergence device as claimed in claim 3 wherein the first and second adjusting wheels included in said two supporting members are positioned at different distances from the end wall of the frame.
5. A magnetic converence device as claimed in claim 4 wherein the peripheral portions of the first and second adjusting wheels overlap each other as viewed in the lengthwise direction of the convergence device.
6. A magnetic convergence device as claimed in claim 4 wherein said first and second adjusting wheels are so disposed as to prevent their peripheral portions from overlapping each other as viewed in the lengthwise direction of the convergence device.
7. A magnetic convergence device as claimed in claim 1 wherein said means for rotatably supporting the permanent magnets include supporting rods secured to said frame, said magnets having bores for rotatably receiving the free end of said supporting rods and spring members for resiliently pressing said magnets against said cross-piece.
8. A magnetic convergence device as claimed in claim 1 wherein said means for rotatably supporting the permanent magnets include spring members stretched between said frame and permanent magnets for resiliently pressing said magnets against said cross-piece.
9. A magnetic convergence device as claimed in claim 8 wherein said spring member is a compression coil spring.
10. A magnetic convergence device as claimed in claim 8 wherein said spring member is a hook-shaped leaf spring, the curved portion thereof engaging the surface of said magnets and the straight portion being secured to said frame.
11. A magnetic convergence device as claimed in claim 1 comprising four disc-shaped permanent magnets, and wherein said means for rotatably mounting said magnets includes means for rotatably mounting two of said permanent magnets on respective cross-pieces of each of said E-shaped cores.
An in-line type color cathode ray tube has recently come into use as a color cathode ray tube. The in-line type tube generally has three electron guns arranged in linear relationship, and the electron beams emitted from the guns are directed to a fluorescent screen through the neck portion keeping the in-line arrangement of said electron guns. Among these beams, the center beam is usually for a green color and the two side beams are respectively for red and blue colors. To provide a clear and proper color picture over the entire area of the fluorescent screen, it is necessary for the three electron beams convergently to impinge on a given small area of the fluorescent screen. For this purpose, a dynamic convergence means and a static convergence means cooperating therewith are generally provided on the outer surface of the neck portion in connectqon with the red and blue color electron beams. Further, the red and blue color electron beams should be deflected all over the fluorescent screen so as to obtain a good beam convergence, but any of the conventional convergence devices has failed to effect proper deflection.
Accordingly, it is an object of this invention to provide a magnetic convergence device for use in an in-line type color cathode ray tube capable of adjusting the convergence of multiple electron beams accurately and uniformly.
SUMMARY OF THE INVENTION
In
accordance with this invention, the above-mentioned object can be
achieved by providing a magnetic convergence device for use in an
in-line tupe color cathode ray tube comprising a pair of E-shaped cores,
each of said cores having a center leg, two side legs and a
cross-piece connecting the ends of said center and said legs; a
nonmagnetic frame having a tubular member for mounting said E-shaped
cores radially in facing relationship on the outer surface of the neck
portion of said cathode ray tube; dynamic convergence coils wound about
said legs for generating a dynamic convergence flux therethrough; two
disc-shaped permanent magnets for creating an adjustable static flux
cooperating with said dynamic convergence flux by travelling through
said legs and across the open ends thereof; and means for rotatably
mounting said permanent magnets on said cross-piece of at least one of
said E-shaped cores.The present invention can be more fully understood from the following detailed description when taken in connection with the accompanying drawings, in which:
FIG. 1 is a front view of a magnetic convergence device according to an embodiment of this invention;
FIG. 2 is a side view, partly in section, along line 2--2 of FIG. 1;
FIG. 3 is a schematic front view of the magnetic convergence device of FIG. 1, presenting the operation thereof;
FIG. 4 shows a modification of the convergence adjusting mechanism of the device of FIG. 1;
FIGS. 5 to 7 show other modifications of the static convergence adjusting mechanism of the device of FIG. 1; and
FIG. 8 is a fractional schematic front view of another embodiment of the invention.
Referring
to FIGS. 1 and 2 of the accompanying drawings, a mounting frame 10 is
made of a nonmagnetic material, preferably a plastic material. The
mounting frame 10 has a tubular member 11 fitted around the outer
surface of the neck portion 12 of an in-line type color cathode ray
tube. The three electron beams 13, 14 and 15 representing red, green and
blue colors of the color cathode ray tube are aligned in line with one
another and separated by magnetic shield plates 16 and 17 so as to
prevent interaction between the magnetic fields applied to the
respective electron 13 to 15. The beams, in particular the beams 13 and
15, are therefore independently adjustable and their convergence is
controlled by magnetic assemblies 18 and 19. The assemblies 18 and 19
are positioned external to the neck portion 12 of the cathode ray tube
and adjacent to the internal magnetic shield plates 16 and 17. The
assemblies 18 and 19 create a flux for deflecting the respective beams
13 and 15. Each assembly, for example, assembly 18 comprises a dynamic
electromagnet 20 and two disc-shaped permanent magnets 21 and 22. Since
each assembly is identical in structure, description of the parts of
the assembly 18 will suffice and is applicable to those of the other
assembly 19 which are designated by the same numerals having a letter a
suffixed thereto.The dynamic electromaget 20 has an E-shaped iron core prepared by powder metallurgy and consisting of a center leg 23, two side legs 24 and 25 and a cross-piece, the cross-piece being divided into a portion 26 connected to the center leg 23 and two other portions 27 and 28 connected to the side legs 24 and 25. Further, said cross--piece has magnetic gaps formed by nonmagnetic adhesive spacers 29 and 30 disposed in the boundaries of the adjacent ones of the aforesaid three portions 26, 27 and 28. Coils 31 and 32 are wound about the side legs 24 and 25 to create an alternting flux by alternating current passing therethrough in addition to the static fluxes of permanent magnets 21 and 22.
Each dynamic electromagnet 20 is secured between side shoulders 33 longitudinally of the subject magnetic convergence device with the innermost ends of the side legs 24 and 25 tightly fitted to the inside of the top shoulders 34 so as to prevent the electromagnet 20 from unduly approaching the neck portion, that is, to allow a presecribed space therebetween.
The aforementioned shoulders 33 and 34 are formed on the frame 10 so as to support the side legs 24 and 25 and also fit the innermost ends of the legs 23 to 25 around the outer surface of the neck portion 12.
Between the dynamic electromagnet 20 and the end wall 36 of the frame 10 are provided permanent magnets 21 and 22 respectively supported by rotatable supporting members comprised of rods 39 and 40 and adjusting wheels 41 and 42. The rods 39 and 40 have projections 37 fitted into perforations 38 provided in the wall 36 of the frame 10. Between the adjusting wheels 41 and 42 and permanent magnets 21 and 22, there are wound compression coil springs 43 and 44 around the rods 39 and 40 to press the permanent magnets 21 and 22 against the crosspiece of the dynamic electromagnet 20. The permanent magnets 21 and 22 have bores 45 rectangular in cross section to allow the passage therethrough of the top portions of the rods 39 and 40 having a rectangular cross section similar to that of the bores 45. Thus the permanent magnets 21 and 22 are normally pressed against the dynamic electromagnet 20, and, when rotated by manually turning the adjusting wheels 41 and 22, can adjust the direction in which there is created a static flux therefrom. The permanent magnets 21 and 22 are respectively so positioned as to bridge the boundaries defined by the central portion 26 of the cross-piece 28 with the adjacent portions 27 and 28. The height of the side portions of the frame 10 gradually decreases toward the end wall 36 to facilitate the manual rotation of adjusting wheels 41 and 42.
There
will now be described by reference to FIG. 3 the operation of the
magnetic convergence device shown in FIGS. 1 and 2. When the permanent
magnet 21 generates a flux in the same direction, that is, the same
polarity arrangement NS as the permanent magnet 22 as shown in the left
side of FIG. 3, then the resultant compound flux F mainly passes
through the paired side legs 24 and 25 by travelling across a space
defined between their mutually facing open ends, causing the red color
electron beam 13 to be deflected in the direction indicated by the
arrow I or II. The deflecting direction I or II of the red color
electron beam 13 is determined by the directions in which the compound
flux F and said beam 13 are travelling. For example, when the compound
flux F takes a course shown by the arrow and the red color electron
beam 13 is assumed to pass from the under to the upper surface of the
drawing sheet, then said beam 13 will be deflected in the direction of
the arrow I. And if the beam 13 travels conversely from the upper to
the under surface thereof, then the beam 13 will be deflected in the
direction of the arrow II.On the other hand, when the permanent magnets 21 and 22 create fluxes in opposite polarity arrangements, for example, of SN-NS as shown in the right side of FIG. 3, then the resultant compound flux Fa passes through the center leg 23a and is thereafter divided into two portions flowing from the open end of the center leg 23a to the open ends of the side legs 24a and 25a. Further when the permanent magnets 21 and 22 create fluxes in different opposite polarity arrangements from the previous case, that is, NS-SN, then the compound flux Fa travels conversely from the open ends of the side legs 24a and 25a to the open end of the center leg 23a. Accordingly, the blue color electron beam 15 is deflected by the compound flux Fa in the direction shown by the arrow III or IV. The deflecting direction of said beam 15 is determined similarly in accordance with the directions in which the compound flux Fa and the blue color electron beam 15 are travelling.
The peripheral portions of the adjusting wheels 41 and 42 of FIG. 1 are separated as viewed in the crosswise direction of the magnetic convergence device but overlap each other as viewed in the lengthwise direction of said device.
However
as illustrated in FIG. 4, to facilitate the manual rotation of the
wheels 41 and 42, they may be so disposed as to have the peripheral
portions thereof separated as viewed in the crosswise direction of the
magnetic convergence device but prevented from overlapping each other as
viewed in the lengthwise dirction thereof as in the previous case.FIGS. 5 to 7 show the modifications of the static convergence adjusting mechanism of the magnetic convergence device of FIG. 1. The static convergence adjusting mechanism of FIG. 5 comprises a supporting rod 50 fixed to the end wall 36, the free end of the rod 50 rotatably supporting the permanent magnet 21b by being received in a bore 51 provided therein, and a compression coil spring 52 for resiliently pressing the magnet 21b against the cross-piece of the electromagnet 20.
The static convergence adjusting mechanism of FIG. 6 comprises a compression coil spring 53 stretched between the end wall 36 and permanent magnet 21 for resiliently pressing the magnet 21 against the cross-piece of the electromagnet 20 so as to permit the rotation of said magnet 21.
The static convergence adjusting mechanism of FIG. 7 comprises a hook-shaped leaf spring 54, the curved portion thereof engaging the surface of the magnet 21 so as to permit its rotation and the straight portion thereof being secured to the end wall 36.
In another embodiment of the invention of FIG. 8, an integrally formed E-shaped core 55 has side legs 56 and 57, a center leg 58 and a cross-piece 59 connecting the ends of the legs 56 to 58. Dynamic coils 60, 61 and 62 are wound about the respective legs 56 to 58. The other elements of the embodiment of FIG. 8 are operated in the same manner as those of FIG. 1 and description thereof is omitted.
The foreggoing description relates to the case where the three legs had such lengths as permitted their close abutment against the periphery of the neck portion of the color cathode ray tube, with their end faces varied accordingly.
However, this invention is also applicable even where the center and paired side legs constituting the E-shaped core have substantially the same length and cross section.
TOSHIBA MAGNETIC CONVERGENCE DEVICE FOR USE IN AN IN-LINE TYPE COLOR CATHODE RAY TUBEA
mounting plate having first and second arcuate slits is mounted on
the neck portion of an in-line type color cathode ray tube. On both
surfaces of the mounting plate are slidably disposed first and second
arcuate racks and first and second magnetic convergence units each
having an E-shaped convergence core, by means of screws passing through
the arcuate slits. First and second pinions geared to the arcuate
racks are fixed to one end of first and second shafts rotatably fitted
to the mounting plate, the other end of the shafts being fixed to
the first and second adjusting wheels. 1. A magnetic convergence device for use in an in-line type color cathode ray tube comprising a nonmagnetic mounting plate having first and second arcuate slits and a plurality of split pieces being clamped by a clamping means so as to fix said mounting plate on the outer surface of the neck portion of said cathode ray tube; first and second magnetic convergence units positioned on one surface of said mounting plate; and means for adjustably fitting said magnetic convergence units to permit their displacement along said arcuate slits, each of said magnetic convergence units having a nonmagnetic frame, a dynamic convergence electromagnet including an E-shaped core and two disc-shaped permanent magnets associated with said electromagnet. 2. A magnetic convergence device as claimed in claim 1 wherein said means for adjustably fitting said magnetic convergence units comprise first and second arcuate racks positioned on the other surface of said mounting plate; connecting means for connecting a pair of arcuate racks to a pair of magnetic convergence units through said arcuate slits; first and second pinions geared to said arcuate racks and fixed to one end of first and second shafts rotatably disposed on said mounting plate; and first and second adjusting wheels fixed to the other end of said shafts. 3. A magnetic convergence device as claimed in claim 1 wherein said means for adjustably fitting said magnetic convergence units comprises a plurality of screws for fixing said magnetic convergence units to said mounting plate through said arcuate slits, the diameter of the head of the screw being larger than the width of the arcuate slit. 4. A magnetic convergence device as claimed in claim 2 wherein said adjusting wheel is graduated on the periphery to indicate the rotating position of said magnetic convergence units on said mounting plate.
An in-line type color cathode ray tube has recently come into use as a color cathode ray tube. The in-line type tube generally has three electron guns arranged in linear relationship, and the electron beams emitted from the guns are directed to a fluorescent screen through the neck portion of said tube maintaining the in-line arrangement of said electron guns. Among these beams, the central beam is usually for a green color and the two side beams are for red and blue colors. To present a clear and proper color picture over the entire area of the screen, it is necessary for the three electron beams convergently to impinge on a given small area of the screen. For this purpose, a dynamic convergence means and a static convergence means cooperating therewith are generally provided on the outer surface of the neck portion in connection with the red and blue color electron beams so as to electrically and magnetically adjust their directions. Further, the red and blue color electron beams should be deflected individually all over the fluorescent screen so as to obtain a good beam convergence, but none of the conventional convergence devices has succeeded in effecting proper deflection.
Accordingly, it is an object of this invention to provide a magnetic convergence device for use in an in-line type color cathode ray tube capable of adjusting the convergence of multiple electron beams accurately and uniformly.
In accordance with this invention, the above-mentioned object can be achieved by providing a magnetic convergence device for use in an in-line type color cathode ray tube comprising a nonmagnetic mounting plate having first and second arcuate slits and a plurality of split pieces being clamped by a clamping means so as to fix said mounting plate on the outer surface of the neck portion of said cathode ray tube; first and second magnetic convergence units positioned on one surface of said mounting plate; means for adjustably fitting said magnetic convergence units to permit their displacement along said arcuate slits, each of said magnetic convergence units having a nonmagnetic frame, a dynamic convergence electromagnet including an E-shaped core and two disc-shaped permanent magnets associated with the electromagnet.
The present invention can be more fully understood from the following detailed description when taken in connection with the accompanying drawings, in which:
FIG. 1 is a side view of a magnetic convergence device mounted on the outer surface of the neck portion of an in-line type color cathode ray tube according to an embodiment of this invention;
FIG. 2 is a plan view taken along line II--II of FIG. 1;
FIG. 3 is a plan view taken along line III--III of FIG. 1; and
FIG. 4 is a plan view of another embodiment of the invention.
Referring to FIGS. 1 to 3 of
the
accompanying drawings, there is disposed a disc-shaped nonmagnetic
mounting plate 3 on the outer surface of a neck portion 1 of an
in-line type color cathode ray tube 2. The mounting plate 3 has a
bore 4 provided at the center into which the neck portion 1 is
inserted, and a plurality of, for example, six split pieces 5 formed
integrally with the mounting plate 3 and extending from the inner
surface of the bore 4. There is provided a clamping means consisting
of a clamping band 6 and a bolt 7 for clamping the split pieces 5 to
the neck portion 1. First and second arcuate slits 8 are formed in
the mounting plate 3 in concentric relationship with the bore 4.On one surface of the mounting plate 3 facing an electron gun assembly (not shown) disposed at one end part of the neck portion 1 are positioned first and second arcuate racks 9, which have a curvature corresponding to that of the racks, 8 and a width slightly larger than that of the slits 9. On the other surface of the mounting plate 3 facing a fluorescent screen (not shown) of the cathode ray tube 2 are positioned first and second magnetic convergence units 10, which are connected to the arcuate racks 9 by means of screws 11 passing through the arcuate slits 8. Thus, the arcuate racks 9 and magnetic convergence units 10 are so fitted to the mounting plate 3 as to slide through arcuate slits 8.
Each of the magnetic convergence units 10 comprises a nonmagnetic rectangular frame 12 having a bottom plate 13 connected to the arcuate rack 9, a dynamic convergence electromagnet including an E-shaped core 14 and dynamic convergence coils 15 wound thereon, and two disc-shaped permanent magnets 16 positioned between the cross-piece of the E-shaped core 14 and frame 12. The magnets 16 are pressed against the cross-piece of the core 14 by compression coil springs 17.
The electron gun assembly of the in-line type color cathode ray tube 2 has three linearly arranged electron guns and consequently the emitted three electron beams 18, 19 and 20 respectively corresponding to red, green and blue colors are also linearly disposed and further separated by magnetic shield plates 21 and 22 so as to prevent interaction between the magnetic fields applied to the electron beams 18 to 20. The beams, in particular the beams 18 and 20, are therefore independently adjustable and their convergence can be controlled by the magnetic convergence units 10, which create dynamic and static fluxes from the free ends of the E-shaped cores 14 for deflecting the beams 18 and 20.
First and second pinion 23 are geared to the arcuate racks 9. Each of the pinions 23 is fixed to one end of a shaft 24 rotatably mounted on a holder 25 formed on the surface of the mounting plate 3. At the other end of the shaft 24 is provided an adjusting wheel 26 for rotating the pinion 23.
The peripheral portion of one surface of the adjusting wheels 26 is provided with a scale 27 for indicating the rotating position of the magnetic convergence units 10 on the mounting plate 3.
In FIGS. 1 to 3, three electron beams 18 to 20 emitted from the linearly arranged three electron guns travel through the n
eck
portion 1 and are deflected in the deflection device 28 mounted on
the outer surface of the funnel portion 29 of the color cathode ray
tube 2 so as to convergently impinge on the fluorescent screen. In the
neck portion 1 the red and blue beams 18 and 20 are magnetically
subjected to deflection by the magnetic convergence units. The
magnetic convergence is achieved using a dynamic convergence flux
obtained by applying an alternating current to the coils 15 and a
static convergence flux obtained by adjusting the arrangement of the
magnetic poles of the two disc-shaped permanent magnets 16. According
to this embodiment, the magnetic convergence is further achieved by
mechanically displacing the magnetic convergence units 10 along the
arcuate slits 8 through rotation of the adjusting wheels 26.In the magnetic convergence device of FIG. 4, the magnetic convergence units 10 are fitted to the mounting plate 3 by screws 30 passing through the slits 8. The diameter of the screw head is larger than the width of the slit 8 and the diameter of the threaded portion of the screw 30 passing through the slit 8 is slightly smaller than the width of the slit 8. Therefore, when all of the screws 30 are loosened, the magnetic convergence units 10 can be easily displaced along the arcuate slits 8 so as to precisely deflect the electron beams 18 and 20. The other elements of the embodiment of FIG. 4 are operated in the same manner as those of FIG. 1 and description thereof is omitted.
Toshiba, "Blackstripe Vertical Stripe Screen Colour Picture Tube", 1973.
Claims:
I claim: 1. In a cathode ray tube including a faceplate and a shadow
mask containing an array of vertically oriented slotted apertures for
restricting electron beams directed therethrough to impinge upon and
excite selected areas of phosphor material on said faceplate, a viewing
screen comprising:
a horizontally repetitive pattern of sets of three vertically oriented
stripes of phosphor material extending vertically across and coating the
inside surface of said faceplate, each stripe within a set being of
different phosphor material so as to emit a different color when excited
by the corresponding one of the three electron beams passing through
the associated aperture in said shadow mask, and
a layer of light absorbing material coating the inside surface of said
faceplate and containing a vertical and horizontal array of vertically
oriented slotted openings, said stripes and openings being juxtaposed so
that said openings define viewable portions of said stripes, each
viewable portion being totally surrounded with light absorbing material,
said openings and stripes being aligned with the apertures in said
shadow mask so that a corresponding one of said three electron beams is
allowed to impinge upon each viewable portion,
the vertical dimension of each opening being greater than the vertical
dimension of that part of said viewable portion excited by the electron
beam impinging thereupon, such that a positive vertical guardband is
provided, and
the horizontal dimension of each opening being less than the horizontal
dimension of the impinging electron beam, such that a negative
horizontal guardband is provided.
2. In a cathode ray tube including a faceplate and a shadow mask
containing an array of vertically oriented slotted apertures for
restricting electron beams directed therethrough to impinge upon and
excite selected areas of phosphor material on said faceplate, a viewing
screen comprising:
a series of vertically oriented stripes of phosphor material extending
across and coating the inside surface of said faceplate, the phosphor
material of horizontally successive stripes differing in a repetitive
pattern so as to emit different colors within each pattern when excited
by electron beams, and
a layer of light absorbing material coating the inside surface of said
faceplate in the form of a matrix comprising vertical stripes of
material interposed between the phosphor stripes and horizontal spans of
material crossing said phosphor stripes,
the vertical stripes and horizontal spans of light absorbing material defining the viewable portions of said phosphor stripes,
the vertical dimension of said horizontal spans being less than or equal
to the vertical region of each phosphor stripe between vertically
adjacent beam landings not excited by said electron beams, such that a
zero to positive vertical guardband is provided for each viewable
portion,
the horizontal dimension of the vertical stripes of light absorbing
material being greater than the horizontal separation between
horizontally adjacent phosphor stripes, such that a negative horizontal
guardband is provided for each viewable portion.
3. In a cathode ray tube including a faceplace and a shadow mask
containing an array of vertically oriented slotted apertures for
restricting electron beams directed therethrough to land upon and excite
selected areas of phosphor materials on said faceplate, a viewing
screen comprising:
a layer of light absorbing material coating the inside surface of said
faceplate and comprising a web containing an array of vertically
oriented slotted openings therein, there being a unique set of three
horizontally spaced openings for each aperture of said shadow mask
aligned to receive the electron beams passing through said aperture, and
a layer of phosphor material coated on the inside surface of said
faceplate within the boundaries of said openings, there being a
different phosphor material for each of the openings of a set so as to
emit a different color when excited by the electron beam impinging
thereupon,
the height of said web between vertically adjacent sets of openings
being less than or equal to the vertical distance between vertically
adjacent beam landings to provide a zero to positive vertical guardband
for each phosphor area,
the width of said web between horizontally adjacent openings being
greater than the horizontal distance between horizontally adjacent beam
landings to provide a negative horizontal guardband for each phosphor
area.
Description:
This invention relates to cathode ray tube screens, and more
particularly to black matrix screens for color television picture tubes
employing slotted aperture masks and a process for fabricating such
screens.
Manufacturers of cathode ray tubes of the color television picture tube
type have recently begun employing aperture masks having slotted
apertures instead of the more conventional circular apertures in order
to achieve greater electron beam transmission through the mask, since an
array of slots in an aperture mask allows the mask geometrically to be
fabricated with more total open area than the same size mask containing
round or circular apertures. The slotted apertures are typically
arranged in vertical columns on the mask, each column being comprised of
a plurality of slotted apertures. Since more electrons can impinge on
the phosphor regions of the screen in a tube of this type than of the
circular aperture, mask type, a brighter picture results. Unlike the
circularly-configured phosphor regions on the screen of a tube employing
an aperture mask having circular apertures, however, the phosphor
regions on the screen of a tube employing an aperture mask having
slotted apertures are formed in a pattern of adjacent vertical stripes,
typically with each stripe running continuously from the top of the
screen to the bottom.
Black matrix tubes have also become widely popular as of late, both in
circular aperture mask tubes and slotted aperture mask tubes. As seen
from the viewing side of the screen of circular aperture mask tubes, the
black matrix material completely surrounds each circular phosphor dot,
serving to improve image contrast by absorbing ambient light that might
otherwise be reflected by the screen. Also as seen from the viewing side
of the screen of slotted aperture mask tubes, each vertical phosphor
stripe is separated from the adjacent vertical phosphor stripe by a
stripe of black matrix material running from the bottom to the top of
the screen.
In fabricating screens for conventional slotted aperture mask tubes of
the black matrix type, a photoresist material coated over the inside
surface of a tube faceplate is exposed in a so-called lighthouse to
actinic radiation in a pattern corresponding to the pattern of matrix
openings ultimately to be formed on the screen. This radiation is
transmitted through the slotted apertures in the mask before impinging
on the photoresist material. The actinic light source used in this
fabrication process is linearly-elongated in a direction parallel to the
columns of slots in the aperture mask in order to permit the black
matrix material to be formed with a pattern of vertically and
horizontally-aligned, vertically-oriented slots extending between the
top and bottom of the screen. The phosphor stripes are thereafter
deposited so that phosphor of a predetermined color emission
characteristic, respectively, is deposited on the faceplate through a
predetermined slot, respectively. Three different phosphor materials are
conventionally deposited in a horizontally-repetitive pattern.
When a screen formed in the aforementioned manner is operated in a color
television picture tube, parts of each of the phosphor stripes are not
excited by the electron beams, since electrons are blocked by the webs
of the mask between vertically-adjacent slots. These parts of the
stripes, therefore, are essentially useless in producing images, since
they provide no illumination on the face of the tube as a result of
direct bombardment by primary electrons. Moreover, the phosphor material
in these regions adds to overall reflectivity of the screen and hence
has a deleterious effect on image contrast. To overcome this problem,
the present invention contemplates substituting black matrix material to
be seen from the viewing side of the screen to avoid reflection from
the parts of the phosphor stripes not excited by the electron beams.
This may be accomplished by using a source of actinic radiation for
producing slotted openings in the black matrix material that is of
shorter length than the linear source of actinic radiation for producing
the phosphor stripes. The resulting increase in area of black matrix
material serves to reduce screen reflectivity and enhance contrast of
the displayed images. Moreover, by controlling vertical size of the mask
webs between vertically-adjacent openings in the black matrix material,
either a positive guardband or negative guardband mode of operation in
the vertical direction may be achieved.
Accordingly, one object of the invention is to provide a new and
improved color television picture tube of the black matrix type
exhibiting reduced screen reflectivity and enhanced image contrast.
Another object is to provide a color television picture tube of the
slotted aperture mask type having a screen, as seen from the viewing
side, formed of a plurality of vertically-oriented linear phosphor
regions completely surrounded by black matrix material.
Another object is to provide a black matrix color television picture
tube of the slotted aperture mask type capable of operating in a
positive or negative guardband mode of operation in the vertical
direction.
A further object is to provide a black matrix color television picture
tube wherein the vertical guardband of the matrix is controlled to
enhance image contrast without reducing image brightness.
Another object is to provide a method of fabricating a color television
picture tube of the black matrix type wherein exposures to different
levels of actinic radiation are employed sequentially in forming the
picture tube screen.
Briefly, in accordance with a preferred embodiment of the invention, a
viewing screen is provided for a cathode ray tube. The tube includes a
faceplate and employs a shadow mask containing an array of
vertically-oriented slotted apertures for restricting electron beams
directed therethrough to impinge on, and excite, selected areas of
phosphor material on the faceplate. The viewing screen comprises a layer
of light-absorbing material coated over the inside surface of the
faceplate, with the layer including a pattern of vertically-elongated
openings therein, and a plurality of vertically-oriented stripes of
phosphor material arranged such that horizontally successive stripes are
comprised of different phosphor materials according to a repeating
pattern. Each of the stripes, respectively, is coated over substantially
the entire area of all the elongated openings situated essentially in
separate vertical alignment, respectively.
In accordance with another preferred embodiment of the invention, a
method of forming on the faceplate of a cathode ray tube a viewing
screen for a high contrast color television picture tube of the slotted
aperture mask, black matrix type is described. The method comprises
forming a first layer of photosensitive material on the inside surface
of the faceplate and exposing the photosensitive material to actinic
radiation through slotted apertures in the mask from a first linear
radiation source of predetermined dimension along its longitudinal axis.
The longitudinal axis of the first source is maintained substantially
parallel to the longitudinal axis of the slotted apertures. The
unexposed regions of the first layer of photosensitive material are then
removed, and a layer of black matrix material is formed atop the first
layer of photosensitive material and the inside surface of the
faceplate. The exposed regions of the first layer of photosensitive
material and the black matrix material coated thereon are next removed,
leaving openings in the black matrix material. A second layer of
photosensitive material is formed atop the black matrix material coated
on the inside surface of the faceplate and atop the exposed portions of
the inside surface of the faceplate. The second layer of photosensitive
material carries a phosphor material either coated thereon or mixed
therein, emitting a characteristic color of light when excited by
electrons. This is followed by exposing the second layer of
photosensitive material to actinic radiation through the slotted
apertures from a second linear radiation source of dimension along its
longitudinal axis exceeding the predetermined dimension, the
longitudinal axis of the second source also being substantially parallel
to the longitudinal axis of the slotted apertures. The unexposed
regions of the second layer of photosensitive material are then removed.
In this fashion, phosphor material is applied over the inside surface
of the faceplate in registry with the openings in the black matrix
layer. If desired, the phosphor material may be applied in the form of
vertical stripes extending between the top and bottom of the screen by
increasing the length of the second radiation source, increasing the
duration of exposure therefrom, or a combination of both.
Toshiba Corporation (Kabushiki-gaisha Tōshiba) is a Japanese
multinational conglomerate corporation, headquartered in Tokyo, Japan.
The company's main business is in infrastructure, consumer products,
electronic devices and components.
Toshiba-made Semiconductors are among the Worldwide Top 20 Semiconductor
Sales Leaders. In 2009, Toshiba was the world's fifth largest personal
computer vendor, after Hewlett-Packard of the U.S., Dell of the U.S.,
Acer of Taiwan, and Lenovo of China.
Toshiba was founded by the merging of two companies in 1939.
One, Tanaka Seisakusho (Tanaka Engineering Works), was Japan's first
manufacturer of telegraph equipment and was established by Hisashige
Tanaka in 1875.[2] . In 1904, its name was changed to Shibaura
Seisakusho (Shibaura Engineering Works). Through the first part of the
20th century Shibaura Engineering Works became a major manufacturer of
heavy electrical machinery as Japan modernized during the Meiji Era and
became a world industrial power.
The second company, Hakunetsusha, was established in 1890 and was
Japan's first producer of incandescent electric lamps. It diversified
into the manufacture of other consumer products and in 1899 was renamed
Tokyo Denki (Tokyo Electric).
The merger in 1939 of Shibaura Seisakusho and Tokyo Denki created a new
company called Tokyo Shibaura Denki (Tokyo Shibaura Electric) (東京芝浦電気).
It was soon nicknamed Toshiba, but it was not until 1978 that the
company was officially renamed Toshiba Corporation.
The group expanded strongly, both by internal growth and by
acquisitions, buying heavy engineering and primary industry firms in the
1940s and 1950s and then spinning off subsidiaries in the 1970s and
beyond. Groups created include Toshiba EMI (1960), Toshiba International
Corporation (1970's) Toshiba Electrical Equipment (1974), Toshiba
Chemical (1974), Toshiba Lighting and Technology (1989), Toshiba America
Information Systems (1989) and Toshiba Carrier Corporation (1999).
Toshiba is responsible for a number of Japanese firsts, including radar
(1942), the TAC digital computer (1954), transistor television and
microwave oven (1959), color video phone (1971), Japanese word processor
(1978), MRI system (1982), laptop personal computer (1986), NAND EEPROM
(1991), DVD (1995), the Libretto sub-notebook personal computer (1996)
and HD DVD (2005).
In 1977, Toshiba merged with the Brazilian company Semp (Sociedade Eletromercantil Paulista), forming Semp Toshiba.
In 1987, Toshiba Machine, a subsidiary of Toshiba, was accused of
illegally selling CNC milling machines used to produce very quiet
submarine propellers to the Soviet Union in violation of the CoCom
agreement, an international embargo on certain countries to COMECON
countries. The Toshiba-Kongsberg scandal involved a subsidiary of
Toshiba and the Norwegian company Kongsberg Vaapenfabrikk. The incident
strained relations between the United States and Japan, and resulted in
the arrest and prosecution of two senior executives, as well as the
imposition of sanctions on the company by both countries.[3] The US had
always relied on the fact that the Soviets had noisy boats, so
technology that would make the USSR's submarines harder to detect
created a significant threat to America's security. Senator John Heinz
of Pennsylvania said "What Toshiba and Kongsberg did was ransom the
security of the United States for $517 million."
In 2001, Toshiba signed a contract with Orion Electric, one of the
world's largest OEM consumer video electronic makers and suppliers, to
manufacture and supply finished consumer TV and video products for
Toshiba to meet the increasing demand for the North American market. The
contract ended in 2008, ending 7 years of OEM production with Orion.
In December 2004, Toshiba quietly announced it would discontinue
manufacturing traditional in-house cathode ray tube (CRT) televisions.
In 2006, Toshiba terminated production of in-house plasma TVs. Toshiba
quickly switched to Orion as the supplier and maker of Toshiba-branded
CRT-based TVs and plasma TVs until 2007. To ensure its future
competitiveness in the flat-panel digital television and display market,
Toshiba has made a considerable investment in a new kind of display
technology called SED.
Toshiba is a diversified manufacturer and marketer of electrical
products, spanning information & communications equipment and
systems, Internet-based solutions and services, electronic components
and materials, power systems, industrial and social infrastructure
systems, and household appliances.
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