JPS629974B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION An object of the present invention is to improve the efficiency of a color cathode ray tube that reproduces color images using a single electron beam.

A typical single electron beam color cathode ray tube uses an electron beam indexing method, in which a secondary electron emitting material or a short afterglow is placed inside the fluorescent screen of the cathode ray tube to detect the position of the scanning electron beam. Many structures have been announced in which a fluorescent material or the like is applied in a certain relationship to the pitch of the fluorescent stripes on the screen. FIG. 1 shows a typical example. In the figure, numeral 1 indicates a fluorescent screen, which is constructed as shown in an enlarged view in FIG. 1b. That is, face plate 1
0, a black stripe 12 is provided between the arrays of phosphor stripes 11 of each color, and stripes 14 of short afterglow phosphor are applied at a certain pitch on the inside of the metal bag 13 corresponding to this position (the figure shows An example is shown in which the pitch matches the pitch of the black stripe 12.) The light emission 7 from the short afterglow phosphor 14 due to the electron beam from the electron gun 2 is received by the phototube 3, and is amplified by the amplification and phase compensation circuit 4. After compensating for the width, shaping, and phase shift, adder circuits 5 and 6 add the color signal and luminance signal, respectively, and apply the obtained signals to the control electrode of the electron gun 2 to modulate the electron beam.
Color reproduction is performed by correctly impacting colored fluorescent stripes.

In this case, it is necessary to focus the electron beam to less than the width of the phosphor stripes in order to reproduce pure colors, and generally black stripes of the same width are often provided between the phosphor stripes.

In a color cathode ray tube with this configuration,
There is a drawback in that it is difficult to form the short afterglow emitter stripes 14 on the back side of the metal bag 13 in terms of manufacturing.

The present invention compensates for these drawbacks, further increases the efficiency of electron beam utilization, and provides a bright and highly stable color cathode ray tube.

An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 2, 21 is an envelope of a cathode ray tube;
2 is an electron gun, 23 is a fluorescent screen, and 24 is a slot plate made of a conductor placed inside the fluorescent screen.

FIG. 3 is an enlarged view showing the relationship between the fluorescent screen 23 and the slot plate 24. The fluorescent screen 23 is constructed by alternately forming black stripes 25 and color stripes 26 on a glass face 29. Slot plate 24 has black stripe 2
Openings 27 are formed at the same pitch as 5. That is, the opening pitch of the slot plate 24 is P _S ,
Letting the triplet pitch of the striped fluorescent surface be P _t , the relationship is P _s 〓P _t /3. This slot plate 24 has an opening with colored striped phosphors 2.
In other words, the non-opening stripe portion of the slot plate is arranged to face the black stripe 25.

Conventional color cathode ray tubes such as a shadow mask type color cathode ray tube and a trinitron type color cathode ray tube are known as devices in which a plate having an opening is disposed inside the fluorescent surface. In these cathode ray tubes, a shadow mask or aperture grill, etc., is installed inside the phosphor screen to have the function of sorting each electron beam into phosphor dots or stripes of each color. The pitch of the openings of the shadow mask or aperture grill is approximately equal to the triplet pitch of the color phosphor, and has a color selective mask effect. On the other hand, the slot plate according to the present invention is based on a completely different principle, in which the 24 opening pitch P _s is equal to the black stripe pitch P _t /3 and does not have a color selection function, as shown in FIG. Furthermore, in post-acceleration type mask focus color CRTs and chromatron type color CRTs, a mask is provided just before the fluorescent surface, but both are masks that have a color selection function like a shadow mask or aperture grill, and the opening pitch is It differs from the slot plate according to the invention by being approximately equal to the color triplet.

Next, the function of the slot plate according to the present invention will be explained. When a slot plate 24 having an opening 27 at the same pitch as the black stripe 25 is provided in an index type single electron beam color cathode ray tube, the slot plate 24 may reach the area where the black stripe 25 is present when the main plate 24 is not present. The wax electron beam is absorbed by the slot plate 24 and any electrons passing through the aperture 27 impinge on the color phosphor stripe 26. Therefore, by limiting the width of the electron beam to be smaller than the width of the phosphor stripe 26, each color can be emitted separately. Since the electrons absorbed by the slot plate 24 have position information corresponding to the slot pitch _Ps , it is possible to control the color signal using this as an index signal. In other words, this slot plate 24 is not a mask effect but an index detection means, and its pitch P _s is different from that of any conventional master.

FIG. 4 shows a case in which the slot pitch P _R at the starting end 281 of the slot plate 28 for horizontal scanning of the electron beam is different from the slot pitch P _S at the portion 282 facing the effective screen, that is, the color phosphor stripe 26. Triplet Pitch P _t
This is an example in which the values are the same. If this slot plate 28 is used, a pulse generated at the slot 281 at the start of horizontal scanning of the electron beam can reset the counter and ensure correct color reproduction during scanning. Details will be described later.

FIG. 5 is an example of a circuit for driving a cathode ray tube according to the present invention. In the figure, 60 is a color cathode ray tube according to the present invention, 61 is the same slot plate as the slot plate 28 shown in FIG. 4, and 62 is a resistor whose one end is grounded and the other end is connected to the slot plate 61. 63 and 64 are tuning circuits, 65 and 66 are limiter circuits, 67 is a 1/3 counter circuit, 68 is a reset pulse generation circuit, 69 is a phase calibration circuit, and 7
0 and 71 are mixer circuits, 72 is an adder circuit, and 73 is an electron gun.

When the electron beam 74 scans the face, the electron beam passes through the opening in the slot plate 61 and impacts the colored fluorescent stripes, causing them to emit light. on the other hand,
The electron beam that flows into the slot plate 61 without passing through the opening of the slot plate 61 passes through the resistor 62.
As a result, a pulse voltage having a frequency corresponding to the pitch of the slot plate 61 is generated at both ends of the resistor 62.

At the start of scanning of the electron beam, a pulse with a frequency corresponding to the slot pitch P _R is generated, and this pulse is selectively extracted by the tuning circuit 64, waveform-shaped by the limiter 66, drives the reset pulse generation circuit, and controls the 1/3 counter. Reset. On the other hand, a pulse with a frequency corresponding to the slot pitch P _s of the plate portion corresponding to the color phosphor stripe is selectively extracted by a tuning circuit 63, waveform-shaped by a limiter 65, counted down by a 1/3 counter, and then pulsed by a phase calibration circuit 69. The index pulse is then phase-compensated to produce an index pulse corresponding to any one color of the colored phosphor stripes. This pulse is mixed with a burst signal and a chroma signal in mixer circuits 70 and 71, respectively, and further added with a luminance signal in an adder circuit 72, which is applied to a control electrode of an electron gun 73. This allows the electron beam to illuminate the correct phosphor stripe.

In the above explanation, we have explained an example in which the frequency of the index signal is ₃₀ when the repetition frequency of the phosphor triplet is _0. However, if every other current extraction strip of the slot plate is insulated, the frequency can be reduced to _1.50. An index signal is obtained, and color reproduction can be performed using a conventionally well-known index processing circuit.

FIG. 6 shows an embodiment in which the index signal from the slot plate is extracted optically. In the figure, 76 is a glass face, 77 is a colored phosphor stripe, 78 is a black stripe, 79 is a slot plate, and 80 is a short afterglow ultraviolet phosphor. In this embodiment, ultraviolet light is generated when the short afterglow ultraviolet phosphor 80 is irradiated with the electron beam.
This ultraviolet pulse can be used as an index signal. In order to detect such an optical index signal, a photoelectric conversion element such as a photomultiplier may be provided on the tube wall, and its output may be applied to tuning circuits 63 and 64 shown in FIG. When the index signal is extracted optically in this manner, the signal-to-noise ratio during detection is significantly improved.

In this embodiment as well, short afterglow ultraviolet phosphors can be formed one by one on the slot plate.

Further, instead of the short afterglow ultraviolet phosphor, other short afterglow phosphors or secondary electron emitting materials may be formed. If a secondary electron emitting material is used, a secondary electron collector may be provided inside the tube, and the resulting signal may be taken out of the tube.

As shown in Fig. 5, when a positive voltage 75 is applied between the slot plate and the phosphor surface to form a focusing lens field that focuses the electron beam just in front of the screen surface, the final spot diameter of the electron beam is reduced. and improve the utilization rate of electron beams.
You can get a bright and sharp screen.

As described above, the present invention provides an electron beam index color cathode ray tube having a phosphor surface in which color phosphor stripes and black stripes are arranged alternately, and a slot plate having a stripe pitch equal to the black stripe pitch. This provides a color cathode ray tube that is arranged on the inside of the phosphor surface so that the opening faces the color phosphor stripe, and there is no manufacturing difficulty in forming the index stripe directly on the back side of the metal back surface. Furthermore, by applying a positive voltage within the slot plate and the phosphor surface, the spot diameter of the electron beam can be reduced and the utilization efficiency can be improved.

[Brief explanation of the drawing]

FIG. 1a is an explanatory diagram of the operation of a conventional electron beam indexing color cathode ray tube, FIG. 1b is an enlarged view of the same essential parts, and FIG. 3 is an enlarged view of the vicinity of the screen of the electron beam indexing color cathode ray tube according to the present invention, FIG. 4 is an enlarged view of the vicinity of the screen of another embodiment of the electron beam indexing color cathode ray tube of the present invention, and FIG. This figure is a signal processing block diagram when the color cathode ray tube according to the embodiment of FIG. 4 is used, and FIG. 6 is a sectional view of a main part of still another embodiment of the beam index type color cathode ray tube according to the present invention. 23... Fluorescent screen, 24, 28, 6
1,79...Slot plate, 25,78...
Black stripe, 26,77...Colored phosphor stripe, 27...Slot plate opening, 29,7
6... Glass face, 80... Short afterglow phosphor, 63, 64... Tuning circuit, 65, 66... Limiter, 67... 1/3 counter, 68... Reset pulse, 69... Phase Calibration circuit, 70, 71...
...mixing circuit, 72...addition circuit.

Claims (1)

[Scope of Claims] 1. A slot plate having a phosphor surface in which colored phosphor stripes and black stripes are arranged alternately, and having stripes of a pitch equal to the pitch of the black stripes, the openings of the slots are colored. A color cathode ray tube, characterized in that the tube is disposed inside the phosphor surface so as to face the phosphor stripes. 2. A color cathode ray tube according to claim 1, wherein the slot plate is a conductor. 3. A color cathode ray tube according to claim 1, wherein the stripe of the slot plate is entirely or partially coated with a short afterglow phosphor or a secondary electron emitter. 4. A color cathode ray tube according to any one of claims 1 to 3, characterized in that a voltage is applied between the slot plate and the fluorescent surface so that the fluorescent surface becomes positive. . 5. Claim 1, characterized in that the slot pitch at the starting end of the electron beam horizontal scanning of the slot plate is different from the slot pitch at the effective screen section.
The color cathode ray tube according to any one of items 1 to 4.