JPH0348832Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a beam index type color picture tube.

As shown in FIG. 3, the beam index type color picture tube has three primary color phosphor strips 11, 14, 12 of red, green and blue on the inner surface of a face plate 3, and a non-luminescent material 15 between each phosphor strip. A fluorescent surface is formed by repeatedly coating each layer at the same pitch, and an aluminum metal bag 17 is uniformly deposited on the fluorescent surface.

Furthermore, on the aluminum metal bag, index phosphor strips 16 are arranged at pitches (2/3 pitch of 1 pixel) that have a certain relationship with the pitch of a set of three primary color phosphor strips 10 (hereinafter referred to as 1 pixel). It is being applied. When the phosphor surface is scanned with a single electron beam, the index phosphor is stimulated to emit light. By detecting this light emission, an index signal is obtained, and the accurate scanning position of the single electron beam on the fluorescent surface is detected, and the three primary color signals are switched based on the index signal.

The beam is formed by a red light emitting phosphor strip 11 on the phosphor surface.
(hereinafter simply referred to as the red fluorescing strip 11) to reproduce red color, the beam will expand and emit blue phosphor strips 12 (hereinafter simply referred to as the blue fluorescing strip) for emitting blue light other than red. The phosphor strips 12 and 14 for green light emission (hereinafter simply referred to as the green phosphor strips 14) also overlap, and cause these phosphor strips 12 and 14 to emit light, albeit slightly, to increase the saturation of red color. decreases.

The reason for this is that the spot diameter of the electron beam inevitably increases as the beam amount increases.

In a so-called shadow mask type color picture tube, even if the spot diameter of the electron beam becomes large, the spread of the electron beam on the fluorescent surface is restricted by the shadow mask, so the above-mentioned problem of reduced saturation does not occur.

In the current shadow mask type color television, the color signal sent from the video receiving circuit is demodulated into the three primary color signals of red, green, and blue in the color demodulation circuit, and each primary color signal is used to generate electronic signals for the three primary color phosphor strips. Color reproduction is achieved by density modulating the beam amount and performing additive color mixing of light on the fluorescent surface. In the commonly used color reproduction method, the above color signals are not accurately demodulated and reproduced into three primary color signals, but the demodulation axis is appropriately changed or the amplification factors of each primary color signal are changed mutually. This allows color reproduction to match human vision. As a result, the red primary color signal becomes much larger than the other primary color signals, often reaching approximately twice the size. That is, in actual use of color televisions, the amount of electron beams for the red phosphor stripes is often about twice the amount of electron beams for the green and blue phosphor strips. In such a case, the spot diameter of the electron beam for red becomes larger as described above, but in a shadow mask type color picture tube, the spread of the electron beam on the fluorescent surface is limited by the shadow mask. The problem of color desaturation does not occur.

However, when a beam-index type color picture tube adopts a color reproduction method that emphasizes red as described above, the electron beam directed to the red phosphor strip spreads to the adjacent green and blue phosphor strips. As a result, the color saturation of red is lower than the saturation of other colors.

Beam-index type color picture tubes have the advantage that the efficiency of converting electron beams into light is much higher than shadow-mask type color picture tubes, but as mentioned above, they have the disadvantage of color saturation.

〔the purpose〕

This invention proposes that when a color reproduction method that emphasizes red is adopted in a beam index type color picture tube,
It is an object of the present invention to provide a color picture tube that does not cause a decrease in red color saturation.

〔composition〕

In a beam index type color picture tube, the fluorescent surface is made by repeatedly coating a pixel consisting of two red phosphor stripes and one green and one blue phosphor strip on the face plate. It is characterized by being formed as follows.

[Effect]

When scanning a fluorescent surface with a single electron beam, the green and blue phosphor stripes are irradiated with an amount of electron beam corresponding to each primary color signal, whereas the two red phosphor strips within one pixel are Each photoresist strip is irradiated with an amount of electron beam corresponding to a signal half the size of the red primary color signal. At this time, each of the two red phosphor strips within one pixel emits light with luminance corresponding to the red primary color signal, and as a result, one desired color is reproduced in the entire pixel. Ru. At this time, if the red primary color signal is less than twice the size of the green or blue primary color signals, the spot diameter of the beam that irradiates the red phosphor strip within one pixel will be smaller than that of the green or blue color signal. The spot diameter of the beam on the phosphor strip of That is, the beam for the red phosphor strip also extends to adjacent phosphor strips of other colors, without causing them to emit light.

[Special effects]

Even if a color reproduction method that emphasizes red is used and the red primary color signal is twice as large as the green or blue primary color signal, the color saturation of red is not inferior to that of green or blue, and the shadow mask Color reproduction effects equivalent to that of a standard color picture tube can be obtained.

The present invention will be described in detail below based on the illustrated embodiments.

As shown in FIG. 1, the beam index color picture tube according to the present invention has a fluorescent surface formed by repeatedly coating red, green and blue phosphor strips on the inner surface of the face plate 3. Book red phosphor stripe 1
1, 13 and one green and blue phosphor strip 14,
A total of four primary color phosphor strips 1 consisting of 12 are red,
Blue, red, and green are arranged at equal intervals in that order, and this is one picture element.

Furthermore, a non-luminescent material 15 made of graphite or the like is interposed between adjacent phosphor strips. On the fluorescent surface, an aluminum metal back 17 is uniformly deposited, and on top of that, index phosphor strips 1 are formed on the non-luminescent material 15 at a pitch of 3/4 of the pitch of one picture element.
6 is applied.

FIG. 2 shows an example of the circuit configuration of a beam index type color television using the picture tube 6 according to the present invention. Video receiving circuit (not shown)
The signals from the color signal reproducing circuit 48 are converted into red, green, and blue primary color signals E _R , E _G , and E _B . The red primary color signal E _R is converted to 1/2 the size by an attenuator 49 and becomes a signal 2/E _R. These signals 2/E _R , E _G , and E _B are sequentially switched by gate circuits Q 45 , 46 , and 47 , respectively, and then applied to the grid electrode of the electron gun 32 via an amplifier 50 .

On the inner surface of the face plate 3 of the picture tube 6, there is a fluorescent surface 3 having four stripes of primary color phosphors 1 as one pixel, as described above.
0 is formed, and the electron beam 31 emitted from the electron gun 32 scans the fluorescent surface. At this time, index light 33 is generated by irradiating the index phosphor strip 16. Picture tube 6
A photodetector 41 is disposed in the funnel portion of the photodetector 41, and the photodetector detects the index light 33 described above.

The signal 2e from the photodetector is waveform-shaped into a pulse signal by the index signal processing circuit 42 and becomes the index signal 2a. As shown in FIG. 1b, the index signal 2a has a period of 3/4 pitch of one picture element.

The index signal 2a is branched into first and second signals.
The signal is sent to frequency conversion circuits 43 and 44. The second frequency conversion circuit 44 converts the index signal 2a
is converted to a period of 2/3, and a red pulse signal 2b shown in FIG. 1c is generated. First frequency conversion circuit 43
converts the index signal 2a to a period of 4/3,
A blue pulse signal 2c shown in FIG. 1d and a green pulse signal 2d shown in FIG. 1e are generated. The red, green, and blue pulse signals 2b, 2d, and 2c are input to the red, green, and blue gate circuits 45, 46, and 47, respectively, and control the respective gate circuits.

With the circuit configuration described above, the color picture tube according to the present invention operates as follows.

Four primary color phosphor strips 1 forming one picture element are sequentially irradiated with an electron beam 31. The amount of electron beam for each phosphor strip is determined by the color signal generation circuit 48.
The target color is reproduced as a result of additive color _mixing by the light emitted from _{the four} primary color phosphor strips within one picture element. At this time, the green and blue primary color signals E _G and E _B are amplified by the same amplification factor and applied to the grid electrode of the electron gun 32, whereas the red primary color signal E _R is 1/2 of the amplification factor. It is amplified at a rate of 1 and applied to the grid electrode of the electron gun 32. Therefore, the amount of beam irradiated to each of the two red phosphor strips 11 and 13 within one picture element is approximately 1/2 of the amount of beam corresponding to the red primary color signal E _R.
Thus, the two red phosphor strips 11 and 13 exhibit a predetermined luminance as a set.

If the red primary color signal E _R becomes larger than the green or blue primary color signals E _G , E _B but up to twice as large due to a color reproduction method that emphasizes red, then the red phosphor The amount of electron beam irradiating strip 11 or 13 is less than the amount of beam for phosphor strips 12, 14 of other colors. That is, the spot diameter of the beam for the red phosphor stripe is never larger than the spot diameter of the beam for the phosphor stripes of other colors. Therefore, the beam directed to the red phosphor strip will not strike adjacent phosphor strips of other colors.

In the beam index type color television of this embodiment, even if the red primary color signal reaches twice the strength of the other primary color signals as described above, the red color saturation does not decrease, and the shadow mask type Demonstrates color reproduction performance equivalent to that of television. Furthermore, since the pitch of the index phosphor strips 16 is set to a non-integral multiple of the pitch of one picture element, the occurrence of cross modulation is suppressed.

In this embodiment, the primary color phosphor strips within one picture element are arranged in red, blue, red and green, but the same effect can be obtained with other arrangements. For example, it may be red, red, blue, and green.

However, in this case, it is necessary to construct a circuit that generates primary color pulse signals that match the arrangement of the phosphor strips.

Furthermore, although the pitch of the index phosphor strips is set to 3/4 of the pitch of one picture element, it is of course not limited to this.

[Brief explanation of the drawing]

Fig. 1 is an enlarged sectional view of the fluorescent surface of the beam index type color picture tube according to the present invention and an explanatory diagram of the index signal, and Fig. 2 is a circuit diagram of a color television using the color picture tube of the present invention. , 3rd
The figure is an enlarged sectional view of the fluorescent surface of a conventional beam index type color picture tube. 1... Three primary color phosphor stripes, 3... Face plate, 11, 13... Red phosphor stripes, 12... Blue phosphor stripes, 14... Green phosphor stripes, 16... Index fluorescing Body striations.

Claims (1)

[Claims for Utility Model Registration] A set of fluorescers consisting of two red-emitting phosphor strips, one green-emitting phosphor strip, and one blue-emitting phosphor strip each extending in the vertical scanning direction. By repeatedly applying the body stripes on the face plate in the horizontal scanning direction, a fluorescent surface is formed, and
On the phosphor surface, index phosphor strips extending in the vertical scanning direction are repeatedly formed in the horizontal scanning direction at pitches having a fixed relationship with the repeating pitch of the set of phosphor strips. Color picture tube. The beam index type color picture tube according to claim 1, wherein one set of phosphor strips is arranged in the order of red, blue, red, and green.