JP3005991B2 - Television receiver - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a television receiver suitable for use in HDTV (High Definition Television).

[Summary of the Invention]

The present invention is a cathode ray tube suitable for use in an HDTV, which irradiates an electron beam onto a phosphor surface through a hole formed in a color selection electron beam shielding plate to project an image, and scans the electron beam. Deflecting means, a fluorescent material for beam position information detection applied to the back of the electron beam shielding plate for color selection, and a light from the fluorescent material for beam position information detection to detect the position of the electron beam. A cathode ray tube having beam position information detecting means for detecting, and a scanning speed when a beam irradiates a phosphor surface through a hole of a color selection electron beam shielding plate based on a detection output signal of the beam position information detecting means. Deflection control means for controlling the deflection means so that the beam illuminates the electron beam shielding part of the color selection electron beam shielding plate, and a detection output signal of the beam position information detection means. And a sample-and-hold means for holding the level of the video signal supplied to the cathode ray tube at the timing when the electron beam irradiates the phosphor surface through the hole of the color-selecting electron beam shielding plate based on the signal. Thus, a high-accuracy television receiver is obtained.

[Conventional technology]

In recent years, HDTV has been widely developed, and direct-view and projection cathode-ray tubes (CRTs) have been developed as displays usable for HDTV. Fig. 7 shows such an electron gun structure for HDTV. The basic structure is the same as that of a conventional CRT, but the screen size is 30 inches or more, the resolution is 1000 TV horizontal or more, and the brightness is Is desired to have a performance of 150 cd / m ² or more. FIG. 7 shows an electron gun structure of a CRT using an aperture grill. In FIG. 7, G ₁ is a first grid to modulate the beam emitting source and a beam, the electron gun R, G, B are in-line arranged. G ₂ and G ₃ are pre-focus electrodes for the second and third grids, G ₄ are focus cylindrical electrodes for the fourth grid, and third and fifth grids.
A high voltage is supplied to G ₃ , G ₅ , and the third to fifth grids G ₃ , G 5
G ₄ and G ₅ form a unipotential lens. Fifth
Electrode CE is disposed in front of the grid G ₅ is a convergence electrode for electrostatic concentration deflected, the electron gun R, G, electron beams emitted from the B is focused by the fourth grid G _4, at convergence electrode CE The light is concentrated and deflected and converged through an aperture AG. The aperture grill AG is formed by etching a metal plate to form a slit hole (4) in the vertical direction by etching, and is radiated from the electron guns R, G, and B passing through the slit hole (4) of the aperture grill AG. R, G, B
The beam for the phosphor is the phosphor surface R of the phosphor PC formed on the inner surface of the CRT.
₁ , G ₁ , and B ₁ are irradiated to emit red, green, and blue primary colors. In the HDTV, as described above, the pitch of the aperture grill AG is made smaller than that of the current NTSC system in order to make the resolution 1000 TV lines or more. The gap between small since Apachaguriru electron beam passed through the AG (1) is Baranara not have to as hit exactly the example, red phosphor surface R ₁ of the phosphor PC corresponding as shown in Figure 8. FIG. 9 is not the aperture grille, but the pitch of the aperture (2) of the shadow mask of the current television (FIG. 9A) and the pitch of the television shadow mask aperture (3) of the HDTV (FIG. 9B).
In the HDTV, for example, in a 40-inch CRT, the pitch is about 450 μm and the hole diameter of the shadow mask is 220 μm.
m is selected. As described above, the aperture grill gap or the aperture pitch of the shadow mask becomes smaller, and the phosphor screen such as the stripes or dots of the phosphor PC becomes smaller, so that the resolution increases.
Be taken only about 1/3 of the home television brightness of the system, Figure 10 is HDTV and the current television took white peak luminance (cd / m ²⁾ a CRT screen size on the horizontal axis to vertical axis This shows that the brightness of the direct-view CRT is about 1/3 that of the current television, and that the projection CRT is about half the brightness. Figure 8 electron beam (1) is slit (4) so is smaller strike the phosphor CRT for example phosphor surface R ₁ time is reduced when passing through the stripe-shaped slit (4), as a whole Will decrease in brightness. FIG. 11 shows a linear graph (7) in which the horizontal axis represents time and the vertical axis represents the position of the electron beam. This electron beam (1) emits light by striking the phosphor surface of the phosphor PC. The section (6) is extremely short and the other section (5) does not contribute to light emission at all, but this section (5) is extremely long, and more than 70% of the electron beam is wasted. For example, the transmittance of the electron beam is about 20% in the shadow mask type, and is about 27% in the aperture grill type.

[Problems to be solved by the invention]

As mentioned above, it is a big challenge to improve the brightness of the screen in the CRT for HDTV. Such brightness, that is, brightness B of a general television is expressed by the following equation (1).

B∝V ・ I ・ T (1) where V is high voltage, I is beam current, and T is phosphor PC
Is the time during which the electron beam (1) is shining.

That is, in order to improve the brightness B, the characteristics of each parameter of the above equation (1) may be improved. For this purpose, specifically, an electron gun having a high current density, a projection tube of an electromagnetic focusing type, and a focus technique in which the focus is not deteriorated even when a large current is applied are being studied. However, in the case of a high current density electron gun (cathode) or the like, there is a problem that the brightness improvement rate is about several percent. The present invention focuses on the time T in the parameters of the first equation.

The television receiver of the present invention has been made in view of the above-described problems, and its purpose is to achieve a resolution of 1000 TV.
An object of the present invention is to provide a television receiver capable of greatly increasing the brightness (luminance) of the television receiver.

[Means for solving the problem]

The present invention relates to a cathode ray tube (16) for projecting an image by irradiating an electron beam (1) onto a phosphor surface through a hole formed in a color selection electron beam shielding plate AG to project an image. Deflecting means (15) for scanning light, a fluorescent material (27) for detecting beam position information applied to the back surface of the electron beam shielding plate (16) for color selection, and a fluorescent material (27) for detecting beam position information ( 27) a cathode ray tube (16) having beam position information detecting means (28) for detecting the position of an electron beam by detecting light from the light source, and based on a detection output signal of the beam position information detecting means (28). The scanning speed when the electron beam (1) irradiates the phosphor surfaces R, G, and B through the holes of the color-selecting electron beam shielding plate AG is set to the electron beam shielding of the color-selecting electron beam shielding plate AG. Deflection means (15) so as to be slower than the scanning speed when irradiating the part. The electron beam (1) passes through the holes of the color-selecting electron beam shielding plate AG based on the deflection output means (24) for controlling the polarization and the detection output signal of the beam position information detecting means (28). A television receiver characterized by having sample holding means (22) for holding the level of the video signal supplied to the cathode ray tube (16) at the timing of irradiating B.

[Action]

According to the television receiver of the present invention, the electron beam of the CRT is deflected to control the electron beam (1) so as to extend the time that the electron beam (1) hits the phosphor surface, and to sample and hold the video signal during that period. The brightness of the CRT for HDTV can be greatly improved without reducing the resolution.

〔Example〕

Hereinafter, the television receiver of the present invention will be described with reference to FIGS.
The figure will be described.

FIG. 1 is a system diagram showing an embodiment of the television receiver of the present invention. Before explaining this system diagram, the HDTV CRT of the present invention shown in FIGS. 2 to 4 will be described in detail. I do. FIG. 2 is a conceptual diagram for explaining the electrode configuration of the CRT used in the television receiver of the present invention and a beam position sensor. Is omitted. In FIG. 2, the fourth grid G ₄ divides the cylindrical electrode into two parts as shown in the perspective view of FIG.
The fourth grid electrode G _4a and the second fourth grid electrode G _4b are used. FIG. _{4 is} an enlarged perspective view of the fourth grid G4 of the CRT shown in the enlarged section A of FIG. 3, in which the fourth grid as the focus electrode is divided on the YZ plane of the screen of the CRT (16). As will be described later, electrostatic deflection is performed by applying a control voltage for electron beam control to the first and second fourth grid electrodes G _4a and G _4b . That is, the first and second
The fourth grid electrode G _4a, the electron beam passing between G _4b when the potential of the first fourth grid electrode G _4a is greater than the potential of the second fourth grid electrode G4 _4b of FIG. 3 CRT ( 16)
The screen is bent by receiving a force in the right direction of the screen, and further horizontal and vertical deflection scanning is performed by the main deflection scanning composed of the deflection yoke (15) shown in FIG.

Passing through the first and second fourth grid electrodes G _4a and G _4b ,
The electron beam passing through the fifth grid G ₅ and the convergence electrode CE is focused through the Apachaguriru AG, this embodiment of the CRT (16) in the upper end of the Apachaguriru AG, the back side of the C
Apply a fluorescent material (27) with almost no afterglow characteristics to a position that cannot be seen from the RT screen surface. Also, a sensor (2) for detecting the aperture grill position facing the fluorescent material application surface.
Before scanning the first scanning line with 8), the fluorescent material application surface is scanned, light from the fluorescent material is detected by the sensor (28), and the position data of the aperture grill AG is extracted. It is configured as follows.

Hereinafter, FIG. 1 will be described. T ₁ in the figure HDTV signal is input at an input terminal. The HDTV composite video signal is supplied to a video signal processing circuit (10) and a synchronization separation circuit (17).
Video signal processing is performed by a video signal processing circuit (10), and the video signal is digitized by an analog-to-digital converter (hereinafter referred to as A / D) (11) and digitized by an A / D (11). The data is stored in the image memory (12), and the stored data read from the image memory (12) is added to the addition circuit (1).
After adding the video data of the white signal in 3),
(Hereinafter referred to as D / A) to analog conversion circuit (14) is an analog of supplied to the first electron gun grid G ₁ of the CRT in.
After the video signal is synchronized and separated by the sync separation circuit (17),
The vertical and horizontal synchronization signals V and H are generated and supplied to a vertical deflection circuit (18) and a horizontal deflection circuit (19). These vertical and horizontal synchronization signals V and H are located near the neck and funnel of the CRT (16). The main deflection yoke (15) arranged in the above-mentioned manner drives the vertical deflection coil VDC and the horizontal deflection coil HDC to deflect the electron beam in the horizontal and vertical directions.

The vertical and horizontal synchronizing signals V and H generated by synchronizing and separating in the synchronizing separation circuit (17) are supplied to a position detection data memory (21) in a control circuit (20), and further used for detecting the position of the aperture grill AG. The position detection output from the sensor (28) is supplied to the position detection data memory (21) via the amplifier (26). Before scanning the first horizontal scanning line, the surface of the aperture grill AG coated with the fluorescent material (27) is scanned with an electron beam, and the light emitted from the fluorescent material (27) is detected by the sensor (28). A position detection output is obtained. During this scanning, the fluorescent material (27) is illuminated with white signal video data described later, and this light is made incident on the sensor. In this way, the position information data of the aperture grill AG is output as serial timing data, stored in the position detection data memory (21), and the position is detected when the first horizontal scanning line that allows only the image to be viewed from the front of the CRT screen is obtained. electrode G for use in an electrostatic deflection electron beam (1) on the basis of the distance data of Apachaguriru AG timing data stored in the data memory (21) is always above as striking the phosphor surface R _1, G _1, B _1, etc. Control _4a and G _4b . For this purpose, a reference clock from a reference signal generator (23) having a crystal oscillator X-Tal is also supplied to the position detection data memory (21), and the reference clock interval is read out from the aperture grille read from the position detection data memory (21). The corresponding data is supplied to the hold pulse generation circuit (22). Outputs video data hold pulse for holding the video signal at a predetermined timing described later video data to the hold pulse generator circuit (22) in first output terminal T _2, the clock pulses for the video data hold A / D (11 ), Image memory (12), D / A (14)
And, for example, the read address of the image memory (12) is stopped for a hold time described later. The position of the electron beam (1) is changed stepwise from the hold pulse generation circuit (22) as shown in FIG.
Phosphor surface R ₁ in, G _1, timing pulse for B ₁ exactly electron beam (1) is controlled so strikes is output to the output terminal T _4. FIG. 5 shows a linear graph (7) in which the horizontal axis represents time and the vertical axis represents the beam position as in FIG. 11, and the time corresponding to the section is actually the time when the electron beam (1) is actually emitted from the phosphor surface R _1. , G ₁ ,
It represents the time that hit the B _1. The beam position is changed in a step (30) so that the electron beam (1) hits the phosphor surface only during the time corresponding to this section. The control voltage at the timing of output timing pulses to the output terminal T ₄ for is supplied to one input terminal of G ₄ grid driving amplifier (24). G ₄ are the other input terminal of the grid driving amplifier (24) is a reference voltage from the reference voltage source (25) is supplied, the output terminal of the driving amplifier (24) sum and difference of the input control voltage and the reference voltage output (+) And (-) are output and supplied to the second fourth grid electrode G _{4b along} with the first divided fourth grid electrode G _4a in the CRT (16) described above, and the electron beam ( 1) is electrostatically deflected. Control circuit (2
The output terminal T ₃ 0) For example, after the vertical synchronizing signal is outputted only white signal video data a predetermined period, are supplied to an adder circuit which is arranged to a video signal system path (13). According to the present example, the electron beam (1) in the X-axis direction in FIG. 3 is applied to the aperture grill AG in accordance with the potential of the control electrode supplied to the first and second fourth grid electrodes G _4a and G _4b . It is controlled so as to be brought to the position of the stripe-shaped slit hole (4), and the main deflection yoke (15) performs vertical and horizontal scanning.

6A and 6B are waveform explanatory diagrams showing a sample-and-hold state of the video signal of the present example. In FIGS. 6A and 6B, (33) indicates a synchronization signal, (31) indicates a video signal, and (32) in FIG. 6A indicates a CRT.
(16) represents the time during which the electron beam is applied to the phosphor surfaces R ₁ , G ₁ , B _1, etc. of the phosphor PC. If the read address of the image memory (12) is stopped at this time, the sample signal is sampled and held (34) at the level of the video signal at this time as shown in FIG. 6B. CR at this sampled and held level
What is necessary is just to drive the cathode of T (16). With this configuration, the white and black levels of the video signal are clarified by the sample and hold circuit in accordance with the video signal value, and the image quality can be improved.

Since the present invention is configured and operated as described above, it is possible to greatly increase the luminance while maintaining the resolution of the HDTV with high accuracy, and to provide a television receiver having substantially the same brightness as the current television. Can be obtained.

Although the present invention has been described with reference to a CRT having an aperture grille, the present invention can be similarly applied to a shadow mask type. It is clear that the configuration of the electron gun is not limited to the unipotential type but may be a bipotential type as long as it can deflect the focus potential electrostatically or electromagnetically. Of course, it can be variously changed.

〔The invention's effect〕

According to the television receiver of the present invention, when deflecting the electron beam, when the electron beam hits the phosphor surface of the CRT, it scans at a low speed or at a low speed, and the electron beam hits other than the aperture of the aperture grill or the shadow mask. At the time, scanning is performed at a high speed, so that the brightness of the CRT can be greatly increased.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of a television receiver of the present invention, FIG. 2 is an explanatory diagram of an electron beam position sensor of a CRT used in the present invention, FIG. 4 Figure is an enlarged perspective view of a G ₄ grid, Figure 5 is an electron beam scanning method illustration of the present invention, FIG. 6 is a sample and hold waveform, FIG. 7 is electrode configuration diagram of a conventional CRT, FIG. 8 is Schematic diagram of the electron beam near the aperture grill, Fig. 9 shows the current TV
FIG. 10 is a comparison diagram of the aperture of the shadow mask of the HDTV, FIG. 10 is a comparison diagram of the brightness of the current TV and that of the HDTV, and FIG. 11 is an explanatory diagram of a state in which the conventional phosphor is irradiated with an electron beam. G ₄ is the fourth grid, G _4a is the first fourth grid electrode, G _4b
Is a second fourth grid electrode, (10) is a video signal processing circuit, (11) is an A / D, (12) is an image memory, (13) is an addition circuit, (14) is a D / A, (20) ) Is the control circuit, (2
1) is a position detection data memory, and (22) is a hold pulse generation circuit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 3/30 H04N 9/18 H04N 9/24

Claims (1)

(57) [Claims] A cathode ray tube for projecting an image by irradiating an electron beam onto a phosphor surface through a hole formed in an electron beam shielding plate for color selection, and deflecting means for scanning the electron beam. A fluorescent material for detecting beam position information applied to the back surface of the electron beam shielding plate for color selection, and a beam position for detecting a position of the electron beam by detecting light from the fluorescent material for detecting beam position information. A cathode ray tube having information detection means, and a scanning speed when the electron beam irradiates the phosphor surface through a hole of the color selection electron beam shielding plate based on a detection output signal of the beam position information detection means. Deflection control means for controlling the deflection means so that the beam illuminates the electron beam shielding portion of the color-selecting electron beam shielding plate at a speed lower than the scanning speed; A sample-and-hold means for holding a level of a video signal supplied to the cathode ray tube at a timing at which an electron beam irradiates the phosphor surface through a hole of the color-selecting electron beam shielding plate based on a detection output signal of the detection; A television receiver comprising: