JPS6188674A - Picture display device - Google Patents

Abstract

PURPOSE:To input directly a digital external signal from a personal computer by providing a means selecting and inputting the digital external input signal corresponding to 1-bit of an output of an A/D converter. CONSTITUTION:A primary color video signal R is a digital signal via an A/D converter 43 and inputted to a latch group via an output line 44 and a tri-state buffer 48. On the other hand, the digital external signal REXT from a personal computer is inputted to the said latch group via a white balance setting switch 50 and a tri-state buffer 49. The tri-state buffers 48, 49 are controlled by an input switching signal SW1. The input signal bit is selected by a white balance set switch 50 to set an optional bit in response to the digital input thereby eliminating an unnecessary bit.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention generates an electron beam for each division when a screen on a screen is vertically divided into a plurality of divisions, and generates an electron beam for each division. The present invention relates to an apparatus for displaying a plurality of lines by vertically deflecting a beam to display a television image as a whole.

Conventional configuration and its problems Conventionally, cathode ray tubes have been mainly used as display elements for displaying color television images, but conventional cathode ray tubes have a large screen size.

It was impossible to create a thin television receiver with such a long depth. Furthermore, as flat display elements, EL display elements, plasma display devices, liquid crystal display elements, etc. have recently been developed.

All of them are insufficient in terms of performance such as brightness, contrast, and color display, and have not yet been put into practical use.

Therefore, the present applicant proposed a new display device in Japanese Patent Application No. 56-20618 (Japanese Unexamined Patent Publication No. 57-135590) to achieve a flat display device using electron beams.

This method generates an electron beam for each section when both sides of the screen are vertically divided into multiple sections, and displays multiple lines by deflecting each electron beam vertically for each section. However, it displays a television image as a whole.

First, a basic configuration example of the image display element used here will be explained with reference to FIG. This display element consists of, in order from the back to the front, a back electrode (1), a line cathode (2) as a beam source, a vertical focusing electrode (3), and a vertical deflection electrode (
4), beam current control electrode (5).

A horizontal focusing electrode (6), a horizontal deflection electrode (7), a beam acceleration electrode (8), and a screen plate (9) are arranged and configured, and these are made into a vacuum of a flat glass bulb (not shown). An auxiliary electrode (3') as a second vertical focusing electrode or a pre-vertical focusing electrode is arranged between the vertical deflection electrode (4) and the beam current control electrode (5) as necessary. Sometimes I do.

A line cathode (2) serving as a beam source is stretched horizontally so as to generate an electron beam distributed linearly in the horizontal direction, and a plurality of line cathodes (2) are arranged vertically at appropriate intervals. Books (only four books (2a) to (2d) are shown in the figure) are provided. In this conventional example, it is assumed that 15 pieces are provided. Let them be (2a) to (2o). These wire cathodes (2) are constructed by coating the surface of a tungsten wire with a diameter of 10 to 20 μΦ with an oxide cathode material for thermionic emission. These line cathodes (2a) to (20) are heated so as to generate a thermionic beam by passing an electric current through them, and as described later, the line cathodes (2a) to (20) are heated sequentially for a certain period of time. It is controlled to emit an electron beam at a time. The back electrode (1) suppresses the generation of electron beams from line cathodes other than the line cathode controlled to emit the child beam for a fixed period of time, and forwards the generated electron beams. It acts to push out only in one direction. This back electrode (1) may be formed by a coating of electrically conductive material applied to the inner surface of the rear wall of the glass bulb. Moreover, a planar electron beam emitting cathode may be used instead of the back electrode (1) and the linear cathode (2).

The vertical focusing electrode (3) is a conductive plate (11) having a horizontally long slit (10) facing each of the line cathodes (2a) to (20), and collects the electron beam emitted from the line cathode (2). taken out through the slit (10),
and vertically focused. 1 horizontal line (3
68 picture elements) of electron beams are taken out at the same time. In the diagram,
Of these, only one section in the horizontal direction is shown.

The slits (10) may be provided with crosspieces at appropriate intervals in the middle, or may be a row of through holes provided in large number at small intervals in the horizontal direction (intervals that are almost touching). It may be configured substantially as a slit. When the auxiliary electrode (3')' is arranged as a second vertical focusing electrode, its shape is similar to the vertical focusing electrode (3) described above, and when it is arranged as a front horizontal focusing electrode, it has the same structure as described below. The structure is similar to that of the horizontal focusing electrode (6).

A plurality of vertical deflection electrodes (4) are arranged horizontally at intermediate positions between the slits (10), and conductors (13) ( 13'). And opposing conductors (13) (13')
A vertical deflection voltage is applied between them to deflect the electron beam in the vertical direction. In this conventional example, a pair of conductors (13)
(13') deflects the electron beam from one line cathode (2) vertically to a position corresponding to 16 lines. The 16 vertical deflection electrodes (4) constitute 15 conductor pairs corresponding to each of the 15 line cathodes (2), so that 240 horizontal lines are drawn on the screen (9). Deflect the electron beam to

Next, the control electrodes (5) are composed of conductive plates (15) each having a long slit (14) in the vertical direction, and a plurality of control electrodes (5) are arranged in parallel in the horizontal direction at a predetermined interval.

In this conventional example, 184 conductive plates for control electrodes (15-
1) to (15-n) are provided. (Only 9 lines are shown in the figure). Each of the control electrodes (5) divides the electron beam horizontally into two picture elements and extracts it.
And the amount of passage thereof is controlled according to the video signal for displaying each picture element. Therefore, if 184 conductive plates (1, 5-1) to (15-n) for the control electrode (5) are provided, 368 pixels can be displayed per horizontal line.

In addition, in order to display images in color, each picture element is R, G.
, B, and each control electrode (
5), R2O and B video signals for two picture elements are sequentially added. In addition, conductive plates (1
5-1) to (15-n) each has one line worth of
84 pairs of video signals (2 picture elements per pair) are applied simultaneously, and one line of video signals is displayed at once.

The horizontal loading electrode (6) is connected to the slit (14) of the control electrode (5).
) is composed of a conductive plate (17) having a plurality of vertically long slits (16) facing each other, and the electron beam for each pixel divided horizontally is transmitted horizontally. Focus into a narrow beam of electrons.

The horizontal deflection electrode (7) is composed of a plurality of conductive plates (18) (18') arranged vertically on both sides of the slit (16) marked -11. ) (18') is applied with six levels of horizontal deflection voltage to deflect the electron beam for each picture element in the horizontal direction.

Each phosphor of B is sequentially irradiated to emit light. In this conventional example, the deflection range is a width of two picture elements for each electron beam.

The accelerating electrode (8) is composed of a plurality of conductive plates (19) installed horizontally in the same position as the vertical deflection electrode (4), and it directs the electron beam to the screen (9) with sufficient energy. Accelerate to cause a collision.

The screen (9) is constructed by applying a phosphor (20) that emits light when irradiated with an electron beam to the back surface of a glass plate (21), and adding a metal back layer (not shown). The phosphor (20) has two phosphors of three colors R2O and B for one slit (14) of the control electrode (5), that is, for each one electron beam divided in the horizontal direction. They are provided in pairs and are applied in vertical stripes. In FIG. 1, the broken lines drawn on the screen (9) indicate vertical divisions displayed corresponding to the plurality of line cathodes (2), and the two-dot chain lines indicate the divisions in the vertical direction that are displayed corresponding to the plurality of line cathodes (2). ) shows the horizontal divisions displayed corresponding to each of them. As shown in the enlarged view in Figure 2, one section partitioned by these two has R, G, and B phosphors (20) for two pixels in the horizontal direction, and 16 lines in the vertical direction. It has a width of 30 minutes. The size of one section is, for example, IIm in the horizontal direction and 9 in the vertical direction.
It is mn.

=8- It should be noted that in FIG. 1, the length in the horizontal direction is greatly expanded relative to the length in the vertical direction for the sake of clarity.

Moreover, in this conventional example, one control electrode (5), that is, one
For the electron beam of the book, R, G, B phosphors (20)
is provided for only one pair for two picture elements, but of course, one
A picture element or three or more picture elements may be provided, and in that case, R, G, and B video signals for one picture element or three or more picture elements are sequentially applied to the control electrode (5), and synchronized with the R, G, and B video signals for one picture element or three or more picture elements. horizontal deflection.

Next, the basic configuration and waveforms of each part of a drive circuit for displaying television images on this display element will be explained with reference to FIG. First, a driving portion for irradiating the screen (9) with an electron beam to emit raster light will be explained.

The power supply circuit (22) is a circuit for applying a predetermined bias voltage (operating voltage) to each electrode of the display element.
-■□ for 1), ■3 for the vertical focusing electrode (3), v3' for the auxiliary electrode (3'), V for the horizontal focusing electrode (6), v, l for the accelerating electrode (8). , a DC voltage of v9 is applied to the screen (9).

Next, a composite video signal of a television signal is applied to the input terminal (23), and a vertical synchronizing signal (2) and a horizontal synchronizing signal (H) are separated and extracted in a synchronization separation circuit (24).

The vertical deflection drive circuit (40) includes a vertical deflection counter (2
5), a memory for vertical deflection signal storage (27), and a digital-to-analog converter (39) (hereinafter referred to as a DA converter). As input pulses to the vertical deflection drive circuit (40), a vertical synchronizing signal V and a horizontal synchronizing signal H shown in FIG. 4 are used. Vertical deflection counter (25) (
8 bits) are reset by the vertical synchronization signal V and count the horizontal synchronization signal H.

This vertical deflection counter (25) counts the effective scanning period (in this case, a period of 240H) excluding the vertical blanking period of the vertical period, and this count output is supplied to the address of the memory (27). be done. The memory (27) outputs vertical deflection signal data (10 bits in this case) corresponding to each address, and the D-A converter (39) converts the data to υ shown in FIG. 4 (FIG. 3(b) D). , υ′ is converted into a vertical deflection signal. This circuit has memory addresses for storing vertical deflection signals corresponding to each line for 240H, and by storing regular data in the memory every 16H, it is possible to obtain 16 levels of vertical deflection signals. can.

On the other hand, the line cathode drive circuit (26) uses the vertical synchronization signal V and the output of the vertical deflection counter (25) to create line cathode drive pulses a to 0. FIG. 5(a) shows the vertical synchronization signal V,
The relationship between the horizontal synchronizing signal H and the lower 5 bits of the vertical deflection counter (25) is shown. FIG. 5(b) shows a method of creating line cathode drive pulses a' to 0' every 161 cm using each of these signals. In FIG. 5, LSB indicates the lowest bit, and (LSB+1) means the bit one higher than the LSB.

The first line cathode drive pulse a'' can be created using an R-S flip-flop or the like using the vertical synchronizing signal V and the output (LSB+4) of the vertical deflection converter (25).
The line cathode drive pulses b' to 0' are transferred to the vertical deflection counter (25) using a shift register, and the line cathode drive pulse a'' is transferred to the vertical deflection counter (25).
This can be obtained by transferring the inverted version of the output (LSB+3) as a clock. This driving pulse a
″~0′ is inverted and made low potential only during each pulse period,
During other periods, the pulses are converted into linear cathode drive pulses a to 0 with a high potential of about 20 volts (FIG. 3(b)E), and are applied to each of the linear cathodes (2a) to (2o).

Each line cathode (2a) to (20) is heated by a prolonged current during the high potential of the drive pulses a to 0, and is heated so that it can emit electrons during the low potential of the drive pulse a"o. state is maintained.This allows 15 line cathodes (2
From a) to (2o), a low potential drive pulse a is applied to each of a) to (2o).
Electrons are emitted only during the 16H period when -o is added.

During periods when a high potential is applied, the line cathode (2a ) to (20) is more positive, so no electrons are emitted from the line cathodes (2a) to (2o). Thus, in the line cathode (2), during the effective vertical scanning period, the upper line cathode (2a)
Electrons are sequentially emitted from the top to the lower line cathode (20) every 16H period. The emitted electrons are pushed forward by the back electrode (1), pass through the opposing slits (10) of the vertical focusing electrode (3), and are focused in the vertical direction to form a flat electron beam. .

Next, line cathode drive pulses a~0 and vertical deflection signals υ, υ′
The relationship between the two will be explained using FIG. The vertical deflection signals υ, υ' change by IH in 16 steps during the 16H period of each line cathode drive pulse a to 0. The vertical deflection signals υ and υ' both have a center voltage of v4, and are configured to change in opposite directions so that υ increases sequentially and υ' sequentially decreases. These vertical deflection signals υ and υ' are applied to the electrode (13) of the vertical deflection electrode (4), respectively.
) and (13''), and as a result, the electron beams generated from the respective line cathodes (2a) to (2o) are vertically deflected in 16 steps, and as mentioned earlier, the electron beams are applied to the screen (9). At the top, one electron beam is deflected so as to draw a 16-line raster one line at a time from the top.

As a result of the above, electron beams are emitted from the 15 line cathodes (2a) to (2o) in order from those above them for each period of 161 (periods).
In addition, each electron beam is deflected one line at a time from the top to the bottom within 15 sections in the vertical direction, so that on the screen (9)-H, the electron beams are deflected one line at a time from the 1st line at the top to the 240th line at the bottom. The electron beam is vertically deflected line by line, and a total of 240 raster lines are drawn.

The vertically deflected electron beam is connected to the control electrode (5).
It is horizontally divided into 184 sections by a horizontal focusing electrode (6) and a horizontal focusing electrode (6). Figure 1 shows one of these categories. The amount of this electron beam passing through each section is controlled by a control electrode (5), and is focused horizontally by a horizontal focusing electrode (6) into a single narrow electron beam. 2 on the screen (9).
The R2O and B fluorescent light bodies (20) corresponding to picture elements are sequentially irradiated. FIG. 2 shows the vertical and horizontal divisions. The phosphors corresponding to each of (15-1) to (15-n) of the control electrode (5) are R, G, and B for two picture elements, but for convenience of explanation, one picture element is R, G, and B. G,,B□ and the other R2,G
2. Let's call it B2.

Next, the horizontal deflection drive circuit (41) is composed of a horizontal deflection counter (28) (11 bits), a memory (29) that stores horizontal deflection signals, and a DA converter (38). . As shown in FIG. 7, the input pulses of the horizontal deflection drive circuit (41) are synchronized with the vertical synchronizing signal V and the horizontal synchronizing signal H, and a pulse 6H having a repetition frequency six times that of the horizontal synchronizing signal H is used. The horizontal deflection counter (28) is reset by the vertical synchronization signal ■ and receives the horizontal six times the pulse 6H.
Click the button. This horizontal deflection counter (28) is counted 6 times during LH and 24Of(X6/H=1) during 1V.
It counts 440 times, and this count output is stored in the memory (29
) is supplied to the address.

The memory (29) outputs horizontal deflection signal data (here, 8 bits) according to the address, and the D-A converter (38) converts it to the data shown in Fig. 7 (Fig. 3 (b) C). ,
It is converted into a horizontal deflection signal such as h'. This circuit has memory addresses for storing horizontal deflection signals corresponding to each of 5 x 240 lines, and by storing 6 pieces of regular data for each line in the memory, 6 step waves can be generated during the IH period. horizontal deflection signals can be obtained.

As shown in Fig. 7, this horizontal deflection signal is a pair of horizontal deflection signals ri and h' that change in 6 steps, both of which have a center voltage of v7, where h decreases sequentially and h' increases sequentially. They change in opposite directions as they move forward. These horizontal deflection signals, h' are the electrode (1) of the horizontal deflection electrode (7), respectively.
8) and (18'). As a result, each horizontally segmented electron beam is applied to the R, G of the screen (9) during each horizontal period.

B, R, G, B (R□=Gx, Bx, R2-G2.
It is horizontally deflected so that the phosphor of B2) is sequentially irradiated for H/6 periods. Thus, in each line raster, the electron beam is R□,
G1. B1. R2, G2. Each phosphor of B2 (2
0) are sequentially irradiated.

Therefore, for each horizontal section of each line, the electron beam is
□, B1. R2, G2. By modulating with the B2 video signal, a color television image can be displayed on the screen (9).

Next, the modulation control portion of the electron beam will be explained. First, the composite video signal applied to the television signal input terminal (23) is applied to the color demodulation circuit (30), where the R-Y and B-Y color difference signals are demodulated and the G-Y color difference signal is demodulated. The signals are matrix-synthesized, and further, they are combined with the luminance signal Y to form each primary color signal of R2O and B (hereinafter R,
G, B video signals) are output. Those R,G
, B. Each video signal is processed by 184 sample and hold circuits (3
1-]) to (31-n). Each sample-and-hold circuit (31-1) to (31-n) has six sample-and-hold circuits for R1, G1, B1, R2, G2, and B2. These sample and hold outputs are stored in the holding memories (32-1) to (32-1), respectively.
−n).

On the other hand, the reference clock oscillator (33) is constituted by a PT, L(needs-locked loop) circuit, etc., and in this conventional example, it is a standard clock 6f which is six times as large as the color subcarrier fsc.
A reference clock 2fSC, which is twice as much as the reference clock 2fSC, is generated. The reference clock is controlled to always have a constant phase with respect to the horizontal synchronizing signal H. The reference clock 2fsc is added to the deflection pulse generation circuit (42), and a signal 6H which is six times the horizontal synchronizing signal H and a signal switching pulse I every H/6 are added.
”1t g1+ bx*rz+gz+bz (Figure 3 (b
) The pulse of B) is obtained.

On the other hand, the reference clock 6fsc is applied to the sampling pulse generation circuit (34), where it is delayed by one clock period by a shift register, so that the horizontal period (
The effective horizontal scanning period (approximately 50
1104 sampling pulses R during μ5ec)
11, G11. B□1. R42, G,, B12
．． R21, G21°B21. R2□, G, 2. B2
．． ~Rn□, Gn,, Bnl, Rn2゜Gn,, B
n2 (FIG. 3(b) A) are generated sequentially, and then one transfer pulse t is generated. These sampling pulses R□1 to Bn2 correspond to each picture element when one line of the video to be displayed is divided into 368 picture elements in the horizontal direction, and their positions are always constant with respect to the horizontal synchronizing signal H. controlled so that

These 1104 sampling pulses R□1 to Bn2 each form 184 sets of sample hold circuits (31-1)
~(31-n), and as a result, each sample-and-hold circuit (31-1) to (31,-n) has 2 picture elements each when one line is divided into 184 pieces. R□, G1. Each video signal of Bi, R2, G, B2 is individually sampled and held.

The 184 sets of R1, G engineering whose samples were held,
B1. R2°G2. The video signal of B2 is stored in 184 sets of memory (32-1) after completing the sample hold for one line.
~(32-n) are transferred all at once by a transfer pulse t, and held here for the next horizontal period. This retained R-work.

G1. B1. R2, G2. The signal B is applied to switching circuits (35-1) to (35-n). The switching circuits (35-1) to (35-n) each have R1, G1 . B1°R2, G2. It is composed of a tri-state or analog gate having individual cooling power terminals of B and a common output terminal that sequentially switches and outputs them.

The output of each switching circuit (35-1) to (35-n) is 184 sets of pulse width modulation (PWM) circuits (37-1)
~(37-n), where the sample-held R1. G1. ' B1. R2,02,'B2
The reference pulse signal is pulse width modulated according to the magnitude of the video signal and output. The repetition period of the reference pulse signal is the above signal switching pulse r□v gxt blv
It is desirable that the pulse width is sufficiently smaller than the pulse width of I''ztg2vbz, for example, 1:10 to 1:
About 100 are used.

The outputs of the pulse width modulation circuits (37-1) to (37, -n) are sent to the 184 conductive plates (15-1) of the control electrode (5) of the display element as a control signal for modulating the electron beam.
~(15-n) are individually added to each. Each switching circuit (35-1) to (35-n) receives a switching pulse r1y gxt blv ray g2* bz applied from a switching pulse generating circuit (36).
Switching is controlled at the same time by The switching pulse generation circuit (36) is the aforementioned deflection pulse generation circuit (42).
Signal switching pulse from rzy g'1e bx* r
2y g2 * b2, each horizontal period is divided into 6 and a switching circuit (35-1
) to (35-n), R□, G1. B□, R2,
A switching signal r1p glt bxtrz+ gzy is used to time-divide and sequentially output each video signal of G, , B2 and supply it to the pulse width modulation circuits (37-1) to (37-n).
Generate b2.

What should be noted here is that the switching circuit (35-1
) to (35-n) R1. G., B1.
R2°G2. B2 video signal supply switching and electron beams R1, G1 . B1
．． R.

The irradiation switching horizontal deflection of G2tB2 to the phosphor is synchronously controlled so that it completely matches both the timing and the order. As a result, when the electron beam is irradiating the R1 phosphor, the irradiation amount of the electron beam is controlled by the R1 video signal, and the G1. B
1. R,,G2. B2 is similarly controlled, and R1, G, , B□ of each picture element.

R2=021B! The light emission of each phosphor is R4, G of that picture element.
1°B, , R2, G2. Each picture element is controlled by the B2 video signal, and each picture element is displayed by emitting light according to the input video signal. Such control is performed simultaneously for 184 sets (2 picture elements each) for one line, and an image of 368 picture elements per line is displayed, and an image of 368 picture elements for one line is displayed.
The H minute line is performed sequentially from the upper line,
One image will be displayed on the screen (9).

The above operations are performed on one input television signal.
This is repeated for each field, and as a result, a moving television image is displayed on the screen (9) in the same way as a normal television receiver.

Next, we will explain the sample and hold circuit in more detail in Figure 8 (a).
Explain using. Here, only the R output of the color demodulation circuit (30) will be explained, but G other than R.

Of course, the B output also has the same configuration. First, R
The output is a digital signal (44) from the A-D converter (43).
is converted to Here, it will be explained as 6 bits. This 6-bit output (44) has 368 latches (R
1t) (R1□)(R21)(R22)...(R
, □) (R-2). A-D converter (43)
The sampling clock of is 2fgc, and each latch (
Rx x ) (Rx 2 ) (R2□) (R22)
...(R-1) (Rゎ2) latch pulse is R11,
R□2. R23, R2□...Rn1. RT12 (see Figure 3). In this configuration, if, for example, a digital R signal is to be input directly, a configuration as shown in FIG. 8(b) can be considered. Generally, it is assumed that it will be used as a display for a personal computer. In this case, the video input R and the digital external human power Ruxt are respectively connected to the analog switches (45) and (46) which are switched by the input switching signal SW1, and the other ends of the two analog switches (45 and 46) are connected to each other. Figure 8 (
Connected to the R terminal of a). The inverter (47) is for switching control of the analog switches (45) and (46). However, in such an embodiment, the signal level of the digital external input REXT must be matched with the video input R in advance, and what is originally a digital signal must be sampled again by the A-D converter (43). You will have to do the same thing again. Moreover, although the resulting digital signal (44) is 6-bit information, it may actually be binary information, and unnecessary quantization noise may be added. In addition, digital external input REXT and other digital external input G EX
Generally, both T + B EXT are originally input at TTL level, and if you try to change the white balance, it is necessary to add a circuit to the front stage to match the level with the above-mentioned video input R. Not only that, but a level adjustment circuit is also required. Therefore, in general, these additional circuits are not added at all, and the input dynamic range of the A-D converter (43) is set to 2 to 3 V, and the digital external input REXT+ is connected directly as shown in Figure 8 (b).
GEXTtBl! Taking advantage of the fact that the XT and the like have a TTL level of 5 Vp-p, the A-D converter (43) is saturated and the output digital signal (44) is often used as all bits on or all bits off.

OBJECTS OF THE INVENTION It is an object of the present invention to provide an image display device that eliminates the drawbacks seen in the above-mentioned conventional examples and has a configuration in which the white balance for digital external input can be set completely independently of the video input. It is something.

Structure of the Invention According to the present invention, a second digital external input signal different from the input video signal can be input to a means for driving an electrode that controls the amount of electron beams irradiated onto a screen according to a video signal. and a first switch means for selecting either the output of the A-D converter of the input video signal built into the drive means and the second digital external input, and the second digital external input signal. A second means is provided which allows input by selecting any one bit or multiple bits of the output of the A-D converter, thereby making it possible to input digital data without the need for any additional circuitry. In addition to being able to directly input external input signals,
This has the advantage that the white balance of the input digital external signal can be set independently of the video signal.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. This also corresponds to the conventional example, and only the R signal will be explained.
A similar configuration can be used for other G and B signals. FIG. 9 shows that the digital signal of the output of the A-D converter (43) is supplied to the latch group via the tri-state buffer (48), while the digital external input REXT is connected to the white balance setting switch (50) and the tri-state buffer. - Connected to the same latch group via a buffer (49).

The tri-state buffers (48) and (49) are controlled by the input switching signal SW1, and the inverter (
47) is also the same as the conventional example. According to this configuration, first, the digital external human power REXT does not require any level conversion. In general, an A-D converter (
Everything after the output of 43) is a digital signal, and TTL
This is because there is no problem if it is at the level. Next, select the input signal bit using the white balance setting switch (50) and turn on any bit for the digital external input.
and unnecessary bits can always be turned off. This setting switch (50) can be used in conjunction with other setting switches corresponding to G and B signals to set the white balance. The setting switch (50) in FIG. 9 is shown as being set so that only two bits, MSB and MSB-1, are turned on and off by digital external manual input REXT, for example.

Effects of the Invention As described above, according to the present invention, not only can digital external signals from a personal computer or the like be directly inputted without using a level converter, but also the white balance of the inputted digital external signal can be changed into a video signal. It can be set independently of the signal.

This makes it extremely easy to adjust the lack of brightness of blue, which is a problem with computer input time, and has extremely great practical value.

[Brief explanation of drawings]

Figure 1 is a diagram showing the internal configuration of the image display unit, Figure 2 is an enlarged view of the image display unit, Figure 3 is a block diagram showing the basic configuration of the drive circuit and waveform diagrams of each part, and Figure 4 is the vertical deflection waveform. Depart□
Figure 5 is a diagram explaining the principle and timing of line cathode drive waveform generation.
Fig. 6 is a diagram showing the relationship between the line cathode drive pulse, vertical deflection signal, and horizontal deflection signal, Fig. 7 is a diagram explaining the principle and timing of horizontal deflection waveform generation, and Fig. 8 is a diagram showing the sample and hold circuit in the conventional example. A specific configuration diagram and an example diagram of a switching circuit with an external input terminal, and FIG. 9 is a circuit diagram showing an embodiment of a main part of a sample hold circuit and an external input terminal switching circuit according to the present invention. (1)... Back electrode, (2) (2a) to (2o).
...Line cathode, (3)...Vertical deflection electrode, (3')...
・Auxiliary electrode, (4)... Vertical deflection electrode, (5)...
Beam current control electrode, (6)...Horizontal focusing electrode, (7
)...Horizontal deflection electrode, (9)...Screen plate, (
24)...Sync separation circuit, (30)...Color demodulation circuit, (31-1) to (31-n)...Sample hold circuit, (32-1) to (32-n)...・Memory for holding video data, (33)...Reference clock oscillator, (3
4)...Sampling pulse generation circuit, (37-1)
-(37-n)-Pulse width modulation (PWN) circuit, (4
3) (44)...A-D converter output line, (47
)... Inverter for input signal selection switch, (4
8) Tri-state buffer (input video signal switch), (49) Tri-state buffer (external input video signal switch), (50) White balance setting switch (external input signal bit selection) Switch) Agent Yoshihiro Morimoto Figure 3 = Nidata Figure 2/J? Ri〃 day

Claims (1)

[Claims] 1. The screen on the screen is vertically divided into a plurality of sections. An electron beam generation source that generates an electron beam is provided in each vertical section, and the electron beam is sequentially deflected in the vertical direction for each vertical section. An electrode is provided to display a plurality of lines in each vertical section, and an electron beam passage hole or slit is provided in the middle of the electron beam path from the electron beam generation source to the screen, which is divided into a plurality of sections in the horizontal direction. and an electrode configured to control the emission intensity by controlling the amount of the electron beam irradiated onto the screen according to a video signal, and further deflecting the electron beam in the horizontal direction for each horizontal section. Electrodes are provided, different phosphors or other light-emitting substances are coated on the screen depending on the horizontal deflection position, and an image display element that enables color reproduction by horizontal deflection is installed, and the amount of electron beam irradiated onto the screen is displayed as an image. A second digital external input signal different from the input video signal can be inputted to the means for driving the electrodes controlled according to the signal, and an A-D converter for the input video signal built in the driving means can be inputted. A first switch means for selecting either the output or the second digital external input is provided, and the second digital external input signal is set to select any one or more bits of the output of the A-D converter. An image display device provided with a second switch means that enables selection and input corresponding to bits.