JPH06349423A - Image display device - Google Patents

Abstract

PURPOSE:To eliminate the capacity coupling to prevent the increase of the power consumption of an exclusive driving circuit amplifying unit, and to prevent the generation of deflection errors due to the breakdown of the waveform of the horizontal deflection by lowering the potential of a metal plate to a zero value, which is provided in the back of a vacuum vessel. CONSTITUTION:In an exclusive driving circuit having a vacuum vessel 1, an aluminum plate 2 and an exclusive driving circuit board 3, since an electrode inside of the container 1 and the board 3, namely, a glass of the container 1 and the aluminum plate 2 interpose the air to form a capacity, potential of the plate 2 provided in the back of the vessel 1 is lowered to a zero value. Capacity between the electrode inside of the vessel 1 and the exclusive driving circuit can be thereby absorbed. Consequently, power consumption of the exclusive driving circuit amplifying unit can be reduced, and the generation of deflection errors can be prevented without breaking the waveform of the deflection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generates an electron beam for each section when a screen on a screen is divided into a plurality of sections in the vertical direction, and emits each electron beam in the vertical direction for each section. The present invention relates to an image display device that deflects and displays a plurality of lines to display an image as a whole.

[0002]

2. Description of the Related Art The basic structure of a conventional image display device will be described with reference to FIG.

This display device has a back electrode 1, a line cathode 2 as a beam source, a beam extraction electrode 3, a beam flow control electrode 4, a focusing electrode 5 in this order from the rear to the anode side.
A horizontal deflection electrode 6, a vertical deflection electrode 7, a screen plate 8, etc. are arranged and configured, and these are housed inside a vacuum container. Also, a metal plate for heat dissipation is attached to the back side of the vacuum container. Here, an aluminum plate with a good heat dissipation effect is used as the metal plate.

A line cathode 2 as a beam source is stretched in the horizontal direction so as to generate an electron beam which is linearly distributed in the horizontal direction. (Only 7 of 2 a to 2 are shown)
It is provided. In this configuration, the line cathode spacing is 4.4 mm,
Assuming that 19 pieces are provided, the number of the line cathodes is 2 to 2 pieces. The distance between the line cathodes cannot be set freely, and is regulated by the distance between the vertical deflection electrode 7 and the screen 8 which will be described later. As the structure of these wire cathodes 2, an oxide cathode material is applied to the surface of a tungsten rod having a diameter of 10 to 30 μm. As will be described later, the above-mentioned line cathode is controlled so as to sequentially emit an electron beam from the upper line cathode 2a to the lower two line cathodes at regular intervals.

The back electrode 1 not only prevents the generation of electron beams from other line cathodes but also pushes out the electron beams only toward the anode. Although the vacuum container is not shown in FIG. 3, it is possible to use the back electrode 1 to form a structure integrated with the vacuum container.

The beam extraction electrode 3 is a conductive plate 11 having a plurality of through holes 10 which are arranged in a row in the horizontal direction facing each of the line cathodes 2a to 2 and are arranged at regular intervals, and are emitted from the line cathode 2. The electron beam is extracted through the through hole 10.

The control electrode 4 is composed of a vertically long conductive plate 15 having a through hole 14 at a position facing each of the line cathodes 2a to 2c, and a plurality of control electrodes 4 are horizontally arranged at predetermined intervals. Individually installed. In this configuration, 114 control electrode conductive plates 15a to 15n are provided (FIG. 3).
Shows only 8). The control electrode 4 controls the passing amount of each of the electron beams divided in the horizontal direction by the beam extraction electrode 3 in correspondence with the pixel of the video signal and in synchronization with the horizontal deflection timing described later.

The focusing electrode 5 is a conductive plate 17 having a through hole 16 at a position facing each through hole 14 provided in the control electrode 4, and focuses the electron beam.

The horizontal deflection electrode 6 is composed of a plurality of conductive plates 18 and 18 'vertically arranged along both sides of the through hole 16 in the horizontal direction. The deflection voltage is applied. The electron beam for each pixel is deflected in the horizontal direction, and the R, G, and B phosphors are sequentially irradiated on the screen 8 to emit light. In this configuration, each electron beam is deflected by 2 trio.

The vertical deflection electrode 7 is composed of a plurality of conductive plates 19 and 19 'horizontally arranged at intermediate positions in the vertical direction of the through hole 16, and a vertical deflection voltage is applied to the vertical deflection electrode 7. The electron beam is deflected vertically.
In this configuration, the electron beam generated from one line cathode is vertically deflected by 12 lines by the pair of electrodes 19 and 19 '. And a vertical deflection electrode 7 composed of 20 pieces
Defines 19 pairs of vertical deflection conductors corresponding to each of the 19 line cathodes and draws 228 horizontal scan lines vertically on the screen 8.

As described above, in this structure, a plurality of horizontal deflection electrodes 6 and vertical deflection electrodes 7 are arranged in a comb shape. Further, by setting the distance to the screen 8 longer than the distance between the horizontal and vertical deflection electrodes, it becomes possible to irradiate the screen 8 with the electron beam with a small deflection amount. As a result, horizontal and vertical co-deflection distortion can be reduced.

As shown in FIG. 6, the screen 8 is formed by coating the back surface of the glass plate 21 with the phosphor 20 in a stripe shape. Although not shown, metal back and carbon are also applied. The phosphor 20 is provided so as to horizontally deflect the electron beam passing through one through hole 14 of the control electrode 4 to irradiate the phosphor pairs of three colors R, G, and B for two trios. , Applied vertically in a stripe pattern. In FIG. 3, broken lines on the screen 8 indicate vertical divisions displayed corresponding to the plurality of line cathodes 2, and two-dot chain lines are displayed corresponding to each of the plurality of control electrodes 4. The horizontal division is shown. FIG. 7 shows an enlarged view of one section divided by a broken line and a two-dot chain line.

As shown in FIG. 7, two trio R, G, and B phosphors in the horizontal direction and a width of 12 lines in the vertical direction are provided. The size of one section is 1 in the horizontal direction in this example.
mm, vertical direction 4.4 mm. In FIG. 7, R, G,
Although the phosphors of three colors B are illustrated in a stripe shape, they may be arranged in a delta shape. However, when they are arranged in a delta shape, it is necessary to apply horizontal deflection and vertical deflection waveforms suitable for them. Note that, in FIG. 7, the vertical and horizontal dimensional ratios are different from the image actually displayed on the screen for convenience of description. Further, in the present configuration, two trio of R, G, and B phosphors are provided in one through hole 14 of the control electrode 4, but one trio or three trio or more may be configured. . However, 1 trio or 3 for the control electrode 4.
It is necessary to sequentially apply R, G, and B video signals above the trio and perform horizontal deflection in synchronization with them.

Next, the operation of the drive circuit for driving this display element will be described with reference to FIG. First, the drive part that irradiates the screen 8 with the electron beam to display the image will be described.

The power supply circuit 22 is a circuit for applying a predetermined bias voltage to each electrode of the display element. The back electrode 1 is V1, the beam emitting electrode 3 is V3, and the focusing electrode 5 is V3.
5. A DC voltage of V8 is applied to the screen 8.

The pulse generating circuit 39 uses the vertical synchronizing signal V and the horizontal synchronizing signal H to create a line cathode drive pulse.
FIG. 9 shows the timing chart. As shown in FIG. 8, the line cathode drive circuit 26 receives the line cathode drive pulse and heats the line cathode 2 while the drive pulse is at a high potential. At this time, since the potential applied to the line cathode 2 is higher than the potential around the line cathode 2 determined by the bias voltage applied to the back electrode 1 and the beam extraction electrode 3, Does not emit electrons.

On the other hand, the line cathode 2 emits electrons while the drive pulse is at a low potential. The line cathode at this time is the back electrode 1
Since the potential applied to the line cathode 2 is lower than the potential around the line cathode 2 determined by the bias voltage applied to the electron beam extraction electrode 3 and
Electrons are emitted from the line cathode 2.

As is apparent from the above description, electrons are emitted from the 19 line cathodes 2a to 2t only during the 12 horizontal scanning periods in which low potential drive pulses (a tot) are applied. In order to form one screen, it is sufficient to sequentially switch the potentials from the upper line cathode 2a to the lower line cathode 2 by 12 scanning periods.

Next, the deflecting portion will be described. As shown in FIG. 8, the deflection voltage generating circuit 40 includes a direct memory access controller (hereinafter referred to as a DMA controller) 41,
Memory for storing deflection voltage waveform (hereinafter referred to as deflection memory) 4
2, horizontal deflection signal generator 43h, vertical deflection signal generator 4
The vertical deflection signals v and v'and the horizontal deflection signals h and h'are generated. In this configuration, the vertical deflection signal is displayed in one field for 228 horizontal scanning periods in consideration of overscan. Further, the memory address area storing the vertical deflection position information corresponding to each line is divided into a first field and a second field, and each has a set of memory capacity.
When displaying, data is read from the corresponding deflection memory 42, converted into an analog signal by the vertical deflection signal generator 43v, and added to the vertical deflection electrode 7.

The vertical deflection position information stored in the deflection memory 42 is composed of data having a regularity for every 12 horizontal scanning periods, and the waveform converted into the deflection signal also has a vertical deflection signal of approximately 12 stages. However, the memory capacity for two fields is provided as described above, and the position can be finely adjusted for each horizontal scanning line.

Further, with respect to the horizontal deflection signal, it is necessary to horizontally deflect the electron beam in six steps in one horizontal scanning period, and a memory is provided so that the deflection position can be finely adjusted for each horizontal scanning. Therefore, in order to display 456 horizontal scanning periods in one frame, a memory of 456 × 6 = 2736 bytes is required, but since the data of the first field and the second field are shared, it is actually 1368 bytes. You are using memory. At the time of display, the deflection information corresponding to each horizontal scanning line is read from the deflection memory 42, converted into an analog signal by the horizontal deflection signal generator 43h, and added to the horizontal deflection electrode 6.

Summarizing the above, during the display period excluding the vertical blanking period of the vertical period, the low potential driving pulse of the linear cathodes 2a to 2 is emitted from the linear cathode. The electron beam is divided into 114 sections in the horizontal direction by the beam extraction electrode 3 to form 114 electron beam arrays. As will be described later, the electron beam has a beam passage amount controlled by the beam control electrode 4 for each section, and after being focused by the focusing electrode 5, a pair of horizontal beams which changes in approximately 6 stages as shown in FIG. Deflection signal h,
By the horizontal deflection electrodes 18 and 18 'to which h'is added,
In each horizontal display period, phosphors such as R1, G1, B1 and R2, G2, B2 of the screen 8 are sequentially displayed in the horizontal display period /
Irradiate 6 each.

Thus, the raster of each horizontal line is 11
A color image can be displayed on the screen 8 by modulating the electron beam for each of the four sections with the video signals corresponding to R1, G1, B1 and R2, G2, B2.

Next, the modulation control portion of the electron beam will be described. First, in FIG. 8, the signal input terminals 23R, 23
Each R, G, B video signal added to G, 23B is 1
It is added to 14 sample-hold circuit groups, 31a to 31n. The sample and hold groups 31a to 31n are respectively for R1, G1, B1, and R2, G2,
It is composed of six sample and hold circuits for B2. The sampling pulse generating circuit 34 has a horizontal cycle (63.
In the horizontal display period (about 50 μsec) of 5 μsec), each of the 114 sets of sample hold circuits 31a to 31n is for R1, G1, B1, and R2, G2, B2.
684 (114 corresponding to the sample and hold circuit for
× 6) sampling pulses Ra1 to Rn2 are sequentially generated. Each of the 684 sampling pulses is 1
Six samples are added to each of the 14 sample-hold circuit groups 31a to 31n, so that each sample-hold circuit group has R1, G1, B1, and R2 for two pixels when one line is divided into 114 pieces. , G2, and B2 video signals are individually sampled and held. 114 sets of sampled and held R1, G1, B1, R
The video signals of 2, G2, and B2 are simultaneously transferred by the transfer pulse t to 114 sets of memories 32a to 32n after the end of the sample hold for one line, and are held there for the next one horizontal scanning period.

The held signal is applied to 114 switching circuits 35a to 35n. Switching circuit 3
5a to 35n are R1, G1, B1, R2, and G, respectively.
2, B2, and a common output terminal for sequentially switching and outputting them, and a switching pulse r1, g1, b1, r2, g2, b2 applied from the switching pulse generating circuit 36.
Are simultaneously controlled by. The switching pulses r1, g1, b1, r2, and g2b2 divide each horizontal display period into six, and switch the switching circuits 35a to 35n by the horizontal display period / 6 every R1, G1, B1, R.
2, G2, B2 video signals are time-divided and sequentially output,
It is supplied to the pulse width modulation circuits 37a to 37n. The outputs of the switching circuits 35a to 35n are added to 114 sets of pulse width modulation (hereinafter referred to as PWM) circuits 37a to 37n, and the outputs of the switching circuits 35a to 35n are changed according to the magnitudes of the video signals of R1, G1, B1, R2, G2 and B2. Pulse width modulated and output.
The outputs of the pulse width modulation circuits 37a to 37n are individually applied as control signals for modulating the electron beam to the 114 conductive plates 15a to 15n of the control electrode 4 of the display element. The brightness of the screen can be adjusted by adjusting the pulse width.

Next, the timing of horizontal deflection and display will be described. R in the switching circuits 35a to 35n
Switching of the video signals of 1, G1, B1, R2, G2, and B2, and the electron beam R by the horizontal deflection signal generator 43h
The synchronization control is performed so that the switching timing and the order of horizontal deflection of the phosphors of 1, G1, B1, R2, G2, and B2 to the phosphors completely match. As a result, when the R1 phosphor is irradiated with the electron beam, the irradiation amount of the electron beam is controlled by the R1 control signal, and G1, B1, R
2, G2, B2 are controlled in the same manner, and the emission of each phosphor of R1, G1, B1, R2, G2, B2 of each pixel is the video signal of R1, G1, B1, R2, G2, B2 of that pixel. That is, each pixel is controlled to emit light according to an input video signal. This control is simultaneously executed for 114 sets (two pixels each) for one line, an image of 228 pixels for one line is displayed, and 228 lines for one field are sequentially performed from the upper line, and the screen 8 is displayed. The image is displayed above. Further, the above-described operations are repeated for each field of the input video signal, and the television signal or the like is displayed on the screen 8.

The basic clock required for this configuration is supplied from the pulse generating circuit 39 shown in FIG. 7, and the timing is controlled by the horizontal synchronizing signal H and the vertical synchronizing signal V.

[0028]

However, in the above structure, a capacitance is formed between the electrode in the vacuum container and the dedicated drive circuit immediately behind it, and the small signal portion of the dedicated drive circuit is disturbed. There is a problem that the power consumption of the amplifying unit is increased and the waveform of the horizontal deflection is broken to cause color shift.

The present invention addresses the above problems by removing the capacitive coupling and increasing the power consumption of the amplifier section of the dedicated drive circuit, and
An image display device is provided that prevents the occurrence of color misalignment by breaking the waveform of horizontal deflection.

[0030]

In order to solve the above problems, the image display apparatus of the present invention is one in which the metal plate provided on the back side of the vacuum container is dropped to zero potential.

[0031]

The present invention has the above-mentioned structure to prevent capacitive coupling between the electrode in the vacuum container and the dedicated drive circuit immediately behind it.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a perspective view of the vacuum container 1, the aluminum plate 2 and the dedicated drive circuit board 3, and FIG. 1B is a side view thereof. 2 and 4 are waveforms applied to the horizontal deflection electrode and the vertical deflection electrode when the potential of the aluminum plate provided on the back side of the vacuum container is floating, and FIGS. 3 and 5 show the aluminum plate 2 at 0 potential. It is a waveform applied to the horizontal deflection electrode and the vertical deflection electrode when dropped. In the figure, the horizontal axis is time,
The vertical axis represents voltage.

The portion (a) of FIG. 2 causes a color shift on the screen, and the portion (b) of FIG. 4 is a factor for increasing the power consumption of the dedicated drive circuit. Here, since the capacitance is formed between the electrodes inside the vacuum container 2 and the dedicated drive circuit board 3, that is, the glass of the vacuum container 1, the aluminum plate 2 and the air are sandwiched, the capacitance is formed. I was disturbed as in 4 (b).

Therefore, the aluminum plate provided on the back side of the vacuum container is dropped to 0 potential to absorb the capacitance between the electrode in the vacuum container and the dedicated drive circuit, and the waveform applied to the vertical and horizontal deflection electrodes. Is as shown in FIGS. 3 and 5 from which FIGS. 2 (a) and 4 (b) are removed.

Although the metal plate is made of aluminum here, the same effect can be obtained by using iron or copper.

[0037]

As described above, according to the present invention, by setting the metal plate provided on the back side of the vacuum container to zero potential, it is very easy to increase the capacitance between the electrode in the vacuum container and the dedicated drive circuit. It is possible to reduce the power consumption of the amplification section of the dedicated drive circuit and prevent the occurrence of color misregistration without breaking the deflection waveform.

[Brief description of drawings]

FIG. 1A is a perspective view of a vacuum container, a metal plate and a dedicated drive circuit according to an embodiment of the present invention. FIG. 1B is a side view of a vacuum container, a metal plate and a dedicated drive circuit according to an embodiment of the present invention.

FIG. 2 is a waveform diagram applied to the horizontal deflection electrode when the electric potential of the aluminum plate provided on the back side of the vacuum container is floating.

FIG. 3 is a waveform diagram applied to the horizontal deflection electrode when the potential of the aluminum plate provided on the back side of the vacuum container is set to 0 potential.

FIG. 4 is a waveform diagram applied to the vertical deflection electrode when the electric potential of the aluminum plate provided on the back side of the vacuum container is floating.

FIG. 5 is a waveform diagram applied to the vertical deflection electrode when the potential of the aluminum plate provided on the back side of the vacuum container is set to 0 potential.

FIG. 6 is an exploded perspective view of an image display device.

FIG. 7 is an enlarged front view of the screen.

FIG. 8 is a block diagram of a drive circuit

FIG. 9 is a waveform chart of each part for explaining the operation of FIG.

[Explanation of symbols]

 1 Vacuum container 2 Aluminum plate 3 Dedicated drive circuit board

Claims (1)

[Claims] 1. A screen coated with a phosphor that emits light when irradiated with an electron beam, and an electron beam for generating an electron beam for each vertical section obtained by vertically dividing the screen on the screen into a plurality of sections. Source, separation means for separating the electron beam generated by the electron beam source in each horizontal section into horizontal sections, and irradiating the screen with the electron beam; and a vertical direction between the electron beam and the screen. And a deflection electrode for deflecting in a plurality of steps in the horizontal direction, and a beam flow for controlling the amount of irradiation of the screen with the electron beam separated for each of the horizontal sections to control the light emission amount of each pixel on the screen of the screen. A control electrode, a focusing electrode that controls the size of light emitted by the electron beam on the phosphor surface in each pixel, a back electrode that controls the electron beam amount, and the electron beam. An image display device, comprising: a beam extraction electrode for controlling the total amount of heat radiation; and a metal plate for heat radiation between a vacuum container and a dedicated drive circuit board, wherein the metal plate for heat radiation has an electric potential.