JP2745861B2 - Image display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

This display element comprises 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,
A horizontal deflection electrode 6, a vertical deflection electrode 7, a screen plate 8, and the like are arranged and configured, and these are housed inside a vacuum vessel.

A linear cathode 2 as a beam source is stretched in the horizontal direction so as to generate an electron beam distributed linearly in the horizontal direction. Only 7 lines 2a to 2g are shown.) In this configuration, the distance between the line cathodes is 4.4
mm, the number of the line cathodes is assumed to be 2 to 2 assuming that 19 are provided. The distance between the line cathodes cannot be freely increased, and is regulated by the distance between a vertical deflection electrode 7 and a screen 8 described later. These line cathodes 2
The oxide cathode material is applied to the surface of a tungsten rod having a diameter of 10 to 30 μm. The line cathode is controlled so as to emit an electron beam from the upper line cathode 2a to the lower two line cathodes in order for a predetermined time, as described later. The back electrode 1 not only suppresses the generation of electron beams from the line cathodes other than the corresponding line cathode, but also pushes out the electron beams only in the anode direction. Although a vacuum vessel is not shown in FIG. 3, a structure that is integrated with the vacuum vessel using the back electrode 1 is also possible. A large number of beam extraction electrodes 3 are provided in a through-hole 10 provided at regular intervals in the horizontal direction facing each of the linear cathodes 2a to 2a.
The electron beam emitted from the linear cathode 2 is extracted through the through-hole 10. Next, 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 linear cathodes 2a to 2a. Have been. In this configuration, 114 control electrode conductive plates 15a
To 15n are provided. (Only eight lines are shown in FIG. 3).

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 accordance with the picture element of the video signal and in synchronization with the horizontal deflection timing described later. doing. 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 an electron beam. The horizontal deflection electrode 6 is composed of a plurality of conductive plates 18 and 18 ′ arranged in the vertical direction along both sides of the through hole 16 in the horizontal direction. Is applied. The electron beam for each picture element is deflected in the horizontal direction, and emits light by sequentially irradiating the R, G, and B phosphors on the screen 8. In this configuration, each electron beam is deflected by two trios.

The vertical deflection electrode 7 is composed of a plurality of conductive plates 19 and 19 ′ arranged in the horizontal direction at intermediate positions in the vertical direction of the through holes 16, respectively. The electron beam is deflected vertically.
In this configuration, an electron beam generated from one linear cathode is deflected by 12 lines in the vertical direction by a pair of electrodes 19 and 19 '. And a vertical deflection electrode 7 composed of 20 electrodes.
Thus, 19 vertical deflection conductor pairs corresponding to each of the 19 line cathodes are formed, and 228 horizontal scanning lines are drawn on the screen 8 in the vertical direction. As described above, in this configuration, a plurality of horizontal deflection electrodes 6 and vertical deflection electrodes 7 are stretched in a comb shape. Further, by setting the distance to the screen 8 longer than the distance between the horizontal and vertical deflection electrodes, the screen 8 can be irradiated with the electron beam with a small deflection amount. Thereby, horizontal and vertical co-deflection distortion can be reduced.

[0007] As shown in FIG. 3, the screen 8 is formed by applying a phosphor 20 on the back surface of a glass plate 21 in a stripe shape. Also not shown, metal back,
Carbon is also applied. The phosphor 20 is provided so as to irradiate two trios of phosphor pairs of three colors of R, G and B by deflecting the electron beam passing through one through hole 14 of the control electrode 4 in the horizontal direction. , In the form of stripes in the vertical direction. In FIG. 3, the dashed lines drawn on the screen 8 indicate vertical divisions displayed corresponding to the plurality of line cathodes 2, and the two-dot chain lines correspond to each of the plurality of control electrodes 4. Indicates the horizontal division displayed. An enlarged view of one section separated by a broken line and a two-dot chain line is shown in FIG.

[0008] As shown in FIG. 4, the phosphor has R, G, and B phosphors in two horizontal directions and 12 lines in the vertical direction. In this example, the size of one section is 1 mm in the horizontal direction and 4.4 mm in the vertical direction. In FIG. 4, R,
Although the phosphors of the three colors G and B are shown 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 a horizontal deflection and vertical deflection waveform suitable for the delta shape. In FIG. 4, the size ratio in the vertical and horizontal directions is different from the image displayed on the actual screen for convenience of explanation. In this configuration, the R, G, and B phosphors are provided for two trios for one through hole 14 of the control electrode 4, but may be configured for one trio or three or more trios. . However, one trio or three or more R, G, B video signals are sequentially applied to the control electrode 4, and it is necessary to perform horizontal deflection in synchronization with the trio.

Next, the operation of the drive circuit for driving the display element will be described with reference to FIG. First, a driving portion for irradiating the screen 8 with an electron beam for display will be described. The power supply circuit 22 is a circuit for applying a predetermined bias voltage to each electrode of the display element.
1, V3 for the beam extraction electrode 3 and V for the focusing electrode 5
5. A DC voltage of V8 is applied to the screen 8.

The pulse generating circuit 39 generates a line cathode driving pulse using the vertical synchronizing signal V and the horizontal synchronizing signal H.
FIG. 6 shows the timing chart. Each line cathode 2a ~ 2
As shown in ((Fig. 5 (a) to (m)), the current is heated by a current flowing while the drive pulse is at a high potential, and electrons are emitted during the period when the drive pulse (i to ma) is at a low potential. The heating state is maintained.

As a result, electrons are emitted from the 19 line cathode rays 2a to 2 only during 12 horizontal scanning periods to which low-potential drive pulses (a to d) are applied. In order to compose one screen, the potential may be changed by sequentially switching the potential from the upper line cathode 2 to the lower line cathode 2 every 12 scanning periods.

Next, the deflection portion will be described. The deflection voltage generation circuit 40 includes a direct memory access controller (hereinafter, referred to as a DMA controller) 41, a deflection voltage waveform storage memory (hereinafter, referred to as a deflection memory) 42, a horizontal deflection signal generator 43h, a vertical deflection signal generator 43v, and the like. And generates a vertical deflection signal v, v 'and a horizontal deflection signal h, h'. In this configuration, the vertical deflection signal is displayed in one field for 228 horizontal scanning periods in consideration of overscan. Further, a memory address area storing vertical deflection position information corresponding to each line is divided into a first field and a second field, each having one set of memory capacity. When displaying, the data is read from the corresponding deflection memory 42, converted into an analog signal by the vertical deflection signal generator 43v, and applied to the vertical deflection electrode 7. The vertical deflection position information stored in the deflection memory 42 is composed of data having substantially regularity every 12 horizontal scanning periods, and the waveform converted into a deflection signal is also a vertical deflection signal having almost 12 steps. However, as described above, a memory capacity for two fields is provided, and the position can be finely adjusted for each horizontal scanning line. For a horizontal deflection signal, it is necessary to horizontally deflect the electron beam in six stages during one horizontal scanning period, and a memory is provided so that the deflection position can be finely adjusted for each horizontal scanning. Therefore 1
Assuming that 456 horizontal scanning periods are displayed between frames, 45
Although 6 × 6 = 2736 bytes of memory is required, the first
Since the data of the field and the second field are shared, 1368 bytes of memory are actually used. At the time of display, deflection information corresponding to each horizontal scanning line is read from the deflection memory 42, converted into an analog signal by a horizontal deflection signal generator 43h, and applied to the horizontal deflection electrode 6.

In summary, during the display period excluding the vertical blanking period in the vertical cycle, the electron beam emitted from the line cathode to which the low-potential drive pulse of the two line cathodes 2a to 2 is applied. Are divided into 114 sections in the horizontal direction by the beam extraction electrode 3 to constitute a row of 114 electron beams. The passing amount of the electron beam is controlled by the control electrode 4 for each section as described later, and after being converged by the converging electrode 5, a pair of electron beams that change in approximately six steps as shown in FIG. During each horizontal display period, R1, G1, B1 and R2 of the screen 8 are controlled by horizontal deflection electrodes 18, 18 'to which horizontal deflection signals h, h' are added.
The phosphors such as G2 and B2 are sequentially irradiated with a horizontal display period / 6. Thus, the raster of each horizontal line is 114
The electron beams are divided into R1, G1, B1 and R
2, G2, and B2, a color image display can be displayed on the screen 8.

Next, the modulation control portion of the electron beam will be described. First, in FIG. 5, the signal input terminals 23R,
Each of the R, G, and B video signals applied to the 23G and 23B has 114 sets of sample and hold circuits, 31a to 31
n. Each sample and hold circuit set 31a-3
1n is for R1, G1, B1, and R2, respectively.
, G2, and B2. The sampling pulse generating circuit 34 controls the horizontal display period (approximately 5
At 0 μsec), 684 (114 × 6) samplings corresponding to the R1, G1, and B1 and the R2, G2, and B2 sample and hold circuits of the 114 sets of sample and hold circuits 31a to 31n, respectively. Pulse Ra
1 to Rn2 are sequentially generated. The 684 sampling pulses are applied to the 114 sample-and-hold circuit sets 31a to 31n, each of 6 pieces, so that each sample-and-hold circuit set has two picture elements when one line is divided into 114 pieces. Minute R1, G1, B1, R
2, G2 and B2 are individually sampled and held. 114 sets of R sampled and held
The video signals of 1, G1, B1, R2, G2, and B2 are stored in 14 sets of memories 32a after one line of sample and hold is completed.
To 32n are simultaneously transferred by the transfer pulse t, and are held here for the next one horizontal scanning period. This retained R
The signals of 1, G1, B1, R2, G2, and B2 are applied to 114 switching circuits 35a to 35n. The switchg circuits 35a to 35n are respectively R1, G1,
The switching pulses r1, g1, b1, and r applied from the switching pulse generation circuit 36 include a circuit having individual input terminals of B1, R2, G2, and B2 and a common output terminal for sequentially switching and outputting the same.
2, g2 and b2 are simultaneously controlled. The switching pulses r1, g1, b1, r2, g2
b2 is obtained by dividing each horizontal display period into six, and
Switching the switching circuits 35a to 35n by 6
The video signals 1, G1, B1, R2, G2, and B2 are time-divided and sequentially output, and supplied to pulse width modulation circuits 37a to 37n. Outputs of the respective switching circuits 35a to 35n are applied to 114 sets of pulse width modulation (hereinafter referred to as PWM) circuits 37a to 37n, and R1, G1, B1, R
2, G2, and B2, and pulse width modulated according to the magnitude of each video signal and output. These pulse width modulation circuits 37a-3
The output of 7n is used as a control signal for modulating the electron beam as 114 control plates 15a-1 of the control electrode 4 of the display element.
5n, respectively.

Next, the timing of horizontal deflection and display will be described. R in switchg circuits 35a to 35n
, G1, B1, R2, G2, and B2 video signal switching, and the electron beam R generated by the horizontal deflection signal generator 43h.
Synchronous control is performed so that the timing and the switching timing of the horizontal deflection of the phosphors 1, G1, B1, R2, G2, and B2 completely match. Thus, when the electron beam is irradiated on the R1 phosphor, the irradiation amount of the electron beam is controlled by the R1 control signal, and hereinafter G1, B1, R
2, G2, and B2 are similarly controlled, and the light emission of each of the phosphors R1, G1, B1, R2, G2, and B2 of each picture element is determined by the R1, G1, B1, R2, G2, and B2 of that picture element. Each picture element is controlled by the video signal, and each picture element is illuminated and displayed according to the input video signal.
This control is performed simultaneously for 114 sets (two picture elements) for one line, an image of 228 picture elements per line is displayed, and 228 lines per field are sequentially performed from the upper line. An image is displayed on the screen 8. Further, the above operations are repeated for each field of the input video signal, and a television signal or the like is displayed on the screen 8.

The basic clock required for this configuration is supplied from a pulse generation circuit 39 shown in FIG. 5 and the timing is controlled by a horizontal synchronizing signal H and a vertical synchronizing signal V.

As described above, all of the drive circuits shown in FIG. 5 except for the power supply circuit 22 are on one circuit print.

[0018]

However, in the above configuration, the number of control signals for each circuit and the number of drive signals for each electrode are enormous. A layered circuit board must be used, which is expensive.

Another problem is that if a two-layer (double-sided) circuit printed board is used and wiring is forcibly performed, the OV wiring foil becomes thin and noise is generated.

The present invention has been made in view of the above problems, and provides an image display apparatus which displays a beautiful image at low cost with little noise by a simple method.

[0021]

In order to solve the above-mentioned problems, an image display device according to the present invention comprises a circuit printed board for a drive circuit, one or more metal plates for sandwiching the circuit printed board and shielding. A metal rod is provided on the OV wiring foil on the printed board and connects the wiring foil and the metal plate.

[0022]

According to the present invention, even if a two-layer circuit printed board is used, the OV is stabilized by connecting the wiring foil of the OV and the shielding metal plate at a plurality of locations with a plurality of metal rods. A beautiful image with few images can be provided at low cost.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image display device according to an embodiment of the present invention will be described below with reference to the drawings. (Fig. 1 and Fig. 2)
FIG. 1 shows a sectional view and an exploded perspective view of an image display element and a drive circuit of an image display device according to an embodiment of the present invention.

In the drawing, reference numerals 101A and 101B denote shielding metal plates for shielding a circuit printed board 102 constituting a drive circuit. Reference numeral 103 denotes a back metal plate of the image display element. Reference numeral 105 denotes an electrode drive terminal for driving a certain beam flow control electrode 4 inside the image display element. Electrically connected. 104 is an OV on the printed board 102
Is a metal rod that connects the wiring foil and the shielding metal plate 101A.

In the image display element and the driving circuit configured as described above, the metal bar 104 could not be connected to a thin portion of the OV wiring foil on the printed board 102 or a two-layer printed board. By soldering the metal bar 104 to the shielding metal plate 101A, the potential of the OV is stabilized, and the performance similar to a four-layer printed board with little noise can be realized at low cost. it can.

Although two metal rods 104 are used in the above description, more than two metal rods can be used.

[0027]

As described above, according to the present invention, it is possible to stabilize the potential of the OV, to realize a low-noise performance equivalent to a four-layer printed board at a low cost, and to display a beautiful image. .

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an image display device and a driving circuit of an image display device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a line-cathode driving circuit and a line-cathode protection circuit of the image display device.

FIG. 3 is an exploded perspective view of an image display element used in the present invention.

FIG. 4 is an enlarged view of a phosphor screen of the image display device.

FIG. 5 is a drive circuit block diagram of the image display device.

FIG. 6 is a waveform chart for explaining the operation of the image display device.

[Explanation of symbols]

 101A, 101B Shield metal plate 102 Rotating printed board of drive circuit 103 Back metal plate 104 Metal rod 105 Electrode drive terminal

Claims (1)

(57) [Claims] 1. A vacuum envelope having a face plate and a back metal plate, a plurality of linear cathodes arranged in the vacuum envelope to generate an electron beam, and an electron beam emitted from the linear cathode. An image display element comprising a control electrode for controlling, a fluorescent film formed on the inner surface of the face plate and emitting light by the intrusion of an electron beam, and a circuit for driving the line cathode and the control electrode; A printed circuit board for displaying an image on the printed circuit board, one or more shielded metal plates sandwiching the printed circuit board for shielding, and the wiring foil and the shielded metal plate on a 0 V wiring foil on the printed circuit board. An image display device, comprising: a metal rod for connecting the image display device.