JPH0771191B2 - Image display device - Google Patents

Description

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 each electron beam is generated for each section. The present invention relates to an apparatus for displaying a plurality of lines by vertically deflecting a vertical axis to display a television image and an image similar thereto.

2. Description of the Related Art In recent years, a number of display devices intended for thin type have been developed and commercialized, and a new image display device shown in Japanese Patent Application No. 56-20618 (see Japanese Patent Application Laid-Open No. 57-135590). Is proposed.

Hereinafter, an example of the conventional deflection circuit for an image display device will be briefly described with reference to the drawings.

This is because when the screen on the screen is divided into a plurality of sections in the vertical direction, an electron beam is generated for each section, and each electron beam is deflected in the vertical direction to display a plurality of lines. However, as a whole, the television image is displayed.

First, a basic configuration of the image display device used here will be described with reference to FIG. This display element comprises a back electrode 1, a line cathode 2 as a beam source, vertical focusing electrodes 3 and 3'vertical deflection electrodes 4, a beam current control electrode 5, a horizontal focusing electrode 6 and a horizontal deflection electrode in this order from the rear to the front. An electrode 7, a beam accelerating electrode 8 and a screen 9 are arranged and housed, and these are housed in a vacuumed inside of a flat glass bulb (not shown). A line cathode 2 as a beam source is stretched in the horizontal direction so as to generate an electron beam that is linearly distributed in the horizontal direction. A plurality of such line cathodes 2 are vertically arranged at appropriate intervals (in the figure, 4 of 2a-2d
Only the book is shown). In this example, 15 are provided. Let them be 2a to 2o. These wire cathodes 2 are formed by coating a surface of a tungsten wire of 10 to 20 .mu..phi. With an oxide cathode material for emitting thermoelectrons. Then, these line cathodes 2a to 2o are heated so that a thermoelectron beam can be generated by passing an electric current, and as will be described later, the electron beam is emitted from the above line cathode 2a in order for a certain period of time. Controlled as.
The back electrode 1 suppresses the generation of an electron beam from a line cathode other than the line cathode controlled to emit the electron beam for a certain period of time, and pushes out the generated electron beam only in the forward direction. To work.

The back electrode 1 may be formed by a coating film of a conductive material attached to the inner surface of the rear wall of the glass bulb. Further, instead of the back electrode 1 and the line cathode 2, a planar electron beam emitting cathode may be used.

The vertical focusing electrode 3 is a conductive plate 11 having a horizontally long slit 10 facing each of the line cathodes 2a to 2o. The electron beam emitted from the line cathode 2 is taken out through the slit 10 and vertically. Focus. Horizontal 1
Simultaneous extraction of electron beams for lines (360 pixels). In the figure, only one horizontal section is shown. The slits 10 may be provided with a groove at appropriate intervals in the middle, or a plurality of rows of through-holes arranged side by side at a small horizontal interval (an interval at which they are almost in contact) are formed substantially as slits. May be done. The vertical focusing electrode 3'is also the same.

A plurality of vertical deflection electrodes 4 are horizontally arranged at intermediate positions of the slits 10.
The insulating substrate 12 is provided with conductors 13 and 13 'on its upper and lower surfaces. Then, the conductors 1 facing each other
A vertical deflection voltage is applied between 3 and 13 'to vertically deflect the electron beam. In this embodiment, a pair of conductors 1
An electron beam from one line cathode 2 is vertically deflected by 3, 13 'to a position for 16 lines. Then, the 16 vertical deflection electrodes 4 form 15 pairs of conductors corresponding to the 15 line cathodes 2, respectively.
The electron beam is deflected so as to draw 240 horizontal lines. Next, the control electrode 5 is composed of a conductive plate 15 each having a slit 14 which is long in the vertical direction, and a plurality of the control electrodes 5 are arranged in parallel in the horizontal direction at a predetermined interval. 18 in this example
Zero control electrode conductive plates 15-1 to 15-n are provided. (In the figure, only 9 electrodes are shown.) This control electrode 5
Respectively take out the electron beam by dividing it into two picture elements in the horizontal direction, and control the passing amount according to a video signal for displaying each picture element. Therefore, if 180 conductive plates 15-1 to 15-n for the control electrode 5 are provided, the horizontal 1
It is possible to display 360 picture elements per line. Also,
In order to display an image in color, each picture element is to be displayed with a phosphor of three colors R, G, B, and each control electrode 5 has two picture element signals of R, G, B. Are sequentially added. In addition, each of the 180 conductive plates 15-l to 15-n for the control electrode 5 has one
The video signals of 180 sets of lines (two picture elements per set) are simultaneously added, and the video of one line is displayed at one time.

The horizontal focusing electrode 6 is composed of a conductive plate 17 having a plurality of vertically long (180) slits 16 facing the slits 14 of the control electrode 5, and the electrons for each picture element divided in the horizontal direction. Each of the beams is horizontally focused into a narrow electron beam.

The horizontal deflection electrode 7 is composed of a plurality of conductive plates 18 and 18 'vertically arranged on both sides of the slit 16, and each of the electrodes 18 and 18' is used for horizontal deflection in six stages. A voltage is applied to deflect the electron beam for each picture element in the horizontal direction, and two sets of R, G, and
The phosphors of B are sequentially irradiated to emit light. The tendency range is the width of two picture elements for each electron beam in this embodiment.

The accelerating electrode 8 is composed of a plurality of conductive plates 19 horizontally provided at the same position as the vertical deflection electrode 4, and accelerates the electron beam so that the electron beam collides with the screen 9 with sufficient energy.

The screen 9 is constructed by applying a phosphor 20 that is emitted by the irradiation of an electron beam to the back surface of the glass plate 21 and adding a metal back layer (not shown). The phosphor 20 is provided for one slit 14 of the control electrode 5, that is, for each electron beam divided in the horizontal direction.
Two pairs of R, G, and B phosphors of three colors are provided, and are applied in stripes in the vertical direction. In FIG. 2, broken lines drawn on the screen 9 indicate vertical divisions corresponding to the plurality of line cathodes 2 and two-dot chain lines correspond to the plurality of control electrodes 5, respectively. Shows the horizontal division. 1 divided by both
As shown in an enlarged view in FIG. 6, two compartments each have two picture element R, G, and B phosphors 20 in the horizontal direction and one in the vertical direction.
It has a width of 6 lines. The size of one section is
For example, the horizontal direction is 1 mm and the vertical direction is 9 mm.

It should be noted that, in FIG. 5, the length in the horizontal direction is greatly enlarged with respect to the vertical direction for the sake of clarity.

Further, in this example, only one pair of R, G, and B phosphors 20 for two picture elements is provided for one control electrode 5, that is, one electron beam. Alternatively, three or more picture elements may be provided, and in that case, the R, G, B video signals for one picture element or three or more picture elements are sequentially added to the control electrode 5 and horizontal deflection is performed in synchronization therewith. Is done.

FIG. 3 shows a deflection circuit for the above-mentioned conventional image display device. Further, FIGS. 4A and 4B show a part of the deflection waveform at each time point (when the OP amplifier is output and when the amplifier is output). The operation will be described below with reference to FIGS. 3 and 4.

The image display device is composed of 240 lines per field, and the vertical deflection data corresponding to each of the 240 lines is stored in the memory 31.
The memory address corresponding to each line is read out at a proper time by direct memory access (DMA), and the DA converter 32
Is converted into a vertical deflection signal by the OP amplifier 33 and the amplifier 34.
Vertical deflection is performed via.

This situation will now be described by taking as an example the case where four-stage deflection waveforms are created as shown in FIGS. 4A and 4B. The deflection data represented by 1 byte is the staircase of the deflection waveform (1S in the figure). ~
4S). For example, 1S is 4φh, 2S is 6φh, 3S is A
φh, 4S correspond like Cφh. Therefore, when changing the magnitude of the amplitude, an amplitude adjusting variable resistor 35 shown in the drawing is used.

Problems to be Solved by the Invention However, in the above-mentioned configuration, since the semi-fixed resistor is used as the amplitude adjusting volume 35, the temperature characteristics and reliability are not sufficient, and highly accurate vertical deflection can be performed. There was a problem that it could not be done.

In view of the above problems, the present invention aims to provide a deflection circuit for an image display device, which is capable of highly accurate vertical deflection without temperature fluctuation.

Means for Solving the Problems In order to solve the above problems, the image display device of the present invention uses all the semi-fixed resistances as fixed resistances to improve temperature characteristics and reliability and enable highly accurate vertical deflection. It was done. Further, in order to change the magnitude of vertical deflection, the vertical deflection data in the memory is changed by a dedicated software to operate.

Action The action of this means is as follows.

Since a semi-fixed resistor is not used in the circuit during normal deflection, deflection can be performed with higher temperature characteristics and higher reliability than conventional deflection circuits. Further, since changing the amplitude is performed digitally via a computer, it can be performed even by an unskilled person.

Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

In FIGS. 1 and 2, 36 is an amplifier with a fixed amplification factor excluding the semi-fixed resistor, and 37 and 38 are fixed resistors. The other blocks are the same as in FIG.

Here, the operation when changing the amplitude of the waveform will be described on the assumption that each step of the four-stage deflection waveform corresponds to 4φh, 6φh, Aφh, Cφh of digital data, as shown in FIG. At this time, assuming that the amplitude of the deflection waveform at the time of output of the OP amplifier 33 is doubled, 4φh of the first stage is φh, 6φh of the second stage is 5φh, and Aφh of the third stage is Bh.
The digital data is changed by changing φh and Cφh of the fourth stage to Fφh.

This also doubles the amplitude of the deflection waveform (FIG. 2b) of the output of amplifier 36. As described above, the amplitude of the deflection waveform can be arbitrarily changed as in the conventional case, and high reliability can be obtained.

As described above, according to the present invention, the amplification factor of the amplifier is fixed, and the digital data included in each scanning line on the memory in the device is operated by the signal from outside the image display device to obtain the vertical deflection waveform. In order to change the amount of deflection, means for detecting the amount of deflection, deflection control software, etc. are provided on the manufacturing line of the image display device, and the vertical deflection data can be adjusted and stored for each image display device on the manufacturing line. Reduction of the number of parts of the device,
It has a special effect in terms of manufacturing cost, reliability, and productivity.

[Brief description of drawings]

FIG. 1 is a block diagram of a deflection circuit of an image display device according to an embodiment of the present invention, FIGS. 2a and 2b are waveform diagrams for explaining the operation, and FIG. 3 is a block diagram of a conventional vertical deflection circuit. ,
4A and 4B are waveform diagrams for explaining the operation, FIG. 5 is an exploded perspective view of the image display device, and FIG. 6 is an enlarged front view of the screen surface thereof. 31 …… Memory, 32 …… D / A converter, 33 …… OP amplifier, 36
……amplifier.

Claims (1)

[Claims] 1. A plurality of line cathodes constituting an electron beam source,
A focusing electrode for focusing the electron beam from the linear cathode,
Deflection electrodes that deflect the electron beam in the vertical and horizontal directions, a screen that emits light when the electron beam is irradiated, and an electron that controls the amount of the electron beam by a television signal to control the brightness on the screen. A beam control electrode and a deflection circuit for driving the vertical deflection electrode for the electron beam are provided, and the deflection circuit fixes the amplification factor of the amplifier when the digital data is D-A converted to obtain the vertical deflection waveform. An image display device characterized in that a vertical deflection waveform is obtained by changing and storing digital data by a control signal from the outside.