JPS5890873A - Television receiver - Google Patents

Abstract

PURPOSE:To prevent remarkable scanning lines on a screen with less change without deteriorating the vertical resolution, by using two scanning lines normally, and using one for a part where vertical change is produced in a video signal. CONSTITUTION:A video signal from a terminal 1 is applied to the 1st electron gun 31 of a cathode ray tube 3 through an amplifier 2 and to the 2nd electron gun 32 through a delay circuit 4 and an amplifier 5, allowing to draw scanning lines adjacent to two beam spots. Further, a difference between a video signal and that before one horizontal period is obtained at a differential amplifier 6 to pick up the vertical change. When this change is larger than a prescribed value, the supply of current to a coil 33 is stopped so as to draw the same scanning line for the two beam spots. Thus, without deteriorating the resolution toward vertical direction, the flickering due to scanning lines can be prevented when the change on a screen is less.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to improve the vertical resolution of images in the current television system.

In the 11-line television system, a scanning method called interlace is used. In other words, one image (
frame) is transmitted in two vertical scans (fields), and this is done in order to increase the number of scanning lines as much as possible without causing flicker to the viewer's eyes in a limited frequency band. It was well thought out.

However, when actually transmitting using the interlace method, there is no problem when the screen changes frequently.

When a smooth screen with few changes is displayed, K flicker (disturbance) becomes noticeable because adjacent scanning lines blink alternately at the field frequency.

Therefore, it has been considered to make the scanning beam spot vertically elongated and increase the interval between the scanning lines by 5 to make the scanning lines less noticeable, but this would degrade the vertical resolution of the image.

In view of these points, the present invention eliminates the above-mentioned interference and prevents the vertical resolution from deteriorating.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which the present invention is applied to a monochromatic tube used in a so-called video projector.

In the figure, (1) is a power terminal, to which a video signal of red, green, or blue is supplied. This input terminal (
The signal from 1) passes through the amplifier (2) to the cathode ray tube (8).
The second electron is supplied to the first electron gun 01) through a delay circuit (4) and an amplifier (5) equal to the scanning delay time T which corresponds to the spacing of the tending positions on the screen, which will be described later. Supplied to the gun (to).

In addition, the signal from the input terminal (1) is supplied to the differential amplifier (6), and is also supplied to the amplifier (6) through the delay circuit (7) for one horizontal period, and the difference between the signal from one horizontal period ago,
That is, the amount of change in the video signal in the vertical direction is extracted.

This signal is supplied to the scanning interval control circuit a through the rectifier circuit (8) and the square circuit (9), and this control circuit
A control current is supplied to a coil (to) provided at the neck of the pole ray tube (3).

In this cathode ray tube (3), the electron guns 6υ and Q are arranged horizontally, and these electron guns C1),
The electron beams from (2) are emitted so as to cross horizontally within the coil. Here, the electron beams are crossed in the coil (to), so when a current is passed through coil 03 to generate a magnetic field, a force acts on the horizontal vector of the electron beams, for example, The electron beam heading to the right is bent upward, and the electron beam heading left is bent downward.

Furthermore, these electron beams are made parallel by an auxiliary electrode and deflected vertically and horizontally by a deflection coil.

Therefore, on the image, when no current is flowing through the coil (to), a beam spot is formed as indicated by the broken line in Figure 2, and by passing a predetermined current through the coil &l, a beam spot is formed.
It can be moved to the position of an adjacent scanning line as shown by the solid line. In the figure, solid straight lines indicate, for example, the positions of odd-numbered field scanning lines, and broken-lined straight lines indicate the positions of even-numbered field scanning lines.

By delaying the video signal forming the subsequent beam spot by a scanning delay time of 7 minutes corresponding to the beam spot interval at this time, one image is displayed with two beam spots.

That is, adjacent scanning lines are drawn with each beam spot, and scanning lines are always drawn with each field, thereby achieving the above-mentioned disturbance-free display.

Furthermore, in this device, in the part where the vertical video signal has changed, by stopping the current supply to the illumination, the two beam spots are the same in that part, as shown in Figure 3. Starts drawing scan lines.

Therefore, the number of scanning lines becomes one in this portion, thereby preventing deterioration of vertical resolution.

This is how images are displayed, and according to the present invention, normally there are two scanning lines, and in areas where there is a vertical change in the image signal, there is only one scanning line.
KL, so in areas where smooth surfaces with little change are displayed, the scanning lines are not visible and interference is eliminated, and vertical resolution is no longer strained in areas with changes, resulting in a consistently good image. is displayed.

Note that other methods may be used to change the beam spacing.

For example, the electron guns 0υ, (to) are arranged vertically shifted by one scanning line, and the normal scanning position is different, and
At the time of change, the scanning position may be made to match by flowing Il&IK current.

In addition to bending the electron beam using the magnetic field generated by the five coils as described above, it is also possible to bend the beam using an electric field by providing an auxiliary electrode. In this case, the electron gun 61), (to)
are arranged vertically.

Furthermore, it is also possible to arrange six beams in two rows of three beams and apply it to a color receiver.

Alternatively, as shown in FIG. 4, the normal scanning positions (solid lines) may be separated by at least one scanning line, and when changing, they may be brought closer to each other by one scanning line and the positions indicated by the dashed dotted lines may be scanned together.

In this case, it is possible to prevent the luminescence of the phosphor from becoming saturated due to the proximity of the two beam spots.

Furthermore, it is better not to make the change in the control signal from the scan interval control circuit member steep, but to make it change gradually as shown in FIG.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an example of the present invention, and FIGS. 2 to 4 are diagrams for explaining the same. (1) is the input terminal, (3) is the cathode ray tube, (4), (7)
is a delay circuit, (l is a scanning interval control circuit, aη, (2)
is the electron gun, and (to) is the coil.

Claims (1)

[Claims] An interlaced video signal is supplied to the first and second electron beam generation sources, scanning is performed simultaneously with these electron beams, and the vertical interval of these electron beams is set to the vertical interval of the video signal. A television receiver characterized in that it changes in response to changes.