JPH03113977A - Television receiver - Google Patents

Abstract

PURPOSE:To attain interlace display without switching a horizontal deflection frequency in the case of display of a still picture by providing a vertical deflection switching means so as to switch an electron beam twice each in one and same line. CONSTITUTION:When a detection circuit 21 decides a picture not to be a still picture, a connection switch 19 is opened, a deflection signal Svo is fed to a vertical deflection coil 20 and a color picture of noninterlace display is obtained on a picture tube 11. On the other hand, the detection circuit 21 decides the picture to be a still picture, the connection switch 19 is closed and a signal S'vo added with the deflection signal Svo is fed to the vertical deflection coil 20. Thus, two scanning lines by a same signal are formed on a same position in the noninterlace display through the double scanning of the electron beam on to the same line and a color picture of the interlace display is equivalently obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a television receiver suitable for application to a television receiver constituting a large-area video signal display device such as a projector.

[Background technology and its problems]

Image display using the interlaced method has 525 scanning lines.
In the case of a book, one field is made up of 262.5 books, and screen flicker is suppressed by sending this at 60 Hz. Further, in order to obtain extra vertical resolution, the next field after a certain field is scanned with a shift of the scanning line interval.

In this case, even if macroscopically the scanning rate is 60 frames per second, microscopically one scanning line lights up every 1/30 seconds, and the display period is 1730 seconds. Therefore, the light emitted from one scanning line is visually perceived as flicker, which impedes improvement in image quality.

Non-interlaced display is known as a means of eliminating this flicker and obtaining high-quality images. For example, an interlaced video signal is converted into a non-interlaced video signal with twice the horizontal frequency, and this is supplied to a picture tube, where the horizontal deflection frequency is doubled to display non-interlaced images. It is something.

In this way, various simple methods have been proposed that use inexpensive line memory instead of expensive large-capacity memory to convert an interlaced video signal into a non-interlaced video signal with twice the horizontal frequency. ing. In this case, the simplest method is to sequentially write each scanning line signal of an interlaced video signal into the line memory, and then read each scanning line signal twice at twice the writing speed. be. That is, each scanning line signal of the interlaced system is written as a, b, c, etc. in the line memory, and then a, a
, b, b, c, c, . . .

A television receiver that performs non-interlace display using a non-interlace video signal with twice the horizontal frequency converted by such a method is sufficiently effective in displaying moving images or characters. However, when displaying a still, detailed image, the above-mentioned scanning line flicker is eliminated, but since two scanning lines are formed with the same signal in succession, the vertical resolution decreases and the image quality actually deteriorates. May deteriorate.

Conventionally, it has been proposed to return to the original interlaced display when displaying such still images, but this requires switching the horizontal deflection frequency depending on the video signal, which is expensive and Technically, it was difficult to obtain the desired performance.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to propose a television receiver that can perform interlaced display without switching the horizontal deflection frequency when displaying still images, for example.

[Summary of the invention]

In order to achieve the above object, the present invention is provided with a vertical deflection switching means, and this switching means allows the electron beam to move two times along the same line.
This feature is characterized in that the scanning is switched in such a way that scanning is performed in increments.

(Example) Hereinafter, an example of the present invention will be described with reference to FIG.

In the figure, (1) is an antenna, (2) is a tuner,
(3) is an intermediate frequency amplifier, and (4) is a video detection circuit.

An interlaced color video signal S is obtained from this detection circuit (4), and this is sent to the luminance/color separation circuit (5).
is supplied to

The luminance signal Y obtained from the separation circuit (5) is supplied to the matrix circuit (6). Further, the color signal C obtained from the separation circuit (5) is supplied to the color demodulation circuit (7), from which a red difference signal R-Y and a blue difference signal B-Y are obtained, and each is supplied to the matrix circuit (6). be done. Red, green, and blue primary color signals R2C and B are obtained from the matrix circuit (6) and supplied to the double speed conversion circuit (8), respectively.

In this conversion circuit (8), from the signal R, the horizontal frequency that is continuous twice with the period of the signal -H of each scanning line is 2.
A doubled signal R2 is obtained, and this is transferred to the selector switch (9
R)! 7) Supplied to the cathode KR of the color picture tube (1st construction) via the a side and the drive circuit (10). Similarly, in this conversion circuit (8), the signals G, B
A signal G2B2 with the horizontal frequency doubled is obtained,
The light is supplied to the cathodes Kc and Km of the picture tube (11) via the a side of the changeover switches <9G) and (9B) and the drive circuit (10), respectively.

Further, the video signal S obtained from the detection circuit (4) is supplied to the synchronization separation circuit (12). This separation circuit (12)
The horizontal synchronizing signal PH obtained is doubled by a multiplier (13) and then supplied to a horizontal deflection circuit (14).

Then, from this deflection circuit (14), a horizontal deflection coil (1
5) is supplied with a deflection signal S0° having a normal frequency of 2 (B) as shown in FIG. 2B.

In addition, the vertical 11 signal P obtained from the separation circuit (12)
v is supplied to a vertical deflection circuit (16). A vertical deflection signal S, as shown by the solid line in FIG. 2, is generated from this deflection circuit (16). is supplied to the adder (17).

Further, the doubled signal of the horizontal synchronizing signal P from the multiplier (13) is supplied to the auxiliary deflection signal generation circuit (18), and from this generation circuit (18), as shown in FIG. 2C, An auxiliary deflection signal SVC that reaches a predetermined level every -H is obtained. This level is the level at which the beam scanning position can be shifted by l -scanning line interval. This auxiliary deflection signal SVC is supplied to an adder (17) via a connection switch (19). And adder (17)
The summed signal from the vertical deflection coil (20) is supplied to the vertical deflection coil (20).

Further, in FIG. 1, (21) is a motion detection circuit,
This is to determine whether the image is a still image.

A luminance signal Y is supplied to this detection circuit (21) from a separation circuit (5). This determination is made, for example, by comparing the luminance signal Y of a certain field and several fields later at several points on the screen.

Judgment signal S from this detection circuit (21). is the control circuit (
22), and this control circuit (22) controls on/off of the above-mentioned connection switch (19).

In this case, the connection switch (19) is turned on when it is determined that the image is a still image. The connection switch (19) is turned on and off, for example, at the beginning of each field.

The present example is configured as described above, and when the detection circuit (21) determines that the image is not a still image, the connection switch (19) is turned off, so that the vertical deflection coil (20) receives the deflection signal S. (shown in solid line in Figure 2A) is supplied, and the picture tube (1
1), a non-interlaced color image is obtained as shown in FIG. 3A.

On the other hand, when the detection circuit (21) determines that it is a still image, the connection switch (19) is turned on, so the vertical deflection coil (20) receives the deflection signal Sv, (solid line in Figure 2). A signal S'vo (shown by a broken line in FIG. 2A) is supplied which is the sum of the auxiliary deflection signal 5vc (shown in FIG. 2C) to the auxiliary deflection signal 5vc (shown in FIG. 2C). Therefore, as shown in FIG. 3B, the electron beam scans the same line twice, and two scanning lines (shown by a solid line and a broken line) with the same signal in a non-interlace display are formed at the same position, and the equivalent An interlaced color image is obtained.

In FIG. 1, (23R), (23G) and (23B) are input terminals for external R, G and B signals.

For example, a signal from a character decoder, a high-definition television receiver, or, in the case of a still image, a signal formed by a field interpolation method using a field memory is supplied. These R, G, and B signals are supplied to the drive circuit (10) through the b sides of the changeover switches (9R), (9G), and (9B), respectively, and the picture tube (11) receives a color image based on these signals. is displayed. In this case, the R, G, and B signals supplied to the terminals (23R), (23G), and (23B) are supplied to the discrimination circuit (24), and when a signal exists, the discrimination output of the discrimination circuit (24) connects the terminals. The switch (19) is turned off.

As described above, according to this example, when displaying a still image, interlaced display can be performed without switching the horizontal deflection frequency.

In the above-described embodiment, the connection switch (19) is automatically turned on and off, but the viewer may also be able to control it manually.

Further, in the above embodiment, the auxiliary deflection signal SVC is added to the deflection signal SVO, but a vertical sub-deflection coil is newly provided and the auxiliary deflection signal SVC is supplied to it to perform the same operation. Good too.

〔Effect of the invention〕

According to the present invention described above, for example, in the case of displaying a still image, interlaced display can be easily achieved by simply switching the deflection switching means without switching the horizontal deflection frequency. Therefore, no inconvenience occurs due to switching of the horizontal deflection frequency.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIGS. 2 and 3 are diagrams for explaining the same. (8) is a double speed conversion circuit, (11) is a color picture tube, (1
4) is a horizontal deflection circuit, (15) is a horizontal deflection coil, (1
6) is a vertical deflection circuit, (18) is an auxiliary deflection signal generation circuit, (19) is a connection switch, and (20) is a vertical deflection coil.

Claims (1)

[Claims] In a television receiver in which non-interlaced horizontal deflection is performed at twice the normal deflection frequency,
1. A television receiver comprising vertical deflection switching means for switching the electron beam so that it scans the same line twice each time.