JPH05122633A - Television receiver - Google Patents

Abstract

PURPOSE:To reduce the generation of uneven luminance by providing a means temporarily emitting light at the display position of an image for a non-image part generated when a video image having an aspect ratio of 4:3 is outputted by a wide-aspect receiver. CONSTITUTION:A pilot signal discrimination circuit 6 extracting a pilot signal from a television signal and discriminating it, a counter 8 counting the output time of a video signal having an aspect ratio of 4:3 from the pilot signal, and a display position control circuit 9 controlling the display position of the image having the aspect ratio of 4:3 corresponding to output time, are provided. A light emission control means temporarily emitting light at the non-image part of a Braun tube generated when the power supply of the system is turned off is also provided. In such a case, the light is emitted at the non-image part when the image having the aspect ratio of 4:3 is outputted for a prescribed period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver for displaying a wide aspect image.

[0002]

2. Description of the Related Art An auxiliary signal is added to a video signal while maintaining compatibility with a video signal having an aspect ratio of 4: 3 in the current NTSC system to display a high quality wide aspect video with an aspect ratio of 16: 9. Several television systems have been proposed in the past. One of the letterbox methods will be described with reference to FIG.

The aspect ratio shown in FIG. 6 (a) is 16: 9.
When a wide aspect ratio video signal of is displayed on a receiver with a current aspect ratio of 4: 3, it is reduced to 3/4 times as shown in FIG. 6 (b) and a main image B is displayed at the center of the screen. Auxiliary signals for projection and wide aspect are transmitted by utilizing the non-image portions A and C at the top and bottom of the screen indicated by the diagonal lines in the figure. On the other hand, as shown in FIG. 6C, in the wide aspect receiver, the main image B is magnified 4/3 times, and the auxiliary signals transmitted by being superimposed on the non-image areas A and C are used to improve the image quality. A wide aspect image with an aspect ratio of 16: 9 is reproduced and displayed.

[0004]

However, in a wide aspect receiver having an aspect ratio of 16: 9, as shown in FIG.
As shown in (a), when an image with an aspect ratio of 4: 3 that uses only a part of the cathode ray tube is always fixed and displayed in the central portion E of the screen, and with an aspect ratio of 16: 9 that uses the entire cathode ray tube. In the case of displaying a video signal (not limited to a letterbox signal), the CRT is more frequently used in the central portion E than in the left and right sides of the screen shown in D and F of FIG. A screen burn difference occurs between the left and right D and F and the central portion E. When the brightness unevenness due to the screen burn-in phenomenon occurs in the CRT as described above, there is a problem in that when a video signal utilizing the entire CRT is displayed, the brightness unevenness occurs in the image and the image quality deteriorates.

[0005]

In order to solve the above problems, the present invention maintains compatibility with the NTSC color television broadcasting system, adds an image quality enhancement auxiliary signal on the transmission side, and In a television receiver capable of receiving a television signal on which a pilot signal for determining whether the aspect ratio is 4: 3 or a wide aspect is superimposed and displaying a high quality wide aspect image, the pilot signal From the television signal, a counting means for counting the projection time of a video signal having an aspect ratio of 4: 3 from the pilot signal, and an aspect ratio of 4: depending on the projection time. Display position control means for controlling the display position of the image of 3 is provided to prevent the screen burn-in phenomenon of the CRT. Configured to reduce that unevenness in brightness.

In addition, in accordance with the projection time of the video signal having the aspect ratio of 4: 3 counted by the counting means, the picture of the cathode ray tube which is generated when the image having the aspect ratio of 4: 3 is projected when the system is powered off. A configuration is provided in which a light emission control unit that causes a portion to emit light at one time is provided.

Further, a pilot signal for selecting a display position of a video signal having an aspect ratio of 4: 3 is superimposed on the television signal, and the aspect ratio is changed according to the pilot signal extracted by the pilot signal extracting means. The display position control means for controlling the display position of the 4: 3 video signal is provided.

[0008]

According to the above construction, the pilot signal superimposed on the transmitted video signal is detected, the aspect ratio and the broadcast format of the transmitted video signal are discriminated, and the pilot signal is transmitted. When the video signal present is a video signal using a part of the cathode ray tube, the projection time of the video signal is counted.

Then, the display position of the projected image by the video signal is controlled according to the count value, the cathode ray tube is partially lit according to the count value when the power is turned off, and further the pilot is operated. A signal for selecting the display position of the video signal that uses a part of the cathode ray tube is superimposed on the signal in advance, and the display position of the image displayed by the above video signal is controlled by this signal, and the brightness due to the screen burn-in phenomenon of the cathode ray tube. Reduce the occurrence of unevenness.

[0010]

Embodiments of the present invention will be described in detail with reference to FIGS. Although not shown on the transmitting side, the pilot signal Ps for notifying whether the video signal to be transmitted is a current video signal with an aspect ratio of 4: 3 or a video signal with a letterbox method or an aspect ratio of 4: 3 A television signal in which a pilot signal Pa for selecting the display position of the video signal is superimposed, for example, within a vertical blanking period is transmitted. First, referring to FIG. 1, FIG. 4 and FIG.
An example will be described.

FIG. 1 is a block diagram of a first embodiment for reducing the uneven brightness of the CRT when the above television signal is received and an image is displayed on a part of the CRT. In the wide aspect receiver, the television signal input from the video input terminal 1 is supplied to the A / D conversion circuit 2, the sync separation circuit 3, and the clock generation circuit 4. The clock generation circuit 4 is locked to the burst signal of the video signal and has a frequency 4 times the subcarrier frequency fsc, 4fsc (14.318 MH).
The clock z) is generated and supplied to each circuit as a system clock.

The sync separation circuit 3 separates the sync signal from the video signal, supplies the sync signal to the gate circuit 5, and the gate circuit 5 uses the sync signal within the vertical blanking period of the television signal. The superposed pilot signal Ps is supplied to the sampling determination circuit 6. The discriminating circuit 6 uses the pilot signal Ps sent from the gate circuit 5 so that the aspect ratio of the transmitted video signal is 16: 9.
In the case of the letter box method, the discrimination signal Pj is set to L level, and when the current aspect ratio is 4: 3, the discrimination signal Pj is set to H level and the wide aspect processing circuit 7, It is supplied to the counter circuit 8 and the display position control circuit 10.

The counter circuit 8 does not count when the discrimination signal Pj supplied from the discrimination circuit 6 is at L level,
Counting is performed at the H level, and when a certain count value (for example, 24 hours) is reached, the counter pulse Cu is supplied to the display position control signal generating circuit 9. The display position control signal generation circuit 9 detects the counter pulse Cu and holds the state. The display position control signal generation circuit 9 supplies the V supplied from the power-off detection signal input terminal 12 so that the image display position does not change during image display.
When the O signal becomes L level, the control signal DS is controlled by the detected counter pulse Cu so that the position of the display image is on the left side of the screen as shown in FIG. 4B, for example. To the display position control circuit 10.

Similarly, the control signal DS is
For example, from the control signal DC for controlling the display position of the display image so that it is sequentially located in the center of the screen as shown in FIG. 4 (a), it is set to the right side of the screen as shown in FIG. 4 (c). The control signal DR for controlling the control signal is switched to the control signal DL again.

The display position control signal generation circuit 9 supplies the counter circuit 8 with a reset signal RE for resetting the count of the counter circuit 8 when the switching of the control signal DS is completed. The counter circuit 8 resets the count value by the reset signal RE. The counter circuit 8 holds the counted value even when the system power is not supplied.

On the other hand, the A / D conversion circuit 2 samples the input analog video signal at 4 fsc, digitizes it, and supplies it to the wide aspect processing circuit 7. When the discrimination signal Pj supplied from the discrimination circuit 6 is at L level indicating that it is a wide aspect video signal, the wide aspect processing circuit 7 enlarges the main screen by 4/3 times as shown in FIG. 6C. The image is enlarged, the image quality is improved by using the auxiliary signal multiplexed in the non-image portion, and the image is supplied to the display position control circuit 10. When the discrimination signal Pj is at the H level, the video signal is a current video signal having an aspect ratio of 4: 3, and thus compressed to 3/4 times in the horizontal direction and supplied to the display position control circuit 10.

The display position control circuit 10 has an aspect ratio of 4: 3 when the display position control signal DS supplied from the display position control signal generation circuit 9 is the control signal DL for displaying the screen on the left side.
When the control signal DC is such that the screen of FIG. 4 is moved to the left side as shown in FIG. 4 (b) and the screen is displayed at the center, the screen is displayed at the center as shown in FIG. 4 (a) and the screen is displayed on the right side. When the control signal DR to be displayed on
As shown in FIG. 4C, a video signal that causes the screen to be displayed on the right side is output.

Further, when the discrimination signal Pj supplied from the discrimination circuit 6 is at L level, the video signal is a letterbox type wide aspect ratio video signal, so that the display position control signal DS shown in FIG. As shown in c), it is supplied to the D / A conversion circuit 11 in the next stage as a normal wide aspect video signal displayed on the entire screen.
The D / A conversion circuit 11 includes the display position control circuit 10
The supplied digital signal is converted to an analog signal and output from the video signal output terminal 13. When the video signal has a wide aspect ratio, it is used as the image of the entire screen, and when the video signal has an aspect ratio of 4: 3, the image is output. Are displayed in the center of the left and right at regular intervals. Therefore, it is possible to reduce a partial difference in screen burning of the cathode ray tube.

Next, a second embodiment of the present invention will be described with reference to FIGS.
And FIG. 6 will be described. In FIG. 2, parts corresponding to those of the first embodiment shown in FIG. FIG. 2 is a block diagram of the second embodiment of the present invention. The discrimination signal Pj from the discrimination circuit 6 is supplied to the wide aspect processing circuit 7 and the counter circuit 8, and the counter circuit 8 supplies the discrimination signal Pj supplied from the discrimination circuit 6.
Is not at the L level, counting is performed at the H level, and the counter pulse Cu is supplied to the flash signal generating circuit 1 at a certain count value, for example, 24 hours.
Supply to 6.

The flash signal generation circuit 16 holds that the counter pulse Cu has been supplied, and the signal VO input from the power-off detection signal input terminal 12 is L level.
When the level is reached, that is, when the power is turned off,
A flash signal as shown in FIG. 5B is generated for a fixed time (for example, 1 second) and supplied to the selector circuit 17. However, at this time, if the power of the system is turned off by, for example, a switch and the like, and the power supply voltage of the system is turned off after a certain period of time, the system remains constant even after VO becomes L level. Works for hours.

The flash signal generated by the flash signal generating circuit 16 is generated by a wide aspect receiver when a video signal having an aspect ratio of 4: 3 is projected. It is the video signal shown in FIG. 5B that causes only the image portions D and F to emit light. Therefore, the screen burn is forcibly caused only in the non-image portions D and F shown by the diagonal lines in FIG.
The screen is burned to the same degree as the image display portion E of.

Further, the flash signal generating circuit 16 outputs a reset pulse RE for resetting the count value of the counter circuit 8 after the flash signal is generated.
To reset the count value of the counter circuit 8. The count value of the counter circuit 8 is held even when the system power is not supplied.

On the other hand, the A / D conversion circuit 2 samples the input analog video signal at 4 fsc, digitizes it, and supplies it to the wide aspect processing circuit 7. When the discrimination signal Pj supplied from the discrimination circuit 6 is at the L level, the wide aspect processing circuit 7 expands the main screen by 4/3 times as shown in FIG. 6C, and is multiplexed in the non-image portion. When the discrimination signal Pj is at the H level, the image signal is a current image signal having an aspect ratio of 4: 3, so that the image quality is improved by using the auxiliary signal. It is compressed four times and supplied to the selector circuit 17.

The selector circuit 17 selects the wide aspect processing circuit 7 side when the signal VO input from the power-off detection signal input terminal 12 is at the H level, and when the signal VO is at the L level, inputs the flash signal generation circuit 16 to the input. By selecting to the side, the flash signal can be
It is supplied to the A conversion circuit 11. The D / A conversion circuit 11 converts the digital signal supplied from the selector circuit 17 into an analog signal and outputs the analog signal to the video signal output terminal 13, so that the D / A conversion circuit 11 forcibly outputs the video signal to the video signal output terminal 13. It is possible to make the light emitting part emit light, and it is possible to reduce the difference in screen burning between the central part and the side part of the cathode ray tube.

Next, a third embodiment of the present invention will be described with reference to FIGS.
And FIG. 6 will be described. In FIG. 3, parts corresponding to those of the first and second embodiments shown in FIGS. 1 and 2 are given the same reference numerals and the description thereof will be omitted. FIG. 3 is a block diagram of the third embodiment of the present invention. The gate circuit 5 uses the sync signal supplied from the sync separation circuit 3 to have an aspect ratio of 4: superimposed in the vertical blanking period of the television signal.
The pilot signal Pa having the display position information of the image No. 3 is extracted and supplied to the display position control signal generation circuit 14. The display position control signal generation circuit 14 determines the display position of an image having an aspect ratio of 4: 3 based on the value of the pilot signal Pa supplied from the gate circuit 5.

That is, the pilot signal Pa is previously set to, for example, 2
It is a bit digital signal, "00" is a letterbox signal, "01" is a signal for displaying an image with an aspect ratio of 4: 3 in the center, and "10" is an image with an aspect ratio of 4: 3. The signal to be displayed, “11”, may be defined as the signal to display the image having the aspect ratio of 4: 3 by shifting it to the right. In this way, the display position control signal generation circuit 14 causes the control signal DS to be displayed on the entire display screen as shown in FIG. 6C when the pilot signal Pa is "00", as shown in FIG. 6C. When the control signal DW is "01", it becomes the control signal DC for displaying an image having an aspect ratio of 4: 3 in the central portion of the display screen as shown in FIG. 4A, and is "10" or "11". When it is ",
(B) or a control signal DL to be displayed on the left or right side of the display screen as shown in FIG. 4 (c)
Alternatively, it becomes DR and is supplied to the wide aspect processing circuit 7 and the display position control circuit 15.

On the other hand, the A / D conversion circuit 2 samples the input analog video signal at 4 fsc, digitizes it, and supplies it to the wide aspect processing circuit 7. When the control signal DS supplied from the display position control signal generation circuit 14 is the control signals DL, DC and DR, the wide aspect processing circuit 7 is a video signal having an aspect ratio of 4: 3, so that the horizontal direction is 3/4. It is compressed twice, and the control signal DC is the above-mentioned control signal D.
In the case of W, the main screen is expanded to 4/3 times as shown in FIG. 6C, the image quality is improved by using the auxiliary signal multiplexed in the non-image part, and the result is supplied to the display position control circuit 15. ..

The display position control circuit 15 is shown in FIG. 4 when the control signal DS supplied from the display position control signal generation circuit 14 is the control signal DL.
As shown in FIG. 4B, the screen having an aspect ratio of 4: 3 is shifted to the left, when the control signal DC is set to the center as shown in FIG. 4A, and when the control signal DR is set to FIG.
As shown in FIG. 6C, when the video signal is shifted to the right, and when the control signal DS is the control signal DW, the video signal has a wide aspect ratio. Therefore, as shown in FIG. 6C, a video signal having an aspect ratio of 16: 9. As the next D / A
It is supplied to the conversion circuit 11. The D / A conversion circuit 11 converts a digital signal into an analog signal, outputs a video signal whose display position is controlled from the output terminal 13, and distributes and displays an image having an aspect ratio of 4: 3 to the left and right centers. Therefore,
It is possible to reduce the partial difference in screen burning of the cathode ray tube.

[0029]

As described above, the present invention has the above-mentioned configuration, and the non-image portion which is generated when a video having an aspect ratio of 4: 3 is projected on a wide aspect receiver is forced to change the display position of the image or to force it. It is possible to reduce the occurrence of uneven brightness due to screen burning by temporarily emitting light.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of another embodiment of the present invention.

FIG. 3 is a block diagram of still another embodiment of the present invention.

FIG. 4 is an operation explanatory diagram of FIGS. 1 and 3;

FIG. 5 is an operation explanatory diagram of FIG. 3;

6 is an operation explanatory diagram of FIGS. 1, 2, and 3. FIG.

[Explanation of symbols]

 5 Gate 6 Discrimination circuit 8 Counter 9 Display position control circuit 16 Flash signal generation circuit 17 Selector

Claims (3)

[Claims] Claims: 1. While maintaining compatibility with the NTSC color television broadcasting system, adding a high image quality auxiliary signal on the transmitting side, and determining whether the aspect ratio of the video signal to be transmitted is 4: 3 or wide aspect ratio. In a television receiver capable of receiving a television signal on which a pilot signal to be discriminated is superimposed and displaying a high quality wide aspect image, pilot signal discriminating means for discriminating the pilot signal from the television signal, and Counting means for counting a projection time of a video signal having an aspect ratio of 4: 3 from a pilot signal, and display position control means for controlling a display position of an image having an aspect ratio of 4: 3 according to the projection time. It is provided to reduce uneven brightness due to screen burn-in phenomenon of a cathode ray tube. Vision receiver. 2. An image forming auxiliary signal is added on the transmitting side while maintaining compatibility with the NTSC color television broadcasting system, and whether the aspect ratio of the video signal to be transmitted is 4: 3 or wide aspect ratio. In a television receiver capable of receiving a television signal on which a pilot signal to be discriminated is superimposed and displaying a high-quality wide aspect image, pilot signal discriminating means for discriminating the pilot signal from the television signal, and Counting means for counting the projection time of the video signal having an aspect ratio of 4: 3 from the pilot signal, and the aspect ratio of 4: 3 when the power of the system is turned off according to the projection time.
A television receiver characterized in that it is provided with a light emission control means for temporarily emitting the non-image part of the CRT when the image is displayed, so as to reduce the uneven brightness due to the screen burn-in phenomenon of the CRT. 3. A compatibility with the NTSC color television broadcasting system is maintained, a high image quality auxiliary signal is added on the transmitting side, and a pilot signal for selecting a display position of a video signal with an aspect ratio of 4: 3 is superimposed. In a television receiver capable of receiving a television signal and displaying a high-quality wide aspect image, a pilot signal extracting means for extracting the pilot signal from the television signal, and an aspect ratio corresponding to the pilot signal A television receiver characterized in that display position control means for controlling a display position of a 4: 3 video signal is provided to reduce uneven brightness due to a screen burn-in phenomenon of a cathode ray tube.