JPH0698272A - Television receiver - Google Patents

Abstract

PURPOSE:To prevent a short time screen display hard to recognize or to keep screen from too long a display by displaying teletex information to be displayed on a screen when a power source is applied for a prescribed time setting a time when the current value of a cathode reaches a certain value as reference. CONSTITUTION:A microcomputer 5 drives a CRT 12 by a reference signal outputted after the power source is applied, and detects whether or not a cathode current Ik running at that time exceeds a certain value. The microcomputer discriminates whether or not a video is being muted at present when the cathode current reaches the certain value, and when it is being muted, muting is cancelled, and a value set on a drawing display request flag is detected. At this time, a value 0 if set on the flag, and the display time of the teletex information is set on a counter 6. Drawing display by an on-screen display 11 and the count- down of the counter 6 are performed until residual display time shows zero second, and the drawing display is completed at a time when the residual display time shows zero second.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver, and more particularly to a television receiver capable of displaying channel selection information and the like on a screen.

[0002]

2. Description of the Related Art In recent years, most television receivers are provided with an on-screen display circuit so that information such as a selected channel can be displayed on the screen so that the user can see the current situation of the television receiver. It's becoming more convenient to figure out. The above-mentioned display means can be operated by operating the screen display keys and menu display keys provided on the operation unit or the remote commander, etc. However, regarding the display of channel information (selected channel, audio mode, etc.), the television When the power of the John receiver is turned on, based on the time of turning on the power,
Information of the channel (last channel) selected at that time is displayed for a predetermined time.

[0003]

However, some television receivers mute the image output to the CRT after the power is turned on until the beam current value of the CRT exceeds a certain value. In such a television receiver, the time until the beam current value becomes a certain value or more is different in the hot state, which is the standby state, and the cool state, in which the main switch is off.

As described above, the conventional television receiver is set so that the display time of the channel information and the like is displayed for a predetermined time with reference to the time when the power is turned on. However, in the hot state, the time for the beam current value to reach a certain value or more becomes shorter than in the cool state, so that the image is output earlier than in the cool state. Therefore, the display time may become longer or shorter depending on the state of the television receiver. Especially, when the display time becomes long, the display becomes unpleasant.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and the display time of the character / graphic information displayed on the screen when the power is turned on is fixed at a constant cathode current value. The display is configured to be displayed for a predetermined period of time when the value is equal to or greater than the value.

[0006]

Since the display time of the character / graphic information when the power is turned on is set on the basis of the time when the cathode current value exceeds a certain value, whether the initial state of the television receiver is cool or hot. Even if there is, the display time will be constant.

[0007]

Embodiments of the television receiver of the present invention will be described below. FIG. 1 is a block diagram of a television receiver of the present invention, particularly a video circuit system. In this figure, 1 is a tuner for selecting broadcast radio waves, 2 is an intermediate frequency amplifier, 3
Indicates a video processor. The video processor 3 supplies an image signal, which is an RGB signal, to the CRT 12 via the drive circuit 4, and outputs a reference signal (white balance) as described later, which is detected by the drive circuit 4 at this time. The white balance adjustment process is also performed by the cathode current Ik of the CRT 12.

Reference numeral 5 is a microcomputer for controlling the above-mentioned functional circuits, and 6 is a counter for counting the display time of the screen display, which may be provided in the microcomputer 5. Reference numeral 7 denotes an operation unit equipped with a power switch on / off key, a channel selection key, and the like, 8 denotes an infrared light receiving unit for inputting a remote control signal output from the remote commander RC, and the input remote control signal is input to the demodulation unit 9. It is input to the microcomputer 5 via the above and various signal processing and control are performed.

Reference numeral 10 is a character generator, and 11 is an on-screen display. Channel information, a menu screen, etc. are formed as character / graphic information, and the character / figure information is displayed.
The graphic information is combined with the video signal by the video processor 3 and output to the CRT 12.

The television receiver of the present invention is provided with the above-mentioned circuit blocks and the like, and when the power is turned on,
First, for example, initialization of internal data, mute of audio / video, power supply to CRT 12, and screen display request flag with value 1
Each process such as setting is performed.

Next, the outline of the white balance adjustment processing of the video processor 3 performed after the power of the television receiver is turned on will be described with reference to FIG. In this figure, (a) shows a timing waveform diagram of the video signal, and (b) shows the shape of the video signal supplied during the video period and the reference signal for white balance adjustment supplied at a predetermined position in the vertical blanking period. Shows. Further, (c) shows the cathode current Ik (RGB) detected when the reference signal is supplied, and the white balance is adjusted by this cathode current Ik (RGB).

That is, the video processor 3 inserts RGB reference signals for measuring white balance, for example, in the vertical blanking period of the video signal and outputs it to the drive circuit 4. The drive circuit 4 outputs information on the cathode current Ik (RGB) of the CRT 12 at the time of outputting the reference signal to the video processor 3, and the video processor 3 uses the information on the cathode current Ik to drive the white balance signal. Is output. Further, when it is detected that the cathode current Ik has exceeded a certain value, the detection data is output to the microcomputer 5.

The processing of the white balance signal performed by the video processor 3 described with reference to FIG. 2 is always performed not only when the power is turned on, but also thereafter.

Next, how the microcomputer 5 performs the tube surface display control when the power is turned on will be described with reference to the flowchart of FIG. The CRT 12 is driven by the reference signal output after the power is turned on, and it is detected whether or not the cathode current Ik flowing at that time is a certain value or more (S001), and this cathode current Ik is made a certain value or more. If so, it is determined whether or not the video is currently muted (S002).
(S003), the value set in the screen display request flag is detected (S004).

Normally, the value 1 is set in the screen display request flag by the above-described processing when the power is turned on. At this time, therefore, the value 0 is set in the screen display request flag (S005), and the channel information is set in the counter 6. The display time of the character / graphic information such as is set (S006).

And until the display time is 0 seconds remaining
(S007), the screen display of the character and graphic information such as channel information by the on-screen display 11 (S008) and the countdown of the counter 6 (S009), the screen display is displayed when the display time reaches 0 seconds. End (S01
0).

As described above, the television receiver of the present invention is turned on to detect whether or not the cathode current Ik has become a certain value or more, and the cathode mute is released when the cathode current becomes a certain value or more. At the same time when the image is output on the screen, the counting of the display time of the character / graphic information is started. When the display time ends due to the count-out of the counter 6, the character / graphic information is erased.

[0018]

As described above, in the television receiver of the present invention, the screen display time of the last channel when the power is turned on, the cathode current value of the CRT is detected, and the cathode current value becomes a certain value or more. , When the video mute is released, the count can be started and the video can be displayed for a predetermined time. Therefore, when the time when the video is muted is different, for example, when the television receiver is in the hot state or the cool state. However, it is possible to prevent the short screen display from being overlooked and the long screen display from getting in the way because the display time becomes constant.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of a process of a video processor when the power is turned on.

FIG. 3 is a flowchart of processing of a microcomputer performed when power is turned on.

[Explanation of symbols]

 3 Video Processor 4 Drive Circuit 6 Counter 10 Character Generator 11 On Screen Display Ik Cathode Current

Claims (4)

[Claims] 1. A television receiver comprising at least a cathode ray tube for displaying a video signal output from a video processor, and a control circuit for performing a surface display on the cathode ray tube for a predetermined time by turning on a power source. A television receiver characterized in that the start time of the screen display is set on the basis of a control signal output when the cathode current of the cathode ray tube exceeds a certain value. 2. The television image receiving apparatus according to claim 1, wherein the control signal is formed by detecting a cathode current when a reference drive signal inserted in the vertical blanking period is output. Machine. 3. The television receiver according to claim 1, wherein the display time on the screen is set by a count value of a counter provided in the control circuit. 4. The television receiver according to claim 1, wherein the screen display start time is at least after the video mute is released.