JP2002218349A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time until a screen is displayed, when switching channels and at the same time reduce load to eyes with a display device. SOLUTION: An input means 1a inputs an mage signal. A detection means 1c detects, for example, when a reception channel is switched and reports the detection to an image signal adjustment means 1d. The image signal adjustment means 1d gradually cancels blanking from a stage, before a complete image signal has been outputted for supplying to an output means 1b. The output means 1b supplies an image signal that has been adjusted, by the image signal adjustment means 1d to a display section 1f for display.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to a display device for inputting and displaying a video signal.

[0002]

2. Description of the Related Art Conventionally, when an operation of switching a receiving channel of a television receiver is performed, blanking is applied to a video signal until a video of a new channel is displayed, and noise is generated due to an asynchronous state. And the like, so as to prevent the display of a video signal including the like on the screen.

[0003]

However, since the blanking time is relatively long, about 100 msec, there is a problem that it is not clear whether the channel switching has been performed normally. Further, as a result, there is a problem in that an extra operation is performed and a longer time may be required until a target channel is received.

After the blanking period ends,
Since a new video signal is displayed instantaneously, there is also a problem that the burden on eyes is large. The present invention has been made in view of the above points, and an object of the present invention is to provide a display device capable of shortening the time until a new image is displayed due to channel switching or the like. And

Another object of the present invention is to provide a display device capable of reducing the burden on the eyes when switching channels.

[0006]

According to the present invention, in order to solve the above problems, in a display device for inputting and displaying a video signal, an input means for inputting a video signal, and an output for outputting the video signal to a display unit Means, a detecting means for detecting that the state of the video signal output from the output means has changed, and an image output from the output means when the detecting means detects that the state of the video signal has changed. Video signal adjusting means for adjusting the amplitude of the signal to gradually increase;
A display device characterized by having:

Here, the input means inputs a video signal. The output means outputs the video signal to the display. The detecting means detects that the state of the video signal output from the output means has changed. The video signal adjusting means adjusts the amplitude of the video signal output from the output means to gradually increase when the detection means detects that the state of the video signal has changed.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a principle diagram for explaining the operation principle of the present invention. As shown in the figure, the display device 1 according to the present invention includes an input unit 1a, an output unit 1b, a detection unit 1c, a video signal adjustment unit 1d, and a display unit 1f.

Here, the input means 1a inputs a video signal. The output unit 1b outputs a video signal to the display unit 1f. The detecting means 1b detects that the state of the video signal output from the output means 1b has changed. The change in the state of the video signal is detected by monitoring either the input unit 1a or the output unit 1b.

The video signal adjusting means 1d adjusts the amplitude of the video signal output from the output means 1b so as to gradually increase when the state of the video signal is detected by the detecting means 1c. .

Next, the operation of the above principle diagram will be described. The input unit 1a receives, for example, radio waves from a satellite (not shown), selects and demodulates a signal of a desired channel, and outputs an obtained video signal.

The detecting means 1c detects, for example, that a new video signal has been output from the input means 1a or that the receiving channel has been switched when the display device 1 is powered on, and that the video signal adjusting means 1d receives the signal. Notice.

When the detecting means 1c detects that a new video signal has been supplied to the display section 1f, the video signal adjusting means 1d first executes a blanking process so as to execute a blanking process, A video signal containing noise at the time of channel switching is prevented from being directly supplied to the display unit 1f and displayed. Then, when a predetermined time has elapsed, the blanking is gradually released.

The output means 1b supplies the video signal adjusted by the video signal adjusting means 1d to the display section 1f for display. As a result, when the power is turned on,
When the channel is switched, first, the display unit 1f is in a non-display state by the blanking process, and after a predetermined time has elapsed, an image is gradually displayed on the display unit 1f. As a result, unlike the related art, a new video is not displayed instantaneously, so that the burden on the eyes can be reduced.

Further, if the blanking is canceled earlier than before, the state where the display section 1f is not displayed can be shortened. In this case, a somewhat distorted image is displayed. However, since the display is performed in a state where the luminance is low, it is considered that the image is less disturbed.

Next, an embodiment of the present invention will be described. FIG. 2 is a diagram illustrating a configuration example of the embodiment of the present invention. As shown in this figure, the display device 50 according to the present invention
Is an antenna 51, a receiving unit 52, a video signal extracting unit 53,
Video signal demodulation unit 54, tuning control unit 55, D / A (Digita
l to Analog) converter 56, blanking controller 57,
CRT (Cathode Ray Tube) 58 and remote control 5
9.

Here, the antenna 51 captures, for example, radio waves from artificial satellites and terrestrial broadcast radio waves. Receiver 5
2 selects a radio wave of a predetermined channel from the radio waves captured by the antenna 51 under the control of the tuning control unit 55, converts the radio wave into an electric signal, and supplies the electric signal to the video signal extraction unit 53.

The video signal extracting section 53 extracts a video signal from the signal supplied from the receiving section 52 (a signal in which the video signal and the audio signal and the like are superimposed) and supplies the video signal to the video signal demodulating section 54.

The video signal demodulation unit 54 includes a video signal extraction unit 5
3 is demodulated to generate R, G, B signals and supplied to the blanking control unit 57. The tuning control unit 55 receives the infrared signal transmitted from the remote control 59, notifies the receiving unit 52 to select the channel specified by the viewer, and sets the vertical synchronization supplied from the video signal demodulation unit 54. The D / A converter 56 is instructed to start the blanking process with reference to the signal.

The D / A converter 56 controls the transistor 57c in accordance with an instruction from the tuning controller 55 to blank the video signal. The blanking control unit 57
It is configured by a resistor 57a and transistors 57b and 57c, and performs a blanking process on the video signal supplied from the video signal demodulation unit 54 under the control of the D / A conversion unit 56. Although only the configuration for the signal B is shown in this figure, there is actually a blanking control unit for each of the signals R and G.

The CRT 58 displays and outputs the video signal subjected to the blanking process by the blanking control section 57. The remote controller 59 transmits an infrared signal according to the operation of the viewer to the tuning control unit 55.

Next, the operation of the above embodiment will be described. As shown in FIG. 3A, the A channel (c
h) is being received, and it is assumed that an operation of switching to the B channel by the remote controller 59 is performed at time t1. Then, the tuning control unit 55 receives the infrared signal transmitted from the remote controller 59, recognizes that the switching to the B channel has been requested, and instructs the D / A conversion unit 56 to start blanking. The designated data "0" is output.

As a result, the output of the D / A converter 56 is at the ground level, so that the emitter-collector of the transistor 57c is short-circuited. By the way, the transistor 57b and the transistor 57c form an AND circuit, and when one of the inputs becomes "0", the output becomes "0" as a whole (see FIG. 3D). The output of the unit 57 becomes "0", and as a result, the CRT
Reference numeral 58 indicates a blank (blank) state.

When the CRT 58 enters the non-display state, the tuning control unit 55 requests the receiving unit 52 to switch to the B channel. Receiving section 52 receives the request from tuning control section 55 and executes processing for switching the receiving channel to B channel. That is, after performing the process of switching the receiving frequency to the natural frequency of the B channel, the receiving unit 52 sets the built-in AFT (AutoFrequency Tuning) to a wide range (Wide Range) (see FIG. 3B). , The reception frequency is adjusted in units of 2 MHz. When the AFT scans in a wide range, since the deviation from the natural frequency is large, the video signal is in a disordered state. “0” is continuously output, and the blanking state is continued as shown in FIG.

At time t2, when the scanning in the wide range is completed, the receiving section 52 changes the AFT to the narrow range (see FIG. 3B), and starts fine adjustment of the receiving frequency in units of 200 KHz.

When the receiving unit 52 starts scanning in the narrow range, the tuning control unit 55 changes the value of the data output to the D / A conversion unit 56 as shown in FIG.
It is increased stepwise in synchronization with the vertical pulse signal shown in FIG.

FIG. 4 shows a vertical pulse signal and a D / A converter 5.
6, a blank (BLK) signal and D /
FIG. 7 is a diagram illustrating timing of data supplied to an A conversion unit. As shown in (C) of this figure, the tuning control unit 55
Is D / A in synchronization with the vertical pulse signal shown in FIG.
The D / A control data is supplied to the converter 56. Since the D / A control data gradually increases, the output of the D / A converter 56 increases in synchronization with the vertical pulse signal.

When the output of the D / A converter 56 increases, the base voltage of the transistor 57c increases accordingly,
The current flowing between the emitter and the collector gradually decreases, and the transistor 57c is gradually turned off. As described above, since the transistor 57b and the transistor 57c form an AND circuit, when the transistor 57c is gradually turned off, the output of the transistor 57b gradually increases, and the level of the video signal supplied to the CRT 58 is increased. Gradually increases. Then, the image of the B channel is gradually displayed on the CRT 58.

At this time, since the output of the D / A converter 56 increases in synchronization with the vertical synchronization pulse, the state of the transistor 57c is constant during one frame scanning. Therefore, during one frame period, the level of the video signal supplied to the CRT 58 is constant, so that it is possible to prevent the luminance from being different depending on the frame part.

At the time t3, when the scanning in the narrow range is completed, the output from the D / A converter 56 becomes maximum, and the transistor 57c is completely shut off, so that the blanking state is released. The image of channel B is displayed in a perfect state.

The same processing as described above is performed when the reception channel is switched from channel B to another channel. As described above, according to the present embodiment, when the operation of switching the channel is performed, and when the AFT scans in the wide range, the image is in a disordered state, so that the blanking state is set. , When the AFT is changed to the narrow range, the blanking is gradually released, so that the video is displayed in a shorter time than the conventional blanking processing shown in FIG.
It can be displayed on the RT 58.

When the blanking is canceled, the level of the video signal is gradually increased, so that a switching operation that is easy on the eyes can be realized. Further, when canceling the blanking, the D / A is synchronized with the vertical pulse signal.
Since the output of the conversion unit 56 is changed, it is possible to prevent the brightness of the screen from being partially different by changing the brightness of the video in frame units.

In the above embodiment, the blanking is canceled after the AFT is changed to the narrow range. However, the present invention is not limited to such a case. For example, it is possible to display an image even before the narrow range is set. In this case, although the possibility that a disturbed image is displayed cannot be denied, the display of the image can be started earlier than in the above-described case.

Further, in the above embodiment, the blanking is gradually released when the AFT is changed to the narrow range. However, for example, the amplitude of the video signal may be directly controlled. FIG. 5 is a timing chart showing the operation of the embodiment when the video signal is directly controlled.

In the example shown in FIG. 5, at time t1, FIG.
When the channel switching is executed as shown in FIG. 5A and the AFT is set to the wide range as shown in FIG. 5B, the video signal is narrowed down as shown in FIG. 5C. State.

When the AFT is changed to the narrow range at time t2, the amplitude of the video signal is gradually increased as shown in FIG. 5C, and reaches the maximum amplitude (normal amplitude) at time t3. Is controlled so that

According to the above-described embodiment, as in the case of the embodiment shown in FIG. 1, it is possible to perform channel switching so as not to burden the eyes. In addition,
In the present embodiment, the description has been given by taking the case of switching the channel as an example. However, for example, the same processing is performed when the power is turned on or when the input signal is switched (for example, when switching to the video signal input). Accordingly, it is possible to display an image in a shorter time as compared with the related art, and to perform a display that is easy on the eyes.

In the present embodiment, blanking is canceled linearly as shown in FIG. 3 (D). However, the blanking is canceled exponentially in accordance with the sensitivity of human sense organs. Is also possible. According to such a method, it is possible to give an impression that the luminance of the screen changes linearly.

In the above embodiment, the television receiver has been described as an example. However, for example, a CRT monitor of a computer or an LCD (Liquid Crystal Displ.
The present invention can also be applied to ay) and the like.

Further, in the above embodiment, the D / A converter 56, the transistors 57b and 57c, and the resistor 57a
Is used to perform blanking, but such a circuit is merely an example, and it goes without saying that the present invention is not limited only to such a case. In short, CRT
For example, the brightness of the video signal supplied to the display unit may be gradually changed by some means.

[0041]

As described above, according to the present invention, in a display device for inputting and displaying a video signal, input means for inputting a video signal, output means for outputting a video signal to a display unit, and output means Detecting means for detecting that the state of the output video signal has changed; and when the detecting means detects that the state of the video signal has changed, the amplitude of the video signal output from the output means gradually increases. Video signal adjusting means for adjusting the image signal to increase so that it is possible to start displaying the image at a timing earlier than before, for example, at the time of channel switching, and to provide a display that is easy on the eyes. become.

[Brief description of the drawings]

FIG. 1 is a principle diagram for explaining the operation principle of the present invention.

FIG. 2 is a diagram illustrating a configuration example of an embodiment of the present invention.

FIG. 3 is a timing chart for explaining the operation of the embodiment shown in FIG. 2;

FIG. 4 shows a vertical pulse signal, a BLK signal, and D / A
6 is a timing chart for explaining a relationship between control data.

FIG. 5 is a timing chart for explaining the operation of another embodiment of the present invention.

[Explanation of symbols]

1 display device, 1a input means, 1b output means, 1c detection means, 1d video signal adjustment means, 1
f: display unit, 50: display device, 51: antenna,
52 receiving section, 53 video signal extracting section, 54 video signal demodulating section, 55 channel selection control section, 56 D / A conversion section, 57 blanking control section, 57a resistance,
57b, 57c: Transistor, 58: CRT

Claims (8)

[Claims] 1. A display device for inputting and displaying a video signal, comprising: input means for inputting a video signal; output means for outputting a video signal to a display unit; and a state of the video signal output from the output means. Detecting means for detecting the change; and when the detecting means detects that the state of the video signal has changed, adjusting the amplitude of the video signal output from the output means so as to gradually increase. A display device, comprising: video signal adjusting means. 2. The display device according to claim 1, wherein said video signal adjusting means adjusts the video signal stepwise in synchronization with a vertical synchronization signal. 3. The apparatus according to claim 1, wherein said detecting means detects that a new video signal has been input, and said video signal adjusting means gradually releases blanking for the new video signal. The display device according to the above. 4. The apparatus according to claim 1, wherein said detection means detects that the input of the video signal has been switched.
The display device according to the above. 5. The display device according to claim 1, wherein the detection means detects that the device is turned on and a new video signal is supplied. 6. The display device according to claim 1, wherein said detection means detects that a reception channel has been switched. 7. The video signal adjusting means performs blanking on the video signal when the AFT is scanning in a wide range at the time of switching the receiving channel, and performs scanning in the narrow range with the AFT. 7. The display device according to claim 6, wherein when started, blanking applied to the video signal is gradually released. 8. The display device according to claim 1, wherein the video signal adjusting means gradually reduces the amplitude of the video signal and then gradually increases the amplitude.