JP3104753B2 - Display device burn-in prevention method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing burn-in of a display device used for, for example, a VTR.

[0002]

2. Description of the Related Art For example, in a VTR for a broadcasting station, a plurality of status display images such as a tape running state, a VTR mode state, a time code, a remaining tape time, an operation switch input state, and an audio signal level are displayed. , Are simultaneously displayed on one screen of a display as a man-machine interface between the VTR and the user. For this reason, as a display device used for this type of VTR, for example, a large-capacity display device made of EL is used.

[0003] By the way, this type of VTR for a broadcasting station is often used all day long. Therefore, the above-described large-capacity display device displays a state display image having the same contents at the same position on the screen for a long time. If the display is continued, burn-in may occur. And when this burn-in occurs,
The uniformity of the brightness of the display image deteriorates, and the contents of the display image become difficult for the operator to see.

Therefore, in order to prevent or alleviate the burn-in, conventionally, when the continuous display time of the same content continues for a predetermined time or more, the display image is erased or only the display which does not cause the burn-in is performed. There are known technologies.

[0005] As described in, for example, Japanese Patent Application Laid-Open No. 1-241596, a "recording apparatus that switches and displays a plurality of screens using a display on a user interface and inputs and sets function selection and execution conditions. Switching to a screen in which the display position moves at predetermined time intervals on the condition that the same screen is displayed without any change in display content continuously for a predetermined time or more "is also performed.

[0006]

However, if the display screen is turned off or only a small amount of display is performed in order to prevent burn-in as in the former case, information for managing the state of the VTR is not sufficient. Not enough.

In the case of the latter system,
When the display image contents of the plurality of screens to be switched and displayed are images that use the entire display screen range, there is no space for moving the image, and the display image is substantially moved. And the effect of preventing image sticking cannot be exhibited. That is, it is necessary to previously secure a moving space for preventing image sticking. Therefore, it is necessary to use only a part of the display space as the image content displayed as one screen. Therefore, the amount of information displayed not only at the time of preventing burn-in but also at the normal time as one screen is reduced. As in the case of the above-described VTR, the entire display screen space is effectively used, and the abundance of the aforementioned It is unsuitable when information must be displayed.

In view of the above, the present invention can display a wealth of information on a normal display screen, and can also display the necessary information on a screen for preventing or reducing burn-in, and at the same time, has an effect of preventing burn-in. It is an object of the present invention to provide a method for preventing burn-in of a display device, which can effectively obtain the image quality.

[0009]

According to the present invention, there is provided a method for preventing burn-in, when a display image having the same content is continuously displayed at the same position on a display screen, when the continuous display time exceeds a predetermined time. Erasing part of the displayed image,
Utilizing the resulting vacant space on the display screen, the display position of the remaining portion of the display image is moved within the display screen to prevent or reduce burn-in of the display device.

When the continuous display time is equal to or longer than a predetermined time, the display image is reduced, and the display position of the display image is displayed using the resulting empty space on the display screen. You may make it move within a screen.

[0011]

According to the above arrangement, display images having the same contents are continuously displayed at the same position on the display screen, and when the continuous display time exceeds a predetermined time, unnecessary display image portions are deleted. Alternatively, the display image is reduced to form an empty space in the screen. Then, the display image is moved using the empty space, and burn-in is prevented.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for preventing image sticking of a display device according to the present invention will be described below with reference to the drawings, taking an example in which the present invention is applied to a display device of a VTR for a broadcasting station.

FIG. 2 shows an example of hardware of a display microcomputer which mainly performs display control of the VTR of this embodiment. In the figure, 1 is a CPU, 2 is a ROM in which a program to be described later is written, 3 is a RAM for a work area, 4 is a display controller, 5 is a display made of, for example, EL, 6 to 8 are interface circuits, and 9 is data It is a bus.

Reference numeral 12 denotes a key input operation unit of the VTR, which inputs signals corresponding to key input operations of various keys to the data bus 9 via the interface circuit 7.

Reference numeral 11 denotes a timer for measuring the time during which display images of the same content are continuously displayed at the same position on the screen as will be described later. The display time information is input, and a timer reset signal is supplied to the timer 11. Generally, when a key input is performed on the key input operation unit, the content of the displayed image is changed accordingly. Therefore, the timer 11 is reset every time a key operation is performed on the key input operation unit 12. Therefore, the timer 11 functions as a key monitoring timer that counts a time interval at which a key operation is performed on the input operation unit 12.

Reference numeral 13 denotes a VTR system controller.
A command signal corresponding to a key input operation is supplied to the system controller 13 via the interface circuit 8, and the VT
A status signal indicating the state of R is input to data bus 9.

FIG. 1 is a block diagram showing functions for controlling image display in the apparatus shown in FIG.

When a key input operation is performed on the key input operation section 12, a command signal corresponding to the key input operation is transmitted to the command generation means 21 of the display microcomputer 20.
Generated in And the command signal is VT
R is supplied to the system controller 13 of R.
The mode is set according to the command signal. Then, a status signal indicating the state of the VTR is obtained from the system controller 13 and supplied to the display image generating means 22 of the display microcomputer 20.

The display image generating means 22 includes a plurality of types of status display images required for the user to recognize the status of the VTR at that time from the status signal, for example, the running status of the tape, the VTR mode, and the time code. , The remaining time of the tape, the input state of the operation switch, the level of the audio signal, and the like, and the data of the state display image. The display image data is supplied to the display control means 23, and a plurality of state display images are displayed on the display 5 under the control of the display control means 23.

The operation of the display control means 23 depends on the timer time from the timer 11. As described above, the timer 11 is reset every time a key input operation is performed on the key input operation unit 12, and measures the time interval of the key input operation on the key input operation unit 12. Since the display corresponding to the VTR mode state corresponding to the key input is performed on the display 5, the continuation time during which the same image is continuously displayed at the same position is determined by the timer 1.
1 will be measured.

As will be described later, when the same image continuation display time on the timer 11 is equal to or shorter than a predetermined time Ts at which no burn-in occurs, a normal screen as described later is displayed on the display 5. You. At this time, the display control unit 23 refers to the display position table 24 to display all of the plurality of types of state display images generated from the display image generation unit 22 to represent the state of the VTR at that time, with reference to the display position table 24. A display control operation is performed so as to fixedly display at a predetermined display position on the screen of No. 5.

FIG. 3 is a diagram showing an example of a plurality of types of status display images displayed on the display 5 as a normal screen. In this example, the normal screen includes seven types of status display partial images 51 to 57.
Are displayed in one screen. FIG. 3A shows each of the partial images 51 to 57 only by a rectangular outline thereof, and FIG. 3B shows a specific display image example of each of the partial images 51 to 57.

A partial image 51 is an image showing a tape running state, a partial image 52 is an image showing a time display by a time code, a partial image 53 is an image showing a cue time display, and a partial image 54 is a tape remaining time. The image shown, the partial image 55 is an image for showing the input / output state of the VTR and the use situation, the partial image 56 is a display image showing the level of the audio signal of each channel, and the partial image 57 is an image showing the tape state by a bar display. It is.

The key input operation is performed for the predetermined time Ts.
The above-mentioned seven types of partial images 51 to 57
Is displayed at the fixed display position of the display 5 continuously over the time Ts or more, the display control means 23 changes the display screen of the display 5 as shown in FIG. The normal operation screen is changed to a protection operation screen for preventing burn-in as shown in FIG. 4B.

In this case, in this protection operation screen, FIG.
Among the seven types of partial images 51 to 57 of the normal screen, relatively insignificant partial images 53, 55 and 57 are deleted,
An empty space is formed in the screen of the display 5.
In addition, in the protection operation screen of FIG. 4B immediately after the change from the normal screen, as is clear from the figure, the display positions of the displayed partial images 51, 52, 54, and 56 on the display 5 are the same as those of the normal screen. It has been different from time.

When the state of the protection operation screen continues for a predetermined time tm or longer, the displayed partial images are used every time the predetermined time tm elapses by using the empty space portion, as shown in FIGS. As shown in FIG. 4D, the display position is changed, and burn-in is prevented. At this time, FIG.
As shown in C and D, some partial images In this example, the audio level display partial image 56 is reduced so that an empty space is further formed on the display 5 and the partial image 5
The display position of the 6 reduced image 56 ^* is changed using this empty space. In this example, the partial image 56
Indicates that the horizontal direction is reduced, and the partial image 5 on the normal screen is displayed.
6 has a horizontal length a, and a reduced partial image 5 of the protection operation screen.
The horizontal length of 6 ^* is b (b <a).

In this case, for the protection operation screen display, the display position table 24 stores the display position for each lapse of time tm, and the display control means 23 displays the display table 24 during the protection operation. By referring to the partial images 51, 52, 54, 56, and 56 for each lapse of time tm,
The display position of * on the display 5 is determined. Further, as described later, the partial image 5
6, the data of the reduction ratio is also stored, and the display control means 23 controls the reduction of the partial image 56 with reference to the data.

In this example, as shown in FIG. 4A, the display 5 is made up of an EL of 200 dots vertically and 640 dots horizontally. 51 to 57 are displayed at predetermined rectangular dot range positions.

In the display position table 24, for example, assuming that the lower left corner of the screen of the display 5 is the coordinate origin, the Y coordinate is taken in the vertical direction and the X coordinate is taken in the horizontal direction. Of each partial image 5 for each time tm
1,52,54,56 display position information (including a reduced image 56 ^*) is the lower left corner of the dot position of the rectangular display area of each partial image 51,52,54,56 (or reduced image 56 ^*) It is written as an X coordinate and a Y coordinate.

FIG. 5 shows an example of the contents stored in the display position table 24. The count value of the display position counter is:
As will be described later, it is increased every time the time tm elapses. That is, the count value = “1” is the protection operation screen immediately after the normal screen, and thereafter, the count value changes to “2”, “3”... Every time tm elapses. Although not shown in FIG. 5, the count value of the display counter = "0"
Is the time when the normal screen is displayed.
The display position information for all of the partial images 51 to 57 is stored in the display position table 24, and the display control means 23 displays a normal screen on the display 5 based on the coordinate position information. is there.

In the display position table 24, the horizontal length of the image 56 of the audio meter section is stored as the number of dots w. The number of dots w is w = a = 100 on a normal screen, and w = b = 60 when the count value of the display position counter is “2” or more.
It has been. When w = b = 60, the image becomes w = b = 60.
When a = 100, display is performed by thinning out dots that are pixels in the horizontal direction of the image.

Next, the display control operation of the display control means 23 will be described with reference to the flowcharts of FIGS.

In this example, the display control operation on the display 5 is performed by executing the interrupt processing routine 100 every 1/60 second (one frame cycle). That is, when an interrupt occurs (step 10
1) It is determined whether or not a key input operation has been performed on the key input operation unit 12 (step 102).

If it is determined in step 102 that the key has been pressed, the flow advances to step 201, where the key monitoring timer 1
Reset 1 Then, it is determined whether or not the protection operation is being performed at that time (step 202). If the protection operation is being performed, the process proceeds to step 203 to reset the display position counter, and then proceeds to step 113 (FIG. 7) and thereafter. If the protection operation is not being performed, the process immediately proceeds from step 202 to step 113. The display position counter can be realized by software, for example.

In step 113, it is determined whether or not the contents of the previous display position memory equal to the contents of the display position counter before the interruption are equal to the count value of the display position counter.

When it is determined that the key input operation has been performed, if the state before the interruption is the protection operation, the protection operation screen is being displayed on the display 5. Then, since the display position counter is reset in step 203, the contents stored in the previous display position memory are different from the count value of the display position counter. In this case, the process proceeds from step 113 to step 114 to rewrite the contents of the previous display position memory with the count value of the display position counter at that time. Then, the process proceeds to step 115, where the display position coordinates of each partial image are read from the display position table 24 based on the count value of the display position counter at that time, and the necessary partial image is displayed on the display 5.
At this time, since the count value of the display position counter is "0", a normal screen is displayed on the display 5, and the display images 53, 55, and 5 that have been erased in the protection operation screen are displayed.
7 returns to the screen of the display 5. Thereafter, the process proceeds to step 116 to exit the routine 100 and return to the main routine.

When the key input operation is performed, if the state before the interruption is not the protection operation, the display 5 is displaying the normal screen and the content of the previous display position memory is "0". Since the count value of the display position counter is also "0", the content of the previous display position memory is equal to the count value of the display position counter.
And returns to the main routine. At this time, the display screen on the display 54 continues the normal screen.

On the other hand, if it is determined in step 102 that the key has not been pressed, the flow advances to step 103 to advance the key monitoring timer 11. Then, the process proceeds to a step 104, wherein it is determined whether or not the timer 11 has reached the protection operation start value = Ts.

If the result of the determination in step 104 is that the monitoring timer 11 has reached the protection operation start value = Ts, the routine proceeds to step 105, where it is determined whether or not the protection operation is being performed. If the protection operation is not being performed, that is, if the display is in the normal screen display state, the process proceeds to step 106, where the display position counter is incremented by one, and the count value of the display position counter before the count-up is stored in the previous display position memory. Write. Further, the movement timer for managing the movement of the image at every time tm during the protection operation is reset. This movement timer may be externally attached like the timer 11, but may be a software timer. After step 106, the process proceeds to step 107, where the display images 53, 55, and 57 selected from the normal screen as unimportant are deleted, as described above. Thereafter, the process proceeds to step 109. If it is determined in step 105 that the protection operation is being performed, steps 106 and 107 are skipped, and the process immediately proceeds to step 109.

If the result of the determination in step 104 shows that the key monitoring timer 11 has not yet reached the protection operation start value = Ts, the flow advances to step 108 to determine whether or not the protection operation is being performed. If it is determined in step 108 that the protection operation is not being performed, that is, if the normal screen is being displayed, the process proceeds to step 113, and the routine 100 is exited via step 116 in the same manner as described above. On 5, the normal screen is continued. If it is determined in step 108 that the protection operation is being performed, the process proceeds to step 109.

In step 109, it is determined whether or not the value of the movement timer has reached a predetermined time tm. When the movement timer has reached the predetermined time tm, the process proceeds from step 109 to step 110. After resetting the movement timer, the process proceeds to step 111, where the display position counter is counted up by one. Thereafter, the process proceeds to step 113. And
If the movement timer has not reached the predetermined time tm,
The process proceeds from step 109 to step 112, in which the movement timer is advanced, and then proceeds to step 113.

In this flowchart, step 1
The operation in the state where no key is pressed in 02 will be described below by state.

That is, when it is determined in step 102 that the key has not been pressed, it is determined in step 104 that the key monitoring timer 11 has not reached Ts, and in step 108 it is determined that the protection operation is not being performed. At the time, as described above, the normal screen is being displayed,
In step 113, it is determined that the content of the previous display position memory is equal to the count value of the display position counter. Therefore, the process proceeds from step 113 to step 116 to exit this interrupt routine 100, and the display 5 continues to display the normal screen.

If it is determined in step 104 that the key monitoring timer 11 has not reached Ts, and if it is determined in step 108 that the protection operation is being performed, the display 5 is displaying the protection operation screen. At this time, if the value of the movement timer is not equal to tm in step 109, step 111 is not passed, and the count value of the display position counter does not change. Therefore, in step 113, it is determined that the contents of the previous display position memory and the count value of the display position counter are equal, and the process proceeds from step 113 to step 116 to exit this interrupt routine 100. At this time, the display of the previous protection operation screen is continued on the display 5.

Further, in this case, if it is determined in step 109 that the value of the movement timer has become equal to tm, the display position counter is incremented by one. When it is determined that the count value of the position counter is not equal, the process proceeds to steps 114 and 115, and after the content of the previous display position memory is rewritten to the count value of the new display position counter, the count value of the new display position counter is changed. The coordinate values on the display position table 24 indicated by are read out, and the display position of each image on the protection operation screen is changed.

At this time, as shown in FIG. 5, in the display position table 24, if the count value of the display position counter is "2", the number x of dots in the horizontal direction of the image 56 of the audio meter section is x. = B = 60, the number of dots x = a = 100 when the normal screen and the count value of the display position counter are “1”, so that the horizontal dots are thinned out and displayed on the display 5. Is displayed as a reduced image 56 ^* as shown in FIG. 4C.

Thereafter, the routine proceeds to step 116, where the interruption routine 100 is exited. Thus,
During the continuation of the protection operation screen, as shown in FIGS. 4B to 4D, each partial image is moved to the coordinate position registered in the display position table 24 every time tm.

On the other hand, at step 104, the key monitoring timer 1
When the value of 1 has reached Ts, that is, when the time during which no key operation has been performed continuously for Ts or more has reached Ts, unless the protection operation is being performed in step 105, the normal screen is displayed on the display 5 until then. It is the state that was displayed. In this case, the unimportant images are deleted in step 107. Then, since the movement timer is reset in step 106, step 111 is not passed. However, in step 106, the count value of the display position counter is incremented by one. Are not equal to each other. For this reason, the process proceeds from step 113 to step 114 and step 115, in which the content of the previous display position memory is rewritten to the count value of the new display position counter, and then the display position table indicated by the count value of the new display position counter is written. The coordinates on 24 are read out and displayed on the display 5. As a result, the display screen of the display 5 changes from the normal screen as shown in FIG. 4A to the protection operation screen as shown in FIG. 4B. afterwards,
Proceeding to step 116, the interrupt routine 100
Escape.

When the value of the key monitoring timer reaches Ts in step 104 and the protection operation is being performed in step 105, the protection operation screen is being displayed on the display 5. In this case, if the value of the movement timer is not equal to tm in step 109, step 11
Since 1 does not pass, the count value of the display position counter does not change. Therefore, in step 113, it is determined that the content of the previous display position memory is equal to the count value of the display position counter.
In step 6, the CPU exits the interrupt routine 100 and continues displaying the previous protection operation screen on the display 5.

Further, when the value of the key monitoring timer reaches Ts, the value of the movement timer is set to tm in step 109.
When the display position counter is determined to have become equal to 1, the display position counter counts up by one. Therefore, in step 113, it is determined that the contents of the previous display position memory and the count value of the display position counter are not equal, and steps 114 and 115 are performed. After rewriting the contents of the previous display position memory with the count value of the new display position counter, the coordinate values on the display position table 24 indicated by the count value of the new display position counter are read out, and Similarly, the display position of each image on the protection operation screen is changed. Then, the process proceeds to step 116 to exit this interrupt routine 100.

The display position counter is configured to return to the count value "1" when the count value reaches a constant value, and each image in the protection operation screen has moved to the full empty space. Thereafter, the display returns to the position of the count value "1" of the display position counter, and this is repeated.

As shown in steps 301 to 303 of the initialization flowchart of FIG. 8, when the power is turned on, the key monitoring timer 11, the movement timer, and the display position counter are all reset. I have.

Although the above description has been given of the case where the present invention is applied to a display device of a VTR, it is needless to say that the present invention can be applied to all display devices which may cause burn-in.

[0054]

As described above, according to the present invention, in a display device in which a display image having the same content is continuously displayed at the same position on a display screen, the continuous display time is longer than a predetermined time. When it becomes unnecessary, for example, some unimportant display images were deleted, or the display image was reduced to form an empty space, and the image was moved and displayed using this empty space, so it was used as a normal screen Can display a wealth of information using the entire screen and can always display the required display image even on a protection screen for preventing burn-in.

Therefore, when the display screen is used as a man-machine interface, the effect of preventing burn-in can be obtained while necessary information is always secured.
The practical effect is remarkable.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of a display control device of a VTR to which a method for preventing burn-in of a display device according to the present invention is applied.

FIG. 2 is a diagram showing an example of hardware of a display control device of a VTR to which the method for preventing burn-in of a display device according to the present invention is applied.

FIG. 3 is a diagram showing an example of a display screen in a normal state in the examples of FIGS. 1 and 2;

FIG. 4 is a diagram for explaining an example of a display screen at the time of a burn-in protection operation in the examples of FIGS. 1 and 2;

FIG. 5 is a diagram showing an example of a table used for explaining the examples of FIGS. 1 and 2;

FIG. 6 is a part of a flowchart for explaining the example of FIGS. 1 and 2;

FIG. 7 is a part of a flowchart for explaining the example of FIGS. 1 and 2;

FIG. 8 is a flowchart of initialization at power-on.

[Explanation of symbols]

5 Display 11 Timer 12 Key Input Operation Unit 21 Command Generation Unit 22 Display Image Generation Unit 23 Display Control Means 24 Display Position Table 51 Partial Image 52 Partial Image 53 Partial Image 54 Partial Image 55 Partial Image 56 Partial Image 56 ^* Reduced Image

Claims (2)

(57) [Claims] When a display image having the same content is continuously displayed at the same position on a display screen, a part of the display image is deleted when the continuous display time exceeds a predetermined time. A burn-in prevention method for a display device, wherein a display position of a remaining portion of the display image is changed in the display screen by using a resulting vacant space of the display screen. 2. In a case where display images having the same content are continuously displayed at the same position on a display screen, when the continuous display time exceeds a predetermined time, the display image is reduced, and the resulting display image is reduced. Use the empty space on the display screen,
A burn-in prevention method for a display device, wherein a display position of the display image is changed in the display screen.