JP2004064364A - Cathode ray tube display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify the configuration of a cathode ray tube display for preventing spot remainder. <P>SOLUTION: The cathode ray tube display comprises a cathode ray tube 7 for performing operation for displaying an image: a microcomputer 1 for controlling the start and stop of the operation of the cathode ray tube 7 according to operation for turning on and off a power supply by a power key 11; and a white background display circuit 2 for allowing the cathode ray tube 7 to display a white background image. The white background display circuit 2 is connected to the microcomputer 1 for control by a data communication bus 10, and allows the cathode ray tube 7 to display the white background image when action indication data having content of white display are inputted from the microcomputer 1 for control. Then, by the operation for turning off the power supply, the operation of the cathode ray tube 7 is stopped after the microcomputer 1 for control outputs the action indication data to the white background display circuit 2 for allowing the cathode ray tube 7 to display the white background image. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cathode ray tube display device such as a television receiver having a cathode ray tube.
[0002]
[Prior art]
A cathode ray tube display device including a cathode ray tube operates to display an image on a screen of the cathode ray tube. In displaying an image on the cathode ray tube, a high voltage is applied to the cathode ray tube to accelerate an electron beam, and the electron beam collides with a screen of the cathode ray tube to emit light, thereby forming an image.
[0003]
By the way, when the power of the cathode ray tube display device is turned off to stop the operation, a lightning-like light emission called a so-called spot residue may appear on the screen. That is, since a high voltage for accelerating the electron beam was applied to the cathode ray tube, the electron beam was not turned off even after the power was turned off due to the influence of the charge remaining on the capacitor formed on the inner and outer conductive films of the cathode ray tube. The screen may emit light due to acceleration of the image.
[0004]
Such light emission of the screen that occurs after the power is turned off is unsightly and gives an unpleasant impression to the viewer. Therefore, various measures are taken to prevent the screen from emitting light after the power is turned off.
[0005]
[Problems to be solved by the invention]
Here, as a television receiver configured to prevent the above-mentioned spot remaining, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. 4-2169. However, the television receiver disclosed in the above publication has a complicated configuration in which a circuit for preventing spot remaining is composed of many circuit elements.
[0006]
Therefore, an object of the present invention is to provide a cathode ray tube display device which can prevent spot remaining and which is simply configured.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a cathode ray tube that performs an operation of displaying an image, a control microcomputer that controls start and stop of the operation of the cathode ray tube according to an operation of turning on and off a power supply, A white background display circuit for displaying a white background image on the cathode ray tube,
The white background display circuit is connected to the control microcomputer by a digital data transmission line, and when operation instruction data indicating that the display is to be white is input from the control microcomputer, a white background image is displayed on the cathode ray tube. Is configured to be displayed,
When the power-off operation is performed, the control microcomputer outputs the operation instruction data to the white background display circuit and causes the cathode ray tube to display a white background image, and then stops the operation of the cathode ray tube. By
A cathode ray tube display device configured to prevent spots from remaining on the cathode ray tube (claim 1).
[0008]
According to the cathode ray tube display device of the present invention, the control microcomputer outputs the operation instruction data to the white background display circuit via the digital data transmission path to display the white background image on the cathode ray tube, and then turns off the power. This can prevent spots from remaining.
[0009]
As a result, according to the cathode ray tube display of the present invention, the configuration of the circuit can be simplified in preventing the occurrence of the remaining spot. Further, the control microcomputer outputs the operation instruction data to the white background display circuit to display a white background image, thereby preventing the occurrence of a spot remaining. This makes it possible to prevent spots from remaining by a simple control procedure.
[0010]
Further, the digital data transmission path is an I2C communication bus having a data transmission path and a clock transmission path,
The control microcomputer may be configured to be able to detect that the white background display circuit has received the operation instruction data (claim 2).
[0011]
According to the present invention, the control microcomputer can detect whether or not the white background display circuit has received the operation instruction data, so that the white background image can be reliably displayed on the white background display circuit, and the occurrence of the remaining spot can be reliably determined. Can be prevented.
[0012]
The white background display circuit further includes a luminance suppressing unit that suppresses luminance of the cathode ray tube displaying an image,
In displaying a white background image on the cathode ray tube by the white background display circuit, an operation of suppressing the luminance by the luminance suppressing means may be configured to be relaxed (claim 3).
[0013]
Accordingly, when displaying the white background image on the white background display circuit, the suppression of the luminance by the luminance suppressing means can be relaxed, and a brighter white background image can be displayed. This makes it possible to more reliably prevent spots from remaining.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram schematically showing a configuration of an embodiment of the present invention, and is a block diagram showing a configuration for implementing a cathode ray tube display device according to the present invention.
[0015]
The cathode ray tube display device shown in FIG. 1 includes an operation key 11, an operation determination unit 12, a control microcomputer (hereinafter, referred to as a "control microcomputer") 1, a white background display circuit 2, and an ACL (automatic display). It includes a contrast / limiter (mitigation) circuit 15, a color signal amplifying circuit 3, a high-voltage generating circuit 5, a cathode ray tube (CRT) 7, and a power supply circuit 8.
[0016]
The operation key 11 is provided with a power key 11a for turning on (ON) and off (OFF) the power for operating the cathode ray tube display. When a user who watches a television program with this cathode ray tube display device operates the operation keys 11, the operation contents are determined by the operation determining means 12. When an operation of turning on or off the power is performed by the power key 11a, the operation determining unit 12 determines whether the power is on or off.
[0017]
When the operation determining unit 12 determines the content of the operation performed on the operation unit 11, an operation signal representing the content of the operation is input from the operation determining unit 12 to the control microcomputer 1. This allows the control microcomputer 1 to determine the content of the operation on the operation unit 11. Then, when the power key 11a is operated, the control microcomputer 1 can detect that the power-on operation or the power-off operation has been performed.
[0018]
The operation key 11 may be either an operation key provided on a main body of the cathode ray tube display device or an operation key provided on a remote controller outside the main body. When the operation keys 11 are provided on a remote controller, the operation determining means 12 can receive the transmission wave transmitted from the remote controller and determine the content of the operation.
[0019]
The control microcomputer 1 performs various controls for operating the cathode ray tube display device as a television receiver. The control microcomputer 1 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) and a RAM (Read / Write Memory), not shown. The ROM stores a power stop routine for controlling the operation of turning off the power of the cathode ray tube display.
[0020]
The control microcomputer 1 includes an I2C interface (not shown), and transmits operation instruction data to the white background display circuit 2 via a data communication bus 10 described later.
[0021]
Further, an external memory such as an E2PROM (not shown) is connected to the control microcomputer 1. The control microcomputer 1 is connected to a white background display circuit 2 described later via a data communication bus 10.
[0022]
The data communication bus 10 is used for transmitting and receiving digital data, and corresponds to a digital data transmission path. The control microcomputer 1 transmits operation instruction data as digital data to the white background display circuit 2 via the data communication bus 10.
[0023]
In the example shown in FIG. 1, the data communication bus 10 is adapted to be compatible with data communication based on I2C (INTER-INTEGRATED CIRCUIT) bus communication. The data communication bus 10 includes a data transmission line 10a for transmitting serial data and a clock transmission line 10b for transmitting clock pulses.
[0024]
The white background display circuit 2 generates color signals (R, G, B) for displaying a white background image on the cathode ray tube 7. The white background image is an image in which the entire screen of the cathode ray tube 7 is displayed in a single white color.
[0025]
The white background display circuit 2 has a data input terminal 2a and a clock input terminal 2b. The data input terminal 2a receives operation instruction data for giving the details of the operation of the white background display circuit 2. The data input terminal 2a is connected to the data transmission line 10a of the data communication bus 10.
[0026]
A clock pulse is input to the clock input terminal 2b. Then, the control microcomputer 1 can detect whether the white background display circuit 2 has received the operation instruction data in response to the reception of the clock pulse input to the clock input terminal 2b. The clock input terminal 2b is connected to the clock transmission line 10b of the data communication bus 10.
[0027]
The white background display circuit 2 can be configured by a circuit including a specific video chroma IC. When the white background display circuit 2 is configured by a specific video chroma IC, its data input terminal is connected to the data transmission line 10a, and its clock input terminal is connected to the clock transmission line 10b.
[0028]
Video chroma ICs are generally integrated circuits that process video and chroma signals. The specific video chroma IC used in the white background display circuit 2 is one that causes the cathode ray tube 7 to display a background image of a specific color (such as a white background or a blue background).
[0029]
This specific video chroma IC receives color signals (R, G, R, G, and R) as elements for forming a white background image when first operation instruction data including white display is input from the control microcomputer 1. B) is generated and output.
[0030]
The above specific video chroma IC is operated by giving operation instruction data indicating a display color or luminance according to the state (“High”, “Low”) of each bit of serial data composed of 1 byte (8 bits). Can be used.
[0031]
As the specific video chroma IC, a known one can be used. That is, when 1-byte serial data including a specific one color in data is input, a video chroma IC (specific video chroma IC) that operates to display a specific one-color background image on a cathode ray tube is provided by a microcomputer. It is known in the field of controlled television receivers. In practicing the present invention, such a known specific video chroma IC can be used.
[0032]
Further, the white background display circuit 2 includes an ACL (auto contrast limiter). When the white background display circuit 2 is configured by the specific video chroma IC, a specific video chroma IC having an ACL can be used.
[0033]
The ACL operates to suppress the luminance when displaying an image on the cathode ray tube 7 to a range lower than a certain upper limit. That is, the ACL controls the anode current of the cathode ray tube 7 so as not to exceed a preset value.
[0034]
If it is not desired to suppress the luminance displayed on the cathode ray tube 7, the luminance suppressing operation by the ACL is relaxed. If the brightness suppression operation by the ACL is relaxed, the brightness (brightness) displayed on the screen of the cathode ray tube 7 can be maximized, and the contrast of the screen can be maximized.
[0035]
The mitigation of the luminance suppression operation by the ACL is controlled by the ACL mitigation circuit 15. That is, when the second operation instruction data is input from the control microcomputer 1 to the ACL mitigation circuit 15, the ACL mitigation circuit 15 controls the operation of the ACL, and the luminance suppression operation by the ACL is reduced.
[0036]
Further, by inputting the third operation instruction data to the white background display circuit 2, the brightness of displaying an image on the cathode ray tube 7 can be maximized. Further, by inputting the fourth operation instruction data to the white background display circuit 2, the contrast for displaying an image on the cathode ray tube 7 can be maximized.
[0037]
The color signal amplification circuit 3 outputs color signals (R, G, B) to the cathode ray tube 7 for operating the cathode ray tube 7 to display a white background image. When a color signal for displaying a white background image output from the white background display circuit 2 is input to the color signal amplification circuit 3, the color signal amplification circuit 3 appropriately amplifies the color signal and outputs it to the cathode ray tube 7.
[0038]
The high voltage generation circuit 5 outputs a high voltage applied to the anode of the cathode ray tube 7. A high voltage output from the high voltage generating circuit 5 is applied to the anode of the cathode ray tube 7 to accelerate the electron beam, and the accelerated electron beam collides with the screen of the cathode ray tube 7 and emits light to form an image. .
[0039]
In displaying an image on the screen of the cathode ray tube 7, the electron beam is scanned along the vertical and horizontal directions of the screen based on the color signal input from the color signal amplifier circuit 3, and the electron beam is scanned. An image is formed by the locus on the screen. Each pixel on the screen of the cathode ray tube 7 emits a specific color based on the information of the input color signal.
[0040]
The electron beam is scanned vertically in the vertical direction sequentially from top to bottom (or from bottom to top) by a magnetic field generated by a vertical deflection coil (not shown). The electron beam is sequentially scanned in the horizontal direction from left to right (or right to left) by a magnetic field generated by a horizontal deflection coil (not shown).
[0041]
The cathode ray tube display device shown in FIG. That is, power for operating the control microcomputer 1, the white background display circuit 2, the color signal amplifying circuit 3, the high voltage generating circuit 5, the cathode ray tube 7, and the like is supplied from the power supply circuit 8.
[0042]
The power supply circuit 8 is configured to be supplied with required power from an external power supply (not shown). The power supply circuit 8 is controlled by the control microcomputer 1 to be turned on (ON) and turned off (OFF).
[0043]
The cathode ray tube display device described above includes other known members and circuits not shown in FIG. 1 for general operation as a television receiver. That is, the display device includes an on-screen display circuit (OSD circuit) for displaying characters and the like on the screen of the cathode ray tube 7 based on a video signal representing a character, a normal video, and the like, a contrast adjustment circuit, a luminance adjustment circuit, and the like. . These on-screen display circuits and the like are known circuits provided in a television receiver controlled by a control microcomputer.
[0044]
An example of operating the above-described cathode ray tube display of the present invention will be described with reference to FIG. FIG. 2 is a flowchart showing a procedure for operating the cathode ray tube display device.
[0045]
First, the operation key 11 is operated, and the power is turned on by operating the power key 11a. Thereby, the operating power is supplied from the power supply circuit 8 to each unit. Then, the operation of the control microcomputer 1 is started, and the control microcomputer 1 starts executing a power supply stop routine (S1).
[0046]
Then, it is detected whether or not the control microcomputer 1 has been operated to turn off the power by the power key 11a (S2). It waits until an operation to turn off the power is detected (S2, N). Then, when the operation of turning off the power is detected (S2, Y), the control microcomputer 1 outputs the second operation instruction data, and relaxes the ACL luminance suppression operation of the white background display circuit 2 (S3).
[0047]
Next, according to a white back instruction for displaying a white background image on the screen of the cathode ray tube 7 (S4), first operation instruction data containing the display of the white background image is output from the control microcomputer 1, and One operation instruction data is input to the white background display circuit 2. As a result, a white background image is displayed on the screen of the cathode ray tube 7.
[0048]
Next, third operation instruction data containing the content of maximizing the brightness of the screen of the cathode ray tube 7 is output from the control microcomputer 1 and input to the white background display circuit 2. Thereby, the brightness for displaying the white background screen is maximized (S5).
[0049]
Next, fourth operation instruction data containing the content of maximizing the contrast of the screen of the cathode ray tube 7 is output from the control microcomputer 1 and input to the white background display circuit 2. Thereby, the contrast for displaying the white background screen is maximized (S6).
[0050]
Then, the control microcomputer 1 controls the power supply circuit 8 to turn off the power (S7), and terminates the execution of the power supply stop routine (S8). Thus, the supply of power to each part of the cathode ray tube display device is stopped.
[0051]
According to the above-described procedure, when an operation of turning off the power is detected, a white background image is displayed on the screen of the cathode ray tube 7 by the white back instruction (S4), and thereafter, the power is turned off. Thus, the power supply can be turned off after discharging the electric charge stored in the cathode ray tube 7 as an anode current.
[0052]
As a result, it is possible to prevent spots from remaining when the power is turned off while the electric charges stored in the cathode ray tube 7 remain.
[0053]
In the above procedure, when displaying the white background image, the brightness is maximized (S5), and the contrast is maximized (S6). As a result, it is possible to prevent charges from remaining, and it is possible to more reliably prevent spots from remaining.
[0054]
Thereby, it is possible to prevent a viewer from having an unpleasant impression due to a spot remaining when the power is turned off. Further, when a spot remains, even though the power is turned off, only the central portion of the cathode ray tube continues to shine thinly, so that a screen burn-in or the like may occur and the screen may be damaged. By preventing the spot remaining according to the present invention, it is possible to prevent screen burning and prevent damage to the screen.
[0055]
According to the cathode ray tube display device of the present invention, a circuit for preventing the occurrence of residual spots can be configured by connecting the control microcomputer 1, the white background display circuit 2, and the data communication bus 10, and has a simple configuration. It can be.
[0056]
Further, when the white background image is displayed on the cathode ray tube 7, the control microcomputer 1 can output the operation instruction data including the display color to the white background display circuit 2, thereby simplifying the control procedure. be able to.
[0057]
Further, according to the present invention, as described above, the white background display circuit 2 is directly connected to the control microcomputer 1 via the communication bus 10. Then, the control microcomputer 1 directly gives the operation instruction data to the white background display circuit 2 and controls the white background display circuit 2 to display a white background image.
[0058]
This prevents a time delay from outputting the operation instruction data from the control microcomputer 1 to operating the cathode ray tube 7 based on the operation instruction data, and promptly controls the cathode ray tube 7 to display a white background image. It can be carried out.
[0059]
Thus, the time from when the viewer turns off the power by operating the power key 11a until the power is actually turned off and stopped by the power supply circuit 8 can be shortened.
[0060]
As a result, it is possible to shorten the time from when the viewer turns off the power while watching the screen of the cathode ray tube 7 until the screen completely stops. Thereby, a pleasant impression can be given to the viewer without being unpleasantly waiting until the screen completely stops after the viewer turns off the power.
[0061]
Further, according to the cathode ray tube display of the present invention, as described above, the control for displaying the white background image on the cathode ray tube 7 can be performed quickly, so that the control for displaying the white background image on the cathode ray tube 7 is easy. .
[0062]
The above description based on FIGS. 1 and 2 shows an example in which an I2C communication bus is used as the data communication bus 10 and the control microcomputer 1 transmits operation instruction data to the white background display circuit 2 based on the I2C bus communication. I explained it.
[0063]
The present invention can be implemented by a system based on bus communication other than I2C bus communication. Further, the present invention can be carried out based on a method of communicating digital data even if it is not a bus communication.
[0064]
That is, in implementing the cathode ray tube display device of the present invention, the control microcomputer and the white background display circuit are directly connected via a digital data transmission line capable of communicating digital data, and the operation instruction as digital data is issued from the control microcomputer. It is sufficient that the cathode ray tube 7 can display a white background image by transmitting the data to the white background display circuit.
[0065]
【The invention's effect】
As described above, according to the cathode ray tube display device of the present invention, the configuration of the circuit can be simplified in preventing the occurrence of the remaining spot. Further, the control procedure for displaying the white background image can be simplified.
[0066]
In displaying a white background image on the cathode ray tube, the operation of the cathode ray tube can be quickly controlled. Thus, the time from when the power is turned off to when the power is actually turned off and the operation is stopped can be shortened.
[Brief description of the drawings]
FIG. 1 is a block diagram of a cathode ray tube display device according to one embodiment of the present invention.
FIG. 2 is a flowchart showing a procedure for operating a cathode ray tube display device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Control microcomputer 2 White background display circuit 2a Data input terminal 2b Clock input terminal 3 Color signal amplification circuit 5 High voltage generation circuit 7 Cathode ray tube 8 Power supply circuit 10 Data communication bus 10a Data transmission path 10b Clock transmission path 11 Operation key 11a Power key 12 Operation determination means

Claims (3)

A cathode ray tube that performs an operation of displaying an image, a control microcomputer that controls start and stop of the operation of the cathode ray tube according to an operation of turning on and off a power supply, and a white background that displays a white background image on the cathode ray tube And a display circuit,
The white background display circuit is connected to the control microcomputer by a digital data transmission path, and when operation instruction data indicating that the display is to be white is input from the control microcomputer, the white background is displayed on the cathode ray tube. It is configured to display a background image,
When the power-off operation is performed, the control microcomputer outputs the operation instruction data to the white background display circuit and causes the cathode ray tube to display a white background image, and then stops the operation of the cathode ray tube. By
A cathode ray tube display device configured to prevent spots from remaining on the cathode ray tube. The digital data transmission path is an I2C communication bus including a data transmission path and a clock transmission path,
2. The cathode ray tube display device according to claim 1, wherein the control microcomputer can detect that the white background display circuit has received the operation instruction data. The white background display circuit includes a luminance suppressing unit that suppresses luminance of a cathode ray tube displaying an image,
3. The cathode ray tube display device according to claim 1, wherein, when displaying a white background image on the cathode ray tube by the white background display circuit, an operation of suppressing the luminance by the luminance suppressing unit is relaxed. 4. .

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