JPH01251095A - Crt display device - Google Patents

Abstract

PURPOSE:To decrease the radiation of an unnecessary electromagnetic wave from the CRT tube surface by limiting a luminescent point display range on the CRT tube surface in accordance with an instruction from an input means and setting only an area on the CRT tube surface required for a user to the luminescent point display range. CONSTITUTION:In case when it is desired to limit a luminescent point display range to only an area required for a user, the user operates a joy stick 16. A bias controller 18 receives input data from the stick 16 through a joy stick interface 17, determines the luminescent point display range, based on position designating information from the joy stick 16, and inhibits a luminescent point display by controlling a luminance adjusting amplifier 13, in case when a raster scan position becomes an outside of the luminescent point display range. In such a way, the luminescent point display range is limited in accordance with an instruction from an input means, and only an area on the CRT 11 tube surface required for the user becomes the luminescent point display range, therefore, the radiation of an unnecessary electromagnetic wave from the CRT 11 tube surface can be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a CRT display device in which a bright spot display range on a CRT tube surface can be limited.

(Prior Art) In a conventional CRT display device, the entire tube surface of a CRT (cathode ray tube) (CRT tube surface) is subject to bright spot display. Therefore, a user who handles a processing device such as a terminal device equipped with this type of CRT display device is constantly exposed to unnecessary electromagnetic wave radiation from the entire surface of the CRT tube.

(Problems to be Solved by the Invention) As mentioned above, in the conventional CRT display device, C.
Since the entire RT tube surface was subject to bright spot display, there was a problem in that the user was at risk of receiving unnecessary electromagnetic wave radiation from the entire CRT tube surface.

Therefore, an object of the present invention is to reduce the electromagnetic wave radiation from the CRT tube surface that is received by the user of the CRT display device.

[Structure of the Invention] (Means for Solving the Problems) The present invention includes an input means for instructing a bright spot display range on a CRT tube surface, a raster scan position with respect to the CRT tube surface, and a raster scan position on the CRT tube surface. The present invention is characterized by further comprising a control means for suppressing display of a bright spot at the same position when the bright spot is outside the bright spot display range designated by the input means.

(Function) According to the above configuration, since the bright spot display range is limited according to the instruction from the input means, the CR required for the user is
By setting only the area on the T-tube surface as the bright spot display range, CR
It becomes possible to reduce unnecessary electromagnetic wave radiation from the T-tube surface.

(Embodiment) FIG. 1 shows a block configuration of a CRT display device according to an embodiment of the present invention. In the same figure, 11 is CR
T (cathode ray tube), 12 is an electron gun that emits an electron beam to make the tube surface (phosphor screen) of the CRT 11 emit light, 1
3 to determine the intensity of the electron beam (therefore C
Electron gun 1 (for determining the brightness on the RTII tube surface)
This is a brightness adjustment amplifier that sets the second bias voltage (brightness adjustment bias voltage). The brightness adjustment amplifier 13 is configured to set a brightness adjustment bias voltage in accordance with the video signal when it is not subjected to OFF control from a bias controller 18, which will be described later. 14 is an electron gun 12
A deflection plate 15 is a deflection clock circuit that outputs a deflection voltage sweep clock (deflection clock) for the raster scan to the deflection plate 14.

Reference numeral 16 denotes an input means used for specifying a position, for example, a joystick. In this embodiment, the joystick 1B is used to input an instruction for the bright spot display range on the screen of the CRT II. 17 is a joystick interface that is an input interface for the joystick TE; 18 is a joystick interface that determines the bright spot display range based on the position designation information of the joystick TE that is input through the interface 17, and determines the bright spot display range when the raster scan position is outside the bright spot display range. This is a bias controller that controls the brightness adjustment amplifier 13 to prohibit bright spot display when the following occurs.

Next, the operation of the configuration shown in FIG. 1 will be described with reference to the flowchart shown in FIG. 2 and the diagram shown in FIG. 3 showing an example of correspondence between joystick operations and bright spot display ranges.

Users of the CRT display device shown in Figure 1 must use the CRTI
If the user wishes to limit the bright spot display range of I to only the area required by the user, operate the joystick 16. The bias controller 18 receives input data from the joystick 16 via the joystick interface 7 (step SL), then analyzes the input data, and based on this analysis result and the current bright spot display range, the user The required bright spot display range is determined (step 82).

FIG. 3 shows an example of this determination method. Here, when the joystick 16 is operated upward while the area indicated by reference numeral 21 on the screen of the CRT 11 is the bright spot display range, the bright spot display range (the size remains unchanged). ) When the joystick 1B is moved upward as shown by 22 and the joystick 1B is operated downward, the bright spot display range is moved downward as shown by 23 (while keeping the size unchanged). Similarly, when the joystick 16 is operated to the left while the area 21 is the bright spot display range, the bright spot display range is expanded up and down as shown by the reference numeral 24, and the joystick I6 is moved to the right. When operated, the bright spot display range is reduced as shown by reference numeral 25.

Now, when the bias controller 18 determines the latest bright spot display range according to the position designation input from the joystick IB operated by the user, the bias controller 18 determines the latest bright spot display range based on the deflection clock generated from the deflection clock circuit 15. The appearing screen scan position (current bright spot address) is calculated (step 813).

Next, the bias controller 18 compares the appearing screen scan position with the bright spot display range determined in step S12, and determines whether the appearing screen scan position (bright spot address) is within the current bright spot display range. Check (step S14).

When the bias controller 18 determines in step S14 that the appearing screen scan position is not within the bright spot display range, the bias controller 18 sets the brightness adjustment amplifier 13 (bias application operation to the electron gun 12) to 0FFL.

(Step 515), returning to step S13. This suppresses electron beam emission from the electron gun 12, thereby suppressing light emission at (the phosphor of) the corresponding raster scan position on the tube surface of the CRT 11, and preventing electromagnetic wave radiation from the same position. On the other hand, if it is determined that the current scan position is within the bright spot display range, the bias controller 18 sets the brightness adjustment amplifier 13 to 0NL (step 51B) and returns to step S13. In this case,
Since a bias voltage based on the video signal is applied from the brightness adjustment amplifier 13 to the electron gun 12, an electron beam is emitted from the electron gun 12 according to this bias voltage, and the CRT
Corresponding raster scan position (phosphor) on the tube surface of ll
emits light.

The above operations are performed on the entire surface of the CRT II screen in synchronization with the raster scan, so that a bright spot is displayed on the screen of the CRT II, which is determined according to the position designation input from the joystick 1B operated by the user. Bright spot display is performed only within the bright spot display range, and bright spot display is suppressed outside the bright spot display range. Therefore, unnecessary electromagnetic wave radiation from the CRT 11 is reduced compared to the case where the entire screen of the CRT II is displayed. Limiting the bright spot display range on the screen of the CRT 11 described above to the area requested by the user is useful when displaying a part of the screen (for example, during demonstrations or presentations using the CRT display device). It can also be applied when you want to particularly emphasize the content.

In the above embodiment, a joystick is used as an input means for specifying the bright spot display range, but other position specifying means such as up/down/left/right cursor movement keys, a mouse, etc. may also be used. It is also possible to specify the position of the bright spot display range using two points, for example, the upper left end and the lower right end. Furthermore, a well-known eye-tracking device that tracks the user's line of sight is used as a bright spot display range specifying means, and only the area corresponding to the periphery of the line of sight on the CRT screen is automatically illuminated according to the tracking results of this eye-tracking device. It is also possible to display points.

[Effects of the Invention] As described in detail above, according to the present invention, the bright spot display range on the CRT tube surface is limited according to the instruction from the input means, so that the bright spot display range on the CRT tube surface that is necessary for the user can be By setting only the area as the bright spot display range, unnecessary electromagnetic wave radiation from the CRT tube surface can be reduced. Furthermore, since the bright spot display range can be limited, it is also possible to extract a portion to be emphasized from the screen during a presentation using a CRT or projector.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing an embodiment of a CRT display device according to an embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation, and FIG. 3 is a diagram showing the relationship between joystick operation and bright spot display range. It is a figure showing an example of correspondence. 11...CRT (cathode ray tube), 12...electron gun,
13... Brightness adjustment amplifier, 15... Deflection clock circuit, 16... Joystick (input means), 18...
...Bias controller (control means). Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A CRT display device equipped with a cathode ray tube includes an input means for instructing a bright spot display range on the tube surface of the cathode ray tube, and a raster scan position with respect to the cathode ray tube is detected, and this detected position is detected from the input means. A CR characterized in that it is equipped with a control means for suppressing display of a bright spot at the same position when the bright spot is outside the designated bright spot display range.
T display device.