JPS6120624Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a CRT display device, and more particularly to a device having a function of automatically compensating for errors in a deflection system. CRT display devices are widely used in various fields in addition to terminal devices for computer systems. By the way, the conventional bright spot position adjustment system for this type of folding is completely open loop, and is not configured to detect the position of the bright spot and automatically set it to the correct display position. That is, the deflection system and the electron gun system are only adjusted as necessary, which requires a relatively large number of man-hours. In order to solve these drawbacks, the present invention
The position of the bright spot displayed by the CRT is detected during operation, including mechanical errors in the CRT installation, errors in the deflection system, errors due to changes over time, external magnetic fields, etc., and the position is automatically adjusted. This is what I did. In other words, the present invention two-dimensionally arranges at least three light-receiving mechanisms for detecting the CRT's bright spots at predetermined positions on the outer periphery of the CRT's effective screen, and sets the deflection system of the CUT to correspond to the position of each light-receiving mechanism. The present invention is characterized in that a compensation signal related to the output signal of each light-receiving mechanism is added to the reference signal, and a bright-spot position error is compensated for by each light-receiving mechanism detecting a bright spot. This makes it possible to adjust the bright spot position using a normal CRT without any special processing on the CRT itself. Hereinafter, a detailed explanation will be given using the drawings. FIG. 1 is an explanatory diagram showing the main parts of an example of the device according to the present invention, in which a is a partially sectional plan view and b is a partially sectional plan view.
is a front view, and c is a partially enlarged sectional view. In the drawings, 1 is a CRT, 2 is a front frame, 3 is a mounting panel, 4 is a mounting band, 5 is a spacer, and 6 is a light receiving mechanism. In the CRT 1, 11 is a fluorescent surface. this
A mounting band 4 having an L-shaped cross section is attached to the outer periphery of the CRT 1. CRT1 has mounting band 4
It is attached to the mounting panel 3 via. The front frame 2 is attached via a spacer 5 so as to cover a part of the outer periphery of the effective screen of the CRT 1 and a part of the inner periphery of the mounting window of the mounting panel 3. At least three light receiving mechanisms 6 for detecting bright spots of the CRT 1 are two-dimensionally embedded in a portion of the front frame 2 facing the outer periphery of the effective screen of the CRT 1.
These light receiving mechanisms 6 are constituted by optical means such as a lens 61, a reflecting mirror 62, a photo cell 63, etc., but are not limited to such a configuration. Note that the photocell 63 is shown in FIG.
A four-quadrant separated type as shown in b is desirable, but a single type without separation may also be used. Here, the light receiving mechanism 6 only needs to be located inward from the inner surface of the front frame 2 by at least a distance d that is longer than the thickness t of the front glass of the CRT 1, and the influence of external light can be effectively suppressed. can. FIG. 3 is a block diagram showing an example of a circuit for processing the output signal of the photocell shown in FIG. 2, and shows one light receiving mechanism 6. In FIG. Third
In the figure, MPX is a multiplexer, A/D is a converter that converts analog signals to digital signals,
MPU is a processor. Each photocell~
The output signal of is Amplifier A → Multiplexer MPX
→It is added to the processor MPU via the converter A/D path. Note that the multiplexer MPX has
The output signals of the plurality of light receiving mechanisms 6 are respectively applied via amplifiers A, which are not shown. Further, in this case, by providing a multiplexer between each photocell and the amplifier A, the amplifier can be shared by a plurality of light receiving mechanisms, and the configuration can be simplified. Here, when measuring a stationary, unmodulated bright spot, it is sufficient to detect the difference between when the beam is ON and when the beam is OFF digitally using DC, and when measuring a bright spot whose brightness is modulated, it is sufficient to detect the difference between when the beam is ON and when the beam is OFF. The amplitude can be detected by coupling. Thereby, the influence of external light can be practically ignored. FIG. 4 is a block diagram showing an example of a signal processing circuit in the case of random scan, and parts equivalent to those in FIG. 3 are given the same reference numerals. In Figure 4, MPX2 and MPX3 are multiplexers, D/
A is a converter that converts digital signals to analog signals, CTL is a control circuit, SW1 is a switch circuit,
Ax, Ay, Aθ are amplifiers, x, y are deflection yokes,
θ is a trace rotating coil, Vx and Vy are image signal input terminals, and ±Vs, Vsx and Vsy are reference signal input terminals. Multiplexer MPX2 outputs the reference signal ±Vs
is sent to switch circuit SW1. converter D/A
converts the digital signal sent from the processor MPU into an analog signal and sends it to the multiplexer.
Send to MPX3. Multiplexer MPX3 is
The analog signal applied from the converter D/A is sent to the control circuit CTL and the amplifier Aθ. The control circuit CTL controls the gain and offset of amplifiers Ax and Ay. The switch circuit SW1 alternately switches between the reference signal sent from the multiplexer MPX2 and the image signal applied to the input terminals Xx and Vy, and sends them to the amplifiers Ax and Ay. here,
The detected position is defined as (±1, ±1) on the x and y axes, and a reference signal of ±Vs is added from the multiplexer MPX2. As a result, a signal corresponding to the position error is added to the multiplexer MPX1. Therefore, after adjusting the current applied to the rotating coil θ in advance so that the rotational component becomes zero, the offset and gain of each amplifier Ax and Ay are adjusted so that the common-mode component and differential component in each of the x and y axes become zero. adjust. By repeating this process several times, the error amount converges to zero. Note that when the rotating coil θ is used, x,
y between both channels

Crosstalk may be provided to impose the matrix [Formula]. Furthermore, when input signals to the amplifiers Ax and Ay of each axis are applied via the converter D/A as in this embodiment, all these arithmetic operations can be performed at the digital signal stage. Further, although it is desirable to perform such an error compensation operation in between each refresh, since the device is generally considered to be stable, it may be performed only during maintenance and inspection. FIG. 5 is a block diagram showing the main parts of an example of a signal processing circuit in the case of raster scan, and FIG.
Parts equivalent to those in the figure are given the same reference numerals. In FIG. 5, PG is a pattern signal generator, G is an AND gate, SW2 is a switch circuit, and IT1 and IT2 are boxcar integrators or interval integral hold circuits. The generator PG sends out a pattern signal for causing the CRT 1 to shine at a predetermined position facing the light receiving mechanism 6 disposed around the outer periphery of the effective screen. This pattern signal can be added at the same time even while the main target image signal is being displayed on the screen of the CRT 1 surrounded by the front frame 2. That is, it is sufficient to apply blanking around the relevant position and unblanking only the relevant position. By doing this, that part will always shine at the field rate, so the light receiving mechanism 6
can monitor its position at all times. An x selection signal and a y selection signal are applied to the AND gate G from the generator PG. Then, the switch circuit SW2 is turned on only when both signals match. As a result, the output signal of the light receiving mechanism 6 is transmitted to the integrator IT1 only when the beam reaches a predetermined position.
It will be added to IT2, and the influence of external light can be removed. Note that the influence of external light can also be removed by controlling whether or not these bright spots at predetermined positions are illuminated, and by determining the difference between when they are illuminated and when they are not illuminated. In addition, in Fig. 5, a generator is used as a control signal for the switch circuit SW2.
Although an example using x, y selection signals sent from the PG is shown, an unblanking signal for illuminating a predetermined position may also be used. In addition, in the case of raster scan, dedicated optimized high-efficiency deflection circuits are often used for both the x and y axes.
It is generally difficult to provide crosstalk between y. Therefore, as in the embodiment of FIG.
The rotation component can be processed by the rotating coil θ, and the configuration can be simplified. FIG. 6 is a block diagram showing the main parts of another example of a signal processing circuit in the case of random scan,
Components equivalent to those in FIG. 4 are given the same reference numerals. In Figure 6, OSC is a perturbation oscillator, SD1, SD
2 is a synchronous detector, and IT3 and IT4 are integrators or low-pass filters. When position detection is performed using a single photocell, the beam can be perturbed. By the way, when a bright spot is detected using a single photocell, the detection current regarding the x and y positions of the bright spot exhibits a single peak, and its base is gentle and monotonous. Therefore, by simply repeatedly perturbing the beam and detecting the phase of the fundamental wave component, matching of the centers can be detected.
That is, the beam is moved to a position facing a predetermined light receiving mechanism while swinging in a minute circle, and the output signal of the photocell is converted into the output of amplifier A by the output signals sin wt and cos wt of the perturbation oscillator OSC. By performing synchronous detection, error signals x' and y' related to both the x and y axes can be obtained. The bright spot position error can be compensated for by feeding back through the digital system as described above after integration so that these error signals x' and y' converge to zero. As described above, according to the present invention, a CRT display device having a function of automatically compensating for errors in the deflection system can be realized, and is suitable for terminal devices of computer systems, display devices of measuring instruments, etc.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the main parts of an example of the device according to the present invention, Fig. 2 is an explanatory diagram showing the arrangement of an example of the photocell used in the invention, and Fig. 3 is an explanatory diagram of the circuit for processing the output signal of the photocell. 4 is a block diagram showing an example of a signal processing circuit for random scan, FIG. 5 is a block diagram showing an example of a signal processing circuit for raster scan, and FIG. 6 is a block diagram showing an example of a signal processing circuit for random scan. FIG. 3 is a block diagram showing the main parts of another example of the signal processing circuit in the case of FIG. 1...CRT, 2...Front frame, 3...Mounting panel, 4...Mounting band, 5...Spacer, 6...
Light receiving mechanism.

Claims (1)

[Scope of utility model registration request] At least three light-receiving mechanisms for detecting the CRT's bright spots are two-dimensionally arranged at predetermined positions on the outer periphery of the CRT's effective screen, and a reference signal corresponding to the position of each light-receiving mechanism is added to the CRT's deflection system. A CRT display device characterized in that a compensation signal related to the output signal of each light-receiving mechanism is added to the output signal of each light-receiving mechanism so that each light-receiving mechanism detects a bright spot to compensate for a bright spot position error.