JPS5993492A - Display unit using cathode ray indicator tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a raster scan type cathode ray display tube (hereinafter referred to as C
The present invention relates to a display device using an RT (referred to as RT).

Conventionally, an electron beam that is energized and scanned by a video signal is applied to the fluorescent film of the CRTR7 display film.
A display device such as a television that displays characters, figures, pictures, etc. on a display surface, or a light spot on a fluorescent film is irradiated onto a photosensitive paper that is drawn out at a constant speed, and characters or figures are displayed on a photoreceptor. There are display devices, such as facsimiles, for obtaining images, pictures, etc.

In the CRTs used in these display devices, the deflection and scanning of electron beams may not be performed properly due to some reason, such as changes in circuit constants due to aging or the effects of temperature changes. In this case, the resulting image becomes distorted, and it becomes impossible to obtain a high-quality image.

Furthermore, if the fluorescent film is configured to display colored light, color shift may occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a display device in which the electron beam of a CRT is always deflected normally, without distortion, and in which a high-quality image can be obtained.

The device according to the present invention has a light-receiving surface composed of photoelectric elements at two locations sandwiching a region of a CRT display surface, and a raster image sensor that outputs a signal corresponding to the position of a light spot irradiated onto the light-receiving surface. A detection means is installed, and the signal obtained from the detection means is processed to detect the scanning status of the raster, and the signal indicating the scanning status of the raster is used to control the electron beam deflection circuit and/or the light intensity of the raster. It is characterized by the fact that

FIG. 1 is a block diagram showing an example of a device according to the present invention. Here, VicRT is used in facsimiles and printers, and the electron beam (raster) has a vertical sweep speed that is much faster than the horizontal sweep speed on the CRT screen, and the electron beam (raster) moves up and down as shown by the arrow. Shows what is being scanned in the direction. In the figure, 1 is a CRT
, 2 is a coil for electron beam deflection of this CRT, 3 is C
On the RT display surface, reference numeral 4.5 denotes raster detection means installed so as to sandwich the three CRT display areas. One of the raster detection means 4 includes a condensing lens 40 that passes through a starting light spot SPS 6 that shines at the starting point position of the raster, and four (fourth-divided) photoelectric elements 41. It is composed of 42, 43, and 44. The other raster detection means 5V'i, the end point light spora that shines at the end point position of the raster) A condensing lens 50 through which the EPS'i passes, and four (4-division) photoelectric elements that receive the light spot that has passed through this lens 50. It is composed of 51.52° and 53.54°. 45 is a 4-channel amplifier that amplifies the signals 81 to S4 from the photoelectric elements 41 to 44; 55 is the photoelectric element 51 to 44;
A 4-channel amplifier that amplifies the signals E, ~E4 from 54, and 6 is an operation that uses the signals from each of these 4-channel amplifiers as input to calculate the raster position and raster brightness i). It is a circuit. 7 is a sweep circuit for vertical and horizontal sweeping of the electron beam, and 8 is a two-axis control circuit for controlling raster brightness (two axes), both of which receive signals from the arithmetic circuit 6. 9 is a signal generation circuit that generates various control signals and clock pulses, including an arithmetic circuit and a sweep circuit 7.
It outputs control signals and synchronization pulses to the z-axis control circuit 8.

The operation of the apparatus configured as described above will now be explained with reference to the waveform diagram of FIG. In FIG. 2, only the vicinity of the end point of the horizontal sweep and the vicinity of the next starting point are representatively shown.

The sweep circuit 7 is connected from the signal generation circuit 9 to FIGS.
Receiving the vertical synchronizing pulse VT and horizontal synchronizing pulse HT as shown in (c), the deflection coil 2 receives the vertical axis sweep sawtooth wave V8 and the horizontal axis sweep sawtooth wave H8 as shown in (b) and (b). and scan the electron beam on the CRT display surface 3. As a result, raster scanning is performed on the CRT display surface 3 as shown by the arrow.

The Z-axis control circuit 8 includes an image signal pcs and a signal generation circuit 9
A brightness signal CG as shown in FIG. 2 (e) is applied to the beam current control grid of the CRTl. In this luminance signal CG, VBLK is a vertical blanking pulse, EPBLK is a horizontal sweep end point side blanking pulse,
HBLK is a horizontal blanking pulse, 5PBLK ij is a horizontal sweep starting point side blanking pulse, and the level of each of these blanking pulses is below the cutoff level of the video signal, and during this period, the FicRT display screen 3 rasters are not displayed.

EP is the end point positioning pulse that occurs just before the end (end point) of the horizontal axis sweep, and sp is the start point positioning pulse that occurs at the same time as the start (start point) of the horizontal axis sweep.The levels of these pulses are both the maximum of the video signal. be above the level,
At this point, the end point positioning light spora is placed on the CRT display surface 3)
EP8 and origin positioning light spoiler) Display SPB.

Optical spora displayed on the upper left corner of CRT display surface 3) 8
The PS passes through the condensing lens 40 and is received by the photoelectric elements 41 to 44 which are divided into four parts and have uniform sensitivities, and the light spot displayed on the lower right corner of the CRT display surface 3) The light passes through the lens 50 and is received by photoelectric elements 51 to 54, which are also divided into four parts and have uniform sensitivities.

Here, each of the photoelectric elements 41 to 44 (51 to 54) outputs each output signal S, to S4 when the light spot SPS (gPs) is on the CR7 display surface 3 and displayed at a correct predetermined position. (E, ~E4) are arranged so that they are equal.

FIG. 3 is a waveform diagram showing the position of the displayed light spot and the form of the signals from each of the photoelectric elements 41 to 44 (51 to 55). That is, the displayed light spot) 5PS (
KPS) scans the correct predetermined position from top to bottom, the center of the real image of the light spot irradiated onto the light receiving surface passes through between photoelectric elements 41.44 and 42.43,
Since the same amount of light is given to each element, the signal S from each element,
~S4 becomes the sequence shown in (a). Hereinafter, signals S and -S4 from each element when the displayed light spot is shifted from a predetermined position, vertically, and horizontally are as shown in (b) to (e), respectively.

The arithmetic circuit 6 receives the signals S, ~S4, and E, ~E4 from the 4-channel amplifier 45.55, and inputs the signals S, ~S4, and E, ~E4 from the 4-channel amplifier 45.55. 1 Obtain the peak values of each signal 81 to S4 and E, to E4 (each sample hold circuit is shown in Fig. 2).
At the timings shown in (1) to (2), each data is held) and predetermined calculations for detecting the raster scanning status are performed, for example, calculations shown in equations (11 to (6)).

Δsv-□ Square/(3) S ΔH-ΔEH-Δaxis ・・・・・・・・・f
51ΔV−ΔEv−ΔSv ・・・・・・
...(6) Tasoshi, S, ~S4. E, ~E4 is
Peak values of the signals from the photoelectric elements 41 to 44 and 51 to 54, respectively ΔSH: Deviation from the specified position of the horizontal sweep starting point ΔEH: Deviation from the specified position of the horizontal sweep end point ΔSv; Deviation from the specified position of the vertical sweep starting point Deviation ΔEv: Vertical sweep Deviation from the vertical sweep viewpoint position ΔH: Deviation amount of horizontal sweep length ΔV: Deviation amount of vertical sweep length Ks: Sensitivity coefficient K at the starting point position. =Sensitivity coefficient at the end point position (Ks, , and are both determined by the phosphor, beam voltage and current.) The calculation circuit 6 uses the calculation results of the above-mentioned equations (11 to (6)) to the sweep circuit 7. Here, the vertical axis sweep sawtooth wave VS and the horizontal axis sweep sawtooth wave Hs are output to eliminate each deviation.
control. That is, the deviation at the starting point can be controlled by changing the DC bias applied to the deflection coil 2, and the amplitude error can be controlled by increasing or decreasing the power supply voltages of the vertical and horizontal sweep sawtooth wave oscillators. I can do it. Also, from the calculation circuit 6, a light spot) 8P
8 or a signal related to the brightness of EPB (for example, a signal obtained by calculating s, + s2 + s, + s4 in the arithmetic circuit 6) 'tl- is obtained, and this is sent to the two-axis control circuit 8.
The brightness of the light spot (light intensity) is controlled so that it reaches a specified value. This light 1: control is not necessarily necessary for positioning.

In the above embodiment, the raster detection means 4.5 is exemplified using a photoelectric element divided into four parts, but when controlling only either horizontal or vertical sweep, this raster detection means f' It is also possible to use a light beam 'w1 divided into two parts. Further, for this purpose, other means for detecting the two-dimensional light spot position, such as an optical semiconductor device detector (PAD), may be used. Also, former spot 8PS, E
P8 is designed to shine on both sides of the front of the CR'r screen, but these light spots are
It may also be made to glow on the side. Further, here, a case where the raster is scanned in the vertical direction is exemplified, but the raster may be scanned in the horizontal direction.

As described above, according to the apparatus according to the present invention, deflection of an electron beam, that is, raster scanning, can always be performed normally, and high-quality images can be obtained.

[Brief explanation of drawings]

FIG. 1 is a configuration block diagram showing an example of a device according to the present invention, FIG. 2 is an operating waveform diagram thereof, FIG. 3 is a waveform diagram showing the form of a signal of a photoelectric element in the device shown in FIG. 1, and FIG. FIG. 2 is a connection diagram showing an example of a sample and hold circuit in the arithmetic circuit in the device of FIG. 1;

Claims (2)

[Claims] (1) In a display device using a raster-scan cathode ray display tube whose display surface is made of a fluorescent film, a light receiving device composed of photoelectric elements is installed at two locations sandwiching the display surface area of the cathode ray display tube. a raster detection means for outputting a signal related to the spot light position on the surface; and a raster scanning state of the cathode ray display tube is detected by inputting signals from the raster detection means and processing each of these signals. An arithmetic circuit and circuit means for respectively displaying a spot for positioning a sweep start point and a spot for positioning a sweep end point at predetermined positions of the cathode ray display tube are provided, and the sweep conditions of the cathode ray display tube are controlled by signals from the arithmetic circuit. A display device using a cathode ray display tube, characterized in that: (2) A display device using a cathode ray display tube according to claim 1, wherein the brightness of the cathode ray display tube is controlled by a signal from an arithmetic circuit.