JPH0380692A - Beam index type color image receiving device - Google Patents

Abstract

PURPOSE:To execute the correction of a distortion by applying a signal obtained by multiplying an index signal by a first PLL circuit and a signal obtained by multiplying a horizontal synchronizing signal by a second PLL circuit to a phase comparing circuit and feeding back an output brought to phase comparison to a horizontal deflecting circuit. CONSTITUTION:An index signal of a frequency in the vicinity of n folds of a horizontal synchronizing signal reproduced by an index signal detecting circuit is applied to a first PLL circuit 8, and a signal obtained by multiplying the horizontal synchronizing signal to a frequency in the vicinity of (m/p)Xn folds, and a signal obtained by multiplying the horizontal synchronizing signal to (m/p)Xn folds by a second PLL circuit 31 are applied to a phase comparing circuit 32, and an output signal brought to phase comparison is fed back to a horizontal deflecting circuit. In this regard, (m), (n) and (p) are arbitrary integers. In such a way, correcting signal scarcely having a distortion can be formed without being influenced by the contents of an image to be displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a beam index type color image receiver, which is a color television without a shadow mask.

Conventional technology A cathode ray tube is coated with R, G, B, etc. phosphors in a stripe pattern, and an index phosphor is coated at a position that has some correlation.When an electron beam scans, an index based on the index phosphor is created. Detect signal and P
A color image receiving device in which a switching clock is created in addition to the LLH path, etc., and color signals are switched and displayed in a time-division manner using an analog switch is called a beam index type color image receiving device, and is already in practical use.

Since the beam index type color image receiving device does not have a shadow mask and synchronizes the color signal with the index signal as described above, it is necessary to reduce distortion during deflection. There is also a flat type TV that has the electron gun in a different direction to make it thinner in the depth direction. Conventionally, various methods have been considered to reduce these deflection distortions. One method is to create a correction waveform by mixing parabolic waveforms, sawtooth waveforms, etc., and add it to the deflection circuit for correction.

The conventional beam index type color image receiving device as described above will be explained below with reference to the drawings. FIG. 3 shows the countries in which the conventional beam index type color image receiving apparatus is constructed. In Figure 3, 1 is a video signal input terminal, 2 is a color reproduction circuit that reproduces R, G, and B color signals from the video signal, 3 is an analog switch that switches the color signals in time division, and 4 is suitable for a cathode ray tube. 5 is a synchronous separation circuit that synchronously separates the video signal to create a horizontal sync signal, a vertical sync signal, and a blanking signal; 6 is a timing signal generator that creates a switching timing signal; 7 is an index amplification circuit that amplifies the index signal, 8 is a PLL circuit that manually generates a clock with a frequency that is an integral multiple of the index signal, 9 is a vertical parabolic signal generation circuit, and 10 is a vertical sawtooth wave generation circuit, 11 is a vertical signal synthesis circuit, 1
2 is a vertical output circuit, 13 is a horizontal parabolic signal generation circuit,
14 is a horizontal sawtooth wave generation circuit, 15 is a horizontal signal synthesis circuit, 16 is a vertical/horizontal signal synthesis circuit, 17 is a horizontal output circuit, 18 is a beam index type cathode ray tube, and is a flat cathode ray tube, and I9 is an index phosphor. Light condensing plate that efficiently collects the index light that hits it, 2
0 is a photodiode that converts index light into an electric signal, 21 is a horizontal deflection coil, and 22 is a vertical deflection coil.

The operation of the beam index type color image receiving device having the groove bottom as described above will be explained below. First, the internal structure of the flat cathode ray tube 18 is as shown in FIG.
Three index phosphors (3) are arranged for the two trios of G and B light bodies. Now, when the electron beam is scanned in the horizontal direction, the electron beam hits the index phosphor I shown in FIG. 6, and index light is emitted. The light is collected by a light condensing plate 19, photoelectrically converted by a photodiode 20, and amplified by an index amplification circuit 7. The amplified index signal is applied to the PLL circuit 8 to create a clock with twice the frequency. This clock is generated by the timing generation circuit 6.
Then, reset with a blanking signal and divide the frequency into 1/3 to create a three-phase switching signal. The R, G, and B signals inputted to the analog switch 3 are time-divisionally switched using the switching signal, amplified by the video amplification circuit 4, and applied to the flat cathode ray tube 18 to display a color signal. The flat cathode ray tube 18 has a structure shown in FIG. 4 when viewed from the front. The electron gun is placed almost parallel to the phosphor screen, so if we apply a uniform sawtooth wave and deflect it, we get the image shown in Figure 4 (a).
A fan-shaped deflection distortion occurs as shown in . In order to correct this, the horizontal deflection waveform is modulated with a vertical sawtooth waveform as shown in FIG. For small TVs, it is possible to correct distortion with one or two types of correction waveforms, but as the TV becomes larger, the horizontal parabolic signal generation circuit 13 as shown in FIG.
, the parabolic signal and the sawtooth wave generated by the horizontal sawtooth wave generation circuit 14 are mixed by the horizontal signal synthesis circuit 15 to generate a horizontal correction signal. In addition, the vertical correction waveform is generated by the vertical parabola signal generation circuit 9 and the vertical sawtooth wave generation circuit 1.
0 to create a parabolic signal and a sawtooth wave, respectively, and mix them in the vertical signal synthesis circuit 11.

After modulating the created horizontal correction signal with the vertical correction signal in the vertical and horizontal signal synthesis circuit 16, the horizontal output circuit 17
The electron beam is amplified and added to the horizontal deflection coil 21 to horizontally scan the electron beam. The vertical output circuit 12 amplifies the vertical correction signal and outputs it to the vertical deflection coil 22 for vertical scanning. In FIG. 6, GA indicates glass, BS indicates black stripe, and MB indicates back metal.

Problems to be Solved by the Invention However, with the above-mentioned means, adjustments for creating a correction waveform are complicated and lack practicality.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a beam index type color image receiving device in which a correction waveform can be easily created.

Means for Solving 25B In order to solve the above problems, the beam index type color image receiving device of the present invention provides a first
PLL circuit, and a second PLL circuit that multiplies the horizontal synchronization signal.
, a phase comparison circuit that compares the phases of the outputs of the first and twentieth PLL circuits, and a horizontal deflection circuit that receives the output of the phase comparison circuit as an input. Furthermore, the second invention adds to the above configuration, an A/D converter, a D/A converter, a memory,
The device includes a first switch, a second switch, a white signal generation circuit, and a timing generation circuit.

Effect: With this configuration, a signal obtained by multiplying the index signal by the first PLL circuit and a signal obtained by multiplying the horizontal synchronization signal by the second PLL circuit are added to the phase comparator circuit, and the output of the phase comparison is applied to the horizontal deflection@path. Distortion can be corrected by feedback. Furthermore, the second invention supplies the white signal of the white signal generation circuit to the cathode ray tube by switching the first switch, and converts the output signal of the phase comparator circuit into A/
After converting into D and recording it in the memory, the signal recorded in the memory is read out by switching the second switch and converted to D/A.
It is converted and output to the horizontal deflection circuit.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 shows a block diagram of a beam index type color image receiving apparatus in one embodiment of the present invention. In FIG. 1, I is a video signal input terminal, 2 is a color reproduction circuit, 3 is an analog switch, 4 is a video amplification circuit, 5 is a synchronization separation circuit, 6 is a timing signal generation circuit, 7 is an index amplification circuit, and 8 is a 1 PLL circuit, 9 a parabolic signal generation circuit, 10 a vertical sawtooth wave generation circuit, 11
12 is a vertical waveform synthesis circuit, 12 is a vertical output circuit, 15 is a horizontal waveform synthesis circuit, 16 is a vertical and horizontal waveform synthesis circuit, 17 is a horizontal output circuit, 18 is a flat cathode ray tube, 19 is a light condensing plate, 2
0 is a photodiode, 21 is a horizontal deflection coil, and 22 is a vertical deflection coil, which are the same as the conventional example.

31 is a second PLL circuit that receives the horizontal synchronizing signal as input and generates a signal with a frequency m×n times that signal (mn is an arbitrary integer); 32 is the output of the first PLL circuit 8 and the second PLL circuit 31; 33 is a horizontal deflection waveform generation circuit that creates a basic horizontal deflection waveform;
34 is a counter that counts the output of the first PUL circuit 8.

The operation of the beam index type color image receiving device configured as described above will be explained below. First, the horizontal deflection waveform generation circuit 33 mixes the sawtooth waveform and the parabolic waveform to create a basic horizontal distortion correction signal. When displayed in this state, the flat cathode ray tube 18 displays with distortion in the horizontal direction. The frequency of the index amplifier circuit 7 at this time is determined by the number of index phosphors applied during the effective horizontal scanning period, but in a 6-inch size, the horizontal resolution is approximately 200 lines, and the trio of phosphors is There are approximately 200 pieces. In this embodiment, the number of index phosphors is 3/2 times the number of trios, and several index phosphors are added to achieve start synchronization. The index frequency is determined as described above, but now it is assumed to be a frequency n times the horizontal synchronization frequency. Furthermore, since deflection distortion occurs, the frequency differs depending on each position in the horizontal scanning period.

This signal is added to the first PLL circuit 8 to obtain a signal with twice the frequency. This frequency is divided into 1/2 by a counter 34 and applied to the phase comparator circuit 32. The second PLL circuit 31 multiplies the horizontal synchronizing signal by n times. When this signal is compared in phase with the output signal of the counter 34 as a reference, an error signal is generated. This signal is sent to the horizontal deflection waveform generation circuit 3.
The basic horizontal distortion correction signal generated in step 3 is combined with the horizontal waveform synthesis circuit 15 to create a precise horizontal distortion correction signal.

As described above, according to this embodiment, the signal obtained by multiplying the index signal by the first PLL circuit 8 and the signal obtained by multiplying the horizontal synchronization signal by the second PLL circuit 31 are transmitted to the phase comparison circuit 3.
In addition to 2, by feeding back the phase-compared output to the horizontal deflection circuit, distortion can be corrected, and the labor of complicated adjustment can be reduced.

Other embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a block diagram of a beam index type color image receiving apparatus according to another embodiment of the present invention. In Fig. 2, 1 is a video signal input terminal, 2 is a color reproduction circuit, 3 is an analog switch, 4 is a video amplification circuit,
5 is a synchronization separation circuit, 6 is a timing signal generation circuit, 7 is an index amplifier circuit, 8 is a first PLL circuit, 9 is a vertical parabolic signal generation circuit, 10 is a vertical sawtooth wave generation circuit, 11 is a vertical waveform synthesis circuit, 12 is a vertical output circuit, 1
5 is a horizontal waveform synthesis circuit, I6 is a vertical and horizontal waveform synthesis circuit,
17 is a horizontal output circuit, 18 is a flat cathode ray tube, 19 is a condenser plate, 20 is a photodiode, 21 is a horizontal deflection coil, 2
2 is a vertical deflection coil, which is the same as the conventional example. Further, 31 is a second PLL circuit, 32 is a phase comparison circuit, 33 is a horizontal deflection waveform generation circuit, and 34 is a counter, which are the same as in the previous embodiment.

A white signal generating circuit 41 outputs a white signal as R, G, and B signals. 42 is an A/D converter that converts the output analog signal from the phase comparison circuit 32 into a digital signal; 43
is a memory, 44 is a D/A converter that converts the digital signal read from the memory 43 into an analog signal, and 45 is a tie main that controls the A/D converter 42) memory 43 and the D/A converter 44. 46 is a switch for switching between the signal from the D/A converter 46 and the signal from the phase comparison circuit 32; 47 is a switch for switching between the R, G, and B signals of the color reproduction circuit 2 and the white signal of the white signal generation circuit 41; It is a switch.

The operation of the beam index type color image receiving device configured as described above will be explained below. First, switch the switch 47 to the (a) side and press the flat cathode ray tube 1.
A white signal is supplied to 8. As a result, the index phosphor of the flat cathode ray tube is exposed to a uniform, high-level electron beam over the entire horizontal and vertical scanning area. When this signal is photoelectrically converted by the photodiode 20, it is possible to obtain a high-level index signal with no phase difference due to the signal. The phase comparison circuit 32 compares the phases of the index signals obtained in this manner as in the embodiment described above, and sets the switch 46 to the (a) side to output the index signals to the horizontal waveform synthesis circuit 15 and the A/D converter. 42 and stored in the memory 43. When displaying the video from video signal input terminal 1,
When the switches 46 and 47 are switched to the (b) side, the information stored in the memory 43 is converted into an analog signal by the D/A converter 44 and applied to the horizontal waveform synthesis circuit 15.

As described above, according to this embodiment, the white signal generation circuit 41, the first switch 47, the second switch 46, and the D/
An A converter 44, an A/D converter 42, a memory 43,
It is composed of a tie control generation circuit 45, a first PLL circuit 8, a second PLL circuit 31, a phase comparison circuit 32, and a horizontal deflection circuit. While displaying the generated white signal, a signal obtained by multiplying the index signal by the first PLL circuit 8 and a signal obtained by multiplying the horizontal synchronization signal by the second PLL circuit 31 are applied to the phase comparison circuit 32. Then, by switching the second switch 46, the phase-compared output is fed back to the horizontal deflection circuit, A/D converted, and recorded in the memory 43. Further, the first switch 47 is switched to the other side to display the image, and at the same time, the second switch 46 is switched to the other side to D/A convert the signal recorded in the memory 43 and feed it back to the horizontal deflection circuit. As a result, a correction signal with less distortion can be created without being affected by the content of the video to be displayed.

Effects of the Invention As described above, the present invention includes a white signal generation circuit, a first switch, a second switch, a D/A converter, an A/D converter, a memory, and a timing generation circuit. , the first PL
By providing an L circuit, a second PLL circuit, a phase comparator circuit, and a horizontal deflection circuit, it is possible to automatically generate a correction signal with little distortion, which has great practical effects. .

[Brief explanation of drawings]

- Figure 3 is a block diagram of the conventional example, Figure 4 is a front view of a cathode ray tube including an example of a distorted image, Figure 5 is a conventional correction waveform diagram, and Figure 6 is a flat diagram. FIG. 2 is a cross-sectional view of a cathode ray tube. 8...First PLL circuit, 18...Flat cathode ray tube, 31...Second PLL @ path, 3
2...Phase comparison circuit, 33...Horizontal deflection waveform generation circuit, 41...White signal generation circuit, 4
2... A/D converter, 43... Memory, 44... D/A converter, 45... Timing generation circuit, 46... ...Second switch,
47...First switch.

Claims (2)

[Claims] (1) A cathode ray tube with a light body arranged in a stripe pattern and index phosphors arranged in a stripe pattern in a position correlated with the light body, and a horizontal synchronization signal reproduced by an index signal detection circuit. An index signal with a frequency approximately twice that of the horizontal synchronizing signal is added to the first PLL circuit, and the signal is multiplied to a frequency approximately twice the horizontal synchronizing signal (m/p)×n (m, n, p are arbitrary integers); A signal obtained by multiplying the horizontal synchronization signal by (m/p) x n (m, n, p are arbitrary integers) by a second PLL circuit is added to the phase comparator circuit, and the phase-compared output signal is horizontally deflected. A beam index type color image receiving device characterized by feedback to the circuit. (2) In the beam index type color image receiving device according to claim 1, a white signal generating circuit;
a second switch, a D/A converter, an A/D converter,
By adding memory and switching the first switch, R
A white signal is supplied to the cathode ray tube instead of the GB signal, and the output signal of the phase comparator circuit is converted into an A/D converter.
After D-converting and recording in the memory, the signal recorded in the memory is converted into an analog signal by a D/A converter instead of the output of the phase comparator circuit by switching the second switch, and the signal is converted into a horizontal deflection circuit. A beam index type color image receiving device characterized by outputting.