JPH02228897A - Vertical deflection circuit - Google Patents

Abstract

PURPOSE:To prevent distortion from being generated on a picture by switching the crest value of a vertical deflecting voltage during a vertical fly-back interval in correspondence to the frequency of a vertical synchronizing signal. CONSTITUTION:A pump-up switch SW2 is turned on between terminals (d)-(e) during the fly-back interval according to the detection signal of a detection circuit 6 and a voltage is applied from a terminal (g) of a 60/120Hz switch SW1 to a terminal (j). During a time excepting for the fly-back interval, the switch is turned on and a voltage V1 is applied to the terminal (j) of a vertical output circuit 3. When vertical deflection is 60Hz, the 60/120Hz switch SW1 is turned on between the terminals (g)-(i) and when the deflection is 120Hz, the switch is turned on between the terminals (g)-(h) by manual operation. Thus, when the frequency of the vertical synchronizing signal reproduces the video signal of 120Hz, the vertical fly-back is made early since the deflecting voltage of the vertical fly-back period is higher in comparison with the case of 60Hz. Then, a display period is prolonged and the distortion is not generated on the picture.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vertical deflection circuit used in a stereoscopic television receiver or the like using a time-sharing shutter system.

2. Conventional Principles The principle of conventional stereoscopic television using one type of time-sharing shutter is as shown in FIGS. 9 to 11. This takes advantage of the binocular parallax of the human eye, and images of objects seen from different angles are projected onto the retinas of the left and right eyes 100 and 101, and these are fused into one three-dimensional image. visible as a statue.

First, Figure 9(a) shows two points P existing on a horizontal plane,
Q schematically represents a ladder where images are formed on the y4 membrane. If this is applied to the case of photographing with a three-dimensional camera, the result will be as shown in Fig. 9 (b). In the figure, the left camera 102 corresponds to the left eye 100 and the right camera 103 corresponds to the right eye 101. The image (P'L) captured by the left camera 102 is the right camera 103
When an image is formed to the left of the image (p'R) taken by the left camera 102, and when an image (0''L) taken by the left camera 102 is formed to the image (Q'',) taken by the right camera 103, Divided. This means that if we consider the cathode ray tube surface 104 of the television as shown in FIG. 9(c), Q will appear in front of the television, and P will appear in the back. Therefore, FIG. 10 shows an example of the configuration of a stereoscopic television system using one type of time-sharing shutter. The left camera 102 and the right camera 103 have the same relationship as in FIG.
, frame-by-frame information RI+ R1+ R captured by the right camera 103
3t...I Output R3++. Information from the left camera 102 is sent to a terminal of a switch 105 that switches alternately.
Information from the right camera 103 is input to terminal a. Each information is L I+ L! as shown in the figure. +L3+”'r
L□1+ R1+Rt+ R3+”'+ R*++
and 601 (z) are output at the vertical synchronization signal period. Since the switch 105 switches between terminals b and c and between terminals a and c at the vertical synchronization signal period of 60Hz, Ll+RZ is output from terminal C.
+L;l+R4+... A stereoscopic video signal is output. In other words, the stereoscopic video signal referred to here is 60H
It becomes a video signal in which one set of left and right information of the z vertical synchronization signal period (l frame unit) constitutes one field. Therefore, when the stereoscopic video signal is input to the stereoscopic television 106 shown in FIG. 11, left and right information is displayed for each frame at a cycle of 1/60. Assume that the display screen is viewed with both eyes through the stereoscopic scope 107. The stereoscopic scope 107 consists of a left shutter 108 and a right shutter 109, which open and close in opposite directions with the same vertical synchronization period as the stereoscopic video signal.For example, the stereoscopic video signal shown in FIG. information) is displayed on the stereoscopic television 106 in FIG. 11, the left shutter 108 of the stereoscopic scope 107 is opened;
The right shutter 109 is closed, and the left iI! From ioo, only information from the left camera 102 is seen through the left shutter 108. Next, when the R2 frame signal (information from the right camera) is displayed, the stereoscope 10
7, the left shutter 108 is closed, the right shutter 109 is opened, and the right eye 101 sees only information from the right camera 103 through the right shutter 109. Each operation above 0 is repeated at a vertical synchronization signal period of 60 Hz. Combined with the afterimage effect of the human eye, this becomes equivalent to viewing the binocular parallax video information shown in FIG. 9(C), and a three-dimensional image can be realized.

In other words, the stereoscopic television 106 shown in FIG. 11 can be a Lascous scan television of 60 Hz vertically and 15 KHz horizontally, which is currently commonly used.

However, since conventional 3D television systems using one type of time-sharing shutter normally use a display with a general vertical deflection frequency of 60Hz, the repetition frequency of the left and right images is also 60Hz.
This is done at 0Hz. Therefore, flickering appears in the image, which interferes with the stereoscopic effect. Therefore, in order to solve the occurrence of flicker, the repetition frequency was doubled by 1.
It is conceivable to change the frequency to 20 Hz, but since the vertical retrace time has little dependence on frequency, changing the frequency alone will distort the display screen and make it impossible to obtain a normal image.

The present invention has been made in view of these points, and it is an object of the present invention to provide a novel vertical deflection circuit designed to prevent distortion from occurring on the screen when the vertical deflection frequency is changed.

In order to achieve the above-mentioned object of increasing the frequency of the vertical synchronizing signal, the present invention provides a vertical deflection circuit for a television receiver capable of displaying images with different frequencies of the vertical synchronizing signal. The configuration includes means for switching the peak value of the vertical deflection voltage during the vertical retrace period.

Furthermore, the present invention provides a vertical deflection circuit for a television receiver that can display images with different frequencies of vertical synchronization signals, in which the vertical deflection voltage changes during the vertical retrace period when the frequency of the vertical synchronization signal changes. It is configured to include a circuit that switches the high value in synchronization with vertical synchronization and when no large back electromotive force is generated in the deflection coil.

With this configuration, for example, when reproducing a video signal with a vertical synchronizing signal frequency of 120 Hz, the deflection voltage during the vertical retrace period is higher than when the frequency is 60 Hz, so the vertical retrace occurs quickly ( Therefore, the display period becomes longer and no distortion occurs on the screen.

Moreover, if the switching of the deflection voltage is performed while avoiding a period when a high back electromotive force is generated in the deflection coil, large stress will not be applied to the circuit components.

Back" L± The present invention will be described in detail below based on examples. FIG. 1 is a block diagram of this embodiment. In the figure, l is a vertical oscillation circuit that synchronizes with an input vertical synchronization signal and automatically oscillates, and 2 is a vertical oscillation circuit that generates a sawtooth wave voltage generated in the vertical oscillation circuit 1 and sends it to the final stage vertical output circuit 3. This is an amplification/shaping circuit that amplifies and shapes the waveform to a signal level that can drive 4. The vertical output circuit 3 performs power amplification to allow sufficient current to flow through the deflection coil 4. A pump-up circuit 5 switches and supplies each power source to the vertical output circuit 3. The deflection coil 4 scans the electron beam from top to bottom (vertically) using a sawtooth wave current supplied from the vertical output circuit 3.

FIG. 2 shows the vertical output circuit 3. Pump up circuit 5. An example of a portion consisting of a deflection coil 4 is shown. Here, the vertical output circuit 3 is a transistor power amplifier such as a push-pull amplifier, and the deflection coil 4. Since the power supply voltage Vn from the pump-up circuit 5 is applied to the terminal j of the vertical output circuit 3, which causes the deflection type a I o to flow through the capacitor C1 resistor R, the output waveform voltage Vout at the output terminal k becomes VoutζVn.

The pump-up circuit 5 receives a voltage v1°V from the power supply.
t, Vs as 60/120Hz switch SW, and
The two switches of the pump-up switch 5IIIz switch the voltage and supply it as the power supply voltage to the vertical output circuit 3. Pump up switch Sl'l! are terminals d, e,
f, and is switched by the detection signal SD from the retrace detection circuit 6. The retrace detection circuit 6 is a circuit that extracts only the retrace period from the output voltage waveform of the vertical output circuit 3, and outputs a pulse that is at a high level only during the retrace period as a detection signal SD, as shown in FIG. . During the high level of this detection signal SD, that is, during the retrace period, the pump-up switch SW,
is turned on between terminals d and e, and 60/120 is applied to terminal j.
A voltage from terminal g of the Hz switch SW is applied.

When the detection signal SD is at a low level, that is, at times other than the retrace period, the terminals d and f of the pump-up switch SW2 are turned on, and the voltage v1 is applied to the terminal j of the vertical output circuit 3. This is because when the power supply voltage is increased, the power consumption of the vertical output circuit 3 increases and problems such as heat generation occur.
, V are added only during the vertical retrace period, and the display period is switched to the minimum power supply voltage v1 in order to reduce overall power consumption.

Incidentally, the relationship between the power supply voltages is V s > V z > V +.

The 60/1208Z switch needle consists of terminals H, h, and i, the terminal is connected to the power supply Vt (for 120Hz), and the terminal i is connected to the power supply V□ (for 60Hz). When the vertical deflection is 60Hz, connect between terminals g-4, and when the vertical deflection is 120Hz, connect between terminals g-4.
Turn on the h interval manually. So the vertical deflection is 60+
At the time of lz, the power supply voltage v2 is led to the terminals i-ge and is applied as the power supply voltage to the vertical output circuit 3 during the vertical retrace period. Next, in the case of vertical 120 Hz deflection, the power supply V is led to the terminals hge and is also applied as the power supply voltage of the vertical output circuit 3 during the vertical retrace period.

These deflection waveforms and each switch SW+, 5lll! FIGS. 3 to 6 show the state.

Incidentally, FIG. 3 shows the deflection waveform in the case of 60 Hz deflection, and FIG. 4 shows the states of each switch SW, SW2 in that case. On the other hand, Fig. 5 shows the deflection waveform in the case of 120Hz deflection, and Fig. 6 shows the switch SW in that case.
,, SW! It shows the status of.

60) At the time of 1z deflection, 1. +1. is the display period + t
3 is the vertical retrace period, and the voltage applied between t and u is V
l+display period 1. +1. The bitter voltage is V. On the other hand, 1201 (at the time of 2 deflections, the voltage applied to the vertical blanking period t, l is V1 + the voltage applied to the display period t% + t,' is V. Here, each waveform (a
) The period of each waveform at the time of 120Hz deflection must be approximately half of the period of 120Hz deflection. Although it can be achieved, the vertical retrace is a deflection current■. It is created by generating a back electromotive force in the deflection coil 4 due to a sudden change in the sawtooth wave.
In order to shorten the retrace period, increase the power supply voltage (
The back electromotive force energy must be released. Therefore, 60) Voltage V during retrace period t3 of 1z! For,
During the retrace period t,l of 120 Hz, a voltage V higher than v2 is applied. This doubles the vertical deflection by 12
Even at 0 Hz, a necessary and sufficient display period can be ensured. Therefore, it is possible to realize a vertical deflection circuit that does not cause distortion on the screen when the vertical deflection is either 60 Hz or 12082 Hz.

By the way, as mentioned above, when applying a high power supply voltage only during the vertical retrace period to increase the peak value of the vertical deflection voltage, when a high back electromotive force is generated in the deflection coil, the 60/120H
There is a possibility that the power supply voltage may be changed by operating the z switch SW, which causes a large electrical stress to be applied to each circuit component.

Therefore, in the embodiment shown in FIG. 7, the power supply voltage applied during the vertical retrace period is switched when no large back electromotive force is generated in the deflection coil. In the same figure, a pump-up circuit 5 has a latch circuit 7 and a 60/120 Hz instruction switch 8 in addition to the structure of the embodiment shown in FIG. The output of the retrace detection circuit 6 is applied to the clock terminal CM of the latch circuit 7, and the output of the retrace detection circuit 6 is applied to the data terminal CM.
The output of the 120Hz indicating switch 8 is provided. The relationship between these inputs and the Q output is shown in FIG. According to this configuration, no matter what timing the 60/120 Hz instruction switch 8 is switched, the start of the vertical retrace period (
Therefore, the 60/12011z switch is switched when no high back electromotive force is generated in the deflection coil.

Therefore, no large electrical stress is applied to the circuit components.

As described above, according to the present invention, vertical deflection can be properly performed at both frequencies, for example, 60 Hz and 1201 (z) with an extremely simple circuit configuration, and only during the vertical retrace period can the beam be deflected according to the frequency. Since the peak value of the vertical deflection voltage is changed by changing the peak value of the vertical deflection voltage, it is possible to realize a vertical deflection circuit that reduces power consumption and does not cause flicker or screen distortion.

Furthermore, according to the present invention, the peak value of the vertical deflection voltage during the vertical retrace period is switched when a high back electromotive force is not generated in the deflection coil, so that no large electrical stress is applied to the circuit components. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the vertical deflection circuit of the present invention, FIG. 2 is a diagram showing one embodiment of the main parts thereof, and FIGS. 3, 4, 5, and 6 are explanatory diagrams thereof. It is. FIG. 7 is a diagram showing another embodiment of the main part in FIG.
The figure is an explanatory diagram thereof. FIG. 9, FIG. 10, and FIG. 11 are diagrams for explaining a time-division shutter type three-dimensional television. 3.--vertical output circuit, 4--deflection coil. 5-pump up circuit 16--vertical retrace detection circuit 7-latch circuit, 8...60/120Hz indication switch SW
+---60/120Hz switch. SW, --Pump up switch. VI+ Vt, V3'-- one power supply voltage. Figure 7

Claims (2)

[Claims] (1) In a vertical deflection circuit for a television receiver capable of displaying images with different vertical synchronization signal frequencies, means for switching the peak value of the vertical deflection voltage during the vertical blanking period according to the frequency of the vertical synchronization signal. A vertical deflection circuit characterized by comprising: (2) In a vertical deflection circuit for a television receiver that can display images with different vertical synchronization signal frequencies, when the frequency of the vertical synchronization signal changes, the peak value of the vertical deflection voltage during the vertical retrace period A vertical deflection circuit characterized by having a circuit that switches in synchronization and when a large back electromotive force is not generated in a deflection coil.