JPH0628459B2 - 3-tube type projector - Google Patents

Description

The present invention relates to a three-tube projector in which projection type cathode ray tubes for red, green and blue images are arranged inline.

[Outline of Invention]

According to the present invention, the three tubes are arranged in-line to correct at least vertical trapezoidal distortion of the image by the right and left cathode ray tubes, and the image by the cathode ray tube is corrected by the correction magnets arranged corresponding to the four corners of the raster of the cathode ray tube. The vertical and horizontal pink distortion distortion is corrected, and the raster distortion due to the correction magnet is corrected by supplying a correction signal that cancels the raster distortion due to the correction magnet to the vertical sub-deflection coil. .

[Conventional technology]

FIG. 5 shows a three-tube projector in which three tubes are arranged in line. In the figure, (1R), (1G) and (1
B) is a projection type cathode ray tube for red, green and blue images, respectively, and image lights l _R , l _G and l _{B from each} are projected lens (2
The projected image is superimposed on the screen (3) via R), (2G) and (2B), and a color image is displayed on the screen (3).

In this case, the green optical axis is perpendicular to the screen (3), while the red and blue optical axes are laterally offset by θ.
Therefore, when nothing is done, the screen
(3) Red, green and blue images S _R , S _G and S _{B above}
Are as shown in FIGS. 6A, 6B and 6C, respectively, and vertical trapezoidal distortion and horizontal linearity distortion occur in the red image S _R and the blue image S _B.

Therefore, conventionally, for example, a sub-deflection coil is provided, and an appropriate correction signal is supplied to the sub-deflection coil to perform the correction. For example, in order to correct vertical trapezoidal distortion, a signal obtained by modulating a horizontal-cycle sawtooth wave signal with a vertical-cycle sawtooth wave signal is supplied to the vertical sub-deflection coil as a correction signal. Further, in order to correct the horizontal linear distortion, a parabolic wave signal with a horizontal period is supplied to the horizontal sub-deflection coil as a correction signal.

When corrected in this way, the cathode ray tube (1R) and
In the raster of (1B), raster distortion in the direction opposite to the above-mentioned image distortion will be formed.

By the way, conventionally, it is known that correction magnets are arranged corresponding to the four corners of the raster of the cathode ray tube, and thereby vertical and horizontal pink distortion distortion is corrected.

For example, in FIG. 7, (11) is an insulating frame that constitutes the main deflection yoke, and its peripheral cylinder corresponds to the four corners of the raster.
The correction magnet (14) is fixedly held on the (12) using the metal fitting (13), and by adjusting the rotational position of the magnet (14), vertical and horizontal pink distortion distortion is shown as shown by the broken line in FIG. The rasters with the are corrected as shown by the solid line in the figure.

[Problems to be solved by the invention]

In this way, the vertical and horizontal pink distortion can be corrected using the correction magnet (14), but as described above, the cathode ray tube (1
R) and (1B) rasters are distorted to correct the image distortion on the screen (3). To apply the pink distortion distortion correction by the correction magnet to the cathode ray tube of the projector, Such inconvenience occurs. That is, the cathode ray tube (1
R), (raster L _R of _1B), a peripheral portion of the L _B correction magnets (14)
Since the distances to the rasters L _R and L _B are different depending on the positions of the rasters L _R and L _B (see a to d of FIG. 9A), waviness distortion occurs in the rasters L _R and L _B due to uneven correction. . 9th
FIGS. A and B show the cathode ray tubes (1R) and (1G) rasters L _R ,
Although it shows L _B , it has undulation distortion as shown by the solid line in the figure. The broken line in the figure shows a preferable ideal raster.

In view of this, the present invention corrects the raster distortion due to the correction magnet in the projector as described above.

[Means for solving problems]

The present invention relates to a projection type cathode ray tube for red, green and blue images (1R), (1G) and (1B) arranged in an in-line arrangement, and a projection type for red, green and blue images. Left and right projection type cathode ray tubes of cathode ray tubes (1R), (1G), (1B)
The vertical and horizontal pink distortion correction magnets (14) are provided corresponding to the four corners of the rasters (1R) and (1B) respectively, and are provided in the left and right projection cathode ray tubes (1R) and (1B), respectively. And a vertical sub-deflection coil (24), the first signal in which the horizontal cycle sawtooth wave signal is modulated by the vertical cycle sawtooth wave signal, and the horizontal cycle parabolic wave signal is modulated by the vertical cycle sawtooth wave signal. A correction signal that generates a positive-phase and negative-phase correction signal that is a composite signal of the generated second signal and that is supplied to the vertical sub-deflection coils (24) of the left and right projection cathode ray tubes (1R) and (1B), respectively. With the signal generating means, the left and right projection type cathode ray tubes (1R), by the vertical sub-deflection coil (24) of (1B) and the correction signal generating means, by the left and right projection type cathode ray tubes (1R), (1B) Vertical trapezoidal distortion of the image on the screen and left and right projection cathode ray tubes (1R) and (1B) raster 4
It is a three-tube type projector in which the vertical and horizontal pink distortion correction magnets (14) provided corresponding to the corners are used to correct the raster distortion.

[Action]

Raster L _R of a cathode ray tube (1R) and (1B) by the correction signal supplied to the vertical auxiliary deflection coil _(24), the L _B, correction magnets
Raster distortion in the opposite direction to the raster distortion due to (14) is formed. Therefore, this raster distortion and the raster distortion due to the correction magnet (14) are canceled and the raster distortion is corrected.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a correction circuit for a cathode ray tube (1R) that produces raster distortion, that is, undulation distortion, as shown by the solid line in FIG. 9A.

In the figure, (21) is a correction signal generation circuit, and from this generation circuit (21), the signal S _ps of the horizontal period (1H) shown in FIG. _3D is a sawtooth wave signal of the vertical period (1V). The signal S _d (illustrated in FIG. 4D) modulated by is extracted. The swell portion l _O of the signal of the horizontal cycle shown in FIG. 3D is adjusted in phase so as to correspond to the swell of the raster L _R as shown by the solid line in FIG. 9A.

The generation circuit (21) is configured as shown in FIG. 2, for example. In the figure, the terminal (21a) is supplied with a signal S _a (shown in FIG. 4A) obtained by modulating the parabolic wave signal S _p of horizontal cycle shown in FIG. 3A with a sawtooth wave signal of vertical cycle. To be done. Further, the terminal (21b) is supplied with a signal S _c (shown in FIG. 4C) obtained by modulating the sawtooth wave signal S _s having the horizontal cycle shown in FIG. 3C with the sawtooth wave signal having the vertical cycle. It These signals S _a and S _c have the minimum amplitude at the center of vertical scanning, and their polarities are inverted in the first half and the second half of vertical scanning.

Signal S _a is supplied to the terminal (21a) is integrated by operational amplifier (21c), is replaced secretly further phase, the connection point P 3
A signal S _{b having} a horizontal period signal S _P ′ having a rounded waveform of a parabolic wave shown in FIG.
(Illustrated in FIG. 4B) is obtained. Then, this signal S _P ′ and the signal S _c supplied to the above-mentioned terminal (21b) are combined, and the correction signal S _d (shown in FIG. 4D) is taken out to the terminal (21d).

Returning to FIG. 1, the correction signal S generated by the generation circuit (21)
_d is supplied to the correction signal synthesizing circuit (22) and is synthesized with another correction signal. In this case, the vertical sub-deflection coil (24) described later
The levels of the correction signals S _{d and the} like are adjusted and combined in accordance with the correction amount required in step 1.

The combined signal _SAL from this combining circuit (22) is output to the output circuit (23).
Is supplied to the vertical sub-deflection coil (24) arranged in the neck portion of the cathode ray tube (1R) from this output circuit (23), and the combined signal S
A current corresponding to _AL is applied. In addition, in FIG. 1, (2
5) is a resistor for obtaining the feedback signal.

In the above configuration, the vertical auxiliary deflection coil (24), a current flows due to the correction signal S _d which is generated by the generator (21). Raster L _R of a cathode ray tube (1R) by the current, the waviness distortion by the above-described correction magnet (14) opposite the direction of the swell strain is formed (see a chain line in FIG. 9 A). Therefore, the raster distortion due to the correction magnet (14) is offset and corrected.

The example of FIG. 1 shows a correction circuit for a cathode ray tube (1R) that produces raster distortion as shown by the solid line in FIG. 9A.
Cathode ray tube producing raster distortion as shown by the solid line in FIG. 9B
The correction circuit of (1R) is similarly configured. However, the positive and negative of the correction signal S _d (shown in FIG. 4D) are inverted and used.

〔The invention's effect〕

According to the present invention described above, since the correction signal for canceling the raster distortion due to the correcting magnet is supplied to the vertical sub-deflection coil, it is possible to correct the raster distortion by the correcting magnet for correcting the pink distortion. You can get a good image on top.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of an embodiment of the present invention, FIGS. 2 to 4 are diagrams for explaining the same, FIG. 5 is a configuration diagram of a three-tube type projector, and FIG. FIG. 7 is a diagram for explanation, FIG. 7 is a diagram showing a magnet for correcting pink distortion, and FIGS.
The figure is a figure for the explanation. (1R) to (1B) are projection type cathode ray tubes, (3) is a screen,
(14) is a correction magnet for pink distortion, (21) is a correction signal generating circuit, and (24) is a vertical sub-deflection coil.

Claims (1)

[Claims] 1. A three-tube projector having a projection type cathode ray tube for red, green and blue images arranged in-line, wherein a left and right projection type of the projection type cathode ray tubes for red, green and blue images is used. Vertical and horizontal pink distortion correction magnets respectively provided corresponding to the four corners of the raster of the cathode ray tube, vertical sub-deflection coils respectively provided at the left and right projection type cathode ray tubes, and a sawtooth wave signal with a horizontal period. Is a composite signal of a first signal modulated with a vertical period sawtooth wave signal and a horizontal period parabolic wave signal with a second signal modulated with a vertical period sawtooth wave signal. Correction signal generating means for generating a correction signal and supplying it to the vertical sub-deflection coils respectively provided on the left and right projection type cathode ray tubes, and the vertical sub electrodes respectively provided on the left and right projection type cathode ray tubes. Deflection coil and And the correction signal generating means, respectively, provide vertical and horizontal pink twitches corresponding to the vertical trapezoidal distortion of the image on the screen by the left and right projection type cathode ray tubes and the four corners of the raster of the left and right projection type cathode ray tubes. A three-tube type projector characterized in that raster distortion by a distortion correction magnet is corrected.