JPS5820067A - Compensating circuit for deflecting distortion of color camera - Google Patents

Abstract

PURPOSE:To reduce the deflecting distortion and to increase the accuracy of registration, by superposing a proper compensating signal current on a DC current which is flowed to a rotation coil and performing the rotation control so that it functions also asymmetrically. CONSTITUTION:A proper compensating signal is produced from a compensating signal producing circuit 5 and then superposed on a certain DC bias. Then a rotation coil 4 is driven by a current source through a current buffer circuit 6. If a vertical deflected sawtooth wave (a), for example, is used as a compensating signal, an asymmetrical rotation is possible as shown by the figure (b). As a result, the asymmetrical distortion component can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color camera deflection distortion correction circuit for correcting deflection distortion of an image pickup tube of a color television camera (hereinafter abbreviated as camera).

In general, a three-tube camera uses three image pickup tubes to obtain the three primary colors of light (red, green, and white), and each image pickup tube's optical position and electrical deflection characteristics Adjust the
It must be in a condition that does not cause color shift.

゛ This *m is generally called registration storage adjustment, but it includes electrical registration storage adjustment, size adjustment to change the size of the imaged screen, centering adjustment to change the center position, and surface adhesion nearness. During the linearity adjustment, a method such as rotating the entire screen was commonly used.

Among these, 4-Chi S/1isyl! 1 is implemented by an image pickup tube deflection-il assembly shown in FIG. 111. Figure 1 is a cross-sectional view of the image pickup tube deflection coil.
Apply a direct magnetic field to the target part of the image pickup tubes 1 to J, rotate the scanning section (raster) of the electron beam, and ), G (bound), and B (back) channels.

According to this method, images are taken as shown in FIG.
Ii can be rotated point-symmetrically with the center of m as a focal point.

Conventionally, electrical registration was adjusted by adjusting the size, centering, linearity, low chiron, etc. mentioned above, but these adjustment functions alone were not enough to avoid the asymmetrical effects that appear on a round screen when captured with an actual camera. The distortion components cannot be removed.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional technology, and it superimposes an appropriate correction signal current on the DC current flowing through the rotation coil, so that the rotation adjustment functions asymmetrically, thereby reducing deflection distortion. It is an object of the present invention to provide a force 2-camera deflection distortion correction circuit that can improve registration accuracy.

Embodiments of the second camera deflection distortion correction path according to the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing the configuration of one embodiment.

In FIG. 2, reference numeral 5 denotes a correction signal generation circuit, which generates an appropriate correction signal, superimposes it on a certain DC' bias, and causes a current buffer circuit 6 to drive the giro-tension coil 4 with a current source. .

For example, when the correction signal is only DC bias, the scanning section of the image pickup tube only rotates clockwise or counterclockwise around the center of the screen, as shown in Figure 3. If a vertically polarized sawtooth wave as shown in Figure 4 (Hatake) is used as a signal, the signal will be asymmetrical (B) as shown in Figure 4, (A).
Turn around.

In addition, in Fig. 5, the sawtooth wave exists only for a period of -vertical deflection period (1v and mark 9 in Fig. 4).
If such a correction signal is used, only the lower part can be rotated as shown in FIG. 5, 6).

Similarly, if a horizontal deflection sawtooth wave as shown in Fig. 6(,) is used as a correction signal, it will rotate asymmetrically as shown in Fig. 6(a), and -horizontal deflection period (IH in Fig. 6). Figure 7 (
If a correction signal such as Jl) is used, only the right part can be rotated as shown in No. 7&I)O.

In addition, in the example of the correction signal shown in Fig. 4 to Fig. 7 0), the explanation will be made using a positive polarity signal, so the corresponding scanning sections are as shown in Fig. 4 to Fig. 7 0).
It rotates clockwise as shown in FIG. 7 (0), but if the polarity of the correction signal is reversed and a negative polarity is used, it will rotate counterclockwise.

For the sawtooth wave used as a correction signal, Figs. 8 to 11,
(If correction signals with different phases are used, as shown in FIG. The direction of rotation is reversed, which is similar to expansion.

Furthermore, if the waveforms shown in FIGS. 12(a) to 19(,), in which the waveforms in which sawtooth waves exist by 5/H are modulated by vertically polarized sawtooth waves, are used as correction signals, the corresponding waveforms can be corrected. One of the four scanning sections rotates and changes as shown in FIGS. 12(a) to 6), respectively.

Furthermore, it goes without saying that asymmetrical deflection distortion can be corrected by using other correction signals such as a rectangular wave or a parabob wave in addition to the sawtooth wave.

By appropriately combining the nine corrections described above and further adjusting them together with conventional adjustment items, general asymmetrical registration storage deviations can be dealt with.

For example, in Fig. 20, if there is trapezoidal distortion on one side of the scanning section, as shown in (&), the correction signal in Fig. 6 (a) will be applied, and the same rotation as shown in (.) will be applied. Para (BOW) correction (f) is performed to curve the scanning section into an arcuate shape, and V skew (IKICW) is applied to remove the tilt in the V direction.
Correction -) is performed to reduce deflection distortion.

As described above, according to the second feature of the present invention - the camera deflection distortion correction circuit, an appropriate correction signal current is superimposed on the DC current flowing through the rotation coil, so rotation adjustment that may cause damage to the camera is made asymmetrical. 4 deflection distortion can be corrected, and registration accuracy can be improved.

[Brief explanation of the drawing]

Figure 1 is a cutaway view of the image pickup tube deflection correction circuit of a conventional camera, Figure 2 is a block diagram showing an embodiment of the color camera deflection distortion correction circuit of the present invention, and Figure 3 is a conventional camera tube deflection correction circuit. Figures 4(a) to 19(1) showing the changes in the scanning section due to the rotation image function of The diagrams shown in Fig. 4 (a) to Fig. 19 (b) are diagrams showing the changes in the scanning area -〇 corresponding to the correction signals of Fig. 4 (a) to Fig. 19 (b), respectively. Fig. 20 (Hata) to FIG. 20(g) are diagrams showing an example of removing asymmetric deflection distortion by the color camera deflection distortion correction circuit of the present invention. 1... Imaging tube, 5... Correction signal generation circuit, 6...
Current rotation times p, 4...Rotation coil. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 3 (a) (b) Figure 7 (a) (b) (a) Figure 8 (b) Figure 9 Figure 11 Figure 13 ( a) (b) Figure 15 (a) (b) (a) Figure 16 (b) Figure t417 (a) (b) (a) Figure 20

Claims (1)

[Claims] It is made from a rotary coil that applies a direct magnetic field to the target part of the image pickup tube in a color television camera to rotate the scanning section of the electron beam, and a direct deflection drive pulse or a horizontal deflection drive pulse. A color camera deflection distortion correction circuit such as a circuit that generates a correction signal current having a predetermined waveform Kll shape using pulses and superimposes it on the DC current flowing through the rotary lens.