JPS631793B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to precisely perform color convergence on the projection surface of a projection type color television, and in particular to prevent deviations in color convergence at the four corners of the projection surface due to changes in ambient temperature or changes over time. This is to detect and correct this deviation.

Misconvergence of the three colors R, G, and B (red, green, and blue) on the projection surface (screen) of a projection television is adjusted by correcting the shape of the deflection current of the television receiver on the light source side. It's summery. That is, this is done by adjusting so that the three colors overlap to form white. In this case, the dot pattern or crosshatch pattern on the projection surface is adjusted visually, but even once the convergence of these three colors is adjusted, the television receiver as the three light sources is Changes in position, characteristics of the polarizing circuit, position of the screen surface, etc., ambient temperature, and other aging and environmental conditions can cause misconvergence, resulting in loss of convergence. Therefore, the convergence adjustment must be made again. This drawback becomes a serious problem in high-definition projection television receivers having a large number of scanning lines. In particular, misconvergence in 4-even requires frequent adjustment.

The present invention eliminates the conventional drawbacks by providing a photoelectric conversion element or an optical fiber that guides light to the photoelectric conversion element on the screen surface, detecting the light receiving positions of three colors, and correcting misconvergence.

An embodiment of the present invention will be described below based on the drawings. FIG. 1 is an explanatory diagram of the operation in this embodiment, FIG. 2 is a configuration diagram of the photodetector on the screen surface in FIG. 1, and FIG. 3 is a configuration diagram explaining correction of the deflection current waveform in FIG. 1. , FIG. 4 is a waveform diagram of the deflection current to be corrected. In Figure 1, a,
b and c show the R, G, and B signals for the horizontal scanning period at the start of the vertical scanning period, respectively. A standard fixed signal such as 102, 202, 302 is forcibly inserted for a certain short period, and also at the end of the scan. If normal signals 1, 2, and 3 already exist at the position where this fixed signal is to be inserted, the signals in that portion are interrupted and then the predetermined fixed signal is inserted. e indicates the position of the projected images 6, 601, 602 relative to the fixed signals on the screen surface 5; when the fixed signals 101, 201, 301 are gathered at point 6, it becomes a white bright spot. When any color comes to the position of point 601, the current 4 in the deflection current waveform (FIG. 1d) is corrected to a large current 401 at the beginning of the scanning period for that color. It can be moved to 6. By applying the same principle to the end of the scanning period, the brightness of the three colors can be matched to white. In this way, horizontal light convergence is possible at the upper left and right corners of the screen surface 5, and standard signals 101 to 301, 102 to 302, such as a, b, and c, are applied to the horizontal direction at the lower left and right corners, respectively. By inserting 302 at the end of the vertical scanning period, convergence correction in the horizontal direction can be realized using the same means as described above. Although the convergence at the four corners in the horizontal direction has been described above, it is natural that the convergence at the four corners in the vertical direction can also be corrected using the same principle.

Next, the structure of the photodetector on the screen surface 5 will be explained with reference to FIG. Three optical fibers 8R ₁ in the horizontal direction for R among the colors R, G, and B;
The end faces 7R ₁ , 7R ₂ and 7R 3 _of 8R ₂ and 8R ₃ are arranged. Similarly, two optical fiber end faces 7R ₄ and 7R ₅ are additionally arranged in the vertical direction, and 7G and 7B are arranged in the horizontal and vertical directions for other colors as well. With the above, each color can be detected at the upper left corner of the screen surface 5, and the same configuration is performed for the other three corners.

Figures 3 and 4 show an example of the convergence correction circuit configuration and correction method for the horizontal R color in the upper left corner.
This will be explained with a diagram. The light guided by the three optical fibers 8R ₁ to 8R ₃ is transmitted through photodiodes 9R ₁ to 9R ₃ and amplifiers 10R 1 to 9R ₃ as light intensity conversion elements, respectively.
10R ₃ , the signal level synthesizer 11R detects the positional deviation amount of the red pattern on the screen 5, and gives the output signal to the correction signal circuit 16R;
This output 12R corrects the output current of the horizontal deflection circuit 13R, and causes the deflection current to flow through the deflection yoke 14R and the DC blocking capacitor 15R.

In Fig. 2, when the R light is applied to the normal position on the screen, it is received by the light receiving section _7R2 , the light is guided by the optical fiber _8R2 , and the relative amplitude is set to positive polarity by the photodiode _9R2 . Unit 2
An electrical pulse signal is obtained. Along with this output, a negative pulse signal 101R with a relative amplitude of unit 2 obtained separately from the standard signal side is input to the signal level synthesizer 11R, and its output becomes O potential. In other words, no correction is required. However, R
When the light deviates from its normal position on the screen and is received by the light receiving section _7R1 , a pulse signal with a positive polarity and a relative amplitude of 3 is obtained at the output of the amplifier _10R1 , and a negative polarity is generated at the signal level synthesizer 11R. signal level synthesizer 1.
The output of 1R becomes positive, and the deflection current 4R in FIG. 4 is corrected so that the starting end of scanning is 401R. Conversely, when light is received by the light receiving section _7R3 , a pulse signal of positive polarity and relative amplitude of unit 1 is obtained at the output of the amplifier _10R3 , which is input to the signal level synthesizer 11R together with the negative polarity pulse signal 101R. , the output of the signal level synthesizer 11R becomes a negative level, and the starting end of the deflection current 4R is corrected as 402R.

Also, depending on the amount of deviation of the light projection position from the normal position, two light receiving sections 9R ₂ and 9R ₁ or 9R ₂ and 9R ₃
Since the amount of received light is determined according to the ratio of that position, detailed correction is possible. The combined output of the signal level synthesizer 11R is pulse 1 synchronized with the standard signal.
It is obtained only after 01R, and the level is maintained until the next synchronization pulse is input.

Note that when performing position detection for the three colors R, G, and B, if the light receiving section is configured as shown in FIG. 2, light other than the target color will also be received. FIG. 5 shows an embodiment of this standard signal color identification method. That is, here, the optical fibers 8R ₂ , 8G ₂ , 8B ₂ are guided from the normal positions of the R, G, and B light receiving sections.
As shown in FIG.
R ₂ , 17G ₂ , 17B ₂ are provided, and after separating only the signals of each color with this filter, the photodiode 9
Add to R ₂ , 9G ₂ , 9B ₂ . The colors of optical fibers introduced from other locations can also be separated by the same method as shown in FIG. Another method of standard signal color identification is to vary the insertion timing of the standard signal for each color by an interval twice the vertical synchronization (the raster position is the same at this time interval) or an integer multiple thereof. This can be realized by sequentially inserting the signals and operating the output section or the scanning section of the photoelectric conversion element in synchronization with the standard signal insertion timing.

Furthermore, as a means for detecting the position of the three colors R, G, and B, Fig. 2 shows an example using one optical fiber for each color, but Fig. 6 shows an example using one optical fiber for each color. An example is shown in which an optical fiber (or one bundle of fibers consisting of a plurality of fibers) is used. The optical fiber 802 guides optical signals of three colors, and the wavelength demultiplexer 18 separates the signals into three colors of light, which are then sent to the respective photodiodes 9R ₂ and 9.
Signals are given to G ₂ and 9B ₂ . Wavelength demultiplexer 18
is composed of, for example, a prism. Although FIG. 6 shows the portion of the optical fiber led from the normal position on the projection surface, the optical fiber portion led from other positions can also be separated by the same method. This wavelength demultiplexer 18 is used when inserting the standard signal into the projection light source of three colors sequentially in time by changing the insertion timing of the standard signal for each color by an integer multiple of vertical synchronization x 2, or when inserting the standard signal of each color in time order. It can also be applied when inserting at the same time. FIG. 7 shows another embodiment in which one optical fiber common to three colors is used. The optical signal from the optical fiber 802 is sent to the photodiodes 9R ₂ , 9G ₂ , and 9B ₂ for each color by the optical switch 19 .
It is given via R ₂ , 8G ₂ , and 8B ₂ . In this case, the optical switch 19 is operated by a drive device 191 so as to be movable in the vertical direction (Y direction). That is, a standard signal is inserted temporally sequentially for each color, and the optical switch 19 is operated in synchronization with this signal. An example of the optical switch 19 is shown in which a through hole is provided in the center and both front surfaces are inclined to serve as reflecting mirrors. In the position shown in FIG. 7, light guided by optical fiber 802 is applied to photodiode 9G ₂ via optical fiber 8G ₂ . When the optical switch 19 moves downward and its inclined surface comes to the end face position of the optical fiber 802, the light from the optical fiber 802 is reflected by the inclined surface of the optical switch and is transmitted to the photodiode _9R2 via the optical fiber _8R2 . be guided. light switch 1
If 9 moves upward, photodiode 9B ₂
An optical signal is guided to the Note that when the wavelength demultiplexer is used in place of the optical switch 19, it is not necessary to drive this wavelength demultiplexer in synchronization with the standard signal that is sequentially inserted in time for each color.

FIG. 8 shows another embodiment of standard signal color identification. The optical signals of three colors R, G, and B are guided through one optical fiber 802, and at the same time, the optical signals of R, G,
In contrast to B, one photoelectric conversion element is used. Optical fiber 8 from the normal position of the projection plane
The optical signal of 02 is given to the photodiode 902, and the electrically converted output is input to the signal level synthesizer 11 via the amplifier 1002, and the third
Similarly to the case shown in the figure, a signal received via an optical fiber from a position different from the normal position on the projection plane is also input to the signal level synthesizer 11 via amplifiers 1001 and 1003. Also, a pulse signal 1012 synchronized with the standard signal for each color is also sent to the signal level synthesizer 1.
1 is input. The output of this signal level synthesizer 11 is a signal 2012 synchronized with the sequential insertion of standard signals.
is input to the signal switching section 20 which is switched by
The output of this signal switching section 20 is the correction signal circuit 16
It is given to the corresponding circuit among R, 16G, and 16B.

In the present invention, only one standard signal may be used for each color when color concentration correction convergence is performed, but the amount of light emitted by the phosphor of the cathode ray tube of the television receiver as the light source is sufficient. The same standard signal may be applied to the same phosphor section several times in order to obtain a uniform value.

Further, color concentration correction can be performed automatically at certain intervals (for example, at intervals of several hours), and can also be performed manually at any time. Furthermore, in order to perform color concentration correction at the four corners of the screen, a standard signal may be inserted at an overscan position only during correction. It is also possible to perform color concentration correction not only at the four corners but also at any other position on the screen.

Furthermore, a light-receiving element (photodiode, phototransistor, solar cell, etc.) may be provided directly on the light detection section on the screen surface, or the light may be guided to the light-receiving element via an optical fiber as shown in Figure 2. However, if optical fibers are used, all or part of the fibers can be combined into one (or one
They may be coupled to the fibers of a bundle) using a wavelength demultiplexer or optical switch.

As described above, the present invention has the following advantages.

(1) Color convergence (color concentration) on the projection surface
Since correction can be performed accurately based on the amount of received light, image quality is improved.

(2) Since color convergence can automatically perform a closed-loop function, there is no need to manually adjust the misconvergence caused by factors such as vibration, movement, temperature changes, and changes over time, improving image quality. . Particularly in the case of dosing type televisions with a large number of scanning lines (for example, 1125 high quality type), complicated manual and visual adjustments are not required, and practical performance is guaranteed.

(3) There is no need to stop the reception signal and use a test pattern to adjust the color convergence, and the correction is automatically made in the constant reception state, making it more practical as a receiver.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the operation of the present invention, FIG. 2 is a configuration diagram of a photodetector on the projection surface, and FIG. 3 is a configuration diagram illustrating a method for correcting a deflection current waveform according to an embodiment of the present invention. FIG. 4 is a deflection current waveform diagram, and FIGS. 5 to 8 are configuration diagrams each showing an embodiment of the standard signal color discrimination method. 101, 201, 301, 102, 202, 2
03...R, G, B standard signals, 7R ₁ to 7R ₃ ...
... Optical fiber end face, 8R ₁ ~ 8R ₃ ... Optical fiber,
9R ₁ to 9R ₃ ... Photodiode (photoelectric conversion element), 11R ... Signal level synthesizer, 17R ₂ to 1
7B ₂ ... wavelength selection filter, 18 ... wavelength demultiplexer, 19 ... optical switch, 20 ... signal switching section.

Claims (1)

[Scope of Claims] 1. A photoelectric conversion device is provided on a part of the projection surface of a projection television receiver, and has a light-receiving section that is sensitive to each of the three projection lights of red, blue, and green. The respective information signals of each projection light source are blocked only at a portion corresponding to the position where the section is provided, and a standard signal is inserted for each color into the blocked portion of the signal, and the output signal for each color from the photoelectric conversion device is used. 1. A scanning current control device for a projection television light source, characterized in that the scanning current of each projection light source is controlled. 2. A photoelectric conversion device having a light receiving section corresponding to three projection light sources is constructed from a photoelectric conversion element for each projection light source and an optical fiber connecting the element and the projection surface, and is configured to convert standard signals for the three color projection light sources. The insertion timing is made different for each color by an integer multiple of vertical period x 2, and the signals are inserted sequentially in time, and the output section of the photoelectric conversion element or the scanning current control section is operated in synchronization with the standard signal insertion timing. A scanning current control device for a projection television light source according to claim 1, characterized in that: 3 A photoelectric conversion device having a light receiving section corresponding to the three projection lights is constructed from three elements: an optical fiber common to each projection light source, a three-wave demultiplexer or optical switch, and a photoelectric conversion element, and the three color projection light sources are The insertion timing of the standard signal is made different for each color by an integer multiple of vertical synchronization x 2, and the standard signal is inserted sequentially in time, and the operation of the output section of the photoelectric conversion element or the scanning current control section is synchronized with the standard signal insertion timing. In the case of a configuration using an optical switch, the optical switch is driven in synchronization with standard signals inserted sequentially in time. Scanning current control device for television light source. 4 A photoelectric conversion device with a light receiving section corresponding to the three projection lights is constructed from three elements: an optical fiber common to each projection light source, a three-wave demultiplexer, and a photoelectric conversion element, and the standard signals of each color can be received simultaneously in time. 2. A scanning current control device for a projection television light source according to claim 1, wherein the scanning current control device is inserted into the projection television light source. 5. The light-receiving section or photoelectric conversion device that is sensitive to three colors of projection light is constructed from one that has a wavelength selection function that is sensitive only to each color, and the standard signals of each color are inserted temporally simultaneously. A scanning current control device for a projection television light source according to claim 1. 6. The period of inserting the standard signal and controlling the scanning current is performed for several cycles every integer multiple of vertical period x 2 to complete the control operation, and this operation is repeated as one unit manually or automatically at a predetermined time period. A scanning current control device for a projection television light source according to claim 1, characterized in that: