JPH07121128B2 - Convergence device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for correcting the convergence of a rear projection type television receiver, and more particularly to a convergence device that can be adjusted quickly and accurately.

2. Description of the Related Art Generally, in a color television receiver, there are three types of red, green and blue.
An image is created by synthesizing colors on a fluorescent surface or on a projected screen. In this case, accurate alignment of the three colors, that is, convergence adjustment is an important issue affecting image quality.

Here, the deviation in convergence will be described by taking a projection type color television receiver as an example.

In FIG. 5, reference numeral 1 denotes a projection screen for displaying an image. Reference numerals 2, 3 and 4 are projection type picture tubes having an optical lens for forming the image obtained on the fluorescent surface on the projection screen 1, and three images of red, green and blue are provided on each fluorescent surface. Is obtained. As shown in FIG. 5, when these picture tubes are arranged in the horizontal direction, the projection angles with respect to the projection screen 1 are different from each other, and thus the projected raster has a positional deviation as shown in FIG. 6 for each color. . In FIG.
A solid line 3l indicates a raster of the green light picture tube 3, a covered line 4l indicates a projection raster of the blue light picture tube 4, and a chain line 2l indicates a projection raster of the red light picture tube 2. In order to correct this positional deviation, a coil for convergence adjustment is provided separately from the main deflection yoke on the image-receiving type picture tubes 2, 3 and 4, and the sawtooth wave current of the horizontal scanning cycle is amplitude-modulated in the vertical cycle, and each color is adjusted. The amplitude can be adjusted independently with. However, this color shift amount changes due to variations in the mounting positions of the respective picture tubes, variations in the configuration of the optical lens system, variations in the projection screen position, etc. Therefore, in order to perform highly accurate convergence adjustment, it is necessary to use a mere sawtooth wave. It is not possible with a combination of electric current and parabolic current.

As a method for realizing such convergence adjustment, a convergence circuit having a digital correction wave forming unit is considered.

The conventional convergence device will be described in detail with reference to FIG.

Horizontal and vertical periodic pulses, which are periodic in the deflection current period, are added as synchronization signals to drive the read address control unit 5. The crosshatch pattern generator 6 is driven by using the pulse from the read address control unit 5 to project the crosshatch pattern on the projection screen. On the other hand, the address key of the control panel 12 is used to specify the cross point of the position where the convergence correction is required, and the position address is set in the write address control unit 8. Next, the correction amount is written in the one-frame memory 10 through the data reversible counter 11 while looking at the screen with the data write key of the color to be corrected, for example, the red data write key provided on the control panel 12. Normally, the writing in the 1-frame memory is switched and controlled by the multiplexer 9 so as to be performed during the blanking period of the video signal. Therefore, reading is not impaired. The same operation is performed at each adjustment point as described above. Next, the reading of the 1-frame memory is performed by the read address control unit 5 at the cross position of each cross hatch on the screen, and through the register 18 driven by the read address control unit 5, the vertical direction insertion processing is performed. In the unit 13, the vertical scanning line between the cross hatches, that is, the correction amount for each scanning line in which the correction amount is not stored is obtained by, for example, linear approximation. Then, the output signal is converted into an analog amount by the D / A conversion unit 14. Next, the correction amount in the horizontal direction is smoothed through the resistance pass filter (LPF) 15, and the correction current is added to the convergence output unit 16 to supply the correction current to the convergence coil 17. Convergence adjustment of each adjustment point is performed as described above.

Problems to be Solved by the Invention However, in the configuration as described above, since each adjustment point can be independently corrected, it is possible to perform convergence correction with high accuracy, but it is necessary to adjust the adjustment points for each color and the entire screen.
There is a problem that it takes a very long time to adjust the convergence accurately.

In view of the above point, the present invention has an object to provide a convergence device that automatically performs convergence adjustment on the entire screen in a short time.

The present invention relates to a display means for displaying a signal for generating a plurality of convergence adjustment points horizontally and vertically on a display screen of a transmissive screen of a rear projection type television receiver, and the adjustment means. A unit for inputting position information of a point, a focusing lens provided on the screen, and a signal for generating the adjustment point provided on a portion of the transmissive screen having a low transmittance other than the lens are received and the position of the signal is determined. A photoelectric conversion element for detecting, a detection means for detecting a signal position by the photoelectric conversion element provided on the screen, a comparison means for comparing a detection signal of the detection means with a reference position, and a convergence by a signal from the comparison means. Generating means for generating a convergence correction amount for correcting the deviation, and storage means for digitally storing the convergence correction amount, Convergence apparatus comprising the storage means and reading means for reading out the convergence correction amount in response to the synchronization signal of the receiver.

Effect The present invention has the above-described configuration, and it is possible to automatically perform high-precision convergence adjustment on a full screen in a short time while displaying a high-contrast image without impairing the original performance of the transmissive screen.

Practical Example FIG. 1 shows a principle block diagram of a convergence device in a first example of the present invention. In FIG. 1, 25 is a projection type picture tube, 28 is a projection lens, 26 is a deflection yoke, and 29 is a first.
A mirror, 30 is a second mirror, and 31 is a transmission screen provided with a photoelectric conversion element 34. Further, reference numeral 19 drives the projection type picture tube 25 by increasing the amplitude of the video signal arrived at the video signal input terminal to the required amplitude by the video circuit 21. The video circuit 21 operates in the same manner as an ordinary receiver, but the crosshatch signal created by the digital convergence circuit 22 is supplied and is displayed at the time of convergence adjustment. Further, the deflection circuit 23 and the deflection yoke 26
Then, the electron beam of the projection type picture tube 25 is scanned by the synchronizing signal which arrives at the synchronizing signal input end of 20. Although only one projection type picture tube 25 is shown in FIG.
Three green and blue picture tubes are used.

The present invention displays a crosshatch signal on the screen, detects the convergence deviation of each adjustment point by the photoelectric conversion element 34 on the transmissive screen 31 provided at the position corresponding to each adjustment point, and uses the signal to detect digital convergence. Circuit 22
The amount of correction is changed to automatically adjust the convergence. The transmissive screen 31 is composed of a diffusion plate having a lenticular lens 33, a Fresnel lens 32 for concentrating the light in the peripheral portion in the center, and a portion with low transmittance other than the lens portion. A conversion element 34 is provided. The element 34 receives the crosshatch signal displayed on the screen 31 and transmitted through the screen 31, and at the same time blocks the transmission of light to the surface opposite to the incident side. That is, the installation portion of the element 34 is a portion having a low light transmittance which is so-called black stripe in which light transmission hardly occurs.

A block diagram of the present invention is shown in FIG. 2, and the same operations as those in FIGS. 1 and 7 are designated by the same reference numerals and the description thereof will be omitted. Further, the operation of the embodiment will be described with reference to the screen diagram and waveform diagram of FIG. FIG. 3 (a) shows a screen 31 on which a photoelectric conversion element 34 is arranged at a position corresponding to 63 adjustment points in 9 rows in the horizontal direction and 7 columns in the vertical direction in a portion having low transmittance. It is provided. First, the green crosshatch signal shown by the solid line in FIG. When the adjustment point A shown in FIG. 3 (a) is designated by the write address control unit 8, the signal from the crosshatch generator 7 is only in the vicinity of the adjustment point A as shown in FIG. 3 (a). Only the crosshatch signal is output, and the position of the green crosshatch signal (reference signal) is detected by the photoelectric conversion element 34 provided on the transmissive screen 31. Next, a horizontal convergence adjustment method will be described in detail. First, the color signal switching is performed by the color signal switch 37, and the crosshatch signal of the line shown by the solid line in FIG.
The red crosshatch signal indicated by the broken line in FIG. The signal is photoelectrically converted by the photoelectric conversion element 34, and the green crosshatch signal becomes as shown in FIG. 3 (b). The clock pulse which is this signal is counted and the reference signal position counter is counted.
Set 27. The photoelectrically converted red crosshatch signal is shown in FIG. 3 (b), and the clock pulse is counted by this signal to set the comparison signal position counter 35.
Then, the comparator 37 compares the contents of the reference signal position counter 27 indicating the green crosshatch signal position and the contents of the comparison signal position counter 35 indicating the red crosshatch signal position, and the data reversible counter 11 is displayed until both counters match. move. Then, as described in the conventional example, the correction data of the one-frame memory 10 is changed to move the red crosshatch signal position shown in FIG. 3B from point B to point C. This means that the horizontal green and red convergence adjustments have been made. Similarly, in the blue horizontal convergence adjustment of the adjustment point A, the blue crosshatch signal of the adjustment point A is displayed by the color signal switch 36 during the third field scanning, and the same operation as described above is performed. Go on and adjust the blue horizontal convergence.

Next, in the vertical direction convergence adjustment of each color, as in the horizontal direction, the contents of the reference signal position counter and the comparison signal counter are compared in the vertical cycle, and the data reversible counter 11 is operated until both counters match. The correction data in the frame memory 10 is changed to perform vertical convergence adjustment. In this case, the structure is the same as that shown in FIG. 2, but a reference signal position counter having a vertical cycle and a comparison signal counter are required.

As described above, the horizontal / vertical convergence adjustment of the adjustment point A of FIG. 3 (a) designated by the write address control unit 8 is performed, and thereafter, each other adjustment is designated by the designation of the write address control unit 8. You can adjust the horizontal and vertical convergence of points. 1 frame memory
The reading of the correction data written in 10 is the same as that in the conventional example, and thus the description thereof is omitted. 1 frame memory 10
Since it is necessary to read the corresponding to the screen,
Reading is performed in synchronization with horizontal and vertical deflection.

As described above, according to the present embodiment, the photoelectric conversion element is provided in the low transmittance portion of the transmission screen of the rear projection type television, and the signal position of each color is detected by the photoelectric conversion element, with high accuracy, And convergence can be adjusted automatically.

FIG. 4 is a block diagram of a transmissive screen of a convergence device showing a second embodiment of the present invention. In the figure, 32
Is a Fresnel lens, 33 is a lenticular lens, and the above is the same as the configuration of the transmission screen 31 in FIG. The difference from the configuration of FIG. 1 is that the photoelectric conversion element 34 is provided on the black stripe 37. The operation of the second embodiment is the same as that of the first embodiment, so the description thereof is omitted. In the case of this example, a black stripe made of a light absorber different from the element 34 is formed on the surface opposite to the light receiving surface of the element 34, and a more reliable portion without light transmission can be formed as compared with FIG.

As described above, according to the present embodiment, the photoelectric conversion element is provided in the black stripe portion of the transmissive screen of the rear projection television, and the signal position of each color is detected by the photoelectric conversion element. Convergence adjustment can be performed automatically, and an image with good contrast can be displayed.

In the first embodiment, the convergence adjustment uses the green signal as the reference signal and superimposes the red signal and the blue signal on the reference signal green signal. However, a separate reference signal is provided and the green signal is added to the reference signal. Red and blue signals may be superimposed.

The shape of the photoelectric conversion element is a quadrangle for easy understanding of the operation, but other shapes such as a cross shape, a cross shape, and a V shape may be used.

As described above, according to the present invention, a signal for generating a plurality of convergence adjustment points in the horizontal and vertical directions is displayed on the display screen of the transmissive screen, so that the convergence adjustment of the full screen is automatically performed. The adjustment can be done in a short time regardless of the skill level of the operator.
Convergence adjustment with high accuracy can be performed.
In addition to the focusing lens of the transmissive screen, a photoelectric conversion element is provided in a portion with low light transmittance, which can be said to be a black stripe, and the signal is received by the photoelectric conversion element. With this, it becomes possible to display an image with good contrast and perform convergence adjustment, which greatly contributes to the convergence adjustment.

[Brief description of drawings]

FIG. 1 is a principle diagram of a convergence device in one embodiment of the present invention, FIG. 2 is a block diagram of the device, FIG. 3 is a screen diagram and waveform diagram for explaining the operation of the device, and FIG. FIG. 5 is a configuration diagram of a transmission screen of a convergence device according to another embodiment of the present invention, FIG. 5 is a principle diagram showing the principle of a projection television receiver, and FIG. 6 is a diagram for explaining the convergence deviation. The figure is a block diagram of a conventional convergence device. 31 …… Transparent screen, 34 …… Photoelectric conversion element, 37 …… Black stripe, 27 …… Reference signal position counter, 35…
… Comparison signal position counter, 37 …… Comparator, 11 …… Data reversible counter, 36 …… Color signal switching unit, 8 …… Write address control unit, 5 …… Read address control unit, 7 ……
Crosshatch generator, 10 …… 1 frame memory.

Claims (1)

[Claims] 1. A display means for displaying a signal for generating a plurality of convergence adjustment points in the horizontal and vertical directions on a display screen of a transmission screen of a rear projection type television receiver, and position information of the adjustment points. Input means, a focusing lens provided on the transmissive screen, and a signal for generating the convergence adjustment point, which is provided in a black stripe region having a low transmittance other than the lenses of the transmissive screen, and receives the position of the signal. A photoelectric conversion element for detecting, a detection means for detecting a signal position by the photoelectric conversion element, a comparison means for comparing a reference position of a detection signal of the detection means, and a convergence for correcting a convergence deviation by a signal from the comparison means. Generating means for generating a correction amount, and storage means for digitally storing the convergence correction amount Convergence device provided with reading means for the memory means reads the convergence correction amount in response to the synchronization signal of the receiver.