JPS6211389A - Convergence device - Google Patents

Abstract

PURPOSE:To attain automatic adjustment of convergence with high accuracy by providing photoelectric transfer elements at parts where the transmission rate is low of the translucent screen of a rear projection type television, and detecting the locations of signals by the elements. CONSTITUTION:The photoelectric transfer elements 34 are provided at such locations as corresponding to the adjusting points of the screen 31 where the transmission rate is low, nine lines in horizontal direction and 7 columns in vertical direction, total sixty-three. If an adjusting point A is specified against a write address control part 8, only the cross hatch signals close to the said point A are outputted from a cross hatch generator 7, and a green cross hatch signal is detected by the elements 34. During a second field scanning time, a red cross hatch signal shown by the broken line is outputted. Clock pulses are counted using these signals to set a reference signal location counter 27 and a comparison signal location counter 35. A data reversible counter 11 is moved until the said both counters coincide with each other, and the red cross hatch signal location is transferred from point B to point C by changing the correction data in a 1-frame memory 10.

Description

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

Conventional technology Generally, color television receivers have red and green.

An image is created by combining the three colors of blue on a fluorescent surface or a projected screen, but in this case, accurate alignment of the three colors and convergence adjustment are important factors that affect image quality. It becomes a challenge.

Here, the convergence deviation will be explained using a projection type color television receiver as an example.Q In FIG. 5, 1 indicates a projection screen on which images are projected. Reference numerals 2, 3, and 4 refer to a projection type picture tube equipped with an optical lens that forms an image obtained on a fluorescent surface onto the projection screen 1, and each fluorescent surface has three-color images of red, green, and blue. is obtained. When these picture tubes are arranged horizontally as shown in Figure 5, the projection angles relative to the projection screen 1 are different, so the projected raster will be misaligned for each color as shown in Figure 6. . In FIG. 6, the solid line 3t is a raster generated by the picture tube 3 of green light, and the broken line 4
t is the projection raster by the picture tube 4 of blue light, and the dashed line 2t
shows a raster projected by the picture tube 2 of red light. To correct this positional shift, a convergence adjustment coil is installed in the projection picture tube 2.3.4 separately from the main orientation yoke, and the sawtooth wave current in the horizontal scanning period is amplitude-modulated in the vertical period. The amplitude can be adjusted independently. however,
The amount of color shift varies due to variations in the mounting position of each picture tube, variations in the configuration of the optical lens system, variations in the projection screen position, etc., so in order to perform high-precision convergence adjustment, it is necessary to use a simple sawtooth waveform. This is not possible with electric currents or combinations of parabolic currents.

As a method for realizing such convergence adjustment, a convergence circuit having a digital correction waveforming section has been considered.

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

Horizontal and vertical period pulses synchronized with the deflection current period are added as synchronization signals, thereby driving the read address control section 5. The pulse from the read address control section 5 is used to drive the crosshatch pattern generator 6 to project a crosshatch pattern on the projection screen. On the other hand, with the address key on the control panel 12,
A cross point at a position requiring convergence correction is designated, and a position address is set in the write address control unit 8. Next, using the data write key of the color to be corrected, for example, red provided on the control panel 12, write the correction amount into the one frame memory 10 through the data reversible counter 11 while looking at the screen. Normally, writing to the one frame memory is controlled by switching by the multiplexer 9 so that it is performed during the blanking period of the video signal.

Therefore, the readout will not be impaired. Perform the same operation at each adjustment point as above 10 〇th order V:, 1
Reading of the frame memory is performed by the readout address control section 5 for the cross position of each crosshatch on the screen, and through the register 18 driven by the readout address control section 6, the data is read out by the vertical interpolation processing section 13.
Then, the correction amount for each vertical scanning line between crosshatches, that is, for each scanning line for which no correction amount is stored, is determined by, for example, linear approximation. Next, the output signal is D/A
The conversion unit 14 converts it into an analog quantity. Next, the correction amount in the horizontal direction is smoothed through a resistance pass filter (LPF) 15, and is applied to a convergence output section 16 to supply a correction current to a convergence coil 17. Convergence adjustment at each adjustment point is performed as described above.

Problems to be Solved by the Invention However, with the above configuration, each adjustment point can be corrected independently, so convergence correction can be performed with high accuracy; however, since adjustment of the adjustment points of each color and the entire screen is required,
There is a problem in that it takes a very long adjustment time to perform convergence correction with high accuracy.

In view of this point, it is an object of the present invention to provide a convergence device that automatically performs convergence adjustment.

Means for Solving the Problems The present invention provides means for providing a photoelectric conversion element in a low transmittance portion of a transmission screen of a rear projection TV receiver, and means for detecting a signal position using the photoelectric conversion element provided on the screen. a comparison means for comparing the detection signal and a reference signal; a generation means for generating a convergence correction amount for correcting a convergence shift based on the signal from the comparison means; and a storage means for digitally storing the convergence correction amount. and reading means for reading out a convergence correction amount from the storage means in response to a synchronization signal of a receiver.

Function The present invention provides a photoelectric conversion element in a low-transmittance part of the transmission screen of a rear projection television with the above-described configuration, and detects the signal position with this photoelectric conversion element, thereby accurately and automatically detecting the signal position. FIG. 1 shows the basic configuration of the convergence device in the first embodiment of the present invention. In FIG. 1, 25 is a projection type picture tube, and 2B is a projection tube. lens, 26 is a deflection yoke,
29 is a first mirror, 3o is a second mirror, and 31 is a transmission screen provided with a photoelectric conversion element 34.0 and 19 are video signals that arrive at the video signal input terminal and are amplified to the required amplitude by the video circuit 21. The projection picture tube 26 is driven. The video circuit 21 operates in the same manner as a normal television receiver, but a crosshatch signal created by a digital convergence circuit 22 is supplied and displayed during convergence adjustment.

Further, the electron beam of the projection picture tube 26 is scanned by the synchronization signal arriving at the synchronization signal input terminal of the deflection circuit 23 and the deflection yoke 26 . Although only one projection type picture tube 25 is shown in FIG. 1, three picture tubes of red, green, and blue are actually used.

The present invention projects a crosshatch signal on a screen, detects a convergence shift at each adjustment point using a photoelectric conversion element 34 on a transparent screen 31 provided at a position corresponding to each adjustment point, and uses the signal to detect a convergence shift in a digital convergence circuit. The convergence adjustment is automatically performed by changing the correction amount of 22. The transmission screen 31 is composed of a diffuser plate having a lenticular lens 33 and a Fresnel lens 32 that focuses peripheral light to the center, and one photoelectric conversion element 34 is provided, for example, in a portion with low transmittance.

FIG. 2 shows a block diagram of the present invention. Components that operate in the same way as in FIGS. 1 and 7 are designated by the same numerals and their explanations will be omitted. Further, the operation of the embodiment will be explained using the screen diagram and waveform diagram of FIG. FIG. 3 (-) shows a screen 31, on which photoelectric conversion elements 34 are located at positions corresponding to 63 adjustment points in 9 rows horizontally and 7 columns vertically in areas with low transmittance. It is provided. First, Figure 3 (
9 will be explained with the green crosshatched signal shown as a solid line in -) on the side. When the adjustment point A shown in FIG.
Only the nearby 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 transparent screen 31. Next, the horizontal convergence adjustment method will be explained in detail. First, switching of the color signal is performed by the color signal switch 37, and during the first field scanning, the crosshatch signal shown by the solid line in FIG. ) A red crosshatch signal shown by the broken line is output. The signal is photoelectrically converted by the photoelectric conversion element 34, and a green Kuromeno-Tsuchi signal is generated as shown in FIG. .

The photoelectrically converted red Kuromeno-Tutsi signal is shown in Figure 3 (
), and the comparison signal position counter 35 is set by counting clock pulses using this signal.

Then, the comparator 37 compares the contents of the reference signal position counter 27 indicating the green crosshatch signal position and the comparison signal position counter 36 indicating the red crosshatch signal position, and moves the data reversible counter 11 until both counters match. As explained in the conventional example, 1 frame memory 1
By changing the correction data of o, the red cross-point signal position shown in FIG. 3 (17) is moved from point B to point C.

Now the horizontal green and red convergence adjustment is done. Similarly, in the blue horizontal convergence adjustment at adjustment point A, the color signal switch 36
When scanning the third field, check the blue crossbar at adjustment point A.
The blue horizontal convergence adjustment is performed by displaying the blue signal and performing the same operation as described above.

Next, in the vertical direction convergence adjustment of each color, similarly to the horizontal direction, the contents of the reference signal position counter and the comparison signal counter are compared in the vertical period, and the data reversible counter 11 is moved until both counters match.
Vertical convergence adjustment is performed by changing the correction data in the frame memory 10. In this case, the configuration is similar to that shown in FIG. 2, but a vertical period reference signal position counter and a comparison signal position counter are required.

As described above, the convergence adjustment in the horizontal and vertical directions at the adjustment point A in FIG. You can adjust the convergence of points in the horizontal and vertical directions. The reading of the correction data written in the one-frame memory 1o is the same as in the conventional example, so a description thereof will be omitted. Note that since it is necessary to read out the one frame memory 1° in accordance with the screen, the reading is performed in synchronization with the horizontal and vertical deflections.

As described above, according to this embodiment, a photoelectric conversion element is provided in a low transmittance part of the transmission screen of a rear projection television, and the signal position of each color is detected by the photoelectric conversion element, thereby achieving accurate In addition, convergence adjustment can be performed automatically.

FIG. 4 is a block diagram of a transmission screen of a convergence device showing a second embodiment of the present invention. In the same figure, 3
2 is a Fresnel lens, 33 is a lenticular lens,
The above structure is similar to that of the transparent screen 31 shown in FIG. The difference from the configuration in FIG. 1 is that the photoelectric conversion element 34
is provided on the black stripe 37. Also the second
The operation of this embodiment is the same as that of the first embodiment, so a description thereof will be omitted.

As described above, according to this embodiment, a photoelectric conversion element is provided in the black stripe portion of the transparent screen of a rear projection television, and the accuracy of detecting the signal position of each color by the photoelectric conversion element is improved. Convergence adjustment can be easily and automatically performed, and images with good contrast can be displayed.

In the first embodiment, the convergence adjustment was performed using a green signal as a reference signal and superimposing red and blue signals on the edge signal of the reference signal. Red and green signals may be overlapped.

Further, although the photoelectric conversion element is square in shape to facilitate understanding of its operation, it may be in other shapes such as a cross, a cross, or a V-shape.

As described in detail, according to the present invention, convergence adjustment can be performed automatically, so that adjustment can be performed in a short time regardless of the skill level of the operator, and highly accurate convergence adjustment can be performed. can be done. Furthermore, by providing a photoelectric conversion element in the black stripe portion, an image with good contrast can be projected, which has a great practical effect.

[Brief explanation of drawings]

FIG. 1 is a principle diagram of a convergence device according to an 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. 4 is a diagram of the convergence device. 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, FIG. 6 is a diagram for explaining the convergence deviation, The figure is a block diagram of a conventional convergence device. 31...Transmission screen, 34...Planar photoelectric conversion element, 37...Black stripe, 27...
River/reference signal position counter, 36... Comparison signal position counter, 37... Comparator, 11...
... Data reversible counter, 36 ... Color signal switch, 8 ... Write address control section, 5 ... Song read address control section, 7 ... Crosshatch generator, 10...1 frame memory. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure B OF, 31--One-pass, Swarn 32--7 sequence reference (37--Blacks) Live No. 5rIA Fig. 6

Claims (2)

[Claims] (1) A display means for generating and displaying a plurality of convergence adjustment points in the horizontal and vertical directions on the screen of a rear projection television receiver, an input means for inputting position information of the adjustment points, and a transmission screen. installation means for providing a photoelectric conversion element in a portion of the screen with a low rate; detection means for detecting a signal position by the photoelectric conversion element of the screen; comparison means for comparing the detection signal with a reference signal; and a signal from the comparison means. generating means for generating a convergence correction amount for correcting a convergence shift according to the method; storage means for digitally storing the convergence correction amount; and reading means for the storage means to read out the convergence correction amount in response to a synchronization signal of the receiver. A convergence device equipped with. (2) The convergence device according to claim 1, wherein a photoelectric conversion element is provided in the black stripe portion of the transmission screen as the installation means.