JPH07236149A - Registration device - Google Patents

Abstract

PURPOSE:To attain highly accurate registration adjustment necessary for a high picture quality projector at a low cost and to easily execute the adjustment by providing this registration device with correction waveform generating means adopting an analog system and a digital system. CONSTITUTION:The registration device is provided with a correction waveform generating system of an analog type consisting of a reference waveform generating part 1 and a matrix circuit 2 and a correction waveform generating system of a digital type consisting of a memory 6, a controller 7 and a D/A converter 8. In the analog type correction waveform generating system, the circuit 2 controls the adding rate of a reference waveform supplied from the generating part 1 to set up a correction value and corrects the registration of the whole picture by the small quantity of data. A corrected waveform having the distortion having a degree higher than quartic is obtained by the digital type correction waveform generating system. Thereby for corrected data, the data obtained by calculation from a distortion component detected by practically picking up a raster image is recorded in an EP-ROM in a production stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a registration device suitable for a projector using a CRT.

[0002]

2. Description of the Related Art FIG. 3 and FIG. 4 show a conventional example as a registration device mounted in a CRT three-tube projector for the purpose of image distortion correction / beam matching of RGB three colors.

First, FIG. 3 shows an analog type registration apparatus, in which 1 is H.SAW (horizontal scanning signal), H.PARA.
(Horizontal parabolic signal), V.SAW (vertical scanning signal),
V.PARA (vertical parabolic signal) ... A fundamental wave generator that generates a fundamental waveform, and 2 are matrix circuits that perform gain adjustment and synthesis of the fundamental waveforms.
Is a controllable element such as a semi-fixed variable resistor or an electronic potentiometer, and controls the registration correction waveform by adjusting the amount of synthesis when combining various basic waveforms supplied from the fundamental wave generator 1. Adjust and output each registration correction waveform.

The registration correction waveform is, for example, each C
It is applied to horizontal and vertical correction deflection yokes (hereinafter referred to as sub DY) arranged on the RTs 5R, 5G, and 5B. That is, the three primary colors (R
GB) correction waveform S _RV for the horizontal and vertical directions,
S _RH , S _GV , S _GH , S _BV and S _BH are amplified by amplifiers 3 _RV , 3 _RH , 3 _GV , 3 _GH , 3 _BV and 3 _BH , respectively, and sub DY4 _RV , 4 _RH , 4 _GV , It is supplied to 4 _GH , 4 _BV and 4 _BH . (The subscripts R, G and B indicate red, green and blue, and H and V indicate horizontal and vertical scanning signals.)

Such an analog type registration device has a relatively simple structure and can be realized at a low cost, and is therefore widely used in projectors for general household use.

On the other hand, FIG. 4 shows an example of a digital type registration apparatus, 6 is a memory such as EP-ROM, 7 is a controller, and 8 is a D / A converter.
In this case, the controller 7 transfers the data stored in the memory 6 to the D / A converter 8 to convert it into an analog waveform,
The waveforms are used as registration correction waveforms S _RV , S _RH , S
_GV , _SGH , _SBV , _SBH .

That is, the correction waveforms S _RV , S _RH , S _GV , S _GH ,
S _BV and S _BH are amplifiers 3 _RV , 3 _RH , 3 _GV and
Amplified by 3 _GH , 3 _BV , 3 _BH , sub DY4 _RV , 4 _RH ,
It is supplied to 4 _GV , 4 _GH , 4 _BV and 4 _BH . In this digital registration device, the correction data stored in the EP-ROM is divided into the number of screen divisions (= the number of adjustment points).
It has the advantage that even higher order distortions can be corrected by increasing it.

[0008]

By the way, in recent years, CRTs have been used.
In a three-tube type projector using a CRT, an inner surface r tube is used in order to reduce the size of the projector device.
However, there is a situation in which the optical system from the CRT to the screen is of an oblique projection type, but complicated image distortion occurs due to these techniques.

FIG. 5 (a) shows a flat CRT having a substantially flat tube surface, and FIG. 5 (b) shows a CR.
3 shows an inner surface r-type CRT in which the tube surface of T is concave. The radius of curvature R of the inner surface r in FIG. 5B is assumed to be approximately 5 times the distance L from the deflection center (R = 5L). The inner surface r-type CRT shown in FIG. 5 (b) is more suitable for downsizing of the projector than the flat-type CRT due to the characteristic of short focus, and has an advantage that high brightness can be measured even in the peripheral portion of the projected image. .

Considering the case where both of these CRTs are used with a deflection of 80 ° (± 40 °), the deflection sensitivity of the peripheral portion of the flat type CRT of FIG. 70% increase, while inner surface r
With a type CRT, it will increase by 124%.

That is, the tendency of the image distortion generated in the flat panel CRT is as follows with respect to the deflection angle θ from the center.

[Equation 1] On the other hand, in the case of the inner surface r-type CRT,

[Equation 2] Therefore, a fairly complicated distortion tendency occurs. Therefore, in the flat CRT, the image distortion can be almost corrected by the correction waveforms of the second and third orders, whereas in the inner surface r-type CRT, the correction cannot be sufficiently performed even by using the correction waveform of the fourth order.

For reference, a flat CRT and an inner r-type CRT
An example of the raster shape of the CRT tube surface when RT is used under the same conditions (deflection angle ± 36 ° in H direction, ± 27 ° in V direction) and without correction is shown in Figs. 6 (a) and (b). Show (inner surface r
The curvature R of the tube surface of the mold CRT is R = 5L with respect to the distance L from the deflection center. As shown in Fig. 6 (b), the inner surface r-type CR
At T, the image distortion becomes larger than the image distortion in the flat panel CRT shown in FIG. 6A, and thus a larger correction is required.

In addition to the adoption of the inner surface r-type CRT, an oblique projection optical system has been adopted as a technique suitable for downsizing the projector. FIG. 7A shows a direct projection optical system, and FIG. 7B shows an oblique projection optical system, which is a projection optical system from each type of CRT to the screen SC. M is a mirror and LZ is a lens. It can be seen from this drawing that the size (X ₂ × Y ₂ ) of the oblique projection optical system can be made smaller than the size (X ₁ × Y ₁ ) of the direct projection type optical system.

Considering the case where the oblique projection optical system of FIG. 7 (b) is adopted, in order to display without distortion on the screen SC, the raster shape on the CRT tube surface is the direct projection type optical system. It is necessary to distort the trapezoid vertically rather than the case.

FIG. 8A shows a case of a direct projection type optical system, which is a raster shape on a CRT tube surface for displaying without distortion on the screen SC, while an oblique projection optical system is used. CR for displaying without distortion on the screen SC
The raster shape on the T tube surface must be as shown in FIG. 8 (b).

That is, in the case where the oblique projection optical system is adopted, in the case of the raster in the flat type CRT, FIG.
8A to FIG. 8B must be corrected, and in the case of an inner surface r-type CRT, FIG. 6B to FIG. 8B
Must be corrected as. Further, even in the case of the direct projection optical system, in the case of the inner surface r-type CRT, it must be corrected as shown in FIGS. 6 (b) to 8 (a). In other words, by adopting the inner surface r-type CRT or adopting the oblique projection optical system as described above, it is necessary to increase the correction processing load on the registration device and generate a high-order correction waveform. Is becoming.

Now, considering an analog type registration apparatus as shown in FIG. 3, many kinds of adjustment items are required to correct complicated image distortion, and adjustment takes time / time. . Further, in the analog method, it is difficult to create a correction waveform having a high order, and it is impossible to correct very high-order distortion. Therefore, it is necessary to loosen the allowable range of registration adjustment, which causes a problem that image quality is deteriorated, which is not suitable for a high image quality type projector such as a high-definition television.

On the other hand, a digital system as shown in FIG. 4, that is,
In the registration device that divides the screen into a large number of points, stores the adjustment data of each point in a memory, etc., and sequentially obtains a corrected waveform by D / A converting it,
If you increase the number of screen divisions (= number of adjustment points) and create the corresponding correction data, you can correct as many distortions as possible.

However, the registration device for correcting the image distortion only by the digital method has a disadvantage that it requires a high-accuracy D / A converter and a large-capacity memory by expanding the dynamic range, so that the cost is high. , It is not appropriate to use it for models for general households. Especially in the case of high quality models such as high definition,
Vertically 14-bit (S / N = 80 dB or more) D / A
A converter is required, which is very expensive.

Further, if the number of adjustment points is simply increased only by the digital method, there is a problem that adjustment takes time and it is difficult to maintain linearity. Most of the image distortion is composed of elements such as linearity, pin distortion, and trapezoidal distortion.In order to correct such distortion of the entire screen, the analog method is easier to adjust. I will end up.

That is, the conventional analog type or digital type registration device has advantages and disadvantages, and it has been impossible to perform highly accurate registration correction at low cost. There was also a problem that the ease of adjustment work was not realized.

[0022]

In view of the above problems, the present invention provides highly accurate registration adjustment required for a high image quality projector at low cost and simplifies the adjustment. The purpose is.

Therefore, as the registration device mounted on the projector using the CRT, the first correction waveform generating means for outputting the correction waveform based on the waveform output from the analog waveform generating part, and the digital waveform generating part. Second, which outputs a correction waveform based on the waveform output from
The correction waveform generating means and the correction output means for mixing the outputs of the first and second correction waveform generating means and applying them to the deflection yoke.

At this time, the first correction waveform generating means generates the registration correction waveform of the third order or lower, and the second correction waveform generating means generates the registration correction waveform of the fourth order or higher. To

Further, such a registration device is mounted on a projector using a CRT which is an inner surface r tube.

Further, such a registration device is installed in a projector in which the optical system from the CRT to the screen is of an oblique projection type.

[0027]

By providing the first correction waveform generating means of the analog type and the second correction waveform generating means of the digital type as described above, most of the image distortion is roughly analog type (that is, the first correction waveform). (Corrected waveform by generating means)
After the correction is performed in step (1), only the remaining detail distortion may be adjusted digitally (that is, the correction waveform generated by the second correction waveform generation means), and the adjustment time can be shortened. And further,
Since the adjustment range by the digital method, that is, the second correction waveform generating means can be reduced, the accuracy of the D / A converter may be low, and the required memory capacity can be considerably reduced.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A registration apparatus according to an embodiment of the present invention will be described below with reference to FIGS. FIG. 2 shows a CRT 3 equipped with the registration device of this embodiment.
It is a block diagram showing an example of a circuit configuration of a tube-type rear projector.

In this figure, 11 indicates a sync separation circuit. A horizontal synchronizing signal H and a vertical synchronizing signal V are extracted from the video signal input to the sync separation circuit 11, and the horizontal synchronizing signal H forms a scanning signal in the horizontal oscillating circuit 13, and a red signal is output via the horizontal deflection output circuit 14. CRT5R, green CRT5G,
It is supplied to the main deflection coils 15R, 15G, and 15B attached to the neck portion of the blue CRT 5B. Similarly, the vertical synchronizing signal V is also supplied to the deflection coils 15R, 15G and 15B via the vertical oscillation circuit 16 and the vertical deflection output circuit 17.

A high voltage is applied from the horizontal oscillation circuit 13 to the anode electrodes of the CRTs 5R, 5G and 5B via the high voltage output circuit 18. In addition, the horizontal deflection output circuit 1
4. The vertical deflection output circuit 17 outputs data for generating a correction wave to the registration correction waveform generator 19. Registration correction waveform generator 19
The correction waveforms of the respective colors output from the CRT 5R, 5 are amplified by the registration output unit 20, respectively.
It is supplied to the sub-DY 4R, 4G, 4B arranged near the G, 5B deflection coils 15R, 15G, 15B.

The video signal which has been subjected to various kinds of signal processing in the video signal processing circuit 12 is amplified by the video output section 21 for each of R, G and B signals to obtain a red CRT 5R and a green CR.
It is supplied to the cathode electrode terminals of T5G and blue CRT5B.

In such a configuration, the registration correction waveform generator 19 and the registration output unit 20 are the registration device of this embodiment. That is, the registration correction waveform generator 19 and the registration output unit 20 are configured as shown in FIG.

In FIG. 1, the same parts as those in FIGS. 3 and 4 described above are designated by the same reference numerals. This registration device has a correction waveform generation system of an analog type including a basic waveform generation unit 1 and a matrix circuit 2 as in FIG.
As in FIG. 4, the memory 6, controller 7, D / A
A digital correction waveform generation system including a converter 8 is provided.

Then, the correction waveforms S _RV1 , S _RH1 , S _GV1 , S _GH1 , S _BV1 obtained by the analog correction waveform generating system are
Addition circuits 9 _RV , 9 _RH , and S _BH1 and correction circuits S _{RV 2} , S _RH2 , S _GV2 , S _GH2 , S _BV2 , and S _BH2 obtained by the digital correction waveform generation system are respectively added.
9 _GV , 9 _GH , 9 _BV , 9 _BH , and this adder circuit 9 _RV , 9
The outputs of _RH , 9 _GV , 9 _GH , 9 _BV and 9 _BH are amplified by amplifiers 3 _RV , 3 _RH , 3 _GV , 3 _GH , 3 _BV and 3 _BH , respectively, and sub DY4 _RV , 4 _RH and 4 _GV , 4 _GH , 4 _BV , 4 _BH . In other words, the registration device of this embodiment has a hybrid structure using a digital method and an analog method.

The operation of the registration apparatus of this embodiment when actually performing registration adjustment will be described. First,
Use the analog correction waveform generation system to make rough registration adjustments. In the analog correction waveform generation system, since the matrix circuit 2 adjusts the addition ratio of the basic waveforms supplied from the basic waveform generation unit 1 to set the correction amount, the registration of the entire screen is reduced by a small amount. There is a feature that it can be corrected with data, and if rough registration adjustment is performed, the adjustment time can be short. The basic waveform for correction includes a predetermined DC component, horizontal and vertical sawtooth waves (SAW), horizontal and vertical parabolic waves, sine waveform, Sin ² waveform and the like.

However, as described above, it is difficult to correct higher-order distortion such as image distortion at the screen corner that occurs when an internal r-type CRT is used in the analog correction waveform generation system. In order to do so, it is necessary to increase the number of types of adjustment items, which requires skill and time for operation. Therefore, in the present embodiment, the analog correction waveform generation system merely makes a rough registration adjustment, and generates a correction waveform based on, for example, a 0th to 3rd order waveform.

The correction waveforms of higher-order distortion of the fourth order or higher are generated by the digital correction waveform generation system circuit. Four
Higher or higher order distortion is capable of correcting, for example, the effect of the distortion magnetic field of the tendency coil and the distortion peculiar to each CRT, and the correction data therefor is actually detected by capturing a raster image. The data obtained by calculation from the distortion component may be recorded in the EP-ROM at the manufacturing stage.

As described above, in this embodiment, the analog correction waveform generation system roughly performs distortion correction of about 75%, and the digital correction waveform generation system performs distortion correction of the remaining about 25%. The correction waveforms S _RV1 , S _RH1 , S _GV1 , S _{GH 1} , S _BV1 , S _BH1 are generated by the waveform generation system, and the correction waveforms S _RV2 , S _RH2 , S _GV2 , S _GH2 , S are generated by the digital correction waveform generation system. _BV2 and _SBH2 are generated.

In the digital method, it is possible to adjust only an arbitrary point, for example, only the peripheral portion of the image, and the remaining distortion corrected by the analog method is corrected by, for example, a slight change of the correction data input in advance. can do. Therefore, there is an advantage that the adjustment time is shorter than that of the analog method for correcting higher-order distortion. In other words, rough adjustment can be performed quickly by analog method,
Furthermore, higher-order distortion can be quickly executed by a digital method.

Further, as long as the number of adjustment points is increased, distortion of high order can be corrected, so that highly accurate registration adjustment can be realized and image quality can be improved.

Assuming that the digital correction waveform generation system performs 25% distortion adjustment as described above, the adjustment range (= dynamic range) required for the digital correction waveform generation system is 25% (full digital 1/4) of the case is sufficient, and the precision of the D / A converter for 2 bits can be reduced as compared with the case of using the all digital method. D /
Decrease the bit precision of the A converter (For example, in high-quality models such as HDTV, the 14-bit D / A converter is
Being able to replace the 2-bit D / A converter) leads to a significant (1/10) reduction in the cost of the D / A converter. Further, in this case, the capacity of the memory 6 for storing the adjustment data can be reduced by 14%, which also leads to cost reduction.

Furthermore, the present applicant has previously proposed a D / A converter as shown in FIG. 9 (Japanese Patent Application No. 5-97282).
No.), which is an 8-bit D / A converter 41 for converting 12-bit data into an analog signal.

That is, the 4-bit counter 51 is operated by using the clock A which is 16 times as large as the 12-bit data update to generate 16 timings, and the LSB 4-bit data of the 12-bit data generated by the data generator 40 is generated. The pulse width corresponding to is generated by the RS latch 52, and the adder 53
At, the MSB is added to the 8-bit LSB. The 8-bit D / A converter 41 is operated with this data. In this case, the set signal of the RS latch 52 is generated when the value of the 4-bit counter 51 is "0", and the reset signal is generated when the value of the LSB 4 bit and the value of the counter 51 are equal to each other. Pulse width is L
It is proportional to SB 4-bit data. If a D / A converter using such a technique is used (that is, a signal having a required resolution is obtained using a D / A converter having a resolution smaller than the required resolution), the cost of the present invention is further increased. Down can be realized.

The present invention can be applied to a direct-viewing type display device using a CRT as well as an image distortion correction / RGB beam color matching circuit (convergence circuit). Further, the present invention is not limited to the above-mentioned embodiment, and various changes may be made to the actual circuit configuration and the like within the scope of the present invention.

[0045]

As described above, the registration apparatus of the present invention has both analog type correction waveform generating means and digital type correction waveform generating means, and the outputs of these two circuits are electrically combined. Is used to perform image distortion correction in the projector and color matching of RGB beams, which makes it possible to perform registration adjustment at relatively low cost, high accuracy, easy operation, and short time. There is.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a registration device of the present invention.

FIG. 2 is a block diagram of a projector including the registration device according to the embodiment.

FIG. 3 is a block diagram of an analog type registration device.

FIG. 4 is a block diagram of a digital registration device.

FIG. 5 is an explanatory diagram of a flat CRT and an inner surface r-type CRT.

FIG. 6 is an explanatory diagram of raster distortion in a planar CRT and an inner surface r-type CRT.

FIG. 7 is an explanatory diagram of a direct projection type optical system and an oblique projection type optical system.

FIG. 8 is an explanatory diagram of a raster shape on a CRT tube surface when image distortion on a screen is corrected in a direct projection type optical system and an oblique projection type optical system.

FIG. 9 is an explanatory diagram of a D / A converter of the prior art.

[Explanation of symbols]

1 Basic Waveform Generator 2 Matrix Circuit 3 _RV , 3 _RH , 3 _GV , 3 _GH , 3 _BV , 3 _BH Amplifier 4 _RV , 4 _RH , 4 _GV , 4 _GH , 4 _BV , 4 _BH Sub DY 5R, 5G, 5B CRT 6 memory 7 controller 8 D / A converter 9 _RV , 9 _RH , 9 _GV , 9 _GH , 9 _BV , 9 _BH adder circuit

Claims (4)

[Claims] 1. A registration device mounted on a projector using a CRT, comprising: first correction waveform generating means for outputting a correction waveform based on a waveform output from an analog waveform generating part; and a digital waveform generating part. Second correction waveform generating means for outputting a correction waveform based on the output waveform, and correction output means for mixing the outputs of the first and second correction waveform generating means and applying them to the deflection yoke. A registration device comprising: 2. A registration correction waveform having a tertiary waveform or less is generated by the first correction waveform generating means, and a registration correction waveform having a quaternary waveform or more is generated by the second correction waveform generating means. The registration device according to claim 1. 3. The registration device according to claim 1 or 2, which is a registration device mounted on a projector using a CRT having an inner surface r tube. 4. The registration device according to claim 1, wherein an optical system from the CRT to the screen is a registration device mounted on a projector of an oblique projection system.