JPH05323892A - Uniformity circuit - Google Patents

Abstract

PURPOSE:To improve the uniformity of a video projector by correcting residual color irregularities of R and B and correcting the brightness of the peripheral part of a screen. CONSTITUTION:Color irregularity correction waveform signals (H: 3rd waveform, V: 2nd waveform) for a horizontal and a vertical synchronizing signal synchronized with main deflection and brightness correction waveform signals (H and V: 2nd waveform) are generated from the horizonta1 and vertical synchronizing signals, and correction waveform signals (R and B: correction of both color irregularity and brightness, G: correction of only brightness) for R, G, and B are generated from those correction waveform signals. Then R, G, and B primary-color signals are modulated with the correction waveform signals for R, G, and B respectively. The primary-color signals modulated with the correction waveform signals are amplified by CRT driving circuits 12, 22, and 32 and projected on CRT fluorescent screens, and their images are enlarged and projected on a screen through projection lenses installed in front of CRTs 11, 21, and 31. The image projected on the screen is reduced in color irregularity and improve in the brightness at the peripheral part of the screen since the color irregularity and brightness of the light output are already corrected.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a three-lens CRT system,
The present invention relates to a uniformity circuit including a color unevenness correction and brightness correction circuit which is one of image quality improving circuits of a rear type or front type video projector using a one-lens CRT system, a three-lens liquid crystal system, or a one-lens liquid crystal system.

[0002]

2. Description of the Related Art A CRT type video projector, regardless of whether it is a rear type or a front type, uses a three-lens projection lens installed in front of a CRT phosphor screen to project a monochromatic image projected on a small R, G, B monochromatic CRT. It is obtained by enlarging and projecting it on a large screen and synthesizing color images on the screen. Therefore, the influence of each part of the optical system (a plurality of projection lenses forming one projection lens), the difference in the mounting angle of the R, G, and B CRTs to the set (difference in the concentration angle), each CRT Due to the difference in the projection distance to the screen, uneven light amounts of R, G and B are optically generated on the screen. When the unevenness of R, G, and B light intensity occurs, when the white raster is displayed on the screen, white becomes reddish in the area where the R light quantity is large, and conversely, white becomes bluish in the area where the B light quantity is large. White is not evenly reproduced above. The above state is called color unevenness. When about 10% color unevenness occurs (a state where about 10% color unevenness remains on the screen), the viewer of the projector feels the color unevenness.

As for the color unevenness that occurs optically as described above, conventionally, the amount of occurrence of color unevenness (residual color unevenness on the screen) is reduced by designing an optical system so as to reduce the color unevenness. I was doing. However, the amount of residual color unevenness cannot be reduced to zero only by designing the optical system, and the residual color unevenness that remains is left unattended and no countermeasure has been taken. The maximum amount of residual color unevenness at this time is 10 to 1
It is about 5%. However, in recent years, the optical projection distance (distance between the projection lens and screen) has been shortened as the depth of rear type video projectors has become thinner,
Even if the color nonuniformity reducing optical system is used, the amount of residual color nonuniformity on the screen becomes larger than that in the case of using the conventional optical system.
About 5% to 25% residual color unevenness occurs. This measure has become necessary.

FIG. 18 shows a conventional optical system (without measures against color unevenness).
FIG. 6 is a diagram showing an example of a ratio of an R illuminance distribution normalized to a G illuminance distribution on a screen in a video projector using the. In the figure, the illuminance distribution ratio of R in the horizontal direction is illustrated with a point on the vertical axis (Y axis) at the center of the screen as a reference point. At this time, when observing the illuminance distribution in the horizontal direction, the left end of the screen is reddest and the right end is bluish. Further, when observing the illuminance distribution in the vertical direction, the amount of residual color unevenness is largest at the upper and lower ends of the screen. This is because the R and B CRTs are installed with a convergence angle α with respect to the G CRT,
This is because the optical distances from the R and B projection lenses to the left and right ends of the screen are different, and the projection distance is different at the left and right ends of the screen. Similarly, the unevenness of illuminance distribution in the vertical direction is because the CRT is installed with the elevation angle θ, and the projection distances from the upper end to the lower end of the screen are different. Since the R and B CRTs are installed with the G CRT as the axis of symmetry, the illuminance distributions on the R and B screens are reversed,
The illuminance distribution of B is the lowest at the left end of the screen and is the highest at the right end of the screen. Since the three CRTs are installed at the same angle (elevation angle) in the vertical direction, the R and B vertical illuminance distributions have the same distribution.

Further, FIG. 19 shows R normalized to an illuminance distribution of G on a screen in a video projector using an optical system designed to reduce residual color unevenness.
FIG. 19 is a diagram showing an example of the ratio of the illuminance distribution of, and is shown based on the point on the Y axis as in FIG. 18. In addition, the distribution of B is the same as that of the conventional optical system, and the distribution of R is left-right inverted as if the Y-axis is symmetrical. Therefore, the left half of the screen becomes reddish and the right half becomes bluish, but almost no residual color unevenness is observed at the left and right ends of the screen. Further, when observed in the vertical direction, the amount of residual color unevenness increases as it approaches the center of the screen, and becomes maximum on the horizontal axis (X axis) of the screen center. However, this optical system uses the axis shifting optical system in which the axes of the projection lenses are shifted so that the angles of view at the left and right ends of the screen of the R and B projection lenses are equal. The maximum amount of residual color unevenness due to this optical system is smaller than the maximum amount of residual color unevenness due to the conventional optical system,
The residual amount is about 10%. (The distance between the projection lens and the screen is about 800m with a 45 ”rear type projector.
If m. However, if the set depth is made thinner, the projection distance will be further shortened, and the amount of color unevenness on the screen will be larger than at present.

FIG. 17 shows a block diagram of a conventional video circuit which does not include a uniformity circuit. In the figure, 1 is a video matrix circuit for demodulating an input video signal into R, G, B primary color signals, 11, 21, 3
1 is a small CRT that displays R, G, B images, 12, 22,
Reference numeral 32 is an output circuit for driving the CRTs 12, 21, 31.

Next, the operation will be briefly described. The video signal is input to the video circuit as a composite signal or a Y / C signal. The video signal input to the video circuit is R, G, B in the matrix of the video matrix circuit 1.
Demodulated to the primary color signal of. The primary color signals of R, G, B are sent to the output stages 12, 22, 32, respectively, and the CRTs 11, 21, 31 of R, G, B are driven to display R, G, B on the CRT phosphor screen. A monochrome image (raster) of B is projected. The image output on the CRT phosphor screen has its light output magnified and projected on the screen by a projection lens (not shown) installed on the front surface of the CRT, and the R, G and B images are optically projected on the screen. A color image is obtained by synthesizing.

Now, considering the case where a white raster signal is input to the video circuit of the projector, R,
Since the electron beam current densities become equal at arbitrary positions of the rasters on the phosphor screens of the G, B CRTs 11, 21, 31 respectively, the brightness of the rasters on the RRT, G, B CRT phosphor screens become equal. The projection lens has a property of lowering the luminance of the peripheral portion of the screen where the angle of view is large due to the cos ⁴ law. Due to this, the luminance of the image on the screen is not constant and the luminance of the peripheral portion of the screen decreases. (Reduction of peripheral / center luminance ratio) In the conventional rear type video projector, the peripheral / center luminance ratio is about 20 to 30%. (In the case of a conventional rear projector in which the total angle of view of the projection lens is approximately 54 °.)

[0009]

As the rear type video projector becomes thinner and thinner, the projection distance between the projection lens and the screen is shortened. Wider than the angle of view of. As a result, the luminance of the peripheral portion of the screen is further reduced as compared with the conventional one, and the peripheral / center luminance ratio is further reduced as compared with the conventional video projector. For example, in a rear type projector with a total angle of view of 80 °, the peripheral brightness of the screen on the screen is about half that of a conventional projector with a total angle of view of 54 °. The ratio drops to around 10%.
When the brightness of the peripheral part is reduced to this level, the viewer of the projector has a problem that not only the residual color unevenness but also the brightness unevenness in the peripheral part of the screen or the hot spot where the center of the screen is bright.

The present invention has been made to solve the above problems, and residual color unevenness caused by shortening the projection distance between the projection lens and the screen accompanying the reduction in depth of the rear type video projector. In addition to reducing the amount, we will improve the deterioration of the peripheral / center luminance ratio caused by the expansion of the angle of view of the projection lens and improve the uniformity. In addition, by using it for conventional video projectors (both rear type and front type), it is an object to obtain a uniformity circuit that can correct residual color unevenness on the screen, which has been left untouched until now, and brightness reduction in the peripheral area of the screen. And

[0011]

A uniformity circuit according to the present invention modulates an R, G, B primary color video signal with a color nonuniformity correction waveform signal or a luminance correction waveform signal, or a composite correction waveform signal of both, and R , G, B by controlling the amount of beam current flowing in the CRT to control the luminance output on the CRT phosphor screen so that a uniform R, G, B illuminance distribution can be obtained on the screen. ..

Alternatively, by modulating a signal applied to G1 of an R, G, B CRT with a color unevenness correction waveform signal or a luminance correction waveform signal, or a combined correction waveform signal of both, R, G, B are respectively obtained. The amount of beam current flowing in the CRT is controlled to control the luminance output on the CRT phosphor screen so that a uniform R, G, B illuminance distribution can be obtained on the screen.

Alternatively, by appropriately combining the above two methods, the amount of beam current flowing in the R, G, and B CRTs is controlled, and the luminance output on the CRT phosphor screen is controlled so as to be uniform on the screen. This is carried out by obtaining an R, G, B illuminance distribution.

[0014]

Since the color unevenness and luminance correction waveform signal in the present invention is created by the product of the correction waveform signals of the horizontal and vertical periods which are synchronized with the horizontal and vertical main deflections similarly to the convergence correction, the dynamic waveform corresponding to the screen position is dynamically generated. Color unevenness and brightness correction can be performed.

[0015]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a video matrix circuit for demodulating an input video signal into R, G, B primary color signals, 2 is a modulation circuit for modulating a video signal with a correction waveform signal to create a correction signal, and 4 is a correction signal And an adder circuit for adding the primary color signals, and 11, 21, and 31 are CRs of R, G, and B for displaying images.
T, 12, 22, and 32 are R, G, and B CRTs 12, 2
2, 32 drive circuits, 13, 23, 33 correction circuits for correcting R, G, B primary color signals composed of the modulation circuit 2 and the addition circuit 4, 16, 26, 36 correction waveforms for R, G, B A signal generation circuit, 45 is a luminance correction waveform signal generation circuit for generating R, G, B luminance correction waveform signals, 46 is a color unevenness correction waveform signal generation circuit for generating R, B color unevenness correction waveform signals, and 40 is This is a color unevenness / luminance correction waveform signal generation circuit constituted by a brightness correction waveform signal generation circuit 45, a color unevenness correction waveform signal generation circuit 46, and correction waveform signal generation circuits 16, 26, 36 of R, G, B. Reference numeral 43 is a uniformity circuit including R, G and B correction circuits 13, 23 and 33 and a color unevenness / luminance correction waveform signal generation circuit 40.

Next, the operation will be described. It is assumed here that a color unevenness reducing optical system is used as the optical system of the video projector, and the R illuminance distribution on the screen is as shown in FIG. (The illuminance distribution of B is symmetrical to the Y axis of the distribution of R) At this time, the luminance distribution on the screen is as shown in FIG. The video matrix circuit 1 demodulates an input video signal (either composite or Y / C input) into R, G, B primary color signals. When a video signal is input to the video circuit, a synchronization signal (Sync signal) is also input at the same time. The luminance correction waveform signal generation circuit 45 creates a horizontal luminance correction waveform signal (horizontal parabolic signal) and a vertical luminance correction waveform signal (vertical parabolic signal) that are synchronized with the synchronization signal, and multiplies them in the same circuit to obtain a luminance correction waveform. A signal is created. Further, the color nonuniformity correction waveform signal generation circuit 46 creates a horizontal color nonuniformity correction waveform signal (horizontal tertiary waveform) and a vertical color nonuniformity correction waveform signal (vertical parabolic signal), and multiplies these signals to generate R and B colors. A non-uniformity correction waveform signal is created. As a method of generating the correction waveform signal, a convergence correction waveform generation IC is used.

As for R and B, it is necessary to combine the correction waveform signals for both the color unevenness correction and the luminance correction to create the R and B correction waveform signals. Now, color unevenness correction X,
Assuming that the luminance correction is correction Y and the R or B video primary color signal before correction is A, both corrections are performed in order to modulate the video primary color signal, and the correction is performed. It is expressed by the following Equation 1. B = (1 + X) · (1 + Y) A ··· Equation 1 (= A + (X + Y + XY) A) ··· Equation 1 ′

On the other hand, considering that the color nonuniformity correction signal and the luminance correction signal are combined to perform the correction by one modulation (the combined correction signal is Z), the corrected primary color signal C is expressed by the following expression 2
It is represented by. C = ZA ··· Equation 2

Since B and C obtained after the correction must be the same, the equations 1 and 2 must be equal, and for this purpose, the following equation 3 must be established. .. Z = (1 + X) (1 + Y) = 1 + X + Y + XY Formula 3

Therefore, as can be seen from the equation 3, the correction waveform signals of R and B are the sum signal (X +) of the product signal (XY) of the color unevenness correction waveform signal (X) and the luminance correction waveform signal (Y) and both correction waveforms.
It can be seen that this can be obtained by adding Y). Equation 3
The constant 1 on the right side of is considered not to be treated in the corrected waveform signal because it is considered that the original signal which has not been modulated exists in the corrected signal (considered as in Expression 1 ').

The R and B correction waveform signals are obtained by adding the product signal of the color nonuniformity correction waveform signal and the luminance correction waveform signal and the sum signal of both correction waveform signals in the correction waveform signal generating circuits 16 and 36. The brightness correction waveform signal of G is sent to the G correction waveform signal generation circuit 26 as it is. The correction waveform signals of R, G, B created as described above are respectively R, G, B.
Is sent to the correction circuits 13, 23 and 33.

The R, G, and B correction circuits 13, 23, and 33 have exactly the same configuration, and this configuration is shown in FIG. In the figure, 2 is a multiplication circuit for multiplying the correction waveform signal and the primary color signal to create a correction signal, and 4 is an addition circuit for adding the primary color signal and the correction signal. Next, the operation will be described. The corrected primary color signal is the one obtained by modulating the primary color signal with a waveform (X + Y + XY) obtained by adding the product of the color irregularity and the luminance both correction waveforms and the sum of both correction waveforms as shown in Equation 3, and adding the primary color signal. Is. In the multiplication circuit 2, the luminance correction signal is created by multiplying the primary color signal and the luminance correction waveform signal (X + Y + XY). Next, the correction signal and the primary color signal are added by the adder circuit 4 to obtain a corrected primary color signal. Since there is no color unevenness correction signal in G, the luminance correction waveform signal becomes the G correction waveform signal, but the operation is the same as in R and B. (Hereinafter, this primary color signal modulation method is referred to as modulation method 1.) In the modulation method 1, since many primary color signals are included in the output primary color signal, S / N is less damaged.

The correction levels for the color unevenness correction and the brightness correction can be adjusted by controlling the amplitudes of the color unevenness correction waveform signal and the brightness correction waveform signal, respectively, when creating the R and B composite correction waveform signals.

The primary color signals on which the R, G, and B color irregularities and luminance have been corrected as described above are output circuits 12, 2
Sent to 2, 32, amplified here, C of R, G, B
The RT11, 21, 31 is driven to display an image on which color unevenness and brightness correction have been performed on the CRT 11, 21, 31 and is projected on the screen by the projection lens to reduce the color unevenness on the screen. In addition, the brightness of the peripheral portion of the screen is also corrected, resulting in an image with improved uniformity.

Example 2. In the above embodiment, the correction circuits 13, 23, and 33 obtain the corrected primary color signal by adding the correction signal and the primary color signal. However, an addition circuit for adding the primary color signal and the correction signal is used. The primary color signal (1 + X + Y + X) corrected only by the modulation circuit
Y) can be constructed, and such an embodiment will be described here. FIG. 14 shows the configuration of the correction circuits 13, 23, 33 in this embodiment. The other configuration of the uniformity circuit is the circuit configuration described in the first embodiment. In FIG. 14, reference numeral 3 is a multiplication circuit for modulating the primary color signal by multiplying the correction waveform signal and the primary color signal. The correction signal used here is 1 + X + Y + X on the right side of Expression 3.
Corresponding to Y, the correction waveform signal (X + Y +
XY) and the correction waveform signal of this embodiment are the differences between whether the corrected primary color signal is obtained or not only by modulation, and the correction waveform signal has a DC level (whether there is a constant 1 or not). ), The AC components of the correction waveform signal are the same, as can be seen from the equation. Further, the level adjustment for each correction can be performed by controlling the amplitude of the AC component of the correction waveform signal.

The correction circuits 13, 23, 3 shown in this embodiment
In No. 3, since the adder circuit is not required in the correction circuit, there is an advantage that the scale of the uniformity circuit is smaller than that of the uniformity circuit (modulation method 1) shown in the first embodiment. (Hereinafter, this primary color signal modulation method will be referred to as modulation method 2
Say)

Example 3. R, G shown in Examples 1 and 2,
In order to reduce the scale of the correction circuit, the B correction circuits 13, 23, and 33 compose a correction waveform capable of performing both corrections by combining the R and B color unevenness and luminance correction waveform signals. Correction waveform signal creation circuit 1 for R and B correction waveform signals
6 and 36 are required, and the correction waveform signal generation circuit 40 becomes large because the correction waveform signals of R and B are created here. Therefore, on the corrected waveform signal generation circuit 40 side, R,
The circuit may be configured such that the color nonuniformity correction signal and the luminance correction signal are created by the correction circuits 13 and 33 without adding the B composite correction waveform, and these are added to the primary color signal. FIG. 15 is a configuration block diagram of the R and B correction circuits configured as described above.
Shown in. In addition, the correction waveform signal generation circuit 40 uses R, G, B
The correction waveform signal generating circuits 16, 26 and 36 are unnecessary. Since the correction of G is only the brightness correction, the correction circuits shown in the first and second embodiments are used. (Less than,
The method of modulating the R and B primary color signals is referred to as modulation method 3.) The level adjustment for each correction is performed by controlling the amplitude of each correction waveform signal.

Example 4. The R and B correction circuits 13 and 33 shown in the third embodiment use the addition circuit 4 to add the color unevenness correction signal, the brightness correction signal, and the primary color signal created by the color unevenness and brightness correction waveform signals. Although the addition is performed, the correction circuit may be configured without using the addition circuit as in the second embodiment. An embodiment of the correction circuit configured in this way is shown in FIG.
6 shows. Note that the G correction is only brightness correction, so
The correction circuit shown in the first and second embodiments is used. Further, in FIG. 16, the R and B primary color signals are modulated in the order of color unevenness correction and luminance correction, but the order of this modulation may be reversed. (Hereinafter, this method of modulating the R and B primary color signals is referred to as modulation method 4.) However, since the correction amount of the luminance correction amount is larger than the correction amount of the color unevenness, the circuit configuration should be adjusted by the procedure shown in FIG. It is an advantage. The level adjustment for each correction is performed by controlling the amplitude of each correction waveform signal.

As described above, the R and B correction circuits have four methods of modulation methods 1 to 4, and the G correction circuit has two methods of modulation methods 1 and 2. Therefore, there is a demerit that the circuit scale becomes large, but R,
The modulation method using the corrected waveform signals of the G and B primary color signals may be freely selected from the above modulation methods and combined to form a uniformity circuit.

The R, G, B correction circuits 13, 23,
Even if 33 is configured by each of the modulation methods described above, the adjustment method of the correction level can be performed by controlling the amplitude of each correction waveform signal.

Example 5. In each of the above embodiments, the case where the color unevenness correction and the brightness correction are performed by modulating the R, G, B primary color signals has been described. However, as shown in FIG. 2, the color unevenness correction is performed by the R, B primary color signals. And the brightness correction is R,
It may be performed by giving a brightness correction waveform to G1 of the G, B CRTs 11, 21, 31. In FIG. 2, reference numeral 40 denotes a correction waveform signal generation circuit including a luminance correction waveform signal generation circuit 45 and color unevenness correction waveform signal generation circuit 46, and 44 gives a luminance correction waveform signal to G1 of three CRTs 11, 21, and 31. G1 drive circuit for Also, 43 is R, B
Is a uniformity circuit including the correction circuits 13 and 33, the correction waveform signal generation circuit 40, and the G1 drive circuit 44. It should be noted that if the circuit is configured in this way, the G correction circuit 23 for modulating the G primary color signal becomes unnecessary.

Further, the correction circuits 13 and 3 for R and B at this time are also provided.
The circuit configuration of 3 has two types of modulation methods 1 and 2 shown in the first and second embodiments, and either one of them may be used. The correction waveform signal at this time is only the color unevenness correction waveform signal for both R and B, and the correction level is adjusted by controlling the amplitude of each color unevenness correction waveform signal.

On the other hand, R, G, B CRTs 11, 21, 3
The luminance correction waveform (horizontal parabolic waveform × vertical parabolic waveform) given to G1 of 1 is a color unevenness, luminance correction waveform generation circuit 4
0, which is amplified to a voltage required to drive G1 in the G1 drive circuit 44, and three CRTs 11, 2
Given to G1 of 1,31. Since the G1 voltage of the CRT is modulated by the brightness correction waveform signal, the electron beam amount emitted from the electron gun is modulated by the brightness correction waveform signal, and the electron beam amount in the portion where the brightness in the peripheral portion of the screen is reduced increases. , C
As for the raster imaged on the RT fluorescent screen, the brightness-corrected raster image can be obtained. Also, the brightness correction level is adjusted by G
This is performed by controlling the amplitude of the brightness correction waveform signal at the stage of creating the brightness correction voltage given to 1.

By configuring the uniformity circuit 43 as described above, optimal color unevenness correction and brightness correction can be performed independently of color unevenness correction and brightness correction and without interfering with each other. Will be improved.

Example 6. In the embodiment shown in FIG. 3, the correction waveform signals for the color unevenness correction and the brightness correction are C of R, G, and B.
This is a uniformity circuit configured to modulate the beam current by applying it to G1 of RT11, 21, and 31, and to perform color unevenness and brightness correction. In FIG. 3, reference numeral 40 denotes a luminance correction waveform signal generation circuit 45, a color unevenness correction waveform signal generation circuit 46, correction waveform signal generation circuits 16 for R, G and B,
A correction waveform signal generation circuit composed of 26 and 36, 44 a G1 drive circuit for driving G1 of R, G and B CRTs 11, 21 and 31 respectively, and 43 a correction waveform signal generation circuit 40 and the G1 drive circuit It is a uniformity circuit composed of 44. When the uniformity circuit is configured as described above, the correction circuits 13, 23, and 33 that modulate the R, G, and B primary color signals with the correction waveform signals of the respective colors are unnecessary, and the video circuit used in the conventional video projector is eliminated. It can be used as it is.

Three CRTs 11, 21, 3 used here
The correction waveform signal given to G1 of 1 is the same as the waveform described in the first embodiment, and only the amplitude level of the correction signal is different. The color unevenness correction waveform signal includes a horizontal third-order waveform signal and a vertical two-dimensional waveform signal.
The product of the next (parabolic) waveform signal and the brightness correction waveform signal are the product of the horizontal secondary (parabolic) waveform signal and the vertical secondary (parabolic) waveform signal, and R and B are the correction waveforms for both color unevenness and brightness correction. In the combined correction waveform signal G, the luminance correction waveform signal becomes a correction waveform signal, and the above-mentioned correction waveform signal is amplified by the G1 drive circuit 44 and given to G1 of each CRT 11, 21, 31 to perform each correction.

The color unevenness correction amount and the brightness correction amount can be adjusted by controlling the amplitudes of the color unevenness correction waveform signal and the brightness correction waveform signal, respectively.

Example 7. In the embodiment shown in FIG. 4, the brightness correction is performed by modulating the R, G, B primary color signals with the brightness correction waveform signal, and the R, B color unevenness correction is performed by the CRT 1 of the R, B.
This is a uniformity circuit configured to perform correction by applying a color unevenness correction waveform signal to G1 of 1 and 31. In FIG. 4, reference numeral 40 is a correction waveform signal generation circuit including a luminance correction waveform signal generation circuit 45 and a color unevenness correction waveform signal generation circuit 46, and 43 is a correction waveform signal generation circuit 40 and C of R and B.
G11 drive circuit 44 of RT11, 31 and R, G, B
A correction circuit 13 for modulating the primary color signal with the luminance correction waveform signal,
It is a uniformity circuit composed of 23 and 33.

The modulation method of the brightness correction waveform signal is the first embodiment.
There are two modulation methods 1 and 2 described in 2, but either method may be used. Further, the correction level can be adjusted independently by controlling the amplitude of the luminance correction waveform signal and the amplitudes of the R and B color unevenness correction waveform signals.

Example 8. In the embodiment shown in FIG. 5, R,
The uniformity circuit is configured so that the G and B primary color signals are separately modulated by the color unevenness and the luminance correction waveform signal to perform correction. In FIG. 5, reference numeral 40 is a correction waveform signal generation circuit including a luminance correction waveform signal generation circuit 45 and color unevenness correction waveform signal generation circuit 46, and 43 is a correction waveform signal generation circuit 4.
0, R and B correction circuits 13 and 33, and G correction circuit 2
It is a uniformity circuit consisting of three. The R and B correction circuits 13 and 33 are composed of the color unevenness correction circuit 41 and the brightness correction circuit 42 (the order of installing the correction circuits may be other than that shown in FIG. 5), and the G correction. The circuit 23 is composed of a brightness correction circuit 42. At this time, the color nonuniformity correction circuit 41 and the brightness correction circuit 42 have two types of modulation methods 1 and 2, but either method may be used.

When the uniformity circuit is constructed as shown in this embodiment, it is necessary to provide a total of 5CH modulation circuits for R, G, and B, but since these 5CHs can be made to have exactly the same construction, The method of adjusting the correction level and the method of adjusting the circuit are all the same, and the adjuster can easily make the adjustment. The color unevenness and the brightness correction level are adjusted by controlling the color unevenness or the amplitude of the brightness correction waveform signal input to each of the 5CH modulation circuits.

Example 9. In the embodiment shown in FIG. 6, the brightness signal of the video signal (either composite or Y / C input) before being input to the video matrix circuit 1 is modulated by the brightness correction waveform signal, so that R, G, B Luminance correction processing is performed before demodulation into primary color signals, and then the video matrix circuit 1 demodulates into R, G, and B primary color signals, and the R and B primary color signals are modulated by the color unevenness correction waveform signal. It is a uniformity circuit configured to perform unevenness and brightness correction. With the above configuration, since the luminance correction has already been completed when demodulated into the R, G, and B primary color signals, the G primary color signal can be guided to the output stage 22 as it is, and thus the G correction circuit 13 Becomes unnecessary. Note that FIG.
In the figure, 45 is a luminance correction waveform signal generation circuit, 46 is a color unevenness correction waveform signal generation circuit, and 40 is composed of a luminance correction waveform signal generation circuit 45 and a color unevenness correction waveform signal generation circuit 46. Further, 42 is a brightness correction circuit that modulates the video signal before demodulation into R, G, B primary color signals with a brightness correction waveform signal, 43 is a correction waveform signal generation circuit 40 and brightness correction circuit 42, and correction of R, B It is a uniformity circuit including circuits 13 and 33.

When the uniformity circuit is configured as described above, when the video signal is input as a composite signal, the composite signal is Y / C separated and then the Y signal is modulated, while the Y / C signal is input. In this case, by modulating the Y signal as it is, only one set of the modulation circuit for the brightness correction is required, and a total of three sets of the correction circuit for the correction including the R and B color unevenness correction modulation circuits 13 and 33 are sufficient. Therefore, the circuit scale of the uniformity circuit can be reduced. In addition, uneven color,
The adjustment method of the brightness correction level is performed by controlling the color unevenness and the amplitude of the brightness correction waveform signal, as in the above embodiments.

Further, in the embodiment shown in FIG. 6, the method of correcting the R and B color unevenness is used to modulate the R and B primary color signals, but the R and B color unevenness correction is performed by the R and B CRT. It is also possible to perform correction by applying a color unevenness correction waveform signal to G1. In this case, the R and B correction circuits 13 and 33 are unnecessary, and the configuration as shown in the sixth embodiment is obtained. The uniformity circuit 43 is composed of a correction waveform generation circuit 40, a brightness correction circuit 42, and an R, B G1 drive circuit 44, and the same effect as that of the above-described embodiment can be obtained. The method of adjusting the correction level is also the same as that in each of the above embodiments.

Example 10. In the embodiment shown in FIG. 7, the analog video signal that has not been demodulated before being input to the video matrix circuit 1 is digitally converted by the A / D conversion circuit 51, and the digital video signal is converted into R,
Digital R, G, and B that have been subjected to color unevenness and brightness correction by performing demodulation into G and B primary color signals and color unevenness and brightness correction processing.
This is a uniformity circuit configured to correct the color unevenness and the brightness by converting the primary color signal into the analog primary color signal again by the D / A conversion circuit 53. Further, by making software of the digital signal processing circuit 52 capable of processing various image quality adjustments such as bright and contrast by calculation, the video circuit can be fully digitized. In FIG. 7, 51 is an A / D conversion circuit for converting an input analog video signal into a digital video signal, 52 is a video signal processing circuit for performing R, G, B demodulation and color unevenness, brightness correction calculation, and various image quality adjustment calculations, Reference numeral 53 is a D / A conversion circuit for converting an R, G, B digital primary color signal into an analog primary color signal, and 51, 52 and 53 constitute a uniformity circuit 43.

In this embodiment, since the video signal is modulated by the digital arithmetic processing for the color unevenness and the brightness correction,
Although the circuit scale of the video circuit becomes large, not only can color unevenness and brightness be corrected with different correction waveforms for R, G, and B, but R, G, and B of different mass production sets can also be used for the same color.
Even for variations in the illuminance distributions of G and B, each color can be optimally corrected one by one, and the uniformity of the mass production set can be improved. The level of color unevenness and brightness correction can be adjusted by changing the correction coefficient during digital calculation.

Example 11. The above-described first to tenth embodiments have been described as the uniformity circuit in the rear type three-lens type CRT type video projector, but they can also be used in the front type three-lens type CRT type video projector. Front type 3
In the lens type CRT type video projector, residual color unevenness occurs on the screen due to the influence of the projection lens as in the rear type three lens type video projector, and the luminance in the peripheral portion of the screen is lower than the center luminance.
Therefore, by using the uniformity circuit, it is possible to reduce the residual color unevenness and the reduction of the peripheral luminance, and it is possible to improve the uniformity. Also, the method of adjusting the correction level is the same as that of each of the above-described embodiments which are rear type projectors.

Example 12. Among the above embodiments, if the uniformity circuits shown in the embodiments 1 to 4 and 8 to 10 for performing the color unevenness correction and the brightness correction by modulating the R, G, and B primary color signals are used, three lenses using a liquid crystal panel are used. Type liquid crystal video projector, it is possible to improve the residual color unevenness that occurs on the screen due to the influence of the projection lens and the reduction in the luminance of the peripheral portion of the screen, and a three-lens type liquid crystal rear type and a three-lens type liquid crystal front type projector Both sides can improve the uniformity of the image projected on the screen. The configuration of the uniformity circuit 43 is the CR of R, G and B shown in FIGS.
T11, 21, 31 are replaced by R, G, B liquid crystal panels 14, 24, 34, respectively, and output circuits 12, 22, 32 are replaced by liquid crystal panel drive circuits 15, 25, 35, respectively, and other configurations are the same as described above. The configurations shown in the respective drawings showing the embodiments may be maintained.

Example 13. FIG. 8 is a block diagram of an embodiment of a uniformity circuit including a video circuit in a one-lens system liquid crystal projector according to the present invention. In FIG. 8, reference numerals 14, 24, and 34 denote R, G, and B for producing R, G, and B images. B liquid crystal panels 15, 25, and 35 are drive circuits for R, G, and B liquid crystal panels 14, 24, 34, respectively, and correspond to R, G, B output circuits 12, 22, 32 in a CRT projector. Reference numeral 45 is a circuit, and 45 is a luminance correction waveform signal generation circuit. The uniformity circuit 43 is composed of a luminance correction waveform signal generation circuit 45 and correction circuits 13, 23 and 33.

In the one-lens type projector, R,
Before the G and B single-color rasters are combined, a color image is obtained and then the color image is enlarged and projected on the screen. Therefore, since the R, G, and B light sources (liquid crystal panels) are installed on the screen under the same conditions, the uneven illuminance on the R and B screens with respect to the G illuminance due to the influence of the concentration angle does not occur in principle. .. Therefore, color unevenness does not occur. On the other hand, due to the influence of the angle of view of the projection lens, the brightness of the image in the peripheral portion of the screen is reduced. Therefore, in the one-lens system projector, the color nonuniformity correction circuit is unnecessary regardless of the CRT system, the liquid crystal system, and the rear type and the front type projectors, and only the luminance correction is necessary. Therefore, the uniformity circuit of the present invention is composed only of the brightness correction circuit.

From the above, the uniformity circuit of the embodiment shown in FIG. 8 modulates the R, G, B primary color signals with the output correction signal of the luminance correction waveform signal generation circuit 45, and the liquid crystal panel 1
Images are shown on 4, 24 and 34. The R, G, and B modulation circuits 13, 23, and 33 have the two configurations of the above-described modulation methods 1 and 2, but either modulation method may be used. Further, the level adjustment of the brightness correction is performed by controlling the amplitude of the brightness correction waveform signal. As a result, the brightness of the peripheral portion of the screen is corrected, hot spots are eliminated in the central portion of the screen, and the image quality of the projector is improved.

Further, in the embodiment of the present invention shown in FIG. 8, the R, G and B liquid crystal panels 14, 24 and 34 are changed to R,
The CRTs 11, 21 and 31 of G and B, and the liquid crystal panel drive circuits 15, 25 and 35 are connected to the output circuits 12 and 2 for CRT.
FIG. 10 is a block diagram showing the configuration of a video circuit including the uniformity circuit according to the embodiment of the present invention, which is used for a 1-lens type CRT projector by substituting 2 and 32.
Regarding the operation, the R, G, B primary color signals are modulated by the luminance correction waveform signal as in the case of the one-lens type liquid crystal projector. The adjustment method is performed in the same manner as in each of the above-described embodiments, and it is possible to improve the brightness decrease in the peripheral portion of the screen of the image projected on the screen as in the case of the 1-lens type liquid crystal projector, as in the 1-lens type liquid crystal projector. The effect can be obtained.

Example 14 FIG. 9 is a block diagram of another embodiment of the uniformity circuit including the video circuit in the one-lens type liquid crystal projector according to the present invention. In the figure, the uniformity circuit 43 includes a luminance correction waveform signal generation circuit 45 and a video signal (Y It is composed of a brightness correction circuit 42 that modulates a signal). In this example,
The uniformity circuit described in Embodiment 9 is applied to a one-lens system projector. In the uniformity circuit shown in this example, a video signal (composite or Y / C input) before being input to the video matrix circuit 1 may be used. In the composite signal, Y / C separation is performed before luminance correction. ) Luminance signal (Y signal)
Is modulated with a luminance correction waveform signal to perform luminance correction processing before demodulation into R, G, B, and then demodulation into R, G, B primary color signals in the video matrix circuit 1 to obtain an image. It is configured as follows. When the uniformity circuit is configured as described above, the luminance correction process is already completed at the time when the R, G, B primary color signals are demodulated, so that the three primary color signals can be directly guided to the output stage. R, G,
Correction circuits 13, 23, 33 for modulating the B primary color signal
Becomes unnecessary.

When the uniformity circuit is configured as described above, as described in the ninth embodiment, since one set of the brightness correction modulation circuit is required, there is an advantage that the circuit scale of the uniformity circuit becomes small. Further, the adjustment method of the brightness correction level can be performed by controlling the amplitude of the brightness correction waveform signal as in the above-mentioned respective embodiments. Furthermore, the liquid crystal projector using this uniformity circuit can be applied to both rear type and front type projectors.

Further, although FIG. 9 shows an example used in the one-lens system liquid crystal projector, the one-lens system CRT projector also has the liquid crystal panels 14, 24 and 34 in FIG.
To the CRTs 11, 21 and 31 of the R, G and B, and the liquid crystal panel drive circuits 15, 25 and 35 to the CRT output circuits 12, 2
Substituting 2 and 32 can obtain exactly the same effects as the rear type and front type liquid crystal projectors.

Example 15. The embodiment of the uniformity circuit shown in FIG. 11 is an application of the uniformity circuit described in the embodiment 6 to a 1-lens type CRT projector, and this figure is a block diagram of the uniformity circuit including the video circuit in the embodiment. is there. In the figure,
The uniformity circuit 43 is composed of a luminance correction waveform signal generation circuit 45 and a G1 drive circuit 44 of R, G, B CRTs. This uniformity circuit is a correction circuit 1 for modulating the R, G, B primary color signals as described in the sixth embodiment.
3, 23, and 33 are unnecessary, the video circuit used in the conventional projector can be used as it is, and the improvement of the peripheral / center luminance ratio can be achieved in the rear type and front type projectors as in the above embodiments. It

Example 16 Until now, as an element for projecting R, G, B images with a 3 lens or 1 lens system,
The uniformity circuit of a rear type or front type projector using three CRTs or three liquid crystal panels has been described. In addition to these, the projector has one color CRT and one liquid crystal panel. There are also rear type and front type projectors that project an image onto the screen and project the image on a screen with a single projection lens. Even in these projectors, 3CRT, 3
Just like a liquid crystal panel projector, the brightness of the peripheral portion of the screen is reduced due to the influence of the projection lens. However, color unevenness does not occur in principle. Therefore, in these projectors as well, by configuring and using the uniformity circuit of the one-lens system projector described in Embodiments 13 to 15, brightness correction is performed, hot spots disappear on the screen, and the uniformity of the image on the screen is eliminated. A projector is obtained in which improvement can be achieved.

The uniformity circuits of these projectors have the same structure as the R, G, and B liquid crystal panels 14 and 24 shown in FIGS.
It only needs to be replaced with 341 color liquid crystal panels.
On the other hand, in the CRT type projector, the R, G, B CRTs 11, 21, and 31 in FIGS. 10 and 11 may be replaced with one color CRT.

The method of adjusting the brightness correction level can also be performed by controlling the amplitude of the brightness correction waveform signal, as in the above embodiments.

Example 17 In a CRT type projector, there is also a method of applying a luminance correction waveform signal to G1 of a CRT as a method of performing luminance correction, but a 1 CRT projector can similarly configure a uniformity circuit by G1 of a CRT. An embodiment at this time is shown in FIG.
2 shows. In the figure, reference numeral 61 is a CR for showing a color image.
T and 62 are output circuits for R, G and B video signals, and 4
3 is a luminance correction waveform signal generation circuit 45 and a G1 drive circuit 44.
It is a uniformity circuit consisting of. The adjustment method of the brightness correction level can also be performed by controlling the amplitude of the brightness correction waveform signal, as in each of the above embodiments, and the same effect as each of the above embodiments can be obtained.

[0061]

As described above, by using the uniformity circuit of the present invention, it is possible to reduce the amount of residual color unevenness of R and B generated on the screen, and
There is an effect that the rear type and front type video projectors of the three-lens CRT system or the three-lens liquid crystal system capable of improving the center luminance ratio and achieving the uniformity can be obtained. Also, 1-lens CRT system,
Alternatively, in the 1-lens liquid crystal type rear type and front type video projectors, there is an effect that a projector capable of improving the peripheral / center luminance ratio and improving uniformity can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a three-lens type projector according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a three-lens type projector according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a three-lens type projector according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a three-lens type projector according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a three-lens type projector according to a fifth embodiment of the present invention.

FIG. 6 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a three-lens type projector according to a sixth embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a three-lens type projector according to a seventh embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a one-lens type liquid crystal projector according to an eighth embodiment of the present invention.

FIG. 9 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a one-lens type liquid crystal projector according to a ninth embodiment of the present invention.

FIG. 10 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a one-lens CRT projector according to a tenth embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a one-lens CRT projector according to an eleventh embodiment of the present invention.

FIG. 12 is a block diagram showing a configuration of a video circuit including a uniformity circuit for a one-lens CRT projector according to a twelfth embodiment of the present invention.

FIG. 13 is a diagram showing a first example of a configuration of a primary color signal modulation stage of an R, G, B video correction circuit in the present invention.

FIG. 14 is a diagram showing a second example of the configuration of the primary color signal modulation stage of the R, G, B video correction circuit in the present invention.

FIG. 15 is a diagram showing a third example of the configuration of the primary color signal modulation stages of the R and B video correction circuits in the present invention.

FIG. 16 is a diagram showing a fourth example of the configuration of the primary color signal modulation stages of the R and B video correction circuits in the present invention.

FIG. 17 is a block diagram showing the configuration of a video circuit used in a conventional CRT projector without a uniformity circuit.

FIG. 18 shows a G on a screen when a conventional optical system is used in a conventional rear type video projector.
It is a figure which shows the illumination distribution of R normalized to the illumination of.

FIG. 19 is a diagram illustrating an R illuminance distribution normalized to G illuminance on a screen when an optical system that reduces residual color unevenness is used in a conventional rear video projector.

FIG. 20 is a diagram showing a luminance distribution on a screen in a conventional rear type video projector.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 video matrix circuit 2 multiplication circuit (for correction signal generation) 3 multiplication circuit (for primary color signal modulation) 4 addition circuit 11 R-CRT 12 R output circuit 13 R correction circuit 14 R-liquid crystal panel 15 R-liquid crystal panel drive circuit 16 R correction waveform signal generation circuit 21 G-CRT 22 G output circuit 23 G correction circuit 24 G-liquid crystal panel 25 G-liquid crystal panel drive circuit 26 G correction waveform signal generation circuit 31 B-CRT 32 B output circuit 33 B correction circuit 34 B-Liquid crystal panel 35 B-Liquid crystal panel drive circuit 36 B correction waveform signal generation circuit 40 Color unevenness and brightness correction waveform signal generation circuit 41 Color unevenness correction circuit 42 Brightness correction circuit 43 Uniformity circuit 44 G1 drive circuit 45 Brightness correction waveform signal generation Circuit 46 Color unevenness correction waveform signal generation circuit 51 A / D conversion circuit 52 Video signal processing Circuit 53 D / A conversion circuit 61 Color CRT 62 R, G, B output circuit

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[Procedure amendment]

[Submission date] August 5, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Next, the operation will be described. In addition, here, an optical system for reducing unevenness in color is used in the optical system of the video projector to display the illuminance distribution of R on the screen .
It is assumed that it is as shown in 19 . (The illuminance distribution of B is symmetrical to the Y axis of the distribution of R) At this time, the luminance distribution on the screen is as shown in FIG. The video matrix circuit 1 demodulates an input video signal (either composite or Y / C input) into R, G, B primary color signals. When a video signal is input to the video circuit, a synchronization signal (Sync signal) is also input at the same time. The luminance correction waveform signal generation circuit 45 creates a horizontal luminance correction waveform signal (horizontal parabolic signal) and a vertical luminance correction waveform signal (vertical parabolic signal) that are synchronized with the synchronization signal, and multiplies them in the same circuit to obtain a luminance correction waveform. A signal is created. Further, the color nonuniformity correction waveform signal generation circuit 46 creates a horizontal color nonuniformity correction waveform signal (horizontal tertiary waveform) and a vertical color nonuniformity correction waveform signal (vertical parabolic signal), and multiplies these signals to generate R and B colors. A non-uniformity correction waveform signal is created. As a method of generating the correction waveform signal, a convergence correction waveform generation IC is used.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0058

[Correction method] Change

[Correction content]

The uniformity circuits of these projectors have the same structure as the R, G, and B liquid crystal panels 14 and 24 shown in FIGS.
It suffices to replace 34 with a single color liquid crystal panel. On the other hand, the CRT projector is shown in FIGS.
In, the R, G, and B CRTs 11, 21, and 31 may be replaced with one color CRT.

Claims (7)

[Claims] 1. R, G and B three CRTs are respectively provided with R,
G, B monochromatic images are projected, and the images are enlarged and projected on the screen by three projection lenses to obtain color images C
In a video circuit of an RT type rear type video projector or a CRT type front projection type video projector, a color nonuniformity correction waveform signal generating means for R and B primary color signals and a luminance correction waveform signal generating means for R, G and B three primary color signals A means for creating correction waveform signals for each of the three primary colors R, G, B from the output correction waveform signals of the correction waveform generating means; and R, G for output signals of the correction waveform signal creating means.
R, G, B three primary color signals are obtained by adding means for producing video correction signals of G, B primary color signals and addition of output signals of the above R, G, B video correction signal producing means and R, G, B three primary color signals. A uniformity circuit comprising a video circuit having means for correcting the above. 2. R, G and B CRTs each having three R,
G, B monochromatic images are projected, and the images are enlarged and projected on the screen by three projection lenses to obtain color images C
In a video circuit of an RT type rear type video projector or a CRT type front projection type video projector, a color nonuniformity correction waveform signal generating means for R and B primary color signals and a luminance correction waveform signal generating means for R, G and B three primary color signals A means for creating correction waveform signals for each of the three primary colors R, G, B from the output correction waveform signals of the correction waveform generating means; and R, G for output signals of the correction waveform signal creating means.
The video circuit is provided with means for generating G, B correction signals and means for modulating the R, G, B three primary color signals by the output signals of the R, G, B correction signal generating means. Characteristic uniformity circuit. 3. R, G, and B CRTs each having R,
G, B monochromatic images are projected, and the images are enlarged and projected on the screen by three projection lenses to obtain color images C
In a video circuit of an RT type rear type video projector or a CRT type front projection type video projector, a color nonuniformity correction waveform signal generating means for R and B primary color signals and a luminance correction waveform signal generating means for R, G and B three primary color signals And means for modulating the R and B primary color signals with the output signal of the color nonuniformity correction waveform signal generating means, and the R and B color nonuniformity correction modulation with the output signals of the R and B luminance correction waveform signal generating means. A uniformity circuit comprising a means for modulating the output signal of the means and a means for modulating the G primary color signal by the output signal of the G luminance correction waveform signal generating means. 4. R, G, and B CRTs are respectively provided with R,
G, B monochromatic images are projected, and the images are enlarged and projected on the screen by three projection lenses to obtain color images C
In the RT type rear type video projector or the CRT type front projection type video projector, R,
A luminance correction waveform signal generating means for the G, B three primary color signals, and a video circuit having means for modulating each of the R, G, B three primary color signals by an output signal of the luminance correction waveform signal generating means,
Color irregularity correction waveform signal generating means for R and B primary color signals;
A uniformity circuit comprising a G1 drive circuit for supplying the output signal of the luminance correction waveform signal generating means to G1 of two CRTs for B. 5. R, G and B CRTs each having R,
G, B single color image is projected, and the image is enlarged and projected on the screen by three projection lenses to obtain a color image C
In a video circuit of an RT type rear type video projector or a CRT type front projection type video projector, a luminance correction waveform signal generating means for modulating the video signal before demodulation into R, G, B primary color signals, and the above signal. Means for modulating the video signal before demodulation with the output signal of the generating means, and R, G,
A matrix circuit for demodulating to the B primary color signal, color unevenness correction waveform signal generating means for the R and B primary color signals, and means for modulating the R and B primary color signals with the output signal of the color unevenness correction waveform signal generating means are provided. A uniformity circuit characterized by a video circuit. 6. An R, G, B CRT is provided with R,
G, B single color image is projected, and the image is enlarged and projected on the screen by three projection lenses to obtain a color image C
In the video circuit of the RT type rear type video projector or the CRT type front projection type video projector, means for converting the video signal before demodulation into R, G, B primary color signals into digital video signals, and R, G, B primary colors Digital R, G, B arithmetic processing means for performing signal demodulation processing, color irregularity correction processing of R, B primary color signals, and luminance correction signal processing of R, G, B three primary color signals by arithmetic processing of digital video signals. The primary color signals are analog R, G, B
A uniformity circuit comprising a video circuit having means for converting into a primary color signal. 7. A one-lens system 1CRT in which a color image is projected on one color CRT, and the image is enlarged and projected on a screen by one projection lens to obtain a color image.
Method Rear type video projector, 1CRT type front projection type video projector, or 1-lens method to obtain a color image by projecting a color image on a liquid crystal panel and enlarging and projecting the image on the screen with a single projection lens In a video circuit of a liquid crystal type rear type video projector or a front projection type video projector, a luminance correction waveform signal generating means of R, G, B three primary color signals and R, G, B three primary colors by output signals of the correction waveform signal generating means. A uniformity circuit comprising a video circuit having means for modulating a signal.