JPH0856366A - Projection display device and adjusting method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a projection display device in which the characteristics and optical characteristics of a cathode ray tube are automatically adjusted. [Configuration] An adjustment pattern forming circuit controlled by a microcomputer forms an adjustment pattern on a cathode ray tube, and the adjustment pattern projected from the cathode ray tube is detected by a photoelectric conversion element to obtain data and reference data. And a correction voltage is generated to perform cutoff adjustment. [Effect] The characteristics of the cathode ray tube and the optical characteristics can be automatically adjusted, and the adjustment can be performed without being influenced by environmental conditions or changes with time.

Description

Detailed Description of the Invention

[0001]

This invention relates to a cathode ray tube (hereinafter referred to as C
Abbreviated as RT. The present invention relates to a projection type display device for enlarging and projecting the image light from (1) on a screen through a projection lens and a reflection mirror, and an adjusting method thereof, and more particularly to automation of adjustment of characteristics and optical characteristics peculiar to a CRT.

[0002]

2. Description of the Related Art Adjustment items based on the characteristics and optical characteristics of a CRT used in a projection display device include a cutoff adjustment for adjusting a cutoff voltage when a bright spot starts to shine, and a white color for adjusting a white color temperature. Balance adjustment,
The uniformity adjustment for adjusting the white color unevenness may be mentioned. FIG. 21 is a schematic sectional view showing a conventional projection display device, in which 1 is a CRT and 2 is a CRT.
1 is a projection lens arranged in front of the CRT 1 to magnify and project the image light from the CRT 1, 3 is a reflection mirror arranged in front of the projection lens 2, 4 is a screen for forming the image light reflected from the reflection mirror 3, Reference numeral 5 denotes projection light projected from the CRT 1. The auxiliary codes a, b, and c are three CRTs (red R
ED, green GREEN, and blue BLUE) are used, so that they correspond to RED, GREEN, and BLUE CRTs, respectively.

In such a conventional projection display device, the image light from each CRT 1a, 1b, 1c is enlarged and projected by each projection lens 2a, 2b, 2c, and the reflection mirror 3 is projected.
The image is displayed on the screen 4 by being projected onto the screen 4 via. Further, in the conventional projection display device, each CRT is provided with a variable resistor (not shown) for adjusting the cutoff characteristic, the white balance characteristic, and the uniformity characteristic. During cutoff adjustment, the screen 4 is removed, the adjustment jig is used to turn the video signal into a black color, and the cutoff voltage when the bright spot starts to shine while looking into the tube surface of the CRT 1 is manually adjusted with a variable resistor. To do.

Further, when adjusting the white balance, a video signal of a single color (for example, a wind pattern) is input,
An adjustment jig (a photodetector such as a color analyzer) is placed on the center of the front surface of the screen 4, and the variable resistor is manually adjusted so that its output value becomes appropriate. Further, even at the time of adjusting the uniformity, an image signal of a single white color is input, and an adjustment jig (a photodetector such as a color analyzer) is attached to a specific position on the front surface of the screen 4 (upper, lower, left part of the screen 4,
The variable resistor is manually adjusted so that the output value at all positions is equal to the output value at the time of white balance adjustment (the value at the center of the front surface of the screen 4) at several places (right part, etc.).

[0005]

In the conventional projection display device as described above, the screen 4 is used when the cutoff is adjusted.
It is necessary to remove the CRT, and three CRTs
Since the cutoff voltage of 1 had to be adjusted, the adjustment took a lot of time and effort. In addition, the CRT1 can be adjusted only in the manufacturing process of the projection display device, even if it is adjusted once.
Due to various conditions such as deterioration of the phosphor and temperature characteristics of parts, there is a problem that adjustment is required even after manufacturing. Also, when adjusting white balance characteristics and uniformity characteristics, adjustment jigs (light detectors such as color analyzers)
Is required, and a signal of a single white color (such as a window pattern) has to be input, and there is a problem similar to the above, which requires the skill of an operator. Also, 3
Since the emission characteristics of the phosphors of the CRT of the book are different, even if the white balance characteristic and the uniformity characteristic are adjusted at a certain brightness level, the characteristics change depending on the brightness level. When the brightness is other than the brightness level at time, problems such as coloring occur. The present invention has been made to solve the above problems, and an object of the present invention is to obtain a projection display device capable of significantly shortening the adjustment time and easily and automatically adjusting the finished product after manufacturing. And It is another object of the present invention to provide a projection display device capable of obtaining good image quality and automatically adjusting by keeping the white balance characteristic and the uniformity characteristic constant at all luminance levels.

[0006]

A projection display device according to the present invention includes a cathode ray tube, a projection lens for enlarging and projecting an image of the cathode ray tube, and a reflection mirror for reflecting an image for enlarging and projecting by the projection lens. A screen on which an image reflected from the reflection mirror is formed, an adjustment pattern forming circuit for forming an adjustment pattern on the cathode ray tube, and an adjustment pattern formed on the cathode ray tube by the adjustment pattern forming circuit and projected. A photoelectric conversion element for detecting a pattern and an adjustment circuit for adjusting the characteristics of the cathode ray tube by comparing the data detected by the photoelectric conversion element with the reference data are provided.

Further, three cathode ray tubes for displaying red, green, and blue images respectively, three projection lenses for enlarging and projecting the images of these three cathode ray tubes, and an image for enlarging and projecting by each of these projection lenses are displayed. A reflecting mirror that reflects light, a screen on which an image reflected from the reflecting mirror is formed, an adjustment pattern forming circuit that forms adjustment patterns for each of the three cathode ray tubes, and an adjustment pattern forming circuit. By comparing the data detected by this photoelectric conversion element and the reference data with the photoelectric conversion element formed on the three cathode ray tubes and detecting the projected adjustment pattern,
It is equipped with an adjusting circuit for adjusting the characteristics of the two cathode ray tubes. Further, the adjustment pattern forming circuit forms a cut-off adjustment pattern, detects this cut-off adjustment pattern with the photoelectric conversion element, compares the detected data of the photoelectric conversion element with the reference data, and corrects it. A correction voltage generation circuit that generates a voltage is provided, and the adjustment circuit adjusts the cutoff voltage in response to the correction voltage from the correction voltage generation circuit.

Further, the adjusting circuit has a correction amount calculating circuit for comparing the data detected by the photoelectric conversion element with the reference data and calculating the correction amount, and receives the correction amount from the correction amount calculating circuit for adjustment. It is a thing. Furthermore, the adjustment pattern is a white balance adjustment pattern, and the adjustment circuit adjusts the white balance. Also, the adjustment pattern is a uniformity adjustment pattern,
The adjustment circuit adjusts the uniformity. Further, the adjusting circuit is a luminance / chromaticity measuring circuit for measuring the luminance and chromaticity of the data detected by the photoelectric conversion element, and the luminance / chromaticity measuring circuit.
The luminance and chromaticity measured by the chromaticity measurement circuit are compared with reference data, and the difference between the adjustment target value error calculation circuit that calculates the difference and the error calculated by this adjustment target value error calculation circuit is corrected. An amplitude conversion control unit that performs amplitude conversion of the adjustment pattern based on the correction amount calculated by the correction amount calculation circuit is provided. Further, the adjusting circuit adjusts the brightness of the adjusting pattern formed by the adjusting pattern forming circuit so as not to change.

In addition, the adjustment pattern forming circuit is controlled by a microcomputer and can sequentially change the amplitude of the adjustment pattern signal from a low level to a peak level. The adjustment pattern forming circuit is controlled by a microcomputer and sequentially changes the amount of change and the speed of change in the amplitude of the adjustment pattern signal at time intervals that can be detected by the photoelectric conversion element. Further, the adjustment pattern is a white balance adjustment pattern, and the adjustment circuit adjusts the gradation characteristic of white balance. Also, the adjustment pattern is a uniformity adjustment pattern, and the adjustment circuit
It is intended to adjust the gradation characteristics of uniformity. Furthermore, the adjustment pattern forming circuit is controlled by a microcomputer and causes the adjustment pattern to be sequentially interrupted in a certain frame of the video signal of the cathode ray tube at a predetermined time interval.

Further, the adjustment pattern forming circuit is controlled by a microcomputer and controls the adjustment pattern to a size not more than a predetermined size and not less than a size detectable by the photoelectric conversion element. The reference data is read from the memory by the microcomputer. In addition, the photoelectric conversion element is provided on the panel arranged in front of the screen. Also, on the reflection mirror, only at the position where the adjustment pattern is projected,
A hole for transmitting the projection light to the rear surface of the mirror is provided, and the photoelectric conversion element is arranged at a position facing the hole.
Furthermore, the angle between the center line of the photoelectric conversion element and the rear surface of the reflection mirror is equal to the incident angle of the projected light, and the distance between the light detection part of the photoelectric conversion element and the center of the hole is affected by light other than the light to be measured. It is a distance that is not affected. Further, a concave lens is arranged in front of the photoelectric conversion element on the rear surface of the reflection mirror.

In the method of adjusting the projection display device according to the present invention, the projection lens is arranged in front of the cathode ray tube, and the image enlarged and projected by the projection lens is reflected by the reflection mirror to be formed on the screen. In the method for adjusting a projection display device configured to perform, a panel having a photoelectric conversion element is arranged on the front surface of the screen, and the adjustment pattern formed on the cathode ray tube is detected by the photoelectric conversion element. And the reference data are compared to adjust the characteristics of the cathode ray tube.
Further, a panel having a photoelectric conversion element is arranged on the front surface of the screen, and the characteristics of the cathode ray tube in the manufacturing process are adjusted by using the data detected by the photoelectric conversion element. Furthermore, the photoelectric conversion element arranged on the panel and the photoelectric conversion element on the rear surface of the reflection mirror are arranged so as to correspond to each other so as to detect the same adjustment pattern.
Further, the number of photoelectric conversion elements arranged on the panel does not exceed the number of photoelectric conversion elements on the rear surface of the reflection mirror. Further, when the characteristics of the cathode ray tube are adjusted in the manufacturing process, the data detected by the photoelectric conversion element on the rear surface of the reflecting mirror is stored in the memory as reference data. Further, the adjustment pattern is such that the amplitude of the signal is sequentially changed from the low level to the peak level. Further, the adjustment pattern is formed with a predetermined size or less and a size that can be detected by the photoelectric conversion element or more.

[0012]

In the projection type display device having the above-mentioned structure, the adjustment pattern formed by the adjustment pattern forming circuit is detected by the photoelectric conversion element, and the detected data is compared with the reference data to determine the deviation amount. Adjust the characteristics of the cathode ray tube so that Further, by the adjustment pattern forming circuit forming the cutoff adjustment pattern,
This cut-off adjustment pattern is detected by a photoelectric conversion element, and the detected data and reference data are compared,
Adjust the cutoff so that the amount of deviation is minimized. Also,
The adjustment circuit has a correction amount calculation circuit that compares the data detected by the photoelectric conversion element with the reference data and calculates the correction amount,
The correction amount is received from the correction amount calculation circuit and adjusted so as to minimize the shift amount. Furthermore, the adjustment circuit adjusts the white balance by using the white balance adjustment pattern as the adjustment pattern.

Further, the adjustment circuit adjusts the uniformity by using the uniformity adjustment pattern as the adjustment pattern. Further, the adjusting circuit compares the luminance and chromaticity measuring circuit for measuring the luminance and chromaticity of the data detected by the photoelectric conversion element with the luminance and chromaticity measured by the luminance and chromaticity measuring circuit with reference data, In order to correct the error calculated by the adjustment target value error calculation circuit for calculating the difference and the adjustment target value error calculation circuit, the amplitude of the adjustment pattern is calculated based on the correction amount calculated by the correction amount calculation circuit from this error. An amplitude conversion control unit that performs conversion is provided, and adjustment is performed by amplitude conversion based on the correction amount. In addition, the adjustment pattern forming circuit is controlled by the microcomputer, and sequentially adjusts the amplitude of the adjustment pattern signal from a low level to a peak level, thereby performing adjustment at each amplitude.
Further, by forming the adjustment pattern by the microcomputer, it is possible to sequentially change the change amount and the change speed of the amplitude of the adjustment pattern signal at time intervals that can be detected by the photoelectric conversion element. Further, the white balance adjusting pattern is used as the adjusting pattern, and the adjusting circuit adjusts the gradation characteristic of the white balance. Further, the adjustment circuit adjusts the gradation characteristic of uniformity by using the uniformity adjustment pattern as the adjustment pattern.

Further, by forming the adjustment pattern by the microcomputer, the adjustment pattern can be sequentially interrupted in the frame at predetermined time intervals. Further, the adjustment pattern is formed by the microcomputer so that the adjustment pattern has a predetermined size or smaller and a size that can be detected by the photoelectric conversion element or larger, so that the ACL does not get caught. In addition, the photoelectric conversion element is provided on the panel arranged in front of the screen, and adjustment in the manufacturing process is performed based on the data detected by the photoelectric conversion element.

Further, a photoelectric conversion element is provided only at a specific position on the rear surface of the reflecting mirror to reduce the amount of projection light transmitted. Furthermore, the angle between the center line of the photoelectric conversion element on the rear surface of the reflection mirror and the rear surface of the reflection mirror is made equal to the incident angle of the projection light, the projection light is detected efficiently, and the light detection section of the photoelectric conversion element and the reflection mirror are By controlling the distance from the center of the hole,
It was set so as not to be affected by light other than the light to be measured.

Further, a concave lens is arranged in front of the photoelectric conversion element on the rear surface of the reflecting mirror to improve the directivity of the projection light,
It is designed so that it is not affected by light other than the light that is detected and measured efficiently. Further, a panel having a photoelectric conversion element is arranged on the front surface of the screen, and the adjustment in the manufacturing process is performed based on the data detected by the photoelectric conversion element so as to minimize the shift amount. Further, the same adjustment pattern is detected by making the photoelectric conversion element on the rear surface of the reflection mirror correspond to the photoelectric conversion element of the panel. Further, since the data of the photoelectric conversion element on the rear surface of the reflection mirror obtained as a result of the adjustment in the manufacturing process is stored in the memory as the reference data, it can be easily stored. Further, the adjustment pattern is such that the amplitude of the signal is sequentially changed from the low level to the peak level. In addition, the adjustment pattern is formed in a size smaller than a predetermined size and larger than a size detectable by the photoelectric conversion element, and the ACL (AUTOMATIC CURRENNT LIMIT) is formed.
TER).

[0017]

【Example】

Example 1. 1 is a schematic sectional view showing a projection display apparatus according to Embodiment 1 of the present invention, FIG. 2 is a schematic sectional view showing a reflection mirror in FIG. 1, and FIG. 3 is a position of a reflection mirror and a photoelectric conversion element in FIG. FIG. 4 is a diagram showing a relationship, FIG. 4 is an adjustment pattern forming circuit of the projection display apparatus according to Embodiment 1 of the present invention, and FIG. 5 is a reflection mirror seen from the projection side when a cutoff adjustment pattern is projected. 6 is a diagram showing a feedback system of the projection display apparatus according to Embodiment 1 of the present invention, and FIG. 7 is a flowchart showing cutoff adjustment using the microcomputer according to Embodiment 1 of the present invention. In the figure, 1 to 5 are the same as the above-mentioned conventional device, and the description thereof is omitted. 6 is a panel arranged on the front surface of the screen, 7 is a photoelectric conversion element such as a CCD installed on the rear surface of the reflection mirror 3, 8 is a photoelectric conversion element installed on the panel 6, and is located at a position corresponding to the photoelectric conversion element 7. It is provided. 9 is glass, 10 is an aluminum film, and glass 9
Together with this, the reflection mirror 3 is configured. 11 is an aluminum film 1
A hole opened at 0 and a light detection portion 12 of the photoelectric conversion element 7. It should be noted that m is the width of the hole 11, θ is the angle formed by the aluminum film 10 and the center line of the photoelectric conversion element 7, and n is the distance between the photodetector 12 and the center of the hole 11.

Reference numeral 13 is an adjustment pattern forming circuit.
14 is a field determination circuit, 15 is a V counter, 16
Is an H counter, 17 is a character coordinator, 18 is a black level detection circuit, 19 is a switch, and these constitute an adjustment pattern forming circuit 13. 20 is a microcomputer. Reference numeral 21 denotes a cut-off adjustment pattern projected on the front surface of the reflection mirror 3, and the photoelectric conversion element 7 is installed on the rear surface of the reflection mirror 3 corresponding to this position. Reference numeral 22 is a memory such as an EEPROM for storing reference data, 23 is a correction voltage generating circuit for comparing the data stored in the memory 22 with the data from the photoelectric conversion element 7, and correcting the error amount, 24 is a correction voltage It is a cutoff adjustment circuit that adjusts the cutoff voltage based on the output from the generation circuit 23. The broken line indicates the microcomputer 20.
The control signal from is shown.

In the projection type display device having such a configuration, the image formed on the CRT 1 is enlarged and projected by the projection lens 2 and becomes the projection light 5 which is projected on the screen through the reflection mirror 3 for viewing. Be used for. Here, since the projection light 5 projected on the front surface of the glass 9 of the reflection mirror 3 has a different refractive index inside the glass 9, it is refracted and proceeds as shown in FIG. It is reflected at 10 and projected on the screen 4. Projection light 5
Is focused on the screen 4, so that the reflecting surface of the reflecting mirror 3 is not focused as shown in FIG. 2 and has a certain width. Therefore, if a hole 11 is formed with a width m in a part of the aluminum film 10 where the projection light 5 having this width is projected, the projection light 5 projected onto this part is reflected. Without passing through the rear surface of the mirror.
By installing the photoelectric conversion element 7 in this portion, the brightness and color of the projection light 5 are detected. In addition, the amount of transmitted light can be changed by changing the width m of the hole 11. The width m is such that it does not affect the projected image on the screen 4 and that the photoelectric conversion element 7 can detect light.

The angle θ formed between the rear surface of the reflecting mirror 3 and the center line of the photoelectric conversion element 7 shown in FIG. 3 is such that the incident light of the projection light 5 is detected in order to efficiently detect the light transmitted to the rear surface of the mirror. Is set to be equal to. In addition, the hole 1 formed in the aluminum film 10 so as not to be influenced by unnecessary light other than the measured light among the light transmitted to the rear surface of the mirror 1.
An appropriate distance n is provided between the center of 1 and the photodetector 12 of the photoelectric conversion element 7.

The adjustment pattern forming circuit 13 shown in FIG.
The microcomputer 20 issues an adjustment pattern output command, and in response to this, the field determination circuit 14 determines whether the current image is the first field or the second field. , 15
Corresponding to the number of counts, the adjustment patterns for the photoelectric conversion elements 7 are sequentially installed at the locations where the photoelectric conversion elements 7 are installed.
Interrupt by 9. The time and interval at which the adjustment pattern is interrupted are such that the adjustment pattern is actually invisible to human eyes on the screen 4 and can be detected by the photoelectric conversion element 7. Controlled by. FIG. 5 shows the reflection mirror 3 seen from the projection side when the cut-off adjustment pattern 21 is projected by the adjustment pattern forming circuit 13 on the central portion of the projected image, and the cut projected on the front surface of the reflection mirror 3 is shown. The reflection mirror 3 corresponding to the off adjustment pattern 21
It shows that the photoelectric conversion element 7 is installed on the rear surface.

Next, the cutoff adjustment in the manufacturing process will be described with reference to FIGS. 6 and 7. When the cut-off adjustment pattern 21 is output from the adjustment pattern forming circuit 13 in response to a command from the microcomputer 20, this output is formed as an image on the CRT 1, is enlarged and projected by the projection lens 2, and is transmitted through the reflection mirror 3. Is projected on the screen 4. The brightness of the projected light is detected by the photoelectric conversion element 8 installed on the panel 6. The correction voltage generating circuit 23 compares the data obtained by the detection with the reference data used in the manufacturing process, and changes the cutoff correction voltage so that the cutoff becomes appropriate. Based on this output, the cutoff adjustment circuit 24 adjusts the cutoff. The detection of the projection light by the photoelectric conversion element 8, the variation of the cutoff correction voltage, and the cutoff adjustment are repeated until the cutoff becomes appropriate, and when the cutoff becomes appropriate, the photoelectric conversion element of the reflection mirror 3 The data No. 7 is stored in the memory 22 as reference data used after the completion of the device. The above process is performed in the manufacturing process of the device, and the cutoff is automatically adjusted. After the device is completed, the microcomputer 20 automatically outputs the cutoff adjustment pattern 21 as shown in FIGS. 6 and 7, and the data from the photoelectric conversion element 7 of the reflection mirror 3 at that time is cutoff in the manufacturing process. The cutoff adjustment is automatically performed so as to be equal to the reference data on the memory 22 obtained as a result of the adjustment.

Example 2. In the first embodiment, the number of cutoff adjustment patterns is set to one, but a plurality of cutoff adjustment patterns are used in the first embodiment.
The same effect as can be obtained.

Example 3. Although the number of cut-off adjustment patterns and the number of photoelectric conversion elements are the same in the first embodiment, the same effect as that of the first embodiment can be obtained even if the number of photoelectric conversion elements is reduced. FIG. 8 shows the relationship between the cutoff adjustment pattern and the photoelectric conversion element.
× 4 In the case of forming a total of 12 photoelectric conversion elements 7 at all positions (12) where the cutoff adjustment pattern 21 is formed.
Or 8 may be omitted, and adjustment may be performed only with the six photoelectric conversion elements 7 or 8.

Example 4. In Example 1, the photoelectric conversion element 7,
Although the cut-off adjustment pattern 21 is projected only on the portion where the photoelectric conversion elements 7 and 8 are installed, for example, the cut-off adjustment pattern 21 is projected on the entire screen, as shown in FIG. Even if 21 is projected, the same effect as that of the first embodiment can be obtained.

Example 5. In the first embodiment, an angle θ is provided between the reflection mirror 3 and the photoelectric conversion element 7 or a distance n is provided so that the transmitted light is efficiently received, and the influence of unnecessary light is not exerted. However, even if a concave lens or the like is installed in front of the photoelectric conversion element 7 to improve directivity, the same effect as that of the first embodiment can be obtained.

Example 6. FIG. 10 is a schematic cross-sectional view showing a projection type display device according to Embodiment 6 of the present invention when three CRTs are used, and FIG. 11 is projection projected on a reflection mirror when three CRTs are used. It is a figure which shows light. In the figure, 1a, 1b, 1c to 5 are the same as the above-mentioned conventional device, and the description thereof is omitted. 6 is the same panel as the first embodiment installed on the front surface of the screen 4, 7a,
Reference numerals 7b and 7c are photoelectric conversion elements similar to those of the first embodiment, provided on the rear surface of the reflection mirror 3 for detecting the projection light from the CRTs 1a, 1b, and 1c, and 8 is the same as the first embodiment installed on the panel 6. With the same photoelectric conversion element, the photoelectric conversion element 7
It is provided at a position corresponding to the position where a, 7b, and 7c are installed.

In the projection type display device having the above-described structure, for example, a red image formed on the CRT 1a is enlarged and projected by the projection lens 2a to become the projection light 5 and the screen through the reflection mirror 3. 4 is projected. The same applies to the projection lights 5b and 5c from the CRTs 1b and 1c, and a color image can be obtained on the screen 4. FIG. 11 shows a CRT on the reflection mirror 3.
Projection lights 5a, 5b, 5 projected from 1a, 1b, 1c
c is shown. The image light projected from the same one point on the CRTs 1a, 1b, 1c is projected on the same one point on the screen 4, so that as shown in FIG. Is projected in the same way. Therefore, the respective projection lights 5a, 5
The photoelectric conversion elements 7a, 7b, 7 for detecting the respective projection lights on the rear surface of the reflection mirror 3 at the positions where b, 5c are projected.
c is installed, and one photoelectric conversion element 8 is installed on the panel 6 corresponding to the three photoelectric conversion elements.

The feedback system for the cut-off adjustment of the projection type display apparatus having the above-mentioned configuration is substantially the same as that shown in FIG. 6, and in FIG. 6, CRTs 1a, 1b, 1c, projection lenses 2a, 2b, 2c, photoelectric conversions are provided. Elements 7a, 7b, 7
c is representatively shown by CRT 1, projection lens 2 and photoelectric conversion element 7, respectively, and the correction voltage generating circuit 23 is CRT 1a,
A correction adjustment voltage is output for each of 1b and 1c. The three-tube cutoff adjustment is individually performed by the cutoff adjustment circuit 24 for each of the CRTs 1a, 1b, 1c, and the operation thereof is obvious from the description of the first embodiment, and will be omitted.

Example 7. Next, an embodiment in which the white balance adjustment can be automated with a three-tube system will be described. 12
FIG. 13 is a diagram showing a feedback system of the projection display apparatus according to the embodiment, and FIG. 13 is a chromaticity diagram (showing a black body locus) of the International Commission on Illumination (CIE). Since the outline of the other devices is the same as that shown in FIGS. 10 and 11, this figure is incorporated. In the figure, 25 is a white balance adjusting circuit. CRT1a, 1b, 1c,
The adjustment pattern forming circuit 13 forms single-color white balance adjustment patterns for red, green, and blue, respectively, and projects them simultaneously onto the respective photoelectric conversion elements 7a, 7b, 7c. The respective projection lights 5a, 5b and 5c are on the screen 4
The brightness and color of the combined projection light combined above
Detected by the photoelectric conversion element 8 on the panel 6 installed on the front of the screen 4, the white balance adjustment voltage is changed and input to each CRT 1a, 1b, 1c so as to obtain an appropriate white based on the data. The gain of the video signal is automatically adjusted, and the data of the photoelectric conversion elements 7a, 7b, 7c when the white color becomes appropriate is stored in the memory 22 as reference data used after the completion of the device.

The above process is performed in the manufacturing process of the apparatus, and the white balance is automatically adjusted. After the device is completed, the adjustment pattern is automatically output by the microcomputer 20, and the white balance adjustment is automatically performed so that the data from the photoelectric conversion elements 7a, 7b, 7c at that time becomes equal to the reference data on the memory 22. Done. here,
The reference data used in the manufacturing process and the reference data after the device is completed will be mentioned. Reference data used in the manufacturing process is stored in advance in the memory 22 such as an EEPROM. However, this reference data and the reference data extracted from the photoelectric conversion element 7 of the reflection mirror 3 have different properties, and there is only one reference data used in the manufacturing process, and the reference data is extracted from the photoelectric conversion element 7 of the reflection mirror 3. The reference data has the same number of data as the number of photoelectric conversion elements. Further, the reference data extracted from the photoelectric conversion element 7 of the reflection mirror 3 takes into consideration the characteristics and optical characteristics of the CRT 1. For example, a color temperature of 10000 ° K on the panel 6
To obtain the white color of (Kelvin), C in FIG.
Based on the chromaticity diagram of IE, reference data of x = 0.28 and y = 0.29 is stored in advance, and all the photoelectric conversion elements 8 on the panel 6 are adjusted to show these values.
The data of the photoelectric conversion element 7 of the reflection mirror 3 at that time is CR.
Since T and optical characteristics are included, data is generally different for each photoelectric conversion element, and this is stored as reference data.

Example 8. Next, an embodiment in which the uniformity adjustment can be automated will be described. In Example 7, white balance adjustment patterns are projected at a plurality of different positions, and the photoelectric conversion element 7 is projected at each of the projected positions.
8 is installed to detect the brightness and color of the projection light 5. As in the case of Example 7, the adjustment voltage fluctuates so that the data of all photoelectric conversion elements 8 installed on the panel 6 has an appropriate white value, and the data of the photoelectric conversion elements 7 on the rear surface of the mirror at that time is changed. Are stored in the memory 22 as reference data used after the completion of the device. As described above, the uniformity is automatically adjusted in the manufacturing process of the device, and the uniformity is automatically adjusted after the device is completed as in the seventh embodiment.

Example 9. Example 9 shows another example of white balance adjustment. FIG. 14 is a schematic sectional view showing a projection type display apparatus according to Embodiment 9 of the present invention. In the figure, 1 to 8 are the same as those in FIG. 1, and their explanations are omitted. FIG. 15 is a diagram showing an adjustment pattern forming circuit of a projection display apparatus according to Embodiment 9 of the present invention. In the figure, 30 is an adjustment pattern forming circuit, 31 is an H counter, 32 is a V counter, 33 is a character generator, and 34 is a switch, and these constitute the adjustment pattern forming circuit 30. Reference numeral 35 is a microcomputer. FIG. 16 is a diagram showing a relationship between the photoelectric conversion element and the adjustment pattern projected on the panel arranged on the front surface of the screen when the white balance adjustment pattern is projected, and in the figure, Reference numeral 36 denotes a white balance adjustment pattern projected on the panel 6, and the photoelectric conversion element 8 is installed on the projection side of the panel 6 corresponding to this position.

FIG. 17 is a diagram showing an input / output characteristic control circuit of a projection display apparatus according to Embodiment 9 of the present invention. In the figure, 37 is an input / output characteristic control circuit. 38 is a luminance / chromaticity measuring circuit for measuring the luminance and chromaticity from the data detected by the photoelectric conversion element 8, 39 is the luminance / chromaticity measuring circuit 3
8 is an adjustment target value error calculation circuit that compares the luminance and chromaticity measured in 8 with reference data and calculates the error,
A correction amount calculation circuit for calculating a correction amount for correcting the error value calculated by the adjustment target value error calculation circuit 39 with reference to the luminance data measured by the chromaticity measurement circuit 38. These are input / output characteristic control circuits. Make up 37. FIG. 18 is a diagram showing a feedback system of the projection type display apparatus according to the ninth embodiment of the present invention. In the figure, 41 is a white balance adjustment circuit, 42 is a memory such as an EEPROM for storing data, 43 is an A / D conversion circuit, 44 is an input / output characteristic output from the input / output characteristic control circuit 37, and 45 is a D / A. A conversion circuit, 46 is an A / D conversion circuit 43, input / output characteristics 44, D /
The amplitude conversion control circuit includes an A conversion circuit 45 and performs amplitude conversion of each color signal of the adjustment pattern based on the correction amount calculated by the correction amount calculation circuit 40. The broken line indicates the control signal from the microcomputer 35.

FIG. 19 is a flow chart showing white balance adjustment using a microcomputer according to the ninth embodiment of the present invention. When the conclusion is written first, the curve approaches the black body locus curve shown in FIG. 13, and the white balance at all luminance levels becomes appropriate as described in the lower part of 19. That is, the configuration of FIG. 18 operates so that the white balance is properly maintained even if the brightness level of the video signal changes. In the projection display device having such a configuration, the images formed on the CRTs 1a, 1b, and 1c are enlarged and projected by the projection lenses 2a, 2b, and 2c to become the projection lights 5a, 5b, and 5c, and the reflection mirror 3 is formed. It is projected on the screen 4 via the and is provided for viewing. In the adjustment pattern forming circuit 30 shown in FIG. 15, the microcomputer 35 issues an adjustment pattern output command, and in response to this, on the panel 6 corresponding to the count numbers of the H-counter 31 and the V-counter 32. Each adjustment pattern is formed in the place where the photoelectric conversion element 8 provided in the above is installed. Further, the amplitude (luminance) of this adjustment pattern can be varied from a low level to a beak level, and its amplitude variation amount and change rate are at a certain time interval that the photoelectric conversion element 8 can detect and at a certain fixed level. It is controlled by the microcomputer 35 so as to keep the adjustment accuracy and reduce the adjustment time as much as possible. The size of the adjustment pattern is also controlled by the microcomputer 35 so that the ACL (auto, contrast, limiter) does not operate. 16
The panel 6 viewed from the projection side when the white balance adjustment pattern 36 is projected on the central portion of the projected image by the adjustment pattern forming circuit 30 is shown, and corresponding to the white balance adjustment pattern 36, It shows that the photoelectric conversion element 8 is installed.

Next, white balance adjustment will be described with reference to FIGS. 17, 18 and 19. In response to a command from the microcomputer 35, the white balance adjustment pattern 36 is output from the adjustment pattern forming circuit 30.
Is output, this output is output to CRTs 1a, 1b, 1c.
Projection lenses 2a, 2b, 2c formed as an image on top
Is magnified and projected on the screen 4 via the reflection mirror 3.
Projected on. The projected light is detected by the photoelectric conversion element 8 installed on the panel 6. Based on the data obtained by the detection, the input / output characteristic control circuit 37 measures the luminance and chromaticity of the white balance adjustment pattern 36, compares the data with the adjustment target value (reference data), The input / output characteristic 44 is changed so that the white balance characteristic becomes appropriate. The white balance is adjusted by the white balance adjusting circuit 41 based on this output. Then, until the white balance becomes appropriate, the projection light is detected by the photoelectric conversion element 8, the input / output characteristic 44 is changed,
The white balance adjustment is repeated, and when the white balance becomes appropriate, the data of the input / output characteristic 44 is stored in the memory 42. The above process is performed in the manufacturing process of the device, and the white balance is automatically adjusted. The white balance adjustment after the device is completed is performed using the photoelectric conversion element 7 as in the seventh embodiment.

Example 10. In the ninth embodiment, the number of white balance adjustment patterns 36 is one, but the same effect as that of the ninth embodiment can be obtained even if a plurality of white balance adjustment patterns 36 are used. Example 11. Next, an embodiment in which the adjustment of the gradation characteristic of white balance can be automated will be described with reference to FIGS. 17, 18 and 19. Similarly to the white balance adjustment of the ninth embodiment, when the adjustment pattern forming circuit 30 outputs the white balance adjustment pattern 36 in response to a command from the microcomputer 35, this output is C
An image is formed on the RTs 1a, 1b, 1c, enlarged and projected by the projection lenses 2a, 2b, 2c, and projected on the screen 4 via the reflection mirror 3. The projected light is detected by the photoelectric conversion element 8 installed on the panel 6. Based on the data obtained by the detection, the input / output characteristic control circuit 37 controls the white balance adjustment pattern 36.
Luminance and chromaticity are measured, the data is compared with an adjustment target value (reference data), and the input / output characteristic 44 is changed so that the white balance characteristic becomes appropriate. The white balance is adjusted by the white balance adjusting circuit 41 based on this output. Then, the detection of the projection light by the photoelectric conversion element 8, the fluctuation of the input / output characteristic 44, and the white balance adjustment are repeated until the white balance becomes appropriate, and when the white balance becomes appropriate, the data of the input / output characteristic 44 is obtained. Are stored in the memory 42.

Next, by the microcomputer 35,
The adjustment pattern forming circuit 30 outputs the white balance adjustment pattern 36 with the changed brightness, the white balance adjustment is performed in the same manner as above, and when the white balance becomes appropriate, the data of the input / output characteristic 44 is stored in the memory 42. Remember. This adjustment is performed for all sampled luminances and repeated until the white balance at all luminances is proper. The above process is performed in the manufacturing process of the device, and the tone characteristic of white balance is automatically adjusted. The white balance adjustment after the device is completed is performed using the photoelectric conversion element 7 as in the seventh embodiment.

Example 12 Next, an embodiment in which the uniformity adjustment can be automated will be described. FIG. 20 is a diagram showing the relationship between the uniformity adjusting pattern projected on the panel and the photoelectric conversion element according to the twelfth embodiment of the present invention, which is viewed from the projection side when four uniformity adjusting patterns 47 are projected. The panel 6 is shown, and four photoelectric conversion elements 8 are installed in correspondence with the four uniformity adjusting patterns 47.

In the ninth embodiment, as shown in FIG. 20, the uniformity adjusting pattern 47 is projected at a plurality of different positions, and the photoelectric conversion element 8 is installed at each projected position to detect the projected light. Similar to Example 9, the adjustment was repeated so that the data obtained from all the photoelectric conversion elements 8 installed on the panel 6 would be the adjustment target value (reference data). , Data is stored in the memory 42. As described above, the uniformity is automatically adjusted in the manufacturing process of the device. The uniformity adjustment after the completion of the apparatus is performed using the photoelectric conversion element 7 as in the seventh embodiment.

Example 13 It is apparent from the eleventh and twelfth embodiments that the adjustment of the gradation characteristics of uniformity can be automated.

Example 14 Although the white balance adjustment pattern 36 and the uniformity adjustment pattern 47 are separately projected in the ninth and twelfth embodiments, the same effect can be obtained by projecting them simultaneously.

Example 15 Although the four uniformity adjustment patterns 47 are used in the twelfth embodiment, a plurality of uniformity adjustment patterns 47 may be used.

[0044]

Since the present invention is constructed as described above, it has the following effects. The adjustment pattern formed by the adjustment pattern forming circuit is detected by the photoelectric conversion element, the detected data is compared with the reference data, and the characteristics of the CRT are adjusted so that the deviation amount is minimized, so that the adjustment can be automated. In addition, it is possible to make adjustments that are not affected by environmental conditions or changes over time. Further, also in the cutoff adjustment, the adjustment can be automated, and the adjustment can be performed without being influenced by the environmental conditions and the change with time. The adjustment circuit also has a correction amount calculation circuit that compares the data detected by the photoelectric conversion element with the reference data and calculates the correction amount, and receives the correction amount from this correction amount calculation circuit to minimize the deviation amount. Is adjusted so that Further, by using the white balance adjustment pattern as the adjustment pattern, the adjustment circuit adjusts the white balance, so that the white balance adjustment can be automated and the adjustment can be performed without being influenced by environmental conditions or aging.

Further, by using the uniformity adjustment pattern as the adjustment pattern, the adjustment circuit adjusts the uniformity, so that the uniformity adjustment can be automated and the adjustment can be performed without being influenced by environmental conditions or changes with time. . Further, the adjusting circuit compares the luminance and chromaticity measuring circuit for measuring the luminance and chromaticity of the data detected by the photoelectric conversion element with the luminance and chromaticity measured by the luminance and chromaticity measuring circuit with reference data, In order to correct the error calculated by the adjustment target value error calculation circuit for calculating the difference and the adjustment target value error calculation circuit, the amplitude of the adjustment pattern is calculated based on the correction amount calculated by the correction amount calculation circuit from this error. An amplitude conversion control unit that performs conversion can be provided, and adjustment can be performed by amplitude conversion based on the correction amount. In addition, the adjustment pattern forming circuit is controlled by the microcomputer, and by sequentially changing the amplitude of the adjustment pattern signal from the low level to the peak level, adjustment is performed at each amplitude. Can be automated, and the image quality of the projection display device can be kept good. Further, by forming the adjustment pattern by the microcomputer, it is possible to sequentially change the change amount and the change speed of the amplitude of the adjustment pattern signal at a time interval that can be detected by the photoelectric conversion element, so that a constant adjustment accuracy can be obtained. It can be controlled to keep the adjustment time as short as possible.

Further, by using the white balance adjusting pattern as the adjusting pattern, the adjusting circuit can adjust the gradation characteristic of the white balance. Also, using the uniformity adjustment pattern for the adjustment pattern,
The adjustment circuit can adjust the gradation characteristics of uniformity. Further, since the adjustment pattern is formed by the microcomputer and the adjustment pattern is sequentially interrupted in the frame at each predetermined time interval, the adjustment pattern is invisible to the human eye and therefore the display screen is good. Can be kept Further, by forming the adjustment pattern by the microcomputer, the adjustment pattern is formed in a size not larger than a predetermined size and not smaller than the size detectable by the photoelectric conversion element, so that the ACL does not catch on the adjustment pattern. Does not hinder. In addition, the photoelectric conversion element
Since the panel is provided on the front surface of the screen and the adjustment in the manufacturing process is performed based on the data detected by the photoelectric conversion element, the adjustment in the manufacturing process can be automated.

Further, since a hole for transmitting light is provided on the rear surface of the projection light mirror only at a specific position on the rear surface of the reflecting mirror and a photoelectric conversion element is provided at that position to reduce the projection light to be transmitted, the display screen is obstructed. Therefore, it is possible to obtain a screen that is not affected by the deterioration of the brightness of the projected image. Furthermore, the angle between the center line of the photoelectric conversion element on the rear surface of the reflection mirror and the rear surface of the reflection mirror is made equal to the incident angle of the projection light to detect the projection light efficiently, and at the same time, the light detection part of the photoelectric conversion element and the reflection mirror. The distance from the center of the hole can be restricted so that it is not affected by light other than the light to be measured. In addition, a concave lens may be placed in front of the photoelectric conversion element on the rear surface of the reflection mirror to improve the directivity of the projected light so that it is efficiently detected and is not affected by light other than the light to be measured. it can.

Further, the photoelectric conversion element is arranged on the panel provided on the front surface of the screen, and the adjustment in the manufacturing process is performed based on the data detected by the photoelectric conversion element so as to minimize the deviation amount. Automation can be done. Further, since the photoelectric conversion element on the rear surface of the reflection mirror and the photoelectric conversion element of the panel are arranged so as to correspond to each other so as to detect the same adjustment pattern, the reference data can be taken out from the photoelectric conversion element on the rear surface of the reflection mirror. Also,
By storing the reference data obtained by the adjustment in the manufacturing process in the memory, it can be used as the reference data in the adjustment after the completion of the device. Further, the adjustment pattern is such that the amplitude of the signal is sequentially changed from the low level to the peak level and adjustment is performed at each amplitude, so that the gradation characteristic adjustment can be automated and the image quality of the projection display device can be improved. Can be kept. Further, the adjustment pattern is formed in a size not larger than a predetermined size and not smaller than a size detectable by the photoelectric conversion element, and has a size that does not catch on the ACL, so that there is no hindrance to the adjustment.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a projection display device according to Embodiment 1 of the present invention.

FIG. 2 is a schematic sectional view showing a reflection mirror in FIG.

FIG. 3 is a diagram showing a positional relationship between a reflection mirror and a photoelectric conversion element in FIG.

FIG. 4 is an adjustment pattern forming circuit of the projection display apparatus according to the first embodiment of the present invention.

FIG. 5 is a reflection mirror viewed from the projection side when a cutoff adjustment pattern is projected.

FIG. 6 is a diagram showing a feedback system of the projection display apparatus according to the first embodiment of the present invention.

FIG. 7 is a flowchart showing cutoff adjustment using the microcomputer according to the first embodiment of the present invention.

FIG. 8 is a diagram showing a relationship between an adjustment pattern and a photoelectric conversion element according to a third embodiment of the present invention.

FIG. 9 is a diagram showing a relationship between an adjustment pattern and a photoelectric conversion element according to Example 4 of the present invention.

FIG. 10 is a schematic cross-sectional view showing a projection display device when using three CRTs according to Embodiment 6 of the present invention.

FIG. 11 is a diagram showing projection light projected on a reflection mirror when using three CRTs according to Embodiment 6 of the present invention.

FIG. 12 is a diagram showing a feedback system of a projection display apparatus according to Embodiment 7 of the present invention.

FIG. 13 is a chromaticity diagram of the International Commission on Illumination (CIE).

FIG. 14 is a schematic sectional view showing a projection type display device according to Example 9 of the present invention.

FIG. 15 is a diagram showing an adjustment pattern forming circuit of a projection display apparatus according to Embodiment 9 of the present invention.

FIG. 16 is a diagram showing the relationship between the adjustment pattern projected on the panel arranged on the front surface of the screen and the photoelectric conversion element when the white balance adjustment pattern is projected according to the ninth embodiment of the present invention. Is.

FIG. 17 is a diagram showing an input / output characteristic control circuit of a projection display apparatus according to Embodiment 9 of the present invention.

FIG. 18 is a diagram showing a feedback system of the projection type display apparatus according to the ninth embodiment of the present invention.

FIG. 19 is a flowchart showing white balance adjustment using a microcomputer according to a ninth embodiment of the present invention.

FIG. 20 is a diagram showing a relationship between a uniformity adjusting pattern projected on a panel and a photoelectric conversion element according to a twelfth embodiment of the present invention.

FIG. 21 is a schematic cross-sectional view showing a conventional projection display device.

[Explanation of symbols]

1 1a, 1b, 1c, cathode ray tube (CRT), 2 2
a, 2b, 2c, projection lens, 3 reflection mirror, 4
Screen, 5a, 5b, 5c, projection light, 6
Panel, 7a, 7b, 7c, 8 photoelectric conversion element,
11 holes, 12 photodetector, 13, 30 adjustment pattern forming circuit, 20 microcomputer, 21
Cutoff adjustment pattern, 22 memory, 23 correction voltage generation circuit, 24 cutoff adjustment circuit, 25,
41 white balance adjusting circuit, 36 white balance adjusting pattern, 38 luminance / chromaticity measuring circuit, 39
Adjustment target value error calculation circuit, 40 correction amount calculation circuit, 4
2 memory, 46 amplitude conversion control circuit, 47 uniformity adjustment pattern, m hole 11 width, n distance between hole center of aluminum film and photodetector, θ angle between aluminum film and photoelectric conversion element

Claims (25)

[Claims] 1. A cathode ray tube, a projection lens arranged in front of the cathode ray tube for enlarging and projecting an image of the cathode ray tube, and a reflection arranged in front of the projection lens for reflecting an image for enlarging and projecting by the projection lens. A mirror, a screen on which an image reflected from the reflecting mirror is formed, an adjustment pattern forming circuit for forming an adjustment pattern on the cathode ray tube, the cathode pattern tube formed by the adjustment pattern forming circuit on the cathode ray tube, A photoelectric conversion element for detecting an adjustment pattern projected from the projector, and a projection circuit characterized by comprising an adjustment circuit for adjusting the characteristics of the cathode ray tube by comparing the data detected by the photoelectric conversion element with reference data. Type display device. 2. A device for displaying red, green and blue images respectively 3
Cathode ray tubes, three projection lenses arranged in front of the three cathode ray tubes corresponding to the three cathode ray tubes, and projecting images of the respective cathode ray tubes in an enlarged manner, arranged in front of each projection lens, and A reflection mirror that reflects an image to be magnified and projected, a screen on which an image reflected from the reflection mirror is formed, an adjustment pattern forming circuit that forms each adjustment pattern on the three cathode ray tubes, and an adjustment pattern forming circuit. A photoelectric conversion element which is formed on the three cathode ray tubes by the pattern forming circuit and detects the adjustment pattern projected from each of the cathode ray tubes, and by comparing the data detected by the photoelectric conversion element with the reference data, A projection display device comprising an adjusting circuit for adjusting the characteristics of three cathode ray tubes. 3. The adjustment pattern is a cut-off adjustment pattern, and the adjustment circuit has a correction voltage generation circuit that compares the data detected by the photoelectric conversion element with reference data and generates a correction voltage. 3. The projection display device according to claim 1, wherein the cutoff voltage is adjusted by receiving the correction voltage from the correction voltage generation circuit. 4. The adjustment circuit has a correction amount calculation circuit for comparing the data detected by the photoelectric conversion element with the reference data and calculating a correction amount, and receives the correction amount from the correction amount calculation circuit for adjustment. The projection display device according to claim 2, wherein the projection display device is a display device. 5. The projection display device according to claim 4, wherein the adjustment pattern is a white balance adjustment pattern, and the adjustment circuit adjusts the white balance. 6. The projection display device according to claim 4, wherein the adjustment pattern is a uniformity adjustment pattern, and the adjustment circuit adjusts the uniformity. 7. An adjustment circuit comprises a luminance / chromaticity measuring circuit for measuring the luminance and chromaticity of data detected by a photoelectric conversion element, and comparing the chromaticity measured by this luminance / chromaticity measuring circuit with reference data, An adjustment target value error calculation circuit for calculating the difference, and a correction amount calculation circuit for correcting the error calculated by the adjustment target value error calculation circuit with reference to the brightness measured by the brightness / chromaticity measurement circuit, 3. The projection display device according to claim 1, further comprising an amplitude conversion control unit that performs amplitude conversion of the adjustment pattern based on the correction amount calculated by the adjustment circuit. 8. The projection display device according to claim 7, wherein the adjustment circuit adjusts the luminance of the adjustment pattern formed by the adjustment pattern forming circuit so as not to change. 9. The adjusting pattern forming circuit is controlled by a microcomputer and is capable of sequentially changing the amplitude of the adjusting pattern signal from a low level to a peak level. A projection type display device as described in 1 above. 10. The adjusting pattern forming circuit is controlled by a microcomputer, and sequentially changes the amount of change and the changing speed of the amplitude of the adjusting pattern signal at a time interval that can be detected by the photoelectric conversion element. 9. The projection display device according to item 9. 11. The projection display device according to claim 9, wherein the adjustment pattern is a white balance adjustment pattern, and the adjustment circuit adjusts the gradation characteristic of white balance. 12. The adjustment pattern is a uniformity adjustment pattern, and the adjustment circuit adjusts the gradation characteristics of the uniformity.
The projection display device according to item 0. 13. The adjustment pattern forming circuit is controlled by a microcomputer, and causes the frames in the video signal to be sequentially interrupted by the adjustment pattern at predetermined time intervals. 9. The projection display device according to any one of 9 above. 14. The adjustment pattern forming circuit is controlled by a microcomputer, and controls the adjustment pattern to have a predetermined size or less and a size to be detected by a photoelectric conversion element or more. The projection display device according to claim 13. 15. The projection type display device according to claim 9, wherein the reference data is read from a memory by a microcomputer. 16. The projection display device according to claim 1, wherein the photoelectric conversion element is provided on a panel arranged in front of the screen. 17. The reflection mirror is provided with a hole for transmitting the projection light to the rear surface of the mirror only at the position where the adjustment pattern projected from the projection lens is projected, and the photoelectric conversion element comprises:
The projection display device according to any one of claims 1 to 15, wherein the projection display device is arranged at a position facing the hole on the rear surface of the mirror. 18. The photoelectric conversion element, wherein an angle formed by a center line of the photoelectric conversion element and a rear surface of the reflection mirror is equal to an incident angle of projection light,
18. The light detecting section for detecting the adjustment pattern of the photoelectric conversion element is arranged at a distance from the center of the hole that is not easily affected by light other than the light to be measured. Projection display device. 19. The projection display device according to claim 17, wherein a concave lens is arranged in front of the photoelectric conversion element. 20. A method of adjusting a projection display device, wherein a projection lens is arranged in front of a cathode ray tube, and an image enlarged and projected by the projection lens is reflected by a reflection mirror to be imaged on a screen. In, on the front surface of the screen, while arranging a panel having a photoelectric conversion element, the adjustment pattern formed on the cathode ray tube is detected by the photoelectric conversion element, and by comparing this detection data with reference data, A method for adjusting a projection display device, characterized in that the characteristics of the cathode ray tube are adjusted. 21. The method of adjusting a projection display device according to claim 17, wherein a photoelectric conversion device is provided on a front surface of the screen at a position corresponding to a photoelectric conversion element arranged on a rear surface of a reflection mirror. The characteristics of the cathode ray tube are adjusted by arranging a panel having a conversion element, detecting the adjustment pattern formed on the cathode ray tube by the photoelectric conversion element, and comparing the detection data with reference data. A method for adjusting a projection display device, characterized in that. 22. The method of adjusting a projection display device according to claim 21, wherein the number of photoelectric conversion elements arranged on the panel does not exceed the number of photoelectric conversion elements arranged on the rear surface of the reflection mirror. 23. The microcomputer stores the data detected by the photoelectric conversion element on the rear surface of the reflecting mirror when the characteristics of the cathode ray tube are adjusted in the manufacturing process in the memory as reference data. The method for adjusting a projection display device according to claim 22. 24. The adjustment of a projection display device according to claim 21, wherein the adjustment pattern is such that the amplitude of the signal thereof is sequentially changed from a low level to a peak level. Method. 25. The projection according to claim 21, wherein the adjustment pattern is formed in a size not larger than a predetermined size and not smaller than a size detectable by the photoelectric conversion element. Method for adjusting type display device.