JPH06236165A - Gradation correcting information generating system for liquid crystal light valve - Google Patents

Abstract

PURPOSE:To provide a system capable of efficiently generating the gradation correcting information according to the applied voltage transmissivity characteristic of a liquid crystal light valve at a high speed. CONSTITUTION:By a data processor 1, the generation of a test signal is indicated to an optional waveform generator 2 in the state that a light source 4 lights the liquid crystal valve 3. Thus, the test signal is generated by the optional waveform generator 2 to be imparted to the light valve 3, and the transmissivity is revised. At this time, the transmissivity is measured by a photometry device 7. By the data processor l, the applied voltage - transmissivity characteristic of the liquid crystal light valve 3 is caught from the indicated test signal and a transmissivity signal, and the gradation correcting information is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for creating gradation correction information (for example, applied voltage-transmittance correction information) of a liquid crystal light valve.

[0002]

2. Description of the Related Art In a liquid crystal display device, by making a video signal and a light transmittance (light transmittance) have a linear relationship,
The linear gradation of the video signal is maintained, and the display quality of the video signal can be made appropriate. However, in the liquid crystal light valve in the active matrix type liquid crystal panel, the applied voltage and the transmittance are not in a linear relationship. Therefore, it is necessary to correct the video signal in advance according to the applied voltage-transmittance characteristic of the liquid crystal light valve so that the video signal before correction and the transmittance have a linear relationship. Hereinafter, such correction will be referred to as applied voltage-transmittance correction.

Further, in the image pickup system, it is assumed that a cathode ray tube whose light emission luminance is proportional to the γth power of the input voltage (that is, the light emission luminance and the input voltage are non-linear) is applied to the video signal in the display system. On the other hand, 1 / γ power correction (so-called γ correction) is performed. However, since the γ correction is for the cathode ray tube, the γ correction is unnecessary in the liquid crystal display device. Therefore, in the liquid crystal display device, reverse correction (hereinafter, referred to as reverse γ correction) to γ correction performed in the image pickup system is performed on the video signal.

Conventionally, as an applied voltage-transmittance correction circuit,
A function generating circuit with an analog circuit configuration was used. Also,
A function generating circuit having an analog circuit configuration was also used as the inverse γ correction circuit. In practice, an applied voltage-transmittance correction circuit is provided after the inverse γ correction circuit, the inverse γ correction is applied only to the γ correction, and the applied voltage-transmittance correction is applied only to the applied voltage-transmittance characteristic. I am trying to do it.

However, the applied voltage-transmittance characteristic of a liquid crystal light valve has a curve that is difficult to represent with one function, and even if it is approximated, it is expressed using a combination of three or more curves and straight lines. It is what is done.
Therefore, the correction circuit for performing the applied voltage-transmittance correction becomes complicated, and it is difficult to obtain an appropriate correction curve for the applied voltage-transmittance characteristic. Further, the correction curve theoretically obtained has a steep shape, and in such a steep shape portion, the output voltage naturally changes greatly with a slight difference in the input voltage, and the correction curve There is a problem that it is difficult to obtain a suitable curve. Therefore, according to the conventional correction method using the analog circuit, the applied voltage-transmittance correction is insufficient and the display image quality is deteriorated.

On the other hand, the inverse γ correction curve can be expressed by one function. However, even if it can be represented by a single function, its shape is a non-linear shape, and therefore it is difficult to properly realize it with a function generating circuit having an analog circuit configuration. There were some things that couldn't be done.

As described above, both the corrections for the gradation of the video signal are insufficient, and the video signals subjected to the both corrections become improper than the combination of the insufficient degrees by the respective corrections. In the past, a large deterioration in image quality could not be avoided.

Therefore, the same applicant applied voltage-
Use the conversion table to perform transmittance correction,
Perform the correction using the conversion table, and
It has already been proposed that a single conversion table be used to perform a combined correction of transmittance correction and inverse γ correction (Japanese Patent Application No. 2-408806 and drawings).

The inverse γ correction curve is uniquely determined regardless of the type of liquid crystal light valve. On the other hand, the applied voltage-transmittance correction curve and the combined curve of the applied voltage-transmittance correction curve and the inverse γ correction curve differ depending on the type of liquid crystal light valve, and even if they are of the same type. It also varies slightly depending on each liquid crystal light valve product.

Therefore, when the applied voltage-transmittance correction is performed by using a conversion table, or when the combined correction of the applied voltage-transmittance correction and the inverse γ correction is performed by using one conversion table, the product is For each type or each product (or each lot), the applied voltage-transmittance characteristic of the liquid crystal light valve is measured to obtain a correction curve, and the correction data is calculated to create a conversion table.

[0011]

However, the operation of measuring the applied voltage-transmittance characteristic and the operation of creating the correction data according to the correction curve from the obtained applied voltage-transmittance characteristic are performed to once obtain the correction data. Even if so, the above-mentioned operation is repeated for the confirmation. Therefore, complicated operations are required and time is required to obtain final correction data. Even if the software processing is used for the operation of obtaining the correction data from the obtained applied voltage-transmittance characteristic, it takes much time and effort. Therefore, it is practically impossible to create correction data for each product.

The present invention has been made in view of the above points, and is a floor of a liquid crystal light valve capable of efficiently creating gradation correction information according to the applied voltage-transmittance characteristic of the liquid crystal light valve in a short time. It is intended to provide a tonal correction information creation system.

[0013]

In order to solve such a problem, in the present invention, a light source for illuminating a liquid crystal light valve, a test signal generating means for generating a test signal for the liquid crystal light valve, and a liquid crystal light valve are transmitted. The photometric means for receiving the generated light beam and outputting the transmittance signal and the test signal generating means for instructing the test signal generation means to apply the voltage to the liquid crystal light valve based on the transmittance signal given from the photometric means-transmission A data processing means for capturing the gradation characteristic by capturing the rate characteristic and a gradation correction information generating system for the liquid crystal light valve for generating the gradation correction information having a linear relationship with the gradation characteristic of the liquid crystal light valve are configured. .

Here, the data processing means causes the test signal generating means to generate a test signal utilizing the gradation correction information once obtained, and the gradation correction information of the gradation correction information is generated based on the transmittance signal from the photometric means. If the validity is judged, and if it is not correct, the gradation correction information is corrected, the test signal is generated again, and the validity judgment is repeated to obtain the gradation correction information having the linear relationship of the gradation characteristics of the liquid crystal light valve. It is preferable to obtain it finally.

It is preferable that a digital memory for storing gradation correction information is provided and the data processing means stores the gradation correction information created in this digital memory.

Further, the test signal generating means generates an arbitrary waveform signal according to the command signal from the data processing means, a digital memory for storing gradation correction information, and the arbitrary waveform generating means. And a liquid crystal drive unit for driving the liquid crystal light valve after correcting the signal from the gradation correction information stored in the digital memory. In this case, it is naturally unnecessary to provide a digital memory for collecting and storing the created gradation correction information.

[0017]

In the gradation correction information creating system for the liquid crystal light valve of the present invention, the data processing means instructs the test signal generating means to generate the test signal while the light source illuminates the liquid crystal light valve. Then, the test signal generating means generates a test signal and applies it to the liquid crystal light valve to change the transmittance. At this time, the photometric means measures the transmittance and gives the transmittance signal to the data processing means. The data processing means captures the applied voltage-transmittance characteristic of the liquid crystal light valve from the instructed test signal and the transmittance signal and creates gradation correction information. In this way, it is possible to realize a system that can efficiently create gradation correction information in a short time.

Here, it is desirable to confirm whether or not the created gradation correction information is valid. Therefore, the data processing means causes the test signal generating means to generate a test signal using the gradation correction information once obtained, and judges the validity of the gradation correction information based on the transmittance signal from the photometric means. If it is not appropriate, it is preferable to correct the gradation correction information and repeat the validity judgment.

It is desirable to perform the operation of storing the gradation correction information created by the system in such a digital memory.

The test signal generating means includes an arbitrary waveform generating section for generating an arbitrary waveform signal according to a command signal from the data processing means, a digital memory for storing gradation correction information, and the arbitrary waveform generating section. If it is configured with a liquid crystal drive unit that drives the liquid crystal light valve after correcting the signal from the gradation correction information stored in the digital memory, the applied voltage-transmittance characteristic The measurement can be performed.

[0021]

【Example】

(1) First Embodiment Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. The first embodiment relates to a system for measuring applied voltage-transmittance characteristics and creating correction data in a state where a liquid crystal drive circuit is not incorporated in a liquid crystal light valve.

(1-1) Configuration of the First Embodiment FIG. 1 is a block diagram showing the overall configuration of the first embodiment system. In FIG. 1, a data processing device 1 controls the entire system according to a process shown in FIG. 2 described later, and finally writes correction data in a correction digital memory (ROM) forming a conversion table. It is something that makes you The data processor 1 causes the arbitrary waveform generator 2 to output an arbitrary waveform voltage signal (test signal) when measuring the applied voltage-transmittance characteristic and confirming the linearity of the correction data once created. Control.
The arbitrary waveform generator 2 generates an arbitrary waveform voltage signal (corresponding to a video signal) centered on the command voltage from the data processing device 1 and supplies this to the liquid crystal light valve 3 as a liquid crystal drive signal.

Liquid crystal light valve 3 in this embodiment
Is short-circuited in the X and Y directions.
That is, a cell in which all cells are simultaneously switched according to a liquid crystal drive signal is used.

A backlight light source 4 is provided on one side of the liquid crystal light valve 3 and a light beam capturing probe 5 for capturing a light beam passing through the liquid crystal light valve 3 is provided on the other side. The light beam captured by the probe 5 is given to the photometric device 7 via the optical fiber 6, for example. The liquid crystal light valve 3 has almost the same applied voltage-transmittance characteristic at any position, and the probe 5 may be installed at any position as long as it faces the transparent surface of the liquid crystal light valve 3.

When a liquid crystal light valve 3 having a color filter having a mosaic arrangement of three primary colors R, G, and B is used, a white light source is used as the light source 4 and a spectrometer is used as the photometric device 7. To use. In this case,
From the spectrum data from the spectrometer, the data of the brightness or radiant flux in the three wavelength bands of red, blue and green (the relationship between radiant flux and brightness is radiant flux x luminosity characteristic = brightness) ( This represents the transmittance) is taken in by the data processing device 1.

The liquid crystal light valve 3 is provided with a red, blue or green single color filter and the backlight light source 4 is used.
As the backlight light source 4 without filtering the liquid crystal light valve 3,
Each primary color signal R, using either a blue or green monochromatic light source,
When creating the correction data for G and B, a luminance meter is used as the photometric device 7. In this case, the luminance data of one of the primary color signals (also representing the transmittance) is loaded into the data processing device 1.

A data writing device 9 for a correction digital memory (for example, a ROM) 8 is connected to the data processing device 1, and the data processing device 1 executes the process shown in FIG. The correction data is written in this data writing device 9
Then, the control is performed so as to write to the correction digital memory 8.

(1-2) Processing in the First Embodiment Next, processing for a certain primary color signal executed by the data processing apparatus 1 will be described with reference to FIG. Here, FIG. 2A shows a main routine, FIG. 2B shows a subroutine showing a specific process of measuring the applied voltage-transmittance characteristic, and FIG. 2C shows a characteristic after the correction process. It shows a specific subroutine for confirming linearity.

The data processing apparatus 1 first initializes the system and then performs the first applied voltage-transmittance characteristic measurement processing (steps SP1 and SP).
2). Then, the range of the input voltage to be corrected is set based on the measurement result (step SP3). For example,
The range from the minimum value to the maximum value of the input voltage at which the transmittance of the liquid crystal light valve 3 is variable is set.

Subsequently, the data processing device 1 measures the second transmittance using the input voltage in the set range as the applied voltage (step SP4). Here, the variable range of the applied voltage differs between the first time and the second time as described above, and since the second measurement is the main measurement, the voltage variable step is also fine.

When the applied voltage-transmittance characteristic is obtained in this way, correction data is created as described later (step SP5). Here, the applied voltage, the transmittance, and the correction data are all normalized and handled. For example, the minimum value of the applied voltage is normalized to 0 and the maximum value is set to 1, and the corresponding transmittance is also normalized to the minimum value of 0 and the maximum value of 1, and the input voltage is corrected to the applied voltage. Also in the correction data, the input voltage before correction and the applied voltage after correction are normalized so that the minimum value is 0 and the maximum value is 1. In the case of this embodiment, the correction data obtained by the processing of this step is stored in the buffer memory in the data processing device 1.

When the correction data is obtained, the obtained correction data is reviewed. That is, when the correction data is applied, it is confirmed whether the input voltage before correction (not the applied voltage) and the transmittance have a linear relationship (step SP).
6). When the correction data is not appropriate by such processing, the correction data is corrected in this linear relationship confirmation processing.

In this way, the input voltage (voltage before correction)
When the linear relationship between the transmittance and the transmittance is obtained, the final correction data is given to the data writing device 9 for the correction digital memory (for example, ROM) 8 and the final correction data is supplied by the data writing device 9. The correction digital memory 8 is written (step SP7).

Next, the applied voltage-transmittance characteristic measurement process in step SP2 or SP4 will be described in detail with reference to FIG.

In such processing, first, the minimum value is set as the applied voltage (step SP10). As a result, the liquid crystal drive signal corresponding thereto is output from the arbitrary waveform generator 2 and the transmittance control operation of the liquid crystal light valve 3 is performed.
Here, since the first measurement process (step SP2) is for obtaining the range of the input voltage to be corrected, this minimum value is a sufficiently small value and is set in the second measurement process (step SP4). It is the minimum value of the range.

Next, it is confirmed that the current target voltage is not the maximum value of the measurement range (step SP11), and the output data of the photometric device 7 at that time is fetched (step SP1).
2). That is, the transmittance for the current target voltage is measured. In this case as well, since the first measurement process is for obtaining the range of the input voltage to be corrected, this maximum value is a sufficiently large value, and the second measurement process has the maximum value within the set range. Is.

When the measurement of the transmittance with respect to a certain voltage is completed in this way, the voltage to be measured is increased by the amount corresponding to the measurement resolution and the process returns to step SP11 described above (step SP13).

By repeating the processing loop consisting of steps SP11 to SP13, it is possible to measure the transmittance for each voltage that differs by the measurement resolution from the minimum value to the maximum value, and complete the measurement of the transmittance for the maximum value voltage. Then, a positive result is obtained in step SP11, and the process returns to the main routine (FIG. 2 (A)).

Next, when the correction data is applied, the processing of step SP6 for confirming whether or not the input voltage (not the applied voltage) before correction and the transmittance have a linear relationship is shown in FIG. ) For details.

Upon entering such processing, the data processing apparatus 1 first sets the corrected minimum voltage as the applied voltage by correcting the minimum voltage of the input voltage range to be corrected using the correction data corresponding to the voltage ( Step SP20).
As a result, the liquid crystal drive signal corresponding thereto is output from the arbitrary waveform generator 2 and the transmittance control operation of the liquid crystal light valve 3 is performed.

Next, it is confirmed that the current target input voltage is not the maximum value (step SP21), and the output data of the photometric device 7 at that time is fetched (step SP22).
That is, the transmittance for the current target voltage after correction is measured. Then, it is determined whether or not this transmittance has a linear relationship with the voltage value before correction, based on whether or not the error with the transmittance when there is a linear relationship is within a predetermined specified value (step SP23).

If a negative result is obtained in this determination, the correction data is corrected according to the error at that time, and the corrected voltage given to the arbitrary waveform generating device 2 is also changed, and the above step S is executed.
It returns to P22 (step SP24). On the other hand, if a positive result is obtained in this determination, the current uncorrected voltage before correction is increased by a predetermined voltage, and the above-described step SP21 is performed.
Return to step SP25.

In this way, it is possible to confirm whether or not there is a linear relationship between the input voltage and the transmittance by the voltage obtained by correcting each input voltage using the corresponding correction data, and a negative result was obtained. In this case, the correction data can be modified so as to satisfy the linear relationship, and when the process for the maximum value of the input voltage is completed, the process returns to the main routine.

(1-3) Method for Creating Correction Data Next, a method for creating correction data by the processing in step SP5 will be described in detail with reference to the drawings.

FIG. 3 is an explanatory diagram showing the relationship between the normalized applied voltage-transmittance characteristic curve and the applied voltage-transmittance correction curve for the liquid crystal light valve 3. The voltage applied to the liquid crystal light valve 3 (horizontal axis x) and the transmittance at the applied voltage (vertical axis y) have an S-shaped curve relationship as shown by the curve C1 in FIG. Here, in order to make the input voltage before correction (corresponding to the video signal voltage during normal display operation) and the transmittance have a linear relationship as shown by the dotted line C2 in FIG. Even if the input voltage is corrected and the characteristic shown in the curve C1 is applied to the corrected voltage (applied voltage), a dotted line C2 is shown between the original input voltage and the transmittance. It is necessary to make such a linear relationship. Here, such a correction curve C3 is a line symmetrical to the curve C1 with respect to the dotted line C2 in the normalized coordinate system.
Therefore, in order to obtain the correction curve C3, as described above, first, the applied voltage-transmittance characteristic curve C1 may be obtained, and then the inverse characteristic of the curve C1 may be obtained. The input / output relationship of each point on the applied voltage-transmittance correction curve C3 is correction data obtained. Therefore, if the applied voltage-transmittance correction curve C3 is obtained from the applied voltage-transmittance characteristic curve C1 obtained as a result of the measurement, the correction data can be obtained as a result.

As a method of obtaining the applied voltage-transmittance correction curve C3 from the applied voltage-transmittance characteristic curve C1, there are a method of detecting a symmetrical point on the graph and a method of function approximation.

First, a method of detecting a symmetry point on the graph will be described with reference to FIG. It is assumed that attention is paid to a certain point A on the applied voltage-transmittance characteristic curve C1. Then, the distance L of this point A with respect to the dotted line C2 having a linear relationship and the point B on the dotted line C2 that defines this distance L are obtained. Next, a point D passing through the point B and separated from the dotted line C2 by a distance L is obtained. The applied voltage-transmittance characteristic curve C3 is obtained by performing such processing for all points of the applied voltage-transmittance characteristic curve C1.

Next, a method based on function approximation will be described with reference to FIG. For details of the function approximation method, refer to Japanese Patent Application No.
2-408806 and the drawings.

In this method, the applied voltage-transmittance characteristic curve C
1 is approximated by a function, and the inverse function is calculated to obtain the applied voltage −
This is a method of obtaining the transmittance correction curve C3. Here, since the applied voltage-transmittance characteristic curve C1 is an S-shaped curve as described above, it is difficult to represent it by one function. Therefore, the central portion of the applied voltage-transmittance characteristic curve C1 is approximated by a straight line, and the front and rear thereof are approximated by a predetermined function curve.

FIG. 4 is an explanatory diagram of each such approximate function. As shown in FIG. 4, the curve portion on the coordinate origin side is represented by the function y = f (x), the central portion is represented by the function y = g (x), and the curve portion having a larger value is represented by the function y = h. (X)
It is represented by. Further, the connection point coordinates of the function f (x) and the function g (x) are represented by E (P1, Q1), and the function g (x) and the function h
The connection point coordinates with (x) are represented by F (P2, Q2). Then, each function f (x), g (x), h (x)
It was decided to approximate with Eqs. (1), (2), and (3).

Y = f (x) = a1.x ^b1 (1) (a1 and b1 are constants, and x and y are 0 ≦.
x = P1, 0≤y <Q1) y = g (x) = a2.x + c2 (2) (a2 and c2 are constants, and x and y are P1 respectively.
Y = h (x) = a3 (1-x) ^b3 (3) (a3 and b3 are constants, and x and y are P2, respectively) ^≤x <P2, Q1 ≤y <Q2
.Ltoreq.x <1, Q2 .ltoreq.y <1.) In this way, the applied voltage-transmittance characteristic curve C1 is expressed by the function f
When approximated using (x), g (x), and h (x), the applied voltage-transmittance correction curve C3 shows the inverse function f ^{−1 of} these as described above and as shown in FIG. (X), g
It can be approximated by using ⁻¹ (x) and h ⁻¹ (x).

The specific processing procedure for obtaining the applied voltage-transmittance correction curve C3 from the applied voltage-transmittance characteristic curve C1 obtained by the measurement is as follows.

First, based on the differential coefficient of each point of the applied voltage-transmittance characteristic curve C1, the curve C1 is divided into the first curve portion, the straight line portion and the second curve portion, and the division points E, Capture the coordinates of F. Intermediate points G and H are determined for each of the first and second curve portions, and their coordinates are captured. Coefficients a1 to a3, b1, b3 and c2 for specifying the approximate functions f (x), g (x) and h (x) are calculated.
Using these coefficients, the inverse functions f ⁻¹ (x), g ⁻¹ (x), h
^-1 (x) is calculated. Each inverse function f ⁻¹ (x), g ⁻¹ (x),
Clarify the range to which h ⁻¹ (x) is applied. And
The corrected value corresponding to the value of the input value (point in the x direction) is determined for the entire range of the input value.

(1-4) Effects of the First Embodiment Therefore, according to the first embodiment, the gradation correction information according to the applied voltage-transmittance characteristic of the liquid crystal light valve can be efficiently created in a short time, It is possible to realize a gradation correction information creation system for a liquid crystal light valve that can be stored in the correction digital memory.

The target for which the correction data is created by applying such a system may be each type of liquid crystal light valve, or may be the same type or each lot or each product. good. In the latter case, the effect that the correction data can be efficiently created and stored is a great effect.

(1-5) Modification of First Embodiment In the above description, it is assumed that the voltage signal applied from the data processing device 1 to the arbitrary waveform generating device 2 is not subjected to γ correction, and the liquid crystal light valve 3 Although the one that creates the correction data corresponding to the applied voltage-transmittance characteristic is shown, it is possible to create the correction data that simultaneously performs the applied voltage-transmittance correction and the inverse γ correction from the measured applied voltage-transmittance characteristic. You can For example, the inverse γ correction data is stored in the data processing device 1 in advance, and the obtained applied voltage-transmittance correction data and the inverse γ correction data stored in advance are combined to the correction digital memory 8. Correction data may be created.

In the above-mentioned first embodiment, the one for the color liquid crystal light valve 3 is shown, but the contents of this embodiment are applied to the creation and storage of the correction data for the black and white liquid crystal light valve. can do. Here, by applying a white light source as the backlight light source 4 and a luminance meter as the photometric device 7, it is possible to deal with black and white.

Further, although it has been shown that the corrected voltage signal is given to the arbitrary waveform generator 2 when the correction data once obtained is confirmed, the correction data is also given to the arbitrary waveform generator 2 to generate the arbitrary waveform. You may make it the apparatus 2 perform a correction process.

(2) Second Embodiment Next, a second embodiment system of the present invention will be described with reference to the drawings. The second embodiment differs from the first embodiment in that the measuring system for the applied voltage-transmittance characteristic has a correction digital memory and a liquid crystal drive circuit.

FIG. 5 is a block diagram showing the overall construction of the second embodiment, and the parts corresponding to those in FIG. 1 are designated by the same reference numerals. In FIG. 5, the data processor 1 of this embodiment outputs a voltage signal for which the applied voltage-transmittance correction is not executed to the arbitrary waveform generator 3 in any processing stage. This point is different from the data processing device in the first embodiment.

The arbitrary waveform generator 3 of this embodiment complies with a television signal format having a horizontal synchronizing signal and a vertical synchronizing signal, and its image portion has an arbitrary waveform centered on the voltage signal from the data processor 1. The generated video signal is generated and given to the liquid crystal drive circuit 10. A correction digital memory 8 is provided in association with the liquid crystal drive circuit 10. The liquid crystal drive circuit 10 corrects the video signal from the arbitrary waveform generator 3 using the correction digital memory 8 and a liquid crystal light valve. Drive 3 The correction data output by the data processing device 1 is written in the correction digital memory 8 by the data writing device 9.

The liquid crystal light valve 3 of this embodiment is different from the liquid crystal light valve of the first embodiment in which the X direction and the Y direction are short-circuited, and the cell under the drive control of the liquid crystal drive circuit 10 has the transmittance control. It is what is done.

The backlight source 4, the probe 5, the optical fiber 6, and the photometric device 7 in the second embodiment are the same as those in the first embodiment, and detailed description thereof will be omitted.

Next, the flow of processing in the second embodiment will be described. The basic flow is almost the same as the process flow of the first embodiment.

First, the data processing device 1 initializes the system. At this time, the correction digital memory 8
Stores the correction data having a linear relationship, that is, the correction data for which the correction is not executed. In such a state, the arbitrary waveform generator 2 outputs a video signal having a predetermined voltage in the video section, preliminary measurement of the applied voltage-transmittance characteristic at the predetermined voltage is performed, and the predetermined voltage is sequentially applied. By changing it, preliminary measurement of the applied voltage-transmittance characteristic over the entire voltage range is performed. At this time, since the correction digital memory 8 stores the correction data having the linear relationship, the liquid crystal drive circuit 10 drives the liquid crystal light valve 3 by the video signal from the arbitrary waveform generator 2. become.

After that, the range of the input voltage to be corrected is set based on the measurement result. Then, the data processing device 1 causes the arbitrary waveform generating device 2 to output a video signal in which a certain input voltage signal within the set range is set as the center voltage of the video portion, measures the transmittance, and gradually receives the input voltage signal. The applied voltage-transmittance characteristic is measured for the entire set range by converting to. Also at this time, the video signal is not corrected.

When the applied voltage-transmittance characteristic is obtained in this manner, correction data is created in the same manner as in the first embodiment, and the created correction data is stored in the correction digital memory 8. Then, the transmittance measurement is performed in the same manner as the first and second transmittance measurements. At this time, since the correction data is stored in the correction digital memory 8, the video signal output by the arbitrary waveform generator 2 is corrected in the liquid crystal light valve 3 after being corrected in accordance with the stored correction data. Supplied.

The data processor 1 confirms the validity of the correction data based on the transmittance measured at this time. If there is invalid correction data, it is corrected and the correction digital memory 8 is updated to reconfirm the validity of the corrected correction data. If all the ranges are valid, the series of processing ends.

Therefore, also in this second embodiment, the first
The same effect as that of the embodiment can be obtained.

As a modification of the second embodiment, the present invention can be applied to a black and white light valve and the applied voltage-
It is conceivable to obtain combined correction data of the transmittance correction and the inverse γ correction.

(3) Third Embodiment Next, a third embodiment system of the present invention will be described in detail with reference to the drawings. The third embodiment relates to a liquid crystal light valve used in a projection type display device such as a liquid crystal projector. FIG. 6 is a block diagram showing the overall configuration of this third embodiment, and FIG. 7 is an explanatory diagram of the probe installation position.

As shown in FIG. 6, the structure of the third embodiment has substantially the same structure as that of the second embodiment. However, since it is a projection type, the illumination light source 4 is used as a light source, the screen 11 is provided for receiving the light rays transmitted through the liquid crystal light valve 3, and the installation position of the probe 5 is as shown in FIG. The present invention is not limited to the back side of the bulb 3, but rather the front side of the screen 11 is preferable if the screen 11 is a reflective type, and the rear side of the screen 11 is preferable if the screen 11 is a transmissive type. The application point is different from the second embodiment.

As described above, the process flow is the same as that of the second embodiment, though there are some differences in the configuration, and therefore the description thereof is omitted.

Also according to this third embodiment, the first and second
The same effect as that of the embodiment can be obtained. The system for the liquid crystal light valve used in the projection type display device is more suitable than the systems of the first and second embodiments.

As a modification of the third embodiment, the present invention can be applied to a black and white light valve and the applied voltage-
It is conceivable to obtain combined correction data of the transmittance correction and the inverse γ correction.

(4) Other Embodiments The correction digital memory 8 in the above system may be directly incorporated in a product, or may be a master for copying a large number of digital memories. For example, the latter applies when the same correction data is applied to the same type of liquid crystal light valve.

[0077]

As described above, according to the present invention, the applied voltage-transmittance characteristic of the liquid crystal light valve can be measured and the gradation correction information can be efficiently measured in a short time from the obtained applied voltage-transmittance characteristic. It is possible to realize the gradation correction information creation system of the liquid crystal light valve that can be executed in.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a system according to a first embodiment.

FIG. 2 is a flowchart showing a processing flow of the system of the first embodiment.

FIG. 3 is an explanatory diagram (1) of a method of creating correction data.

FIG. 4 is an explanatory view (No. 2) of a method of creating correction data.

FIG. 5 is a block diagram showing the configuration of a second embodiment system.

FIG. 6 is a block diagram showing a configuration of a system of a third embodiment.

FIG. 7 is an explanatory diagram of an installation position of a light receiving probe of the third embodiment system.

[Explanation of symbols]

1 ... Data processing device, 2 ... Arbitrary waveform generating device, 3 ... Liquid crystal light valve, 4 ... Light source, 5 ... Light receiving probe, 6 ... Optical fiber, 7 ... Photometric device, 8 ... Correction digital memory,
9 ... Data writing device, 10 ... Liquid crystal drive circuit, 11 ... Screen.

Claims (4)

[Claims] 1. A gradation correction information creating system for a liquid crystal light valve, which creates gradation correction information having a gradation characteristic of a liquid crystal light valve as a linear relationship, comprising: a light source for illuminating the liquid crystal light valve; Test signal generating means for generating a test signal for the light valve, photometric means for receiving a light beam transmitted through the liquid crystal light valve and outputting a transmittance signal, and instructing the test signal generating means to generate a test signal. At this time, the liquid crystal light valve is provided with a data processing means for creating gradation correction information by capturing the applied voltage-transmittance characteristic of the liquid crystal light valve based on the transmittance signal given from the photometric means. Gradation correction information creation system. 2. The data processing means causes the test signal generating means to generate a test signal using the gradation correction information once obtained, and the gradation correction information is generated based on the transmittance signal from the photometric means. Of the liquid crystal light valve is linearly related to the gradation characteristics of the liquid crystal light valve. The gradation correction information creation system for a liquid crystal light valve according to claim 1, wherein information is finally obtained. 3. A digital memory for storing gradation correction information, wherein the data processing means stores the gradation correction information obtained in the digital memory. LCD light valve gradation correction information creation system. 4. An arbitrary waveform generator for generating a signal of an arbitrary waveform according to a command signal from said data processing means, said test signal generating means, a digital memory for storing gradation correction information, and said arbitrary waveform. 3. The liquid crystal drive unit for driving the liquid crystal light valve after correcting the signal from the generation unit by the gradation correction information stored in the digital memory, The liquid crystal drive unit according to claim 1 or 2, LCD light valve gradation correction information creation system.