JPH085974A - Liquid crystal tester - Google Patents

Abstract

PURPOSE:To provide a liquid crystal tester for rapidly obtaining an optimum gradation driving method by automatically measuring the response characteristic of a liquid crystal display cell and executing analysis processing of data in order to obtain the optimum response speed of the liquid crystal display cell and an improvement of display quality. CONSTITUTION:A CPU 3b sets the data for changing the control patterns of various kinds of the gradation control methods for setting the liquid crystal driving control signal to execute gradation control of the liquid crystal display cell 20 to be tested at the time of a response speed measurement test and outputs this data to a liquid crystal driving control section 4d within an LCD driving device 4. The CPU forms an environmental temp. setting signal for setting the environmental temp. in an environmental testing chamber 2 and outputs this signal to the environmental testing chamber 2, thereby changing the enviromnental temp. The CPU executes processing to control the environmental temp. setting process in order to obtain the desired environmental temp. for the liquid crystal display cell 20 to be tested and to output a report on the result of the response speed measurement, characteristic graph, etc., of the liquid crystal display cell 20 to be tested according to a management program of the measurement data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal test apparatus for testing a liquid crystal display cell under test, and more specifically, for measuring the response speed of the liquid crystal display cell under test to obtain an optimum driving speed. The present invention relates to a liquid crystal test device for testing the gray scale driving method of.

[0002]

2. Description of the Related Art FIG. 10 shows a response characteristic graph when a response characteristic test of a liquid crystal display cell under test is conducted by a conventional liquid crystal test apparatus. The response characteristic graph shown in FIG. 10 is obtained by setting the environmental temperature in the environment tank in which the liquid crystal display cell under test is installed as T1 ° C, T2 ° C, T3 ° C, and using the test liquid crystal drive unit. Response time Tr1 when the adjustment drive range is changed from the halftone brightness level to the bright level, and response time T when the dark level brightness is changed to the bright level
It is a measurement result of r2.

It can be seen from this response characteristic graph that the liquid crystal display cell under test has a response time Tr1 and a dark level when the range of gradation driving is changed from a halftone luminance level to a bright level. It means that there is a time difference in the response time Tr2 when the brightness is changed from the brightness of 1 to the brightness of the bright level.

Since this difference in response time causes flickering of the display screen in a liquid crystal television, a liquid crystal driving method for obtaining a uniform response speed that eliminates the difference in response speed between these luminance levels is tested for response characteristics. Is required in order to provide a high quality display image in a liquid crystal display device using a liquid crystal display cell.

Further, conventionally, as a liquid crystal driving method for obtaining an optimum response speed, there is a method of storing display data for each frame in a memory and performing pulse width gradation control by comparing and judging gradation between frames. there were.

[0006]

However, in the response characteristic test by such a conventional liquid crystal test device, the liquid crystal test device is configured in accordance with the test environment corresponding to each liquid crystal display cell under test, Since it is necessary to manually adjust the test environment and process the measurement data to create the response characteristic graph as shown in FIG. 10 each time, the work efficiency of the tester is lowered. There was a point.

Further, as a liquid crystal driving method for obtaining an optimum response speed, there is a method of storing display data for each frame in a memory and performing pulse width gradation control by comparing and judging gradation between frames. However, since the temperature characteristic of the liquid crystal display cell was not taken into consideration, that is, the pulse width gradation control was not performed in consideration of the change of the response characteristic due to the change of the actual temperature of the liquid crystal display cell.

It is an object of the present invention to automatically measure the response characteristics of the liquid crystal display cell and analyze the data in order to obtain the optimum response speed of the liquid crystal display cell and improvement of the display quality. An object of the present invention is to provide a liquid crystal test device for obtaining an optimum gradation driving method.

[0009]

According to the first aspect of the present invention,
A light source for irradiating light to the liquid crystal display cell under test installed in a predetermined tank, a liquid crystal driving means for generating a liquid crystal drive signal for gradation driving of the liquid crystal display cell under test, and the inside of the tank. Test environment setting means for setting various test environments, brightness detecting means for detecting the brightness level of transmitted light or reflected light of the light emitted from the light source to the liquid crystal display cell under test, and the liquid crystal driving means. Information processing means for performing information processing for controlling the gradation driving pattern set by the liquid crystal driving signal, and for performing information processing for controlling the setting condition of the test environment set by the test environment setting means. And is provided.

Further, in this case, as described in claim 2, liquid crystal temperature detecting means for directly detecting the temperature of the liquid crystal display cell under test is provided, and the information processing means is a gradation driving pattern. The liquid crystal to be tested is based on the brightness detected by the brightness detecting means and the temperature of the liquid crystal display cell under test detected by the liquid crystal temperature detecting means corresponding to the control and setting condition control of the test environment. It is more effective to perform information processing to evaluate the response characteristics of the display cell in various test environments.

Further, as described in claim 3, it is effective that the information processing means controls the set temperature for setting the environment temperature in the tank by the environment setting means.

Further, as described in claim 4, the information processing means has a storage means for storing a test program for executing the pattern control of the gradation drive and the control of the test environment, It is effective to sequentially execute the response speed evaluation test of the liquid crystal display cell under test based on a program.

Further, as described in claim 5, when the information processing means performs the information processing for evaluating the response characteristic of the liquid crystal display cell under test, the luminance detecting means showing the response characteristic. It is effective to sample the change in the brightness level detected by the method every predetermined time and compare the sampled data with a predetermined reference value.

Further, as described in claim 6, the information processing means preliminarily sets a plurality of first brightness level data serving as a reference and second brightness level data different from the first brightness level data. The brightness level detected by the brightness detecting means is stored as a set, and when the information processing for evaluating the response characteristics of the liquid crystal display cell under test is performed,
Measuring a plurality of response times from the first luminance level to reaching the second luminance level, and controlling the liquid crystal driving signal generated by the liquid crystal driving means so that the difference between the respective response times is minimized. Is effective.

[0015]

According to the first aspect of the invention, the brightness level due to the transmitted light or the reflected light of the light emitted from the light source to the liquid crystal display cell under test installed in the predetermined tank is detected by the brightness detecting means. The information processing means performs information processing for controlling a gradation driving pattern set by a liquid crystal driving signal for gradation driving generated by the liquid crystal driving means, and a test set by the test environment setting means. Performs information processing to control environment setting conditions.

Therefore, it is possible to easily find the optimum gradation driving method for the liquid crystal display cell under test, and as a result, it is possible to obtain stable display quality without flicker in the liquid crystal display device.

According to a second aspect of the present invention, a liquid crystal temperature detecting means for directly detecting the temperature of the liquid crystal display cell under test is provided, and the information processing means controls the gradation driving pattern and Based on the brightness detected by the brightness detecting means and the temperature of the liquid crystal display cell under test detected by the liquid crystal temperature detecting means corresponding to the control of the setting conditions of the test environment, the liquid crystal display cell for the test is tested. Since the information processing for evaluating the response characteristics in various test environments is performed, the characteristic test of the liquid crystal can be rationalized and processed in a short time. Further, the temperature measurement error can be reduced as compared with the conventional ambient temperature measurement.

According to the third aspect of the present invention, the information processing means controls the set temperature for setting the environmental temperature in the tank by the environment setting means, whereby the liquid crystal display cell under test is controlled. The environmental temperature can be easily controlled.

According to a fourth aspect of the present invention, the information processing means has a storage means for storing a test program for executing the gradation drive pattern control and the test environment control. By sequentially executing the response speed evaluation test of the liquid crystal display cell under test based on the above, the test work can be smoothly performed, and the flexible test can be performed by a simple program change. The work load on the person in charge can be significantly reduced.

According to a fifth aspect of the present invention, the information processing means uses the luminance detecting means indicating the response characteristic when performing information processing for evaluating the response characteristic of the liquid crystal display cell under test. By sampling the change in the detected brightness level at every predetermined time and comparing the sampling data with a predetermined reference value, it is possible to easily determine the optimum response characteristic of the liquid crystal display cell. The determination result can be used for standardization of quality control of liquid crystal display cells.

According to a sixth aspect of the present invention, the information processing means stores in advance first reference brightness level data,
When a plurality of sets of the first brightness level data and the second brightness level data different from each other are stored and information processing for evaluating the response characteristic of the liquid crystal display cell under test is performed, it is detected by the brightness detecting means. A liquid crystal drive generated by the liquid crystal drive means by measuring a plurality of response times until the luminance level reaches the second luminance level from the first luminance level, and minimizing the difference between the response times. By controlling the signal, the optimum response characteristic of the liquid crystal display cell can be automatically determined, and the optimum response characteristic of the liquid crystal display cell can be automatically determined. It is possible to omit the work of evaluating and determining the pattern that gives the optimum response speed from each pattern of the gradation control method set in the drive signal, further reducing the work load on the person in charge of testing. Rukoto can. Further, by selecting a gradation control method, it is possible to easily respond to a response characteristic test of a new liquid crystal display cell, and it is possible to expand the range of use of the liquid crystal test device.

[0022]

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 9 are views showing an embodiment of the liquid crystal test apparatus of the present invention. First, the configuration will be described.
FIG. 1 is a diagram showing an overall configuration of a liquid crystal test apparatus 1.

In FIG. 1, the liquid crystal test device 1 is composed of an environmental test tank 2, an information processing device 3, an LCD drive device 4, an operation section 5, a light source 6, and a luminance meter 7.

The environmental test tank 2 has a transparent glass window 11 on the front surface.
Is fitted inside, and the LCD under test 2
0 is installed, and a glass fiber cable 12 that guides the irradiation light of the light source 6 from the light source box 6a in which the light source 6 is housed to the vicinity of the LCD 20 under test inside the environmental test tank 2 is attached.

Further, the environmental test tank 2 is provided with a control connector 13 for connecting a control cable to which an environmental control signal for controlling the test environment in the tank is inputted, and the control connected to the control connector 13 is provided. The environmental temperature and the like in the tank are set by the environmental control signal input from the information processing device 3 via the cable.

Further, a liquid crystal temperature detection sensor 14 for directly detecting the liquid crystal temperature is attached to the LCD under test 20, and a liquid crystal drive signal, a liquid crystal temperature detection signal and the like are exchanged with the information processing device 3. Flat cable 15
Is attached. The liquid crystal temperature detection signal detected by the liquid crystal temperature detection sensor 14 is output to the interface circuit 3a in the information processing device 3 via the flat cable 15 and the interface circuit 3a.
A liquid crystal drive signal is input from the LCD drive device 4 via the. The information processing device 3 includes interface circuits 3a and C.
The PU 3b, the hard disk device 3c, the printer 3d, and the XY plotter 3e are included.

The interface circuit 3a has a built-in A / D conversion circuit, a D / A conversion circuit, a voltage level conversion circuit, and the like, and a control connector 13 provided in the external environmental test tank 2.
And a liquid crystal display cell 20 under test via a flat cable 15.

Further, the interface circuit 3a A / D converts the liquid crystal temperature detection signal input from the liquid crystal temperature detection sensor 14 attached to the liquid crystal display cell 20 under test and the luminance measurement signal input from the luminance meter 7. Then CPU3b
D / A the environment setting data for setting the test environment in the environmental test tank 2 that is output from the CPU 3b
Convert and output the environment setting signal to the environment test tank 2 and LCD
The liquid crystal drive signal input from the drive unit 4 is converted into a predetermined voltage level and output to the liquid crystal display cell 20 under test.

CPU (Central Processing Unit) 3b
Has a function as a test environment setting means and an information processing means, has a function of controlling the temperature inside the environmental test tank 2 according to the environmental test tank control program stored in the hard disk device 3c, and relates to the LCD. It has a function of executing various characteristic tests such as a response speed measurement test of the liquid crystal display cell 20 under test installed in the environmental test tank 2 in accordance with the characteristic test program.

That is, the CPU 3b sets data for changing the control pattern of various gradation control methods set in the liquid crystal drive control signal for controlling the gradation of the liquid crystal display cell 20 under test in the response speed measurement test. , To output to the liquid crystal drive control unit 4d in the LCD driving device 4 via the interface circuit 3a, generate an environmental temperature setting signal for setting the environmental temperature in the environmental test tank 2, and perform the environmental test via the interface circuit 3a. The environment temperature setting process is controlled in order to output to the tank 2 and change the environment temperature to obtain a desired test environment temperature for the liquid crystal display cell 20 under test.

Further, the CPU 3b has a function of executing a process of outputting a response speed measurement result report of the liquid crystal display cell 20 under test, a characteristic graph and the like according to a measurement data management program stored in the hard disk device 3c. That is, the response speed measurement result report is created based on the digital liquid crystal temperature detection signal and the brightness measurement signal input from the interface circuit 3a, and the printer 3
In order to print out the characteristic graph of the liquid crystal display cell 20 under test from the XY plotter 3e, the liquid crystal temperature measurement data and the brightness measurement data are generated and output to the XY plotter 3e. .

The hard disk device 3c stores an environmental test tank control program executed by the CPU 3b, a response speed test program, a measurement data management program, and various databases relating to the LCD.

The printer 3c prints out the response speed measurement result report and the like input from the CPU 3b. X-
The Y-plotter 3e records and outputs the in-tank temperature measurement data, the liquid crystal temperature measurement data, and the brightness measurement data generated and input by the CPU 3b on a predetermined recording sheet.

The LCD drive device 4 is composed of a test pattern generation section 4a, an A / D conversion section 4b, a gradation control section 4c, a liquid crystal drive control section 4d and a selection section 4e, and functions as a liquid crystal drive means. Have.

The test pattern generating section 4a has a function of generating a test pattern signal for causing the liquid crystal display cell 20 to be tested to perform a specific display, and converts the test pattern signal into the A / D converting section 4b and the liquid crystal drive control. It is output to the unit 4d.

The A / D conversion section 4b performs A / D conversion on the test pattern signal input from the test pattern generation section 4a and outputs it as test pattern data to the gradation control section 4c. The gradation control unit 4c has a function of generating gradation signals of a plurality of types and a plurality of types, and has test pattern data input from the A / D conversion unit 4b and the liquid crystal drive control unit 4c.
A gradation control signal is generated based on the display drive control signal input from d and output to the selection unit 4e.

The liquid crystal drive control section 4d has a function of generating a basic clock signal and a display drive control signal necessary for display drive, and a control function of exchanging data with the interface circuit 3a in the information processing device 3. The generated basic clock signal is output to the A / D conversion unit 4b and the selection unit 4e, and the generated display drive control signal is output to the gradation control unit 4c.

The selection unit 4e selects one of the grayscale control signal input from the grayscale control unit 4c and the basic clock signal input from the liquid crystal drive control unit 4d to select the information processing device 3
It is output to the internal interface circuit 3a.

The operation section 5 has a selection operation key for selecting a gradation control signal, and outputs a selection instruction signal by a key input operation of the selection operation key to the liquid crystal drive control section 4d and the selection section 4e.

The light source 6 is composed of a halogen light and is housed in the light source box 6a, and the amount of emitted light is adjusted by a variable power source or the like (not shown). Since the light emitted from the light source 6 is used as a backlight for the liquid crystal display cell 20 under test, the light source box 6a and the rear side of the liquid crystal display cell 20 under test installed in the environmental test tank 2 are illustrated. A glass fiber cable 12 is attached to the. The glass fiber cable 12 is held by, for example, a predetermined jig (not shown).

In this embodiment, the liquid crystal display cell 20 to be tested is of the light transmission type, but it may be configured to irradiate light from the front side. Further, the irradiation port of the light source 6 may be irradiated from the outside of the environmental test tank 2 toward the liquid crystal display cell 20 under test through the transparent glass window 11.
Further, as the type of the light source 6, other than this, a laser device may be used, or a tungsten light or the like may be used.

The luminance meter 7 detects the luminance of a specific segment of the liquid crystal display cell 20 under test through the transparent glass window 11 and converts it into a predetermined luminance measurement signal for the interface circuit 3a in the information processing device 3. Output. Further, the luminance meter 7 is provided with a noise filter and an amplification circuit for amplifying a weak luminance detection signal.

Further, in the present embodiment, the cable between the luminance meter 7 and the interface circuit 3a, which is as short as possible and is provided with a noise countermeasure, is used. For example, an optical cable or a coaxial cable is used.

Next, the operation will be described. First, in the liquid crystal test apparatus 1 of the present embodiment, in the case of performing the response speed measurement test of the liquid crystal display cell 20 under test installed in the environmental test tank 2, the test pattern example of the liquid crystal drive signal of FIGS. Will be described with reference to the drawing.

FIG. 2 shows an example in which the gradation control test pattern is changed by the method of controlling the pulse width of the liquid crystal drive signal. In the case of FIG. 2, the change pattern of the pulse width of the liquid crystal drive control signal for performing the gradation control output from the LCD drive device 4 to the liquid crystal display cell 20 under test via the interface circuit 3a is previously set to the information processing device. It is set by the data output from the CPU 3b in the LCD 3 to the liquid crystal drive control unit 4d.

First, the test No. In 11, the first
The measurement results of the response output of the luminance measurement signal by the luminance meter 7 when all the gradation drive patterns from the frame to the fourth frame are set to 24 gradations are shown.

Further, the test No. shown in the figure. In twelve, the first
With the luminance meter 7 when the gradation drive pattern of the frame is set to 22 gradations, the gradation drive pattern of the second frame is set to 23 gradations, and each gradation drive pattern of the third and fourth frames is set to 24 gradations. The measurement result of the response output of the luminance measurement signal is shown.

Furthermore, the test No. shown in the figure. In No. 13, the gradation drive pattern of the first frame is set to 20 gradations, the gradation drive pattern of the second frame is set to 21 gradations, the gradation drive pattern of the third frame is set to 22 gradations, and each floor of the fourth frame is set. The measurement result of the response output of the luminance measurement signal by the luminance meter 7 when the gradation drive pattern is set to 24 gradations is shown.

These test No. Based on the measurement results of the response outputs 11 to 13, the criteria for evaluating the response speed are the reference time Trn (msec) for reaching a certain brightness level at the rising edge and the reference time for reaching a certain brightness level at the falling edge. Time Tfn (msec).

Here, FIG. 5 shows the definition contents for measuring the time Tr until reaching a certain luminance level at the rising edge and the time Tf until reaching a certain luminance level at the falling edge. In this figure, the measurement time Tr at the time of rising is a value until it reaches 90% of the maximum value V0 of the voltage level by the luminance measurement signal, and the measurement time Tf at the time of falling reaches 10% of V0. It is a value.

Test No. In the case of 11, the response time Tr11 at the time of rising is smaller than the reference time Trn, that is, "Tr11 <Trn", and the response time Tf11 at the time of falling is smaller than the reference time Tfn, that is, "T
f11 <Tfn .. When such a response time measurement result is obtained, both the response time Tr11 at the time of rising and the response time Tf11 at the time of falling are too early, and particularly the response time Tr11 at the time of rising. Is steep, an overshoot occurs, which causes flickering display and the like. Therefore, an optimum response speed is not obtained with this gradation control pattern.

Test No. In the case of 12, the response time Tr12 at the time of rising is smaller than the reference time Trn, that is, "Tr12 <Trn", and the response time Tf12 at the time of falling is smaller than the reference time Tfn, that is, "T
f12 <Tfn .. When such response time measurement results are obtained, both the response time Tr12 at the rising edge and the response time Tf12 at the falling edge are fast, but test No. 1
In the case of 1, the steepness is not as steep as that in the case of 1, and the overshoot does not occur, so that it does not cause the flicker display and the like, and the optimum response speed is obtained in this gradation control pattern.

Test No. In the case of 13, the response time Tr13 at the time of rising is larger than the reference time Trn, that is, "Tr13>Trn", and the response time Tf13 at the time of falling is larger than the reference time Tfn, that is, "T
f13> Tfn ”. When such response time measurement results are obtained, both the response time Tr13 at the rising edge and the response time Tf13 at the falling edge are too slow, and the optimum response speed is obtained. Not not.

FIG. 3 shows an example in which the gradation control test pattern is changed by the method of controlling the voltage of the liquid crystal drive signal. In the case of FIG. 3, the change pattern of the voltage of the liquid crystal drive control signal for performing the gradation control output from the LCD drive device 4 to the liquid crystal display cell 20 under test via the interface circuit 3a is the information processing device 3 in advance. CPU3 in
It is set by the data output from b to the liquid crystal drive control unit 4d.

First, the test No. shown in FIG. At 21, the first
The measurement result of the response output of the luminance measurement signal by the luminance meter 7 when the voltage value of each gradation control signal from the frame to the fourth frame is set to "10 volts (effective value)" is shown.

Further, the test No. shown in the figure. At 22, first
The voltage value of the gradation control signal of the frame is set to "8 volts (effective value)", the voltage value of the gradation control signal of the second frame is set to "9 volts (effective value)", and each floor of the third and fourth frames is set. The measurement result of the response output of the luminance measurement signal by the luminance meter 7 when the voltage value of the adjustment control signal is set to "10 volts (effective value)" is shown.

Further, the test No. shown in the figure. In No. 23, the voltage value of the gradation control signal of the first frame is set to “7 volts (effective value)”, the voltage value of the gradation control signal of the second frame is set to “8 volts (effective value)”, and the third frame is set. Luminance measurement by the luminance meter 7 when the voltage value of the gradation control signal of is set to "9 volts (effective value)" and the voltage value of each gradation control signal of the fourth frame is set to "10 volts (effective value)" The measurement result of the signal response output is shown.

These test No. Based on the measurement results of the response outputs 21 to 23, the criteria for evaluating the response speed are the reference time Trn (msec) required to reach a certain luminance level at the rising edge and the reference time to reach a certain luminance level at the falling edge. Time Tfn (msec).

Test No. In the case of 21, the response time Tr21 at the rising time is smaller than the reference time Trn, that is, "Tr21 <Trn", and the response time Tf21 at the falling time is smaller than the reference time Tfn, that is, "T
f21 <Tfn .. When such a response time measurement result is obtained, both the response time Tr21 at the time of rising and the response time Tf21 at the time of falling are too early, and particularly the response time Tr21 at the time of rising. Is steep, an overshoot occurs, which causes flickering display and the like. Therefore, an optimum response speed is not obtained with this gradation control pattern.

Test No. In the case of 22, the response time Tr22 at the rising time is smaller than the reference time Trn, that is, "Tr22 <Trn", and the response time Tf22 at the falling time is smaller than the reference time Tfn, that is, "T
f22 <Tfn .. When such a response time measurement result is obtained, both the response time Tr22 at the time of rising and the response time Tf22 at the time of falling are early, but test No. 2
In the case of 1, the steepness is not as steep as that in the case of 1, and the overshoot does not occur, so that it does not cause the flicker display and the like, and the optimum response speed is obtained in this gradation control pattern.

Test No. In the case of 23, the response time Tr23 at the rising time is larger than the reference time Trn, that is, "Tr23>Trn", and the response time Tf23 at the falling time is larger than the reference time Tfn, that is, "T
f23> Tfn ”. When such response time measurement results are obtained, both the response time Tr23 at the rising edge and the response time Tf23 at the falling edge are too slow, and the optimum response speed is obtained. Not not.

FIG. 4 shows an example in which the gradation control test pattern is changed by the method of thinning out the frames of the liquid crystal drive signal. In the case of FIG. 4, the LCD driving device 4
From the CPU 3b in the information processing device 3 to the liquid crystal drive control section 4d in advance, the frame thinning pattern of the liquid crystal drive control signal for performing the gradation control, which is output to the liquid crystal display cell 20 under test from the interface circuit 3a. It is set by the data. First, the test No. In No. 31, the luminance measurement signal of the luminance meter 7 when the gradation number of each frame is set to 24 gradations by setting "0" without thinning out each gradation control signal from the first frame to the fourth frame The measurement result of the response output is shown.

Further, the test No. At 32, the first
The gradation control signal of the frame is subtracted by 2 gradations and set to 22 gradations, and the gradation control signal of the 2nd frame is subtracted by 1 gradation and set to 23 gradations. Each of the gradation control signals of No. 2 shows the measurement result of the response output of the brightness measurement signal by the brightness meter 7 when the gradation is set to 24 gradations without thinning out.

Further, the test No. shown in the figure. In 33, the gradation control signal of the first frame is subtracted by 4 gradations and set to 20 gradations, and the gradation control signal of the second frame is subtracted by 3 gradations and set to 22 gradations. Luminance measurement signal by the luminance meter 7 when the gradation control signals of 3 frames are subtracted by 2 gradations and set to 22 gradations, and the gradation control signals of the 4th frame are set to 24 gradations without being thinned out. The measurement result of the response output of is shown.

These test No. Based on the measurement results of the response outputs 31 to 33, the criteria for evaluating the response speed are the reference time Trn (msec) until reaching a certain brightness level at the rising edge and the reference time until reaching a certain brightness level at the falling edge. Time Tfn (msec).

Test No. In the case of 31, the response time Tr31 at the time of rising is smaller than the reference time Trn, that is, "Tr31 <Trn", and the response time Tf31 at the time of falling is smaller than the reference time Tfn, that is, "T
f31 <Tfn .. When such a response time measurement result is obtained, both the response time Tr21 at the time of rising and the response time Tf31 at the time of falling are too early, and particularly the response time Tr31 at the time of rising. Is steep, an overshoot occurs, which causes flickering display and the like. Therefore, an optimum response speed is not obtained with this gradation control pattern.

Test No. In the case of 32, the response time Tr32 at the rising time is smaller than the reference time Trn, that is, "Tr32 <Trn", and the response time Tf32 at the falling time is smaller than the reference time Tfn, that is, "T
f32 <Tfn .. When such a response time measurement result is obtained, both the rise response time Tr32 and the fall response time Tf32 are fast, but test No. 3
In the case of 1, the steepness is not as steep as that in the case of 1, and the overshoot does not occur, so that it does not cause the flicker display and the like, and the optimum response speed is obtained in this gradation control pattern.

Test No. In the case of 33, the response time Tr33 at the time of rising is longer than the reference time Trn, that is, "Tr33>Trn", and the response time Tf33 at the time of falling is larger than the reference time Tfn, that is, "T
f33> Tfn ”. When such response time measurement results are obtained, both the response time Tr33 at the rising edge and the response time Tf33 at the falling edge are too slow, so the optimum response speed is obtained. Not not.

The measurement result of the response speed by each of the above control methods is measured by the CPU 3b in the information processing device 3, and the response speed is measured based on the liquid crystal temperature detection data and the brightness measurement data input from the interface circuit 3a. The result report is created and printed out from the printer 3d, and the liquid crystal display cell 20
The response speed characteristic graph of is recorded and output from the XY plotter 3e.

As described above, the liquid crystal test apparatus 1 of this embodiment
Then, the information processing apparatus 3 and the LC having the test environment setting function of the liquid crystal display cell 20 under test installed in the environment test tank 2 and the setting method of the control method of the liquid crystal drive signal for performing the gradation control are described.
Since the D driving device 4 is provided, it is possible to easily find the optimum gradation driving method for the liquid crystal display cell 20 under test, and as a result, it is possible to obtain stable display quality without flicker.

Further, the luminance meter 7 and the liquid crystal temperature detecting sensor 14
Since it is possible to process the data detected by these sensors in the information processing device 3 and extract the characteristic data that can be evaluated, the characteristic test can be rationalized and processed in a short time.

As a combination method of the gradation control method when evaluating the response characteristics, for example, in the gradation drive range shown in the response characteristic graph of FIG. Repeat.

Bright level → dark level Dark level → bright level Bright level → halftone level Dark level → halftone level Midtone level → bright level Midtone level → dark level Then, the time until reaching a certain brightness level at the time of rising. It is possible to find the gradation control pattern that comes closest to Tr and the time Tf required to reach a certain brightness level at the fall.

Further, since the information processing device 3 has a function of setting the environmental temperature in the environmental test tank 2, the environmental temperature of the liquid crystal display cell 20 under test can be easily controlled. Further, by mounting the liquid crystal temperature detection sensor 14 that directly detects the temperature of the liquid crystal display cell 20 under test, it is possible to reduce the temperature measurement error as compared with the conventional ambient temperature measurement.

Further, in the information processing device 3, the characteristic test program is stored in advance and the test processing of the liquid crystal display cell 20 under test is automatically executed in sequence, so that the test work is smoothly carried out and the test operation is simple. A flexible test can be performed by changing the program, and the work load on the person in charge of testing can be greatly reduced.

Next, FIG. 6 shows an embodiment in which a judgment circuit for judging the response speed measurement result of the liquid crystal display cell 20 under test is provided in the interface circuit 3a of the information processing apparatus 3.

In FIG. 6, an A / D conversion circuit 31, an amplification circuit 32, a level converter 33 and a determination circuit 34 are provided in the interface circuit 3a. A /
The D conversion circuit 31 has a function of converting a liquid crystal temperature detection signal input from the liquid crystal temperature detection sensor 14 into digital data that can be processed by the CPU 3b and outputting the digital data to the CPU 3b.

The amplifier circuit 32 amplifies the brightness measurement signal input from the brightness meter 7 with a predetermined amplification factor and outputs it to the level converter 3.
3, and the level converter 33 converts the voltage level of the brightness measurement signal input from the amplifier circuit 32 and outputs the voltage level to the determination circuit 34.

The determination circuit 34 performs overshoot determination processing based on the brightness measurement signal in which the voltage level input from the level converter 33 is converted, and outputs the determination result to the CPU 3b.

A concrete example of the overshoot determination processing of the luminance measurement signal in the determination circuit 34 will be described with reference to FIGS. 7 and 8. FIG. 7 is a diagram showing sampling timings of the liquid crystal drive signal and the luminance meter output signal. In FIG. 7, (a) is the drive timing of the liquid crystal drive signal per frame, (b) is the sampling timing for sampling the luminance measurement signal, and (c) is the output signal of the luminance meter 7 (luminance measurement signal). ), And (d) is sampling data obtained by sampling the output of (c) with the sampling timing of (b).

In the judgment circuit 34, after the luminance measurement signal is sampled based on the sampling pulse shown in FIG. 7, as shown in FIG. 7D, one sampling data interval Δt≈1.5 msec is set to 3 seconds / It is expanded to 2,048 bits, and the voltage level of each sampling data is further divided into 5V / 64 dots to determine overshoot.

For example, as shown in FIG. 8, the voltage levels v1 to v5 of the luminance measurement signal output from the level converter 33 are compared with each other at the measurement timings t1 to t5. In this case, the result of the mutual comparison is "v1 <v2, v2
<V3, v3> v4, v4> v5 ", and the presence or absence of overshoot is determined by determining the voltage at the minimum point v1 and the maximum point v3 from the comparison result.

When the overshoot determination result by the determination circuit 34 is output to the CPU 3b, the CPU 3b determines the liquid crystal drive control condition based on the setting of the gradation control pattern in which the overshoot does not occur, and the determination result is The measurement result report is output from the 3d or the XY plotter 3e.

As described above, the interface circuit 3a
A determination circuit 34 is provided in the interior of the printer 3d or the XY plotter 3 to automatically determine the presence or absence of overshoot during speed response by luminance measurement.
By displaying it in the measurement result report output from e, the tester can save the trouble of evaluating and determining the pattern in which the optimum response speed can be obtained from each pattern of the gradation control method set in the liquid crystal drive signal. Therefore, it is possible to further reduce the work load on the person in charge of testing.

The gradation control method that provides the optimum response speed can be easily selected by the above-described response characteristic determination processing. As a result, as shown in the response characteristic graph of FIG.
For the liquid crystal display cell 20 under test, the gradation drive range is defined as the response time Tr1 in the case of performing from the halftone brightness level to the bright level, and the response time Tr1 in the case of performing from the dark level brightness to the bright level brightness Tr1. The liquid crystal drive signal that realizes the gradation control can be easily determined.

Further, the above judgment result can be used for standardization of quality control of the liquid crystal display cell, the optimum response characteristic of the liquid crystal display cell can be automatically judged, and the use range of the liquid crystal test apparatus 1 can be determined. Can be expanded.

[0087]

According to the first aspect of the present invention, the liquid crystal test apparatus has a liquid crystal drive signal control method for performing a test environment setting function and gradation control of a liquid crystal display cell under test installed in an environmental test tank. By providing the information processing device having the setting function and the liquid crystal driving device, it is possible to easily find the optimum gradation driving method for the liquid crystal display cell under test, and as a result, a stable display without flickering in the liquid crystal display device. You can get quality.

According to the second aspect of the invention, the characteristic test of the liquid crystal can be rationalized and processed in a short time, and the temperature measurement error can be reduced as compared with the conventional ambient temperature measurement.

According to the third aspect of the invention, the environmental temperature of the liquid crystal display cell under test can be easily controlled.

According to the invention described in claim 4, the test work can be performed smoothly, and the flexible test can be performed by a simple program change, and the work load on the person in charge of the test work can be greatly reduced. can do.

According to the fifth aspect of the invention, the optimum response characteristic of the liquid crystal display cell can be easily determined, and the determination result can be used for standardization of quality control of the liquid crystal display cell. .

According to the sixth aspect of the invention, the optimum response characteristic of the liquid crystal display cell can be automatically determined, and each pattern of the gradation control method set by the person in charge of the test operation in the liquid crystal drive signal. Therefore, it is possible to omit the trouble of evaluating and determining the pattern that can obtain the optimum response speed, and it is possible to further reduce the work load on the person in charge of the test work. Further, by selecting a gradation control method, it is possible to easily respond to a response characteristic test of a new liquid crystal display cell, and it is possible to expand the range of use of the liquid crystal test device.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of a liquid crystal test apparatus of the present invention.

FIG. 2 is a diagram showing an example in which a gradation control test pattern is changed by a method of controlling a pulse width of a liquid crystal drive signal.

FIG. 3 is a diagram showing an example in which a gradation control test pattern is changed by a method of controlling a voltage of a liquid crystal drive signal.

FIG. 4 is a diagram showing an example in which a gradation control test pattern is changed by a method of thinning out a frame of a liquid crystal drive signal.

FIG. 5 is a diagram showing the definition contents when measuring a time Tr until reaching a certain brightness level at the time of rising and a time Tf until reaching a certain brightness level at the time of falling.

FIG. 6 is a block configuration diagram of an embodiment in which a determination circuit for overshoot determination is added to the interface circuit of FIG.

7 is a diagram showing a sampling process of a luminance measurement signal sampled by the determination circuit of FIG.

8 is a diagram showing an example of voltage level data of a luminance measurement signal subjected to mutual comparison processing by the determination circuit of FIG.

FIG. 9 is a graph showing ideal rising response characteristics obtained by giving optimum grayscale driving conditions.

FIG. 10 is a diagram showing an example of a response characteristic graph obtained by a conventional liquid crystal test apparatus.

[Explanation of reference numerals] 1 liquid crystal test device 2 environment test tank 3 information processing device 3a interface circuit 3b CPU 3c hard disk device 3d printer 3e XY plotter 4 LCD drive device 4a test pattern generation unit 4b A / D conversion unit 4c gradation Control unit 4d Liquid crystal drive control unit 4e Selection unit 5 Operation unit 6 Light source 6a Light source box 7 Luminance meter 11 Transparent glass window 12 Glass fiber cable 13 Control connector 14 Liquid crystal temperature detection sensor 15 Flat cable 31 A / D conversion circuit 32 Amplification circuit 33 Level converter 34 Judgment circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G09G 3/18

Claims (6)

[Claims] 1. A light source for irradiating light to a liquid crystal display cell under test installed in a predetermined tank, and a liquid crystal driving means for generating a liquid crystal drive signal for gradation driving of the liquid crystal display cell under test. A test environment setting means for setting various test environments in the tank; a brightness detecting means for detecting a brightness level of transmitted light or reflected light of light emitted from the light source to the liquid crystal display cell under test; Information processing for controlling the gradation driving pattern set by the liquid crystal driving signal generated by the driving means, and information processing for controlling the setting condition of the test environment set by the test environment setting means A liquid crystal test apparatus comprising: 2. A liquid crystal temperature detecting means for directly detecting the temperature of the liquid crystal display cell under test is provided, and the information processing means responds to gradation drive pattern control and test environment setting condition control. Based on the brightness detected by the brightness detection means and the temperature of the liquid crystal display cell under test detected by the liquid crystal temperature detection means, the response characteristics of the liquid crystal display cell under test in various test environments are evaluated. The liquid crystal test apparatus according to claim 1, wherein information processing for performing the information processing is performed. 3. The liquid crystal test apparatus according to claim 1, wherein the information processing means controls a set temperature for setting the environmental temperature in the tank by the environment setting means. 4. The information processing means has a storage means for storing a test program for executing the pattern control of the gradation driving and the control of the test environment, and the liquid crystal under test is based on the test program. 2. The liquid crystal test apparatus according to claim 1, wherein the response speed evaluation test of the display cells is sequentially executed. 5. The information processing means, when performing information processing for evaluating the response characteristic of the liquid crystal display cell under test, changes in the brightness level detected by the brightness detecting means indicating the response characteristic. 5. The liquid crystal test apparatus according to claim 1, wherein sampling is performed at predetermined time intervals, and the sampled data is compared and judged with a predetermined reference value. 6. The information processing means is a first reference serving as a reference in advance.
And a plurality of sets of second brightness level data different from the first brightness level data are stored, and when performing information processing for evaluating the response characteristics of the liquid crystal display cell under test, The liquid crystal driving means measures a plurality of response times until the luminance level detected by the luminance detecting means reaches the second luminance level from the first luminance level, and the difference between the respective response times is minimized. The liquid crystal test apparatus according to claim 1 or 2, wherein the liquid crystal drive signal generated by the method is controlled.