JPH1068672A - Liquid crystal evaluation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and efficiently perform measurement of a liquid crystal pitch and permeability/voltage characteristics by minutely moving upper and lower liquid crystal boards opposing one another with a minute clearance in substantially parallel and changing the minute clearance. SOLUTION: At first, voltage is applied to piezoelectric actuators 38, 41, a minute moving stage 20 is set in an initial parallel state and upper side and lower side liquid crystal boards 2, 3 are made parallel. Next, the minute moving stage 20 is moved in the direction of a y-axis in parallel while application voltage of the actuators 38, 41 is gradually changed and a minute movement of the minute moving stage 20 is monitored with displacement gages 42, 43. The luminance level of transmission light of a minute area on the upper side liquid crystal board 2 is measured with a CCD camera 65, and a liquid crystal pitch is obtained from the position of the minute moving stage 20 corresponding to the maximum value and minimum value. In addition, a switch 58 is conducted, direct current voltage of a power source 57 is gradually increased to measure the luminance of the minute specified area on the upper side liquid crystal board 2, and permeability/voltage characteristics can be obtained from the application voltage and the luminance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal evaluation device for evaluating characteristics of a liquid crystal material, and is useful when applied to a case where a liquid crystal pitch and a transmittance / voltage characteristic are measured.

[0002]

2. Description of the Related Art Conventionally, there is measurement of a liquid crystal pitch as an evaluation item of a liquid crystal material. The liquid crystal pitch is specific to a liquid crystal material, and is a distance required for a liquid crystal molecular chain to be twisted by 360 °.

A liquid crystal material manufacturer measures a liquid crystal pitch in the research and development, quality control and shipping inspection of a liquid crystal material.

[0004] Liquid crystal display device manufacturers not only measure the pitch of the liquid crystal in the acceptance inspection of the liquid crystal material, but also mix and select from more than 15,000 types of liquid crystal materials that are practically used. Research and development are being carried out to improve the liquid crystal display performance by changing the type of liquid crystal material used and the mixing ratio, and in the process, measurement of the liquid crystal pitch of the mixed liquid crystal material is indispensable.

Conventionally, the measurement of the liquid crystal pitch has been performed using a wedge type cell 1 as shown in FIG. As shown in FIG. 1, the wedge-type cell 1 is configured such that an upper liquid crystal substrate 2 and a lower liquid crystal substrate 3 are inclined and overlapped with a spacer 4 interposed therebetween.
The left and right ends are fixed with adhesives 5 and 6, and liquid crystal molecules 8 are made to penetrate into minute gaps 7 between the upper liquid crystal substrate 2 and the lower liquid crystal substrate 3. The upper liquid crystal substrate 2
The lower liquid crystal substrate 3 is a laminated plate formed by laminating an alignment film 12, a glass plate 13, and a polarizing plate 14. The polarizing plate 9, the glass plate 10, and the alignment film 11 are laminated. ing. The alignment films 11 and 12 have a function of forcing the posture of the end portions of the liquid crystal molecular chains 8 and the like. Also, for convenience of explanation,
It is assumed that the polarization directions of the polarizing plates 9 and 14 match.

Accordingly, when the wedge-type cell 1 is irradiated with white light 15 from the back surface (the lower liquid crystal substrate 3 side), and the upper liquid crystal substrate 2 is viewed from the direction A as shown in FIG. As shown in FIG. 3B, discrimination lines 16, 17, and 18 appearing as black lines at regular intervals are observed. These discrimination lines 16, 1
The reasons for the occurrence of 7 and 18 are as follows.

That is, since the polarization directions of the polarizers 9 and 14 match, the transmittance of the white light 15 passing through the wedge-type cell 1 is equal to the case where the twist angle of the liquid crystal molecular chain 8 is an even multiple of 90 °. On the other hand, when the twist angle of the liquid crystal molecular chain 8 is an odd multiple of 90 °, it becomes the minimum, and the discrimination lines 16, 17, and 18 correspond to the latter case.

When the distance L between the discrimination lines 16, 17, and 18 is measured by image processing or other measuring means, the upper liquid crystal substrate 2 of the wedge cell 1 is measured.
The liquid crystal pitch P is calculated by the following first formula given the inclination angle (wedge angle) と formed between the liquid crystal and the lower liquid crystal substrate 3. P = 2LtanΘ (1)

After obtaining the liquid crystal pitch P by the above equation, the liquid crystal display device maker arranges the upper and lower liquid crystal substrates 2 and 3 shown in FIG. 7 in parallel, and places a micro plastic ball and a liquid crystal material in these gaps. Are mixed and filled, the diameter of the microplastic ball is selected as a set gap, and four sides of the liquid crystal substrates 2 and 3 are bonded to produce a flat cell (not shown), and the flat cell is used by using the flat cell. Evaluation of transmittance / voltage characteristics (details will be described later) and the like, that is, responsiveness at the time of lighting ON / OFF, contrast ratio, viewing angle, and the like are evaluated. At this time, the upper liquid crystal substrate 2 and the lower liquid crystal in the flat cell are evaluated. The liquid crystal sealing gap (cell gap) with the substrate 3 is based on the result of the liquid crystal pitch measurement. Therefore, the accuracy of the liquid crystal pitch measurement has a significant effect on the reliability of the liquid crystal display performance evaluation test.

[0010]

However, in the conventional liquid crystal pitch measuring method using the wedge type cell 1 described above,
There are a number of inconveniences as follows, and therefore, there are many problems in terms of work efficiency and reliability of evaluation.

(1) Preparation for measurement takes time and effort. That is, the assembly and bonding of the wedge-type cell 1 are manual and time-consuming.

(2) There are many factors that deteriorate the measurement accuracy of the liquid crystal pitch. For example, the mounting position error of the spacer 4 in the wedge-type cell 1 of FIG.
As can be seen from the equation, a calculation error of the liquid crystal pitch P occurs.
Generally, the glass plates 10 and 13 are warped, which also causes an error. In particular, since the liquid crystal pitch is small in the STN liquid crystal, the method using the conventional wedge-type cell 1
It is difficult to measure the liquid crystal pitch with high accuracy.

(3) The reliability of the liquid crystal display performance evaluation such as the response at the time of lighting ON / OFF, the contrast ratio, and the viewing angle is reduced. That is, since the liquid crystal enclosing gap (cell gap) is determined based on the measurement result of the liquid crystal pitch, if the accuracy of the measurement of the liquid crystal pitch is poor as described above, the setting of the cell gap becomes inappropriate. The reliability of the display performance evaluation test itself decreases.

(4) Since the measurement of the liquid crystal pitch and the measurement of the transmittance / voltage characteristics are performed by separate devices (wedge-type cell and flat-type cell), both measurements are performed in different steps, resulting in poor work efficiency.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a liquid crystal evaluation device capable of accurately and efficiently measuring a liquid crystal pitch and a transmittance / voltage characteristic in view of the above prior art.

[0016]

According to a first aspect of the present invention, there is provided a liquid crystal evaluation apparatus for solving the above-mentioned problems, comprising first and second liquid crystal substrates facing each other with a minute gap for accommodating a liquid crystal material to be evaluated. Translation means for finely moving the first or second liquid crystal substrate substantially in parallel to change the minute gap;
The first means, which is slightly moved substantially in parallel by the moving means,
Or a movement amount measuring means for measuring a movement amount of the second liquid crystal substrate, a light source for irradiating light from the first or second liquid crystal substrate side, and the light source irradiating the light source with the light source. A luminance measuring means for measuring the luminance of a minute specific area of the second or first liquid crystal substrate.

According to a second configuration, in the first configuration, a tilting means for tilting the first or second liquid crystal substrate, and the first or second liquid crystal substrate is tilted by the tilting means. Angle measuring means for measuring the angle of inclination between the first liquid crystal substrate and the second liquid crystal substrate caused by the first and second liquid crystal substrates, and the second or first liquid crystal substrate on the side opposite to the light irradiation side of the light source. And an interval measuring means for measuring an interval between the generated discrimination lines.

According to a third aspect, in the first or second aspect, voltage applying means for applying a variable DC voltage to the transparent electrodes of the first liquid crystal substrate and the second liquid crystal substrate is provided. It is characterized by.

Therefore, according to the liquid crystal evaluation device having the first configuration, the light source irradiates light from the first or second liquid crystal substrate side and the first or second liquid crystal substrate is moved in substantially parallel by the parallel moving means. Then, the movement amount of the first or second liquid crystal substrate and the luminance of the minute specific area of the second or first liquid crystal substrate at this time are measured by the movement amount measuring means and the luminance measuring means, respectively. Then, a high-precision liquid crystal in which the warpage and thickness variation of the liquid crystal substrate are removed from the interval between the maximum value (or the minimum value) of the luminance (transmittance) obtained as a result. The pitch can be determined.

Further, according to the liquid crystal evaluation apparatus of the second configuration, before measuring the liquid crystal pitch with high accuracy as described above, an approximate value of the liquid crystal pitch is obtained in advance, and based on this approximate value, High precision measurement of the liquid crystal pitch can be performed efficiently. The procedure will be described below.

The first or second liquid crystal substrate is tilted by tilting means to give an inclination angle Θ to these liquid crystal substrates, and light is irradiated from the first or second liquid crystal substrate side by a light source. The distance L between the discrimination lines occurring on the second or first liquid crystal substrate is measured by the distance measuring means. Then, the interval L and the inclination angle Θ
From, to calculate the approximate value P ₁ of the liquid crystal pitch by a second equation below. P ₁ = 2LtanΘ (Formula 2)

Next, after the first liquid crystal substrate and the second liquid crystal substrate are made parallel by the tilting means, the distance between the two liquid crystal substrates is gradually reduced by the parallel moving means. The luminance of the minute specific area of the first liquid crystal substrate is measured by the luminance measuring means. The measurement of the luminance is performed in three stages as follows.

In the first stage, the moving speed of the first or second liquid crystal substrate by the parallel moving means is increased to grasp the approximate position where the luminance level becomes maximum (or minimum). In the second stage, the moving speed of the first or second liquid crystal substrate by the parallel moving means is reduced so that the luminance level is maximum (or minimum).
Know exactly where it will be. In the third stage, based on the data of the approximate value P ₁ of the liquid crystal pitch, after moving only P ₁ by increasing the first or the moving speed of the second liquid crystal substrate by translating means, moves back and forth in this position Move at a reduced speed to accurately grasp the position where the luminance level is maximum (or minimum). The moving distance of the first or second liquid crystal substrate from the position where the luminance level is maximum (or minimum) to the position where it is maximum (or minimum) again, that is, the amount of change in the gap becomes an accurate value of the liquid crystal pitch. .

Further, according to the liquid crystal evaluation device of the third configuration, after the liquid crystal pitch is measured, the same device continues to measure the pitch of the liquid crystal.
The transmittance / voltage characteristics can be measured as follows.

The first or second liquid crystal substrate is moved by the parallel moving means, and is set at a position where the luminance of the minute specific area has a minimum value. A DC voltage (variable) is applied by the voltage applying means, and this voltage value is gradually increased. The luminance of the minute specific area is measured by the luminance measuring means, and the relationship between this luminance (transmittance) and the applied voltage value is obtained.
Obtain transmittance / voltage characteristics. From this transmittance / voltage characteristic, a contrast ratio and the like are obtained.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a liquid crystal evaluation apparatus according to an embodiment of the present invention, FIG. 2 is a view showing the configuration of a liquid crystal substrate provided in the liquid crystal evaluation apparatus shown in FIG. 1, and FIG. 4 and 5 are explanatory diagrams of high-precision measurement of liquid crystal pitch, and FIG. 6 is an explanatory diagram of transmittance / voltage characteristic measurement.

As shown in FIG. 1, the lower liquid crystal substrate 3 and the upper liquid crystal substrate 2 face each other with a small gap δ. The lower liquid crystal substrate 3 is fixed to the fine movement stage 20 by being sucked by the concave portions 23 and 24 evacuated through the exhaust holes 21 and 22. The upper liquid crystal substrate 2
Recess 2 evacuated through exhaust holes 25 and 26
7 and 28, the upper holding member 29
It is fixed to.

Here, referring to FIG.
The structure of No. 3 will be described. FIG. 1 shows the structure of the liquid crystal substrates 2 and 3 in an enlarged and exaggerated manner. As shown in the figure, the upper liquid crystal substrate 2 is a laminated plate formed by laminating a polarizing plate 9, a glass plate 10, a transparent electrode film 55 and an alignment film 11, and the lower liquid crystal substrate 3 is formed of an alignment film. 12. Glass plate 1
3. A laminated plate in which the transparent electrode film 56 and the polarizing plate 14 are laminated. Here, for convenience of explanation, the polarization directions of the polarizing plates 9 and 14 are assumed to be the same, and the alignment films 11 and 12 are
Are also the same. The small gap δ between the upper liquid crystal substrate 2 and the lower liquid crystal substrate 3 is filled with the liquid crystal material 30 without flowing out due to surface tension. Is composed.

As shown in FIG. 1, fine movement stage 20 has spring portions 32, 33 and 34, which are flexible in the y-axis direction.
35 are provided symmetrically and piezoelectric actuators 38 and 4 are formed by laminating a large number of piezoelectric elements in the y-axis direction.
1 are spring portions 36, 37 and 3 which are flexible in the x-axis direction.
9 and 40, and are symmetrically assembled.

Therefore, when a voltage is applied to both ends of the piezoelectric actuators 38, 41, the fine movement stage 2 is moved through the spring portions 36, 37 or 39, 40 which are flexible in the x-axis direction.
0, the force in the y-axis direction is transmitted, and the spring portion 32, 33 or 34, 35, which is flexible in the y-axis direction, is elastically deformed, so that the fine movement stage 20 (lower liquid crystal substrate 3)
It moves slightly in the vertical direction in parallel or tilts by fine rotation. That is, the piezoelectric actuators 38, 4
When the values of the voltages applied to 1 are equal, they translate in parallel,
Tilt when different. The minute movement amount or the inclination angle of the fine movement stage 20 (the lower liquid crystal substrate 3) is determined by a pair of capacitance type or eddy current type displacement meters 42 symmetrically arranged.
43.

The fine movement stage 20 is set on the base member 44, while the upper holding member 29 is
It is positioned above the base member 44 via 5, 46 and 47, 48. Further, ball bushes 49, 50 are fitted to both left and right end portions of the upper holding member 29, and the base members 4 are attached to the ball bushes 49, 50.
The guide shafts 51 and 52 erected at 4 are slidably inserted in the y-axis direction. Therefore, the upper holding member 29 is driven by an air cylinder (not shown), and the guide shaft 51,
The guide 52 moves up and down in the directions of arrows a and b.

In the through hole at the center of the upper holding member 29,
A glass flange 53 is fitted, and a glass flange 54 is fitted in an upper through hole at the center of fine movement stage 20. The glass flanges 53 and 54 respectively face the lower or upper liquid crystal substrates 2 and 3 with gaps therebetween.
The polarizing plates 9 and 14 installed on the glass plates 10 and 13 shown in FIG. 2A may be installed on the glass flanges 53 and 54, respectively, as shown in FIG. 2B.
Indicates the latter case. The transparent electrodes 55 and 56 of the upper and lower liquid crystal substrates 2 and 3 are connected to electrodes 91 and 92 connected to a DC power supply 57 and a switch 58 via an alignment film at the time of mounting. ing.

The lens 5 is provided below the glass flange 54.
9, an aperture plate 60, a lens 61, and a light source 62 are provided. The light 63 of the light source 62 is transmitted by the lens 61 to the aperture plate 6.
The light is condensed on the zero hole 64. The focal position of lens 59 is hole 6
4 so that the hole 64
Is approximated to a parallel light by the lens 59, passes through the upper and lower liquid crystal substrates 2 and 3, and is received by the CCD camera 65.
The output of the CCD camera 65 is processed by an image processing device 66, and the image processing data is transferred to a personal computer 67.

Next, the method of use and operation of the present liquid crystal evaluation apparatus will be described in (1) preparation for measurement, (2) approximate measurement of liquid crystal pitch,
The description will be made in the order of (3) high-precision measurement of liquid crystal pitch, and (4) measurement of transmittance / voltage characteristics.

(1) Preparation for Measurement Initial state: The upper holding member 29 has been moved in the direction of arrow a and is at the rising end. Setting of test sample: The upper and lower liquid crystal substrates 2 and 3 are set on the upper holding member 29 and the fine movement stage 20.
At this time, the liquid crystal substrates 2 and 3 are sucked by evacuating through the exhaust holes 25, 26, 21 and 22. next,
The liquid crystal material 30 is dropped on the surface of the lower liquid crystal substrate 3. Lamination of liquid crystal substrates: The upper holding member 29 is moved in the direction of arrow b to be a lower end. At this time, the liquid crystal substrates 2,
3 faces at a minute gap (gap) δ, and the liquid crystal material 30 is held by filling the inside of the minute gap δ by the surface tension.

(2) Measurement of Approximate Value of Liquid Crystal Pitch In order to increase the measurement efficiency of “high-precision measurement of liquid crystal pitch” described later, the approximate value of liquid crystal pitch is measured in the following procedure.

Fine rotation of the fine movement stage (tilt): A voltage is applied to one of the piezoelectric actuators 38 and 40, and the fine movement stage 20 is tilted to a small tilt angle Θ. The tilt angle Θ is calculated from the detection values of the displacement meters 42 and 43. Measurement of discrimination line interval: As shown in FIG. 3, since the transmittance is minimized at a position where the twist angle of the liquid crystal molecular chain 68 is an odd multiple of 90 °, the discrimination lines such as 16, 17 are formed. Occur. The distance L between the discrimination lines is determined by the CCD camera 6
The image No. 5 is calculated by subjecting the image No. 5 to gray-scale image processing by the image processing device 66. Approximation P ₁ of the liquid crystal pitch is calculated by the second equation. The inclination angle の on the right side of the second equation includes the warpage of the glass plates 10 and 13 and the initial angle setting error.

(3) High precision measurement of liquid crystal pitch Parallel setting of liquid crystal substrates: piezoelectric actuators 38, 4
1 to return the fine movement stage 20 to the initial parallel state. That is, as shown in FIG. 2, the upper liquid crystal substrate 2 and the lower liquid crystal substrate 3 are made parallel. However, the term “parallel” here is not strictly parallel, but rather the glass plate 1.
It also includes the warpage of 0, 13 and the variation of the thickness, and the initial angle setting error. High-precision parallel movement of the lower liquid crystal substrate: While gradually changing the applied voltage of the piezoelectric actuators 38 and 41 and monitoring the amount of fine movement of the fine movement stage 20 with the displacement meters 42 and 43, the fine movement stage 20 is moved to the right and left with no inequality 0. Translate in the y-axis direction with an accuracy of 1 μm or less. However, the fine movement control of the fine movement stage 20 is performed by a control device (not shown) and the personal computer 67.

Extreme value measurement of the luminance of transmitted light: transmission of the minute specific area S ₁ of the upper liquid crystal substrate 2 shown in FIG. 4 when the lower liquid crystal substrate 3 shown in FIG. 2 is moved in parallel in the y-axis direction. The brightness level of the light is measured by the CCD camera 65 and the image processing device 66. As a result, as shown in FIG. 5, a luminance level that changes with a maximum value and a minimum value according to a change in the minute gap δ between the liquid crystal substrates 2 and 3, that is, a movement amount of the fine movement stage 20, is measured. Liquid crystal pitch measurement: The amount of movement of the fine movement stage 20 between the maximum value and the minimum value or between the minimum value and the minimum value shown in FIG. 5 represents の of the liquid crystal pitch.

The liquid crystal substrate 2 and 3 in the upper small specific area S ₁ of the liquid crystal substrate 2 and the minute specific area S ₂ Metropolitan shown in FIG. 4
Are not always the same due to the warpage of the glass plates 10 and 13 and the initial angle setting error. Therefore, as shown by the solid line and the broken line in FIG. 5, although the phase deviates brightness maximum value in the small specific area S ₁ and the minute specific area S ₂ (minimum value), between the maximum value and the maximum value (or The movement amount of the fine movement stage 20 (between the minimum value and the minimum value) becomes equal. Therefore, when the fine movement stage 20 is translated in the y-axis direction with high accuracy, the brightness of the specific minute area of the upper liquid crystal substrate 2 is from the maximum value to the maximum value (or from the minimum value to the minimum value). If the amount of movement is grasped, the glass plate 10,
The liquid crystal pitch can be measured with high accuracy by removing the effects of the warpage of 13 and the initial angle setting error.

When the liquid crystal pitch is to be measured with high precision, for example, with an error of 0.1 μm, the luminance of a minute specific area when the fine movement stage 20 is translated at a coarse pitch of 0.05 μm is evaluated. Need
Therefore, simply moving the fine movement stage 20 in parallel at a pitch of 0.05 μm increases the measurement time.

However, given the thickness of the liquid crystal substrates 2 and 3 and the initial setting gap δ, the approximate value P ₁ of the liquid crystal pitch is used to obtain the maximum value (or minimum value) of the fine movement stage 20 of the fine movement stage 20. The movement coordinate value can be predicted.
Therefore, before and after the predicted movement coordinates, 0.05
By performing the maximum value (or minimum value) search by performing parallel movement at the pitch, the measurement time can be reduced. That is, the luminance is measured in three stages as follows.

In the first stage, the moving speed of the fine movement stage 20 (lower liquid crystal substrate 3) is increased to grasp the approximate position where the luminance level is maximum (or minimum). In the second stage, the moving speed of the fine movement stage 20 (lower liquid crystal substrate 3) is reduced (at a pitch of 0.05 or less), and the position where the luminance level becomes maximum (or minimum) is accurately grasped. In the third stage, based on the data of the approximate value P ₁ of the liquid crystal pitch, after moving only P ₁ and the fine movement stage 20 (lower side liquid crystal substrate 3) to increase the moving speed, the moving speed before and after this position Move it to a smaller size to maximize (or minimize) the brightness level
Know exactly where it will be. The moving distance of the fine movement stage 20 (lower liquid crystal substrate 3) from the position where the luminance level is the maximum (or minimum) to the position where the luminance level is the maximum (or the minimum) again, that is, the change amount of the minute gap δ is an accurate liquid crystal pitch. Value.

(4) Measurement of Transmittance / Voltage Characteristics Conventionally, the measurement of the transmittance / voltage characteristics is shown in FIG. 2 after measuring the liquid crystal pitch using a wedge type cell 1 as shown in FIG. A flat cell having the same configuration as that described above is created and performed. That is, as described above, the minute gap δ shown in FIG.
After a plastic ball having a diameter equal to the diameter is mixed into the liquid crystal material to make the minute gap δ uniform, the transmittance / voltage characteristics are measured. In this case, the setting of the minute gap δ is not appropriate due to a measurement error of the liquid crystal pitch, and the reliability of the measurement of the transmittance / voltage characteristic itself is reduced. Further, the liquid crystal pitch measurement and the transmittance / voltage characteristic measurement are separate processes.

On the other hand, in the present liquid crystal evaluation device, after the liquid crystal pitch is measured, the transmittance / voltage characteristics can be continuously measured by the same liquid crystal evaluation device in the same process.
Hereinafter, the measurement procedure will be described.

Coordinate setting of fine movement stage: The fine movement stage 20 is set at a position where the luminance of the minute specific area S ₁ shown in FIG. 4 is a minimum value, for example, the coordinates of C in FIG. Voltage application: The switch 58 shown in FIG. 1 is turned on, and the DC voltage (variable) of the power supply 57 is gradually increased. Measurement of Brightness: by measuring the luminance of a small specific area S ₁ when increasing the applied voltage, graphed corresponding applied voltage (V) and the luminance of the small specific area S _1, as shown in FIG. 6 Obtain transmittance / voltage characteristics. The transmittance on the vertical axis in FIG. 6 corresponds to the luminance. Evaluation of transmittance / voltage characteristics: From the obtained transmittance / voltage characteristics, a contrast ratio and the like are evaluated as follows. T _ON / T _OFF : Contrast ratio Gradient α: Sharpness

[0048]

As described above in detail with the embodiments of the present invention, according to the liquid crystal evaluation apparatus of the present invention, the first and second liquid crystal substrates, the parallel moving means, the moving amount measuring means, By providing the light source and the luminance measuring means, it is not necessary to prepare a wedge-type cell or the like, so that the work becomes easy, and the influence of the warp of the glass plate or the angle setting error is excluded. The liquid crystal pitch can be measured with high accuracy.

Further, by providing the tilting means, the tilt angle measuring means, and the interval measuring means, it is possible to efficiently measure the liquid crystal pitch with high accuracy.

By providing a pair of transparent electrodes and a voltage applying means, the transmittance / voltage characteristics can be measured by the same liquid crystal evaluation device after the liquid crystal pitch measurement. Therefore, the transmittance / voltage characteristics can be measured efficiently.

With the above-described effects, the reliability of the evaluation of the characteristics of the liquid crystal material and the liquid crystal display performance can be improved, and the development man-hour of the liquid crystal material and the liquid crystal display device can be reduced to shorten the development period. Can be planned.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a liquid crystal evaluation device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a liquid crystal substrate provided in the liquid crystal evaluation device shown in FIG.

FIG. 3 is an explanatory diagram of measuring an approximate value of a liquid crystal pitch.

FIG. 4 is an explanatory diagram of high-precision measurement of a liquid crystal pitch.

FIG. 5 is an explanatory diagram of high-precision measurement of a liquid crystal pitch.

FIG. 6 is an explanatory diagram of transmittance / voltage characteristic measurement.

FIG. 7 is a diagram illustrating a configuration of a wedge-type cell used for a conventional liquid crystal pitch measurement and a conventional liquid crystal pitch measurement method.

[Explanation of symbols]

2 upper liquid crystal substrate 3 lower liquid crystal substrate 9,14 polarizing plate 10,13 glass plate 11,12 alignment film 16,17,18 discrimination line 20 fine movement stage 23,24,27,28 concave portion 25,26 exhaust hole 29 Upper holding member 30 Liquid crystal material 31 Test cell 32, 33, 34, 35 Spring portion flexible in y-axis direction 36, 37, 39, 40 Spring portion flexible in x-axis direction 38, 41 Piezoelectric actuator 42, 43 Displacement gauge 44 Base member 45, 46, 47, 48 Stopper plate 49, 50 Ball bush 51, 52 Guide shaft 53, 54 Glass flange 55, 56 Transparent electrode film 57 DC power supply 58 Switch 59, 61 Lens 60 Aperture plate 62 light source 63 light 64 hole 65 CCD camera 66 image processing device 67 personal computer δ upper liquid crystal substrate Clearance with lower liquid crystal substrate S ₁ , S ₂ Micro specific area

Claims (3)

[Claims] 1. A first and a second liquid crystal substrate facing each other with a minute gap for receiving a liquid crystal material to be evaluated, and the first or second liquid crystal substrate is minutely moved substantially in parallel to form the minute gap. A parallel moving means for changing the distance;
Or a movement amount measuring means for measuring a movement amount of the second liquid crystal substrate; a light source for irradiating light from the first or second liquid crystal substrate side; Second
Alternatively, a liquid crystal evaluation device comprising: a luminance measuring means for measuring luminance of a minute specific area of the first liquid crystal substrate. 2. The liquid crystal evaluation device according to claim 1, wherein the tilting means tilts the first or second liquid crystal substrate, and the tilting means tilts the first or second liquid crystal substrate. Tilt angle measuring means for measuring a tilt angle between the first liquid crystal substrate and the second liquid crystal substrate that occurs; and the second or first liquid crystal light source being opposite to the light irradiation side of the light source.
And an interval measuring means for measuring an interval between the discrimination lines generated on the liquid crystal substrate. 3. The liquid crystal evaluation device according to claim 1, further comprising: voltage applying means for applying a variable DC voltage to the transparent electrodes of the first liquid crystal substrate and the second liquid crystal substrate. Liquid crystal evaluation device.