JP3397559B2 - Optical anisotropy measuring device and optical anisotropy measuring method - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical anisotropy measuring apparatus and an optical anisotropy measuring method for measuring the optical anisotropy of a substance.

[0002]

2. Description of the Related Art In manufacturing a liquid crystal device, a treatment such as a rubbing treatment for aligning liquid crystal molecules is generally performed. By this alignment treatment, the liquid crystal molecules are aligned at an angle with respect to the substrate surface of the liquid crystal device during the initial alignment. This angle is called a pretilt angle.

The magnitude of the pretilt angle and the variation of the pretilt angle within the liquid crystal device are one of the major factors that determine the optical performance of the liquid crystal device. In the case of a liquid crystal, unlike the crystal, the size of the pretilt angle often varies more or less depending on the location.

However, it is often preferable that the magnitude of the pretilt angle is uniform in the liquid crystal device.
Therefore, it is important to know the size of the pretilt angle of the liquid crystal and its variation in developing and manufacturing the liquid crystal device. Therefore, the crystal rotation method (Jp
n. J. Appl. Phys. , Vo. 119 (198
0) No. 10. Short Notes 2013)
It is known that the pretilt angle is obtained by measuring the optical anisotropy of liquid crystal using.

Conventionally, for measuring the pretilt angle of the liquid crystal described above, an optical anisotropy measuring apparatus using a crystal rotation method as shown in FIG. 11 is used.

This optical anisotropy measuring apparatus 200 is a He
-Ne laser device 201, polarizer 202, analyzer 20
3, a photodetector 204, a polarizer 202 and an analyzer 2
A liquid crystal cell 205, which is a subject, is placed between the liquid crystal display device 03 and the liquid crystal display device 03.

The liquid crystal cell 205 is provided with an alignment film (for example, a polyimide having a thickness of 0.02 μm and a refractive index of about 1.6: not shown) inside a pair of glass substrates 206a and 206b arranged opposite to each other. , And a liquid crystal layer (about 20 μm thick) 207 is enclosed between the alignment films.

The liquid crystal cell 205 is arranged in a direction orthogonal to the central axis of the incident light flux A (parallel light flux laser light) emitted from the He-Ne laser device 201 (direction perpendicular to the paper surface). It is rotatably supported by a rotating shaft 208. Hereinafter, the central axis of the incident light flux A is the central axis of the light flux immediately after being emitted from the light source (laser device or the like). Here, when the alignment film is subjected to uniaxial alignment treatment for uniaxially aligning the liquid crystal, the uniaxial alignment treatment axis and the rotation axis 2
08 is set to be orthogonal to each other.

Next, with the conventional optical anisotropy measuring apparatus 200 using the above-mentioned crystal rotation method,
The principle of measuring the optical anisotropy of the liquid crystal layer 207 (the principle of calculating the pretilt angle) will be described.

The incident light flux A emitted from the He-Ne laser device 201 passes through the polarizer 202 and then becomes linearly polarized light and enters the liquid crystal cell 205. The incident light flux A that has entered the liquid crystal cell 205 interacts with the liquid crystal molecules to change the polarization state, and normally exits the liquid crystal cell 205 as elliptically polarized light. The outgoing light flux B emitted from the liquid crystal cell 205 passes through an analyzer 203 having a polarization direction parallel or perpendicular to the polarizer 202 and reaches a photodetector 204.

When the liquid crystal cell 205, which is rotatably supported by the rotation axis 208 which is orthogonal to the central axis of the incident light beam A and is perpendicular to the paper surface, is rotated rightward (in the direction of the arrow), for example.
The direction of the director, which is a unit vector representing the direction of the liquid crystal molecules of the liquid crystal layer 207, changes relative to the direction of the electric field vector of the incident light flux A entering the liquid crystal layer 207. Therefore, depending on the rotation angle of the liquid crystal cell 205, the liquid crystal cell 20
The polarization state of the outgoing light flux B exiting from 5 changes.

When the output of the photodetector 204 is plotted against the rotation angle of the liquid crystal cell 205, a characteristic curve as shown in FIG. 12, for example, is obtained. At this time, the method of changing the polarization state according to the rotation angle of the liquid crystal cell 205 differs depending on the size of the pretilt angle of the liquid crystal molecules of the liquid crystal layer 207.
The pretilt angle can be read from this characteristic curve.

Specifically, the pretilt angle is obtained by the following equations (1) and (2). However, the alignment films provided on the glass substrates 206a and 206b of the liquid crystal cell 205 are subjected to rubbing treatments antiparallel to each other, and the polarization direction of the polarizer 202 and the polarization direction of the analyzer 203 are
In both cases, the direction is set at 45 degrees with respect to the direction of the rotary shaft 208.

[0014]

[Formula 1]

[0015]

[Formula 2] However, n ₀ : ordinary ray refractive index of liquid crystal, n _e : extraordinary ray refractive index of liquid crystal, θ: rotation angle of liquid crystal cell 205, α: pretilt angle, T (θ): transmitted light intensity, d: liquid crystal layer 207 , Λ: wavelength of incident light flux A In the above formulas (1) and (2), n ₀ , n _e and λ are known quantities. The shape of the curve (showing the relationship between T (θ) and θ) shown in FIG. 12 depends on the pretilt angle (α) and the thickness (d) of the liquid crystal layer 207.

Therefore, fitting is performed by using, for example, the least square method so that the positions of the peaks and valleys of the curve based on the actual measurement data come close to the theoretical curve drawn by the calculation, and the pretilt angle (α) and the liquid crystal layer. Determine the thickness (d) of 207. In other words, the theoretical curve closest to the curve based on the actual measurement data is drawn to determine the pretilt angle (α) and the thickness (d) of the liquid crystal layer 207.

At this time, the rotation angle of the liquid crystal cell 205 is, for example, when the incident light beam A is vertically incident (state shown in FIG. 11).
Is 0 degrees, it is ± 60 to 70 degrees, and the width is 120 to 1
It covers a range of 40 degrees.

Thus, the optical anisotropy measuring device 2
00 interacts the linearly polarized incident light flux A with the liquid crystal molecules of the liquid crystal layer 207 and measures the change in the polarization state of the light flux B emitted from the liquid crystal cell 205 to determine the optical anisotropy of the liquid crystal layer 207. The measurement is performed and the pretilt angle is calculated.

The optical anisotropy measuring apparatus 200 is
It can be used not only for measuring the pretilt angle but also for measuring the optical anisotropy of other substances.

By the way, in the measurement of the optical anisotropy by the optical anisotropy measuring apparatus 200 described above, when the liquid crystal cell 205 is rotated, the region where the optical anisotropy is measured is also displaced. That is, as shown in FIG. 11, when the incident light flux A emitted from the He-Ne laser device 201 is perpendicularly incident on the substrate surface of the liquid crystal cell 205, the incident light flux A is not refracted and the liquid crystal is refracted. Layer 20
7, the liquid crystal cell 205 is rotated to measure the optical anisotropy of the liquid crystal layer 207, as shown in FIG. 13, and the incident angle of the incident light flux A that is incident on the glass substrate 206a on the incident side. Changes and refracts on the surface of the glass substrate 206a. Since the degree of the refraction changes depending on the rotation angle of the liquid crystal cell 205, the pretilt angle measurement region also changes according to this rotation angle. Therefore, the measurement position shift e occurs.

Specifically, the incident side glass substrate 206a
If the thickness is 1 mm and the refractive index is 1.5, the liquid crystal cell 2
Since 05 is rotated by 70 degrees to one side, the deviation of the measurement position is 4 mm in total. Here, the beam diameter of the incident light flux A emitted from the He-Ne laser device 201 is about 1 mm.
Since it is about φ, it can be understood that the shift of 4 mm is a considerably large shift amount, and the optical anisotropy measurement region is completely changed with the rotation of the liquid crystal cell 205.

On the other hand, a general liquid crystal device used for a display or the like is composed of several hundred thousand to one million minute pixels, though one pixel is several, though it varies depending on its driving method and liquid crystal type. The size is about 10 to several 100 μm square. For example, in an active matrix type liquid crystal device, a partition is formed between pixels in the manufacturing process, and a rubbing process is performed with a cloth made of fibers having a diameter of about 20 μm, so that the pixels are arranged in one pixel or adjacent to each other. Alignment unevenness easily occurs between different pixels. Therefore,
In evaluating and developing such a liquid crystal device, it is very important to measure the pretilt angle in a minute region of at least several μmφ to several tens μmφ. Also, not only the active matrix type liquid crystal device but also the simple matrix type liquid crystal device, it is possible to know the degree of the alignment unevenness by improving the alignment process, the liquid crystal device manufacturing process, and the defective product on the manufacturing line. It is useful for discovering.

However, in the above-described conventional optical anisotropy measuring apparatus 200, since the parallel light flux (incident light flux A) is directly incident on the liquid crystal cell 205, the irradiation area is large (as described above, the incident light flux A Beam diameter is about 1 mmφ
Is about). In addition, as described above, the liquid crystal cell 205
The measurement area shifts with the rotation of. Therefore, there is a problem that it is not possible to measure the pretilt angle in a minute area, and it is impossible to detect unevenness (unevenness of alignment) due to the position of the pretilt angle.

Not only in the liquid crystal cell, but also in the case of examining the optical anisotropy of a substance whose optical anisotropy changes in a specific direction, the measurement area is displaced. , I couldn't find out accurately.

On the other hand, as a method of measuring the pretilt angle of the liquid crystal different from the above-mentioned crystal rotation method, there is known a method of determining the pretilt angle by measuring the optical anisotropy of the liquid crystal using the Senarmont method.

Conventionally, as an optical anisotropy measuring apparatus for measuring the pretilt angle of a liquid crystal by using the Senarmont method, an optical anisotropy measuring apparatus as shown in FIG. 14 has been used.

This optical anisotropy measuring device 210 is equipped with He
-Ne laser device 201, polarizer 202, incident optical system 2
11, an exit optical system 212, a quarter-wave plate 209, an analyzer 203, and a photodetector 204, and is a liquid crystal cell 205 which is a subject between the entrance optical system 211 and the exit optical system 212.
Are arranged.

The liquid crystal cell 205 has an alignment film (for example, a polyimide having a thickness of 0.02 μm and a refractive index of about 1.6: not shown) inside each of a pair of glass substrates 206a and 206b arranged to face each other. , And a liquid crystal layer (about 20 μm thick) 207 is enclosed between the alignment films.

The liquid crystal cell 205 is arranged in a direction orthogonal to the central axis of the incident light flux A (parallel light flux) emitted from the He-Ne laser device 201 (direction perpendicular to the plane of the drawing). It is rotatably supported by a rotating shaft 208. The analyzer 203 is rotatably supported by a rotating shaft (not shown) arranged in a direction parallel to the central axis of the incident light flux A emitted from the He-Ne laser device 201. Next, the principle of measuring the optical anisotropy of the liquid crystal layer 207 (principle of calculating the pretilt angle) by the conventional optical anisotropy measuring apparatus 210 using the Senarmont method described above will be described.

The incident light beam A emitted from the He-Ne laser device 201 passes through the polarizer 202, becomes linearly polarized light, is converged by the incident optical system 211, and enters the liquid crystal cell 205. The incident light flux A that has entered the liquid crystal cell 205 is
The polarization state is changed by interacting with the liquid crystal molecules, and the light normally exits the liquid crystal cell 205 as elliptically polarized light. Liquid crystal cell 205
The outgoing light beam B emitted from the light beam is converted into a parallel light beam by the outgoing optical system 212, passes through the quarter wavelength plate 209 and the analyzer 203, and reaches the photodetector 204.

When the liquid crystal cell 205, which is rotatably supported by a rotary shaft 208 which is orthogonal to the central axis of the incident light beam A and is perpendicular to the paper surface, is rotated rightward (in the direction of the arrow), for example.
The direction of the director, which is a unit vector indicating the direction of the liquid crystal molecules of the liquid crystal 207, changes relative to the direction of the electric field vector of the incident light flux A that enters the liquid crystal layer 207. Therefore, according to the rotation angle of the liquid crystal cell 205, the liquid crystal cell 205
The polarization state of the outgoing light flux B exiting from changes.

At this time, the analyzer 203 is rotated according to the rotation angle of the liquid crystal cell 205. Then, using the photodetector 204, the azimuth of extinction of the outgoing light flux B is obtained. Specifically, for example, the liquid crystal cell 205 is rotated by 0.5 degrees,
The liquid crystal cell 205 is once fixed at each rotation angle, and the analyzer 203 is rotated to obtain the extinction direction of the outgoing light flux B. Thereby, the phase difference between the ordinary ray and the extraordinary ray passing through the liquid crystal layer 207 can be measured.

Then, with respect to the rotation of the liquid crystal cell 205,
The phase difference between the ordinary ray and the extraordinary ray passing through the liquid crystal layer 207 is plotted. Depending on the size of the pretilt angle, the liquid crystal cell 2
The magnitude of the pretilt angle of the liquid crystal molecules of the liquid crystal layer 207 can be calculated from this curve based on the fact that the change in the phase difference between the ordinary ray and the extraordinary ray due to the rotation of 05 differs.

Specifically, the pretilt angle is obtained by the following equation (3). However, the liquid crystal cell 205
The alignment films provided on the glass substrates 206a and 206b of are subjected to rubbing treatments antiparallel to each other, and
The polarization direction of is set at 45 degrees with respect to the rotation axis 208 direction.

[0035]

[Formula 3] Where δ (θ): phase difference between ordinary ray and extraordinary ray, n ₀ :
Ordinary refractive index of the liquid crystal, n _e: LCD extraordinary refractive index,
θ: rotation angle of the liquid crystal cell 205, α: pretilt angle, d:
Thickness of liquid crystal layer 207, λ: wavelength of incident light flux A In the above formula (3), n ₀ , n _e and λ are known quantities.
The curve (horizontal axis: θ and vertical axis: δ (θ)) representing the relationship between the rotation angle (θ) of the liquid crystal cell 205 by the Senarmont method and the phase difference δ (θ) between the ordinary ray and the extraordinary ray is δ (θ) The curve has one maximum value of.

Here, the value of θ at which δ (θ) becomes maximum (hereinafter referred to as θ _x ) depends only on the value of α (the magnitude of δ (θ) depends on α and d). . give theta _x which matches with the measured value of theta _x, to determine α by obtaining a theoretical curve drawn by calculation.

Although the optical anisotropy can be measured by the same method without using the quarter-wave plate 209, the measurement accuracy is improved by using the quarter-wave plate 209.

Thus, this optical anisotropy measuring device 2
Numeral 10 causes the linearly polarized incident light flux A to interact with the liquid crystal molecules of the liquid crystal layer 207, and changes the phase difference between the ordinary ray and the extraordinary ray of the light flux B emitted from the liquid crystal cell 205. The optical anisotropy is measured and the pretilt angle is calculated.

The optical anisotropy measuring device 20 mentioned above is used.
0 and the optical anisotropy measuring apparatus 210 are both modified as described below to obtain an optical anisotropy measuring apparatus by the crystal rotation method or an optical anisotropy measuring apparatus by the Senarmont method. Can be any of the above devices.

That is, by fixing the analyzer 203 and not providing the quarter-wave plate 209, an optical anisotropy measuring apparatus by the Krustal rotation method is obtained, and the analyzer 20 is provided.
By making 3 rotatable, and providing the quarter-wave plate 209 for improving the measurement accuracy, the optical anisotropy measuring device by the Senarmont method is obtained.

Further, the analyzer 203 is rotatably and easily fixable, and the quarter wavelength plate 209 is arranged on the optical path of the outgoing light beam B at a position where it can be moved as needed, whereby the crystal rotation is performed. The optical anisotropy measuring device is capable of measuring the optical anisotropy by either the method or the Senarmont method.

[0042]

By the way, the optical anisotropy measuring apparatus 210 using the above-described conventional Senarmont method is used.
However, there is a problem similar to that of the optical anisotropy measuring apparatus 200 using the crystal rotation method, and the unevenness (change) of the pretilt angle of the liquid crystal 207 cannot be detected with the spatial resolution of about 10 μm or less. .

That is, as the liquid crystal cell 205 rotates, a displacement e of the measurement position occurs, and the liquid crystal 20 in the same area.
The optical anisotropy of 7 cannot be measured (see FIG. 13).

Therefore, the position of the rotation axis is derived such that the displacement e of the measurement position generated according to the rotation angle of the liquid crystal cell 205 is minimized, and the liquid crystal cell 2 is centered on the rotation axis.
05 has been proposed (KY Ha.
net. al. , Jpn. J. Appl. Phys.
Vol. 32 (1993) pp. L277-L27
9). This method can be applied to measurement by either the crystal rotation method or the Senarmont method.

The simple principle of this method will be described with reference to FIG. In this figure, the rotation angle of the liquid crystal cell 205 (that is, the angle with the incident angle of the incident light flux A on the incident side glass substrate 206a) is θ, the normal line of the glass substrate 206a and the incident light flux A in the glass substrate 206a. Is θ ^, and 1/2 of the thickness of the liquid crystal cell 205 is F, and the glass substrate 206a is
Where n is the refractive index of E, the displacement of the measurement position is e, and the distance of the rotation axis 218 from the center position of the liquid crystal 207 is X, the displacement e of the measurement position is expressed by the following equation (4).

[0046] e = (F-X) tanθ -Ftanθ, ...... (4) However, it is sinθ = ^nsinθ,.

The optimum position of the rotation angle 218 corresponding to the rotation angle of the liquid crystal cell 205 can be determined by obtaining the relationship between θ and X where e = 0 from the equation (4).

However, in this method, the liquid crystal cell 2
It is necessary to change the position of the rotary shaft 218 in the order of μm in accordance with the rotation of 05, which requires a highly precise and complicated mechanism.

Therefore, in an actual device, in the Senarmont method, first, an appropriate rotation axis is temporarily set and the liquid crystal cell 20 is tentatively determined.
By rotating 5 the approximate magnitude of the pretilt angle is determined. Next, the range of the rotation angle required for the measurement is obtained according to the magnitude of the pretilt angle, the position of the rotary shaft 218 is obtained so that the deviation of the measurement position is minimized in the range, and the measurement position is determined within the range. The position of the rotary shaft 218 is determined so that the deviation is minimized, and the measurement is performed. Therefore, in actuality, the deviation of the measurement position does not become 0, and the deviation of about 3 to 5 μm occurs, and it takes time for one measurement.

Therefore, this method is inconvenient for detecting the unevenness of the pretilt angle in the minute area of the liquid crystal 207 with the spatial resolution of about several μm. On the other hand, in the crystal rotation method, since a rotation range of ± 60 to 70 degrees is required, the displacement of the measurement position is several tens of μm.

Further, in the optical anisotropy measurement by the Senarmont method, when the rotation angle of the liquid crystal cell 208 is, for example, 0 to 60 degrees, the magnitude of the pretilt angle can be calculated only in the range of about 0 to 13 degrees. There was a problem.

By the way, in the optical anisotropy measuring apparatus 210 shown in FIG. 14, the incident light beam A is converged by using the incident optical system 211 in order to enable measurement in a minute area. In both the crystal rotation method and the Senarmont method, in order to measure the optical anisotropy in the minute area of the liquid crystal 207, it is necessary to use the incident optical system as shown in FIG. is there. However, when the liquid crystal cell 205 is rotated, the incident angle of the incident light flux A with respect to the glass substrate 206a on the incident side changes. Then, as the rotation angle of the liquid crystal cell 205 increases, spherical aberration and astigmatism generated due to the influence of the glass substrate 206a increase. Therefore, the incident light flux A could not be converged on a minute area of about several μmφ.

The spherical aberration and the astigmatism are the F number of the convergent light beam of the incident light system A of the incident light beam A, the residual aberration of the incident optical system 211, the thickness of the glass substrate 206a on the incident side, and the rotation of the liquid crystal cell 205. Depends on corners etc. For example,
The glass substrate 206a has a thickness of 1 mm and a refractive index of 1.51.
5, the incident light flux A is converged in the air by using an optical system capable of converging to a beam diameter of 5 μmφ, and the liquid crystal cell 20
When the rotation angle of No. 5 is 45 degrees, it is possible to converge only about 7 μm in the axial direction of the rotation axis 208 mainly due to the influence of spherical aberration,
Mainly due to the effect of astigmatism, only about 50 μm can be converged in the direction perpendicular to the rotation axis 208. That is, the spatial resolution is about 7 μm in the axial direction of the rotary shaft 208.
The thickness is about 50 μm in the direction perpendicular to.

Under the same conditions, the incident light flux A is set to 1 in the air.
When an optical system that can converge to a beam diameter of μmφ is used for focusing, the effect of astigmatism becomes larger, and the incident light beam A
The convergent diameter of depends largely on how to determine the position of the focal point (because a clear focal point cannot be determined due to the influence of astigmatism). Specifically, when the convergent diameter is the smallest in the direction of the rotation axis 208, the spatial resolution is 60 μm in the direction of the rotation axis 208.
And about 230 μm in the direction perpendicular to the rotation axis 208. On the other hand, when the convergent diameter is the smallest in the direction perpendicular to the rotary shaft 208, the spatial resolution is about 100 μm in the axial direction of the rotary shaft 208 and 10 in the direction perpendicular to the rotary shaft 208.
It becomes about 0 μm.

Further, under the same conditions, the incident light flux A is changed to 2 in the air.
When converging with an optical system capable of converging to a beam diameter of 0 μmφ, the spatial resolution is 20 in the axial direction of the rotation angle 208.
and about 45 μm in the direction perpendicular to the rotation axis 208.

Thus, the F number is small (N.
A. The more the optical system (having a large numerical aperture) is used to converge the incident light flux A with a smaller diameter, the greater the influence of astigmatism due to the rotation of the glass substrate 206a.

Therefore, as in the optical anisotropy apparatus 210 using the conventional Senarmont method shown in FIG. 14, the incident light beam A is converged by using the incident optical system, and the liquid crystal 2
Even if the optical anisotropy in the minute region of 07 is measured (for example, even if the incident light flux A is converged on the liquid crystal 207 by an optical system capable of converging to a beam diameter of several μmφ or less in the air), It was not possible to measure the pretilt angle in a minute region of 10 μmφ or less.

Therefore, according to the present invention, by arranging a predetermined transparent member having a curved surface portion and a flat surface portion in close contact with the subject, the optical anisotropy of the same region can be obtained despite the rotation of the subject. An object of the present invention is to provide an optical anisotropy measuring device for measuring the property and a measuring method thereof.

Further, according to the present invention, by disposing a flat plate-shaped transparent member which rotates in the opposite direction of the rotation of the subject between the light source and the subject, the optical region of the same region can be rotated regardless of the rotation of the subject. An object is to provide an optical anisotropy device for measuring anisotropy and a measuring method thereof.

Further, according to the present invention, in addition to any of the above-mentioned transparent members, a predetermined incident optical system is arranged between the light source and the subject, so that an optical anisotropy can be obtained in a minute area of the subject. An object of the present invention is to provide an optical anisotropy measuring device for measuring the property and a measuring method thereof.

[0061]

[0062]

[0063]

[0064]

[0065]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a light source for emitting a light beam and a photodetector arranged to face the light source, and the center of the light beam is provided. An optical anisotropy measuring device for measuring the optical anisotropy of a subject arranged between the light source and the photodetector so as to intersect the axis, wherein the subject is in a direction orthogonal to the central axis. A support member that rotatably supports about the axis, a polarizer that polarizes the light flux disposed on the central axis between the light source and the subject, and the center between the subject and the photodetector. An analyzer that polarizes the light flux arranged on the axis, and a pair of transparent members that are arranged opposite to each other having a curved surface portion and a flat surface portion, and a pair of transparent members that sandwich the subject between the respective flat surface portions. A member and at least the light flux polarized by the polarizer, The incident light is made incident on the subject through the transparent member, the light flux emitted from the subject is made incident on the photodetector through the analyzer, and the change in the polarization state of the light flux is detected by the photodetector. Is characterized in that the optical anisotropy of the subject is measured.

The present invention also includes a light source for emitting a light beam,
An optical detector that has a photodetector disposed opposite to the light source, and that measures the optical anisotropy of the subject disposed between the light source and the photodetector so as to intersect with the central axis of the light flux. An anisotropy measuring apparatus, comprising: a support member that rotatably supports the subject with a direction orthogonal to the central axis as a first axis, and arranged on the central axis between the light source and the subject. A polarizer, an analyzer arranged on the central axis between the subject and the photodetector, and arranged on the optical axis between the light source and the subject, the first axis; A first parallel transparent member rotatably supported with a parallel direction as a second axis, and the light flux polarized by the polarizer is rotated at an equal angular velocity in a direction opposite to that of the subject. The first rotated
By passing through the parallel transparent member, the light flux emitted from the subject to the photodetector through the analyzer, by detecting a change in the polarization state of the light flux in the photodetector It is characterized in that the optical anisotropy of the subject is measured.

Furthermore, the present invention comprises a light source for emitting a light beam,
An optical detector for measuring the optical anisotropy of an object, which has a light detector facing the light source and is arranged between the light source and the light detector so as to intersect the central axis of the light flux. In the isotropic measuring device, a support member that rotatably supports the subject around an axis orthogonal to the central axis, and the light flux disposed on the central axis between the light source and the subject. A polarizer to be polarized, an incident optical system arranged on the central axis between the light source and the subject, and the light flux arranged on the central axis between the subject and the photodetector are polarized. An analyzer, and a pair of transparent members facing each other each having a curved surface portion and a flat surface portion, the pair of transparent members sandwiching the subject between the respective flat portions, the subject and a photodetector. And an output optical system disposed on the central axis between The light beam polarized by a child is made incident on the subject through the incident optical system and a transparent member, and the light beam emitted from the subject is made incident on the photodetector through the analyzer and the emission optical system. The optical anisotropy of the subject is measured by detecting a change in the polarization state of the light flux with the photodetector.

The present invention also includes a light source for emitting a light beam,
An optical detector for measuring the optical anisotropy of an object, which has a light detector facing the light source and is arranged between the light source and the light detector so as to intersect the central axis of the light flux. An isotropic measurement method, wherein the subject is supported by a support member rotatable about a direction orthogonal to the optical axis, and a polarizer is provided on the central axis between the light source and the subject. While arranging, the analyzer is arranged on the central axis between the subject and the photodetector, and further, the respective flat surface portions of the pair of transparent members which are opposed to each other and have a curved surface portion and a flat surface portion. By sandwiching the subject between, the light flux polarized by the polarizer,
The transparent member is passed through the inside of the subject, the light flux emitted from the subject is incident on the photodetector through the analyzer, and the polarization state of the light flux is changed by the photodetector. Is detected to measure the optical anisotropy of the subject.

Further, according to the present invention, a light source for emitting a light beam,
An optical detector that has a photodetector disposed opposite to the light source, and that measures the optical anisotropy of the subject disposed between the light source and the photodetector so as to intersect with the central axis of the light flux. An anisotropy measuring method, wherein the subject is supported by a support member rotatable about a direction orthogonal to the central axis as a first axis, and
A polarizer is arranged on the central axis between the light source and the object, and an analyzer is arranged on the central axis between the object and the photodetector, and the light source and the object are further arranged. And a first parallel transparent member is rotatably supported with a direction parallel to the first axis as a second axis, and the light beam polarized by the polarizer is directed in a direction opposite to the subject. The light flux that has passed through the first parallel transparent member rotated at an equal angular velocity and is emitted from the subject enters the photodetector through the analyzer, and the photodetector polarizes the light flux. It is characterized in that the optical anisotropy of the subject is measured by detecting a change in state.

The present invention also includes a light source for emitting a light beam,
An optical detector for measuring the optical anisotropy of an object, which has a light detector facing the light source and is arranged between the light source and the light detector so as to intersect the central axis of the light flux. An isotropic measuring method, wherein the subject is supported by a support member rotatable about a direction orthogonal to the center axis, and a polarizer is provided on the center axis between the light source and the subject. While arranging, the analyzer is arranged on the central axis between the subject and the photodetector, and further, the respective flat surface portions of the pair of transparent members which are opposed to each other and have a curved surface portion and a flat surface portion. The subject is sandwiched between them, and the incident optical system is arranged on the central axis between the light source and the subject, and the light is emitted on the central axis between the subject and the photodetector. An optical system is arranged, and the light beam polarized by the polarizer is transmitted through the incident optical system and a transparent member to the target. The light flux that has passed through the body and is emitted from the subject is incident on the photodetector through the emission optical system and the analyzer, and the photodetector detects a change in the polarization state of the light flux. It is characterized in that the optical anisotropy of the subject is measured.

[0071]

[0072]

[0073]

[0074]

[0075]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing the structure of the optical anisotropy measuring apparatus according to the first embodiment. This optical anisotropy measuring device 10 is a He-Ne laser device (light source).
1, a polarizer 3, an analyzer 3, and a photodetector 4, and a liquid crystal cell 5 as an object is disposed between the polarizer 2 and the analyzer 3.

The liquid crystal cell 5 comprises a pair of glass substrates 6a and 6b arranged to face each other, an alignment film (not shown) formed inside each of them, and a liquid crystal layer 7 injected between the alignment films. The cell 5 is provided with a supporting member (not shown), and the rotary shaft 8 is attached so as to be orthogonal to the optical axis (center axis) of the incident light flux A (laser light flux) emitted from the light source 1.
It is rotatably supported by and is rotated in the arrow direction or the opposite direction by a rotary drive device (not shown) connected to the rotary shaft 8. Here, when the alignment film is subjected to uniaxial alignment treatment for aligning the liquid crystal layer 7, the uniaxial alignment treatment axis and the rotation axis 8 are set to be orthogonal to each other.

The polarizer 3, the analyzer 3, and the photodetector 4 are located on the central axis of the incident light beam A emitted from the light source 1.

On the polarizer 3 side of the glass substrate 6a on the incident side and on the analyzer 3 side of the glass substrate 6b on the emitting side, spherical glass 11a and 11b are provided as refractive index matching liquids (not shown).
Is attached through each of the ball-less glass 11a, 1
1b is formed so that its center of curvature coincides with the intersection of the center of rotation of the liquid crystal cell 5 (axial direction of the rotation axis 8) and the center axis of the incident light beam A. The rotation axis 8 indicates the center of rotation of the liquid crystal cell 5 and is not an axis that actually penetrates the liquid crystal cell 5.

The aforesaid deflated glass 11a, 11b.
Cannot be said to be a strict hemisphere because its center of curvature is in the liquid crystal layer 7, but can be regarded as a substantially hemisphere because the liquid crystal cell 5 is thin.

Further, the spherical glass 11a, 11b is made of a glass material having a refractive index substantially equal to that of the glass substrate 6a, 6b of the liquid crystal cell 5, and the refractive index matching liquid is also substantially equal to that of the glass substrate 6a, 6b. A liquid having a refractive index is used. As the refractive index matching liquid, specifically, index matching oil or the like used in a wet microscope can be used.

Incidentally, the aforesaid spherical glass 11a, 11b,
The glass substrates 6a, 6b and the refractive index matching refractive index are substantially equal to each other means that even if the liquid crystal cell 5 is rotated at the time of measurement, the interfaces between the spherical glass 11a, 11b and the refractive index matching liquid,
And is equal to the degree that total reflection of the incident light flux A does not occur at the interface between the refractive index matching liquid and the glass substrates 6a and 6b, and the incident angle of the incident light flux A to the interface (rotation range of the liquid crystal cell) is It can be set accordingly. Then, the refractive index of the refractive index matching liquid is 11
It is preferable that the refractive index of each of a, 11b and the glass substrates 6a, 6b is within ± 0.05.

The glass substrates 6a and 6b are formed of a glass material which is transparent or almost transparent (more preferably transparent) and has no optical anisotropy. The sphere-free glasses 11a and 11b and the glass substrates 6a and 6b do not necessarily have to be made of glass, and preferably transparent or almost transparent members having no optical anisotropy can be used instead.

As the light source, in addition to the He-Ne laser device 1, a laser device such as an Ar laser device or a semiconductor laser device, or a light beam emitting device such as a heat light source other than the laser device can be used. It must be a device that produces a luminous flux that can be illuminated. Further, the light source is preferably a device having no aberration such as astigmatism, and the light beam is preferably monochromatic light having no chromatic aberration.

As the photodetector 4, an optical power meter, photomultiplier, etc. are used.
High sensitivity is preferable.

When the optical anisotropy is measured by the crystal rotation method, the analyzer 3 is arranged so as to have a polarization direction parallel to or perpendicular to the analyzer 3 (parallel Nicols or crossed Nicols). On the other hand, when the optical anisotropy is measured by the Senarmont method, the analyzer 3 is rotatably arranged by a rotation axis (not shown) arranged in the direction parallel to the central axis of the incident light beam A. . Further, when measuring the optical anisotropy by the Senarmont method, it is preferable that a quarter wavelength plate (not shown) is arranged between the spherical glass 11b and the analyzer 3.

The optical anisotropy measuring apparatus in each of the following embodiments can also be measured by the crystal rotation method or the Senarmont method by making the above-described changes. Further, the analyzer 3 is rotatably arranged so as to be easily fixed so as to have a polarization direction parallel or perpendicular to the polarizer 2, and a quarter wavelength plate is provided on the optical path of the outgoing light flux B only when necessary. An optical anisotropy measuring device which can perform measurement by either the crystal rotation method or the Senarmont method can be provided by disposing the optical anisotropy measuring apparatus at a movable position.

Next, the optical anisotropy measuring device 10 described above is used.
Liquid crystal layer 7 using the crystal rotation method according to
Optical anisotropy measurement method (pretilt angle calculation method)
Will be described.

The incident light flux (laser light flux) A emitted from the He-Ne laser device 1 passes through the polarizer 2 and then becomes linearly polarized light and enters the spherical glass 11a. Then, the incident light flux A converges to some extent and enters the liquid crystal cell 5 by entering the spherical glass 11a. Then, it interacts with the liquid crystal molecules of the liquid crystal 7 and emits the liquid crystal cell 5.

As mentioned above, the deflated glass 11a,
Since 11b and the liquid crystal cell 5 are in close contact with each other via a refractive index matching liquid, and the refractive indexes of the spherical glasses 11a and 11b, the glass substrates 6a and 6b, and the refractive index matching liquid are substantially the same, the incident light flux A enters the liquid crystal cell 5 without being refracted on the surface of the glass substrate 6a. Also,
Since the centers of curvature of the spherical glasses 11a and 11b are on the axis of the rotation axis 8, the measurement area does not change even when the liquid crystal cell 5 is rotated (however, the measurement area slightly increases as the liquid crystal cell 5 rotates). ).

The emitted light beam B emitted from the spherical glass 11b passes through the analyzer 3 arranged so as to have a polarization direction parallel or perpendicular to the polarizer 2 and reaches the photodetector. At this time, the liquid crystal cell 5 supported by the rotary shaft 8 is rotated by a rotation driving device (not shown) in the arrow method or in the direction opposite to the arrow, and the liquid crystal cell 5 is rotated.
The polarization state of the emitted light beam B emitted from the liquid crystal cell 5 changes in accordance with the rotation angle of. The amount of light passing through the analyzer 3 changes depending on the polarization state of the emitted light beam B. Therefore, by plotting the output of the photodetector 4 against the rotation angle of the liquid crystal cell 5, for example, the characteristic curve as shown in FIG. Then, the pretilt angle of the liquid crystal 7 can be obtained from this characteristic curve.

As described above, according to the present embodiment, even if the liquid crystal cell 5 is rotated, the measurement is performed in the same region,
Since the measurement area does not shift, the pretilt angle of this measurement area can be accurately calculated.

Next, a second embodiment according to the present invention will be described with reference to FIG. The same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the optical anisotropy measuring apparatus 20 according to this embodiment, a convex lens (incident optical system having positive power) 21 is arranged between the polarizer 2 and the spherical glass 11a. , He-Ne laser device 1 is configured to convert an incident light flux A into a convergent light flux (convergent spherical wave). In the present embodiment, the focal position of this convergent light beam and the center of curvature of the spherical glass 11a are configured to coincide with each other. Therefore, the incident light flux A converged by the convex lens 21 is the spherical glass 1
The measurement area is focused without refracting at the spherical surface of 1a.

As described above, according to the present embodiment, even if the liquid crystal cell 5 is rotated, the measurement is performed in the same region (however, the size slightly changes), and the measurement region does not shift. The pretilt angle of this measurement area can be calculated accurately. Further, according to the present embodiment, the incident light flux A is converged by the convex lens 21 and focused on the center of rotation of the liquid crystal cell 5, so that measurement in a minute area becomes possible. Further, the presence of the spherical glass 11a solves the conventional problems of spherical aberration and astigmatism when measuring a minute area.

Therefore, with a remarkably excellent resolution, for example, 1
The unevenness of the pretilt angle in one pixel can also be detected, and information effective for improving the manufacturing process of the liquid crystal device and the characteristics of the liquid crystal device itself can be obtained.

By the way, the beam diameter at the converging point, that is, the beam diameter on the measurement surface is mainly N.V. of the convex lens 21. A.
(Numerical Aperture: Numerical Aperture) of the convex lens 21. A. The measurement area can be miniaturized by increasing.
In the present embodiment, the beam diameter of the incident light flux (parallel light flux) A emitted from the He-Ne laser device 1 is about 1 m.
In contrast to mφ, the convergent beam diameter is about 30 μmφ.

Here, if there is no aberration in the convex lens 21, the beam can be converged to the diffraction limit. On the other hand, when such a convex lens 21 is used, the incident light flux becomes convergent light and irradiates the liquid crystal interface, so that the incident angle to the liquid crystal interface becomes wide and the measurement accuracy may be slightly deteriorated. This deterioration of measurement accuracy is caused by N.M. A. The larger is the more remarkable.

However, in the vicinity of the convergence point of the convergent light flux, the convergent light flux is close to a parallel light flux, so that the spread of the incident angle on the measurement area does not become so large as to deteriorate the measurement accuracy.

Next, a third embodiment according to the present invention will be described with reference to FIG. The same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the optical anisotropy measuring apparatus 30 according to this embodiment, two convex lenses 31 and 32 are arranged between the polarizer 2 and the spherical glass 11a to make the incident light having a positive power. It forms an optical system. Among these, the convex lens 31 arranged in the vicinity of the polarizer 2 receives the incident light flux A
It is configured to convert the (parallel light flux) into a convergent light flux (convergent spherical wave). The incident light flux A once converged by the convex lens 31 has an expanded beam diameter (becomes a divergent light flux),
It is incident on the other convex lens 32. This convex lens 32
Is the convergent beam (convergent spherical wave) of the incident divergent beam.
Is configured to convert to.

In other words, in the present embodiment, the large N.V. A. To obtain the focal position of the convergent light beam entering the liquid crystal interface and the aspherical glass 11a.
It is configured so that the center of curvature of is coincident with.

As described above, according to the present embodiment, a larger N. A. Can be obtained, and the beam diameter of the convergent light beam incident on the liquid crystal interface can be reduced to several μmφ. Therefore, the optical anisotropy of the liquid crystal in a region smaller than that in the second embodiment described above can be obtained. Sex can be measured. Further, as in each of the above-described embodiments, even if the liquid crystal cell 5 is rotated, the measurement can be performed in the same measurement region, so that the pretilt angle in this measurement region can be accurately measured.

By the way, in each of the above-mentioned second and third embodiments, the convex lenses 21, 31, 32 (incident optical system having positive power are arranged so that the incident light flux A converges on the rotation center of the liquid crystal cell 5. ) Has been placed, but it need not be limited to this.

That is, the converging position may be moved by moving the incident optical system in the optical axis direction. In addition, one or a plurality of circular apertures (diaphragm means) are installed on the central axis of the incident light flux A between the incident optical system and the spheroidal glass 11a, and an effective N is obtained by using these circular apertures. , A. May be changed. This allows
The area of the measurement region at the liquid crystal interface can be changed, and it is possible to investigate from which size region the unevenness of the pretilt angle becomes remarkable. At this time, the size of the circular opening may be variable.

Next, a fourth embodiment according to the present invention will be described with reference to FIG. The same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

The optical anisotropy measuring apparatus 40 according to the present embodiment has the same incident optical system (convex lenses 31, 3) as the optical anisotropy measuring apparatus 30 according to the above-mentioned third embodiment.
2), and in addition, a convex lens (first emission optical system) 41 is arranged between the spherical glass 11b and the analyzer 3, and between the analyzer 3 and the photodetector 4. A convex lens (second emission optical system) 42 is arranged.

Then, these convex lenses (second emission optical systems) 41 and 42 convert the emitted light beam B, which becomes a divergent light beam and is emitted from the spherical glass 11b, into a parallel light beam,
It is incident on the photodetector 4. In the present embodiment, each of the first and second exit optical systems has a single convex lens 4
1, 42 are used, the first and second emission optical systems may be composed of a plurality of lenses.

In general, when a polarizing element such as a Glan-Thompson prism is used as the analyzer 3, the analyzer 3
Has an incident angle dependency. That is, when the light fluxes incident on the analyzer 3 have respective angle components, the incident angle on the analyzer 3 is within an allowable range (± 7 for the Glan-Thompson prism).
If there is a component exceeding the degree (about a degree), the performance of the analyzer 3 deteriorates (for example, the polarization component in the direction perpendicular to the polarization direction of the analyzer 3 is transmitted), and the measurement accuracy deteriorates.

However, according to the present embodiment, the light flux incident on the analyzer 3 is a convex lens (second emission optical system).
Since the parallel light flux is formed by 41, deterioration of measurement accuracy can be prevented. Further, since the parallel light flux that has passed through the analyzer 3 is converged by the convex lens (second emission optical system) 42, the amount of light incident on the photodetector 4 increases and the detection efficiency improves.

Further, also in this embodiment, the same effect as that of each of the above-described embodiments can be obtained. That is,
Regardless of the rotation of the liquid crystal cell 5, the pretilt angle in the same region can be accurately calculated, and the measurement accuracy is improved.
Also, it becomes possible to calculate the pretilt angle in a minute area,
It is possible to obtain information effective for improving the manufacturing process of liquid crystal devices.

Next, a fifth embodiment according to the present invention will be described with reference to FIG. FIG. 5 is an enlarged schematic view of the vicinity of the liquid crystal cell 5 in the optical anisotropy measuring device 50 according to the present embodiment.

In the optical anisotropy measuring apparatus 50 according to the present embodiment, the spherical glass 11a, 11b is formed continuously with the spherical cutout 51a, 51b and the spherical cutout 51a, 51b, respectively. Flat plate portions 52a and 52b, and the refractive index matching liquid 54 is applied to the flat plate portions 52a and 52b.

The upper and lower ends of the liquid crystal cell 5 with respect to the plane of the drawing are grasped and positioned by liquid crystal cell holders 53 and 55 having a substantially U-shaped cross section. In addition, around the liquid crystal cell holders 53 and 55, the cross section is almost "U".
The letter-shaped bulbous glass holders 56 and 57 are arranged, and are configured to hold the bulbous glasses 11a and 11b. The liquid crystal cell 5 is held between the two spherical glass pieces 11a and 11b by the liquid crystal cell holders 53 and 55 and the spherical glass holders 56 and 57.

The liquid crystal cell holders 53 and 55 and the deflated glass holders 56 and 57 are moved by a feeding mechanism (not shown) to
The liquid crystal cell 5 is supported so as to be movable in a dimension (vertical direction of the paper surface and a direction perpendicular to the paper surface), and is configured to be able to move the position of the liquid crystal cell 5 with respect to the spherical glass 11a, 11b at a pitch of several μm. There is.

In the present embodiment, explanations other than those shown in FIG. 5 are omitted, but the respective optical systems in the optical anisotropy measuring apparatus according to each of the above-mentioned embodiments are implemented in the present embodiment. It can also be used in the optical anisotropy measuring apparatus 50 according to the above embodiment.

As described above, according to the present embodiment, the pretilt angle in the desired region of the liquid crystal cell 5 can be calculated, and the information effective for improving the manufacturing process can be obtained.

Next, a sixth embodiment according to the present invention will be described with reference to FIG. The same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

The optical anisotropy measuring apparatus 60 according to the present embodiment is an apparatus for measuring the optical anisotropy by the Senarmont method, and is provided on the side of the liquid crystal cell 5 which is the subject of the analyzer 3. The / 4 wavelength plate 9 is provided, and the incident optical system 61 for converging the incident light flux A is provided between the polarizer 2 and the incident side spherical glass 11a. In this optical anisotropy measuring device 60, the quarter wave plate 9 can be removed from the optical path of the emitted light beam B and the analyzer 3 can be fixed to apply the optical anisotropy measurement by the crystal rotation method. Needless to say.

The incident optical system 61 preferably converges the incident light flux A emitted from the He-Ne laser device 1 into a beam diameter of 1 to 20 μmφ. In this embodiment,
In the incident optical system 61, if the beam diameter of the incident light beam A that is incident on the lens closest to the spherical glass 11a is d and the focal length of the lens closest to the spherical glass 11a is f, then the convergent light beam by the incident optical system 61 is The F number of is represented by f / d. Further, generally, in a lens or a lens group that plays a role of converging a light flux, when the diameter of the light flux passing through the lens pupil plane is φ and the focal length is f ₀ , the F number is represented by f ₀ / φ. To be done.

Incident optical system 61 used in the present embodiment
The smaller the F number of the convergent light flux of the incident light flux A, the more the incident light flux A can be converged. However, since the range in which the liquid crystal cell 5 is rotated becomes narrower as the convergence angle increases, it is preferable that the convergent light flux A be converged. F number is π /
Incident optical system 61 such that it becomes 5π or more and 3π / 2λ or less
Is preferably used (however, the wavelength (μm) of the incident light flux A)
Is).

In the present embodiment, F of the convergent light flux is
When the number is 7.44, the thickness of the liquid crystal layer 7 is 1 μm, and the wavelength of the incident light flux A is 0.6328 μm, the incident light flux A converges to a beam diameter of about 6 μmφ, and the size of the measurement area is the rotation axis 8 It is about 6.0 μm in the direction parallel to, and about 9.6 μm in the direction perpendicular to the rotation axis 8.

If the F number is set to 1.24 under the same conditions, the incident light beam A converges to a beam diameter of about 1 μmφ, and becomes about 2.7 μm in the direction perpendicular to the rotation axis 8. Also, He
By using an Ar laser device as a light source instead of the —Ne laser device 1, the measurement area can be further reduced.

[0124] Further, the bulging glass 11b on the exit side and 1/4
Between the wave plate 9 and the wave plate 9, an emitting optical system 62 for making the emitted light beam B incident on the analyzer 3 into a parallel light beam is provided. still,
In this embodiment, the incident optical system 61 includes three convex lenses,
Although the exit optical system 62 is composed of one convex lens, it is not limited to this.

Further, the spherical glass 11a, 11b is in close contact with the glass substrate 6a, 6b of the liquid crystal cell 5 via the refractive index matching liquid, as in the first embodiment described above.

Next, the above-mentioned optical anisotropy measuring apparatus 60.
A method for measuring the optical anisotropy of the liquid crystal layer 7 (method for calculating the pretilt angle) using the Senarmont method according to the above will be described.

The incident light beam A emitted from the He-Ne laser device 1 passes through the polarizer 2, is converged by the incident optical system 61, passes through the spherical glass 11a, and enters the liquid crystal cell 5. The incident light flux A that has entered the liquid crystal cell 5 interacts with the liquid crystal molecules of the liquid crystal layer 7 to change the polarization state, and is normally elliptically polarized light and exits the liquid crystal cell 5.

As described above, the deflated glass 11a,
Since 11b, the glass substrates 6a and 6b, and the refractive index matching liquid (not shown) have almost the same refractive index, the incident light flux A enters the liquid crystal cell 5 without being refracted on the surface of the glass substrate 6a. Also, the absent glass 11a,
Since the center of curvature of 11b lies on the axis of rotation 8, the measurement area does not change even if the liquid crystal cell 5 is rotated (however, the size of the measurement area slightly changes).

Then, the outgoing light beam B emitted from the liquid crystal cell 5 passes through the spherical glass 11b and then exits the optical system 62.
Becomes a parallel light flux, passes through the quarter-wave plate 9 and the analyzer 3, and reaches the photodetector 4.

At this time, when the liquid crystal cell 5 rotatably supported by the rotation axis 8 which is orthogonal to the central axis of the incident light beam A and perpendicular to the paper surface is rotated rightward (direction of arrow C), for example, the liquid crystal layer The direction of the electric field vector of the incident light flux A that is incident on 7 is relatively changed. Therefore, the polarization state of the outgoing light flux B emitted from the liquid crystal cell 5 changes according to the rotation angle of the liquid crystal cell 5.

Then, the analyzer 3 is rotated in accordance with the rotation angle of the liquid crystal cell 5 to obtain the azimuth of the extinction, thereby measuring the phase difference between the ordinary ray and the extraordinary ray passing through the liquid crystal layer 7 and measuring it. From the curve plotted against the rotation angle of the cell 5, the pretilt angle of the liquid crystal molecules of the liquid crystal layer 7 can be calculated.

As described above, according to this embodiment, as shown in FIG.
Unlike the optical anisotropy measuring apparatus 210 of the conventional example shown in FIG. 4, since it has the spherical glass 11a, 11b, the measurement can be performed in the same region even if the liquid crystal cell 5 is rotated at the time of measurement. . Further, since the problems of spherical aberration and astigmatism are solved, it is possible to perform measurement in a minute area.

Further, in the conventional optical anisotropy measuring apparatus by the Senarmont method, for example, the rotation angle of the liquid crystal cell 5 is 0 to 0.
In the case of 60 degrees, the magnitude of the pretilt angle could be calculated only in the range of 0 to 13 degrees, but by using the optical anisotropy measuring device 60 according to the present embodiment, the pretilt angle can be calculated with the same rotation angle. The magnitude of the pretilt angle can be calculated within the range of 0 to 18 degrees.

Next, a seventh embodiment according to the present invention will be described with reference to FIG. The same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

The optical anisotropy measuring apparatus 70 according to this embodiment is similar to the optical anisotropy measuring apparatus 60 shown in FIG. 5 in the optical anisotropy measuring apparatus 60 shown in FIG. This is a configuration in which a ball-deficient glass holder 71 and liquid crystal cell holders 73a and 73b are provided.

The spherical glass holder 71 and the liquid crystal cell holders 73a and 73b are the optical anisotropy measuring device 5 described above.
It has the same function as 0, but has an absent glass holder 71.
Is provided so as to grip the spherical surface portions of the deflated glass 11a, 11b, and therefore the deflated glass 11a, 11b
It is not necessary to provide a flat portion on b. The optical anisotropy measuring device 70 is configured to be used for optical anisotropy measurement by the Senarmont method.

Also in this embodiment, since the spherical glass 11a, 11b is provided as in the sixth embodiment, the measurement can be performed in the same region even if the liquid crystal cell 5 is rotated during the measurement. it can. Further, since the problems of spherical aberration and astigmatism are solved, it is possible to perform measurement in a minute area.

Further, in the conventional optical anisotropy measuring apparatus by the Senarmont method, for example, the rotation angle of the liquid crystal cell 5 is 0 to 0.
In the case of 60 degrees, the magnitude of the pretilt angle could be calculated only in the range of 0 to 13 degrees, but by using the optical anisotropy measuring device 70 according to the present embodiment, the same rotation angle can be obtained. The magnitude of the pretilt angle can be calculated within the range of 0 to 18 degrees.

Next, an eighth embodiment according to the present invention will be described with reference to FIG. The same parts as those shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

In the optical anisotropy measuring apparatus 80 according to this embodiment, a flat glass plate 81 is provided between the analyzer 3 and the liquid crystal cell 5 which is the subject.

The flat glass 81 is made of a glass material having a refractive index and a thickness that are substantially the same as those of the glass substrate 6a on the incident side of the liquid crystal cell 5. The flat glass 81 is supported by a rotary shaft 82 provided in a direction perpendicular to the central axis of the incident light flux A, and is rotated by a rotary drive device 83 connected to the rotary shaft 82.

The liquid crystal cell 5 is supported by the rotary shaft 8 provided in the direction perpendicular to the central axis of the incident light beam A, and is rotated by the rotary drive device 84.

The rotation driving device 83 rotates the liquid crystal cell 5 rotated by the rotation driving device 84 (eg, arrow C ₁
The flat glass 81 is driven and controlled to rotate in the reverse direction (for example, the arrow C ₂ direction) at an angular velocity equal to the (direction).

In this way, since the rotation of the flat glass 81 is controlled, even if the liquid crystal cell 5 is rotated, the optical anisotropy of the liquid crystal layer 7 is always measured in the same region to calculate the pretilt angle. be able to.

Specifically, the incident light flux A is refracted once upon entering the flat glass 81 and upon exiting from the flat glass 81, so that the original (center of the He-Ne laser device 1 upon exiting the incident light A is emitted. It is incident on the liquid crystal layer 7 on the extension line of (axis). Thus, according to the present embodiment, the liquid crystal cell 5
It is possible to accurately measure the optical anisotropy of the liquid crystal layer 7 by eliminating the displacement of the measurement region due to the rotation of the.

Next, a ninth embodiment according to the present invention will be described with reference to FIG. The same parts as those shown in FIG. 8 are designated by the same reference numerals, and the description thereof will be omitted.

The optical anisotropy measuring apparatus 90 according to this embodiment is orthogonal to the optical axis of the incident light flux A between the polarizer 2 and the liquid crystal cell 5 and orthogonal to the optical axis of the incident light flux A. Direction, and a rotation axis 9 provided in a direction orthogonal to the rotation axis 8 of the liquid crystal cell
The second flat glass plate 91 is rotatably supported by the second flat glass plate 91. Other configurations are similar to those of the optical anisotropy measuring apparatus 80 described above.

On the rotary shaft 92 of the second flat glass plate 91,
A rotation drive device (not shown) is connected, and the second flat glass plate 91 is rotated about the rotation shaft 92 in the direction of arrow D, for example.

Then, by rotating the second flat glass plate 91, the incident light flux A emitted from the He-Ne laser device 1 is refracted in the second flat glass plate 91,
The optical axis moves in parallel. Thereby, the incident position of the incident light flux A that enters the liquid crystal cell 5 can be changed to a desired position on the axis of the rotation axis 8 of the liquid crystal cell 5.

For example, when the refractive index of the second flat glass plate 91 is 1.5 and the thickness thereof is 4.5 mm, the second flat glass plate when the incident light flux A is vertically incident on the second flat glass plate 91. When the rotation angle of 91 is 0 degree, the change amount of the measurement position in the liquid crystal cell 5 with respect to the rotation angle of the second flat glass 91 is about 1 mm at a rotation angle of 30 degrees, about 2 mm at a rotation angle of 40 degrees, and It becomes about 3 mm at 52 degrees.

Incidentally, in FIG. 9, the second flat glass plate 91 is
It is provided between the polarizer 2 and the flat glass 81,
It may be provided between the flat glass 81 and the liquid crystal cell 5.

As described above, according to the present embodiment, the second
By rotating the flat glass plate 91, the measurement position of the optical anisotropy of the liquid crystal layer 7 can be easily changed.

By changing the thickness and the refractive index of the second flat glass plate 91, the magnitude of the change in the measurement position of the liquid crystal layer 7 with respect to the rotation angle of the second flat glass plate 91 can be changed.

Further, since the uniaxial alignment treatment direction of the liquid crystal layer 7 is usually perpendicular to the rotation angle of the liquid crystal cell 5, in the present embodiment, the measurement position is changed to the direction perpendicular to the uniaxial alignment treatment direction. Is possible.

Next, a tenth embodiment of the present invention will be described with reference to FIG. The same parts as those shown in FIG. 9 are designated by the same reference numerals, and the description thereof will be omitted.

The optical anisotropy measuring apparatus 100 according to the present embodiment is arranged on the rotation axis 8 of the liquid crystal cell 5 on the central axis of the incident light flux A between the polarizer 2 and the second flat glass plate 91. In contrast, a third flat glass 101 rotatably supported by a rotary shaft 102 provided in a parallel direction is arranged. Other configurations are similar to those of the optical anisotropy measuring apparatus 90 described above.
When measuring the optical anisotropy of the liquid crystal layer 7 using the optical anisotropy measuring apparatus 100, the rotation angle of the liquid crystal cell 5 is usually 0 degree (in preparation for the measurement of the optical anisotropy. It is necessary to adjust so that the incident light flux A passes through the rotation axis 8 of the liquid crystal cell 5 in a state in which the incident light flux A is vertically incident on the glass substrate 6a on the incident side of the liquid crystal cell 5. The flat glass 101 can be adjusted, for example, by rotating the flat glass 101 in the direction of arrow E so that the incident light flux A is easily incident on the axis of the rotation axis 8 of the liquid crystal cell 5.

In FIG. 10, the third flat plate glass 101 is used.
Is provided between the polarizer 2 and the second flat glass plate 91, but is provided between the second flat glass plate 91 and the flat glass plate 81 or between the flat glass plate 81 and the liquid crystal cell 5. Good.

Further, the configurations of the optical anisotropy measuring apparatus according to each of the above-mentioned embodiments can be appropriately combined and used, whereby the optical anisotropy of the object can be measured under desired conditions. can do. For example, the flat glass 91, 101 shown in FIG. 10 may be provided between the polarizer 2 and the convex lens 31 of the optical anisotropy measuring apparatus 40 shown in FIG.

Further, as described above, the configuration of the optical anisotropy measuring apparatus according to each of the embodiments can be modified by changing a part thereof or by making it changeable.
It can also be used for optical anisotropy measurement by the crystal rotation method and optical anisotropy measurement by the Senarmont method.

The present invention is not limited to the above embodiments.

[0161]

As described above, according to the present invention,
Since the optical anisotropy of the object can be measured by suppressing the deviation of the measurement position due to the rotation of the object and by converging the incident light beam to a minute beam diameter, a liquid crystal is particularly used as the object. In such a case, it is possible to measure the unevenness in the minute region of the pretilt angle of the liquid crystal with high resolution.

[0162]

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of an optical anisotropy measuring apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of an optical anisotropy measuring apparatus according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a configuration of an optical anisotropy measuring apparatus according to a third embodiment of the present invention.

FIG. 4 is a schematic diagram showing a configuration of an optical anisotropy measuring apparatus according to a fourth embodiment of the present invention.

FIG. 5 is an enlarged schematic diagram showing a main part of an optical anisotropy measuring apparatus according to a fifth embodiment of the present invention.

FIG. 6 is a schematic diagram showing a configuration of an optical anisotropy measuring apparatus according to a sixth embodiment of the present invention.

FIG. 7 is a schematic diagram showing the configuration of an optical anisotropy measuring apparatus according to a seventh embodiment of the present invention.

FIG. 8 is a schematic diagram showing a configuration of an optical anisotropy measuring apparatus according to an eighth embodiment of the present invention.

FIG. 9 is a schematic diagram showing the configuration of an optical anisotropy measuring apparatus according to a ninth embodiment of the present invention.

FIG. 10 is a schematic diagram showing a configuration of an optical anisotropy measuring apparatus according to a tenth embodiment of the present invention.

FIG. 11 is a schematic diagram showing a configuration of an optical anisotropy measuring apparatus using a crystal rotation method according to a conventional example.

FIG. 12 is a diagram showing an example of a measurement result by an optical anisotropy measuring apparatus using a crystal rotation method.

FIG. 13 is a diagram illustrating a problem in the optical anisotropy measuring apparatus using the crystal rotation method according to the conventional example.

FIG. 14 is a schematic diagram showing a configuration of an optical anisotropy measuring apparatus using the Senarmont method according to a conventional example.

FIG. 15 is a diagram illustrating a problem in the optical anisotropy measuring apparatus using the Senarmont method according to the conventional example.

[Explanation of symbols]

1 He-Ne laser device (light source) 2 Polarizer 3 Analyzer 4 Photodetector 5 Liquid crystal cell 6a, 6b Glass substrate 7 Liquid crystal layer (subject) 9 1/4 wave plate 10, 20, 30, 40, 50, 60, 70, 80, 9
0,100 Optical anisotropy measuring device 11a, 11b Spherical glass (transparent member) 21, 31, 32 Convex lens (incident optical system) 51a, 51b Spherical portion (curved surface) 52a, 52b Flat plate portion (flat surface portion) 53, 55, 73a, 73b Liquid crystal cell holders 56, 57, 71 Spherical glass holder 61 Incident optical system 62 Output optical system 81 Flat glass (first flat transparent member) 91 Second flat glass (second flat transparent) Member) 101 Third flat glass (third flat transparent member)

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01M 11/00-11/08 G02F 1/13

Claims (14)

(57) [Claims] 1. An object having a light source that emits a light beam and a photodetector that is arranged so as to face the light source, and that is arranged between the light source and the photodetector so as to intersect with the central axis of the light beam. An optical anisotropy measuring apparatus for measuring the optical anisotropy of, a support member for rotatably supporting the subject around the direction orthogonal to the central axis as an axis, the light source and the subject A polarizer that polarizes the light flux that is disposed on the central axis between, an analyzer that polarizes the light flux that is disposed on the central axis between the subject and the photodetector, and a curved surface portion and a flat surface, respectively. A pair of transparent members arranged to face each other, and having at least a pair of transparent members for sandwiching the subject between the plane portions, the light flux polarized by the polarizer, It is made incident on the subject through the transparent member, and is emitted from the subject. Measuring the optical anisotropy of the subject by injecting the light flux into the photodetector through the analyzer and detecting a change in the polarization state of the light flux at the photodetector. Characteristic optical anisotropy measuring device. 2. A light source which emits a light beam, and a photodetector which is arranged so as to face the light source, and which is arranged between the light source and the photodetector so as to intersect with the central axis of the light beam. An optical anisotropy measuring apparatus for measuring the optical anisotropy of a sample, wherein the support member rotatably supports the sample as a first axis in a direction orthogonal to the central axis, and the light source. A polarizer arranged on the central axis between the object and the analyzer, an analyzer arranged on the central axis between the object and the photodetector, and the light between the light source and the object. A first parallel transparent member that is disposed on an axis and is rotatably supported with a direction parallel to the first axis as a second axis, and the light flux polarized by the polarizer. Through the first parallel transparent member rotated at an equal angular velocity in the opposite direction to the subject, The optical anisotropy of the subject is measured by making the light flux emitted from the subject enter the photodetector through the analyzer and detecting the change in the polarization state of the light flux at the photodetector. An optical anisotropy measuring device characterized by: 3. The optical anisotropy measuring device according to claim 1, wherein the center of curvature of the curved surface portion of the transparent member is coincident with the intersection of the central axis and the supporting member. 4. The optical anisotropy measuring apparatus according to claim 1, wherein the subject is movably arranged in any one of flat directions of the transparent member. 5. A subject having a light source that emits a light beam and a photodetector that is arranged so as to face the light source, and that is arranged between the light source and the photodetector so as to intersect the central axis of the light beam. An optical anisotropy measuring apparatus for measuring the optical anisotropy of, a support member for rotatably supporting the subject around the direction orthogonal to the central axis as an axis, the light source and the subject A polarizer that polarizes the light flux disposed on the central axis between, an incident optical system disposed on the central axis between the light source and the subject, and between the subject and the photodetector An analyzer arranged on the central axis to polarize the light flux, and a pair of transparent members facing each other, each having a curved surface portion and a flat surface portion, the pair holding the subject between the respective flat surface portions. And a transparent member disposed on the central axis between the subject and the photodetector. And an emission optical system, wherein the light beam polarized by the polarizer is incident on the subject through the incident optical system and a transparent member, and the light beam emitted from the subject is the analyzer. The optical anisotropy of the subject is measured by being incident on the photodetector through an emission optical system and detecting a change in the polarization state of the light flux at the photodetector. Anisotropy measuring device. 6. The optical anisotropy measuring device according to claim 5, wherein the focal position of the light flux converged by the incident optical system and the center of curvature of the curvature portion of the transparent member are coincident with each other. 7. The optical anisotropy measuring apparatus according to claim 5, wherein the subject is movably arranged in any one of planar directions of the transparent member. 8. The emission optical system includes a first emission optical system arranged between the subject and an analyzer for converting the light flux passing through the analyzer into a parallel light flux, and the analyzer and the light. The optical anisotropy measuring device according to claim 5, wherein the optical anisotropy measuring device includes a second emission optical system which is arranged between the detector and the photodetector and which converges the light flux into the light flux. 9. A subject having a light source that emits a light beam and a photodetector that is arranged so as to face the light source, and that is arranged between the light source and the photodetector so as to intersect the central axis of the light beam. Is an optical anisotropy measuring method for measuring the optical anisotropy of, wherein the subject is supported by a support member rotatable about a direction orthogonal to the optical axis, and the light source and the subject. And a polarizer on the central axis between, and an analyzer on the central axis between the subject and the photodetector, further facing each having a curved surface portion and a flat surface portion. The subject is sandwiched between the respective plane portions of the pair of transparent members arranged, and the light flux polarized by the polarizer is passed through the transparent member to pass through the subject. The light flux emitted from the photodetector is made incident on the photodetector through the analyzer, Optical anisotropy measuring method characterized by, measuring the optical anisotropy of the subject by detecting a change in the polarization state of the light beam in a vessel. 10. A light source that emits a light beam, and a photodetector that is arranged so as to face the light source, and an object that is arranged between the light source and the photodetector so as to intersect the central axis of the light beam. An optical anisotropy measuring method for measuring an optical anisotropy of a sample, wherein the sample is supported by a support member rotatable about a direction orthogonal to the central axis as a first axis, and A polarizer is disposed on the central axis between the light source and the subject, and an analyzer is disposed on the central axis between the subject and the photodetector, further, the light source and the subject. Rotatably supports the first parallel transparent member with the direction parallel to the first axis as a second axis, and the light flux polarized by the polarizer is equal to the direction opposite to the subject. The light flux emitted from the subject is passed through the first parallel transparent member that is rotated at an angular velocity. The optical anisotropy of the subject is measured by being incident on the photodetector through an analyzer and detecting a change in the polarization state of the light flux at the photodetector. How to measure the orientation. 11. An object having a light source for emitting a light beam and a photodetector arranged to face the light source, the object being arranged between the light source and the photodetector so as to intersect with the central axis of the light beam. Is an optical anisotropy measuring method for measuring the optical anisotropy of, wherein the subject is supported by a support member rotatable about a direction orthogonal to the central axis, and the light source and the subject. While arranging a polarizer on the central axis between and, disposing an analyzer on the central axis between the subject and the photodetector,
Further, the subject is sandwiched between the respective flat portions of a pair of transparent members which are arranged to face each other, each having a curved surface portion and a flat portion, and is incident on the central axis between the light source and the subject. An optical system is arranged, an emission optical system is arranged on the central axis between the subject and a photodetector, and the light flux polarized by the polarizer is passed through the incident optical system and a transparent member. Passing through the inside of the subject, making the speed of light emitted from the subject enter the photodetector through the emission optical system and the analyzer, and detecting the change in the polarization state of the light flux by the photodetector. The optical anisotropy of the subject is measured by the method. 12. An incident optical system having a positive power is arranged on the central axis between the light source and the subject, and the light flux is converged by the incident optical system to be incident into the subject. The optical anisotropy measuring method according to claim 9 or 10. 13. The optical anisotropy measuring method according to claim 11, wherein the focal position of the light beam converged by the incident optical system and the center of curvature of the curved surface portion of the transparent member coincide with each other. 14. The optical anisotropy measuring method according to claim 11, wherein the subject is movably arranged in any one of the plane directions of the transparent member.