JP3936712B2 - Parameter detection method and detection apparatus for detection object - Google Patents

Description

  The present invention relates to a detection target parameter detection method and a detection apparatus that detect a detection target parameter (retardation or thickness of a liquid crystal layer to be detected) having birefringence characteristics.

As a liquid crystal display element (hereinafter referred to as “liquid crystal cell”) constituting a liquid crystal display device, a liquid crystal cell in which the major axis direction of liquid crystal molecules is aligned in a direction substantially parallel to the substrate surface, for example, twisted nematic (Twisted Nematic (TN) type, Super Twisted Nematic (STN) type, IPS (In-Plane Switching) type liquid crystal cell, or the direction in which the major axis direction of the liquid crystal molecules is substantially parallel to the normal of the substrate surface, A liquid crystal cell (hereinafter referred to as “VA cell”) that is aligned in a direction substantially perpendicular to the substrate surface (Vertical Alignment; VA) is known.
VA cells are widely used in liquid crystal televisions, liquid crystal monitors and the like because they have a high contrast ratio and a wide viewing angle.
The display performance of the liquid crystal cell greatly depends on the thickness of the liquid crystal layer of the liquid crystal cell. For this reason, management of the thickness of the liquid crystal layer of the liquid crystal cell is important.
The thickness of the liquid crystal layer of the liquid crystal cell is obtained by detecting the retardation of the liquid crystal layer represented by the product of the thickness of the liquid crystal layer of the liquid crystal cell and the birefringence, and dividing the detected retardation of the liquid crystal layer by the birefringence. Can be sought.
The retardation of the liquid crystal layer of the liquid crystal cell in which the major axis direction of the liquid crystal molecules is aligned in a direction substantially parallel to the substrate surface is such that light is incident perpendicularly to the substrate surface of the liquid crystal cell and transmitted through the liquid crystal cell. It can be detected by analyzing the polarization state.
However, in the VA cell, the major axis direction of the liquid crystal molecules is aligned in a direction perpendicular to the substrate surface. Therefore, even if light is incident perpendicularly to the substrate surface of the VA cell, the liquid crystal molecules behave optically isotropically, so that the polarization state of the light transmitted through the VA cell does not change. That is, it is not possible to use a method in which light is incident perpendicularly to the substrate surface of the VA cell.
Therefore, a method has been proposed in which the thickness of the liquid crystal layer of the VA cell is detected by analyzing the polarization state of the light that is incident obliquely on the substrate surface of the VA cell and transmitted through the VA cell. (See Non-Patent Document 1, Non-Patent Document 2, and Patent Document 1)
Hiap Lee Ong, Journal of Applied Physics, Vol. 71, No. 1, 1992, pages 140-144 Hiap Lee Ong, Journal of Applied Physics, Vol. 70, No. 4, 1991, pages 2023-2030 International Publication No. WO01 / 022029

［式１］ For example, in the method described in Patent Document 1, a measurement system in which each element is arranged in the order of a light emitting device, a polarizer, an analyzer, and a detection device is used. When detecting the retardation of the detection target, first, the detection target is placed between the polarizer and the analyzer. Next, the transmitted light when the transmission axis direction of the polarizer and the transmission axis direction of the analyzer are made parallel with the slow axis of the detection target oriented at 45 ° with respect to the transmission axis direction of the polarizer The intensity (detection signal of the detection device) I _para and the transmitted light intensity I _cross when the transmission axis direction of the polarizer and the transmission axis direction of the analyzer are orthogonal to each other are measured. Then, using the measured transmitted light intensity _{I para} and _{I cross,} by [Equation 1] to obtain the retardation R of the detection object.

[Formula 1]

When light is incident parallel to the normal of the substrate surface of the liquid crystal cell, that is, perpendicular to the substrate surface of the liquid crystal cell, the light transmittance at the interface (for example, the air-glass interface) is It does not change with the polarization direction. That is, the transmittance does not depend on the polarization direction.
However, when light is incident obliquely on the substrate surface of the liquid crystal cell, the light transmittance at the interface varies depending on the polarization direction of the incident light. That is, the polarization direction dependency of the transmittance occurs.
For this reason, when detecting the retardation of the liquid crystal layer of the VA cell using a method in which light is incident obliquely on the substrate surface of the VA cell, the transmittance of the VA cell is increased in order to increase the detection accuracy of the retardation of the liquid crystal layer of the VA cell. It is necessary to consider polarization direction dependency.
In the method described in Patent Document 1, the retardation of the liquid crystal layer cannot be accurately detected because the dependency of the transmittance on the polarization direction is not taken into consideration. Therefore, the thickness of the liquid crystal layer cannot be accurately detected.
In the method described in Patent Document 1, the average value of the ordinary light refractive index and the extraordinary light refractive index is used as the birefringence. The thickness of the liquid crystal layer can be obtained by dividing the detected retardation of the liquid crystal layer by the birefringence, but since the average value is an approximate value, in the method described in Patent Document 1, the thickness of the liquid crystal layer is It cannot be detected accurately.
Non-Patent Document 2 described above describes a method that considers the polarization direction dependency of transmittance, but only considers the transmittance at the air-glass interface. Here, the actual liquid crystal cell is provided with a glass substrate, a color filter, a transparent electrode, and the like. In order to know the transmittance of the liquid crystal cell, it is necessary to grasp in advance the transmittance of all the members of the liquid crystal cell, which is not realistic. Furthermore, since the optical characteristics such as the refractive index of the thin film material change depending on the conditions for forming the film, it is difficult to grasp the transmittance in advance. For this reason, even if the method described in Non-Patent Document 2 is applied, the retardation of the liquid crystal layer cannot be accurately detected.
Non-Patent Document 1 described above describes a method capable of accurately detecting the retardation of the liquid crystal layer without considering the polarization direction dependency of the transmittance. However, since the condition that the light transmittance is minimized is used, the retardation of the liquid crystal layer cannot be accurately detected when the retardation is distributed in the measurement region.
Therefore, the problem to be solved by the present invention is to provide a parameter detection method and a detection apparatus for a detection target that can easily and accurately detect parameters such as retardation and thickness of the detection target.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a case where light is incident obliquely on a substrate surface to be detected, and parameters of the detection target (retardation or thickness of the liquid crystal layer to be detected) are detected using the intensity of light that has passed through the detection target Can be used.
  The detection target includes an element having birefringence characteristics such as a VA cell.
  The “incident surface” is a surface including the traveling direction of linearly polarized light incident on the detection target substrate surface and the normal line of the detection target substrate surface.
  The first invention of the present invention is a parameter detection method of a detection object as described in claim 1.
  In the parameter detection method of the detection target according to claim 1, linearly polarized light whose polarization direction is inclined at an arbitrary angle α with respect to the incident surface is incident on the detection target, and the transmission axis direction of the analyzer is relative to the incident surface. Any angle ω ₁ Transmitted light intensity I (ω when tilted ₁ , Α) and the angle of the transmission axis of the analyzer with respect to the incident surface ω ₂ (= Ω ₁ Transmitted light intensity I (ω when tilted at + 90 °) ₂ , Α) and the angle of the transmission axis of the analyzer with respect to the incident surface ω ₃ (= Ω ₁ Transmitted light intensity I (ω when tilted + 45 °) ₃ , Α).
  Then, the detected transmitted light intensity I (ω ₁ , Α), I (ω ₂ , Α), I (ω ₃ , Α), the retardation R to be detected is obtained by the following equation.

  The second invention of the present invention is a parameter detection method of a detection object as described in claim 2.
  In the parameter detection method of the detection target according to claim 2, linearly polarized light whose polarization direction is inclined at an arbitrary angle α with respect to the incident surface is incident on the detection target, and the transmission axis direction of the analyzer is relative to the incident surface. Any angle ω ₁ Transmitted light intensity I (ω when tilted ₁ , Α) and the angle of the transmission axis of the analyzer with respect to the incident surface ω ₂ (= Ω ₁ Transmitted light intensity I (ω when tilted at + 90 °) ₂ , Α) and the angle of the transmission axis of the analyzer with respect to the incident surface ω ₄ (= Ω ₁ + 135 °) Transmitted light intensity I (ω ₄ , Α).
  Then, the detected transmitted light intensity I (ω ₁ , Α), I (ω ₂ , Α), I (ω ₄ , Α), the retardation R of the detection target is obtained by the following equation.

  The third invention of the present invention is a parameter detection method of a detection object as described in claim 3.
  In the parameter detection method of the detection target according to claim 3, the transmission axis direction of the analyzer is tilted at an arbitrary angle ω with respect to the incident surface, and the polarization direction is at an arbitrary angle α with respect to the incident surface. ₁ Transmitted light intensity I (ω, α when tilted linearly polarized light is incident on the detection target ₁ ) And the angle α ₂ (= Α ₁ Intensity of transmitted light I (ω, α) when linearly polarized light inclined at + 90 ° is incident on the detection target ₂ ) And the angle α ₃ (= Α ₁ Transmitted light intensity I (ω, α) when linearly polarized light that is tilted at + 45 ° is incident on the detection target ₃ ) Is detected.
  Then, the detected transmitted light intensity I (ω, α ₁ ), I (ω, α ₂ ), I (ω, α ₃ ) To obtain the retardation R to be detected by the following equation.

  The fourth invention of the present invention is a parameter detection method of a detection object as described in claim 4.
  In the parameter detection method of the detection target according to claim 4, the transmission axis direction of the analyzer is inclined at an arbitrary angle ω with respect to the incident surface, and the polarization direction is an angle α with respect to the incident surface. ₁ Transmitted light intensity I (ω, α when tilted linearly polarized light is incident on the detection target ₁ ) And the angle α ₂ (= Α ₁ Intensity of transmitted light I (ω, α) when linearly polarized light inclined at + 90 ° is incident on the detection target ₂ ) And the angle α ₄ (= Α ₁ Transmitted light intensity I (ω, α) when linearly polarized light that is tilted to + 135 ° is incident on the detection target ₄ ) Is detected.
  Then, the detected transmitted light intensity I (ω, α ₁ ), I (ω, α ₂ ), I (ω, α ₄ ) To obtain the detection target retardation R by the following equation.

  A fifth aspect of the present invention is a parameter detection method for a detection target as described in claim 5.
  In the detection target parameter detection method according to the fifth aspect, the thickness d of the detection target is obtained based on the retardation R of the detection target.
  As a method for obtaining the thickness d of the detection target based on the retardation R of the detection target, a method of dividing the retardation R of the detection target by the birefringence of the detection target can be used.
  A sixth aspect of the present invention is a parameter detection apparatus as a detection target as described in the sixth aspect.
  According to a sixth aspect of the present invention, there is provided a detection target parameter detection apparatus including a light emitting device, a polarizer, a detection target, an analyzer, a detection device, and a processing device.
  As the light emitting device, a light emitting device that emits monochromatic light is used.
  The polarizer and the analyzer can rotate with the transmission axis direction as an axis of rotation parallel to the light traveling direction. As the drive mechanism for rotating the polarizer and the analyzer, a manual drive mechanism for manually rotating the polarizer or the analyzer can be used, or the drive for rotating the polarizer or the analyzer by a drive source such as an electric motor. A mechanism can also be used. Furthermore, when detecting the intensity of each transmitted light, the driving source provided in the driving mechanism of the polarizer or the analyzer can be controlled by the processing device.
  The detection target is arranged so that light transmitted through the analyzer is incident at an angle inclined with respect to the normal of the substrate surface. For example, it is possible to use a method in which the support portion that supports the analyzer is arranged to be inclined with respect to the light incident direction, or a method in which the support portion is rotated by a driving mechanism.
  The detection device detects the intensity of light transmitted through the analyzer as transmitted light intensity.
  A processing apparatus inputs the transmitted light intensity detected by the detection apparatus, and calculates | requires the retardation R and thickness d of a detection target using the method in any one of Claims 1-6.

  If the parameter detection method for a detection target according to any one of claims 1 to 4 is used, since the dependence of the transmittance on the polarization direction due to oblique incidence of light on the detection target is taken into consideration, the detection target is tilted. Even when light is incident on, the parameter to be detected can be accurately detected. Moreover, since it is not necessary to grasp the refractive index and transmittance of each member, the processing is simple.
  According to the parameter detection method of the detection target according to the fifth aspect, the thickness of the liquid crystal layer to be detected can be detected easily and accurately.
  If the detection target parameter detection apparatus according to the sixth aspect is used, the detection target parameter can be easily and accurately detected with a simple configuration.
  Moreover, since the parameter detection method of the detection target according to claims 1 to 5 and the parameter detection apparatus of the detection target according to claim 6 can be used to determine the parameter of the detection target by calculation from the transmitted light intensity, Even when the detection target parameter is distributed in the measurement region, the distribution can be easily obtained.

Hereinafter, embodiments of the present invention will be described.
In the following description, a VA cell in which the major axis direction of the liquid crystal molecules is aligned in a direction parallel to the normal line of the substrate surface, that is, in a direction perpendicular to the substrate surface, is detected. A case where the retardation or thickness of a certain liquid crystal layer is detected will be described.
It is assumed that the layers other than the liquid crystal layer of the VA cell are isotropic and have no retardation. Further, even when a target other than the liquid crystal cell is to be detected, only one layer having retardation is provided. However, when the slow axis is in the plane of incidence and the total retardation is the sum of the retardations of each layer, all these layers are considered as one layer.

First, FIG. 1 shows a parameter detection device to be detected (hereinafter simply referred to as “parameter detection device”) used in the following embodiment. A coordinate system of the parameter detection apparatus shown in FIG. 1 is shown in FIG.
In FIG. 1, the left-right direction of the paper surface is the x-axis (right direction is positive), the vertical direction of the paper surface is z-axis (upward direction is positive), and the direction perpendicular to the paper surface is y-axis (the back side of the paper surface is positive). . The light traveling direction is the positive direction of the z-axis, and a right-handed coordinate system in which the x-axis exists in the incident plane is used.
In the present specification, the “incident surface” means a surface including the traveling direction of incident light and the normal line of the substrate surface of the VA cell 12, and corresponds to the paper surface in FIG.
The direction of the transmission axis of the polarizer and analyzer and the direction of the linearly polarized light of the incident light are specified by a rotation angle in the xy plane, the positive direction of the x axis is 0 °, and the positive direction of the x axis is the positive direction of the y axis. The direction of rotation toward is positive.

The parameter detection device shown in FIG. 1 includes a light emitting device 10, a polarizer 11, a VA cell 12, an analyzer 13, a detection device 14, and a processing device 15. Each device is disposed along the traveling direction of light emitted from the light emitting device 10 (the z-axis direction in FIG. 1).
The light emitting device 10 emits monochromatic light for parameter detection. The light emitting device 10 can be configured by a light source (for example, a laser) that emits monochromatic light. In addition, the light emitting device 10 includes a multicolor light source (for example, a halogen lamp) that irradiates multicolor light in a certain wavelength range and a monochromizing unit (for example, a spectroscope or an interference filter) that monochromatically multicolor light. You can also.
The polarizer 11 transmits only linearly polarized light in the transmission axis direction from the light emitted from the light emitting device 11. The analyzer 13 transmits only the linearly polarized light in the transmission axis direction from the light transmitted through the VA cell 12. As the polarizer 11 and the analyzer 13, a polarizing prism such as a Glan-Thompson prism or a polarizing film such as a Polaroid (registered trademark) film can be used.
The polarizer 11 and the analyzer 13 are arranged such that the transmission axis direction is rotatable in the xy plane with an axis parallel to the light traveling direction (z axis) as a rotation axis. For example, the polarizer 11 and the analyzer 13 are supported by a support portion that is rotated by the drive mechanisms 11a and 13a. As the drive mechanisms 11a and 13a, a manual drive mechanism that manually rotates the support portion or a drive mechanism that rotates the support portion with a drive source such as a stepping motor can be used. Further, the drive source may be controlled by a manual switch or by the processing circuit 15. If it is configured to be controllable by the processing device 15, the work can be automated and the work time can be shortened.

The detection target 12 is arranged so that light is incident obliquely. For example, the support part that supports the detection target 12 is arranged in a state inclined with respect to the traveling direction of the incident light. Alternatively, a support portion that is rotatable about an axis parallel to the y axis (in FIG. 1, the front and back direction of the paper surface) is provided. The support portion is driven manually or by a drive source by the drive mechanism 12a. If the drive source is configured to be controllable by the processing device 15, the work can be automated and the work time can be shortened.
If the liquid crystal molecules are aligned parallel to the normal line of the substrate surface of the VA cell, the slow axis (the long axis direction of the liquid crystal molecules) of the liquid crystal layer is always set when the VA cell 12 is arranged as shown in FIG. Included in the entrance surface. If the liquid crystal molecules are tilted with respect to the normal of the substrate surface of the VA cell, or the slow axis is not parallel to the normal of the surface even if the object to be detected is not a liquid crystal cell, It is assumed that the detection target is arranged so that the slow axis direction is included in the incident surface.
The drive mechanisms 11a, 12a, and 13a are preferably provided with rotational position detectors that can detect or determine the rotational positions of the polarizer 11, the detection target 12, and the analyzer 13.
As the detection device 14, a device that outputs a signal proportional to the intensity of incident light, such as a photodiode or a photomultiplier tube, as a detection signal is used. If the detection signal is not proportional to the intensity of the incident light, the relationship between the detection signal and the intensity of the incident light is obtained in advance, and correction is performed so that the detection signal is proportional to the intensity of the incident light.

［式２］
ここで、Ｅ_０ ^ｐ、Ｅ_０ ^ｓは、ｐ偏光及びｓ偏光の電場の大きさである。Ｅ_０は、入射光の電場ベクトルの大きさ（振幅）である。ｐ偏光とは入射面で振動する直線偏光であり、ｓ偏光とは入射面とは直交する方向（つまりｐ偏光と直交する方向）に振動する直線偏光である。＜ｅ_０ ^ｐ＞、＜ｅ_０ ^ｓ＞は、ｐ偏光及びｓ偏光の偏光方向の単位ベクトルである。ＶＡセル１２に入射する前であるため、＜ｅ_０ ^ｐ＞及び＜ｅ_０ ^ｓ＞は、それぞれｘ軸及びｙ軸に平行である。 The light emitted from the light emitting device 10 becomes linearly polarized light in the direction of the angle α by the polarizer 11 whose transmission axis direction is inclined in the direction of the angle α with respect to the incident surface.
When the linearly polarized light transmitted through the polarizer 11 enters the substrate surface of the VA cell 12, it propagates separately into s-polarized light and p-polarized light. The s-polarized light is linearly polarized light in a direction perpendicular to the incident surface, and the p-polarized light is linearly polarized light in a direction parallel to the incident surface.
An electric field vector <E ₀ > of linearly polarized light before entering the VA cell 12 is expressed by [Expression 2]. In this specification, [<>] is used as a symbol representing a vector.

[Formula 2]
Here, E ₀ ^p and E ₀ ^s are the magnitudes of the electric fields of p-polarized light and s-polarized light. E ₀ is the magnitude (amplitude) of the electric field vector of the incident light. The p-polarized light is linearly polarized light that vibrates on the incident surface, and the s-polarized light is linearly polarized light that vibrates in a direction orthogonal to the incident surface (that is, a direction orthogonal to p-polarized light). <E ₀ ^p > and <e ₀ ^s > are unit vectors in the polarization direction of p-polarized light and s-polarized light. Since it is before entering the VA cell 12, <e ₀ ^p > and <e ₀ ^s > are parallel to the x-axis and the y-axis, respectively.

［式３］
ここで、ｔ_１０ ^ｐ、ｔ_１０ ^ｓは、ｐ偏光及びｓ偏光に対する振幅透過率である。 The electric field vector <E ₁ > immediately after passing through the interface is expressed by [Expression 3].

[Formula 3]
Here, t ₁₀ ^p and t ₁₀ ^s are amplitude transmittances for p-polarized light and s-polarized light.

［式４］ Since refraction occurs at the interface, <e ₁ ^p > ≠ <e ₀ ^p >, and <e ₁ ^p > is not parallel to the x axis, but is included in the xz plane. On the other hand, <e ₁ ^s > = <e ₀ ^s >, which remains parallel to the y-axis.
If attention is paid only to the magnitude of each polarization component, the electric field amplitude of the light after passing through the first interface is expressed by [Equation 4].

[Formula 4]

［式５］ Changes in the electric field of light at other interfaces such as the glass-color filter interface and the transparent electrode-alignment film interface can be described in the same manner.
Now, consider the i-th interface, with the interface on the incident side air-cell outermost surface as the first interface. Here, the i-th interface is an interface between the [i−1] -th medium (0th is incident-side air) and the i-th medium.
If <e _i ^p > and <e _i ^s > are unit vectors in the polarization direction of p-polarized light and s-polarized light in the i-th medium, the electric field vector <E _i > in the i-th medium is expressed by ].

[Formula 5]

［式６］
ここで、ｔ_{ｉ＋１，ｉ} ^ｐ、ｔ_{ｉ＋１，ｉ} ^ｓは、ｉ番目の界面でのｐ偏光及びｓ偏光に対する振幅透過率である。 The electric field vector <E _{i + 1} > immediately after passing through the i-th interface is expressed by [Expression 6].

[Formula 6]
^{_{Here, t i + 1, i p}} , t i + 1, i s is the amplitude transmittance for p-polarized light and s-polarized light at the i-th surface.

［式７］
［式７］は大きさだけに注目しているが、偏光状態を記述するには、ｓ偏光とｐ偏光の間の相対的な位相差も考慮する必要がある。
ここでは、液晶層以外は光学的に等方と想定しているため、ｓ偏光とｐ偏光の間に位相差は発生しない。つまり、位相差まで考慮しても、［式７］により光の透過を記述することができる。 Since refraction occurs at the interface, <e _{i + 1} ^p > ≠ <e _i ^p >, and <e _{i + 1} ^p > is not parallel to the x-axis, but is included in the xz plane. On the other hand, <e _{i + 1} ^s > = <e _i ^s > = <e ₀ ^s >, which remains parallel to the y-axis.
If attention is paid only to the magnitude of each polarization component, the amplitude of the electric field of light after passing through this interface is expressed by [Equation 7].

[Formula 7]
[Equation 7] focuses only on the magnitude, but to describe the polarization state, it is necessary to consider the relative phase difference between s-polarized light and p-polarized light.
Here, since it is assumed that other than the liquid crystal layer is optically isotropic, no phase difference is generated between the s-polarized light and the p-polarized light. That is, light transmission can be described by [Equation 7] even when the phase difference is taken into consideration.

In the liquid crystal, light propagates separately into ordinary light and abnormal light. However, as shown in FIG. 1, when the slow axis exists on the incident surface, ordinary light is s-polarized light, that is, linearly polarized light in a direction perpendicular to the incident surface, and extraordinary light is p-polarized light, That is, it is linearly polarized light in a direction orthogonal to s-polarized light within the incident plane.
Accordingly, the s-polarized light that has propagated through each medium such as glass constituting the VA cell 12 propagates as it is in ordinary light, and the p-polarized light propagates in the liquid crystal as extraordinary light. For this reason, the transmittance at the interface of the liquid crystal layer can also be expressed in the same format as [Formula 7].

［式８］
ここで、ｄは液晶層の厚さであり、λは入射光の波長である。 However, the liquid crystal layer exhibits anisotropy and has retardation. That is, the refractive index differs depending on the polarization direction, and a phase difference occurs between ordinary light and extraordinary light (s-polarized light and p-polarized light).
A liquid crystal layer and l-th medium, the refractive index n _o ^eff of ^ordinary, and the refractive index of the extraordinary light and n _e ^eff, passes through the liquid crystal layer, [l + 1] -th field just before the light enters a medium The components E _l ^p and E _l ^s of the vector <E _l > are represented by [Equation 8].

[Formula 8]
Here, d is the thickness of the liquid crystal layer, and λ is the wavelength of incident light.

［式９］
ここで、Θは、入射光とＶＡセル表面の法線との間の角度である（図１、図２参照）。θは、ＶＡセル表面の法線と液晶層の遅相軸の間の角度である。ｎ_ｅ、ｎ_ｏは、液晶材料の屈折率であり、電場が液晶分子の長軸方向に平行な方向及び直交する方向の直線偏光に対するものである。
ＶＡセルの場合、液晶分子の長軸方向はＶＡセル表面の法線に平行（基板面に垂直）に配向されているため、θ＝０である。
従って、［式９］は［式１０］となる。

［式１０］ n _o ^eff and n _e ^eff are expressed by [Expression 9].

[Formula 9]
Here, Θ is an angle between the incident light and the normal line of the VA cell surface (see FIGS. 1 and 2). θ is an angle between the normal line of the VA cell surface and the slow axis of the liquid crystal layer. n _e and n _o are the refractive indices of the liquid crystal material, and are for linearly polarized light whose electric field is parallel to and orthogonal to the major axis direction of the liquid crystal molecules.
In the case of the VA cell, θ = 0 because the major axis direction of the liquid crystal molecules is aligned parallel to the normal line of the VA cell surface (perpendicular to the substrate surface).
Therefore, [Equation 9] becomes [Equation 10].

[Formula 10]

［式１１］
ここで、ｔ_ｐ、ｔ_ｓは、ｐ偏光及びｓ偏光に対するＶＡセル全体の振幅透過率であり、［式１２］で表される各界面での振幅透過率の積である。

［式１２］ The light that has passed through the liquid crystal layer passes through the interface between the isotropic media several times thereafter, and finally exits to the outside of the VA cell, that is, to the air.
The change in the polarization state of incident light due to the above process is as follows. When the electric field vector of the emitted light is <E _m > (assuming that there are [m + 1] medium layers including air on both sides of the liquid crystal layer and the VA cell) , <E _m > is represented by [Formula 11].

[Formula 11]
Here, t _p and t _s are amplitude transmittances of the entire VA cell with respect to p-polarized light and s-polarized light, and are products of amplitude transmittance at each interface expressed by [Equation 12].

[Formula 12]

［式１３］
ここで、Ｉ_０は、検光子１３の透過率で規格化した出射光の強度である。Ｔ_ｐ＝ｔ_ｐ ^２、Ｔ_ｓ＝ｔ_ｓ ^２は、ｐ偏光、ｓ偏光に対するＶＡセル１２の透過率である。Δｎ^ｅｆｆ＝ｎ_ｅ ^ｅｆｆ−ｎ_ｏ ^ｅｆｆは、ＶＡセル１２の液晶層の複屈折率である。また、［Ｒ＝Δｎ^ｅｆｆ・ｄ］は、ＶＡセル１２の液晶層のリタデーションである。 The intensity I (ω, α) of the emitted light is detected by the detection device 14 through the analyzer 13 whose transmission axis is oriented in the direction of the angle ω (the transmission axis direction is inclined at the angle ω with respect to the incident surface). In the case of detection, I (ω, α) is expressed by [Equation 13].
In this specification, I (ω, α) is the direction of polarization of incident light (transmission axis direction of the polarizer 11) in the direction of an angle α from the incident surface, and the transmission axis direction of the analyzer 13 is the incident surface. The transmitted light intensity (detection signal of the detection device 14) when directed from the angle to the direction of the angle ω is shown.

[Formula 13]
Here, I ₀ is the intensity of the outgoing light normalized by the transmittance of the analyzer 13. T _p = t _p ² and T _s = t _s ² are transmittances of the VA cell 12 for p-polarized light and s-polarized light. ^{_{Δn eff = n e eff -n o}} eff is the birefringence of the liquid crystal layer of the VA cell 12. [R = Δn ^eff · d] is a retardation of the liquid crystal layer of the VA cell 12.

The retardation R of the liquid crystal layer can be obtained by analyzing the retardation R of the liquid crystal layer as a variable by [Equation 13] using the transmitted light intensity detected by the detection device 14.
Here, [Formula 13] includes the transmittances T _p and T _s of the VA cell 12 for p-polarized light and s-polarized light. Therefore, in order to obtain the retardation of the liquid crystal layer from [Equation 13] using the transmitted light intensity, specific values of the transmittances T _p and T _s of the VA cell 12 are necessary.
However, in order to obtain specific values of the transmittances T _p and T _s of the VA cell 12 in advance, it is necessary to grasp the transmittances of all the members of the VA cell 12 in advance. The actual VA cell 12 has members such as ITO transparent electrodes and color filters, and it is not practical to know the transmittance of all members in advance. Moreover, since the optical characteristics such as the refractive index of the thin film member change depending on the film manufacturing conditions, it is not practical to grasp the thin film member in advance.
In the present invention, the transmittance T _p of the VA cell _12, without requiring the value of T _s, the retardation R of the liquid crystal layer, therefore, proposes an analysis method capable of accurately detecting the thickness d of the liquid crystal layer To do.

Hereinafter, an embodiment of a method for detecting a parameter to be detected (in this embodiment, retardation R and thickness d of the liquid crystal layer of the VA cell 12) using the parameter detection apparatus shown in FIGS. 1 and 2 will be described. Will be explained.
[First Embodiment]
In the first embodiment, an inclination angle ω in the transmission axis direction of the analyzer 13 with respect to the incident surface (hereinafter referred to as “transmission axis direction ω of the analyzer 13”) is set to an arbitrary angle, and the polarizer with respect to the incident surface. Transmitted light when the inclination angle α in the transmission axis direction of 11 (hereinafter referred to as “transmission axis direction α of the polarizer 11”) is parallel (α = 0 °) and orthogonal (α = 90 °) to the incident surface. The parameter of the VA cell 12 (detection target) is detected using the intensity ratio r.

［式１４］ The transmission axis direction ω of the analyzer 13 is set to an arbitrary angle ω ₀ (the transmission axis direction of the analyzer 13 is directed to the direction of the angle ω ₀ ), and the transmission axis direction α of the polarizer 11 is set to 0 °. The transmitted light intensity (detection signal of the detection device 14) when the transmission axis direction of the polarizer 11 is directed to 0 ° is I (ω ₀ , 0 °).
Further, the transmission axis direction ω of the analyzer 13 is set to the above-mentioned arbitrary angle ω _0, and the transmitted light intensity when the transmission axis direction α of the polarizer 11 is set to 90 ° is I (ω ₀ , 90 ° ).
Then, using the transmitted light intensity I (ω ₀ , 0 °) and I (ω ₀ , 90 °), the ratio r is obtained by [Equation 14].

[Formula 14]

［式１５］
ここで、偏光子１１の透過軸方向αと検光子１３の透過軸方向ωのすくなくとも一方が異なる、少なくとも２つ以上の組み合わせ（相異なる少なくとも２つ以上の組み合わせ）に対する透過光強度、例えば、任意の角度α_１と任意の角度ω_１の組み合わせ(ω_１，α_１)に対する透過光強度Ｉ(ω_１，α_１)と、任意の角度α_２と任意の角度ω_２の組み合わせ(ω_２，α_２)に対する透過光強度Ｉ(ω_２，α_２)との比は、[式１６]で表される。

［式１６］
なお、(ω，α)の相異なる組み合わせの選択方法としては、αのみが異なる組み合わせ、例えば、(ω_１，α_１)の組み合わせと(ω_１，α_２)の組み合わせを選択する方法や、ωのみが異なる組み合わせ、例えば、(ω_１，α_１)の組み合わせと(ω_２，α_１)の組み合わせを選択する方法を用いることができる。ω_１≠ω_２、α₁≠α_２でも構わない。 The transmitted light intensity I (ω, α) when the transmission axis direction of the polarizer 11 is set to an arbitrary angle α and the transmission axis direction of the analyzer 13 is set to an arbitrary angle ω is the ratio r of [Equation 14]. And is represented by [Equation 15].

[Formula 15]
Here, the transmitted light intensity with respect to at least two or more combinations (at least two or more different combinations) in which at least one of the transmission axis direction α of the polarizer 11 and the transmission axis direction ω of the analyzer 13 is different, for example, arbitrary angle alpha ₁ and any combination of angles _{ω 1 (ω 1, α 1} ) the transmitted light intensity I (ω _{1, α 1)} with respect to a, any angle alpha ₂ and combinations of any angle omega ₂ (omega _2, transmitted light intensity I (omega ₂ for alpha _2), the ratio of the alpha ₂₎ is represented by [expression 16].

[Formula 16]
In addition, as a method for selecting different combinations of (ω, α), a method in which only α is different, for example, a method of selecting a combination of (ω ₁ , α ₁ ) and a combination of (ω ₁ , α ₂ ), A combination in which only ω is different, for example, a method of selecting a combination of (ω ₁ , α ₁ ) and a combination of (ω ₂ , α ₁ ) can be used. ω ₁ ≠ ω ₂ and α ₁ ≠ α ₂ may be used.

[Expression 16] does not include the transmittances T _p and T _s of the liquid crystal layer of the VA cell 12. Further, α ₁ , α ₂ , ω ₀ , ω ₁ , ω ₂ are known, and the wavelength λ of the incident light is also known. That is, in [Expression 16], the only variable is the retardation R of the liquid crystal layer of the VA cell 12.
Therefore, I (ω _1, α ₁₎ and I (ω _2, α ₂₎ is detected (measured) by the detection device 14, detection (measurement) the I (ω _1, α ₁₎ and I (omega _2, alpha ₂ ), the retardation R of the liquid crystal layer of the VA cell 12 can be obtained by [Expression 16].
It is to be noted that [the retardation R of the liquid crystal layer = Δn ^eff · d], and the birefringence Δn ^eff of the liquid crystal layer is the normal light with respect to the normal light of the liquid crystal layer, as shown in [Expression 9] and [Expression 10]. represented by extraordinary refractive index n _e for the refractive index n _o and extraordinary light.
Therefore, the thickness R of the liquid crystal layer of the VA cell 12 is obtained by dividing the retardation R of the liquid crystal layer of the VA cell 12 obtained by [Equation 16] by the birefringence Δn ^eff of the liquid crystal layer of the VA cell 12. be able to.
In the above, the specific value of the ratio r was obtained by [Equation 14]. However, it is not necessary to obtain a specific value of r by using a formula in which [Formula 14] is substituted for r in [Formula 15] or [Formula 16].
Further, the unknown variables in [Expression 15] are the retardation R and the coefficient I ₀ · T _p . For this reason, the transmitted light intensity I (ω, α) when the transmission axis direction of the analyzer 13 is inclined at an arbitrary angle ω with respect to the incident surface and the polarization direction is inclined at an arbitrary angle α with respect to the incident surface, Detection is performed for at least two or more combinations of ω and α (ω, α) in which at least one of ω or α is different, and the detected transmitted light intensity I (ω, α) is calculated by [Equation 15] and By comparing, the retardation R of the liquid crystal layer can be obtained. For the comparison, for example, a least square method can be used.

The procedure of this embodiment will be described below.
(Step 1)
The VA cell 12 is installed in the parameter detection apparatus shown in FIG. 1 at an angle Θ with respect to the traveling direction of incident light.
For example, the VA cell 12 is disposed on a support (not shown) of the parameter detection apparatus shown in FIG. Then, the drive unit 12a rotates the support portion about the axis parallel to the y axis as the rotation axis, and sets the angle between the traveling direction of the incident light (z axis direction) and the normal direction of the substrate surface of the VA cell 12. Set to Θ.
Alternatively, the VA cell 12 is supported (arranged) on a support portion inclined at an angle Θ with respect to the traveling direction of incident light. In this case, the driving device 12a can be omitted.

［式１７］ (Step 2)
Transmitted light intensity I ^m (ω ₀ , 0 °) when the transmission axis direction of the polarizer 11 is directed to 0 ° with the transmission axis direction of the analyzer 13 directed to an arbitrary angle ω ₀ Then, the transmitted light intensity I ^m (ω ₀ , 90 °) when the transmission axis direction of the polarizer 11 is oriented in the direction of 90 ° is detected.
For example, the driving device 13a rotates the analyzer 13 in the xy plane with the axis parallel to the z axis (light traveling direction) as the rotation axis, and sets the transmission axis direction ω of the analyzer 13 to an arbitrary angle ω ₀ . To do.
In this state, the driving device 11a rotates the polarizer 11 in the xy plane with the axis parallel to the z-axis (light traveling direction) as the rotation axis, and sets the transmission axis direction α of the polarizer 11 to 0 °. To do. The detection signal of the detection device 14 at this time is assumed to be transmitted light intensity I ^m (ω ₀ , 0 °).
Further, the polarizer 11 is rotated by the driving device 11a, and the transmission axis direction α of the polarizer 11 is set to 90 °. Then, the detection signal of the detection device 14 at this time is set to transmitted light intensity I ^m (ω ₀ , 90 °).
(Step 3)
Using the transmitted light intensity I ^m (ω ₀ , 0 °) and ^m (ω ₀ , 90 °) detected in step 2, the ratio r is obtained by [Equation 17].

[Formula 17]

(Step 4)
The transmitted light intensity I ^m (ω ₁ , α ₁ ) when the transmission axis direction of the polarizer 11 is directed to an arbitrary angle α ₁ and the transmission axis direction of the analyzer 13 is directed to an arbitrary angle ω _1. The transmitted light intensity I ^m (ω ₂ , α ₂ ) when the transmission axis direction of the polarizer 11 is directed to an arbitrary angle α2 and the transmission axis direction of the analyzer 13 is directed to an arbitrary angle ω ₂ is obtained. To detect. It should be noted that at least one of α ₁ and α ₂ and ω ₁ and ω ₂ may be different.
For example, by the drive unit 11a, to rotate the polarizer 11 as a rotation axis parallel to the z-axis (the traveling direction of light) to set the transmission axis alpha of the polarizer 11 at an arbitrary angle alpha _1.
In this state, by the drive unit 13a, to rotate the analyzer 13 as a rotation axis parallel to the z-axis (the traveling direction of light) to set the transmission axis direction omega of the analyzer 13 at any angle omega _1. The detection signal of the detection device 14 at this time is assumed to be transmitted light intensity I ^m (ω ₁ , α ₁ ).
Moreover, by the drive unit 11a rotates the polarizer 11, to set the transmission axis alpha of the polarizer 11 at an arbitrary angle alpha _2.
In this state, it is rotated by the drive unit 13a, to set the transmission axis direction omega of the analyzer 13 at an arbitrary angle omega _2. The detection signal of the detection device 14 at this time is defined as transmitted light intensity I ^m (ω ₂ , α ₂ ).

［式１８］
（ステップ６）
ＶＡセル１２の液晶層の厚さｄを求める場合には、ステップ５で求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率（Δｎ^ｅｆｆ＝ｎ_ｅ ^ｅｆｆ−ｎ_ｏ ^ｅｆｆ）（［式９］、[式１０]参照）で除算する。 (Step 5)
Using the transmitted light intensity I ^m (ω ₁ , α ₁ ) and I ^m (ω ₂ , α ₂ ) detected in step 4, the retardation R of the liquid crystal layer of the VA cell 12 is obtained by [Equation 18].

[Formula 18]
(Step 6)
When determining the thickness d of the liquid crystal layer of the VA cell 12, the retardation R of the liquid crystal layer of the VA cell 12 obtained in Step 5, the birefringence of the liquid crystal layer of the VA cell _{^{12 (Δn eff = n e eff}} - n _o ^eff ) (see [Expression 9] and [Expression 10]).

［式１９］ In the above, the transmitted light intensity for at least two or more combinations of ω and α (ω, α) in which at least one of ω and α is different is used, and the liquid crystal layer of the VA cell according to [Expression 15] and [Expression 16] The retardation of the liquid crystal layer can also be obtained by using a simpler formula than [Formula 15] and [Formula 16].
Below, the detection method which can detect the retardation of a liquid crystal layer using a simple formula is demonstrated.
First, the angle γ is obtained from [ratio r] obtained by [Expression 14] using [Expression 19].

[Formula 19]

［式２０］
これにより、偏光子１１の透過軸方向αを角度γに、検光子１３の透過軸方向ωを任意の角度ω_１に設定した時の透過光強度Ｉ(ω_１，γ)と、偏光子１１の透過軸方向αを角度γに、検光子１３の透過軸方向ωを任意の角度ω_２(≠ω_１)に設定した時の透過光強度Ｉ(ω_２，γ)との比は、[式２１]で表される。

［式２１］ Here, the transmitted light intensity I (ω, γ when the transmitted light direction of the polarizer 11 is directed to the direction of the angle γ determined by [Equation 19] and the transmission axis direction of the analyzer 13 is directed to the direction of the angle ω. ) Is expressed by [Expression 20].

[Formula 20]
Thus, the transmitted light intensity I (ω ₁ , γ) when the transmission axis direction α of the polarizer 11 is set to an angle γ and the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle ω ₁ , and the polarizer 11 When the transmission axis direction α is set to an angle γ and the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle ω ₂ (≠ ω ₁ ), the ratio to the transmitted light intensity I (ω ₂ , γ) is [Expression 21]

[Formula 21]

［式２２］
これにより、検光子１３の透過軸方向ωを角度γに、偏光子１１の透過軸方向αを任意の角度α_１に設定した時の透過光強度Ｉ(γ、α_１)と、検光子１３の透過軸方向ωを角度γに、偏光子１１の透過軸方向αを任意の角度α_２に(≠α_１)設定した時の透過光強度Ｉ(γ，α_２)との比は、[式２３]で表される。

［式２３］ Further, the transmitted light intensity I (γ, α) when the transmission axis direction of the analyzer 13 is directed to the direction of the angle γ determined by [Equation 19] and the transmission axis direction of the polarizer 11 is directed to the direction of the angle α. Is represented by [Equation 22].

[Formula 22]
Thus, the transmitted light intensity I (γ, α ₁ ) when the transmission axis direction ω of the analyzer 13 is set to an angle γ and the transmission axis direction α of the polarizer 11 is set to an arbitrary angle α ₁ , and the analyzer 13 When the transmission axis direction ω is set to an angle γ and the transmission axis direction α of the polarizer 11 is set to an arbitrary angle α ₂ (≠ α ₁ ), the ratio to the transmitted light intensity I (γ, α ₂ ) is It is expressed by Equation 23].

[Formula 23]

  In this way, at least two different transmission axis directions of the analyzer 13 with the transmission axis direction of the polarizer 11 or the transmission axis direction of the analyzer 13 oriented in the direction of the angle γ determined by [Equation 19]. By using the transmitted light intensity when set to at least two arbitrary angles or the transmitted light intensity when the transmission axis direction of the polarizer 11 is set to at least two or more different angles different from each other, The retardation R of the liquid crystal layer can be obtained using [Expression 20] to [Expression 23] which are simpler than [15] and [Expression 16].

In the first embodiment, the transmittances T _p and T _s of the VA cell 12 when light is incident on the VA cell 12 at an angle are taken into consideration, so that the transmittance of the VA cell 12 has polarization dependency. Even in this case (T _p ≠ T _s ), the retardation R and thickness d of the liquid crystal layer of the VA cell can be accurately detected. On the other hand, as is apparent from [Expression 16], [Expression 21], and [Expression 23], in the first embodiment, the values of these transmittances T _p and T _s are not required, and the VA cell 12 The retardation R and thickness d of the liquid crystal layer can be obtained (detected).
Therefore, the retardation R and the thickness d of the liquid crystal layer of the VA cell 12, which are parameters of the VA cell 12, can be detected easily and accurately.

[Second Embodiment]
[Equation 13] representing the transmitted light intensity when the transmission axis direction of the polarizer is α and the transmission axis direction of the analyzer is ω does not change at all even when α and ω are interchanged. That is, the polarizer described in the first embodiment can be replaced with an analyzer, and the analyzer can be replaced with a polarizer.
In the second embodiment, the transmission axis direction α of the polarizer 11 is set to an arbitrary angle, and the transmission axis direction ω of the analyzer 13 is parallel (ω = 0 °) and orthogonal (ω = 90) to the incident surface. The parameter of the VA cell 12 (detection target) is detected using the ratio r of the transmitted light intensity when set to (°).

［式２４］ The transmission axis direction α of the polarizer 11 is set to an arbitrary angle α ₀ (the transmission axis direction of the polarizer 11 is directed to the direction of angle α ₀ ), and the transmission axis direction ω of the analyzer 13 is set to 0 °. Let the transmitted light intensity (detection signal of the detection device 14) when the transmission axis direction of the analyzer 13 is directed to 0 ° be I (0 °, α ₀ ).
Further, the transmission axis direction α of the polarizer 11 is set to the arbitrary angle α _0, and the transmitted light intensity is set to I (90 °, α ₀ when the transmission axis direction ω of the analyzer 13 is set to 90 °. ).
Then, using the transmitted light intensity I (0 °, α ₀ ) and I (90 °, α ₀ ), the ratio r is obtained by [Equation 24].

[Formula 24]

［式２５］
ここで、偏光子１１の透過軸方向αと検光子１３の透過軸方向ωのすくなくとも一方が異なる、少なくとも２つ以上の組み合わせ（相異なる少なくとも２つ以上の組み合わせ）に対する透過光強度、例えば、任意の角度α_１と任意の角度ω_１の組み合わせ(ω_１，α_１)に対する透過光強度Ｉ(ω_１，α_１)と、任意の角度α_２と任意の角度ω_２の組み合わせ(ω_２，α_２)に対する透過光強度Ｉ(ω_２，α_２)との比は、[式２６]で表される。

［式２６］
なお、(ω，α)の相異なる組み合わせの選択方法としては、αのみが異なる組み合わせ、例えば、(ω_１，α_１)の組み合わせと(ω_１，α_２)の組み合わせを選択する方法や、ωのみが異なる組み合わせ、例えば、(ω_１，α_１)の組み合わせと(ω_２，α_１)の組み合わせを選択する方法を用いることができる。ω_１≠ω_２、α₁≠α_２でも構わない。 The transmitted light intensity I (ω, α) when the transmission axis direction of the polarizer 11 is set to an arbitrary angle α and the transmission axis direction of the analyzer 13 is set to an arbitrary angle ω is obtained by [Equation 24]. Is expressed by [Equation 25].

[Formula 25]
Here, the transmitted light intensity with respect to at least two or more combinations (at least two or more different combinations) in which at least one of the transmission axis direction α of the polarizer 11 and the transmission axis direction ω of the analyzer 13 is different, for example, arbitrary angle alpha ₁ and any combination of angles _{ω 1 (ω 1, α 1} ) the transmitted light intensity I (ω _{1, α 1)} with respect to a, any angle alpha ₂ and combinations of any angle omega ₂ (omega _2, transmitted light intensity I (omega ₂ for alpha _2), the ratio of the alpha ₂₎ is represented by [expression 26].

[Formula 26]
In addition, as a method for selecting different combinations of (ω, α), a method in which only α is different, for example, a method of selecting a combination of (ω ₁ , α ₁ ) and a combination of (ω ₁ , α ₂ ), A combination in which only ω is different, for example, a method of selecting a combination of (ω ₁ , α ₁ ) and a combination of (ω ₂ , α ₁ ) can be used. ω ₁ ≠ ω ₂ and α ₁ ≠ α ₂ may be used.

[Equation 26] does not include the transmittances T _p and T _s of the liquid crystal layer of the VA cell 12 as in [Equation 16]. For this reason, in [Equation 26], the only variable is the retardation R of the liquid crystal layer of the VA cell 12.
Therefore, I (ω ₁ , α ₁ ) and I (ω ₂ , α ₂ ) are detected by the detection device 14, and using the detected I (ω ₁ , α ₁ ) and I (ω ₂ , α ₂ ), From [Formula 26], the retardation R of the liquid crystal layer of the VA cell 12 can be obtained.
Further, by dividing the retardation R of the liquid crystal layer of the VA cell 12 obtained by [Equation 26] by the birefringence Δn ^eff of the liquid crystal layer of the VA cell 12, the thickness d of the liquid crystal layer of the VA cell 12 is obtained. be able to.
In the above, the specific value of r was obtained from [Equation 24]. However, it is not necessary to obtain a specific value of r by using an equation in which [Equation 24] is substituted for r in [Equation 25] or [Equation 26].
Further, the unknown variables in [Equation 25] are the retardation R and the coefficient I ₀ · T _p . Therefore, the transmitted light intensity I (ω, α when the transmission axis direction of the analyzer 13 is inclined at an arbitrary angle ω with respect to the incident surface and the polarization direction of the linearly polarized light is inclined at an arbitrary angle α with respect to the incident surface. ) Is detected for at least two or more combinations of ω and α (ω, α) in which at least one of ω or α is different, and the detected transmitted light intensity I (ω, α) is determined by [Equation 25]. By comparing with the calculated value, the retardation R of the liquid crystal layer can be obtained. For the comparison, for example, a least square method can be used.

［式２７］ The procedure of this embodiment will be described below.
(Step 1)
The VA cell 12 is installed in the parameter detection apparatus shown in FIG. 1 at an angle Θ with respect to the traveling direction (z-axis direction) of incident light.
(Step 2)
In a state where the transmission axis direction α of the polarizer 11 is set to an arbitrary angle α ₀ , the transmitted light intensity I ^m (0 °, α ₀ ) when the transmission axis direction ω of the analyzer 13 is set to 0 °, The transmitted light intensity I ^m (90 °, α ₀ ) when the transmission axis direction ω of the analyzer 13 is set to 90 ° is detected.
(Step 3)
Using the transmitted light intensity I ^m (0 °, α ₀ ) and I ^m (90 °, α ₀ ) detected in step 2, the ratio r is obtained by [Equation 27].

[Formula 27]

［式２８］
（ステップ６）
ＶＡセル１２の液晶層の厚さｄを求める場合には、ステップ５で求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率（Δｎ^ｅｆｆ＝ｎ_ｅ ^ｅｆｆ−ｎ_ｏ ^ｅｆｆ）で除算する。 (Step 4)
The transmitted light intensity I ^m (ω ₁ , α ₁ ) when the transmission axis direction α of the polarizer 11 is set to an arbitrary angle α ₁ and the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle ω ₁ , and polarization The transmitted light intensity I ^m (ω ₂ , α ₂ ) when the transmission axis direction ω of the probe 11 is set to an arbitrary angle α ₂ and the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle ω ₂ is detected. It should be noted that at least one of α ₁ and α ₂ and ω ₁ and ω ₂ may be different.
(Step 5)
Using the transmitted light intensity I ^m (ω ₁ , α ₁ ) and I ^m (ω ₂ , α ₂ ) detected in step 4, the retardation R of the liquid crystal layer of the VA cell 12 is obtained by [Equation 28].

[Formula 28]
(Step 6)
When determining the thickness d of the liquid crystal layer of the VA cell 12, the retardation R of the liquid crystal layer of the VA cell 12 obtained in Step 5, the birefringence of the liquid crystal layer of the VA cell _{^{12 (Δn eff = n e eff}} - n _o ^eff ).

［式２９］ In the above, the transmitted light intensity for at least two or more combinations of ω and α (ω, α) in which at least one of ω and α is different is used. Although R was calculated | required, the retardation R of a liquid-crystal layer can also be calculated | required using a formula simpler than [Formula 25] or [Formula 26].
Below, the detection method which detects the retardation of a liquid crystal layer using a simple formula is demonstrated.
First, the angle γ is obtained from the ratio r obtained in [Expression 24] using [Expression 29].

[Formula 29]

Here, the transmitted light intensity I (ω, γ when the transmitted light direction of the polarizer 11 is directed to the direction of the angle γ obtained by [Equation 29] and the transmission axis direction of the analyzer 13 is directed to the direction of the angle ω. ) Is expressed by [Expression 22].
Thus, the transmitted light intensity I (ω ₁ , γ) when the transmission axis direction of the polarizer 11 is set to an angle γ and the transmission axis direction of the analyzer 13 is set to an arbitrary angle ω ₁ , and the transmission of the polarizer 11 is obtained. The ratio with the transmitted light intensity I (ω ₂ , γ) when the axial direction is set to an angle γ and the transmission axis direction of the analyzer 13 is set to an arbitrary angle ω ₂ (≠ ω ₁ ) is expressed by [Equation 19]. expressed.

Further, the transmitted light intensity I (γ, α) when the transmission axis direction of the analyzer 13 is directed in the direction of the angle γ and the transmission axis direction of the polarizer 11 is directed in the direction of the angle α is expressed by [Equation 20]. expressed.
Thus, the transmitted light intensity I (γ, α ₁ ) when the transmission axis direction of the analyzer 13 is set to an angle γ and the transmission axis direction of the polarizer 11 is set to an arbitrary angle α ₁ , and the transmission of the analyzer 13 is obtained. The ratio to the transmitted light intensity I (γ, α ₂ ) when the axial direction is set to an angle γ and the transmission axis direction of the polarizer 11 is set to an arbitrary angle α ₂ (≠ α ₁ ) is expressed by [Equation 23]. expressed.

  In this way, at least two different transmission axis directions of the analyzer 13 with the transmission axis direction of the polarizer 11 or the transmission axis direction of the analyzer 13 oriented in the direction of the angle γ determined by [Equation 29]. By using the transmitted light intensity when set to at least two arbitrary angles or the transmitted light intensity when the transmission axis direction of the polarizer 11 is set to at least two or more different angles different from each other, The retardation R of the liquid crystal layer can be obtained using [Expression 20] to [Expression 23] which are simpler than [25] and [Expression 26].

Since the second embodiment considers the transmittances T _p and T _s of the VA cell 12 when light is incident obliquely on the VA cell 12 as in the first embodiment, the VA cell Even when the transmittance of 12 is polarization-dependent (T _p ≠ T _s ), the retardation R and thickness d of the liquid crystal layer of the VA cell can be accurately detected. In addition, the retardation R and thickness d of the liquid crystal layer of the VA cell 12 can be obtained without requiring the values of these transmittances T _p and T _s .
Therefore, the retardation R and thickness of the liquid crystal layer of the VA cell 12, which are parameters of the VA cell 12, can be detected easily and accurately.

[Third embodiment]
In the first embodiment or the second embodiment, the transmission axis direction ω of the analyzer 13 or the transmission axis direction α of the polarizer 11 is set to a specific direction in order to obtain the ratio r of the transmitted light intensity. However, the setting operation of the transmission axis direction α of the polarizer 11 and the transmission axis direction ω of the analyzer 13 can be facilitated.
In the third embodiment, when the transmission axis direction α of the polarizer 11 is set to an arbitrary angle, the transmission axis direction ω of the analyzer 13 is set to any three or more different angles. The retardation R of the liquid crystal layer of the VA cell 12 is directly detected using the transmitted light intensity.

［式３０］ [Expression 13] representing the transmitted light intensity when the transmission axis direction of the polarizer 1 is α and the transmission axis direction of the analyzer 13 is ω can be rewritten as [Expression 30].

[Formula 30]

［式３１］
そして、求めた変数Ａ、Ｂ、Ｃを用いて、［式３２］によりＶＡセル１２の液晶層のリタデーションＲを求めることができる。

［式３２］ In [Expression 30], the transmission axis direction α of the polarizer 11 and the transmission axis direction ω of the analyzer 13 are known, but I ₀ · T _p , I ₀ · T _s , R, A, B, and C are unknown. It is.
Here, the three variables A, B, and C are set so that the transmission axis direction ω of the analyzer 13 is set to at least three different angles while the transmission axis direction α of the polarizer 11 is set to an arbitrary angle. It can be obtained by comparing the transmitted light intensity when set with [Equation 31]. For example, when the transmission axis direction ω of the analyzer 13 is set at three different angles ω ₁ , ω ₂ , ω ₃ [ω _i (i = 1, 2, 3)], three transmitted light intensities I (ω ₁ , Α), I (ω ₂ , α), I (ω ₃ , α) [I (ω _i , α) (i = 1, 2, 3)] and [Equation 31] B and C can be obtained. As a comparison method, for example, a least square method can be used.

[Formula 31]
Then, using the obtained variables A, B, and C, the retardation R of the liquid crystal layer of the VA cell 12 can be obtained by [Expression 32].

[Formula 32]

When three variables A, B, and C are obtained using three transmitted light intensities when the transmission axis direction ω of the analyzer 13 is set to _three transmission axis directions ω _{1 to} ω 3, the three transmission axes When 45 ° and 135 ° in the direction ω ₁ ~ω ₃ is included at the same time, only three of the transmitted light intensity can not be obtained three variables a, B, and C. In this case, four or more transmitted light intensities when the transmission axis direction ω of the analyzer 13 is set to four or more angles are used.
When the transmission axis direction α of the polarizer 11 is set to 0 ° or 90 °, the variable C is always “0”. For this reason, it is necessary to set the transmission axis direction α of the polarizer 11 to an angle other than 0 ° and 90 °.

［式３３］
（ステップ４）
ステップ３で求めた変数Ａ^ｍ、Ｂ^ｍ、Ｃ^ｍを用いて、［式３４］によりＶＡセル１２の液晶層のリタデーションＲを求める。

［式３４］
（ステップ５）
ＶＡセル１２の液晶層の厚さｄを求める場合には、ステップ４で求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率（Δｎ^ｅｆｆ＝ｎ_ｅ ^ｅｆｆ−ｎ_ｏ ^ｅｆｆ）で除算する。 The procedure of this embodiment will be described below.
(Step 1)
The VA cell 12 is installed in the parameter detection apparatus shown in FIG. 1 at an angle Θ with respect to the traveling direction of incident light.
(Step 2)
With the transmission axis direction α of the polarizer 11 set to an arbitrary angle other than 0 ° and 90 °, the transmission axis direction ω of the analyzer 13 is set to three different angles ω ₁ , ω ₂ , ω ₃ (45 ° The transmitted light intensity I ^m (ω ₁ , α), I ^m (ω ₂ , α), and I ^m (ω ₃ , α) when it is set to (not including 135 ° at the same time) is detected.
(Step 3)
Transmitted light intensity I ^m (ω _i , α) (i = 1, 2, 3) detected in step 2 and transmitted light intensity I ^m (ω _i , α) (i = 1, 2, 3) are compared to determine the variables A ^m , B ^m , and C ^m .

[Formula 33]
(Step 4)
Using the variables A ^m , B ^m , and C ^m obtained in step 3, the retardation R of the liquid crystal layer of the VA cell 12 is obtained by [Equation 34].

[Formula 34]
(Step 5)
When determining the thickness d of the liquid crystal layer of the VA cell 12, the retardation R of the liquid crystal layer of the VA cell 12 obtained in Step 4, the birefringence of the liquid crystal layer of the VA cell _{^{12 (Δn eff = n e eff}} - n _o ^eff ).

Since the third embodiment considers the transmittances T _p and T _s of the VA cell 12 when light is incident obliquely on the VA cell 12 as in the first and second embodiments. Even when the transmittance of the VA cell 12 has polarization dependency (T _p ≠ T _s ), the retardation R and the thickness d of the liquid crystal layer of the VA cell can be accurately detected. In addition, the retardation R and thickness d of the liquid crystal layer of the VA cell 12 can be obtained without requiring the values of these transmittances T _p and T _s .
Therefore, the retardation R and thickness of the liquid crystal layer of the VA cell 12, which are parameters of the VA cell 12, can be detected easily and accurately.
Further, in the third embodiment, the transmission axis direction α of the polarizer 11 and the transmission axis direction ω of the analyzer 13 can be set to arbitrary angles as compared with the first embodiment.
For this reason, the transmission axis direction α of the polarizer 11 and the transmission axis direction ω of the analyzer 13 can be easily set, and the detection time of the transmitted light intensity can be shortened.

[Fourth Embodiment]
In the third embodiment, the transmitted light intensity I (ω _i , when the transmission axis direction ω of the analyzer 13 is set to three or more different angles ω _i (i = 1, 2, 3,...). α) (i = 1, 2, 3,...) was used to determine the variables A, B, and C. However, the processing for determining the variables A, B, and C by using an appropriate angle as the angle ω _i is performed. Can be omitted.
In the fourth embodiment, the transmitted light intensity I (() when the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle ω ₁ while the transmission axis direction α of the polarizer 11 is set to an arbitrary angle. ω ₁ , α), the transmitted light intensity I (ω ₂ , α) when the transmission axis direction ω of the analyzer is set to an angle ω ₂ (= ω ₁ + 90 °), and the transmission axis direction ω of the analyzer The retardation R of the liquid crystal layer of the VA cell 12 is directly detected using the transmitted light intensity I (ω ₃ , α) when the angle ω ₃ (= ω ₁ + 45 °) is set.

［式３５］ With the transmitted light intensity of the polarizer set to an arbitrary angle α, the transmitted light intensity ω of the analyzer 13 is set to an arbitrary angle ω ₁ , ω ₂ = ω ₁ + 90 °, ω ₃ = ω ₁ + 45 °, ω ₄ = Ω ₁ + 135 ° When the transmitted light intensity is I (ω ₁ , α), I (ω ₂ , α), I (ω ₃ , α), I (ω ₄ , α), 30] is expressed by [Expression 35].

[Formula 35]

［式３６］
また、［式３６］により求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率Δｎ^ｅｆｆで除算することによって、ＶＡセル１２の液晶層の厚さｄを求めることができる。 Accordingly, using the three transmitted light intensities I (ω ₁ , α), I (ω ₂ , α), I (ω ₃ , α), the retardation R of the liquid crystal layer of the VA cell 12 is directly calculated by [Equation 36]. Can be sought.

[Formula 36]
Further, by dividing the retardation R of the liquid crystal layer of the VA cell 12 obtained by [Expression 36] by the birefringence Δn ^eff of the liquid crystal layer of the VA cell 12, the thickness d of the liquid crystal layer of the VA cell 12 is obtained. be able to.

［式３７］
（ステップ４）
ＶＡセル１２の液晶層の厚さｄを求める場合には、ステップ３で求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率（Δｎ^ｅｆｆ＝ｎ_ｅ ^ｅｆｆ−ｎ_ｏ ^ｅｆｆ）で除算する。 The procedure of this embodiment will be described below.
(Step 1)
The VA cell 12 is installed in the parameter detection apparatus shown in FIG. 1 at an angle Θ with respect to the traveling direction of incident light.
(Step 2)
In a state where the transmission axis direction α of the polarizer 11 is set to an arbitrary angle other than 0 ° and 90 °, the transmitted light intensity I ^m (when the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle ω ₁ ( ω ₁ , α), transmitted light intensity I ^m (ω ₂ , α) when the transmission axis direction ω of the analyzer is set to an angle ω ₂ (= ω ₁ + 90 °), and the transmission axis direction ω of the analyzer Is detected at the angle ω ₃ (= ω ₁ + 45 °), and the transmitted light intensity I ^m (ω ₃ , α) is detected.
(Step 3)
Using the transmitted light intensity I ^m (ω ₁ , α), I ^m (ω ₂ , α), I ^m (ω ₃ , α) detected in step 2, the liquid crystal layer of the VA cell 12 is expressed by [Expression 37]. The retardation R is obtained.

[Formula 37]
(Step 4)
When determining the thickness d of the liquid crystal layer of the VA cell 12, the retardation R of the liquid crystal layer of the VA cell 12 obtained in Step 3, the birefringence of the liquid crystal layer of the VA cell _{^{12 (Δn eff = n e eff}} - n _o ^eff ).

[Fifth Embodiment]
In the fourth embodiment, the variables A, B, and C are set by setting the transmission axis direction ω of the analyzer 13 to an arbitrary angle ω ₁ , ω ₂ = ω ₁ + 90 °, and ω ₃ = ω ₁ + 45 °. Although the processing to obtain is omitted, the processing to obtain the variables A, B, and C can also be omitted by setting the transmission axis direction ω of the analyzer 13 to an angle other than this.
In the fifth embodiment, with the transmission axis direction of the polarizer 11 set to an arbitrary angle α, the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle ω ₁ , ω ₂ = ω ₁ + 90 °, ω The retardation R of the liquid crystal layer of the VA cell 12 is directly detected using the transmitted light intensity when set to ₄ = ω ₁ + 135 °.

［式３８］
また、［式３８］により求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率Δｎ^ｅｆｆで除算することによって、ＶＡセル１２の液晶層の厚さｄを求めることができる。 With the transmitted light intensity of the polarizer set to an arbitrary angle α, the transmitted light intensity ω of the analyzer 13 is set to an arbitrary angle ω ₁ , ω ₂ = ω ₁ + 90 °, ω ₃ = ω ₁ + 45 °, ω ₄ = Ω ₁ + 135 ° When the transmitted light intensity is I (ω ₁ , α), I (ω ₂ , α), I (ω ₃ , α), I (ω ₄ , α), 30] is expressed by [Expression 35].
Therefore, using the three transmitted light intensities I (ω ₁ , α), I (ω ₂ , α), I (ω ₄ , α), the retardation R of the liquid crystal layer of the VA cell 12 is directly calculated by [Equation 38]. Can be sought.

[Formula 38]
Further, the thickness R of the liquid crystal layer of the VA cell 12 is obtained by dividing the retardation R of the liquid crystal layer of the VA cell 12 obtained by [Equation 38] by the birefringence Δn ^eff of the liquid crystal layer of the VA cell 12. be able to.

［式３９］
（ステップ４）
ＶＡセル１２の液晶層の厚さｄを求める場合には、ステップ３で求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率（Δｎ^ｅｆｆ＝ｎ_ｅ ^ｅｆｆ−ｎ_ｏ ^ｅｆｆ）で除算する。 The procedure of this embodiment will be described below.
(Step 1)
The VA cell 12 is installed in the parameter detection apparatus shown in FIG. 1 at an angle Θ with respect to the traveling direction of incident light.
(Step 2)
The transmitted light intensity I ^m (ω when the transmission axis direction of the analyzer 13 is set to an arbitrary angle ω ₁ in a state where the transmission axis direction of the polarizer 11 is set to an arbitrary angle α other than 0 ° and 90 °. ₁ , α), the transmitted light intensity I ^m (ω ₂ , α) when the transmission axis direction of the analyzer is set to ω ₂ (= ω ₁ + 90 °), and the transmission axis direction of the analyzer to ω ₄ ( = (Transmitted light intensity I ^m (ω ₄ , α)) when set to (ω ₁ + 135 °).
(Step 3)
Using the transmitted light intensity I ^m (ω ₁ , α), I ^m (ω ₂ , α), I ^m (ω ₄ , α) detected in step 2, the liquid crystal layer of the VA cell 12 is expressed by [Equation 39]. The retardation R is obtained.

[Formula 39]
(Step 4)
When determining the thickness d of the liquid crystal layer of the VA cell 12, the retardation R of the liquid crystal layer of the VA cell 12 obtained in Step 3, the birefringence of the liquid crystal layer of the VA cell _{^{12 (Δn eff = n e eff}} - n _o ^eff ).

As in the first to third embodiments, the fourth and fifth embodiments take into account the transmittances T _p and T _s of the VA cell 12 when light is incident on the VA cell 12 obliquely. Therefore, even when the transmittance of the VA cell 12 has polarization dependency (T _p ≠ T _s ), the retardation R and the thickness d of the liquid crystal layer of the VA cell can be accurately detected. In addition, the retardation R and thickness d of the liquid crystal layer of the VA cell 12 can be obtained without requiring the values of these transmittances T _p and T _s .
Therefore, the retardation R and thickness of the liquid crystal layer of the VA cell 12, which are parameters of the VA cell 12, can be detected easily and accurately.
Further, the fourth and fifth embodiments do not require the variables A, B, and C as compared with the third embodiment, and therefore the processing of the processing device 15 is simplified.

[Sixth Embodiment]
[Equation 13] representing the transmitted light intensity when the transmission axis direction of the polarizer is α and the transmission axis direction of the analyzer is ω does not change at all even when α and ω are interchanged. That is, the polarizer described in the third embodiment can be replaced with an analyzer, and the analyzer can be replaced with a polarizer.
In the sixth embodiment, the transmitted light when the transmission axis direction α of the polarizer 11 is set to any three or more different angles while the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle. Using the intensity, the retardation R of the liquid crystal layer of the VA cell 12 is directly detected.

［式４０］
［式４０］では、偏光子１１の透過軸方向α、検光子１３の透過軸方向ωは既知であるが、Ｉ_０・Ｔ_ｐ、Ｉ_０・Ｔ_ｓ、Ｒ、Ａ、Ｂ、Ｃが未知である。
ここで、３つの変数Ａ、Ｂ、Ｃは、検光子１３の透過軸方向ωを任意の角度に設定した状態で、偏光子１１の透過軸方向αを、少なくとも３つ以上の異なる角度に設定した時の透過光強度と［式４１］を比較することによって求めることができる。例えば、偏光子１１の透過軸方向ωを３つの異なる角度α_１、α_２、α_３[α_ｉ(ｉ＝１，２，３）]に設定した時の３つの透過光強度Ｉ(ω，α_１)、Ｉ(ω，α_２)、Ｉ(ω，α_３)[Ｉ(ω，α_ｉ)（ｉ＝１，２，３）]と［式４１］を比較することによって変数Ａ、Ｂ、Ｃを求めることができる。比較方法としては、例えば、最小二乗法を用いることができる。

［式４１］
そして、求めた変数Ａ、Ｂ、Ｃを用いて、［式３２］によりＶＡセル１２の液晶層のリタデーションＲを求めることができる。 The transmission axis direction of the polarizer 11 is α, and the transmission axis direction of the analyzer 13 is ω. In the third embodiment, the transmission axis direction ω of the analyzer 13 is changed. However, if the transmission axis direction α of the polarizer 11 is changed, [Expression 19] representing the transmitted light intensity is expressed by [Expression 40]. Can be rewritten as

[Formula 40]
In [Equation 40], the transmission axis direction α of the polarizer 11 and the transmission axis direction ω of the analyzer 13 are known, but I ₀ · T _p , I ₀ · T _s , R, A, B, and C are unknown. It is.
Here, the three variables A, B, and C set the transmission axis direction α of the polarizer 11 to at least three or more different angles in a state where the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle. It can be obtained by comparing the transmitted light intensity at the time and [Equation 41]. For example, when the transmission axis direction ω of the polarizer 11 is set to three different angles α ₁ , α ₂ , α ₃ [α _i (i = 1, 2, 3)], three transmitted light intensities I (ω, α ₁ ), I (ω, α ₂ ), I (ω, α ₃ ) [I (ω, α _i ) (i = 1, 2, 3)] and [Equation 41] are compared to determine the variable A, B and C can be obtained. As a comparison method, for example, a least square method can be used.

[Formula 41]
Then, using the obtained variables A, B, and C, the retardation R of the liquid crystal layer of the VA cell 12 can be obtained by [Expression 32].

When the three variables A, B, and C are obtained using the three transmitted light intensities when the transmission axis direction α of the polarizer 11 is set to the _three transmission axis directions α _{1 to} α ₃ , the three transmission axes If 45 ° and 135 ° are simultaneously included in the directions α _{1 to} α ₃ , the three variables A, B, and C cannot be obtained with only the three transmitted light intensities. In this case, four or more transmitted light intensities when the transmission axis direction α of the polarizer 11 is set to four or more angles are used.
When the transmission axis direction ω of the analyzer 13 is set to 0 ° or 90 °, the variable C is always “0”. For this reason, the transmission axis direction ω of the analyzer 13 needs to be set to an angle other than 0 ° and 90 °.

［式４２］
（ステップ４）
ステップ３で求めた変数Ａ^ｍ、Ｂ^ｍ、Ｃ^ｍを用いて、［式３４］によりＶＡセル１２の液晶層のリタデーションＲを求める。
（ステップ５）
ＶＡセル１２の液晶層の厚さｄを求める場合には、ステップ４で求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率（Δｎ^ｅｆｆ＝ｎ_ｅ ^ｅｆｆ−ｎ_ｏ ^ｅｆｆ）で除算する。 The procedure of this embodiment will be described below.
(Step 1)
The VA cell 12 is installed in the parameter detection apparatus shown in FIG. 1 at an angle Θ with respect to the traveling direction of incident light.
(Step 2)
With the transmission axis direction ω of the analyzer 13 set to an arbitrary angle other than 0 ° and 90 °, the transmission axis direction α of the polarizer 11 is set to three different angles α ₁ , α ₂ , α ₃ (45 ° The transmitted light intensity I ^m (ω, α ₁ ), I ^m (ω, α ₂ ), and I ^m (ω, α ₃ ) are set.
(Step 3)
The transmitted light intensity I ^m (ω, α _i ) (i = 1, 2, 3) detected in step 2 and the transmitted light intensity I ^m (ω, α _i ) (i = 1, 2, 3) are compared to determine the variables A ^m , B ^m , and C ^m .

[Formula 42]
(Step 4)
Using the variables A ^m , B ^m , and C ^m obtained in step 3, the retardation R of the liquid crystal layer of the VA cell 12 is obtained by [Equation 34].
(Step 5)
When determining the thickness d of the liquid crystal layer of the VA cell 12, the retardation R of the liquid crystal layer of the VA cell 12 obtained in Step 4, the birefringence of the liquid crystal layer of the VA cell _{^{12 (Δn eff = n e eff}} - n _o ^eff ).

Since the sixth embodiment takes into account the transmittances T _p and T _s of the VA cell 12 when light is incident obliquely on the VA cell 12 as in the third embodiment, the VA cell Even when the transmittance of 12 has polarization dependency (T _p ≠ T _s ), the retardation R and thickness d of the liquid crystal layer of the VA cell can be accurately detected. In addition, the retardation R and thickness d of the liquid crystal layer of the VA cell 12 can be obtained without requiring the values of these transmittances T _p and T _s .
Therefore, the retardation R and the thickness d of the liquid crystal layer of the VA cell 12, which are parameters of the VA cell 12, can be detected easily and accurately.
Further, in the sixth embodiment, the transmission axis direction α of the polarizer 11 and the transmission axis direction ω of the analyzer 13 can be set to arbitrary angles as compared with the second embodiment.
For this reason, the transmission axis direction α of the polarizer 11 and the transmission axis direction ω of the analyzer 13 can be easily set, and the detection time of the transmitted light intensity can be shortened.

[Seventh Embodiment]
In the sixth embodiment, the transmitted light intensity I (ω, α when the transmission axis direction α of the polarizer 11 is set to three or more different angles α _i (i = 1, 2, 3,...). _{i) (i} = 1,2,3, variable a with · · ·), B, has been sought C, angle alpha _i as a variable a by using an appropriate angle, B, the process of obtaining the C Can be omitted.
In the seventh embodiment, in a state where the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle, the transmission axis direction α of the polarizer 11 is an angle α ₁ , an angle α ₂ = α ₁ +90 degrees, and α ₃ = The retardation R of the liquid crystal layer of the VA cell 12 is directly detected using the transmitted light intensity when set to α ₁ + 45 °.

［式４３］ With the transmitted light intensity ω of the analyzer 13 set to an arbitrary angle, the transmission axis direction α of the polarizer 11 is set to an arbitrary angle α ₁ , α ₂ = α ₁ +90 degrees, α ₃ = α ₁ + 45 °, α _If the transmitted light intensity when ₄ = α ₁ +135 degrees is I (ω, α ₁ ), I (ω, α ₂ ), I (ω, α ₃ ), I (ω, α ₄ ), [Expression 30] is expressed by [Expression 43].

[Formula 43]

［式４４］
また、［式４４］により求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率Δｎ^ｅｆｆで除算することによって、ＶＡセル１２の液晶層の厚さｄを求めることができる。 Accordingly, using the three transmitted light intensities I (ω, α ₁ ), I (ω, α ₂ ), I (ω, α ₃ ), the retardation R of the liquid crystal layer of the VA cell 12 is directly calculated by [Equation 44]. Can be sought.

[Formula 44]
Further, by dividing the retardation R of the liquid crystal layer of the VA cell 12 obtained by [Expression 44] by the birefringence Δn ^eff of the liquid crystal layer of the VA cell 12, the thickness d of the liquid crystal layer of the VA cell 12 is obtained. be able to.

［式４５］
（ステップ４）
ＶＡセル１２の液晶層の厚さｄを求める場合には、ステップ３で求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率（Δｎ^ｅｆｆ＝ｎ_ｅ ^ｅｆｆ−ｎ_ｏ ^ｅｆｆ）で除算する。 The procedure of this embodiment will be described below.
(Step 1)
The VA cell 12 is installed in the parameter detection apparatus shown in FIG. 1 at an angle Θ with respect to the traveling direction of incident light.
(Step 2)
In a state where the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle other than 0 ° and 90 °, the transmitted light intensity I ^m (when the transmission axis direction α of the polarizer 11 is set to an arbitrary angle α ₁ ( ω, α ₁ ), the transmitted light intensity I ^m (ω, α ₂ ) when the transmission axis direction α of the polarizer 11 is set to an angle α ₂ (= α ¹ + 90 °), and the transmission axis of the polarizer 11 The transmitted light intensity I ^m (ω, α ₃ ) when the direction α is set to an angle α ₃ (= α ₁ + 45 °) is detected.
(Step 3)
Using the transmitted light intensity I ^m (ω, α ₁ ), I ^m (ω, α ₂ ), and I ^m (ω, α ₃ ) detected in step 2, the liquid crystal layer of the VA cell 12 is expressed by [Equation 45]. The retardation R is obtained.

[Formula 45]
(Step 4)
When determining the thickness d of the liquid crystal layer of the VA cell 12, the retardation R of the liquid crystal layer of the VA cell 12 obtained in Step 3, the birefringence of the liquid crystal layer of the VA cell _{^{12 (Δn eff = n e eff}} - n _o ^eff ).

[Eighth Embodiment]
In the seventh embodiment, the variables A, B, and C are obtained by setting the transmission axis direction of the polarizer 11 to arbitrary angles α ₁ , α ₂ = α ₁ + 90 °, and α ₃ = α ₁ + 45 °. Although the processing is omitted, the processing for obtaining the variables A, B, and C can be omitted by setting the transmission axis direction α of the polarizer 11 to an angle other than this.
In the eighth embodiment, with the transmission axis direction ω of the analyzer 13 set to an arbitrary angle, the transmission axis direction of the polarizer 11 is set to an arbitrary angle α ₁ , α ₂ = α ₁ + 90 °, α _3. = The retardation R of the liquid crystal layer of the VA cell 12 is directly detected using the transmitted light intensity when set to = α ₁ + 135 °.

［式４６］
また、［式４６］により求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率Δｎ^ｅｆｆで除算することによって、ＶＡセル１２の液晶層の厚さｄを求めることができる。 With the transmitted light intensity ω of the analyzer 13 set to an arbitrary angle, the transmitted light intensity α of the polarizer 11 is set to an arbitrary angle α ₁ , α ₂ = α ₁ + 90 °, α3 = α1 + 45 °, α ₄ = α When the transmitted light intensity when set to ₁ + 135 ° is I (ω, α ₁ ), I (ω, α ₂ ), I (ω, α ₃ ), I (ω, α ₄ ), [Equation 30] Is represented by [Equation 43].
Therefore, using the three transmitted light intensities I (ω, α ₁ ), I (ω, α ₂ ), I (ω, α ₄ ), the retardation R of the liquid crystal layer of the VA cell 12 is directly calculated by [Equation 46]. Can be sought.

[Formula 46]
Further, the retardation R of the liquid crystal layer of the VA cell 12 obtained by [Equation 46] is divided by the birefringence Δn ^eff of the liquid crystal layer of the VA cell 12 to obtain the thickness d of the liquid crystal layer of the VA cell 12. be able to.

［式４７］
（ステップ４）
ＶＡセル１２の液晶層の厚さｄを求める場合には、ステップ３で求めたＶＡセル１２の液晶層のリタデーションＲを、ＶＡセル１２の液晶層の複屈折率（Δｎ^ｅｆｆ＝ｎ_ｅ ^ｅｆｆ−ｎ_ｏ ^ｅｆｆ）で除算する。 The procedure of this embodiment will be described below.
(Step 1)
The VA cell 12 is installed in the parameter detection apparatus shown in FIG. 1 at an angle Θ with respect to the traveling direction of incident light.
(Step 2)
In a state where the transmission axis direction ω of the analyzer 13 is set to an arbitrary angle other than 0 ° and 90 °, the transmitted light intensity I ^m (when the transmission axis direction α of the polarizer 11 is set to an arbitrary angle α ₁ ( ω, α ₁ ), the transmitted light intensity I ^m (ω, α ₂ ) when the transmission axis direction α of the polarizer 11 is set to an angle α ₂ (= α ₁ + 90 °), and the transmission axis of the polarizer 11 The transmitted light intensity I ^m (ω, α ₄ ) when the direction α is set to an angle α ₄ (= α1 + 135 °) is detected.
(Step 3)
Using the transmitted light intensity I ^m (ω, α ₁ ), I ^m (ω, α ₂ ), I ^m (ω, α ₄ ) detected in step 2, the liquid crystal layer of the VA cell 12 is expressed by [Equation 47]. The retardation R is obtained.

[Formula 47]
(Step 4)
When determining the thickness d of the liquid crystal layer of the VA cell 12, the retardation R of the liquid crystal layer of the VA cell 12 obtained in Step 3, the birefringence of the liquid crystal layer of the VA cell _{^{12 (Δn eff = n e eff}} - n _o ^eff ).

As in the first to sixth embodiments, the seventh and eighth embodiments take into account the transmittances T _p and T _s of the VA cell 12 when light is incident on the VA cell 12 obliquely. Therefore, even when the transmittance of the VA cell 12 has polarization dependency (T _p ≠ T _s ), the retardation R and the thickness d of the liquid crystal layer of the VA cell can be accurately detected. In addition, the retardation R and thickness d of the liquid crystal layer of the VA cell 12 can be obtained without requiring the values of these transmittances T _p and T _s .
Therefore, the retardation R and thickness of the liquid crystal layer of the VA cell 12, which are parameters of the VA cell 12, can be detected easily and accurately.
Further, in the seventh and eighth embodiments, it is not necessary to obtain the variables A, B, and C as compared with the sixth embodiment, so that the processing of the processing device 15 is simplified.

An experimental example will be described in which each transmitted light intensity of a detection target is detected using the present invention, and the retardation and thickness of the detection target are detected using each detected transmitted light intensity.
[Experimental Example 1]
As a detection target, a VA cell produced as follows was used.
As the transparent electrode, an approximately 3 cm square glass substrate having a circular transparent electrode with a diameter of about 1 cm on one side was used. A polyimide film for aligning liquid crystal molecules in parallel to the normal line of the glass substrate is provided on the transparent electrode side of the glass substrate. Then, the two glass substrates were bonded so that the transparent electrode sides face each other. Here, an ultraviolet curable adhesive mixed with resin beads having a diameter of 4.5 μm is applied to an inner portion of about 5 mm around the glass substrate, and the two glass substrates are cured by irradiating with ultraviolet rays. Since they are bonded, a gap corresponding to the diameter of the beads is formed between the glass substrates. A VA cell was fabricated by injecting a liquid crystal material into the gap between the glass substrates by utilizing capillary action.
The light emitting device 10 includes a halogen lamp and an interference filter that transmits monochromatic light having a wavelength λ of 546 nm.
Polarizer films were used for the polarizer 11 and the analyzer 13.
The detection device 14 used a CCD camera.
In the VA cell produced by the above-described method, the incident angle of incident light (angle between the normal of the substrate surface of the VA cell 12 and the incident direction of incident light) Θ is between the polarizer 11 and the analyzer 13. It installed so that it might become 30 degrees.

［式４８］
また、ＶＡセルの液晶材料の異常光屈折率ｎ_ｅ＝１．５６３３、常光屈折率ｎ_ｏ＝１．４７７６及び入射角Θ＝３０°を用いて、［式１０］によりＶＡセルの液晶層の複屈折率Δｎ^ｅｆｆを求めた。そして、［式４８］で求めたＶＡセルの液晶層のリタデーションＲ＝４０．４ｎｍを、ＶＡセルの液晶層の複屈折率Δｎ^ｅｆｆで除算することによって、ＶＡセルの液晶層の厚さｄ＝４．２３μｍが得られた。 In this state, the transmission axis direction α of the polarizer 11 is set to 45 ° (the transmission axis direction of the polarizer 11 is directed to the 45 ° direction), and the transmission axis direction ω of the analyzer 13 is set to 0 ° ( The transmitted light intensity (detection signal of the detection device 14) I ^m (0 °, 45 °) when the transmission axis direction of the analyzer 13 was directed to 0 ° was detected. Further, the transmitted light intensity ^Im (90 °, 45 °) when the transmission axis direction α of the polarizer 11 was set to 45 ° and the transmission axis direction ω of the analyzer 13 was set to 90 ° was detected.
Then, using the detected I ^m (0 °, 45 °) and I ^m (90 °, 45 °), the ratio r was obtained by [Equation 27], and r = 0.665 was obtained.
Next, the transmission axis direction α of the polarizer 11 is set to an angle [γ = 50.8 °] obtained by [Equation 29] using r, and the transmission axis direction ω of the analyzer 13 is set to 45 °. The transmitted light intensity I ^m (45 °, α) was detected. Further, the transmitted light intensity I ^m (135 °) when the transmission axis direction α of the polarizer 11 is set to the angle [γ = 50.8 °] and the transmission axis direction ω of the analyzer 13 is set to 135 °. , Α) was detected.
Then, using the detected I ^m (45 °, α) and I ^m (135 °, α), the retardation R of the liquid crystal layer of the VA cell was obtained by [Equation 48], and R = 40.4 nm was obtained. It was.

[Formula 48]
Further, using the extraordinary refractive index n _e = 1.5633, the ordinary refractive index n _o = 1.4776, and the incident angle Θ = 30 ° of the liquid crystal material of the VA cell, the liquid crystal layer of the VA cell is expressed by [Equation 10]. The birefringence index Δn ^eff was determined. Then, by dividing the retardation R = 40.4 nm of the liquid crystal layer of the VA cell obtained by [Equation 48] by the birefringence Δn ^eff of the liquid crystal layer of the VA cell, the thickness d = 4.23 μm was obtained.

［式４９］ [Experiment 2]
After the measurement of Experimental Example 1, the measurement of Experimental Example 2 was performed continuously without moving the VA cell.
When the same procedure as in Experimental Example 1 was performed until the angle γ was obtained, r = 0.670 was obtained.
When the transmission axis direction ω of the analyzer 13 is set to an angle [γ = 50.7 °] obtained by [Equation 29] using r, and the transmission axis direction α of the polarizer 11 is set to 45 °. The transmitted light intensity I ^m (ω, 45 °) was measured. The transmitted light intensity I ^m (ω, when the transmission axis direction ω of the analyzer 13 is set to the angle [γ = 50.7 °] and the transmission axis direction α of the polarizer 11 is set to 135 °. 135 °).
Then, using the detected I ^m (ω, 45 °) and I ^m (ω, 135 °), the retardation R of the liquid crystal layer of the VA cell was obtained by [Equation 49], and R = 40.3 nm was obtained. It was.
Further, when the thickness d of the liquid crystal layer of the VA cell was determined in the same procedure as in Experimental Example 1, d = 4.22 μm was obtained.

[Formula 49]

[Experiment 3]
The same VA cell as in experimental example 1 was used, and the measurement of experimental example 1 and 2 was performed without moving the VA cell, and then the measurement of experimental example 2 was performed.
The transmitted light intensity ^Im (45 °, 0 °) was detected when the transmission axis direction ω of the analyzer 13 was set to 45 ° and the transmission axis direction α of the polarizer 11 was set to 0 °. Further, the transmitted light intensity ^Im (45 °, 90 °) when the transmission axis direction ω of the analyzer 13 was set to 45 ° and the transmission axis direction α of the polarizer 11 was set to 90 ° was detected.
Using the detected I ^m (45 °, 0 °) and I ^m (45 °, 90 °), the ratio r was obtained by [Equation 17], and r = 0.665 was obtained.
Next, the transmission axis direction α of the polarizer 11 is set to an angle [γ = 50.8 °] obtained by [Equation 29] using r, and the transmission axis direction ω of the analyzer 13 is set to 45 °. The transmitted light intensity I ^m (45 °, α) was detected. Further, the transmitted light intensity I ^m (135 °) when the transmission axis direction α of the polarizer 11 is set to the angle [γ = 50.8 °] and the transmission axis direction ω of the analyzer 13 is set to 135 °. , Α) was detected.
Then, using the detected I ^m (45 °, α) and I ^m (135 °, α), the retardation R of the liquid crystal layer of the VA cell was obtained by [Equation 49], and R = 40.3 nm was obtained. It was.
Further, when the thickness d of the liquid crystal layer of the VA cell was determined in the same procedure as in Experimental Example 1, d = 4.22 μm was obtained.

[Example 4]
After the measurement of Experimental Example 3, the measurement of Experimental Example 4 was performed continuously without moving the VA cell.
When the same procedure as in Experimental Example 4 was performed until the angle γ was obtained, r = 0.660 was obtained.
Next, the transmission axis direction ω of the analyzer 13 was set to an angle [50.9 °] obtained from [Equation 29] using r, and the transmission axis direction α of the polarizer 11 was set to 45 °. The transmitted light intensity I ^m (ω, 45 °) at the time was detected. The transmitted light intensity I ^m (ω, 135 °) when the transmission axis direction ω of the analyzer 13 is set to the angle [50.9 °] and the transmission axis direction α of the polarizer 11 is set to 135 °. ) Was detected.
Then, using the detected I ^m (ω, 45 °) and I ^m (ω, 135 °), the retardation R of the liquid crystal layer of the VA cell was obtained by [Equation 49], and R = 40.5 nm was obtained. It was.
Further, when the thickness d of the liquid crystal layer of the VA cell was determined in the same procedure as in Experimental Example 1, d = 4.24 μm was obtained.

Experimental examples 1-4 measured the same place of the same VA cell continuously.
And in each Experimental example 1-4, the substantially equal value was obtained as retardation R and thickness d of a VA cell.

[式５０]
また、実験例１と同じ手順でＶＡセルの液晶層の厚さｄを求めたところ、ｄ＝４．５８μｍが得られた。 [Comparative Example 1]
In order to confirm the detection accuracy when the retardation and thickness of the detection target are detected using the present invention in consideration of the anisotropy of the transmittance of the liquid crystal layer, the detection target retardation and thickness are detected using the rotational analyzer method. Detected.
After performing the measurement of Experimental Example 4, the measurement of the Comparative Example was continuously performed without moving the VA cell.
The transmitted light intensity I ^m (45 °, 45 °) when the transmission axis direction α of the polarizer 11 was set to 45 ° and the transmission axis direction ω of the analyzer 13 was set to 45 ° was detected. Further, the transmitted light intensity ^Im (135 °, 45 °) when the transmission axis direction α of the polarizer 11 was set to 45 ° and the transmission axis direction ω of the analyzer 13 was set to 135 ° was detected.
Then, using the detected I ^m (45 °, 45 °) and I ^m (135 °, 45 °), the retardation R of the liquid crystal layer of the VA cell was obtained by [Equation 50], and R = 43. 8 nm was obtained.

[Formula 50]
Further, when the thickness d of the liquid crystal layer of the VA cell was determined in the same procedure as in Experimental Example 1, d = 4.58 μm was obtained.

  When the detection result of the comparative example and the detection result of Experimental Examples 1 to 4 in consideration of the anisotropy of the transmittance of the liquid crystal layer are compared, the detection result of the comparative example is measured despite measuring the same location of the same VA cell. Is different from the detection results of Experimental Examples 1 to 4.

[式５１]
次に、求めた変数Ａ^ｍ、Ｂ^ｍ、Ｃ^ｍを用いて、［式３４］により、ＶＡセルの液晶層のリタデーションＲを求めたところ、Ｒ＝４０．３ｎｍが得られた。
また、実験例１と同じ手順でＶＡセルの液晶層の厚さｄを求めたところ、ｄ＝４．２２μｍが得られた。 [Experimental Example 5]
After performing the measurement of the comparative example, the measurement of the experimental example 5 was continuously performed without moving the VA cell.
Transmitted light intensity I ^m (ω) when the transmission axis direction α of the polarizer 11 is set to 45 ° and the transmission axis direction ω of the analyzer 13 is set within a range from 0 ° to 90 ° at 10 ° intervals. _i , 45 °) (ω _i = 0 °, 10 °, 20 °... 80 °, 90 °).
Then, the detected _{^{I m (ω i, 45 °}} ) and the I _(ω i, 45 °) in the Expression 51], by comparing with the least squares method, the variable ^{A m,} B m, the ^{C m} As a result, A ^m = 24605, B ^m = 17227, and C ^m = 18412 (arbitrary unit) were obtained.

[Formula 51]
Next, the retardation R of the liquid crystal layer of the VA cell was obtained by [Formula 34] using the obtained variables A ^m , B ^m , and C ^m , and R = 40.3 nm was obtained.
Further, when the thickness d of the liquid crystal layer of the VA cell was determined in the same procedure as in Experimental Example 1, d = 4.22 μm was obtained.

[式５２]
また、実験例１と同じ手順でＶＡセルの液晶層の厚さｄを求めたところ、ｄ＝４．２
３μｍが得られた。 [Experimental Example 6]
After performing the measurement of Experimental Example 5, the measurement of Experimental Example 6 was continuously performed without moving the VA cell.
Transmitted light intensity I ^m (0 °, 45 °) when the transmission axis direction α of the polarizer 11 is set to 45 ° and the transmission axis direction ω of the analyzer 13 is set to 0 °, 45 °, 90 °, I ^m (45 °, 45 °) and I ^m (90 °, 45 °) were detected.
Then, using the detected I ^m (0 °, 45 °), I ^m (45 °, 45 °), and I ^m (90 °, 45 °), the retardation R of the liquid crystal layer of the VA cell is expressed by [Formula 52]. As a result, R = 40.4 nm was obtained.

[Formula 52]
Further, when the thickness d of the liquid crystal layer of the VA cell was determined by the same procedure as in Experimental Example 1, d = 4.2.
3 μm was obtained.

[式５３]
また、実験例１と同じ手順でＶＡセルの液晶層の厚さｄを求めたところ、ｄ＝４．２
３μｍが得られた。 [Experimental Example 7]
After the measurement of Experimental Example 6, the measurement of Experimental Example 7 was performed continuously without moving the VA cell.
Transmitted light intensity I ^m (0 °, 45 °) when the transmission axis direction α of the polarizer 11 is set to 45 ° and the transmission axis direction ω of the analyzer 13 is set to 0 °, 90 °, 135 °, I ^m (90 °, 45 °) and I ^m (135 °, 45 °) were detected.
Then, using the detected I ^m (0 °, 45 °), I ^m (90 °, 45 °), and I ^m (135 °, 45 °), the retardation R of the liquid crystal layer of the VA cell is expressed by [Formula 53]. As a result, R = 40.4 nm was obtained.

[Formula 53]
Further, when the thickness d of the liquid crystal layer of the VA cell was determined by the same procedure as in Experimental Example 1, d = 4.2.
3 μm was obtained.

[式５４]
次に、求めた変数Ａ^ｍ、Ｂ^ｍ、Ｃ^ｍを用いて、［式３４］により、ＶＡセルの液晶層のリタデーションＲを求めたところ、Ｒ＝４０．５ｎｍが得られた。
また、実験例１と同じ手順でＶＡセルの液晶層の厚さｄを求めたところ、ｄ＝４．２
４μｍが得られた。 [Experimental Example 8]
After performing the measurement of Experimental Example 7, the measurement of Experimental Example 8 was continuously performed without moving the VA cell.
The transmitted light intensity I ^m (45) when the transmission axis direction ω of the analyzer 13 is set to 45 ° and the transmission axis direction α of the polarizer 11 is set within a range from 0 ° to 90 ° at 10 ° intervals. °, α _i ) (α _i = 0 °, 10 °, 20 °... 80 °, 90 °).
Then, the detected _{^{I m (45 °, α i}} ) and I (45 °, α _i) of Expression 54], and by comparing with the least squares method, the variable ^{A m,} B m, the ^{C m} As a result, A ^m = 24857, B ^m = 17650, and C ^m = 18711 (arbitrary unit) were obtained.

[Formula 54]
Next, the retardation R of the liquid crystal layer of the VA cell was obtained by [Formula 34] using the obtained variables A ^m , B ^m , and C ^m , and R = 40.5 nm was obtained.
Further, when the thickness d of the liquid crystal layer of the VA cell was determined by the same procedure as in Experimental Example 1, d = 4.2.
4 μm was obtained.

[式５５]
また、実験例１と同じ手順でＶＡセルの液晶層の厚さｄを求めたところ、ｄ＝４．２
５μｍが得られた。 [Example 9]
After the measurement of Experimental Example 8, the measurement of Experimental Example 9 was performed continuously without moving the VA cell.
Transmitted light intensity I ^m (45 °, 0 °) when the transmission axis direction ω of the analyzer 13 is set to 45 ° and the transmission axis direction α of the polarizer 11 is set to 0 °, 45 °, 90 °, I ^m (45 °, 45 °) and I ^m (45 °, 90 °) were detected.
Then, using the detected transmitted light intensity I ^m (45 °, 0 °), I ^m (45 °, 45 °), and I ^m (45 °, 90 °), the liquid crystal of the VA cell is expressed by [Expression 55]. When the retardation R of the layer was determined, R = 40.6 nm was obtained.

[Formula 55]
Further, when the thickness d of the liquid crystal layer of the VA cell was determined by the same procedure as in Experimental Example 1, d = 4.2.
5 μm was obtained.

[式５６]
また、実験例１と同じ手順でＶＡセルの液晶層の厚さｄを求めたところ、ｄ＝４．２
５μｍが得られた。 [Example 10]
After performing the measurement of Experimental Example 9, the measurement of Experimental Example 10 was continuously performed without moving the VA cell.
Transmitted light intensity I ^m (45 °, 0 °) when the transmission axis direction ω of the analyzer 13 is set to 45 ° and the transmission axis direction α of the polarizer 11 is set to 0 °, 90 °, 135 °, I ^m (45 °, 90 °) and I ^m (45 °, 135 °) were detected.
Then, using the detected transmitted light intensity I ^m (45 °, 0 °), I ^m (45 °, 90 °), I ^m (45 °, 135 °), the liquid crystal of the VA cell according to [Formula 56]. When the retardation R of the layer was determined, R = 40.6 nm was obtained.

[Formula 56]
Further, when the thickness d of the liquid crystal layer of the VA cell was determined by the same procedure as in Experimental Example 1, d = 4.2.
5 μm was obtained.

[Experimental Example 5] to [Experimental Example 10] continuously measured the same location of the same VA cell as [Experimental Example 1] to [Experimental Example 4].
The retardation R and thickness d of the liquid crystal layer of the VA cell detected in [Experimental Example 5] to [Experimental Example 10] are substantially equal to the values detected in [Example 1] to [Example 4]. There was a value different from the comparative example.

The present invention is not limited to the configuration described in the embodiment, and various changes, additions, and deletions are possible.
For example, the retardation and thickness that are parameters of the VA cell are detected, but the present invention is not limited to the VA cell, and the retardation and thickness that are the detection target parameters that exhibit the same optical characteristics as the optical uniaxial medium are detected. It can be used as a parameter detection device.
Further, the parameter detection device is not limited to the configuration shown in FIG. 1 and can detect each of the transmitted light intensities described above, or retardation or the like as a parameter to be detected based on each transmitted light intensity. It is sufficient if the thickness can be detected.
In addition, the order of detecting each transmitted light intensity and the order of steps for detecting the retardation and thickness of the detection target can be appropriately changed.

It is a figure which shows one Embodiment of the parameter detection apparatus of the detection target of this invention. It is a figure explaining the coordinate system of the parameter detection apparatus shown in FIG.

Explanation of symbols

10 Light Emitting Device 11 Polarizer 12 VA Cell (Detection Object)
13 Analyzer 14 Detection Device 15 Processing Device

Claims (6)

  The major axis direction of the liquid crystal molecules is aligned in the direction perpendicular to the substrate surface, and linearly polarized light is incident at an angle inclined with respect to the normal of the substrate surface of the detection target having birefringence characteristics, and the detection target And a detection target parameter detection method capable of detecting the detection target parameter based on the transmitted light intensity of the light transmitted through the analyzer,
  A plane including a traveling direction of linearly polarized light incident on the substrate surface and a normal line of the substrate surface is an incident surface,
  Linearly polarized light whose polarization direction is inclined at an arbitrary angle α with respect to the incident surface is incident on the detection target,
  The transmission axis direction of the analyzer is an arbitrary angle ω with respect to the incident surface ₁ Transmitted light intensity I (ω when tilted ₁ , Α) and
  The direction of the transmission axis of the analyzer is an angle ω with respect to the incident surface ₂ (= Ω ₁ Transmitted light intensity I (ω when tilted at + 90 °) ₂ , Α) and
  The direction of the transmission axis of the analyzer is an angle ω with respect to the incident surface ₃ (= Ω ₁ Transmitted light intensity I (ω when tilted + 45 °) ₃ , Α)
  The detected transmitted light intensity I (ω ₁ , Α), I (ω ₂ , Α), I (ω ₃ , Α), the retardation R of the detection target is obtained by the following equation:

A method for detecting a parameter of a detection target, characterized by:   The major axis direction of the liquid crystal molecules is aligned in the direction perpendicular to the substrate surface, and linearly polarized light is incident at an angle inclined with respect to the normal of the substrate surface of the detection target having birefringence characteristics, and the detection target And a detection target parameter detection method capable of detecting the detection target parameter based on the transmitted light intensity of the light transmitted through the analyzer,
  A plane including a traveling direction of linearly polarized light incident on the substrate surface and a normal line of the substrate surface is an incident surface,
  Linearly polarized light whose polarization direction is inclined at an arbitrary angle α with respect to the incident surface is incident on the detection target,
  The transmission axis direction of the analyzer is an arbitrary angle ω with respect to the incident surface ₁ Transmitted light intensity when tilted I (ω ₁ , Α) and
  The direction of the transmission axis of the analyzer is an angle ω with respect to the incident surface ₂ (= Ω ₁ Transmitted light intensity I (ω when tilted at + 90 °) ₂ , Α) and
  The direction of the transmission axis of the analyzer is an angle ω with respect to the incident surface ₄ (= Ω ₁ + 135 °) Transmitted light intensity I (ω ₄ , Α)
  The detected transmitted light intensity I (ω ₁ , Α), I (ω ₂ , Α), I (ω ₄ , Α), the retardation R of the detection target is obtained by the following equation:

A method for detecting a parameter of a detection target, characterized by:   The major axis direction of the liquid crystal molecules is aligned in the direction perpendicular to the substrate surface, and linearly polarized light is incident at an angle inclined with respect to the normal of the substrate surface of the detection target having birefringence characteristics, and the detection target And a detection target parameter detection method capable of detecting the detection target parameter based on the transmitted light intensity of the light transmitted through the analyzer,
  A plane including a traveling direction of linearly polarized light incident on the substrate surface and a normal line of the substrate surface is an incident surface,
  The transmission axis direction of the analyzer is inclined at an arbitrary angle ω with respect to the incident surface,
  Polarization direction is arbitrary angle α ₁ Transmitted light intensity I (ω, α when inclined linearly polarized light is incident on the detection target ₁ )When,
  Polarization direction is angle α with respect to the incident surface ₂ (= Α ₁ Transmitted light intensity I (ω, α) when linearly polarized light inclined at + 90 ° is incident on the detection target. ₂ )When,
  Polarization direction is angle α with respect to the incident surface ₃ (= Α ₁ Transmitted light intensity I (ω, α) when linearly polarized light that is inclined at + 45 ° is incident on the detection target. ₃ )
  The detected transmitted light intensity I (ω, α ₁ ), I (ω, α ₂ ), I (ω, α ₃ ) To obtain the detection target retardation R by the following equation:

A method for detecting a parameter of a detection target, characterized by:   The major axis direction of the liquid crystal molecules is aligned in the direction perpendicular to the substrate surface, and linearly polarized light is incident at an angle inclined with respect to the normal of the substrate surface of the detection target having birefringence characteristics, and the detection target And a detection target parameter detection method capable of detecting the detection target parameter based on the transmitted light intensity of the light transmitted through the analyzer,
  A plane including a traveling direction of linearly polarized light incident on the substrate surface and a normal line of the substrate surface is an incident surface,
  The transmission axis direction of the analyzer is inclined at an arbitrary angle ω with respect to the incident surface,
  Polarization direction is arbitrary angle α ₁ Transmitted light intensity I (ω, α when inclined linearly polarized light is incident on the detection target ₁ )When,
  Polarization direction is angle α with respect to the incident surface ₂ (= Α ₁ Transmitted light intensity I (ω, α) when linearly polarized light inclined at + 90 ° is incident on the detection target. ₂ )When,
  Polarization direction is angle α with respect to the incident surface ₄ (= Α ₁ Intensity of transmitted light I (ω, α) when linearly polarized light inclined by + 135 ° is incident on the detection target ₄ )
  The detected transmitted light intensity I (ω, α ₁ ), I (ω, α ₂ ), I (ω, α ₄ ) To obtain the detection target retardation R by the following equation:

A method for detecting a parameter of a detection target, characterized by:   It is a parameter detection method of the detection object in any one of Claims 1-4,
  The thickness d of the detection target is obtained based on the detected retardation R of the detection target.
A method for detecting a parameter of a detection target, characterized by:   A long-axis direction of liquid crystal molecules is aligned in a direction perpendicular to the substrate surface, and is a detection target parameter detection device capable of detecting a detection target parameter having birefringence characteristics,
  A light source;
  A polarizer that transmits linearly polarized light in the transmission axis direction from the light emitted from the light source, and that is rotatable about an axis parallel to the traveling direction of the light emitted from the light source.
  A detection object arranged such that light transmitted through the polarizer is incident at an angle inclined with respect to the normal of the substrate surface;
  An analyzer that transmits linearly polarized light in a transmission axis direction from the light transmitted through the detection target, and the rotation axis is rotatable about an axis parallel to the traveling direction of the light transmitted through the detection target; ,
  A detection device that detects the intensity of light transmitted through the analyzer as transmitted light intensity;
  A processing device for inputting the transmitted light intensity detected by the detection device;
  The processing apparatus obtains at least one of the retardation R and the thickness d of the detection target using the method according to any one of claims 1 to 5.
A parameter detection device to be detected.

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