JP2015011259A - Photo-alignment irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photo-alignment irradiation device capable of accurately measuring the polarization characteristic of polarized light corresponding to an actually radiated light.SOLUTION: The photo-alignment irradiation device 2 includes a polarizer unit 10 for radiating polarized light to an alignment film on a work surface mounted on a stage 5. The polarizer unit 10 includes a plurality of unit polarizer units 12 arranged laterally. Each unit polarizer unit 12 includes a polarizer 16, and detecting means for detecting the polarization characteristic of light at the position corresponding to the stage 5 to which polarized lights having passed through the plurality of polarizers 16 are radiated in the overlap state.

Description

  The present invention relates to a photo-alignment irradiation apparatus provided with detection means for detecting a polarization direction.

Conventionally, a technique called photo-alignment is known in which alignment film or alignment layer (hereinafter referred to as “photo-alignment film”) is aligned by irradiating polarized light, and this photo-alignment is a liquid crystal display panel. The liquid crystal display element is widely applied to alignment of liquid crystal alignment films.
An irradiation device used for photo-alignment generally includes a light source and a polarizer, and obtains polarized light by passing light from the light source through the polarizer. In recent years, in order to photo-align a long strip-shaped photo-alignment film, a rod-shaped lamp having a length corresponding to the width of the photo-alignment film is used as a light source, and a plurality of polarizers are arranged in the longitudinal direction of the rod-shaped lamp to form a line shape. An irradiation apparatus that irradiates the polarized light is known, and the width direction of the band-shaped photo-alignment film is aligned with the direction in which the irradiation area of the polarized light of the irradiation apparatus extends, and the photo-alignment film is placed on the stage. A technique has also been proposed in which a belt-shaped photo-alignment film is uniformly photo-aligned by being conveyed in the length direction (see, for example, Patent Document 1).
There are two known factors for polarized light that affect the quality of photo-alignment: extinction ratio and variation in polarization axis distribution. These are adjusted with high accuracy as the irradiation device used for photo-alignment. It is important that Various techniques have been proposed for measuring polarization characteristics such as the extinction ratio and the polarization axis (see, for example, Patent Documents 2 to 4).

JP 2004-163881 A JP 2004-226209 A JP 2005-227019 A JP 2007-127567 A

In order to obtain a high-quality liquid crystal alignment film using photo-alignment, it is necessary to irradiate polarized light having a high extinction ratio and a polarization axis adjusted with an accuracy within 0.1 °. However, in order to adjust with accuracy within an error of 0.1 °, an error within 0.01 ° is required as a measurement accuracy. As a technique for measuring the polarization axis, a technique for measuring the polarization axis for each polarizer has been proposed. For this, a conventional polarization measurement technique can be used. However, in the above method, the angle at which the light is taken into the polarimeter is shallow, so that the optical alignment film on the stage at a position where the polarized light that has passed through the plurality of polarizers is superimposed and irradiated is actually irradiated. It does not mean that the polarization characteristics of the emitted light are measured.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a photo-alignment irradiation apparatus that can accurately measure the polarization characteristics of polarized light in accordance with light that is actually irradiated.

  In order to achieve the above-described object, the present invention provides a photo-alignment irradiation apparatus including a polarizer unit that irradiates polarized light onto an alignment film on a work surface placed on a stage. The polarizer units are aligned side by side. A plurality of unit polarizer units, each of which includes a polarizer, and detects polarization characteristics of light at the position corresponding to the stage where the polarized light that has passed through the plurality of polarizers is irradiated in an overlapping manner Means are provided.

  In the above-described configuration, the detection unit may include a detection unit provided so as to be movable in the arrangement direction of the unit polarizer units. Further, the detection unit may be able to move in the stage moving direction.

  In the above-described configuration, the detection unit includes a measurement polarizer, and detects the amount of light transmitted through the measurement polarizer while rotating the measurement polarizer; and the detection unit And a polarization measuring device that identifies a polarization characteristic of light at the stage-corresponding position based on the detection result, and the detector is disposed at the stage-corresponding position and has passed through the plurality of polarizers. Aperture that captures light that overlaps and enters the measurement polarizer, diffusion means that diffuses light that has passed through the measurement polarizer, and light that is diffused by the diffusion means is received to detect the amount of light And the polarization measuring device periodically changes the light quantity when the measuring polarizer rotates based on the light quantity at each rotation angle of the measuring polarizer. Change to obtain a change curve And curve calculation unit, and the polarization characteristic specifying means for specifying the polarization properties of the illumination light at the stage corresponding position based on the change curve may be provided.

  According to the present invention, since the detection means for detecting the polarization characteristics of the light at the position corresponding to the stage where the polarized light beams that have passed through the plurality of polarizers are superimposed and irradiated are provided, the alignment film on the workpiece surface arranged on the stage is actually provided. Since the polarization characteristics of the irradiated polarized light can be detected, the polarization characteristics in the actual irradiated light can be measured with sufficient accuracy without being excessive or insufficient.

It is a front view which shows typically the structure of the photo-alignment apparatus which concerns on this embodiment of this invention. It is a top view which shows the structure of a photo-alignment apparatus typically. It is a figure which shows the structure of a polarizer unit, (A) is a top view, (B) is a sectional side view. It is a schematic diagram which shows the structure of a detection part. It is explanatory drawing which shows the relationship between a polarizer unit and a detection part from a long-axis side. It is a graph which shows the relationship between an irradiation position and relative irradiation light quantity. It is explanatory drawing which shows the relationship between a polarizer unit and a detection part from a short-axis side. It is an external appearance perspective view which shows the structure of a detection part. It is sectional drawing of a detection part. It is a schematic diagram of a change curve of detection light. It is a schematic diagram which shows a polarization axis adjusting device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view showing the configuration of the photo-alignment apparatus according to this embodiment.
In the figure, a photo-alignment device (photo-alignment irradiation device) 2 is an irradiation device that performs photo-alignment by irradiating a photo-alignment film of a plate-like or band-like photo-alignment object (work) (FIG. 7) with polarized light. Yes, and equipped with a polarization measurement system 1 (detection means). This polarization measurement system 1 measures the polarization characteristics of the irradiation light of the photo-alignment device 2. As the polarization characteristics, the polarization direction of the polarized light and the extinction ratio are measured.

The photo-alignment apparatus 2 includes a stage transport base 3, an irradiator installation base 4, and a work stage (stage) 5 on which a photo-alignment target is placed.
The irradiator installation base 4 is a portal body that is horizontally mounted in the width direction of the stage transfer base 3 (a direction perpendicular to the linear movement direction X of a linear movement mechanism described later) at an upper position that is a predetermined distance away from the stage transfer base 3. Yes, both the pillars are fixed to the stage carrier 3. The irradiator installation stand 4 has a built-in irradiator 6, and the irradiator 6 irradiates polarized light directly below. In order to separate the vibration caused by the movement of the work stage 5 from the vibration caused by the cooling of the irradiator 6, the irradiator installation base 4 is not fixed to the stage transport base 3, but is separated from the stage transport base 3. It may be configured to be placed. The stage conveyance base 3 and the irradiator installation base 4 may have a vibration isolation structure.
The stage transport frame 3 is provided with a linear motion mechanism (not shown) that moves the work stage 5 along the linear motion direction X so as to pass directly below the irradiator 6 on the surface of the stage transport frame 3. ing. In the photo-alignment of the photo-alignment target object, the photo-alignment target object placed on the work stage 5 is transferred together with the work stage 5 by the linear motion mechanism and passes directly below the irradiator 6. The photo-alignment film is oriented by being exposed to polarized light.

The irradiator 6 includes a lamp 7 serving as a light source, a reflecting mirror 8, and a polarizer unit 10, and irradiates the condensed polarized light directly below.
The lamp 7 is a discharge lamp, and a straight tube (rod-shaped) ultraviolet lamp extending at least equal to or greater than the width of the photo-alignment object is used. The reflecting mirror 8 is a cylindrical concave reflecting mirror having an elliptical cross section and extending along the longitudinal direction of the lamp 7. The light from the lamp 7 is collected and irradiated toward the polarizer unit 10.
The polarizer unit 10 is disposed between the reflecting mirror 8 and the photo-alignment target, and polarizes light irradiated on the photo-alignment target. By irradiating this polarized light to the photo-alignment film of the photo-alignment object, the photo-alignment film is aligned.

FIG. 2 is a plan view schematically showing the configuration of the photo-alignment apparatus 2. 3A and 3B are diagrams illustrating the configuration of the polarizer unit 10, in which FIG. 3A is a plan view and FIG. 3B is a side sectional view. In FIG. 2, only the polarizer unit 10 is shown in the irradiator installation base 4 in order to facilitate understanding of the configuration of the polarizer unit 10.
As shown in the figure, the polarizer unit 10 includes a plurality of unit polarizer units (first polarizer) 12 and a frame 14 that aligns the unit polarizer units 12 side by side in a row. The frame 14 is a plate-like frame body in which the unit polarizer units 12 are connected and arranged. The unit polarizer unit 12 includes a wire grid polarizer (polarizer) 16 formed in a substantially rectangular plate shape.
In the present embodiment, each unit polarizer unit 12 supports the wire grid polarizer 16 so that the wire direction A is parallel to the linear motion direction X of the work stage 5, and a direction orthogonal to the wire direction A; The arrangement direction B of the wire grid polarizer 16 is made to coincide.

The wire grid polarizer 16 is a kind of linear polarizer. As described above, since the lamp 7 is rod-shaped, light of various angles is incident on the wire grid polarizer 16. However, the wire grid polarizer 16 linearly polarizes light that is incident obliquely. Through.
The wire grid polarizer 16 is supported by the unit polarizer unit 12 so that the direction of the polarization axis C1 can be finely adjusted by rotating in the plane with the normal direction as the rotation axis. With respect to all the unit polarizer units 12, the polarization axis C <b> 1 of the wire grid polarizer 16 is finely adjusted so as to align with a predetermined irradiation reference direction, so that the polarization axis C <b> 1 extends over the entire length of the polarizer unit 10 in the long axis direction. Is obtained with high accuracy, and high-quality optical alignment is possible. The wire grid polarizer 16 with the polarization axis C1 adjusted is fixedly arranged on the frame 14 by fixing the upper and lower ends of the unit polarizer unit 12 to the frame 14 with screws (fixing means) 19.

The wire grid polarizer 16 is formed of a material such as glass and is an optical element that is relatively fragile, and thus is held by the frame 14 via a cushioning material (not shown). The position of the wire grid polarizer 16 may be shifted due to the deterioration of the buffer material that holds the wire grid polarizer 16 or the vibration of the optical alignment apparatus 2, and as a result, the polarization direction of the polarized light is shifted.
Further, outgas may be generated from the alignment film during the processing (irradiation) of the photo-alignment target. When foreign matter such as outgas enters or adheres to the wire grid polarizer 16, the wire grid polarizer 16. Will change the polarization characteristics.

Therefore, in this embodiment, as shown in FIG. 2, a polarization measurement system 1 that measures the polarization direction of polarized light is provided.
The polarization measurement system 1 includes a polarization measurement device 20 and a measurement unit 30. The measurement unit 30 includes a detection unit 31 that detects polarized light, and the polarization measurement device 20 measures the polarization direction and extinction ratio of the polarized light based on the detection result of the polarized light by the detection unit 31.
The measurement unit 30 includes a linear guide 32 that guides the detection unit 31 along a straight line. At the time of polarized light measurement, the linear guide 32 is connected to the side surface 5A on the traveling direction side of the work stage 5 and is transferred directly below the polarizer unit 10, or the linear guide 32 is positioned directly below the polarizer unit 10. It is installed on the stage carrier 3. And the detection part 31 is moved along the linear guide 32 so that it may be located just under the wire grid polarizer 16 of fine adjustment object, or self-propelled, and the polarized light which permeate | transmitted the said wire grid polarizer 16 in the position is used. It detects with the detection part 31, and measures the polarization characteristic of irradiation light.

FIG. 4 is a schematic diagram illustrating the configuration of the detection unit 31.
The detection unit 31 includes a detection-side polarizer (second polarizer, measurement polarizer) 33 and a light receiving sensor 34.
The detection-side polarizer 33 is a plate-like (disk-like in the illustrated example) light-detecting linear polarizer having a polarization axis C2, and is also called an analyzer. The detection-side polarizer 33 receives the polarized light F that has been linearly polarized through the wire grid polarizer 16 and linearly polarizes the polarized light F. As the detection-side polarizer 33, any polarizer can be used as long as it is a linear polarizer. For example, a wire grid polarizer may be used.
The light receiving sensor 34 receives the detection light G linearly polarized by the polarization axis C2 of the detection side polarizer 33 and outputs a detection signal 35 indicating the light quantity I to the polarization measuring device 20 (FIG. 2).

  In the detection unit 31, the detection-side polarizer 33 is provided so as to be rotatable at least once with the normal direction S as a rotation axis. The rotation of the detection-side polarizer 33 is defined by the rotation angle θ from the reference position P0. In the present embodiment, the reference position P <b> 0 is set to a position where the direction of the polarization axis C <b> 2 matches the irradiation reference direction of the wire grid polarizer 16. That is, when the detection unit 31 is set on the linear guide 32 (FIG. 2) and the detection-side polarizer 33 is aligned with the reference position P0, the polarization axis C2 of the detection-side polarizer 33 is in the state of being directed to the irradiation reference direction. .

FIG. 5 is an explanatory diagram showing the relationship between the polarizer unit 10 and the detection unit 31 from the long axis side. FIG. 6 is a graph showing the relationship between the irradiation position and the relative irradiation light quantity. FIG. 7 is an explanatory diagram showing the relationship between the polarizer unit 10 and the detector 31 from the short axis side.
In the optical alignment device 2, the radiation light E of various angles emitted from the rod-shaped lamp 7 enters the wire grid polarizer 16, is linearly polarized by the wire grid polarizer 16, and is emitted as polarized light F. Is done. Such polarized light F includes various angular components.
Further, the wire grid polarizer 16 has a predetermined distance from the alignment film as shown in FIG. 5 for the purpose of improving the uniformity of the irradiated light and for preventing the outgas from the alignment film from adhering. Are placed apart.

Therefore, the polarized light F that has passed through the plurality of wire grid polarizers 16 is irradiated on the photo-alignment target object. The polarization characteristics of the polarized light F are not uniform due to the influence of the characteristic variation depending on the location of the passing polarizer and the influence of the incident angle, but the polarized light F having various polarization characteristics is irradiated to the photo-alignment object. Will be.
For example, in this embodiment, when the irradiation distribution in the longitudinal direction of the lamp 7 immediately below the irradiator 6 is separated for each wire grid polarizer 16 (n−3 to n + 1), a graph shown in FIG. 6 is obtained, and a certain irradiation position (0 mm) ) Is affected by three light beams on both sides. As shown in FIG. 6, for example, even immediately below the center of the wire grid polarizer 16, the amount of light that has passed through the wire grid polarizer 16 directly above is the total amount of light that has passed through the surrounding wire grid polarizer 16. It is about half of the irradiation light quantity.

  In addition, the structural member such as the polarizer 14 and the polarizer unit fixing base 9 that fixes the frame 14 is formed of a light shielding member, or is configured as a light shielding member by being covered with the light shielding member. However, reflection by structural members such as the frame 14 and the polarizer unit fixing base 9 cannot be completely prevented, and the reflected light H reflected by the structural member is also scattered light as shown in FIG. The light alignment target W on the work stage 5 is irradiated. The polarization characteristics of the polarized light F change depending on reflection. The reflected light H includes light reflected by the alignment film on the surface of the optical alignment target W and then reflected by the wire grid polarizer 16.

For this reason, for example, when measuring the polarization axis C1 for each wire grid polarizer 16 with the detection angle range of the detection light of the detection unit 31 narrowed, the polarized light F of the wire grid polarizer 16 other than the measurement target or The reflected light H cannot be measured. As a result, it cannot be said that the polarization characteristic of the irradiation light actually irradiated on the photo-alignment object is accurately measured.
Therefore, in the present embodiment, by using the detection unit 31 having the configuration described below, the polarization characteristics of the polarized light F (irradiated light) that is actually irradiated onto the photo-alignment target object by detecting a wide range of angular components. (Polarization direction, extinction ratio) can be measured.

FIG. 8 is an external perspective view showing the configuration of the detection unit 31, and FIG. 9 is a cross-sectional view of the detection unit 31.
As shown in these drawings, the detection unit 31 includes a rectangular plate-shaped base mount 70 on which a light receiving sensor unit 71, a detection-side polarizer 33, a rotary stage 72, and a detection light adjustment unit 73 are provided. (FIG. 9).
The light receiving sensor unit 71 includes a photomultiplier tube 74 as an example of the light receiving sensor 34, and a water-cooled base 75 that cools the photomultiplier tube 74 to keep the temperature constant and reduce noise due to the temperature characteristics of the photomultiplier tube 74. The detection signal 35 (FIG. 4) of the photomultiplier tube 74 is taken into the polarization measuring device 20 (FIG. 2).

  The base mount 70 engages with the linear guide 32 (FIG. 2) and is linearly guided by the linear guide 32. By setting a predetermined side of the base mount 70 in accordance with the major axis direction of the linear guide 32, the reference position P0 and the polarization axis C2 of the detection-side polarizer 33 are configured to be directed in the irradiation reference direction. . Note that the linear guide 32 is not necessarily used as long as a predetermined one side of the base mount 70 can be installed in the irradiation reference direction.

The detection-side polarizer 33 is disposed immediately above the detection surface 74A of the photomultiplier tube 74, and the incident side of the detection light G is covered with an aperture 76 in which an opening 76A having a predetermined diameter is formed. Although this aperture 76 restricts the incident light to the detection side polarizer 33, in this detection unit 31, the wire grid polarizer 16 also transmits obliquely incident light to generate polarized light F. In addition, the aperture 76A is formed so as to pass the polarized light F having an incident angle Y in the range of 0 ° to 70 ° so as to capture the polarized light F due to these obliquely incident components.
The range of the incident angle Y is a component of the polarized light F emitted obliquely from the wire grid polarizer 16 based on the shapes and arrangement relationships of the detector 31, the wire grid polarizer 16, and the lamp 7. Is determined as the angle at which is taken.

The detection light adjustment unit 73 is a cylindrical member disposed between the detection-side polarizer 33 and the detection surface 74A of the photomultiplier tube 74. The detection light adjustment unit 73 includes a cylindrical body 77 and is taken in through the aperture 76 and detected. The detection light G that has passed through the polarizer 33 is taken in from the upper surface of the cylindrical body 77, mixed inside, and guided to the photomultiplier tube 74 from the lower surface.
Specifically, the upper surface of the cylindrical body 77 of the detection light adjusting unit 73 is provided with an aperture 78 in which an opening 78A through which detection light G in a range up to an incident angle Y taken in by the aperture 76 passes is formed. Yes.

  In the cylindrical body 77, a diffusion unit 79 for diffusing transmitted light does not leave a gap immediately below the aperture 78 in order to secure a wide light incident angle and to cancel the polarization state of the incoming light and to make it non-polarized. Is provided. The diffusing unit 79 includes two diffusing plates 79A and 79B arranged facing each other at a predetermined interval, and mixes and outputs the detection light G having various incident angles Y. For the diffusion plates 79A and 79B, for example, frost type synthetic quartz plates are used.

A plate member 80 formed with a pinhole 80A for limiting the amount of light incident on the photomultiplier tube 74 is provided on the lower surface of the cylindrical body 77, and light passing through the pinhole 80A is detected by the photomultiplier tube 74. It is incident on 74A.
In addition, a wavelength limiting filter 81 that cuts light having a wavelength other than the photo-alignment wavelength is provided between the pinhole 80A and the detection surface 74A of the photomultiplier tube 74. The cut light is guided to the photomultiplier tube 74.

  As described above, the detection unit 31 is configured to take the polarized light F up to a relatively large incident angle Y, diffuse the inside thereof, and detect the amount of light with the photomultiplier tube 74. Therefore, the light emitted from the rod-shaped lamp 7 is emitted. Like the polarized light F obtained by passing E through the wire grid polarizer 16, the polarized light F includes various angle components and also includes polarized light components of a plurality of wire grid polarizers 16. The polarization characteristics can be measured by detecting the range of the angle component.

Next, the polarization measuring device 20 will be described in detail.
The polarization measuring device 20 measures the polarization direction and extinction ratio of the polarized light F based on a periodic change in the amount of the detected light G when the detection-side polarizer 33 rotates once. Specifically, as shown in FIG. 2, the polarization measuring device 20 includes a rotation drive control unit 21, an input unit 22, a change curve calculation unit 23, a polarization characteristic specifying unit 24, and a polarization characteristic output unit 25. It has. Note that the polarization measuring device 20 can also be implemented by causing a personal computer to execute a computer-readable program that implements each unit illustrated in FIG. 2, for example.
The rotation drive control unit 21 controls the rotation of the detection side polarizer 33 (FIG. 4) of the detection unit 31. Specifically, the detection unit 31 includes a rotary actuator that rotates the detection-side polarizer 33, and the rotation drive control unit 21 controls the rotary actuator to rotate the detection-side polarizer 33, so that its polarization axis is adjusted. C2 is adjusted to the direction of a predetermined rotation angle θ. The rotation angle θ at this time is output to the change curve calculation unit 23.
The input unit 22 is means for receiving an input of a detection value of the light amount I of the detection light G, and the detection signal 35 of the detection unit 31 is input to the input unit 22. The input unit 22 acquires the detection value of the light amount I of the detection light G from the detection signal 35 and outputs it to the change curve calculation unit 23.

The change curve calculation unit 23 calculates a change curve Q indicating a periodic change in the light amount I of the detection light G when the detection-side polarizer 33 is rotated once based on the detection value of the light amount I of the detection light G. . More specifically, as shown in FIG. 5, the detection light G is light obtained by sequentially passing the radiation light E of the lamp 7 through the wire grid polarizer 16, which is a linear polarizer, and the detection-side polarizer 33. Thus, the polarized light of the plurality of wire grid polarizers 16 is overlapped.
Therefore, the change curve Q of the light amount I of the detection light G accompanying the rotation of the detection side polarizer 33 is ideally the polarization axis C2 of the detection side polarizer 33 is polarized light of the polarized light F as shown in FIG. When it is parallel to the direction (in this embodiment, the rotation angle θ = 0 °, 180 ° (maximum point)), the maximum light amount Imax (maximum value) is obtained, and the polarization axis C2 is orthogonal to the polarization direction of the polarized light F (In this embodiment, the rotation angle θ = 90 °, 270 ° (minimum point)) and the following formula (1) where one cycle is π [rad] (= 180 °) such that the minimum light amount Imin (minimum value) is obtained. (The so-called Low of Malus).

Change curve Q = α × cos (β × (θ−γ)) + ε (1)
Where α is the amplitude, β is the period, γ is the phase shift (phase difference in the polarization direction of the polarized light F with respect to the reference position P0), and ε is the bias component.

The change curve calculation unit 23 obtains the cosine waveform shown in the equation (1) based on the detected value of the light amount I of the detection light G by a curve fitting (also referred to as curve regression) method, and obtains the cosine waveform. Output to.
When the polarization direction of the polarized light F is deviated from the direction of the reference position P0, the deviation appears as a phase deviation γ (> 0) in the change curve Q as shown by a virtual line in FIG.

The polarization characteristic specifying unit 24 specifies the polarization direction and extinction ratio of the polarized light F based on the change curve Q obtained by the change curve calculating unit 23, and outputs it to the polarization characteristic output unit 25.
Specifically, as shown in FIG. 10, the polarization characteristic specifying unit 24 specifies γ, which is the rotation angle θ (maximum point) at which the maximum light amount Imax of the detection light G is obtained, in the change curve Q. Then, the polarization direction of the polarized light is specified, and the extinction ratio is specified based on the ratio of the maximum light amount Imax and the minimum light amount Imin (= maximum light amount Imax / minimum light amount Imin) of the change curve Q. The maximum light amount Imax in the change curve Q is obtained by substituting the rotation angle θ = γ (maximum point) into the change curve Q, and the minimum light amount Imin is assigned the rotation angle θ = 90 ° + γ (minimum point). Is required. Since the detection light G includes the polarized light and reflected light of the plurality of wire grid polarizers 16, the polarization direction and extinction ratio of the polarized light are distributed, but the polarization direction and extinction ratio of the polarized light are distributed. It will be obtained based on the peak value.

  The polarization characteristic output unit 25 outputs the polarization characteristics (polarization direction and extinction ratio) specified by the polarization characteristic specification unit 24. This output mode is arbitrary as long as the user can use the polarization characteristics, and examples thereof include display, output to another electronic device, and recording on a recording medium.

Next, with reference to FIG. 11, measurement of polarized light of the optical alignment apparatus 2 will be described.
FIG. 11 is a schematic diagram showing the polarization axis adjusting device D. As shown in FIG.
The polarization axis adjustment device D includes a polarization measurement system 1A and a spot light source 7A, and is a device that adjusts the direction of the polarization axis C1 of the wire grid polarizer 16. The polarization measurement system 1A has the same configuration as the polarization measurement system 1 except that the opening (not shown) of the detection unit 31A is formed narrower than the opening 76A of the detection unit 31 of the polarization measurement system 1. In FIG. 11, the same parts as those of the photo-alignment apparatus 2 are denoted by the same reference numerals, and description thereof is omitted.

First, the operator arranges the polarizer unit 10 in the polarization axis adjusting device D on another ground. Next, the operator arranges the detection unit 31 </ b> A of the polarization axis adjusting device D immediately below the wire grid polarizer 16 to be measured, and arranges the spot light source 7 </ b> A directly above the wire grid polarizer 16 to be measured. Then, the operator detects the polarized light F emitted from the wire grid polarizer 16 using the polarization measurement system 1A, and measures the polarization axis C1 and the extinction ratio of the wire grid polarizer 16. The operator finely adjusts the rotation of the wire grid polarizer 16 as necessary based on the measurement result of the polarization axis C1, thereby setting the direction of the polarization axis C1 to a predetermined direction (in this embodiment, the irradiation reference direction). Match.
The operator performs measurement of polarized light F in the same manner for all the wire grid polarizers 16 included in the polarizer unit 10, and based on the measurement result, performs the work of adjusting the direction of the polarization axis C1 to the irradiation reference direction. The direction of the polarization axis C1 of the wire grid polarizer 16 is aligned with the irradiation reference direction.

Next, the operator installs the adjusted polarizer unit 10 in the optical alignment apparatus 2 and instructs the polarization measurement system 1 to start measurement of polarization characteristics (polarization direction, extinction ratio). The polarization characteristics are measured at a plurality of measurement points in the arrangement direction B of the wire grid polarizer 16, and the measurement points are set by an operator and stored in the polarization measurement system 1.
The polarization measurement system 1 arranges the detection unit 31 by guiding it with a linear guide 32 at a set predetermined measurement point, detects the polarized light F emitted from the wire grid polarizer 16, and detects the polarization direction and the quenching. Measure the ratio. When the polarization measurement system 1 measures the polarized light F at all measurement points, the polarization measurement system 1 outputs the result and the pass / fail judgment to the polarization characteristic output unit 25. The pass / fail judgment value is also set by the operator and stored in the polarization measurement system 1.
As described above, according to the photo-alignment apparatus 2, the polarized light actually irradiated onto the photo-alignment object is measured, so that the polarization direction of the polarized light is specified with high accuracy. In the photo-alignment apparatus 2, the polarization characteristics irradiated on the photo-alignment target object indicate the performance of the photo-alignment apparatus 2, and it is a factor that determines the quality of the alignment film that is aligned by polarized light. It is very important to understand its characteristics.

  The operator finishes the measurement when the polarization characteristics satisfy the standard at all the measurement points, and when even one of the polarization characteristics does not satisfy the standard, the polarization of the wire grid polarizer 16 in the polarization axis adjustment device D The direction of the axis C1 is adjusted, or the polarizer unit 10 is maintained. In addition, since the wire grid polarizer 16 is fixed to the frame 14 by the screw 19 after adjustment, the direction of the polarization axis C1 of the wire grid polarizer 16 is set in the installation from the polarization axis adjustment device D to the optical alignment device 2 or the like. It will not change. Further, in the optical alignment apparatus 2, the polarization characteristics are not always measured by the polarization measurement system 1, but the polarization characteristics may be measured after a predetermined period, for example, one month after the polarization characteristics change due to aging or outgassing. .

  As described above, according to the present embodiment, the polarization measurement that detects the polarization direction of the light at the position corresponding to the work stage 5 where the polarized light beams that have passed through the plurality of wire grid polarizers 16 aligned side by side overlap and are irradiated. The system 1 is provided. With this configuration, it is possible to detect the polarization characteristics of the polarized light that is actually irradiated onto the alignment film on the surface of the photo-alignment target object placed on the work stage 5, so that the polarization direction can be accurately measured.

  Further, according to the present embodiment, the polarization measuring system 1 is configured to include the detection unit 31 provided so as to be movable in the arrangement direction of the unit polarizer units 12. With this configuration, it is possible to measure the polarization characteristics at each measurement point in the arrangement direction of the unit polarizer units 12, so by reducing the interval between the measurement points, the polarization characteristics for each place irradiated to the photo-alignment object can be detailed. You can get it.

Further, according to the present embodiment, the detection unit 31 takes in the polarized light F including the oblique incident component and enters the detection side polarizer 33, and the diffusion unit 79 that diffuses the light transmitted through the detection side polarizer 33. And a photomultiplier tube 74 as a light receiving sensor that receives the light diffused by the diffusing unit 79 and detects the light quantity I.
Thereby, even in the case of the polarized light F including various angular components, such as the polarized light F obtained by passing the radiated light E of the rod-shaped lamp 7 through the wire grid polarizer 16, a wide range of angular components is obtained. Can be detected to measure the polarization characteristics.

  The above-described embodiment is merely an example of the present invention, and can be arbitrarily modified and applied without departing from the spirit of the present invention.

For example, in the above-described embodiment, the lamp 7 that is a discharge lamp is exemplified as the light source of the polarized light, but the light source is not limited to this and is arbitrary. That is, the present invention can be used for measuring linearly polarized polarized light obtained by transmitting light from an arbitrary light source through a polarizer. The light source is not necessarily a linear light source.
Further, for example, in the above-described embodiment, the wire grid polarizer 16 is illustrated as an example of the polarizer that obtains the polarized light to be measured, but the polarizer is not limited to this. That is, the polarizer is arbitrary as long as it is a polarizer capable of obtaining linearly polarized polarized light.

Further, for example, in the above-described embodiment, the configuration in which the polarization measuring device 20 measures both the polarization direction and the extinction ratio of the polarized light is exemplified, but only one of them may be measured. In addition to the polarization direction and / or extinction ratio of the polarized light, the polarization measuring device 20 may measure other characteristics such as light intensity.
Further, for example, in the above-described embodiment, the polarization measurement device 20 acquires the light amount of the detection light G by inputting the detection signal 35 of the detection unit 31 to the polarization measurement device 20, but the configuration is not limited thereto. That is, the recording data in which the correspondence between the rotation angle θ and the amount of the detection light G is recorded may be acquired from, for example, another electronic device or a recording medium (for example, a semiconductor memory).

  In the above-described embodiment, the detection unit 31 is provided so as to be movable in the arrangement direction B of the unit polarizer units 12, but is not limited to this. For example, the detection unit 31 includes: It may be possible to move in the stage moving direction.

2 Photo-alignment device (photo-alignment irradiation device)
1 Polarization measurement system (detection means)
5 Work stage (stage)
10 Polarizer Unit 12 Unit Polarizer Unit 16 Wire Grid Polarizer (Polarizer)
W Optical alignment object (work)

Claims (3)

In a photo-alignment irradiation apparatus equipped with a polarizer unit that irradiates polarized light to the alignment film on the work surface placed on the stage,
The polarizer unit includes a plurality of unit polarizer units arranged side by side, and each of the unit polarizer units includes a polarizer, and the polarized light passing through the plurality of polarizers is overlapped and irradiated at a position corresponding to the stage. A photo-alignment irradiation apparatus comprising a detecting means for detecting the polarization characteristics of the light.   The photo-alignment irradiation apparatus according to claim 1, wherein the detection unit includes a detection unit provided so as to be movable in an arrangement direction of the unit polarizer units. The detection means includes
A detection unit having a measurement polarizer and detecting the amount of light transmitted through the measurement polarizer while rotating the measurement polarizer;
A polarization measuring device that identifies polarization characteristics of light at the position corresponding to the stage based on the detection result of the detection unit, and
The detector is
An aperture that is disposed at a position corresponding to the stage and that captures light in which the polarized light that has passed through the plurality of polarizers overlaps and enters the measurement polarizer;
Diffusing means for diffusing the light transmitted through the measurement polarizer;
A light receiving sensor that receives the light diffused by the diffusing means and detects the amount of light, and
The polarization measuring device includes:
Based on the amount of light at each rotation angle of the measurement polarizer, a change curve calculation means for obtaining a change curve indicating a periodic change in the amount of light when the measurement polarizer rotates;
The photo-alignment irradiation apparatus according to claim 1, further comprising: a polarization characteristic specifying unit that specifies a polarization characteristic of the irradiation light at the position corresponding to the stage based on the change curve.

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