JP4706255B2 - Polarized light irradiation device - Google Patents

Description

  The present invention relates to a polarized light irradiation apparatus that irradiates polarized light to an alignment film of a liquid crystal element, an alignment layer of a viewing angle compensation film using an ultraviolet curable liquid crystal, and the like, thereby generating alignment characteristics.

In recent years, a technique called photo-alignment has been adopted in which alignment is performed by irradiating polarized light of a predetermined wavelength with respect to alignment processing of alignment films of liquid crystal display elements such as liquid crystal panels and alignment layers of viewing angle compensation films. It has come to be. Hereinafter, films and layers in which alignment characteristics are generated by light, such as alignment films that align with light and films provided with alignment layers, are collectively referred to as photo-alignment films.
The photo-alignment film has been enlarged with the enlargement of the liquid crystal panel in which it is used. For example, the viewing angle compensation film is a long strip-like work, and is cut to a desired length after the orientation treatment. In recent products, the width has been increased to 1500 mm.
For example, Patent Document 1 and Patent Document 2 have been proposed as devices for photoalignment for a wide band-shaped photoalignment film as described above.
In Patent Documents 1 and 2, light from a rod-shaped lamp that is a linear light source having a length corresponding to the width of the photo-alignment film is polarized by a polarizing element and orthogonal to the longitudinal direction of the rod-shaped lamp. It has been proposed to irradiate an alignment film that is conveyed in the direction of movement.
A rod-shaped lamp having a relatively long length is conventionally manufactured, and a rod-shaped lamp having a length of, for example, 1500 mm described above corresponding to the width direction of the photo-alignment film can be manufactured.
However, since the light emitted from the rod-shaped lamp is diffused light, it is necessary to select a polarizing element that efficiently polarizes the diffused light. In the above publication, a polarizing element called a wire grid polarizer is used as such a polarizing element. Has been.

Details of the wire grid polarization element are disclosed in, for example, Patent Document 3 and Patent Document 4. As shown in FIG. 11, the schematic structure is that a plurality of linear electric conductors 10a whose length is much longer than the width (for example, metal wires such as chromium and aluminum; hereinafter referred to as grids) are on the same plane ( For example, it is arranged in parallel on the substrate 10b such as quartz glass. When the polarizing element is inserted in the optical path, most of the polarized components parallel to the longitudinal direction of the grid are reflected and the orthogonal polarized components pass. Accordingly, the direction of the polarization axis of the irradiated polarized light is a direction orthogonal to the longitudinal direction of the grid of the polarizing element.
As a feature of the wire grid polarizing element, it is known that the dependency of the extinction ratio of polarized light on the incident angle (the angle of light incident on the polarizing element) is small.
In FIG. 12, the structural example of the polarized light irradiation apparatus which combined the rod-shaped lamp and the wire grid polarizing element is shown.
A light irradiation unit 20 including a rod-shaped lamp 21 such as a high-pressure mercury lamp or a metal halide lamp, and a bowl-shaped condensing mirror 22 having an elliptical cross section for reflecting light from the lamp 21, the longitudinal direction of the lamp 21 is a workpiece 40. It arrange | positions so that it may become the width direction (perpendicular to a conveyance direction) of the photo-alignment film | membrane 41 formed on it. The light irradiation unit 20 is provided with a wire grid polarizing element 10. The wire grid polarizing element 10 has a rectangular shape with one side slightly longer than the light emission length of the lamp 21, and is provided such that its longitudinal direction coincides with the longitudinal direction of the lamp 21.

The rod-shaped lamp 21 is arranged so that its longitudinal direction coincides with the longitudinal direction of the bowl-shaped condenser mirror 22, and so that its cross section coincides with the first focal position of the elliptic bowl-shaped condenser mirror 22, The photo-alignment film 41 formed on the workpiece 40 is disposed at the second focal position of the bowl-shaped condenser mirror 22.
The workpiece 40 is, for example, a long continuous workpiece and is wound in a roll shape around the delivery roller R1, drawn out from the delivery roller R1, conveyed, and taken up by the take-up roller R2 under the light irradiation unit 20. It is done.
When the work 40 is transported under the light irradiation unit 20, the light alignment film 41 of the work 40 is irradiated with light from the rod-shaped lamp 21 polarized by the wire grid polarizing element 10 to be subjected to a light alignment process.
In FIG. 12, the grid of the wire grid polarization element 10 is provided in parallel to the longitudinal direction of the rod-shaped lamp 21, and therefore the polarization axis of the polarized light irradiated to the photo-alignment film is in the longitudinal direction of the rod-shaped lamp 21. On the other hand, the direction is orthogonal, that is, the direction parallel to the transport direction of the photo-alignment film.
If the length of the rod-shaped lamp 21 is provided corresponding to the width of the photo-alignment film and the photo-alignment film is moved in one direction relative to the polarized light irradiation device, in principle, one lamp is used. , It is possible to perform an alignment treatment for a long strip-shaped photo-alignment film.
JP 2004-163881 A JP 2004-144484 A JP 2002-328234 A Japanese translation of PCT publication No. 2003-508813

As described above, the wire grid polarizing element has a small incident angle dependency and can also polarize light incident obliquely. However, as a result of experiments conducted by the inventors, polarized light produced by light incident obliquely on the polarizing element has a polarization axis that is rotated as compared to polarized light produced by light incident at an angle close to or perpendicular to the polarization element. It was found that this will be referred to as an axis deviation hereinafter. When the axis deviation occurs in the polarized light, the polarization axis varies in the light irradiation region.
When the optical alignment process is performed with polarized light having a different polarization axis, the contrast of a liquid crystal display element made using the processed alignment film varies depending on the location, causing a problem that the liquid crystal display element appears uneven. For this reason, there is a case where the variation of the polarization axis in the light irradiation region is required to be within 0.1 °.
FIG. 13 shows the relationship between the angle of light incident on the wire grid polarizer and the direction of the polarization axis of polarized light emitted from the polarizing element.
The horizontal axis is the angle of light incident on the wire grid polarizer (incident angle), and the vertical axis is the amount of deviation of the polarization axis of the emitted polarized light.
Assuming that the direction of the polarization axis when the light incident perpendicularly to the polarizer (with an incident angle of 0 °) is polarized and emitted is 0 °, as shown in the figure, the polarization axis increases as the incident angle increases. Rotates, and the shift amount (rotation amount) increases.
For example, the polarization axis of polarized light by light having an incident angle of 50 ° is shifted (rotated) by 6 ° or more with respect to the direction of the polarization axis of polarized light by light having an incident angle of 0 °.
When a light source that emits diffused light such as a rod-shaped lamp is used, light is incident on the polarizing element at various incident angles, and therefore the polarization axis of the polarized light emitted from the polarizing element varies. Therefore, the variation of the polarization axis in the region irradiated with polarized light increases.

FIG. 14 schematically shows components of light incident on the polarizing element from the rod-shaped lamp. In the figure, a rod-shaped lamp 21 indicates the light emission length of the lamp.
As shown in the figure, at the point A on the polarizing element 10 immediately below the light emission long end of the rod-shaped lamp 21, the light component incident obliquely becomes larger than the light component incident vertically. .
As shown in FIG. 13, as the incident angle to the polarizing element 10 increases, the amount of deviation (rotation amount) of the polarization axis increases. Therefore, when the component of light incident obliquely increases, the point A of the polarizing element increases. The axial deviation of the emitted polarized light increases, and the variation of the polarization axis in the light irradiation region increases. In FIG. 14, the point A is described on the polarizing element, but the same description can be made when it is positioned on the light irradiation surface.
Although the case of the rod lamp has been described with reference to FIG. 14, the same problem is caused not only when a linear light source is used like a rod lamp but also when a point light source such as an LED or LD that emits diffused light is used. Alternatively, the same occurs when a planar light source is used.
If the light incident on the polarizing element is parallel light, the angles of the light incident on the polarizing element are aligned, so that there is no axial misalignment of the polarized light due to the difference in incident angle. However, it is difficult to make the diffused light emitted from a linear light source such as a rod-shaped lamp or a planar light source in which a plurality of point-like and linear light sources are arranged into parallel light.
The present invention has been made in order to solve the above-described problems, in which diffused light is incident on a wire grid polarizing element, and the alignment film is irradiated with polarized light emitted from the wire grid polarizing element to perform photo alignment. In the polarized light irradiation device that performs the above, the object is to reduce the variation in the polarization axis of the polarized light emitted from the wire grid polarization element, and to reduce the variation in the polarization axis in the light irradiation region.

As a result of various studies to solve the above problems, the following has been found.
If a light component incident at a certain illuminance and angle is added to a wire grid polarizer at the same illuminance and angle, a light axis incident at a symmetrical angle cancels the polarization axis deviation, and It has been found that polarized light having the same polarization axis is emitted.
That is, in the example of FIG. 13, for example, when light having an incident angle of 50 ° is incident on the polarizing element, the polarization axis is shifted (rotated) by about 6.5 °. When light of 50 ° is added, the amount of deviation (rotation amount) of the polarization axis of the polarized light emitted from the polarizing element becomes 0 °.
This is because when only light having an incident angle of −50 ° is incident on the polarizing element, the polarization axis of the emitted polarized light shifts (rotates) by about −6.5 °, and therefore, the light having an incident angle of −50 ° and −50 This is considered to be because if the light at the same angle is incident at the same time, the two are canceled out and the axis of the polarization axis is eliminated. Therefore, even if there is light incident on the polarizing element obliquely, if light having the same illuminance and symmetrical incident angle is incident, that is, if light is incident on the polarizing element in a balanced manner from all directions. Thus, it has been found that the outgoing polarized light does not cause an axis shift, and therefore the variation of the polarization axis in the light irradiation region can be reduced.

Therefore, by providing auxiliary optical means for allowing light to enter the polarizing element in a balanced manner from all directions, it is possible to reduce the variation in the polarization axis of the emitted polarized light, and to reduce the variation in the polarization axis in the light irradiation region. Can be reduced.
Theoretically, if the vector direction when the vector of light incident on the polarizing element is integrated in all directions is perpendicular to the plane of the polarizing element, variations in the polarization axis can be eliminated. This is considered to be possible, and this means that the light source viewed from the polarizing element is increased infinitely with uniform brightness, or the number is increased infinitely.
The light source cannot be increased infinitely or the number can be increased indefinitely, but if the light source is surrounded by a reflective mirror to reflect light and the image of the light source is artificially increased, the light source viewed from the polarizing element has a uniform brightness. Can be regarded as a large light source.
Therefore, it is conceivable to use a reflection mirror that reflects light from the light source as the auxiliary optical means. When a reflecting mirror is used as the auxiliary optical means, the more the reflecting mirror sides are, the more light source images are reflected. Therefore, if the light source is surrounded by many reflecting surfaces, light is irradiated in a balanced manner from all directions. Such a state can be created.
That is, the light emission port of the light irradiation unit that emits the diffused light is surrounded by the cylindrical reflection mirror, and the light emitted from the cylindrical reflection mirror is incident on the wire grid polarization element.

The following shapes can be considered as the reflection mirror used as the auxiliary optical means.
(A) The shape viewed from the light irradiation surface side, that is, the cross-sectional shape in the direction orthogonal to the central ray of the light irradiated from the light irradiation unit may be a polygon, but the corners are rounded. It is considered desirable to reduce the loss of light at the corners.
(B) As for the cross-sectional shape when cut along the central ray of the light emitted from the light irradiation unit, it is desirable that the widths of the light incident side (light irradiation side) and the light emission side (polarization element side) are equal. . That is, each reflecting surface of the reflecting mirror is preferably parallel to the central ray.
(C) If a light diffusing plate is provided between the light irradiator and the cylindrical mirror, the luminance of the light source is made uniform and the illuminance balance of light incident on the polarizing element is improved.

In the present invention, the following effects can be obtained.
(1) A cylindrical reflection mirror is used as auxiliary optical means, and the diffused light emitted from the light irradiation unit is reflected by the mirror surrounding the emission port of the light irradiation unit. It can be incident in a balanced manner. Accordingly, it is possible to reduce the axial deviation of the polarized light emitted from the polarizing element.
(2) By providing the diffusion plate on the light incident side of the cylindrical mirror, the balance of the illuminance of light incident on the polarizing element can be improved, and the axial deviation can be further reduced.

FIG. 1 is a diagram showing a configuration of a polarized light irradiation apparatus according to a first embodiment of the present invention. FIG. 1A is a sectional view of the polarized light irradiation apparatus according to the present embodiment as viewed from the longitudinal direction of a rod-shaped lamp. (B) is sectional drawing seen from the direction orthogonal to the longitudinal direction of a rod-shaped lamp.
As in FIG. 11, the light irradiation unit 20 includes a rod-shaped lamp 21 such as a high-pressure mercury lamp or a metal halide lamp, which is a linear light source, and a bowl-shaped condenser mirror that reflects light from the lamp 21. Built in. In the following figures including this figure, the rod-shaped lamp 21 indicates the light emission length.
Further, the light irradiation unit 20 is provided with an opening 20a which is a light emission port on the side where the photo-alignment film is disposed, and the direct light from the lamp 21 and the reflected light from the condenser mirror are diffused light. Exit. Here, a rod-shaped lamp will be described as an example of a light source. However, in recent years, LEDs and LDs that emit ultraviolet light have been put into practical use. If such LEDs or LDs are arranged in a straight line, a rod-shaped lamp is used. Can be used as a linear light source. In that case, the direction in which the LEDs or LDs are arranged corresponds to the longitudinal direction of the lamp.
In addition, as materials for photo-alignment films, there are currently known materials that are aligned with light having a wavelength of 260 nm and light with a wavelength of 20 nm, materials that are aligned with light of 280 nm to 330 nm, and materials that are aligned with light of 365 nm. The type is appropriately selected according to the required wavelength.

On the light emitting port 20a side of the light irradiating unit 20, a cylindrical auxiliary optical means (hereinafter referred to as a cylindrical mirror 23) having an inner surface open at both ends and a reflecting surface is provided.
The cylindrical mirror 23 is provided so that the light emission port 20a of the light irradiation unit is surrounded by one open end of the cylindrical mirror 23 so that all the light emitted from the light irradiation unit 20 enters.
The light incident on the cylindrical mirror 23 is reflected directly or by the reflection surface on the inner surface and is emitted from the other open end.
The wire grid polarization element 10 is provided on the side from which the light of the cylindrical mirror 23 is emitted. The light emitted from the cylindrical mirror 23 is polarized by the polarizing element 10 and applied to the photo-alignment film 41.

FIG. 2 is a diagram schematically showing light incident on the wire grid polarization element 10 via the cylindrical mirror 23. The balance of light incident on the wire grid polarizer 10 will be described with reference to FIG. The balance of light incident on the photo-alignment film can be similarly explained.
As shown in the figure, the light source image of the rod-shaped lamp 21 of the light irradiation unit 20 is reflected on the inner reflection surface of the cylindrical mirror 23, and a virtual image of the light source is generated at the position indicated by the dotted line in the figure.
Here, as in FIG. 14, a component of light incident on the polarizing element surface A that hits the end of the rod lamp 21 will be considered. Conventionally, the direct light from the light source only enters the portion A at, for example, an incident angle + δ (solid line b) or + θ (solid line a).
However, by providing the cylindrical mirror 23, the light from the virtual image of the light source reflected on the reflecting surface enters the portion A at an incident angle of −δ (dotted line d) or −θ (dotted line e).
Conventionally, the light from the virtual image is not used because it goes outside the light incident surface of the polarizing element (solid line e, solid line f), but is reflected by the inner reflection surface of the cylindrical mirror and is polarized. Is incident on.
Thereby, light enters the portion A from all directions in a balanced manner, and the axial deviation of the polarized light emitted from the polarizing element is offset. Therefore, the variation of the polarization axis in the light irradiation region is reduced.

FIG. 3 is a diagram showing the results of measuring the variation in the polarization axis of the light irradiation region with and without the cylindrical mirror 23.
In the measurement experiment, the dispersion of the polarization axis in a light irradiation region of 100 mm × 60 mm was measured using one rod-shaped lamp having a light emission length of 125 mm and a wire grid polarizing element.
Note that the polarization axis of the polarized light emitted from the light irradiation unit is a direction orthogonal to the longitudinal direction of the lamp.
FIG. 3B shows a case where a cylindrical mirror 23 having a rectangular parallelepiped shape of 85 mm × 145 mm × 150 mm is provided between the rod-shaped lamp 21 and the polarizing element 10, and FIG. 3A shows this cylindrical mirror. This is a case where 23 is removed.
In both cases, with reference to the direction of the polarization axis immediately below the center in the longitudinal direction of the rod-shaped lamp (center portion of the light irradiation region), the polarization axis rotates toward the peripheral portion of the light irradiation region.
However, in the case of FIG. 3A without the cylindrical mirror, the width of the variation in the polarization axis of the light irradiation region is + 0.92 ° to −0.92 °, which is 1.84 °, compared to FIG. When the cylindrical mirror 23 is provided as shown in FIG. 3B, the variation width is + 0.52 ° to −0.52 °, which is 1.05 °, and the variation width is reduced by nearly 0.8 °. .
As described above, it was confirmed that the variation in the polarization axis was reduced by using the cylindrical mirror 23.

FIG. 4 is a view showing a modification of the first embodiment. In the first embodiment, a light diffusing plate 24 is provided on the light incident side of the cylindrical mirror 23.
As the light diffusing plate 24, for example, quartz glass obtained by frosting (sand slicing), a fluororesin thin plate, or the like can be used.
The light diffusing plate 24 diffuses light from the light source to make the luminance uniform. Therefore, for example, even if a luminance distribution occurs in the longitudinal direction of the rod-shaped lamp 21, the luminance is made uniform by the action of the diffusion plate 24, and the diffusion plate 24 itself becomes a surface light source having uniform luminance.
The inner reflection surface of the cylindrical mirror 23 creates a virtual image of a surface light source with uniform brightness by the light diffusion plate 24, and light with uniform illuminance enters the polarizing element 10 from all directions.
Therefore, the light incident on the polarizing element 10 has a good balance not only with respect to the incident angle but also with respect to the illuminance, and the axial deviation of the emitted polarized light is further reduced. For this reason, the variation in the polarization axis in the light irradiation region can be further reduced.

5 and 6 are diagrams for explaining the balance of light components incident on the polarizing element when the width of the light incident side and the emission side of the cylindrical mirror 23 are different.
If the widths of the light incident side and the light emitting side are different, as shown in the figure, the cross-sectional shape when cut along the optical axis direction of the light irradiated from the light irradiation unit 20 becomes a trapezoid.
FIG. 5 shows a case where the light exit side is wider than the light entrance side of the cylindrical mirror 23. In this case as well, a virtual image of the light source is generated by the inner reflection surface of the cylindrical mirror 23, but the distance r ′ to the light source L ′ of the virtual image is far from the distance r to the light source L of the real image when viewed from the polarizing element 10. Become.
For example, light is incident on the portion B of the polarizing element 10 from a real image light source at an incident angle + θ, and light is incident from a virtual image light source at an incident angle −θ. Therefore, although the incident angles can be balanced, the light source of the light incident at the incident angle −θ is farther than the light source of the light incident at the incident angle + θ, and the illuminance is reduced accordingly.
That is, the incident light is incident on the polarizing element 10 as compared to the case where the illuminance of the incident angle −θ incident on the portion B is different from that of the incident angle + θ and the widths of the light incident side and the output side are the same. The balance of the light component to be deteriorated.
However, by adopting the configuration as shown in FIG. 5, the balance of the components of light incident on the polarizing element 10 is improved and the axial deviation can be reduced as compared with the case where the cylindrical mirror 23 is not provided. Therefore, when the light irradiation area is larger than the area of the light source, it is conceivable to use a cylindrical mirror having such a shape.

FIG. 6 shows a case where the light exit side of the cylindrical mirror 23 is narrower than the light incident side. In this case, the distance r ′ from the polarizing element to the light source of the virtual image is closer to the distance r to the light source of the real image.
Therefore, as in the above case, the illuminance of the incident angle −θ and the incident angle + θ is different, and the illuminance balance is deteriorated.
However, if the light emission side is narrowed, the illuminance of the light irradiation region is increased and the uniformity of the illuminance distribution is also improved. For this purpose, it is conceivable to narrow the emission side.

In the above embodiment, the case of using a rod-shaped lamp has been described. However, the present invention can be similarly applied to a point light source or a surface light source in which a plurality of point light sources are arranged in a plane.
FIG. 7 is a diagram showing the configuration of the polarized light irradiation apparatus according to the second embodiment of the present invention, where FIG. 7A is a view seen from a direction orthogonal to the workpiece conveyance direction, and FIG. It is the figure seen from the direction. In this embodiment, a point light source that emits diffused light, such as an ultra-high pressure mercury lamp or a xenon mercury lamp, is used as the light source. As described above, the light source may be an LED or LD that emits ultraviolet light.
The light irradiation unit 20 includes a lamp 31 such as an ultra-high pressure mercury lamp or a xenon mercury lamp, and an elliptical condenser mirror 32 that reflects light from the lamp 31.
The light irradiating unit 20 is provided with an opening 20a which is a light exit on the side where the photo-alignment film is disposed, and the direct light from the lamp 31 and the reflected light from the condenser mirror 32 are diffused light. To be emitted.
On the light emitting port 20a side of the light irradiating unit 20, as described above, the cylindrical cylindrical mirror 23 whose inner surface opened at both ends is a reflecting surface is provided. The light that has entered the cylindrical mirror 23 is reflected directly or by the reflection surface on the inner surface, exits from the other open end, enters the wire grid polarization element 10, and is polarized by the polarization element 10. The alignment film 41 is irradiated.

FIG. 8 is a diagram schematically showing light incident on the wire grid polarizing element 10 via the cylindrical mirror 23 when a point light source is used.
As shown in FIG. 6A, the light source image of the lamp 31 of the light irradiation unit 20 is reflected on the inner reflection surface of the cylindrical mirror 23, and a virtual image of the light source is generated at the position shown in FIG.
For this reason, the image of the light source seen from the polarizing element 10 (light irradiation surface) appears to be large as shown in FIG. 4B, and light is incident on the polarizing element 10 (light irradiation surface) from all directions in a balanced manner. Can be made. For this reason, as described above, the axial deviation of the polarized light emitted from the polarizing element is canceled out, and the variation of the polarization axis in the light irradiation region is reduced.

FIG. 9 is a view showing a modification of the second embodiment. As shown in FIG. 4, the light diffusion plate 24 is provided on the light incident side of the cylindrical mirror 23 in the second embodiment. It is.
As shown in FIG. 9, by providing the light diffusing plate 24, the inner reflection surface of the cylindrical mirror 23 creates a virtual image of a surface light source with uniform brightness by the light diffusing plate 24. Light with uniform illuminance can be incident from the direction. Therefore, the axial deviation of the emitted polarized light is further reduced, and the variation of the polarization axis in the light irradiation region can be further reduced. Also in the second embodiment, as shown in FIGS. 5 and 6, the width of the light incident side and the emission side of the cylindrical mirror 23 may be different.
In the first and second embodiments, the case where the work as the photo-alignment film is a belt-like work and the optical alignment film is irradiated with polarized light while transporting the belt-like work has been described. The present invention can be similarly applied to an apparatus that has a shape or a circular shape and performs photo-alignment by irradiating the work with polarized light for a predetermined time without moving the work.

Next, the shape of the cylindrical mirror 30 will be described. FIG. 10 is a plan view of the cylindrical mirror 23 as seen from the direction of the light irradiation surface, and shows a cross-sectional shape in a direction orthogonal to the central ray of the light emitted from the light irradiation unit 20.
FIG. 10A shows a case where a linear light source is used as the light source and a cylindrical mirror having a rectangular cross section is used. FIG. 10B shows a case where a linear light source is used as the light source and the corners of the rectangle are curved.
FIG. 10C shows a case where a point light source is used as a light source and a cylindrical mirror having a square cross section is used, and FIG. 10D is a cylindrical shape having a point light source as a light source and a circular cross section. The case where a mirror is used is shown.
In the case of a rectangular shape as shown in FIGS. 10A and 10C, most of the light is reflected by the action of the mirror and reaches the polarizing element, but the light toward the corner is not reflected. Therefore, the balance of the light applied to the polarizing element 10 is slightly deteriorated. From the experimental results shown in FIG. 3, even when the shape is rectangular, the effect of reducing the variation in the polarization axis is sufficiently obtained, and there is not much problem in practical use.
However, in order to further improve the balance of the light applied to the polarizing element, it is conceivable to eliminate the corner where the light does not reflect but disappears. Since the number of reflected light sources increases as the number of sides of the reflecting mirror increases, the cross-sectional shape of the cylindrical mirror 30 can be considered to be a structure having no corners and infinite sides. For example, FIG. As shown in d), the corners may be curved.

  In the above embodiment, the case where one linear light source or point light source is used has been described. However, as described above, a cylindrical mirror may be provided around a surface light source that emits surface light. The effect of can be obtained.

It is a figure which shows the structure of the polarized light irradiation apparatus of 1st Example of this invention. It is a figure which shows typically the light which injects into a wire grid polarizing element via a cylindrical mirror in FIG. It is a figure which shows the result of having measured the dispersion | variation in the polarization axis of a light irradiation area | region with and without a cylindrical mirror. It is a figure which shows the modification of a 1st Example. It is a figure explaining the balance of the component of the light which injects into a polarizing element in case the width | variety of an output side is wider than the light-incidence side of a cylindrical mirror. It is a figure explaining the balance of the component of the light which injects into a polarizing element in case the width | variety of an output side is narrower than the light-incidence side of a cylindrical mirror. It is a figure which shows the structure of the polarized light irradiation apparatus of the 2nd Example of this invention. It is a figure which shows typically the light which injects into a wire grid polarizing element via a cylindrical mirror in FIG. It is a figure which shows the modification of a 2nd Example. It is a figure explaining the example of a shape of a cylindrical mirror. It is a figure which shows the schematic structure of a wire grid polarizing element. It is a figure which shows the structural example of the conventional polarized light irradiation apparatus which combined the rod-shaped lamp and the wire grid polarizing element. It is a figure which shows the relationship between the angle of the light which injects into a wire grid polarizer, and the direction of the polarization axis of the polarized light radiate | emitted from a polarizing element. It is a figure which shows typically the component of the light which injects into a polarizing element from a rod-shaped lamp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wire grid polarizing element 20 Light irradiation part 21 Rod lamp 22 Condensing mirror 23 Cylindrical mirror 24 Light diffusing plate 31 Lamp 32 Condensing mirror

Claims (2)

In a polarized light irradiation apparatus that performs light alignment by irradiating polarized light to an alignment film,
A light irradiation unit having a light source that emits diffused light and provided with an opening through which light from the light source is emitted;
A wire grid polarizing element that polarizes the light emitted from the light emitting section;
A cylindrical mirror provided between the light irradiation unit and the polarizing element, the inner surface surrounding the opening of the light irradiation unit is a reflective surface;
The cylindrical mirror has a cross-sectional shape when cut along a central ray of light irradiated from the light irradiation unit, and the width of the light incident side and the light output side is equal. Irradiation device. The polarized light irradiation apparatus according to claim 1, wherein a light diffusion plate is provided between the light irradiation unit and the cylindrical mirror.

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