JP5825392B2 - Polarized light irradiation device - Google Patents

Description

  The present invention relates to a polarized light irradiation apparatus that performs alignment by irradiating polarized light of a predetermined wavelength onto an alignment film of a liquid crystal element, an alignment layer of a viewing angle compensation film, and the like, and more particularly, polarized light irradiation using a wire grid polarizing element. Relates to the device.

In recent years, a technique called photo-alignment has been adopted in which alignment is performed by irradiating polarized light with a wavelength in the ultraviolet region for alignment processing of alignment films for liquid crystal display elements such as liquid crystal panels and alignment layers for 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.
With the increase in size of the liquid crystal panel, the photo-alignment film has an increased area, for example, a square having a side of 2000 mm or more.

Polarized light that combines a rod-shaped lamp, which is a linear light source, and a polarizing element having a wire-grid grid (hereinafter referred to as a wire-grid polarizing element) to perform photo-alignment on the large-area photo-alignment film as described above. A light irradiation apparatus is proposed in Patent Document 1, for example.
A rod-shaped lamp having a relatively long light emission length can be made. Therefore, if a rod-shaped lamp having a light emission length corresponding to the width of the photo-alignment film is used and the alignment film is moved in a direction perpendicular to the longitudinal direction of the lamp while irradiating the light from the lamp with polarization, The alignment film having a large area can be photo-aligned in a relatively short time.

FIG. 4 shows a configuration example of a conventional polarized light irradiation apparatus in which a rod-shaped lamp that is a linear light source and a wire grid polarization element are combined.
In the figure, a work W that is a photo-alignment film is a strip-like long work such as a viewing angle compensation film, for example, and is sent from a feed roll R1, and is photo-aligned by irradiation with polarized light while being conveyed in the direction of the arrow in the figure. Processed and taken up by take-up roll R2.
The light irradiation unit 10 of the polarized light irradiation apparatus includes a rod-shaped lamp 11 that emits light (ultraviolet rays) having a wavelength necessary for photo-alignment processing, such as a high-pressure mercury lamp or a metal halide lamp obtained by adding another metal to mercury, and the rod-shaped lamp. 11 is provided with a bowl-shaped reflecting mirror 12 that reflects the ultraviolet rays from 11 toward the workpiece W. As described above, the length of the rod-shaped lamp 11 is such that the light emitting unit has a length corresponding to the width in the direction orthogonal to the conveyance direction of the workpiece W.

The light irradiation unit 10 is arranged so that the longitudinal direction of the lamp 11 is in the width direction of the workpiece W (a direction orthogonal to the transport direction).
A wire grid polarizing element 81 that is a polarizing element is provided on the light emitting side of the light irradiation unit 10. The light from the light irradiation unit 10 is polarized by the wire grid polarizing element 81 and irradiated to the workpiece W conveyed under the light irradiation unit 10 to perform a photo-alignment process.
The wire grid polarization element is formed by forming a grid (line and space) on a transparent substrate (for example, a glass substrate) that transmits light having a wavelength to be polarized. For example, Patent Document 2 and Patent Document 3 have details thereof. It is shown.

When a wire grid polarization element is inserted in the optical path, most of the incident light that is parallel to the longitudinal direction of the grid is reflected or absorbed, and the polarized component that is orthogonal to the longitudinal direction of the grid passes. Therefore, the light that has passed through the wire grid polarization element becomes polarized light having a polarization axis in a direction orthogonal to the longitudinal direction of the grid of the polarization element.
For the photo-alignment treatment, polarized light in the ultraviolet region is used. In order to make the light incident on the wire grid polarization element into polarized light, the width and spacing of the grid formed on the transparent substrate must be shorter than the wavelength of the polarized light (for example, 100 nm).
For this reason, a fine processing technique is required to form the grid, and the lithography technique and etching technique used for manufacturing semiconductor integrated circuits are used. The size of the work that can be processed by the lithography apparatus and etching apparatus used there. Has its limits. Therefore, the wire grid polarizing element cannot be made large, and the size that can be manufactured at present is up to about 300 mm in diameter.

  Therefore, for example, in Patent Document 4, when a large (long) polarizing element corresponding to a rod-shaped light source having a long light emission length, for example, a rod-shaped high-pressure mercury lamp or a metal halide lamp having a length of 1 m to 3 m is necessary, It has been proposed that a plurality of wire grid polarization elements are aligned and arranged in the frame along the longitudinal direction of the lamp and used as one polarization element unit.

JP 2011-145382 A JP 2002-328234 A Japanese translation of PCT publication No. 2003-508813 Japanese Patent No. 4506212

As described above, the grid of the wire grid polarizing element is manufactured by fine processing, and the width and interval of the grid are, for example, 100 nm. Therefore, if the finger is accidentally touched or an object is dropped on the grid structure, It will break and will no longer serve as a polarizing element. However, since it is fine, it is difficult for the naked eye to see that a grid is formed on the surface of the transparent substrate (glass).
Therefore, during maintenance and inspection of the polarized light irradiation device, it touches the grid forming surface of the polarizing element attached to the device, or drops something on the polarizing element, It may be possible to break the fine grid.

  The present invention has been made in consideration of the above-described problems, and an object of the present invention is a polarized light irradiation apparatus including a linear light source and a wire grid polarizing element that polarizes light from the light source. By configuring the device so that it does not break the grid by touching the grid forming surface of the wire grid polarizing element attached to the device or dropping an object during maintenance of the device, etc. is there.

  In order to solve the above-mentioned problem, the grid forming surface of the wire grid polarizing element used in the polarized light irradiation device is arranged facing the light source. That is, in the lamp house constituting the light irradiation unit, the surface of the wire grid polarizing element on which the grid is not formed is directed to the outside of the lamp house (lamp).

  Further, a filter for protecting the grid forming surface is provided immediately above the grid forming surface of the wire grid polarizing element (between the polarizing element and the light source). A filter that transmits light having a wavelength to be polarized is used.

Since the grid forming surface of the wire grid polarization element faces the light source, the grid forming surface is not touched from outside the lamp house. Even if the polarizing element is touched, the grid is not broken because the surface facing the outside of the lamp house is not the grid forming surface.
In addition, by providing a filter directly above the grid formation surface, for example, even when the inside of the lamp house is being maintained, it becomes difficult to touch the grid surface, and even if an object is dropped, the filter forms the grid. Prevent falling to the surface. This will not break the grid.

1 is a diagram illustrating a schematic configuration of a lamp house (lamp) of a polarized light irradiation apparatus according to a first embodiment of the present invention. It is a figure which shows the structure of a polarizing element unit. It is a figure which shows schematic structure of the lamp house (lamp) of the polarized light irradiation apparatus of the 2nd Example of this invention. It is a figure which shows the structural example of the conventional polarized light irradiation apparatus.

FIG. 1 is a diagram showing a schematic configuration of a lamp house (lamp) of the polarized light irradiation apparatus according to the first embodiment of the present invention. This figure is a cross-sectional view in a direction perpendicular to the longitudinal direction of the lamp house. In the figure, the configuration of the lamp lighting device is omitted.
The lamp house 1 includes a light irradiation unit 10, and a water-cooled cooler (radiator) 20 and a blower (blower) 30 on the light irradiation unit 10. The light irradiation unit 10 includes a lamp 11 and a reflection mirror 12 that reflects light from the lamp 11. As indicated by solid arrows in the figure, the light from the lamp 11 is reflected directly or by the reflecting mirror 12 and is irradiated onto the workpiece W via the wire grid polarizing element 81.
The blower 30 generates cooling air that cools the lamp 11 and the reflecting mirror 12 when the lamp 11 is lit, and the radiator 20 serves to lower the temperature of the cooling air that has cooled the lamp 11 and the reflecting mirror 12.

The light irradiation unit 10 is surrounded by a partition wall 40, and the outer wall 60 of the lamp house 1 covers the outside. A gap is formed between the partition wall 40 and the outer wall 60. This gap becomes the ventilation path 50 through which the cooling air passes.
As shown by the dotted line in the figure, the cooling air is sent out from the blower 30, passes through the ventilation path 50, and is drawn from the light emission side of the reflection mirror 12 into the light irradiation unit 10 while cooling the lamp 11 and the reflection mirror 12. Then, it passes through the radiator 20, is cooled, and is sent out by the blower 30 again.

Further, a light emission port 70 through which light irradiated from the light irradiation unit 10 toward the workpiece W passes is formed in the outer wall 60 of the lamp house 1.
A polarizing element unit 80 having a wire grid polarizing element 81 that polarizes light passing therethrough is attached to the light exit port 70.
The wire grid polarizing element 81 of the polarizing element unit 80 is obtained by forming a wire grid (hereinafter also referred to as a grid) G on one surface of a transparent substrate (glass substrate) that transmits light having a wavelength for performing optical alignment processing. It is. Here, the formation surface of the grid G is arranged facing the lamp 11 side.
In FIG. 1, the grid G of the wire grid polarizing element 81 extends in the horizontal direction of the drawing.

FIG. 2 is a diagram showing the structure of the polarizing element unit 80. 2A is a plan view of the polarizing element unit 80, FIG. 2B is a side sectional view of the polarizing element unit 80, and FIG. 2C is a perspective view of the polarizing element unit 80.
The polarizing element unit 80 includes a plurality of wire grid polarizing elements (hereinafter also referred to as polarizing plates) 81 arranged and held in a frame (holding frame) 82 along the longitudinal direction of the rod-shaped lamp 12 (left and right direction in FIG. 2). It is. The holding frame 82 holds the polarizing plates 81 from above and below.

A gap of about 1 mm to 2 mm is provided between adjacent polarizing plates. In order to align the direction of the grid G between the polarizing plates, the polarizing plate 81 is rotationally moved using this gap to adjust the position. This gap is covered with a light shielding plate 83 in the polarizing element unit 80 so that non-polarized light does not leak from here.
As described above, each wire grid polarizing element (polarizing plate) 81 is arranged so that the grid G is formed on the lamp (light source) side (inside the lamp house) as shown in FIG. The

FIG. 3 is a diagram showing a schematic configuration of a lamp house (lamp) of the polarized light irradiation apparatus according to the second embodiment of the present invention. Similar to FIG. 1, FIG. 3 is a cross-sectional view in a direction orthogonal to the longitudinal direction of the lamp house.
The difference from the configuration of the first embodiment of FIG. 1 is that a filter 90 for protecting the grid G surface of the polarizing plate 81 is disposed on the polarizing element unit 80 (on the lamp side). Like the polarizing plate 81, the filter 90 has a plurality of filter plates 91 arranged in a holding frame 92 along the longitudinal direction of the lamp 12. As indicated by solid arrows in the figure, the light from the lamp 11 is reflected directly or by the reflecting mirror 12 and is applied to the workpiece W through the filter 90 and the polarizing plate 81.

The filter plate holding frame 92 has a support rod 93 placed on the holding frame 82 of the polarizing element unit 80 and is mounted thereon. As the filter plate 91, a quartz plate that transmits the wavelength of polarized ultraviolet light can be used. Moreover, you may use the interference filter which formed the interference which interrupts | blocks visible light and infrared rays which are not required for a photo-alignment process.
Since the grid G of the polarizing plate 81 may be damaged when the filter plate 91 is brought into contact with the polarizing plate 81 and overlapped, the two are arranged with a gap therebetween. If this interval is narrow, it is difficult for the cooling air to flow on the polarizing plate 81, and the polarizing plate 81 may be heated by the heat from the lamp 11. Therefore, a sufficient interval for the cooling air to flow is provided. However, if the interval is too large, the grid G forming surface of the polarizing plate 81 cannot be protected, so it is desirable that the interval be such that a finger cannot enter.

  In the above-described embodiment, a rod-shaped lamp is described as an example of the light source. However, the present invention can be applied to a configuration in which LEDs that emit ultraviolet rays are arranged in a plurality of lines.

1 Lamphouse
DESCRIPTION OF SYMBOLS 10 Light irradiation part 11 Rod-shaped lamp 12 Reflection mirror 20 Radiator (cooling machine)
30 Blower (blower)
40 Partition 50 Ventilation path 60 Outer wall 70 Light exit 80 Polarizing element unit 81 Wire grid polarizing element (polarizing plate)
82 Polarizing plate holding frame 83 Shading plate 90 Filter unit 91 Filter plate 92 Filter plate holding frame 93 Support rod G Wire grid W Workpiece

Claims (2)

In a polarized light irradiation apparatus comprising a linear light source, a polarizing element that polarizes light from the light source, and an outer wall that covers the light source and forms a light exit port through which light from the light source passes,
The polarizing element is a wire grid polarizing element in which a wire grid is formed on a transparent substrate,
The wire grid polarization element is disposed so as to block the light exit port with the surface on which the wire grid is formed facing the inside of the device.
The polarized light irradiation device has a mechanism for circulating cooling air through the enclosed space inside the polarized light irradiation device ,
The said wire grid polarizing element absorbs the polarized light component parallel to the longitudinal direction of a grid among incident light, The polarized light irradiation apparatus characterized by the above-mentioned. The polarized light irradiation apparatus according to claim 1, wherein a filter that transmits light is provided between the wire grid polarization element and the light source.

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