JP5821860B2 - 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, a rod-shaped lamp having a light emission length corresponding to the width of the photo-alignment film is used, and the alignment film or the light source is moved in a direction perpendicular to the longitudinal direction of the lamp while irradiating the light from the lamp with polarization. Then, the alignment film having a large area can be subjected to the optical alignment process in a relatively short time.

FIG. 6 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 Takeda, Nonaka, Fujimoto "Clean Room Environmental Problems Siloxane Compound" Clean Technology April 1998, page 34

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.

In addition, the atmosphere in the clean room of a semiconductor or liquid crystal display element factory where such a polarized light irradiation device is arranged contains a substance called a siloxane compound, which causes manufacturing problems and deterioration of yield. (See, for example, Non-Patent Document 1).
A large amount of a siloxane compound is contained in, for example, a resist developer. When irradiated with ultraviolet rays, the siloxane compound generates white powder by a photochemical reaction, and causes the surface of the optical element inside the ultraviolet irradiation device to become cloudy.
The wire grid polarizing element has a fine grid formed on the surface of a glass substrate or the like, and if a siloxane compound adheres to this surface, it cannot be easily cleaned.

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. In the maintenance of the device, etc., the wire grid polarization element prevents the grid from being broken by touching the grid forming surface of the wire grid polarization element attached to the device or dropping an object. This is to prevent white turbidity due to the siloxane compound from occurring on the surface of the device.
Is to configure the device.

In order to solve the above-described problem, in the polarized light irradiation apparatus provided with the wire grid polarization element, a filter is provided on the opposite side (illuminated object side) from the light source with respect to the wire grid polarization element. A filter that transmits light having a wavelength to be polarized is used.
Further, air that cools the wire grid polarizing element and the filter is flowed between the wire grid polarizing element and the filter while preventing the clouding of the wire grid polarizing element.

Since a filter is provided on the side opposite the light source of the wire grid polarizer (irradiated object side), it is difficult for fingers to touch the wire grid polarizer from the outside of the polarized light irradiation device, preventing damage to the grid. Can do.
In addition, since the filter is provided on the side where the irradiated object (work) is arranged with respect to the wire grid polarizing element, the siloxane compound is less likely to adhere to the surface of the wire grid polarizing element, and white turbidity is unlikely to occur in the wire grid polarizing element. Become. Furthermore, by flowing air between the wire grid polarizing element and the filter, the siloxane compound is less likely to adhere to the surface of the wire grid polarizing element, and the clouding of the wire grid polarizing element is less likely to occur.

It is a figure which shows schematic structure of the lamp house (lamp) of the polarized light irradiation apparatus used as the premise of this invention. It is a figure which shows the structure of a polarizing element unit. It is a figure which shows the modification of the lamp house (lamp) of the polarized light irradiation apparatus used as the premise of this invention. It is a figure which shows schematic structure of the lamp house (lamp) of the polarized light irradiation apparatus of this invention. It is a figure which shows the modification 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 a polarized light irradiation apparatus as a premise 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 the solid arrows in the figure, the light from the lamp 11 is reflected directly or by the reflecting mirror 12, and a wire grid polarizing element 81 and a filter plate 91 disposed at a distance from the polarizing element 81. The workpiece W is irradiated through
The blower 30 generates cooling air that cools the lamp 11, the reflection mirror 12, the wire grid polarizing element 81, the filter plate 91, and the like when the lamp 11 is lit, and the radiator 20 cools the lamp 11, the reflection mirror 12, and the like that are cooled. It works to lower the temperature of the wind.

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.
The cooling air is sent out from the blower 30, passes through the ventilation path 50, and cools the lamp 11 and the reflection mirror 12 from the light emission side of the reflection mirror 12. Further, a part of the cooling air passes through the ventilation path 100 between the wire grid polarizing element 81 and the filter plate 91 to cool the wire grid polarizing element 81 and the filter plate 91. The cooling air that has cooled the lamp 11, the reflection mirror 12, the wire grid polarizing element 81, the filter plate 91, and the like and has reached a high temperature is drawn into the light irradiation unit 10, passes through the radiator 20, and is cooled again. It is sent out by the blower 30. Here, the blower 30 serves as an air supply mechanism for flowing air between the polarizing plate 81 and the filter plate 91.

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 for polarizing light passing therethrough and a filter frame 92 having a filter plate 91 are 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 side opposite to the lamp 11 (work 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

  And the filter unit 90 is arrange | positioned in the position of the light emission opening 70 formed in the outer wall 60 on the opposite side to the light source (the lamp | ramp 11 and the reflective mirror 12) of the polarizing plate 81 (work W side of the polarizing element unit 80). . As with the polarizing plate 81, the filter unit 90 is configured by arranging a plurality of filter plates 91 side by side in the holding frame 92 along the longitudinal direction of the lamp 12. 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.

With this configuration, the polarizing plate 81 is provided inside the outer wall 60 of the lamp house 1, and the filter unit 90 is attached to the light exit port 70 that is an opening formed in the outer wall 60. Yes. Therefore, a finger or the like does not directly touch the polarizing plate 81, and the grid G can be prevented from being damaged.
If the polarizing plate 81 and the filter plate 91 are brought into contact with each other and overlapped, the grid G of the polarizing plate 81 may be damaged. Therefore, the air flow path forming member 93 disposes them with an interval of about 5 mm to 100 mm. This interval forms a ventilation path 100 through which cooling air for cooling the polarizing plate 81 and the filter plate 91 flows.

In this example , the ventilation path forming member 93 stands on the holding frame 92 of the filter plate 91, and the holding frame 82 of the polarizing element unit 80 is attached thereon. However, the ventilation path forming member 93 may stand on the outer wall 60, and the holding frame 82 of the polarizing element unit 80 may be provided thereon.
Further, the ventilation path forming member 93 may be attached to the light irradiation unit 10 and the holding frame 82 of the polarizing element unit 80 may be suspended. In short, it is only necessary to form a ventilation path through which cooling air flows between the light irradiation unit 10 and the polarizing element unit 80 and between the polarizing element unit 80 and the holding frame 92 of the filter plate 91.

If the distance between the polarizing plate 81 and the filter plate 91 is narrow, it is difficult for the cooling air to flow between them, and there is a possibility that the polarizing plate 81 and the filter plate 91 are heated by the heat from the lamp 11. Provide a flow interval. However, in order to protect the grid G, it is desirable to set an interval so that the finger does not reach the grid G forming surface of the polarizing plate 81.
An example of the interval where the finger does not enter is the IP (International Protection) standard. This is established in IEC 60529 (1989) and JIS C0920 (1993). As a protection content for the human body, in the case of a finger, the protection content for a device should be 12.5 mm or less in diameter. It is shown. Therefore, the distance between the polarizing plate 81 and the filter plate 91 is preferably 5 mm to 12.5 mm.

A plurality of ventilation path forming members 93 are provided on both sides (left and right direction in FIG. 1) along the longitudinal direction of the polarizing element unit 80 and the filter 90 with a space through which cooling air can pass.
The ventilation path forming member 93 may be a rod-shaped member or a rectangular block-shaped member. Further, it may be a plate or wall having a through-hole (preferably having a diameter of 5 mm or more) through which the cooling air can pass, or a net-like one as long as the distance between the polarizing element unit 80 and the filter 90 can be maintained. good.
When a plate-like member or a net-like member having a through hole is formed, the diameter of the hole or net serving as a vent hole is 12.5 mm or less (that is, a size that does not allow a finger to enter) (that is, If the gap between the polarizing element unit 80 and the filter 90 is widened to allow sufficient cooling air to flow, the grid G of the polarizing plate 81 can be obtained. The finger cannot reach the formation surface, and the grid G can be protected.

  Further, since the filter plate 91 is provided on the side on which the workpiece W (object to be irradiated) is arranged with respect to the wire grid polarization element 81, the siloxane compound may directly touch and adhere to the surface of the wire grid polarization element 81. Less. As a result, white turbidity is less likely to occur in the wire grid polarizing element 81. Furthermore, since cooling air (air) flows between the wire grid polarizing element 81 and the filter plate 91, the siloxane compound is less likely to adhere to the surface of the wire grid polarizing element 81. Therefore, white turbidity is hardly caused by the wire grid polarizing element 91.

  As shown in FIG. 1, the width of the wire grid polarizing element 81 close to the light source side (here, the width is perpendicular to the length direction of the linear light source and parallel to the light irradiation surface). If the width of the filter plate 91 far from the light source side is wider than the width of the filter plate 91, the light incident on the filter plate 91 from the light source will not be kicked by the holding frame 82 of the polarizing plate 81. Light emitted from the light source can be used effectively.

FIG. 3 is a view showing a modified example of the polarized light irradiation apparatus as a premise of the present invention. The difference from the polarized light irradiation apparatus shown in FIG. 1 is that the grid G forming surface of the polarizing plate 81 is directed not to the filter plate 91 but to the light source. The other configuration is basically the same as that shown in FIG.
In the present embodiment, the grid G forming surface of the polarizing plate 81 faces the light source side, but the polarizing plate 81 itself is provided inside the outer wall 60 of the lamp house 1 and formed on the outer wall 60. A filter unit 90 is attached to the light exit port 70. Therefore, a finger or the like does not directly touch the polarizing plate 81, and the grid G can be prevented from being damaged.
Similarly to the above example , the presence of the filter plate 91 and the cooling air (air) flowing between the filter plate 91 and the polarizing plate 81 prevent adhesion of the siloxane compound to the polarizing plate 81, and the polarizing plate 81. Can be prevented.

FIG. 4 is a diagram showing a schematic configuration of a lamp house (lamp) of the polarized light irradiation apparatus of the present invention. This figure is a cross-sectional view in a direction perpendicular to the longitudinal direction of the lamp house as in FIG.
The difference between the example of the configuration of FIG. 1, the polarizing element unit 80 is disposed at a position of the light exit 70 of the lamp house 1 is that placing the full Irutayunitto 90 outside of the outer wall 60 of the lamp house 1.

The filter frame 92 of the filter unit 90 is supported by a ventilation path forming member 93 erected on the outer wall 60, and the ventilation path 100 is formed between the polarizing plate 81 and the filter plate 91.
A blower nozzle 110 that supplies air to the ventilation path is provided outside the lamp house 1. The air from the blowing nozzle 110 passes through the ventilation path 100 between the polarizing plate 81 and the filter plate 91, thereby preventing the siloxane compound from adhering to the polarizing plate 81, thereby preventing white turbidity of the polarizing plate 81.
Further, since the filter unit 90 is provided on the work side (light emitting side) of the polarizing element unit 80, the finger G or the like does not directly touch the polarizing plate 81, and the grid G can be prevented from being damaged.

FIG. 5 is a diagram showing a modification of the embodiment of the present invention. The difference from the polarized light irradiation apparatus shown in FIG. 4 is that the grid G forming surface of the polarizing plate 81 is directed to the light source side instead of the filter plate 91 side. The other configuration is basically the same as that shown in FIG.
Even with this arrangement, the filter unit 90 is provided on the work side (light emitting side) of the polarizing element unit 80, so that the finger G or the like does not directly touch the polarizing plate 81 and the grid G is prevented from being damaged. Can do.

  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 Ventilation path forming member 100 Ventilation path 110 Blowing nozzle 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,
A filter that transmits polarized light on the opposite side to the light source of the wire grid polarizing element is provided on the outside of the outer wall ,
A polarized light irradiation apparatus comprising an air supply mechanism for flowing air between the wire grid polarization element and the filter. The wire grid polarizing element is larger than the filter when viewed in a width direction that is perpendicular to a length direction of the linear light source and parallel to a light irradiation surface. The polarized light irradiation apparatus according to 1.

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