JP2022031802A - Light irradiation device and exposure apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light irradiation device for an exposure apparatus which can perform photo-alignment treatment with a simple configuration.

SOLUTION: A light irradiation device 10 comprises: a light source 12 having a plurality of LEDs 16; a polarization element 14 that receives light rays L from the light source 12, and irradiates a workpiece X with the transmitted light rays L; and an optical filter 30 that selectively transmits light rays L with a predetermined wavelength or longer, out of the light rays L emitted from the light source. An optical axis CL of each LED 16 is set to form a first angle θ1 with respect to the workpiece X, and a second angle θ2, which is equal to a half of the light distribution angle of the light rays L emitted from each LED 16, is set to be smaller than the first angle θ1. In addition, the optical filter 30 is arranged so as to be parallel to the workpiece X, and is characterized in that the transmittance of the light rays L with a predetermined wavelength or longer increases as an incident angle at which the light rays L having a predetermined wavelength or longer enter the optical filter 30 becomes larger.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a light irradiation device mainly used for exposure when manufacturing a liquid crystal panel, and an exposure device including the light irradiation device.

When a liquid crystal is used as a TN type display panel, it does not operate normally only by enclosing the liquid crystal between two glass substrates and applying a voltage to the transparent electrodes formed on the inner surfaces of these glass plates. This is because the liquid crystal molecules are in a disjointed state.

In order for the liquid crystal to operate in the normal TN method, it is necessary to orient the liquid crystal molecules in a certain direction and to make the rising direction of the liquid crystal molecules constant. Specifically, the liquid crystal molecules are oriented in a direction tilted by about 3 ° with respect to the glass substrate, and this tilt angle is called a pretilt angle.

Then, of the pair of glass substrates having liquid crystal alignment performance, one glass substrate is arranged so as to be oriented in the X direction, and the other glass substrate facing the other is arranged in the Y direction orthogonal to the X direction. (TN method)

As described above, the liquid crystal alignment treatment is required for the production of the liquid crystal panel, and the rubbing treatment for physically rubbing the surface of the glass substrate has been conventionally performed (for example, Patent Document 1). This rubbing treatment is a treatment method for forming a film capable of orienting liquid crystal molecules in a certain direction by rubbing an organic polymer film formed on a glass substrate with a cloth having long hairs in a predetermined direction. Is.

With the spread of rubbing processing and the generalization of the TN method, which has a fast response speed, LCD panels can be mass-produced at low cost with stable performance, and are used for display monitors and game machines for OA equipment such as personal computers. There is a history that LCD monitors have become widespread as monitors.

However, the rubbing method has problems related to reliability, such as poor uniformity, the possibility of electrostatic breakdown of the TFT, and adhesion of powder dust generated during rubbing.

In addition, the pre-tilt angle that can be achieved by the rubbing method is about 3 ° in the TN method that represents the horizontally oriented liquid crystal mode as described above, and it constitutes a liquid crystal mode display panel that supports high-speed response with low voltage drive. There was a difficulty in doing so.

In order to deal with such a problem of the rubbing method, an exposure machine capable of performing photoalignment processing has been proposed at present, and an attempt is made to use this exposure machine in a long arc mercury lamp as a light source.

Japanese Unexamined Patent Publication No. 2007-17475

However, it is considered that there is a problem in the exposure machine using the long arc mercury lamp. Generally, the exposure material is set to have photosensitive characteristics so as to react to light in a specific wavelength band, but when looking at the spectral characteristics of the light from a mercury lamp, the light is composed of many emission lines of mercury rays. You can see that there is.

For this reason, when a mercury lamp is used as a light source for exposure, a large amount of light has a wavelength outside the photosensitive characteristics of the exposure material, so that the exposure material may be overexposed by light having a wavelength outside the photosensitive wavelength band. It is thought that there is.

Of course, it is possible to cut light rays with wavelengths outside the photosensitive characteristics (short wave side and long wave side) by the selective wavelength reflection film, but a narrow band cut filter (bandpass filter) is required and high accuracy is required. As a result, the cost of the device is increased.

In addition, since the light emitted from a long-arc mercury lamp is diffused over a wide area, it is difficult to control the irradiation angle of the light from the mercury lamp, which is important for performing photoalignment processing. For example, a method of blocking excess light with a louver or the like. However, in this case, there is another problem that the utilization efficiency of the light emitted from the mercury lamp is lowered.

Furthermore, there is also a method of irradiating the glass substrate with collimated (parallelized) light at an angle, but this method has the problem that the equipment is large and expensive because the optical system is complicated. Conceivable.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a light irradiation device for an exposure device capable of performing a light alignment process with a simple configuration.

According to one aspect of the invention
A light source with multiple LEDs and
A polarizing element that receives light from the light source and irradiates the work with the transmitted light.
It is equipped with an optical filter that selectively transmits light having a predetermined wavelength or higher among the light radiated from the light source.
The optical axis of each of the LEDs has a first angle tilted with respect to the work.
The second angle, which is half the light distribution angle of the light emitted from each of the LEDs, is smaller than the first angle.
The optical filter is arranged so as to be parallel to the work.
The optical filter is characterized in that the transmittance of the light having a predetermined wavelength or more is increased as the incident angle of the light having a predetermined wavelength or more with respect to the optical filter is increased. Equipment is provided.

According to other aspects of the invention
A light source with multiple LEDs and
A polarizing element that receives light from the light source and irradiates the work with the transmitted light.
It is provided with a cover member that transmits light from the light source.
The optical axis of each of the LEDs has a first angle tilted with respect to the work.
The second angle, which is half the light distribution angle of the light emitted from each of the LEDs, is smaller than the first angle.
The polarizing element has a surface on which a wire grid is formed.
The cover member is arranged at a position facing the forming surface of the polarizing element.
The space between the cover member and the forming surface is hermetically sealed.
A light irradiation device is provided in which the polarizing element and the cover member are arranged so as to be parallel to the work.

Preferably,
The light irradiation device further includes a translucent plate arranged in parallel with the work between the light source and the polarizing element.

According to other aspects of the invention
An exposure apparatus including the above-mentioned light irradiation apparatus is provided.

According to the light irradiation device according to the present invention, the optical axes of a plurality of LEDs are tilted by a first angle with respect to the work, and a second angle corresponding to half of the orientation angle of the light emitted from each LED is set. By setting it smaller than the first angle, all the light emitted from each LED is directed toward the optical axis side of the LED rather than the perpendicular line from the LED to the work.

As a result, it has become possible to provide a light irradiation device for an exposure device capable of performing a light alignment process having a simple configuration and an effective irradiation angle and a large amount of light.

It is a figure which shows the light irradiation apparatus 10 which concerns on 1st Embodiment to which this invention was applied. It is a figure which shows the light irradiation apparatus 10 which concerns on the 2nd Embodiment to which this invention was applied. It is a figure which shows the light irradiation apparatus 10 which concerns on 3rd Embodiment to which this invention was applied. It is a graph for demonstrating the light transmission characteristic of an optical filter 30. It is a figure which shows the light irradiation apparatus 10 which concerns on 4th Embodiment to which this invention was applied. It is a figure which shows the light irradiation apparatus 10 which concerns on modification 1. FIG. It is a figure which shows the light irradiation apparatus 10 which concerns on modification 1. FIG. It is a figure which shows the light source 12 which concerns on the modification 2. It is a figure which shows the light source 12 which concerns on the modification 2. It is a figure which shows the light source 12 which concerns on the modification 2.

(Structure of the light irradiation device 10 according to the first embodiment)
The light irradiation device 10 according to the first embodiment to which the present invention is applied will be described below. The light irradiation device 10 is used by being incorporated in the exposure device mainly for exposure when manufacturing a liquid crystal panel. As shown in FIG. 1, the light irradiation device 10 generally includes a light source 12 and a polarizing element 14.

The light source 12 is a member that irradiates the exposure light L toward the exposure surface A on which the work (exposure object) X is placed, and a plurality of LEDs 16 are used in the first embodiment. Since these LEDs 16 irradiate the work X moving in a certain direction on the exposure surface A with the exposure light L so as to scan, the light sources 12 are plurality of in the direction orthogonal to the moving direction of the work X. It is formed by arranging the LEDs 16 of the above in substantially series.

Further, each LED 16 constituting the light source 12 has a first angle θ1 (that is, an incident angle θ1) with respect to the work X so that the optical axis CL of these LEDs 16 has a first angle θ1 (that is, an incident angle θ1) with respect to the work X (that is, an exposed surface). It is arranged at an angle (relative to A). By using an alignment film created by irradiating light with little variation in the angle component from an angle to the liquid crystal panel, it is possible to make a stable pretilt angle and orientation state appear, and the liquid crystal panel in any orientation mode can be used. realizable.

Further, the second angle θ2, which is half the light distribution angle of the light L emitted from each LED 16, is set to be smaller than the above-mentioned first angle θ1.

The polarizing element 14 is an element that transmits and polarizes only a light component that vibrates in one direction among the light emitted from the light source 12, and in the first embodiment, a wire grid polarizing element is used. The wire grid polarizing element has a wire grid formed on one surface of a transparent substrate (glass substrate). In this first embodiment, the formation surface 18 of the wire grid may be the surface of the polarizing element 14 on the light source 12 side or the surface opposite to the light source 12. Further, it is preferable that the polarizing element 14 is arranged so as to be parallel to the work X (exposed surface A).

(Effect of the light irradiation device 10 according to the first embodiment)
According to the light irradiation device 10 according to the first embodiment, the optical axes CL of the plurality of LEDs 16 are tilted by the first angle θ1 with respect to the work X, which corresponds to half of the orientation angle of the light L emitted from each LED 16. By setting the second angle θ2 to be smaller than this first angle θ1, all the light L emitted from each LED 16 is directed toward the optical axis CL side of the LED 16 rather than the perpendicular line from the LED 16 toward the work X. become.

This makes it possible to provide a light irradiation device 10 for an exposure device capable of performing a light alignment process having a simple configuration and an effective irradiation angle and a large amount of light.

(Structure of the light irradiation device 10 according to the second embodiment)
As shown in FIG. 2, the light irradiation device 10 according to the second embodiment is a light irradiation device 10 according to the above-mentioned first embodiment to which a light transmitting plate 20 is added.

The light-transmitting plate 20 is, for example, a glass plate that transmits light L from the light source 12, and is arranged in parallel with the work X between the light source 12 and the polarizing element 14. It is preferable that the surface (both sides) of the translucent plate 20 is not subjected to antireflection treatment such as an antireflection film.

(Effect of the light irradiation device 10 according to the second embodiment)
According to the light irradiation device 10 according to the second embodiment, among the light L radiated from the light source 12, the light L having a large incident angle θ3 with respect to the translucent plate 20 is reflected on the surface of the translucent plate 20 and is therefore a polarizing element. It will not reach 14 or Work X.

As a result, the incident angle of the light L reaching the work X with respect to the work X can be limited to a predetermined value or less, so that a more stable optical orientation process of the pretilt angle can be realized.

(Structure of the light irradiation device 10 according to the third embodiment)
As shown in FIG. 3, the light irradiation device 10 according to the third embodiment generally includes a light source 12, a polarizing element 14, and an optical filter 30.

Similar to the first and second embodiments, the light source 12 is a member that irradiates the exposure light L toward the exposure surface A on which the work X is placed, and a plurality of LEDs 16 are used. Since these LEDs 16 irradiate the work X moving in a certain direction on the exposure surface A with the exposure light L so as to scan, the light sources 12 are plurality of in the direction orthogonal to the moving direction of the work X. It is formed by arranging the LEDs 16 of the above in substantially series.

In the light irradiation device 10 according to the third embodiment, it is not necessary to specify the first angle θ1 and the second angle θ2 as in the first and second embodiments, and the first angle θ1 and the second angle θ2 are not required. The angle θ2 of is arbitrary. Of course, the first angle θ1 and the second angle θ2 may be defined as in the first and second embodiments.

The polarizing element 14 is an element that transmits and polarizes only a light component that vibrates in one direction among the light emitted from the light source 12, and the wire grid polarizing element is used as in the first and second embodiments. ..

The surface 18 for forming the wire grid may be the surface of the polarizing element 14 on the light source 12 side or the surface opposite to the light source 12. Further, it is preferable that the polarizing element 14 is arranged so as to be parallel to the work X (exposed surface A).

The optical filter 30 is arranged between the light source 12 and the polarizing element 14, and is a member that selectively transmits light L having a predetermined wavelength or more among the light L emitted from the light source 12 and has a surface surface. A wavelength selection film is formed on the surface. Further, it is preferable that the optical filter 30 is arranged so as to be parallel to the work X (exposed surface A) like the polarizing element 14. As the optical filter 30, if the conditions described below are satisfied, a long-pass filter that transmits light of a predetermined wavelength or higher, or a long-pass filter that transmits light in a predetermined wavelength range and has a longer wavelength and a shorter wavelength than that of the optical filter 30 are transmitted. A bandpass filter that blocks light of wavelength can be used. Further, the optical filter 30 may be arranged on the side opposite to the light source 12 side of the polarizing element 14.

Here, the optical filter 30 has an angle dependence, the incident angle θ1 of the light entering the optical filter 30 becomes large, and the wavelength region of the light transmitted through the optical filter 30 is on the low wavelength side. It will spread. An example of this is shown in FIG. For example, when considering light at 325 nm, when the incident angle θ1 of light with respect to the optical filter 30 is 0 ° (that is, when the light is incident perpendicular to the optical filter 30), the transmittance of light at 325 nm is about 5%. be.

Then, when the incident angles of the light of 325 nm with respect to the optical filter 30 are increased to 15 °, 30 °, and 45 °, the transmittance of the light of 325 nm increases to 15%, 70%, and 95%.

Utilizing such properties of the optical filter 30, the transmittance of the light L having a predetermined wavelength or more increases as the incident angle θ1 of the light L having a predetermined wavelength or more with respect to the optical filter 30 increases. By setting to increase the light L, light L having a desired wavelength or higher can be sufficiently transmitted at the incident angle (first angle θ1) to the optical filter 30 corresponding to the desired pretilt angle.

(Effect of the light irradiation device 10 according to the third embodiment)
According to the light irradiation device 10 according to the third embodiment, among the light L emitted from the light source 12, the light L having a small incident angle θ1 on the optical filter 30 (light incident substantially perpendicular to the optical filter 30). Is difficult to pass through the optical filter 30, and exposure can be performed centering on the light L close to the desired incident angle θ1 with respect to the work X, so that a more stable pretilt angle can be obtained.

(Structure of the light irradiation device 10 according to the fourth embodiment)
As shown in FIG. 5, the light irradiation device 10 according to the fourth embodiment generally includes a light source 12, a polarizing element 14, and a cover member 40.

Similar to the above-described embodiment, the light source 12 is a member that irradiates the exposure light L toward the exposure surface A on which the work X is placed, and a plurality of LEDs 16 are used. Since these LEDs 16 irradiate the work X moving in a certain direction on the exposure surface A with the exposure light L so as to scan, the light sources 12 are plurality of in the direction orthogonal to the moving direction of the work X. It is formed by arranging the LEDs 16 of the above in substantially series.

In the light irradiation device 10 according to the fourth embodiment, it is not necessary to specify the first angle θ1 and the second angle θ2 as in the first and second embodiments, and the first angle θ1 and the second angle θ2 are not required. The angle θ2 of is arbitrary. Of course, the first angle θ1 and the second angle θ2 may be defined as in the first and second embodiments.

The polarizing element 14 is an element that transmits and polarizes only a light component that vibrates in one direction among the light emitted from the light source 12, and the wire grid polarizing element is used as in the first and second embodiments. ..

The surface 18 for forming the wire grid may be the surface of the polarizing element 14 on the light source 12 side or the surface opposite to the light source 12. Further, it is preferable that the polarizing element 14 is arranged so as to be parallel to the work X (exposed surface A).

The cover member 40 is, for example, a glass plate that transmits light L from the light source 12, and is arranged substantially parallel to the work X at a position facing the formation surface 18 of the wire grid in the polarizing element 14. That is, when the formation surface 18 of the wire grid in the polarizing element 14 is formed on the side opposite to the light source 12 side as shown in the drawing, the cover member 40 is also arranged on the side opposite to the light source 12 side in the polarizing element 14. To. On the contrary, when the formation surface 18 of the wire grid in the polarizing element 14 is formed on the light source 12 side (not shown), the cover member 40 is also arranged on the light source 12 side in the polarizing element 14.

The surface (both sides) of the cover member 40 may not be subjected to antireflection treatment such as an antireflection film, but it is preferable to perform antireflection treatment such as an antireflection film on one or both surfaces. be.

Further, it is preferable that the space S between the cover member 40 and the formation surface 18 of the wire grid in the polarizing element 14 is sealed. For example, a holding frame 42 for holding the peripheral edges of the cover member 40 and the polarizing element 14 may be provided, and the holding frame 42 may seal the space S between the cover member 40 and the wire grid forming surface 18 of the polarizing element 14. Conceivable.

The above-mentioned "sealing" means that a minute solid substance such as a siloxane compound does not enter the space S, and "sealing" in a complete sense is not necessary.

Further, it is preferable to use a so-called "reflection type" wire grid for the polarizing element 14. In the case of the "reflection type", the wire grid is heated by the light L from the light source 12, and the temperature of the enclosed space is unlikely to be damaged by the formation surface 18 of the wire grid. Is.

Further, for the purpose of cooling the sealed space S, the members constituting the space S such as the cover member 40, the polarizing element 14, or the holding frame 42 may be cooled by a method such as forced air cooling or water cooling.

(Structure of the light irradiation device 10 according to the fourth embodiment)
According to the light irradiation device 10 according to the fourth embodiment, since the cover member 40 is arranged at a position facing the formation surface 18 of the wire grid in the polarizing element 14, for example, when the light irradiation device 10 is maintained. It is possible to prevent the wire grid forming surface 18 from being accidentally damaged, and to prevent the wire grid forming surface 18 from being contaminated with fine solid matter such as a siloxane compound.

(Modification 1)
The configurations of the light irradiation devices 10 according to the first to fourth embodiments described above can be combined with each other. For example, by combining the optical filter 30 of the third embodiment and the cover member 40 of the fourth embodiment, as shown in FIG. 6, the optical filter 30, the polarizing element 14, and the cover member are sequentially arranged from the side closest to the light source 12. The light irradiation device 10 in which the 40 is arranged can be formed.

Of course, the positions of the polarizing element 14 and the cover member 40 may be reversed to form the light irradiation device 10 in which the optical filter 30, the cover member 40, and the polarizing element 14 are arranged in order from the side closest to the light source 12.

Furthermore, as shown in FIG. 7, the optical filter 30 is arranged at the position closest to the work, and the cover member 40, the polarizing element 14, and the optical filter 30 are arranged in this order from the side closest to the light source 12. The device 10 may be formed.

(Modification 2)
Further, as shown in FIG. 8, the lens 50 for controlling the light distribution angle of the light L from the LED 16 with respect to the light source 12 used in the light irradiation device 10 according to the first to fourth embodiments described above. May be further provided. The number of the lenses 50 may be one or two or more as shown in the figure.

Further, as shown in FIG. 9, the reflector 52 for controlling the light distribution angle of the light L from the LED 16 with respect to the light source 12 used in the light irradiation device 10 according to the first to fourth embodiments described above. May be further provided.

Further, as shown in FIG. 10, the lens 50 and the reflector 52 may be combined to control the light distribution angle of the light L from the LED 16.

The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. The scope of the present invention is shown by the scope of claims, not the description described above, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

10 ... Light irradiation device, 12 ... Light source, 14 ... Polarizing element, 16 ... LED, 18 ... Wire grid forming surface 20 ... Translucent plate 30 ... Optical filter 40 ... Cover member, 42 ... Holding frame 50 ... Lens, 52 ... Reflector X ... Work (exposed object), A ... Exposed surface, L ... Light for exposure, CL ... Optical axis (of LED16), θ1 ... First angle, θ2 ... Second angle, θ3 ... (Translucent plate) Angle of incidence (to 20), S ... Space (between the cover member 40 and the forming surface 18 of the wire grid)

Claims (4)

A light source with multiple LEDs and
A polarizing element that receives light from the light source and irradiates the work with the transmitted light.
It is equipped with an optical filter that selectively transmits light having a predetermined wavelength or higher among the light radiated from the light source.
The optical axis of each of the LEDs has a first angle tilted with respect to the work.
The second angle, which is half the light distribution angle of the light emitted from each of the LEDs, is smaller than the first angle.
The optical filter is arranged so as to be parallel to the work.
The optical filter is characterized in that the transmittance of the light having a predetermined wavelength or more is increased as the incident angle of the light having a predetermined wavelength or more with respect to the optical filter is increased. Device. A light source with multiple LEDs and
A polarizing element that receives light from the light source and irradiates the work with the transmitted light.
It is provided with a cover member that transmits light from the light source.
The optical axis of each of the LEDs has a first angle tilted with respect to the work.
The second angle, which is half the light distribution angle of the light emitted from each of the LEDs, is smaller than the first angle.
The polarizing element has a surface on which a wire grid is formed.
The cover member is arranged at a position facing the forming surface of the polarizing element.
The space between the cover member and the forming surface is hermetically sealed.
A light irradiation device characterized in that the polarizing element and the cover member are arranged so as to be parallel to the work. The light irradiation device according to claim 1 or 2, further comprising a light transmitting plate arranged in parallel with the work between the light source and the polarizing element. An exposure apparatus including the light irradiation apparatus according to any one of claims 1 to 3.

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