JP2013222188A - Ps converter alignment exposure equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide PS converter alignment exposure equipment which is capable of using light conventionally returned to a light source and converted to heat, and to solve the problem that half or more of light is wastefully returned to a light source in single polarized light exposure using a polarization filter comprising a wire grid.SOLUTION: Randomly polarized light 3 emitted from a light source 1 for ultraviolet range short wavelength exposure has a P-wave and an S-wave separated from each other by transmission of the P-wave through a transparent glass plate 4 on which a multilayer film comprising a dielectric diffracting the light at an angle approximating the Brewster angle is vapor-deposited, and by reflection of the S-wave on the transparent glass plate 4. The P-wave has a polarization angle rotated and is emitted from an emission window provided with a λ/2 retardation plate 8, whereby single polarized light having an arbitrary polarization angle can be radiated. The S-wave also has a polarization angle rotated and is emitted from an emission window provided with a λ/2 retardation plate, and thus the P-wave as well as the S-wave are used for exposure and continuous exposure using an arbitrary polarization angle is possible.

Description

Detailed Description of the Invention

The present invention relates to an ultraviolet polarized light exposure apparatus using a birefringent crystal phase difference plate for continuously aligning an alignment film in a liquid crystal display in an arbitrary direction.

In order to align the liquid crystal, a technique of aligning by exposure instead of rubbing the liquid crystal sealing panel contact surface with the liquid crystal has been widespread. It is possible to control the alignment of the liquid crystal layer in a desired direction by exposing the alignment film to polarized light by exposing to linearly polarized light in the ultraviolet region.

In recent years, a liquid crystal display for 3D display in which the scanning lines of the liquid crystal display are aligned so that a phase difference of 45 degrees to the right and a phase difference of 45 degrees to the left is generated for each separation line has become widespread. (Arisawa Plant X Pole)

In order to separate the random light of the light source into single polarized light, a birefringent crystal typified by a Brewster angle fluorite prism is used, and only the P wave is used for exposure, and the S wave is reflected in the prism and is heated. Changes to.

Since the birefringent crystal prism spectroscopic system uses only the P wave, the alignment film can be arbitrarily oriented by rotating the exposure device to an arbitrary angle.

In order to continuously expose an arbitrary orientation to a rolled film, the exposure apparatus needs to have a length longer than the width of the film, and the orientation exposure irradiation at an arbitrary angle in the traveling direction of the rolled film. Must be made against.

The wire grit is an aluminum slit-deposited element, has a function of transmitting P waves in an arbitrary wavelength band and reflecting S waves, and the linear polarization direction can be arbitrarily set by rotating the slit optical axis direction.

By aligning the slit angles of the wire grit rotated to an arbitrary angle with the same angle, the linear polarizing plate having an arbitrary angle that is long with respect to the film width direction can be obtained.

The rolled film can be continuously irradiated with single-polarized exposure light by a long wire grid in which a random-polarized exposure light source is inclined at an arbitrary angle.

However, since the polarization exposure apparatus using a wire grid uses only the P wave for exposure and reflects the S wave and returns it to the light source side, the amount of light is halved. If the light transmittance of the wire grid is 80%, the energy that can be actually used for exposure is less than 40% (0.5 × 0.8 = 0.4) even if the distance from the light source and the diffusion are ignored.

As described in [0004], in order to separate random light from a light source into single polarized light, a birefringent crystal typified by a Brewster angle fluorite prism is used, and only a P wave is used for exposure. In this case, since the transmittance is 95% effective, a single polarized light of about 47.5% (0.5 × 0.95 = 0.475) can be used for exposure, but the P wave is rotated to an arbitrary angle. Since the exposure light source and the birefringent prism are integral with each other, the apparatus itself must be tilted in an arbitrary direction. However, with this method, the exposure machine cannot be arranged on a tangent line perpendicular to the traveling direction of the rolled film.

In order to propose an exposure machine that irradiates an arbitrary polarized light in a tangential direction perpendicular to the traveling direction of the rolled film, the P wave is rotated by an arbitrary angle and the S wave is rotated by an arbitrary angle. A λ / 2 retardation plate is required.

Conventionally, the heat generated by the exposure light source and the short wavelength in the ultraviolet region are high energy, withstood it, and no corresponding retardation plate has been manufactured.
[JP 2012-032730] Exposure apparatus Method of switching orientation direction by switch [JP 2012-018256]
[JP 2011-027968]
[JP 2011-203669]

The present invention transmits P-waves by a transparent glass-like plate on which a multilayer film is deposited by a dielectric material that splits randomly polarized light emitted from a light source for ultraviolet short wavelength exposure at an angle close to the Brewster angle, The S wave is separated by reflecting, and the P wave is made by combining a plurality of crystals with birefringence, such as quartz and sapphire, to a desired thickness to produce a λ / 2 phase difference plate independent of temperature. By rotating the polarization angle from the exit window provided with the λ / 2 phase difference plate and emitting it, single polarized light having an arbitrary polarization angle can be irradiated.

The S wave reflected in the previous section is also reflected again by the reflection mirror, and a temperature-dependent retardation plate of λ / 2 is obtained by polishing and combining a plurality of crystals having secondary refraction such as quartz and sapphire to an arbitrary thickness. The single polarized light having an arbitrary polarization angle can be irradiated by producing and rotating the polarization angle from the exit window provided with the λ / 2 phase difference plate.

When a linearly polarized beam is incident on the ½ phase difference plate described above, it is emitted as a linearly polarized beam. However, the polarization plane is rotated from the incident polarization, and the rotation angle of the polarization plane is twice the angle formed by the incident polarization and the axis of the λ / 2 retardation plate.

A retardation plate made of a birefringent crystal needs to have a low thermal dependency, and therefore must be a zero order type in which the slow axes of a plurality of retardation plates are made to go straight.

A zero-order wave plate is formed by, for example, intersecting the fast axes of two quartz plates at right angles.
The difference in thickness between the two quartz plates determines the rotation angle of the polarized light. A zero-order type wave plate is characterized by being less affected by changes in temperature and wavelength than a multi-order wave plate.

The present invention transmits a P wave by a transparent glass-like plate on which a multilayer film is deposited by a dielectric material that splits randomly polarized light emitted from a light source for ultraviolet short wavelength exposure at an angle close to the Brewster angle. If the transmittance of the P wave that is separated by reflecting the wave and transmits through the transparent glass plate is parallel light, the light absorption is small and the reflectance of the S wave can be reflected with high efficiency. S wave that has been converted into heat by returning to the light source so far by reflecting the S wave with a mirror with a highly reflective dielectric coating and making it the same direction as the light traveling direction of the P wave Can be used for exposure.

A photo-alignment exposure apparatus that polishes a crystal having a birefringence and goes straight to a zero-order type and tilts the λ / 2 retardation plate so that the alignment film to be exposed is oriented at an arbitrary angle is long. The exposure can be continuously performed by emitting exposure light on the tangent of a cylinder whose scale is rolled to the width of the film.

For example, in the case where the right 45 degree λ / 4 phase difference plate and the left 45 degree λ / 4 phase difference plate are exposed and distributed for each scanning line of the flat panel display for 3D display, for example, a film coated with an alignment film A mask window with the width of the scanning line is opened for each separation line (for example, only the even scanning line or only the odd scanning line is opened). Random polarized light incident from the light source is split at an angle close to the Brewster angle. P-waves are transmitted through a transparent glass-like plate on which a multilayer film is deposited by a dielectric, and linearly polarized at a position of 45 degrees by passing through a λ / 2 phase difference plate inclined at a slow axis of 67.5 degrees. Is inclined to reach the mask window A, and the alignment exposure can be performed in a horizontal row on the film from the vacant window. Next, an S wave is reflected by a transparent glass-like plate on which a multilayer film is deposited by a dielectric material that splits at an angle close to the Brewster angle, and is reflected by a mirror by a high-reflectance dielectric coating, and the P wave is reflected. In the same direction as the light travel direction. Then, by passing through the λ / 2 phase difference plate inclined at the slow axis of −22.5 degrees to the outgoing light of the polarized S wave, the linearly polarized light is inclined at the position of −45 degrees and arrives at the mask window B and is freed there. Orientation exposure can be performed in a horizontal row from the window to the film.
The mask A and the mask B may be integrated, and the rolled film has the same tension between the mask A and the mask B. Therefore, there is no danger of misalignment of the scanning line due to expansion and contraction of the film, and the film is continuously oriented. Exposure can be continued.

In the previous section, when the openings of the mask A and the mask B are rectangular with the film width, and the polarized light reaching the mask A and the mask B is the slow axis of the λ / 2 phase difference plate, A is 67.5 degrees, B In the case of 22.5 degrees, when A and B are set to 22.5 degrees, the same linear polarization angle is 45 degrees, so that the orientation for confining the liquid crystal can be continuously exposed with about twice the amount of light.

A short-wavelength P-wave S-wave conversion orienting apparatus including ultraviolet rays, which has strong environmental resistance even when the light source has high energy, and can be used for combining laser beams. Two laser oscillator optical axes such as laser cutting can be synthesized.

The light emitted from the exposure light source 1 on the film 12 wound around the roller 15 passes through the P wave S wave polarization separation transparent glass 4 and the P wave is rotated 45 degrees to the right by the mask A8 by the λ / 2 phase difference plate 6. Figure of exposure and continuous orientation exposure by rotating the S wave 45 degrees to the left with mask B9 The figure which exposes the light which came out of the light source 1 for exposure on the film 12 wound around the roller 15 by rotating the P wave right 45 degree | times with the wire grid 10, and is carrying out orientation exposure continuously. FIG. 2 shows a structure for performing alignment exposure for each scanning line of a flat display for 3D and an enlarged view of a mask window for aligning and exposing a scanning line at 45 degrees to the right by an opening window of the mask, and a wire grid 10 installed on the film side. Direction 11 of the aluminum grid. In FIG. 1, the slow axis of the λ / 2 phase difference plate is tilted to 67.5 degrees for the mask A8, and the slow axis is tilted to -22.5 degrees for the rotated polarization angle of 45 degrees to the right and the mask B9. The figure which rotated the outgoing polarization angle to 45 degrees to the left. The direction of light is drawn on the left with a picture 17 from the front of the screen to the back, and the direction of light in the side view is drawn on the right. Optical path direction arrow 16. The left diagram shows the direction of the slow axis of the phase difference plate A in FIG. 1, and the right diagram shows the direction of the slow axis of the phase difference plate B.

1. 1. Light source for exposure 2. Reflecting mirror for condensing Random polarization 4. 4. P-wave S-wave polarized light separation transparent glass 5. S wave reflection mirror λ / 2 phase difference plate A
7. λ / 2 retardation plate B
8). Mask A
9. Mask B
10. 10. Wire grid 11. Wire grid slit angle Film 13. Direction of film travel 14. Roller rotation direction15. Roller 16. Outgoing light direction 17 Outgoing light rear 18. P wave S wave P wave separated by polarization separation transparent glass 19. λ / 2 retardation plate slow axis angle 20. The outgoing light polarization angle rotated by the λ / 2 phase difference plate 21. 21. S wave separated by P wave S wave polarization separation transparent glass Mask opening window

Claims (3)

An ultraviolet light source, a PS beam splitter element in which a PS separation coat is deposited on a transparent substrate, a reflection mirror that reflects S polarized light separated by the PS beam splitter element, and a crystal having birefringence at the P wave and S wave exit ports An exposure apparatus for photo-alignment characterized by comprising a λ / 2 phase difference plate. The slow axis of the λ / 2 phase difference plate made of the crystal installed at the P wave and S wave exit of claim 1 is used as a mirror with S polarization separated from the P wave transmitted through the PS beam splitter element. The λ / 2 position is characterized in that the reflected S wave is rotated so as to rotate clockwise from 0 ° to 45 ° with respect to each polarization plane, or counterclockwise from 0 ° to 45 °. An exposure apparatus for photo-alignment having a retardation plate arrangement. In the optical alignment apparatus, the P wave transmitted through the PS beam splitter element and the S wave reflected from the PS beam splitter element are reflected by the reflection mirror, and each of the P wave S wave toward the opening is λ. / 2 An exposure apparatus for photo-alignment, characterized in that the polarization angle is rotated by a phase difference plate to produce linearly polarized outgoing light of any polarization angle for both P and S waves.

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