JP2000147506A - Light illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable irradiation in a large area and to determine the alignment direction and pretilt angle of an alignment layer by designing the illuminating device in the manner that the light transmitted through a polarizer irradiates at a specified angle from the normal line of a stage where a substrate is mounted. SOLUTION: The polarizer is positioned at a first polarizer 33. When the illuminating device is observed from the x-z side, the light emitted from the optical system is tilted at a specified angle from the normal line of the substrate for the tilted exposure so that an alignment layer 25 is irradiated with partially polarized light at a specified angle. The pretilt angle of the liquid crystal molecules on the alignment layer 25 is controlled by the energy of the light irradiating the alignment layer 25, the material of the alignment layer and the polarization degree of the illuminating device. On the other hand, the alignment direction of the liquid crystal molecules is controlled by the direction of irradiation light in the tilted exposure. The usable angle θ of the light is preferably 0 to 45 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light irradiating apparatus, and more particularly to a large-area light irradiating apparatus used in a process of optical alignment of a liquid crystal display device.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device comprises upper and lower substrates which are opposed to each other at a predetermined interval by a spacer, and a liquid crystal layer formed between the upper and lower substrates. The upper and lower substrates hold electrodes of a predetermined pattern on their opposing surfaces, and an alignment film for determining the alignment of the liquid crystal is formed on the electrodes.

As an alignment method for treating the alignment film, there are:
Rubbing method or photo-alig
nment method) is used.

In the rubbing method, polyimide (PI, p
olyimide) is a method of applying mechanical alignment with a rubbing cloth after applying an alignment material to bring the alignment direction of the liquid crystal. Is what it is.

However, there is a problem that the arrangement of the liquid crystal molecules is not constant because the shape of the fine grooves formed in the alignment film is changed according to the frictional strength, and thus irregular phase distortion is caused. And light scattering may occur, which may degrade the performance of the liquid crystal display device. In addition, dust and static electricity generated during the rubbing process cause a reduction in yield, and when a pixel is divided to implement a multi-domain, repeated photolithography (photol) is performed.
In the ithography process, it is difficult to realize the reliability and stability of the alignment film.

On the other hand, the photo-alignment step is a method of irradiating ultraviolet rays onto a substrate on which a photo-alignment film is applied to bring a pretilt and an alignment direction of a liquid crystal. There is no danger, which can help reduce yield. In addition, since liquid crystal molecules can be uniformly arranged over the entire alignment film, it is possible to prevent the occurrence of phenomena such as phase distortion and light scattering.

In particular, there is an advantage that it is possible to actually realize a liquid crystal display device having an optical viewing angle by dividing pixels.

The light irradiating device used in the photo-alignment process as described above has been proposed in Japanese Patent Application Laid-Open Nos. 10-90684 (1998.4.10) and 10-161126 (1998.6.19). is there.

FIG. 1 is a schematic view showing the structure of a conventional light irradiating device described in the above-mentioned Japanese Patent Publication No. 10-90684. The conventional light irradiating device includes a polarizing film on an alignment film of a liquid crystal display element. The present invention relates to an apparatus for irradiating polarized light for photo-alignment of an alignment film for irradiating the irradiated light.

Looking at the structure and operation, light including ultraviolet light emitted from the light source (1) is condensed by the condenser mirror (2), reflected by the first reflector (3), and collected. The light enters the optical lens (5). Through the shutter (4)
The light flowing from the condenser lens (5) is reflected by the second reflecting mirror (6).
Are reflected by the collimating lens (7), become parallel light by the collimating lens (7), and enter the polarizing element (8). The polarizing element (8) has a plurality of glass plates (8a) arranged in parallel at an interval, and the glass plate (8a) is inclined so as to form a Brewster angle with respect to incident light. It is arranged and reflects most of the S-polarized light that has transmitted the P-polarized light. The P-polarized light emitted from the polarizing element (8) is applied to the substrate (35) via the mask (13).

[0011] In the light irradiation apparatus configured as described above,
The polarization ratio (s / p, s: vertical polarization, p: horizontal polarization) is set to 0.1 or less, and light is applied to the alignment film of the liquid crystal display device by irradiating polarized light with a constant polarization direction. It is excellent in transmittance, wavelength dependency, durability, lifetime, etc., compared with other existing devices. However, in order to manufacture a large-area liquid crystal display element, the glass plate (8a) of the polarizing element (8) must be manufactured relatively large. There is a problem that the range of the polarization ratio is not appropriate.

FIG. 2 is a schematic diagram showing the configuration of a conventional light irradiation device described in the above-mentioned Japanese Patent Application Laid-Open No. 10-161126. Optical mirror (2), collimating lens (7) and multi-lens (1
9), a condenser lens (5), and one or more reflecting mirrors (3) for guiding light generated from the light source (1) to a substrate (35).
In the exposure apparatus provided with (6), at least one of the reflecting mirrors is constituted by a reflective diffraction grating that mainly reflects the first polarized light.

Since the first reflecting mirror (3) generally has a smaller area than the second reflecting mirror (6), when the first reflecting mirror (3) is formed of a predetermined diffraction grating, the first reflecting mirror (3) has a smaller area. There are advantages that a diffraction grating can do. At this time, since the predetermined diffraction grating is located in front of the multi-lens (19), it is possible to prevent the diffraction grating from affecting the output light of the multi-lens.

With the above configuration, the light irradiating device irradiates the light reflected by the reflection type diffraction grating that mainly reflects the first polarized light, thereby collectively polarizing the polarized light over a large area. Can be irradiated.

[0015] However, the polarization characteristics of the diffraction grating in the light irradiation device have a large wavelength dependence.

The above-mentioned prior arts are focused only on adding a polarizing means to an existing light irradiation device to realize polarized light. There is a problem that there is.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and can irradiate a large area. An object of the present invention is to provide a light irradiation device that determines an angle.

[0018]

In order to achieve the above object, a light irradiation device according to the present invention comprises an optical system, a first polarizer for polarizing light from the optical system, and a light output from the first polarizer. The emitted light is irradiated so as to be inclined at a predetermined angle (θ) with respect to the normal of the stage on which the substrate is placed.

The optical system includes a light source, a lens, and a reflecting mirror, and the reflecting mirror may include one or more. Further, a second polarizer may be provided between the lens and the reflecting mirror, and a third polarizer may be provided if necessary.

In order to achieve the above object, a light irradiation device according to the present invention comprises a light source and a first light source for reflecting light from the light source.
A reflecting mirror, a multi-lens formed of a plurality of lenses, a second reflecting mirror for reflecting light from the multi-lens, and a view for converting the light from the second reflecting mirror into parallel light. A quasi-lens, and a first to polarize light from the collimating lens
The light flowing from the polarizer and the first polarizer is irradiated so as to be inclined at a predetermined angle (θ) with respect to the normal of the stage on which the substrate is placed.

The light irradiation device may further include a second polarizer between the first reflecting mirror and the multi-lens lens, or may include a third polarizer between the multi-lens lens and the second reflecting mirror. Include in addition.

The first polarizer preferably has a high transmittance for light having a wavelength of 200 nm to 800 nm, and preferably has a transmittance of 250 nm.
Those having a wavelength of m to 400 nm and a high transmittance are preferable.

The first polarizer has a polarization degree of 0 to 1, preferably 0.2 to 0.95.

The angle (θ) is preferably in the range of 0 ° to 45 °.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A light irradiation device according to the present invention will be described below in detail with reference to the drawings.

FIGS. 3 and 4 show yz of the light irradiation apparatus of the present invention.
And xz side view.

The light irradiation device of the present invention comprises a light source (1), a condenser mirror (2), a first reflector (3), a lens (37),
Multi-lens (19), second reflector (6), collimator lens (7), mask (13)
, A stage (11) on which a substrate (35) is placed, and a polarizer.

The condenser mirror (2) adjusts the light from the light source (1) so as to be directed to the first reflecting mirror (3), and has a plurality of homogenizers (fly eye lenses) (19). And refracts light so that light passing through each of the lenses overlaps. Second reflector (6)
Reflects the light flowing from the multi-lens lens (19), and the collimating lens (7) converts the light reflected by the second reflecting mirror (6) into parallel light on the substrate (35). To the alignment film (25) formed on the substrate. The collimating lens (7) can be a mirror or a lens, and the multi-lens can be either convex or concave.

In the light irradiation device of the present invention, the polarizer is arranged at the position of the first polarizer (33), and if necessary, in front of the multi-lens (the position of the second polarizer (31)) and / or Can be configured at least one later in a position (not shown).

The polarizer comprises a laminated quartz substrate, a laminated glass substrate, a multi-coated substrate, or the like, and preferably has good heat resistance and durability, and has little wavelength dependence. The laminated quartz or glass substrate is placed at a Brewster angle with respect to the substrate.
le, θ = tan ^-1 n, n: a material inclined to the refractive index of quartz or glass. Therefore, the Brewster angle is 57-60 °
Range. The laminated quartz or glass substrate is
Light can be uniformly radiated when irradiating a large area, and a multi-coated substrate is a substrate in which an inorganic film is coated on a substrate, and the inorganic film is mainly SiO ₂ .

The polarizer preferably has a high transmittance in the wavelength range of 200 to 800 nm, and more preferably has a high transmittance in the wavelength range of 250 to 400 nm.

[0032] Is partially polarized in the range 0∠PD∠1
And preferably in the range of 0.2 / PD / 0.95. Then, an appropriate polarization degree can be selected depending on the type of the alignment film (25).

As shown in FIG. 4, the light irradiation device is
When viewed from the side, the light emitted from the optical system (100)
Due to the oblique exposure of light, it is tilted at a certain angle with respect to the normal of the substrate, and the direction of the maximum transmission axis in the light irradiation device is defined by the plane of the optical path (xz ) Perpendicular to or parallel to Therefore, with the above-described configuration, the partially polarized light of the alignment film (25) can be irradiated obliquely.

FIG. 5 is an xz side view showing the control of the pretilt angle of the alignment film in the light irradiation apparatus of the present invention. Alignment film (2
5) In the above, the pretilt angle (θp) of the liquid crystal molecule (27) is
It is adjusted by the amount of energy of the light applied to the alignment film (25), the material of the alignment film, and the degree of polarization of the light irradiation device. On the other hand, the orientation direction of the liquid crystal molecules (27) is determined by the direction of light irradiation during the oblique exposure.

At this time, the usable light irradiation angle (θ)
Is preferably in the range of 0 ° to 45 °, and if the angle (θ) of the light irradiation is 45 ° or more, the gap between the mask (13) and the alignment film (25) ( Since the effect due to the error of the gap) is maximized, the error of the pattern position on the alignment film due to the pattern of the mask increases.

The following table shows the pattern position error depending on the light irradiation angle (θ) when the gap error between the mask and the alignment film is 20 μm.

[0037]

[Table 1]

FIGS. 6, 7 and 8 show first, second and third views showing the control of the alignment direction of the alignment film in the light irradiation apparatus of the present invention.
It is an xy side view of an Example, and the thick solid arrow in the figure shows the orientation direction of a board | substrate. The solid line rectangle indicates the first position (45) of the substrate, and the dashed line square indicates the second position (47) of the substrate.

As described above, in the apparatus of the present invention, since the alignment direction is determined by the direction of light irradiation during oblique exposure, the direction of light irradiation on the substrate, that is,
The azimuth angle of light is important. This method of adjusting the azimuth of light is shown in FIGS.

As in the first embodiment shown in FIG. 6, a mono-domain or a multi-domain is used.
In the manufacture of the liquid crystal display device of (1), the alignment direction is 0 ° or 90 ° (45 ° or 135 °) with respect to the major axis direction of the substrate.
°), the substrate may be rotated by 90 °, so that the optical system (100) is 0 ° with respect to the major axis direction of the substrate.
Alternatively, they are arranged so as to be located in the direction of 45 °.

That is, when an arbitrary alignment direction including the above-described alignment direction is to be formed, the second embodiment shown in FIG.
The third embodiment is preferably arranged as in the third embodiment, and is preferably the embodiment shown in FIG. In FIG. 7, the required orientation direction can be easily formed by rotating the stage (11) on which the substrate is placed at a predetermined angle (φ). However, in the above arrangement, when manufacturing a multi-domain liquid crystal display element, it is necessary to keep the gap between the mask and the substrate because the mask must be rotated together. In FIG. 8, by moving the optical system (100) to a predetermined angle (φ), a first alignment direction and a second alignment direction due to the movement of the optical system are formed, and the polarization direction in the region of the liquid crystal cell becomes
A multi-domain in which two or more are mixed can be realized.

FIG. 9 is an xz side view showing an exposure area of an alignment film in the light irradiation apparatus of the present invention.

When a mask is used for manufacturing a multi-domain liquid crystal display element, the mask (13) and the substrate (3) are used.
5) A constant gap (d) must be maintained between the upper alignment film (25) and the gap (30 μm).
m to 100 μm is preferred.

As shown in the figure, when the light incident at a predetermined light irradiation angle (θ) passes through the mask (13) and irradiates the alignment film (25), the exposed area becomes Since it is moved by about Δx (Δx = dtan θ) with respect to the angle of the light irradiation, it is formed by being moved by the pattern of the mask (13) or the above numerical value.

Accordingly, in the substantial photo-alignment step, a certain gap is accurately measured between the mask (13) and the substrate (35), and the substrate is determined by considering the measured gap and the angle of light irradiation. Is moved from the initial alignment state and light irradiation is essential.

In order to perform the above, an apparatus for measuring a gap is required during the above process, and the gap is measured using an auxiliary light source for measurement such as a laser. At this time, the gap measurement position is selected from 3 to 4 positions to measure the gap, and a fine position-dependent gap correction device is provided at the lower stage of the stage (11) to reduce the gap error between the measurement positions. To perform the photo-alignment process more precisely.

[0047]

According to the light irradiation apparatus of the present invention, the substrate to be irradiated with the polarizer is arranged so as to be inclined at a predetermined angle, and the partially polarized light is obliquely irradiated to the substrate.
The orientation direction and the pretilt angle of the orientation film can be determined for one irradiation.

Further, in order to manufacture a multi-domain liquid crystal display device, the gap between the mask and the substrate is precisely measured,
By forming a uniform pattern on the alignment film, a large-area and multi-domain liquid crystal display device can be effectively realized.

[Brief description of the drawings]

FIG. 1 is a schematic view of a conventional light irradiation device.

FIG. 2 is a schematic diagram of another conventional light irradiation device.

FIG. 3 is a yz side view of the light irradiation device of the present invention.

FIG. 4 is an xz side view of the light irradiation device of the present invention.

FIG. 5 is an xz side view showing control of a pretilt angle of an alignment film in the light irradiation device of the present invention.

FIG. 6 is an xy side view of the first, second and third embodiments showing the control of the alignment direction of the alignment film in the light irradiation device of the present invention.

FIG. 7 is an xy side view of the first, second and third embodiments showing the control of the alignment direction of the alignment film in the light irradiation apparatus of the present invention.

FIG. 8 is an xy side view of the first, second and third embodiments showing the control of the alignment direction of the alignment film in the light irradiation device of the present invention.

FIG. 9 is an xz side view showing an exposure region of an alignment film in the light irradiation device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Condensing mirror 3 First reflecting mirror 4 Shutter 5 Condensing lens 6 Second reflecting mirror 7 Collimator lens 8 Polarizing element 8a Glass plate 10 Orientation microscope 11 Stage 13 Mask 19 Multi-eye type Lens (homogenizer) 25 Alignment film 27 Liquid crystal molecule 31 Second polarizer 33 First polarizer 35 Substrate 37 Lens 41 First alignment direction 43 Second alignment direction 45 First position of substrate 47 Second position of substrate 100 Optical system

Continuing on the front page (72) Inventor Song Byung-deok, Korea, Korea, Gyeonggi-do, Anyang-si, Dongan-gu, Hugye-dong, Mugyeon-do Promotion Apartment 502-401 Garton apartment 8-805 F term (reference) 2H090 LA05 LA09 LA12 LA16 LA20 MA15 MB14

Claims (43)

[Claims] 1. An optical system, a first polarizer for polarizing light from the optical system, and a light emitted from the first polarizer at a predetermined angle with respect to a normal to a stage on which a substrate is placed. A light irradiation device, which is irradiated so as to be inclined to θ). 2. The light irradiation device according to claim 1, wherein the optical system includes a light source, a lens, and a reflecting mirror. 3. The light irradiation device according to claim 2, wherein the reflecting mirror comprises one or more. 4. The light irradiation device according to claim 1, comprising a glass substrate on which the first polarizer is laminated, a quartz substrate on which the first polarizer is laminated, or a multi-coated substrate. 5. The light irradiation apparatus according to claim 4, wherein the laminated glass substrate and the laminated quartz substrate are laminated at a Brewster angle with respect to the substrate. 6. The multi-coated substrate,
The light irradiation device according to claim 4, wherein the inorganic film is coated. 7. The light irradiation device according to claim 2, wherein a second polarizer is additionally provided between the lens and the reflecting mirror. 8. The light irradiation apparatus according to claim 7, comprising a glass substrate on which the second polarizer is laminated, a quartz substrate on which the second polarizer is laminated, or a multi-coated substrate. 9. The light irradiation apparatus according to claim 7, wherein the glass substrate on which the second polarizer is laminated and the quartz substrate on which the second polarizer is laminated are laminated at a Brewster angle with respect to the substrate. 10. The light irradiation apparatus according to claim 7, wherein the multi-coated substrate is coated with an inorganic film. 11. The light irradiation device according to claim 1, wherein the first polarizer adds light having a wavelength of 200 nm to 800 nm. 12. The light irradiation apparatus according to claim 11, wherein the first polarizer adds light having a wavelength of 250 nm to 400 nm. 13. The light irradiation device according to claim 1, wherein the first polarizer has a degree of polarization of 0 to 1. 14. The light irradiation device according to claim 1, wherein the first polarizer has a degree of polarization of 0.2 to 0.95. 15. The light irradiation device according to claim 1, wherein the angle (θ) is 0 to 45 °. 16. The light irradiation device according to claim 1, wherein the stage rotates. 17. The light irradiation device according to claim 1, wherein the optical system rotates. 18. The light irradiation apparatus according to claim 1, wherein a multi-domain is implemented by additionally including a mask on the substrate. 19. The light irradiation apparatus according to claim 18, wherein a constant gap is maintained between the mask and the substrate. 20. A light source, a first reflecting mirror for reflecting light from the light source, a multi-lens lens composed of a plurality of lenses, a second reflecting mirror for reflecting light from the multi-lens lens, A collimating lens for converting the light from the second reflecting mirror into parallel light, a first polarizer for polarizing the light from the collimating lens, and a light flowing from the first polarizer. A light irradiating device that irradiates the light so as to be inclined at a predetermined angle (θ) with respect to a normal of a stage on which the light is placed. 21. The light irradiation apparatus according to claim 20, further comprising a second polarizer between the first reflecting mirror and the multi-lens type lens. 22. The light irradiation apparatus according to claim 20, further comprising a third polarizer between the multi-lens and the second reflecting mirror. 23. The light irradiation device according to claim 20, wherein the first polarizer partially polarizes the light from the collimating lens. 24. The light irradiation device according to claim 20, wherein the first polarizer transmits light having a wavelength of 200 nm to 400 nm. 25. The light irradiation device according to claim 24, wherein the first polarizer transmits light having a wavelength of 250 nm to 400 nm. 26. The light irradiation device according to claim 20, wherein the first polarizer has a degree of polarization of 0 to 1. 27. The light irradiation device according to claim 26, wherein the first polarizer has a degree of polarization of 0.2 to 0.95. 28. The light irradiation device according to claim 20, wherein the angle (θ) is in a range of 0 to 45 °. 29. The stage according to claim 20, wherein the stage rotates.
The light irradiation device according to claim 1. 30. The light irradiation device according to claim 20, wherein the optical system rotates. 31. The light irradiation apparatus according to claim 20, wherein a multi-domain is implemented by additionally including a mask on the substrate. 32. The light irradiation apparatus according to claim 31, wherein a constant gap is maintained between the mask and the substrate. 33. The light irradiation device according to claim 32, further comprising a gap measuring device for measuring the gap. 34. The light irradiation device according to claim 32, further comprising a gap correction device for correcting the gap. 35. The light irradiation apparatus according to claim 20, wherein the first polarizer is a laminated glass substrate, a laminated quartz substrate, or a multi-coated substrate. 36. The light irradiation device according to claim 35, wherein the laminated quartz or glass substrate is inclined at a Brewster angle with respect to the substrate. 37. The light irradiation apparatus according to claim 35, wherein the multi-coated substrate is coated with an inorganic film. 38. The light irradiation device according to claim 21, wherein the second polarizer is a laminated glass substrate, a laminated quartz substrate, or a multi-coated substrate. 39. The light irradiation apparatus according to claim 38, wherein the laminated quartz or glass substrate is inclined at a Brewster angle with respect to the substrate. 40. The light irradiation apparatus according to claim 38, wherein the multi-coated substrate is coated with an inorganic film. 41. The light irradiation apparatus according to claim 22, wherein the third polarizer is a laminated glass substrate, a laminated quartz substrate, or a multi-coated substrate. 42. The light irradiation apparatus according to claim 41, wherein the laminated quartz or glass substrate is inclined at a Brewster angle with respect to the substrate. 43. The light irradiation apparatus according to claim 41, wherein the multi-coated substrate is coated with an inorganic film.