TWI649515B - Polarized illumination system and polarized illumination modulation method - Google Patents

Abstract

The invention provides a polarized light illumination system and a polarized illumination modulation method. The polarized light illumination system comprises a microwave electrodeless lamp, a quadric reflector housing, a polarization conversion device and a wire grid polarizing element, wherein the microwave electrodeless lamp is located at a focus of the quadric reflector housing, and the polarization conversion device and the wire grid polarizing element are in turn Located directly below the microwave induction lamp. The invention adopts the microwave electrodeless lamp splicing to realize the polarized light irradiation field of view of the large field of view, and improves the static uniformity and integral uniformity of the illumination system by utilizing the adjustability of the microwave-free electrodeless lamp; and the polarized light conversion device is used to illuminate the polarized light. The system's light polarization direction is modulated to improve energy utilization, thereby achieving large field of view, high illumination polarized illumination.

Description

Polarized illumination system and polarized illumination modulation method

The invention provides a field of optical alignment devices, in particular to provide a polarized illumination system and a polarized illumination modulation method.

Optical alignment devices are a type of photoactive alignment film that is incident on a TFT or CF substrate by using polarized UV light, so that photochemical reactions (photocrosslinking, photodecomposition, and photoinduced) occur only in the photosensitive layer that is aligned or perpendicular to the polarization direction of the UV line. Heterogeneous, etc., to make the alignment film anisotropic, and then use the resulting directional anchoring energy (mainly corner anchoring energy) to induce liquid crystal molecules to be uniformly oriented at a certain angle in the plane of the alignment film. As the size of the liquid crystal panel increases, the size of the alignment film is also increasing, and the size of the exit spot of the alignment device is also required to be large. The illumination optical system is the core module of the optical alignment device and is the energy source of the device. The illumination output of the illumination system determines the light intensity value of the working surface of the device, which is an important parameter of the device yield; in addition, the illumination uniformity of the illumination system is determined. The uniformity of the incident light intensity of the alignment film determines the accuracy of the dose control during the processing of the device.

The use of a quadric reflector housing to collect the light emitted by the rod-shaped light source and use the wire grid polarizing element to polarize the light emitted by the light source is one of the illumination schemes of the optical alignment device. As shown in Fig. 1, it is mainly composed of a rod-shaped light source 11, a quadric reflector housing 12, and a wire grid polarizing polarizer 13. The light emitted by the rod-shaped light source 11 is collected by the quadric reflector housing 12 and then collected. The wire grid polarizing polarizer 13 is polarized and then irradiated onto the alignment film 14a on the surface of the workpiece 14. The substrate stage 15 carries the alignment film 14a in the polarization direction (arrow direction in the drawing), and the alignment film 14a is linearly polarized. Irradiation serves the purpose of optical alignment. During the gate polarization process on the device, most of the incident polarization (S light) parallel to the length of the grid is reflected or absorbed, and only the polarization component (P light) perpendicular to the length of the grid is transmitted by the subsequent optics. The system utilizes a large amount of energy loss. In addition, for large-sized liquid crystal polarizing film processing, the rod-shaped light source 11 of the above-described scheme generally has a size of 1.5 m or more, and the long rod-shaped light source 11 introduces high cost and system adjustment in the process of manufacturing and assembling. Degree of freedom, resulting in equipment cost and overall equipment performance risk.

The use of a high-pressure mercury lamp as a light source, collimating the light emitted by the light source, and polarizing it for use in subsequent systems is another optical solution for the alignment optical system. The polarized light illumination device shown in Fig. 2 is mainly composed of a bubble-shaped high-pressure mercury lamp 21, a curved spherical reflector casing 22, a polarizing element 24, and a collimator lens group 26. The unpolarized light emitted from the bubble high-pressure mercury lamp 21 is collected by the curved spherical reflector 22, and the first mirror 23 reflects and enters the polarizing element 24, and is deflected by the second mirror 25 to be collimated by the collimating mirror group 26. It is directly transferred to the surface of the alignment film 14a. This scheme can correct the deviation of the incident angle of the polarized light of the alignment film 14a to some extent by using two mirror compensation methods. However, for large-field polarized light alignment devices, the size of the system mirror and the collimating lens will be large, which greatly increases the processing cost and the difficulty of the system.

The quarter-wave plate 32 is an important optical component that utilizes its phase delay characteristics to achieve polarization conversion of the beam. Figure 3 shows a polarization purification device using a set of waveplate stacks 31, a quarter waveplate 32, a first mirror 33 and a second mirror 34 to effect adjustment of the polarization state of the beam. The polarization direction is consistent with the expected polarization direction, which improves the energy utilization of the optical system. However, the polarized light illumination system modulated by the quarter wave plate 32 still has a problem of poor uniformity of illumination.

The invention provides a polarized light illumination system and a polarized illumination modulation method to solve the above technical problems.

In order to solve the above technical problem, the present invention provides a polarized light illumination system including a microwave electrodeless lamp, a quadric reflector housing, a polarization conversion device, and a wire grid polarizing element, wherein the microwave electrodeless lamp is located in the quadric reflector At the focus of the casing, the polarization conversion device and the wire grid polarizing element are sequentially located directly under the microwave electrodeless lamp.

Preferably, a quartz window protection glass and a filter are sequentially disposed between the microwave electrodeless lamp and the wire grid polarizing element, and the polarization conversion device is disposed on the microwave electrodeless lamp and the quartz window protection glass. Or between the quartz window cover glass and the filter, or between the filter and the wire grid polarizing element.

Preferably, the polarization conversion device uses a quarter wave plate, a half wave plate or a depolarization component.

Preferably, the microwave electrodeless lamp is formed by splicing a plurality of light pipes in a lateral direction and a longitudinal direction.

Preferably, the light output power of each of the light pipes is adjustable.

Preferably, the position of each of the light pipes is adjustable in the lateral direction.

In order to solve the above technical problem, the present invention provides a polarized light illumination modulation method, comprising the steps of: providing a microwave electrodeless lamp at a focus of a quadric reflector housing for emitting an illumination beam and transmitting the quadric reflector housing Reflecting to form a reflected beam; Preferably, a polarization conversion device is provided, and the reflected beam is polarized to form S-polarized light and P-polarized light; preferably, a wire grid polarizing element is disposed to pass the P-polarized light, and the S-polarized light is reflected. .

The S-polarized light is reflected by the polarized light conversion device, reflected by the quadric reflector, and transmitted through the polarized light conversion device to be partially converted into P-polarized light and transmitted through the wire grid polarized light. element.

Compared with the prior art, the present invention provides a polarized light illumination system and a polarized light illumination modulation method, and the polarized light illumination system includes a microwave electrodeless lamp, a quadric reflector housing, a polarization conversion device, and a wire grid polarizing element. The microwave electrodeless lamp is located at a focus of the quadric reflector, and the polarization conversion device and the wire grid polarizing element are sequentially located directly below the microwave electrodeless lamp. The invention adopts the microwave electrodeless lamp splicing to realize the polarized light irradiation field of view of the large field of view, and improves the static uniformity and integral uniformity of the illumination system by utilizing the adjustability of the microwave-free electrodeless lamp; and the polarized light conversion device is used to illuminate the polarized light. The system's light polarization direction is modulated to improve energy utilization, thereby achieving large field of view, high illumination polarized illumination.

11‧‧‧ rod light source

12‧‧‧ Quadric Reflective Shell

13‧‧‧Wire grid polarized polarizer

14‧‧‧Workpiece

14a‧‧‧Alignment film

15‧‧‧ substrate table

21‧‧‧bubble high pressure mercury lamp

22‧‧‧Spherical spherical reflector shell

23‧‧‧First mirror

24‧‧‧Polarized elements

25‧‧‧second mirror

26‧‧‧ collimating mirror

31‧‧‧Wavestock pile

32‧‧‧ Quarter Wave Plate

33‧‧‧First mirror

34‧‧‧second mirror

100‧‧‧Microwave Induction Lamp

200‧‧‧ quadric reflector housing

300‧‧‧Polarized light conversion device

400‧‧‧Wire grid polarizing element

500‧‧‧Quartz window protection glass

600‧‧‧Filter

Figure 1 is a schematic view showing the structure of a conventional optical alignment device.

FIG. 2 is a schematic structural view of a conventional polarized light illumination device.

Fig. 3 is a schematic view showing the structure of a conventional polarization purification apparatus.

FIG. 4 is a schematic structural view of a polarized light illumination system according to an embodiment of the present invention.

Figure 5 is a schematic diagram showing the polarization state of a quarter-wave plate modulated polarized beam in an embodiment of the present invention.

FIG. 6 is a schematic diagram of a splicing field of view of a plurality of lamps in an embodiment of the present invention.

FIG. 7 is a schematic diagram showing the uniformity of relative motion compensation integral of a plurality of rows of lamps in an embodiment of the present invention.

Figure 8 is a graph showing the uniformity adjustment curve of a polarized light illumination system in accordance with an embodiment of the present invention.

The above described objects, features and advantages of the present invention will become more apparent from the aspects of the appended claims. It should be noted that the present invention is in a simplified form and uses a non-precise ratio, which is only for convenience and clarity to assist the purpose of the embodiments of the present invention.

The polarized light illumination system provided by the present invention, as shown in FIGS. 4 and 5, includes a microwave electrodeless lamp 100, a quadric reflector housing 200, a polarization conversion device 300, and a wire grid polarizing element 400, and the microwave electrodeless lamp 100 is located at two. At the focus of the secondary curved reflector 200, the polarization conversion device 300 and the wire grid polarizing element 400 are sequentially located directly below the microwave electrodeless lamp 100. Specifically, in the present embodiment, the light emitted by the microwave electrodeless lamp 100 is concentrated by the quadric reflector housing 200 and concentrated under the quadric reflector housing 200. After the polarization conversion device 300 is changed, the wire grid polarizing element is changed. The polarization state of the reflected light of 400 causes the S-polarized light reflected by the wire grid polarizing element 400 to be partially converted into the P-polarized light transmitting wire grid polarizing element 400 by the double action of the quadric reflector 200 and the polarization conversion device 300. , thereby improving the polarized light illumination system The energy utilization efficiency; on the other hand, the use of the adjustable intensity of the microwave electrodeless lamp 100 to improve the static uniformity and integral uniformity of the illumination system.

Referring to FIG. 5, the S-polarized light reflected by the wire grid polarizing element 400 is converted into elliptically polarized light containing S and P polarized light through the polarization conversion device 300, and the elliptically polarized light passes through the quadric reflective cover 200. The reflected elliptically polarized light is still elliptically polarized light after passing through the polarization conversion device 300, and the elliptically polarized light with the P-polarized light component passes through the P-polarized light component of the line-gate polarizing element 400, thereby improving the polarization illumination. The energy utilization of the system. After preliminary simulation analysis, the polarized light conversion device 300 is used to correct the polarization direction, and the total light output of the system is 13% higher than that of the non-polarization conversion device 300.

Preferably, referring to FIG. 4, a quartz window protection glass 500 and a filter 600 are sequentially disposed between the microwave electrodeless lamp 100 and the wire grid polarizing element 400, and the polarization conversion device 300 is disposed on the microwave electrodeless lamp 100 and the quartz window. Between the protective glass 500, or between the quartz window protection glass 500 and the filter 600, or between the filter 600 and the wire grid polarizing element 400, specifically, the quartz window protection glass 500 is used to achieve pollution in the optical path. The object is rejected; the filter 600 is used to filter out the illumination light of the required band.

Preferably, the polarization conversion device 300 can use a quarter wave plate, a half wave plate or a depolarization component, and can change the polarization state of the light reflected by the wire grid polarizing element 400.

Preferably, referring to Figures 6 and 7, the microwave electrodeless lamp 100 is formed by splicing a plurality of light pipes in the horizontal direction and the longitudinal direction. Specifically, the illumination field of view of the plurality of small light pipes is spliced to achieve large illumination. Field of view.

Preferably, the light output power of each light pipe is adjustable. When the local light intensity of the illumination field is strong or weak, the illumination adjustment of the area can be adjusted by adjusting the working power of the single light pipe, thereby adjusting the static uniformity of the illumination system from 15% to 7% of the single light pipe.

Preferably, please refer to FIG. 7 in detail, the position of each light pipe is adjustable in the lateral direction, that is, when a single row of light pipes (ie, a plurality of light pipes arranged in the lateral direction in FIG. 7) When the integral uniformity is locally high or low, the integral uniformity adjustment can be realized by moving the relative position of the light pipe in the lateral direction. As shown in Fig. 8, the scanning integral uniformity of the system can be controlled within 3% by moving the relative positions of the light pipes in a row in the lateral direction.

The invention further provides a polarized light illumination modulation method, comprising the following steps:

Step 1. The microwave electrodeless lamp 100 is disposed at a focus of the quadric reflector housing 200 for emitting an illumination beam and reflecting through the quadric reflector housing 200 to form a reflected beam;

Step 2, setting a polarization conversion device 300, performing polarization modulation on the reflected beam to form S-polarized light and P-polarized light;

Step 3. The wire grid polarizing element 400 is provided to pass the P-polarized light and the S-polarized light is reflected.

In step 4, the S-polarized light is reflected by the polarization conversion device 300, reflected by the quadric reflector 200, transmitted through the polarization conversion device 300, and partially converted into P-polarized light transmitted through the wire grid polarizing element 400.

In summary, the present invention provides a polarized light illumination system and a polarized light illumination modulation method. The polarized light illumination system includes a microwave electrodeless lamp 100, a quadric reflector housing 200, a polarization conversion device 300, and a wire grid polarizing element 400. The lamp 100 is located at the focus of the quadric reflector housing 200, and the polarization conversion device 300 and the wire grid polarizing element 400 are sequentially located directly below the microwave electrodeless lamp 100. The invention adopts the microwave electrodeless lamp 100 splicing to realize the polarized light irradiation field of view of the large field of view, and improves the static uniformity and integral uniformity of the illumination system by utilizing the adjustability of the light intensity of the microwaveless electrodeless lamp 100; and simultaneously adopts the polarization conversion device 300. The polarization direction of the polarized light illumination system is modulated to improve the energy utilization rate, thereby realizing large field of view and high illumination polarized illumination.

It will be apparent to those skilled in the art that various modifications and variations can be made in the invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of the invention as claimed.

Claims (6)

A polarized light illumination system for use in an optical alignment device, comprising: a microwave electrodeless lamp; a quadric reflective cover; a polarization conversion device; and a wire grid polarizing element, the microwave electrodeless lamp being located on the quadric surface At the focus of the reflector housing, the polarization conversion device and the wire grid polarizing element are sequentially located directly under the microwave electrodeless lamp; wherein the microwave electrodeless lamp is formed by splicing a plurality of light pipes in a lateral direction and a longitudinal direction. The polarized light illumination system of claim 1, wherein the microwave electrodeless lamp and the wire grid polarizing element are sequentially provided with a quartz window protection glass and a filter, and the polarization conversion device is disposed on the microwave electrodeless Between the lamp and the quartz window protection glass, between the quartz window protection glass and the filter, or between the filter and the wire grid polarizing element. The polarized light illumination system of claim 1 or 2, wherein the polarized light conversion device uses a quarter wave plate, a half wave plate or a depolarization component. The polarized light illumination system of claim 1, wherein the light output power of each of the light pipes is adjustable. The polarized light illumination system of claim 1, wherein the position of each of the light pipes is adjustable in a lateral direction. A polarized light illumination modulation method for optical alignment includes the following steps: Step 1. Set a microwave electrodeless lamp at a focus of a quadric reflector housing for emitting an illumination beam and reflecting through the quadric reflector housing to form a reflected beam, wherein the microwave electrodeless lamp is composed of a plurality of lights The tube is formed by splicing in the horizontal direction and the longitudinal direction; in step 2, a polarization conversion device is disposed, and the reflected beam is polarized to form an S-polarized light and a P-polarized light; and in step 3, a line-gate polarizing element is disposed to make the P The polarized light passes through, and the S-polarized light is reflected. In step 4, the S-polarized light is reflected and passed through the polarized light converting device, reflected by the quadric reflective cover, and partially converted into the polarized light converting device. P-polarized light is transmitted through the wire grid polarizing element.