JP3936086B2

JP3936086B2 - Light irradiation device

Info

Publication number: JP3936086B2
Application number: JP33132698A
Authority: JP
Inventors: 榮錫崔; 純凡權; 秉徳宋; 基赫尹
Original assignee: エルジーフィリップスエルシーディーカンパニーリミテッド
Priority date: 1998-11-06
Filing date: 1998-11-20
Publication date: 2007-06-27
Anticipated expiration: 2018-11-20
Also published as: KR20000031441A; JP2000147506A; KR100323731B1; GB2343525A; DE19953356A1; FR2785687A1; DE19953356B4; GB2343525B; FR2785687B1; TW518427B; GB9926307D0

Abstract

A device for obliquely irradiating a substrate, preferably the alignment layer for a liquid crystal device, comprises a polariser 33, an optical system for supplying light to the polariser and a stage 11 on which the substrate is mounted the arrangement being such that light from the polariser falls on the stage at an angle to the normal. The optical system includes a homogenizer lens 19 located between second and third polarisers 31, 51 and collimating lens 7. The polarisers each comprise a plate, e.g. of laminated quartz, slanted at Brewsters angle.

Description

【０００１】
【発明の属する技術分野】
本発明は光照射装置に関するものであって、特に、液晶表示素子の光配向の工程に用いられる大面積の光照射装置に関する。
【０００２】
【従来の技術】
一般的に、液晶表示素子はスペーサにより、所定の間隔をおいて対向配置された上下基板と、前記上下基板の間に形成された液晶層からなる。上下基板は、それぞれの対向面に所定のパターンの電極を保持しており、これの電極の上部には、液晶の配向を決める配向膜が形成されている。
【０００３】
前記配向膜を処理する配向方法としては、ラビング（rubbing method）或は光配向法（photo-alignment method）などが用いられている。
【０００４】
前記ラビング法は基板にポリイミド（PI,polyimide）などの配向物質を塗布した後、ラビング布で機械的摩擦を引き起こして液晶の配向方向をもたらす方法であって、大面積化と高速処理とが可能となって工業的に広く利用されているものである。
【０００５】
しかしながら、摩擦強度によって配向膜に形成される微細溝の形態が変わるようになって液晶分子の配列が一定ではないという問題点があり、これによる不規則な位相歪曲（random phase distortion）と光散乱（light scattering）とが発生されて、液晶表示素子の性能を低下させるおそれがある。また、ラビング処理の際発生するゴミ及び静電気は、歩留りを減少させる原因となり、画素の分割をしてマルチドメインを具現する場合には、繰り返されるフォトリソグラフィー（photolithography）工程で、配向膜の信頼性と安定性とを具現することに難点を持っている。
【０００６】
一方、前記光配向工程は、光配向膜が塗布された基板上に紫外線を照射して液晶のプリチルトと配向方向をもたらす方法であって、ラビング法と異なって静電気やゴミが発生するおそれがなく、それによる歩留りの減少を助けることができる。また、配向膜の全体にわたって、液晶分子を均一に配列させることができるので、位相歪曲や光散乱という現象が生じることを防止できる。
【０００７】
特に、画素の分割による光視野角の液晶表示素子の具現を実際に可能とする長所がある。
【０００８】
前記のような光配向の工程に用いられる光照射装置が、日本特許公開平10-90684(1998.4.10)及び日本特許公開平10-161126(1998.6.19)で提案されたことがある。
【０００９】
図１は、前記日本特許公開平10-90684に記載された従来の光照射装置の構成を示す概略図であって、前記従来の光照射装置は、液晶表示素子の配向膜に偏光された光を照射するための配向膜の光配向用の偏光の光照射装置に関するものである。
【００１０】
その構成及び作用をみてみると、光源（１）から放射される紫外光を含む光は集光鏡（２）で集光され、第１反射鏡（３）で反射されて、集光レンズ（５）に入射される。シャッター（４）を媒介として、集光レンズ（５）から流れてきた光は第２反射鏡（６）で反射され、視準レンズ（７）で平行光となって、偏光素子（８）に入射される。偏光素子（８）は複数のガラス板（８a）を間隔をおいて平行配置したものであって、前記ガラス板（８a）は入射光に対してブリュースタ角（Brewster angle）を成すように傾斜配置されたものであり、P偏光を透過させたS偏光の大部分を反射する。偏光素子（８）から出射されたP偏光は、マスク（１３）を媒介として基板（３５）に照射される。
【００１１】
前記のように構成された光照射装置では、偏光比（polarization ratio :s/p, s: 垂直偏光、p:水平偏光）を0.1以下に設定したし、偏光方向が一定な偏光光を照射して液晶表示素子の配向膜に光配向を適用でき、既存の他の装置より、透過率、波長の依存性、耐久性、寿命などに優秀である。しかし、大面積の液晶表示素子を製造するためには、前記偏光素子（８）のガラス板（８a）を大きめに製造しなければならなく、さらに効果的な光配向の工程に適用するには、偏光比の範囲が適正ではないという問題がある。
【００１２】
図２は、前記日本特許公開平10-161126に記載された従来の光照射装置の構成を示す概略図であって、その構成及び作用をみてみると、光源（１）と、集光鏡（２）と、視準レンズ（７）と、多眼型レンズ（１９）と、集光レンズ（５）と、前記光源（１）から発生した光を基板（３５）に導く一つ以上の反射鏡（３）（６）を備えた露光装置にて、前記反射鏡の中、少なくとも一つの反射鏡が、第１偏光を主に反射する反射型の回折格子で構成される。
【００１３】
第１反射鏡（３）は、一般的に第２反射鏡（６）より小面積であるので、前記第１反射鏡（３）を所定の回折格子で構成した場合、小面積の回折格子にできる利点がある。この際、所定の回折格子が多眼型レンズ（１９）の前に位置するので、前記回折格子が多眼型レンズの出力光に影響を及ぼすことが防止できる。
【００１４】
前記のように構成することによって、前記光照射装置は、第１偏光を主に反射する反射型の回折格子による反射光を照射することによって、偏光された光を大面積に一括に照射できる。
【００１５】
しかしながら、前記光照射装置における回折格子は、その偏光の特性が波長の依存性が大きい。
【００１６】
前記従来の技術等は、偏光された光を具現するため既存の光照射装置に偏光手段を追加することのみに焦点が合っているので、実際の光配向工程には、不適宜であるという問題点がある。
【００１７】
【発明が解決しようとする課題】
本発明は前記従来技術の問題点を鑑みてなされたものであって、大面積の照射が可能であり、光を傾斜照射して配向膜の配向方向及びプリチルト角を決める光照射装置を提供することを目的とする。
【００１８】
【課題を解決するための手段】
前記目的を達成するため、本発明による光照射装置は、光学系と、前記光学系からの光を偏光させる第１偏光子と、前記第１偏光子から出た光が、基板が置かれてあるステージの法線に対して、所定の角度（θ）に傾斜されるように照射される。
【００１９】
前記光学系は、光源とレンズと反射鏡とで構成され、反射鏡は一つ以上で構成されることができる。また、前記レンズと反射鏡との間に第２偏光子が構成されることができるし、必要によって第３偏光子も構成されることができる。
【００２０】
前記目的を達成するため、本発明による光照射装置は、光源と、前記光源からの光を反射する第１反射鏡と、複数のレンズからなった多眼型レンズと、前記多眼型レンズからの光を反射する第２反射鏡と、前記第２反射鏡からの光を平行光となるようにする視準レンズと、そして前記視準レンズからの光を偏光させる第１偏光子と、前記第１偏光子から流れてくる光が基板の置かれるステージの法線に対して、所定の角度（θ）に傾斜されるように照射される。
【００２１】
前記光照射装置は、前記第１反射鏡と多眼型レンズの間に第２偏光子を追加に含むか、前記多眼型レンズと第２反射鏡の間に第３偏光子を追加に含む。
【００２２】
前記第１偏光子は、200nm〜800nmの波長の光に対して、透過率が高いものがよく、好ましくは250nm〜400nmの波長で、透過率が高いものがよい。
【００２３】
前記第１偏光子は、0〜１の偏光度を有し、好ましくは0.2〜0.95の偏光度を有する。
【００２４】
前記角度（θ）は、0°〜45°の範囲内にあるのが好ましい。
【００２５】
【発明の実施の形態】
以下、図面を参照して本発明による光照射装置を詳細に説明する。
【００２６】
図３及び図４は、本発明の光照射装置のyz及びxz側面図である。
【００２７】
本発明の光照射装置は、光源（１）と、集光鏡（２）と、第１反射鏡（３）、レンズ（３７）と、多眼型レンズ（１９）と、第２反射鏡（６）と、視準レンズ（collimator lens）（７）と、マスク（１３）と、基板（３５）が置かれるステージ（１１）と、そして偏光子で構成される。
【００２８】
前記集光鏡（２）は、光源（１）からの光を第１反射鏡（３）に向けるように調節し、多眼型レンズ（homogenizer ; fly eye lens）（１９）は複数のレンズからなっており、前記レンズのそれぞれを通過した光が重ねるように光を屈折させる。第２反射鏡（６）は、前記多眼型レンズ（１９）から流れてきた光を反射し、視準レンズ（７）は、前記第２反射鏡（６）で反射された光を平行光として、基板（３５）上に形成された配向膜（２５）へ導く。前記視準レンズ（７）はミラー（mirror）或はレンズが可能であり、前記多眼型レンズは、凸型或は凹型の中いずれも可能である。
【００２９】
本発明の光照射装置では、偏光子を第１偏光子（３３）の位置に構成し、必要によって前記多眼型レンズの前（第２偏光子（３１）の位置）及び／或は後（図に示さない）の位置に、少なくとも一つ以上が構成できる。
【００３０】
前記偏光子は積層された石英基板、積層されたガラス基板、或はマルチ−コーティングされた基板などからなり、耐熱性と耐久性とがよく、波長の依存性が少ないものが好ましい。積層された石英基板或はガラス基板は、基板に対してブリュースタ角（brewster angle, θ＝tan^-1n,n :石英或はガラスの屈折率）に傾斜されたものを用いる。従って、ブリュースタ角は57〜60°程度の範囲となる。積層された石英或はガラス基板を、大面積の照射の際均一に光が照射でき、マルチ−コーティングされた基板は、基板上に無機膜がコーティングされたものを用い、無機膜は主にSiO₂である。
【００３１】
また、前記偏光子は、200nm〜800nmの波長の範囲の透過率が高いものがよく、250nm〜400nmの波長の範囲の透過率が高いものが好ましい。
【００３２】

は、0∠PD∠1の範囲の部分偏光（partiallypolarized）となるものがよく、0.2∠PD∠0.95の範囲のものが好ましい。そして、配向膜（２５）の種類によって適当な値の偏光度を選ぶことができる。
【００３３】
図４に示したように、前記光照射装置をxz側から見ると、光学系（１００）から照射される光は、光の傾斜露光のため基板の法線に対して、一定の角度に傾けられており、光照射装置での最大の透過軸の方向は、図でのように定義された光経路の平面（xz）に垂直であったり、平行である。従って、前記のように構成することによって、配向膜（２５）の部分偏光された光を傾斜照射することができる。
【００３４】
図５は本発明の光照射装置で、配向膜のプリチルト角の制御を示すxz側面図である。配向膜（２５）上で液晶分子（２７）のプリチルト角（θp）は、前記配向膜（２５）に照射される光のエネルギーの量や配向膜の物質と、それによる光照射装置の偏光度により調節される。それに反して、前記液晶分子（２７）の配向方向は、前記傾斜露光の際の光照射の方向によって決められる。
【００３５】
この際、使用可能な光照射の角度（θ）は、0°〜45°の範囲内にあるのが好ましく、仮に、前記光照射の角度（θ）が４５°以上であれば、マスク（１３）と配向膜（２５）との間のギャップ（gap）の誤差による効果が極大化されるので、マスクのパターンによる配向膜上のパターン位置の誤差が大きくなる。
【００３６】
次の表は、マスクと配向膜との間のギャップ（gap）誤差が、20μmである場合、光照射の角度（θ）によるパターン位置の誤差を示す。
【００３７】
【表１】

【００３８】
図６,７及び８は、本発明の光照射装置にて、配向膜の配向方向の制御を示す第１、第２及び第３実施例のxy側面図であり、図で厚い実線の矢印は、基板の配向方向を示す。そして、実線の四角形は、基板の第１位置（４５）を、一点鎖線の四角形は、基板の第２位置（４７）をそれぞれ示す。
【００３９】
上記したように、本発明の装置では、傾斜露光の際の光照射の方向によって、配向方向が決められるので、光配向の工程で基板上の光照射の方向、即ち、光の方位角（azimuthangle）が重要である。この光の方位角を調節する方法は、図６,７及び８に示している。
【００４０】
図６の第１実施例のように、モノドメイン（mono-domain）或はマルチドメイン（multi-domain）の液晶表示素子を製造するにおいて、配向方向を基板の長軸方向に対して、０°或は９０°（４５°或は１３５°）に形成する場合、基板を９０°回転させればよいので、光学系（１００）は基板の長軸方向に対して、０°或は４５°の方向に位置するように配置される。
【００４１】
即ち、前記配向方向を含んだ任意の配向方向を形成しようとする際には、図７の第２実施例と図８の第３実施例のように配置するのがよく、好ましくは図８に示した実施例がよい。図７では、基板が置かれたステージ（１１）を、所定の角度（φ）に回転させることによって、必要な配向方向が容易に形成できる。しかし、前記配置ではマルチドメインの液晶表示素子を製造する場合、マスクを一緒に回転すべきであるので、マスクと基板の間のギャップの保持が必要となる。図８では、光学系（１００）を所定の角度（φ）に移動させることによって、第１配向方向及び光学系の移動による第２配向方向を形成して液晶セルの領域中の偏光方向が、二つ以上が混在するマルチドメインが具現できる。
【００４２】
図９は、本発明の光照射装置にて配向膜の露光領域を示すxz側面図である。
【００４３】
マルチドメインの液晶表示素子を製造するためマスクを用いる際には、マスク（１３）と基板（３５）上の配向膜（２５）との間に、一定のギャップ（ｄ）を保持しなければならなく、前記ギャップは30μm〜100μmが好ましい。
【００４４】
前記図でのように、所定の光照射の角度（θ）に入射される光が、マスク（１３）を通過して配向膜（２５）に照射されると、露光される領域は前記光照射の角度に対して、Δx(Δx＝dtanθ)ほどが移動されるので、マスク（１３）のパターン或は前記数値ほど移動して形成される。
【００４５】
従って、実質的な光配向の工程では、マスク（１３）と基板（３５）との間に、一定のギャップを正確に測定し、測定されたギャップと光照射の角度を考えて基板を初期の整列状態から移動させ、光照射することが必須的である。
【００４６】
前記のようにするためには、前記過程中で、ギャップ測定用の装置が必要であり、レーザーなどの測定用の補助光源を用いてギャップを測定する。この際、ギャップの測定位置は、３〜４の位置を選定してギャップを測定し、測定位置の間のギャップの誤差を縮めるため微細な位置別のギャップの補正装置をステージ（１１）の下段に設けて、光配向の工程をより精密に遂行する。
【００４７】
【発明の効果】
本発明の光照射装置は、偏光子を光照射される基板に対して、所定の角度に傾斜されるように配置して部分偏光された光を傾斜照射することによって、配向膜の配向方向及びプリチルト角を、一回の照射に決めることができる。
【００４８】
また、マルチドメインの液晶表示素子を製造するためマスクと基板とのギャップを精密に測定し、配向膜上に均一なパターンを形成すことによって、大面積及びマルチドメインの液晶表示素子を効果的に具現できる。
【図面の簡単な説明】
【図１】図１は、従来の光照射装置の概略図。
【図２】図２は、従来の他の光照射装置の概略図。
【図３】図３は、本発明の光照射装置のyz側面図。
【図４】図４は、本発明の光照射装置のxz側面図。
【図５】図５は、本発明の光照射装置にて配向膜のプリチルト角の制御を示すxz側面図。
【図６】図６は、本発明の光照射装置にて配向膜の配向方向の制御を示す第１、第２及び第３実施例のxy側面図。
【図７】図７は、本発明の光照射装置にて配向膜の配向方向の制御を示す第１、第２及び第３実施例のxy側面図。
【図８】図８は、本発明の光照射装置にて配向膜の配向方向の制御を示す第１、第２及び第３実施例のxy側面図。
【図９】図９は、本発明の光照射装置にて配向膜の露光領域を示すxz側面図。
【符号の説明】
１光源
２集光鏡
３第１反射鏡
４シャッター（shutter）
５集光レンズ
６第２反射鏡
７視準レンズ（collimator lens）
８偏光素子
８a ガラス板
１０配向顕微鏡
１１ステージ
１３マスク
１９多眼型レンズ（homogenizer）
２５配向膜
２７液晶分子
３１第２偏光子
３３第１偏光子
３５基板
３７レンズ
４１第１配向方向
４３第２配向方向
４５基板の第１位置
４７基板の第２位置
１００光学系[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light irradiation apparatus, and more particularly to a large area light irradiation apparatus used in a photo-alignment process of a liquid crystal display element.
[0002]
[Prior art]
In general, a liquid crystal display element includes a vertical substrate and a liquid crystal layer formed between the upper and lower substrates, which are opposed to each other at a predetermined interval by a spacer. The upper and lower substrates hold electrodes of a predetermined pattern on their opposing surfaces, and an alignment film that determines the alignment of the liquid crystal is formed on the electrodes.
[0003]
As an alignment method for treating the alignment film, rubbing method or photo-alignment method is used.
[0004]
The rubbing method is a method in which an alignment material such as polyimide (PI) is applied to a substrate, and then mechanical rubbing is caused by a rubbing cloth to bring the alignment direction of the liquid crystal. Large area and high speed processing are possible. It is widely used industrially.
[0005]
However, there is a problem that the alignment of the liquid crystal molecules is not constant because the shape of the micro-grooves formed in the alignment film changes depending on the friction strength, and this causes random phase distortion and light scattering. (Light scattering) may be generated and the performance of the liquid crystal display element may be degraded. In addition, dust and static electricity generated during the rubbing process cause a decrease in yield, and in the case of implementing a multi-domain by dividing a pixel, the reliability of the alignment film is repeated in a repeated photolithography process. And have a difficulty in realizing stability.
[0006]
On the other hand, the photo-alignment step is a method of irradiating a substrate coated with a photo-alignment film with ultraviolet rays to bring about a pretilt and alignment direction of liquid crystal, and unlike the rubbing method, there is no possibility of generating static electricity or dust. , Can help reduce the yield. In addition, since liquid crystal molecules can be uniformly arranged over the entire alignment film, the phenomenon of phase distortion and light scattering can be prevented.
[0007]
In particular, there is an advantage that a liquid crystal display element having a light viewing angle by dividing pixels can be actually realized.
[0008]
A light irradiation apparatus used in the above-described photo-alignment process has been proposed in Japanese Patent Publication No. 10-90684 (1998.4.10) and Japanese Patent Publication No. 10-161126 (1998.6.19).
[0009]
FIG. 1 is a schematic view showing a configuration of a conventional light irradiation apparatus described in the Japanese Patent Publication No. Hei 10-90684. The conventional light irradiation apparatus is a light beam polarized on an alignment film of a liquid crystal display element. The present invention relates to a polarized light irradiating apparatus for photo-alignment of an alignment film.
[0010]
Looking at its configuration and operation, light including ultraviolet light emitted from the light source (1) is collected by the collecting mirror (2), reflected by the first reflecting mirror (3), and collected by the collecting lens ( 5). The light flowing from the condenser lens (5) through the shutter (4) is reflected by the second reflecting mirror (6), becomes parallel light by the collimating lens (7), and enters the polarizing element (8). Incident. The polarizing element (8) has a plurality of glass plates (8a) arranged in parallel at intervals, 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 been transmitted through the P-polarized light. The P-polarized light emitted from the polarizing element (8) is applied to the substrate (35) through the mask (13).
[0011]
In the light irradiation device configured as described above, the polarization ratio (s / p, s: vertical polarization, p: horizontal polarization) is set to 0.1 or less, and polarized light having a constant polarization direction is irradiated. Thus, photo-alignment can be applied to the alignment film of the liquid crystal display element, which is superior to other existing devices in terms of transmittance, wavelength dependency, durability, and lifetime. However, in order to manufacture a liquid crystal display element with a large area, the glass plate (8a) of the polarizing element (8) must be manufactured to be large, and it can be applied to a more effective photo-alignment process. There is a problem that the range of the polarization ratio is not appropriate.
[0012]
FIG. 2 is a schematic view showing a configuration of a conventional light irradiation apparatus described in Japanese Patent Publication No. Hei 10-161126. Looking at the configuration and operation thereof, a light source (1), a condensing mirror ( 2), a collimating lens (7), a multi-lens lens (19), a condenser lens (5), and one or more reflections that guide the light generated from the light source (1) to the substrate (35). In the exposure apparatus including the mirrors (3) and (6), at least one of the reflecting mirrors is formed of a reflective diffraction grating that mainly reflects the first polarized light.
[0013]
Since the first reflecting mirror (3) is generally smaller in area than the second reflecting mirror (6), when the first reflecting mirror (3) is constituted by a predetermined diffraction grating, the first reflecting mirror (3) is a small-area diffraction grating. There are advantages you can do. At this time, since the predetermined diffraction grating is positioned in front of the multi-lens lens (19), it is possible to prevent the diffraction grating from affecting the output light of the multi-lens lens.
[0014]
By configuring as described above, the light irradiation device can irradiate polarized light in a large area in a lump by irradiating the reflected light from a reflective diffraction grating that mainly reflects the first polarized light.
[0015]
However, the diffraction grating in the light irradiating apparatus has a large wavelength dependence of the polarization characteristics.
[0016]
Since the conventional techniques are focused only on adding a polarizing means to an existing light irradiation device in order to realize polarized light, there is a problem that it is not appropriate for an actual light alignment process. There is a point.
[0017]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned problems of the prior art, and provides a light irradiation apparatus that can irradiate a large area and determines the alignment direction and pretilt angle of the alignment film by irradiating light with an inclination. For the purpose.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, a light irradiation apparatus according to the present invention includes an optical system, a first polarizer that polarizes light from the optical system, and a light that is emitted from the first polarizer. Irradiation is performed so as to be inclined at a predetermined angle (θ) with respect to a normal line of a certain stage.
[0019]
The optical system may include a light source, a lens, and a reflecting mirror, and the reflecting mirror may include one or more. In addition, a second polarizer can be configured between the lens and the reflecting mirror, and a third polarizer can be configured if necessary.
[0020]
To achieve the above object, a light irradiation apparatus according to the present invention includes a light source, a first reflecting mirror that reflects light from the light source, a multi-lens lens including a plurality of lenses, and the multi-lens lens. A second reflecting mirror that reflects the light from the second reflecting mirror, a collimating lens that makes the light from the second reflecting mirror become parallel light, a first polarizer that polarizes the light from the collimating lens, Light flowing from the first polarizer is irradiated so as to be inclined at a predetermined angle (θ) with respect to the normal line of the stage on which the substrate is placed.
[0021]
The light irradiation device additionally includes a second polarizer between the first reflecting mirror and the multi-lens lens, or additionally includes a third polarizer between the multi-lens lens and the second reflecting mirror. .
[0022]
The first polarizer preferably has a high transmittance with respect to light having a wavelength of 200 nm to 800 nm, and preferably has a wavelength of 250 nm to 400 nm and a high transmittance.
[0023]
The first polarizer has a degree of polarization of 0 to 1, and preferably has a degree of polarization of 0.2 to 0.95.
[0024]
The angle (θ) is preferably in the range of 0 ° to 45 °.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a light irradiation apparatus according to the present invention will be described in detail with reference to the drawings.
[0026]
3 and 4 are side views of yz and xz of the light irradiation apparatus of the present invention.
[0027]
The light irradiation device of the present invention includes a light source (1), a condenser mirror (2), a first reflecting mirror (3), a lens (37), a multi-lens lens (19), and a second reflecting mirror ( 6), a collimator lens (7), a mask (13), a stage (11) on which a substrate (35) is placed, and a polarizer.
[0028]
The condensing mirror (2) adjusts the light from the light source (1) so as to be directed to the first reflecting mirror (3), and the homogenizer (fly eye lens) (19) is composed of a plurality of lenses. The light is refracted so that the light passing through each of the lenses overlaps. The second reflecting mirror (6) reflects the light flowing from the multi-lens lens (19), and the collimating lens (7) collimates the light reflected by the second reflecting mirror (6). To the alignment film (25) formed on the substrate (35). The collimating lens (7) can be a mirror or a lens, and the multi-lens lens can be either a convex type or a concave type.
[0029]
In the light irradiation device of the present invention, the polarizer is configured at the position of the first polarizer (33), and if necessary, before the multi-lens lens (position of the second polarizer (31)) and / or after ( At least one or more can be configured at positions (not shown).
[0030]
The polarizer is preferably made of a laminated quartz substrate, a laminated glass substrate, a multi-coated substrate, or the like, which has good heat resistance and durability and has little wavelength dependency. As the laminated quartz substrate or glass substrate, a substrate tilted at a Brewster angle (brewster angle, θ = tan ⁻¹ n, n: quartz or glass refractive index) is used. Accordingly, the Brewster angle is in the range of about 57-60 °. A laminated quartz or glass substrate can be irradiated with light uniformly when irradiating a large area. A multi-coated substrate uses a substrate coated with an inorganic film, and the inorganic film is mainly made of SiO. ₂ .
[0031]
The polarizer preferably has a high transmittance in the wavelength range of 200 nm to 800 nm, and preferably has a high transmittance in the wavelength range of 250 nm to 400 nm.
[0032]

Is preferably partially polarized in the range of 0∠PD∠1, and preferably in the range of 0.2∠PD∠0.95. A suitable degree of polarization can be selected depending on the type of the alignment film (25).
[0033]
As shown in FIG. 4, when the light irradiation device is viewed from the xz side, the light irradiated from the optical system (100) is tilted at a certain angle with respect to the normal of the substrate for the tilt exposure of light. The direction of the maximum transmission axis in the light irradiation device is perpendicular to or parallel to the plane (xz) of the optical path defined as shown in the figure. Therefore, by configuring as described above, the partially polarized light of the alignment film (25) can be obliquely irradiated.
[0034]
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. The pretilt angle (θp) of the liquid crystal molecules (27) on the alignment film (25) is determined by the amount of light energy applied to the alignment film (25), the material of the alignment film, and the degree of polarization of the light irradiation device thereby. Adjusted by. On the other hand, the alignment direction of the liquid crystal molecules (27) is determined by the direction of light irradiation in the tilt exposure.
[0035]
At this time, the usable light irradiation angle (θ) is preferably in the range of 0 ° to 45 °. If the light irradiation angle (θ) is 45 ° or more, the mask (13 ) And the alignment film (25), the effect due to the gap error is maximized, and the pattern position error on the alignment film due to the mask pattern increases.
[0036]
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]

[0038]
FIGS. 6, 7 and 8 are xy side views 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. , Shows the orientation direction of the substrate. The solid rectangle indicates the first position (45) of the substrate, and the alternate long and short dash line indicates the second position (47) of the substrate.
[0039]
As described above, in the apparatus of the present invention, since the alignment direction is determined by the direction of light irradiation at the time of tilt exposure, the direction of light irradiation on the substrate in the photo-alignment step, that is, the azimuth angle of light (azimuthangle) )is important. A method for adjusting the azimuth angle of the light is shown in FIGS.
[0040]
As in the first embodiment of FIG. 6, in manufacturing a mono-domain or multi-domain liquid crystal display device, the orientation direction is 0 ° with respect to the major axis direction of the substrate. Alternatively, when forming at 90 ° (45 ° or 135 °), the substrate may be rotated by 90 °, so that the optical system (100) is at 0 ° or 45 ° with respect to the major axis direction of the substrate. It is arranged to be located in the direction.
[0041]
That is, when an arbitrary alignment direction including the alignment direction is to be formed, the alignment is preferably performed as in the second embodiment of FIG. 7 and the third embodiment of FIG. 8, and preferably in FIG. The embodiment shown is good. In FIG. 7, the necessary 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 a multi-domain liquid crystal display device is manufactured, the mask should be rotated together, so that it is necessary to maintain a gap between the mask and the substrate. In FIG. 8, by moving the optical system (100) to a predetermined angle (φ), the first alignment direction and the second alignment direction by movement of the optical system are formed, and the polarization direction in the region of the liquid crystal cell is A multi-domain in which two or more are mixed can be implemented.
[0042]
FIG. 9 is an xz side view showing an exposure region of the alignment film in the light irradiation apparatus of the present invention.
[0043]
When a mask is used to manufacture a multi-domain liquid crystal display element, a certain gap (d) must be maintained between the mask (13) and the alignment film (25) on the substrate (35). The gap is preferably 30 μm to 100 μm.
[0044]
As shown in the figure, when light incident at a predetermined light irradiation angle (θ) passes through the mask (13) and is irradiated onto the alignment film (25), the exposed region is the light irradiation. Since Δx (Δx = dtan θ) is moved with respect to the angle, the pattern of the mask (13) or the numerical value is moved.
[0045]
Accordingly, in the substantial photo-alignment step, a certain gap is accurately measured between the mask (13) and the substrate (35), and the initial position of the substrate is determined in consideration of the measured gap and the angle of light irradiation. It is essential to move from the aligned state and irradiate with light.
[0046]
In order to make it as described above, an apparatus for measuring the gap is necessary in the 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, the gap is measured, and a fine gap correction device for each position is provided at the lower stage of the stage (11) in order to reduce the gap error between the measurement positions. To perform the photo-alignment process more precisely.
[0047]
【The invention's effect】
The light irradiation apparatus of the present invention is configured to irradiate a partially polarized light with a polarizer disposed at a predetermined angle with respect to a substrate to be irradiated with light. The pretilt angle can be determined for a single irradiation.
[0048]
In addition, in order to manufacture a multi-domain liquid crystal display element, the gap between the mask and the substrate is precisely measured, and a uniform pattern is formed on the alignment film. Can be implemented.
[Brief description of the drawings]
FIG. 1 is a schematic view of a conventional light irradiation apparatus.
FIG. 2 is a schematic view of another conventional light irradiation apparatus.
FIG. 3 is a yz side view of the light irradiation apparatus of the present invention.
FIG. 4 is an xz side view of the light irradiation apparatus 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 apparatus of the present invention.
FIG. 6 is an xy side view of first, second and third embodiments showing control of the alignment direction of the alignment film in the light irradiation apparatus of the present invention.
FIG. 7 is an xy side view of first, second and third embodiments showing 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 first, second and third embodiments showing control of the alignment direction of the alignment film in the light irradiation apparatus of the present invention.
FIG. 9 is an xz side view showing an exposure region of an alignment film in the light irradiation apparatus of the present invention.
[Explanation of symbols]
1 Light source 2 Condensing mirror 3 First reflecting mirror 4 Shutter
5 Condenser lens 6 Second reflector 7 Collimator lens
8 Polarizing element 8a Glass plate 10 Orientation microscope 11 Stage 13 Mask 19 Multi-lens 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 47 of substrate second position 100 of substrate optical system

Claims

An optical system including a light source, a lens, and a reflector;
A first polarizer that polarizes light from the optical system and irradiates the polarized film on an alignment film coated on a substrate;
A second polarizer disposed in the optical system;
A stage on which the substrate coated with an alignment film is placed,
The first polarizer is a substrate coated with an inorganic film and is disposed perpendicular to the incident light from the optical system, and the light emitted from the first polarizer is in relation to the normal of the stage. A light irradiation apparatus for forming an alignment film of a liquid crystal display element, wherein the irradiation is performed so as to incline at a predetermined angle (θ).

2. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 1, wherein the reflecting mirror is composed of one or more.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element 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.

4. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 3, wherein the laminated glass substrate and the laminated quartz substrate are laminated while being inclined at a Brewster angle with respect to the substrate.

4. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 3, wherein the multi-coated substrate is coated with an inorganic film.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 1, 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.

2. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 1, wherein the glass substrate on which the second polarizer is laminated and the quartz substrate on which the second polarizer is laminated are inclined at a Brewster angle with respect to the substrate. .

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 1, wherein the multi-coated substrate is coated with an inorganic film.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 1, wherein the first polarizer transmits light having a wavelength of 200 nm to 800 nm.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 9, wherein the first polarizer transmits light having a wavelength of 250 nm to 400 nm.

The light irradiation apparatus for forming an alignment film for a liquid crystal display element according to claim 1, wherein the first polarizer has a polarization degree of 0 to 1. 5.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 1, wherein the first polarizer has a polarization degree of 0.2 to 0.95.

The light irradiation apparatus for forming an alignment film for a liquid crystal display element according to claim 1, wherein the angle (θ) is 0 to 45 °.

The light irradiation apparatus for forming an alignment film for a liquid crystal display element according to claim 1, wherein the stage rotates.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 1, wherein the optical system rotates.

The light irradiation apparatus for forming an alignment film of a liquid crystal display device according to claim 1, wherein a multi-domain is realized by additionally including a mask on the substrate.

17. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 16, wherein a constant gap is maintained between the mask and the substrate.

A light source;
A first reflecting mirror that reflects light from the light source;
A multi-lens lens composed of a plurality of lenses;
A second reflecting mirror that reflects light from the multi-lens lens;
A collimating lens for making the light from the second reflecting mirror a parallel light;
A first polarizer that polarizes light from the collimating lens and irradiates the polarized film on an alignment film coated on a substrate;
A second polarizer disposed between the first reflecting mirror and the multi-lens lens;
A stage on which the substrate coated with an alignment film is placed,
Wherein the first polarizer, the inorganic film is a multi-coated substrates are arranged perpendicularly to incident light from the collimating lens, the first light emitted from the polarizer, the normal line of the stage A light irradiation apparatus for forming an alignment film of a liquid crystal display element, wherein the light is irradiated so as to be inclined at a predetermined angle (θ).

19. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 18, further comprising a third polarizer between the multi-lens lens and the second reflecting mirror.

19. The light irradiation device for forming an alignment film of a liquid crystal display element according to claim 18, wherein the first polarizer partially polarizes light from the collimating lens.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 18, wherein the first polarizer transmits light having a wavelength of 200 nm to 400 nm.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 21, wherein the first polarizer transmits light having a wavelength of 250 nm to 400 nm.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 18, wherein the first polarizer has a polarization degree of 0 to 1.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 23, wherein the first polarizer has a polarization degree of 0.2 to 0.95.

The light irradiation apparatus for forming an alignment film for a liquid crystal display element according to claim 18, wherein the angle (θ) is in the range of 0 to 45 °.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 18, wherein the stage rotates.

19. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 18, wherein the optical system rotates.

19. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 18, wherein a multi-domain is realized by additionally including a mask on the substrate.

29. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 28, wherein a constant gap is maintained between the mask and the substrate.

30. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 29, further comprising a gap measuring apparatus for measuring the gap.

30. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 29, further comprising a gap correction apparatus for correcting the gap.

19. The light irradiation device for forming an alignment film of a liquid crystal display element according to claim 18, wherein the light polarizer is 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.

33. The light irradiation apparatus for forming an alignment film for a liquid crystal display element according to claim 32, wherein the laminated quartz or glass substrate is inclined at a Brewster angle with respect to the substrate.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 32, wherein the multi-coated substrate is coated with an inorganic film.

19. The light irradiation device for forming an alignment film of a liquid crystal display element according to claim 18, wherein the light polarizer is 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.

36. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 35, wherein the laminated quartz or glass substrate is inclined at a Brewster angle with respect to the substrate.

36. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 35, wherein the multi-coated substrate is coated with an inorganic film.

20. The light irradiation device for forming an alignment film of a liquid crystal display element according to claim 19, which is a glass substrate, a quartz substrate, or a multi-coated substrate on which the third polarizer is laminated.

39. The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 38, wherein the laminated quartz or glass substrate is inclined at a Brewster angle with respect to the substrate.

The light irradiation apparatus for forming an alignment film of a liquid crystal display element according to claim 38, wherein the multi-coated substrate is coated with an inorganic film.