JPH11337728A - Sheet-like polarizing element and liquid crystal display element using the same - Google Patents
Sheet-like polarizing element and liquid crystal display element using the sameInfo
- Publication number
- JPH11337728A JPH11337728A JP10141470A JP14147098A JPH11337728A JP H11337728 A JPH11337728 A JP H11337728A JP 10141470 A JP10141470 A JP 10141470A JP 14147098 A JP14147098 A JP 14147098A JP H11337728 A JPH11337728 A JP H11337728A
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- Prior art keywords
- film
- angle
- liquid crystal
- sheet
- polarization
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、非偏光光から一方
向の偏光成分のみを生成する機能を備えた微細加工性に
優れたシート状偏光素子に関する。本発明のシート状偏
光素子は偏光光束を必要とする任意の用途に使用され得
るが、特に、液晶表示素子のバックライト側に配置され
る偏光板に用いて有利なものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet-shaped polarizing element having a function of generating only a polarized light component in one direction from non-polarized light and having excellent fine workability. The sheet-like polarizing element of the present invention can be used for any application requiring a polarized light beam, and is particularly advantageous for use in a polarizing plate arranged on the backlight side of a liquid crystal display element.
【０００２】[0002]
【従来の技術】従来、液晶パネルディスプレイに用いら
れる偏光板は、ヨウ素会合体または二色性色素が基材の
高分子フィルム中に吸着され、１軸方向に延伸処理され
ている。偏光板に入射した光のうち吸収軸方向の偏光成
分を有する光は吸収遮断され、それと直交する偏光成分
は透過する。したがって、原理的には入射光の透過率は
50％となる。実際広く市販されている偏光板の透過率は
４０から４５％である。すなわち、バックライトの光量
の約半分が偏光板により損失されるのが現状である。こ
のため表示画面の輝度を上げるにはバックライト光源の
出力を増加させる必要があり、省電力化に逆行するもの
である。2. Description of the Related Art Hitherto, a polarizing plate used for a liquid crystal panel display has an iodine association or a dichroic dye adsorbed in a polymer film as a base material and is stretched in a uniaxial direction. Of the light incident on the polarizing plate, light having a polarization component in the absorption axis direction is absorbed and blocked, and a polarization component orthogonal to the light is transmitted. Therefore, in principle, the transmittance of incident light is
50%. In fact, the transmittance of widely commercially available polarizing plates is 40 to 45%. That is, at present, about half of the light amount of the backlight is lost by the polarizing plate. Therefore, in order to increase the brightness of the display screen, it is necessary to increase the output of the backlight light source, which goes against power saving.
【０００３】光の利用効率を促進するための１つの技術
が、特開平８−２４８２２４号公報に示されており、こ
こでは２つの偏光成分を有する光を屈折率の異なる物質
境界で透過光と反射光にし、１つの偏光成分を位相変化
を行う位相子やファラデー素子等により偏波面を回転さ
せた後に、２つの偏光成分を同方向に進行するように方
向を変化させることにより、光源の光利用効率を高めて
いる。One technique for promoting light use efficiency is disclosed in Japanese Patent Application Laid-Open No. Hei 8-248224, in which light having two polarization components is separated from transmitted light by a material boundary having a different refractive index. By turning the plane of polarization with a phase shifter or Faraday element that changes the phase of one polarization component into reflected light, and then changing the direction so that the two polarization components travel in the same direction, the light of the light source Improves usage efficiency.
【０００４】しかしながら、この技術は偏波面を変換す
る位相子またはファラデー素子の波長依存性により、光
源波長により偏波面回転の分散が生じ、広帯域の波長に
対する光利用効率の向上が望めない。However, in this technique, the rotation of the polarization plane is dispersed depending on the wavelength of the light source due to the wavelength dependence of the phase shifter or the Faraday element that converts the polarization plane, and it is not expected to improve the light use efficiency with respect to a wide band wavelength.
【０００５】一方で偏光変調部として液晶の光学特性
（複屈折性及び旋光性）を活用する方法が特開平３−５
７０７号公報、特開平３−４１４１７号公報に示されて
いるが、液晶配列を制御する方法としては配向膜表面を
機械的に擦る方法であるラビング法（例えば、液晶ディ
スプレイの最先端、シグマ出版、83〜84頁の記事参照）
になるため、微細加工した表面への適用は不可能であっ
た。On the other hand, Japanese Patent Laid-Open No. 3-5 / 1990 discloses a method for utilizing the optical characteristics (birefringence and optical rotation) of a liquid crystal as a polarization modulator.
No. 707 and Japanese Patent Application Laid-Open No. 3-41417, as a method for controlling the liquid crystal alignment, a rubbing method that mechanically rubs the surface of an alignment film (for example, the most advanced liquid crystal display, Sigma Publishing, , Pages 83-84)
Therefore, application to a microfabricated surface was impossible.
【０００６】また、偏光変調部のような機能性膜を部分
選択的に形成する技術としては半導体プロセスに代表さ
れるレジスト技術があるが、行程が煩雑であり更には幾
何学的な構造の選択的成膜には限界があるため、製造プ
ロセスの簡略化は期待できない。As a technique for selectively forming a functional film such as a polarization modulator, there is a resist technique typified by a semiconductor process. However, the process is complicated and the selection of a geometrical structure is required. Since there is a limit to the film formation, simplification of the manufacturing process cannot be expected.
【０００７】[0007]
【発明が解決しようとする課題】本発明は偏光板の透過
率が低く、偏光板を用いた液晶表示装置の輝度向上には
バックライトの電力を高める必要がある、などの問題点
を解決するためになされたものであり、その目的とする
ところは広帯域で偏光板の透明性を大幅に増加させるこ
とにより、輝度向上 もしくはバックライトの電力の低
減化を図った液晶表示素子を提供することにある。The present invention solves the problems that the transmittance of a polarizing plate is low, and it is necessary to increase the power of a backlight in order to improve the brightness of a liquid crystal display device using the polarizing plate. The purpose of the invention is to provide a liquid crystal display device that improves the brightness or reduces the power of the backlight by greatly increasing the transparency of the polarizing plate over a wide band. is there.
【０００８】[0008]
【課題を解決するための手段】本発明のシート状偏光素
子は、直角三角形状の三角柱がアレイ状に配列されてお
り、前記三角柱の斜面に低屈折率、高屈折率材料が積層
された偏光分離膜が形成され、前記三角柱の偏光分離膜
を介した斜面と前記三角柱の垂直面に誘電体薄膜から成
る斜方蒸着膜が形成され、更に、前記三角柱上の斜方蒸
着膜を介した垂直面上に１／４らせん構造を有した分子
配向状態にある液晶分子を重合固定した薄膜からなる偏
光変調部が形成されたプリズムアレイから成るシート状
偏光素子において、偏光分離膜を介して前記三角柱の斜
面上に作製された斜方蒸着膜と前記三角柱の垂直面上に
作製された斜方蒸着膜の蒸着角度が異なり、更に前記三
角柱の垂直面の蒸着角度よりも斜面の蒸着角度が大きい
ことを特徴とする。According to the present invention, there is provided a sheet-like polarizing element in which triangular prisms having a right-angled triangular shape are arranged in an array, and a low-refractive-index and high-refractive-index material is laminated on the slope of the triangular prism. An isolation film is formed, an oblique deposition film made of a dielectric thin film is formed on a slope of the triangular prism via the polarization separation film and a vertical surface of the triangular prism, and further, a vertical deposition film on the triangular prism via the oblique deposition film. In a sheet-like polarizing element comprising a prism array in which a polarization modulating portion formed of a thin film formed by polymerizing and fixing liquid crystal molecules in a molecular alignment state having a せ ん helical structure on the surface, the triangular prism is provided via a polarization separation film. The deposition angle of the oblique deposition film produced on the slope of the oblique deposition film and the deposition angle of the oblique deposition film produced on the vertical surface of the triangular prism are different, and the deposition angle of the slope is larger than the vapor deposition angle of the vertical surface of the triangular prism. Characterized by
【０００９】また、誘電体薄膜から成る斜方蒸着膜にお
いて斜方蒸着角度が蒸着物被着面の法線に対し４５゜か
ら８０°に傾斜した角度の入射角で斜方蒸着されること
を特徴とする。Further, in the obliquely deposited film formed of a dielectric thin film, the obliquely deposited angle is obliquely deposited at an incident angle inclined from 45 ° to 80 ° with respect to the normal to the surface on which the deposit is to be deposited. Features.
【００１０】また、誘電体薄膜から成る斜方蒸着膜にお
いて誘電体薄膜の成膜速度が１．５ｎｍ／ｓから３．０
ｎｍ／ｓであることを特徴とする。In the obliquely deposited film made of a dielectric thin film, the film forming speed of the dielectric thin film is from 1.5 nm / s to 3.0 nm.
nm / s.
【００１１】また、誘電体薄膜から成る斜方蒸着膜にお
いて、偏光変調部を構成する液晶分子の未重合体との接
触角が、偏光分離膜を介して前記三角柱の斜面上に作製
された斜方蒸着膜上と前記三角柱の垂直面上に作製され
た斜方蒸着膜上とで異なり、偏光分離膜を介して前記三
角柱の斜面上に作製された斜方蒸着膜と偏光変調部を構
成する液晶分子の未重合体とのなす接触角が１１°以上
であり、更に、前記三角柱の垂直面上に作製された斜方
蒸着膜と偏光変調部を構成する液晶分子の未重合体との
なす接触角が１１°より小さいことを特徴とする。Further, in the obliquely deposited film made of a dielectric thin film, the contact angle of the liquid crystal molecules constituting the polarization modulator with the unpolymer is determined via the polarization separation film on the slope of the triangular prism. The obliquely deposited film formed on the inclined surface of the triangular prism is different from the obliquely deposited film formed on the vertical surface of the triangular prism, and forms a polarization modulation unit with the obliquely deposited film manufactured on the inclined surface of the triangular prism via a polarization separation film. The contact angle between the liquid crystal molecules and the non-polymer is 11 ° or more, and further, the oblique deposition film formed on the vertical surface of the triangular prism and the non-polymer of the liquid crystal molecules forming the polarization modulator are formed. The contact angle is smaller than 11 °.
【００１２】また、直角三角形の一つの頂角が４０゜か
ら５０°であることを特徴とする。[0012] Further, the vertical angle of one of the right triangles is 40 ° to 50 °.
【００１３】また、誘電体薄膜から成る斜方蒸着膜が無
機酸化物または無機フッ化物または無機酸化物及び無機
フッ化物の複合物のうちの少なくとも一つから構成され
ることを特徴とする。[0013] Further, the obliquely deposited film formed of the dielectric thin film is characterized by comprising at least one of an inorganic oxide or an inorganic fluoride or a composite of an inorganic oxide and an inorganic fluoride.
【００１４】シート状偏光素子において偏光面が一致し
た透過光と反射光が出射する面に、出射光の偏光面と偏
光板の偏光軸が一致するように偏光板を設けるとよい。It is preferable to provide a polarizing plate on the surface of the sheet-like polarizing element from which the transmitted light and the reflected light whose polarization planes coincide with each other are emitted, so that the polarization plane of the emitted light coincides with the polarization axis of the polarizing plate.
【００１５】液晶表示素子にシート状偏光素子を液晶セ
ルを挟んで配置される偏光板の光源側の偏光素子として
用いるとよい。It is preferable to use a sheet-like polarizing element as a polarizing element on the light source side of a polarizing plate arranged with a liquid crystal cell interposed therebetween in a liquid crystal display element.
【００１６】[0016]
【発明の実施の形態】図１は本発明のシート状偏光素子
の構造図であり、１は頂角が４０から５０゜の直角三角
形状の三角柱がアレイ状に配置されたプリズムシートで
ある。このプリズムシートはプラスチック成形加工技術
をもって作製することができる。あるいは ガラスから
成る長尺のプリズムをアレイ状に配列することにより容
易に製作することができる。FIG. 1 is a structural view of a sheet-like polarizing element according to the present invention. Reference numeral 1 denotes a prism sheet in which triangular prisms having a right angle of 40 to 50 ° are arranged in an array. This prism sheet can be manufactured by plastic molding technology. Alternatively, it can be easily manufactured by arranging long prisms made of glass in an array.
【００１７】アレイ状に配列されたプリズムシートの頂
角は４０゜から５０゜が好ましく、頂角が５０゜より大
きいと三角柱の垂直面に形成される偏光変調部への入射
光量が低下しシート状偏光素子としての光利用効率が低
下してしまう。また、頂角が４０゜より小さいとプリズ
ムアレイシートの成形加工が困難になり、更に、入射光
の進行方向も複雑になるため光学的な損失が大きくなり
シート状偏光素子としての光利用効率が低下してしま
う。The apex angle of the prism sheets arranged in an array is preferably from 40 ° to 50 °, and if the apex angle is greater than 50 °, the amount of light incident on the polarization modulator formed on the vertical surface of the triangular prism decreases, and the sheet angle decreases. The light utilization efficiency as a squaring polarizing element is reduced. On the other hand, if the apex angle is smaller than 40 °, it is difficult to form the prism array sheet, and the traveling direction of the incident light becomes complicated, so that the optical loss becomes large and the light use efficiency as the sheet-shaped polarizing element is reduced. Will drop.
【００１８】シート状プリズムアレイ１には、三角柱の
斜面に低屈折率、高屈折率の薄膜から成る偏光分離膜
２、斜面上の偏光分離膜上に形成された誘電体薄膜から
成る斜方蒸着膜３、偏光分離膜上に形成された斜方蒸着
膜の蒸着角度より小さい入射角により直角プリズムの入
射光と平行な面に形成された斜方蒸着膜４および斜方蒸
着膜４上に形成される１／４らせん構造を有した分子配
向状態にある液晶分子を重合固定した薄膜からなる偏光
変調部５が形成される。In the sheet-like prism array 1, a polarization separation film 2 composed of a thin film having a low refractive index and a high refractive index is formed on the slope of the triangular prism, and an oblique vapor deposition composed of a dielectric thin film formed on the polarization separation film on the slope. The film 3, the obliquely deposited film 4 formed on a plane parallel to the incident light of the right-angle prism with an incident angle smaller than the deposition angle of the obliquely deposited film formed on the polarization separation film, and formed on the obliquely deposited film 4 As a result, the polarization modulator 5 formed of a thin film formed by polymerizing and fixing liquid crystal molecules in a molecular alignment state having a ４ helical structure is formed.
【００１９】低屈折率、高屈折率の薄膜から成る偏光分
離膜２には、低屈折率である材料としては硫化亜鉛、酸
化セリウム、酸化チタンなど、低屈折率である材料とし
てはフッ化マグネシウム、フッ化ネオジュウムなどが使
われる。成膜方法としては真空蒸着、もしくはスパッタ
リングが用いられる。交互に積層する高、低屈折率薄膜
の各々の膜厚、層数は偏光分離膜の性能を設計する上で
重要である。The polarizing beam splitting film 2 composed of a thin film having a low refractive index and a high refractive index includes a material having a low refractive index such as zinc sulfide, cerium oxide and titanium oxide, and a material having a low refractive index such as magnesium fluoride. , Neodymium fluoride and the like are used. Vacuum evaporation or sputtering is used as a film formation method. The thickness and the number of layers of the high and low refractive index thin films alternately laminated are important in designing the performance of the polarization splitting film.
【００２０】１／４らせん構造を有した分子配向状態に
ある液晶分子を重合固定した薄膜からなる偏光変調部５
は入射偏光面を 90度回転する機能をもつ光学変調部で
あり、構成する液晶分子の液晶相の分子配向状態を配向
固定化するために重合官能基を有することが望ましく、
重合官能基としてアクリレート基、メタクリレート基、
ビニルエーテル基またはエポキシ基のうち少なくとも一
つ以上有していることが好ましい。また、液晶分子は１
／４らせん構造を発現するためにコレステリック液晶が
好ましく、カイラルネマティック液晶、カイラルスメク
ティック液晶、ネマチック液晶とカイラル剤の混合物、
スメクティック液晶とカイラル剤の混合物がより好まし
い。A polarization modulator 5 comprising a thin film in which liquid crystal molecules in a molecular alignment state having a １ ／ helical structure are polymerized and fixed.
Is an optical modulator having a function of rotating the incident polarization plane by 90 degrees, and desirably has a polymerizable functional group in order to fix the molecular alignment state of the liquid crystal phase of the constituting liquid crystal molecules,
Acrylate group, methacrylate group,
It preferably has at least one of a vinyl ether group and an epoxy group. The liquid crystal molecules are 1
Cholesteric liquid crystals are preferred for expressing a / 4 helical structure, and chiral nematic liquid crystals, chiral smectic liquid crystals, mixtures of nematic liquid crystals and chiral agents,
Mixtures of smectic liquid crystals and chiral agents are more preferred.
【００２１】偏光分離膜２およびアレイ１の垂直面上に
形成される斜方蒸着膜３および４の作製方法は蒸着法が
好ましい。蒸着方法としては蒸着粒子の基板に対する付
着成長方位に指向性がある成膜方法が好ましく、抵抗加
熱蒸着法または電子線蒸着法が特に好ましい。The oblique deposition films 3 and 4 formed on the vertical plane of the polarization separation film 2 and the array 1 are preferably formed by a deposition method. As the vapor deposition method, a film formation method having directivity in the direction of attachment and growth of the vapor deposition particles to the substrate is preferable, and a resistance heating vapor deposition method or an electron beam vapor deposition method is particularly preferable.
【００２２】また、誘電体薄膜からなる斜方蒸着膜３お
よび４の蒸着角度は４５゜から８０゜の入射角度で成膜
され、斜方蒸着膜３の入射角度より斜方蒸着膜４の入射
角度が小さい組み合わせで成膜され、更に斜方蒸着膜３
と偏光変調部５を構成する液晶分子の未重合体との接触
角が１１゜以上であり、斜方蒸着膜４と偏光変調部５を
構成する液晶分子の未重合体との接触角が１１゜より小
さいことが好ましい。更に好ましくは斜方蒸着膜３の蒸
着角度が７０゜から８０゜の入射角度であり、斜方蒸着
膜４の蒸着角度が４５゜から７０゜の入射角度であっ
て、かつ斜方蒸着膜３の入射角度より斜方蒸着膜４の入
射角度が小さい組み合わせで成膜され、斜方蒸着膜３と
偏光変調部５を構成する液晶分子の未重合体との接触角
が１１゜以上であり、斜方蒸着膜４と偏光変調部５を構
成する液晶分子の未重合体との接触角が１１゜より小さ
いとよい。The obliquely deposited films 3 and 4 made of a dielectric thin film are formed at an incident angle of 45 ° to 80 °, and the incident angle of the obliquely deposited film 4 is larger than the incident angle of the obliquely deposited film 3. Films are formed in a combination with a small angle, and further, an obliquely deposited film 3
And the contact angle between the non-polymer of the liquid crystal molecules forming the polarization modulation section 5 is 11 ° or more, and the contact angle between the obliquely deposited film 4 and the non-polymer of the liquid crystal molecules forming the polarization modulation section 5 is 11 °. It is preferably smaller than ゜. More preferably, the deposition angle of the oblique deposition film 3 is 70 ° to 80 °, the deposition angle of the oblique deposition film 4 is 45 ° to 70 °, and the oblique deposition film 3 And the contact angle between the obliquely deposited film 3 and the unpolymerized liquid crystal molecules constituting the polarization modulator 5 is 11 ° or more; It is preferable that the contact angle between the obliquely deposited film 4 and the unpolymerized liquid crystal molecules constituting the polarization modulator 5 is smaller than 11 °.
【００２３】斜方蒸着膜３を作製する際の蒸着角度によ
り、偏光変調部５を構成する液晶分子の未重合体との接
触角が１１゜より小さくなると、偏光変調部５を構成す
る液晶分子の未重合体が偏光分離膜２上に接触した際
に、斜方蒸着膜３との親和性が良いためにはじかれずに
偏光分離膜２を介して残ってしまい、本来必要とされる
三角柱の垂直面上以外にも偏光変調部５が形成されてし
まう。また、斜方蒸着膜４を作製する際の蒸着角度によ
り、偏光変調部５を構成する液晶分子の未重合体との接
触角が１１゜以上になると、偏光変調部５を構成する液
晶分子の未重合体が斜方蒸着膜４上に接触した際に、斜
方蒸着膜４との親和性が悪いためにはじかれてしまい、
本来必要とされる三角柱の垂直面に偏光変調部５が形成
されない。When the contact angle of the liquid crystal molecules constituting the polarization modulator 5 with the unpolymer becomes smaller than 11 ° due to the deposition angle at the time of forming the oblique deposition film 3, the liquid crystal molecules constituting the polarization modulator 5 are formed. When the unpolymer is in contact with the polarized light separating film 2, it remains through the polarized light separating film 2 without being repelled because of its good affinity with the obliquely deposited film 3, and the triangular prism which is originally required The polarization modulator 5 is formed on a portion other than the vertical surface. When the contact angle of the liquid crystal molecules constituting the polarization modulator 5 with the non-polymer becomes 11 ° or more due to the vapor deposition angle at the time of producing the oblique deposition film 4, When the unpolymer comes into contact with the obliquely deposited film 4, it is repelled because of poor affinity with the obliquely deposited film 4,
The polarization modulator 5 is not formed on the vertical plane of the triangular prism that is originally required.
【００２４】つまり、斜方蒸着膜３は流動性を有する液
晶分子を重合固定化することから得られる偏光変調部５
の偏光分離膜２が形成されている斜面上への形成を抑制
する機能を有する。斜方蒸着膜３は液晶分子との親和性
が低く、そのため偏光変調部を構成する液晶分子の未重
合体は斜方蒸着膜３上での濡れ性が悪くはじかれてしま
い成膜性が低い。斜方蒸着膜３の蒸着角度が７０゜から
８０゜の入射角度であることが好ましく。斜方蒸着膜３
の入射角度が７０゜より小さい場合は、偏光変調部５を
構成する液晶分子との親和性が高まり、斜面上への偏光
変調部の形成を抑制する機能は低下する。That is, the obliquely deposited film 3 is a polarization modulator 5 obtained by polymerizing and fixing liquid crystal molecules having fluidity.
Has a function of suppressing the formation on the inclined surface on which the polarization separation film 2 is formed. The obliquely deposited film 3 has a low affinity for the liquid crystal molecules, so that the non-polymer of the liquid crystal molecules constituting the polarization modulator is repelled with poor wettability on the obliquely deposited film 3 and has poor film formability. . Preferably, the deposition angle of the oblique deposition film 3 is an incident angle of 70 ° to 80 °. Oblique deposition film 3
When the angle of incidence is smaller than 70 °, the affinity for the liquid crystal molecules constituting the polarization modulation section 5 is increased, and the function of suppressing the formation of the polarization modulation section on the slope is reduced.
【００２５】一方、斜方蒸着膜４は偏光変調部５を構成
する液晶分子を配向させる機能を有する。斜方蒸着によ
る構造異方性により液晶分子の配向性が発現する。斜方
蒸着膜４の蒸着角度が４５゜から７０゜の入射角度であ
ることが好ましく。蒸着角度が４５゜より小さい場合
は、液晶分子との濡れ性は良好であるが液晶分子の配向
規制力が低下してしまう。また、蒸着角度が７０゜より
大きい場合は液晶分子の濡れ性が低下してはじかれてし
まい偏光変調部の形成ができない。On the other hand, the obliquely deposited film 4 has a function of aligning the liquid crystal molecules constituting the polarization modulator 5. The orientation of the liquid crystal molecules is exhibited by the structural anisotropy due to the oblique deposition. It is preferable that the angle of deposition of the obliquely deposited film 4 is 45 ° to 70 °. When the deposition angle is smaller than 45 °, the wettability with the liquid crystal molecules is good, but the alignment regulating force of the liquid crystal molecules is reduced. On the other hand, when the vapor deposition angle is larger than 70 °, the wettability of the liquid crystal molecules is reduced and the liquid crystal molecules are repelled, so that the polarization modulation section cannot be formed.
【００２６】斜方蒸着膜３および４の誘電体薄膜の成膜
速度は１．５ｎｍ／ｓから３．０ｎｍ／ｓであることが
好ましく。成膜速度が１．５ｎｍ／ｓより小さい場合は
斜方蒸着による構造異方性が小さくなり配向規制力およ
び液晶分子との親和性の両立ができない。また、成膜速
度が３．０ｎｍ／ｓより大きい場合は斜方蒸着による構
造異方性が極端に大きくなり配向規制力および液晶分子
との親和性の両立ができない。The deposition rate of the dielectric thin films of the obliquely deposited films 3 and 4 is preferably from 1.5 nm / s to 3.0 nm / s. If the deposition rate is less than 1.5 nm / s, the structural anisotropy due to oblique deposition is reduced, and it is not possible to achieve both the alignment control force and the affinity with the liquid crystal molecules. On the other hand, when the film formation rate is higher than 3.0 nm / s, the structural anisotropy due to the oblique vapor deposition becomes extremely large, and it is impossible to achieve both the alignment regulating force and the affinity with the liquid crystal molecules.
【００２７】斜方蒸着膜３および４を構成する材料とし
ては、斜方蒸着による構造異方性を発現し易いものが好
ましく、酸化タンタル、酸化タングステン、酸化珪素、
酸化チタンなどの無機酸化物を斜方蒸着したもの、フッ
化マグネシウム、フッ化ネオジュウムなど無機フッ化物
を斜方蒸着したものが特に好ましい。The material constituting the obliquely deposited films 3 and 4 is preferably a material which easily develops structural anisotropy by obliquely deposited film. Tantalum oxide, tungsten oxide, silicon oxide,
Particularly preferred are those obtained by obliquely vapor-depositing an inorganic oxide such as titanium oxide and those obliquely vapor-deposited with an inorganic fluoride such as magnesium fluoride and neodymium fluoride.
【００２８】本発明の偏光素子の構造断面図である図２
により、本発明の機能を説明する。FIG. 2 is a structural sectional view of the polarizing element of the present invention.
The function of the present invention will be described below.
【００２９】偏光していない光（自然光）６が第一のプ
リズム１１の斜面に入射すると斜方蒸着膜３を透過し、
偏光分離膜２が形成されているプリズム斜面で反射およ
び屈折し、反射光７および屈折光８に分離される。反射
光７および屈折光８の偏光状態および光強度は、偏光分
離膜２の構成、すなわち高、低屈折率の値、膜厚および
層数により決定される。ここで偏光分離膜２を、反射光
７のｓ偏光成分が多くなるよう、また、屈折光８のｐ偏
光成分は多くなるように設計する。反射光７は１／４ら
せん構造を有した分子配向状態にある液晶分子を配向固
定した薄膜からなる偏光変調部４の作用によりｓ、ｐ偏
光成分が逆転し、その結果ｐ偏光成分は多くなり、透過
光９として隣接した第二のプリズム１２に入射し、その
斜面で全反射され、偏光光９’となる。この際、偏光状
態は変化しない。When unpolarized light (natural light) 6 enters the inclined surface of the first prism 11, it passes through the obliquely deposited film 3,
The light is reflected and refracted by the inclined surface of the prism on which the polarization separation film 2 is formed, and is separated into reflected light 7 and refracted light 8. The polarization state and light intensity of the reflected light 7 and the refracted light 8 are determined by the configuration of the polarization separation film 2, that is, the values of the high and low refractive indexes, the film thickness, and the number of layers. Here, the polarization separation film 2 is designed so that the s-polarized light component of the reflected light 7 increases and the p-polarized light component of the refracted light 8 increases. In the reflected light 7, the s and p polarization components are reversed by the action of the polarization modulator 4 composed of a thin film in which liquid crystal molecules in a molecular alignment state having a ら helical structure are aligned and fixed. As a result, the p polarization component increases. , As transmitted light 9, is incident on the adjacent second prism 12, and is totally reflected by the inclined surface to become polarized light 9 ′. At this time, the polarization state does not change.
【００３０】更に、ｐ偏光が通過するように配置され
た、偏光板２０を通り、射出光１０となる。この射出光
１０はｐ偏光のみを偏光成分としてもつ直線偏光光であ
る。一方、屈折光８はｐ偏光成分とｓ偏光成分からなる
楕円偏光であるが、偏光分離膜２の作用によりそのｓ偏
光強度は反射光７のｓ偏光強度に比し十分に低い。屈折
光８は反射光の場合と同様偏光板５を経て、ｐ偏光成分
のみを有する直線偏光光１３として射出する。反射光７
が偏光変換された直線偏光光１０と屈折光８による直線
偏光光１３を加え合わせ、直線偏光光源として利用でき
る。すなわち入射自然光６は偏光分離膜２を有した斜面
で偏光分離され、更に反射光の偏光面変調により直線偏
光光に変換される。その変換効率は50％以上、典型的に
は80％程度の値が得られる。Further, the light passes through the polarizing plate 20 arranged so that the p-polarized light passes therethrough, and becomes the emitted light 10. The emitted light 10 is linearly polarized light having only p-polarized light as a polarization component. On the other hand, the refracted light 8 is elliptically polarized light composed of a p-polarized light component and an s-polarized light component, and the s-polarized light intensity is sufficiently lower than the s-polarized light intensity of the reflected light 7 due to the action of the polarization separation film 2. The refracted light 8 passes through the polarizing plate 5 as in the case of the reflected light, and is emitted as linearly polarized light 13 having only a p-polarized component. Reflected light 7
Can be used as a linearly polarized light source by combining the linearly polarized light 10 whose polarization has been converted and the linearly polarized light 13 due to the refracted light 8. That is, the incident natural light 6 is polarization-separated on the slope having the polarization separation film 2 and further converted into linearly polarized light by polarization plane modulation of the reflected light. Its conversion efficiency is at least 50%, typically about 80%.
【００３１】つまり、本発明のシート状偏光素子によ
り、非偏光光からｐ偏光成分の多い透過光で出射させｓ
偏光成分の多い反射光をｐ偏光に変換した後に出射させ
ることにより光エネルギーを損失させることなしに非偏
光光を一方向偏光に光利用効率を高く変換させることが
できる。また、１／４らせん構造の分子配向状態にある
液晶分子を配向固定した薄膜により偏光面の変調部が構
成されているため、広波長帯域で偏波面回転の分散の小
さい偏光面変換が可能になり、広帯域で光利用効率の向
上を得ることができる。That is, the sheet-like polarizing element of the present invention allows non-polarized light to be emitted as transmitted light having a large amount of p-polarized light.
By converting reflected light having a large amount of polarized light into p-polarized light and then emitting the light, non-polarized light can be converted into unidirectional polarized light with high light utilization efficiency without loss of light energy. In addition, since the polarization plane modulation section is formed by a thin film in which liquid crystal molecules in a 1/4 helix molecular orientation state are fixed, the polarization plane conversion with a small dispersion of polarization plane rotation in a wide wavelength band is possible. That is, the light use efficiency can be improved in a wide band.
【００３２】[0032]
【実施例】次に、実施例に基づき本発明を詳細に説明す
る。但し、本発明は以下の実施例に限定されるものでは
ない。直角の２辺が２ｍｍである直角２等辺三角形を断
面とし、面積１０ｃｍｘ１０ｃｍにプリズムがアレイ状
に配列したシートを金型成形法により成形した。成形樹
脂はポリメチルメタクリレート（ＰＭＭＡ）であり光硬
化法によって成形した。プリズムシートに垂直方向から
蒸着することにより、斜面のみに高屈折率薄膜材料であ
る硫化亜鉛（Ｈと略記する）０．０５μｍおよび低屈折
率薄膜材料であるフッ化マグネシウム（Ｌと略記する）
を０．０９μｍをＨＬＨＬＨＬＨＬＨの順に９層積層し
偏光分離膜を作製した。成膜は２つの蒸発源を有する真
空蒸着法によりおこなった。プリズムアレイ斜面のみに
斜面の法線方向から７５゜の蒸着角度で斜方蒸着ができ
るようにマスクを配置しフッ化マグネシウム斜方蒸着膜
を成膜速度２５ｎｍ／ｓでプリズムアレイ斜面の偏光分
離膜上に作製した。次に、プリズムアレイ垂直面のみに
垂直面の法線方向から６０゜の蒸着角度で斜方蒸着がで
きるようにマスクを配置しフッ化マグネシウム斜方蒸着
膜を成膜速度２５ｎｍ／ｓでプリズムアレイ垂直面に作
製した。成膜法は電子ビーム蒸着により行った。次に、
カイラル剤（CNL611L：旭電化社製）とモノアクリレー
ト液晶（UCL-001：ロディック社製）をｄ／ｐ＝１／４
に調整し、光硬化開始剤（IRG651：チバガイギー社製）
を液晶に対し２ｗｔ％に調整し、メチルエチルケトン溶
媒に溶解し液晶濃度１２ｗｔ％の塗布液を作製した。調
整した塗布液を斜方蒸着面に滴下し、溶媒蒸発後の液晶
滴と偏光分離膜上に形成された斜方蒸着膜の接触角は１
６°で、一方の垂直面上に形成した斜方蒸着膜の接触角
は１０°であった。斜方蒸着膜を表面に形成したプリズ
ムアレイ上に調整した塗布液を塗布加工した。斜面上で
は液晶がはじかれて垂直面にのみ液晶が塗布乾燥するの
で、プリズムアレイ垂直面に１／４らせん構造を有した
分子配向状態にある液晶分子からなる偏光変調部が作製
された。その後、ＵＶ光を照射することにより液晶分子
の配向状態を重合固定した。以上のプロセスで完成した
プリズムアレイシートに自然光を照射し、偏光分離・変
換の効率を測定した結果、その効率は８３％であった。
さらに本発明の偏光素子を液晶パネルのバックライト側
の偏光板と差し替え、その効果を比較した。その結果、
本発明のシート状偏光素子を挿入した場合の画像輝度が
明かに高いことが確認できた。Next, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the following examples. A sheet having a right-angled isosceles triangle having two right-angled sides of 2 mm as a cross section and prisms arranged in an area of 10 cm × 10 cm in an array was formed by a mold forming method. The molding resin was polymethyl methacrylate (PMMA) and was molded by a photo-curing method. By vapor deposition on the prism sheet from a vertical direction, 0.05 μm of zinc sulfide (abbreviated as H), which is a high-refractive-index thin film material, and magnesium fluoride (abbreviated as L), which is a low-refractive-index thin film material, is formed only on the slope.
Were laminated in the order of HLHLHLHLH in the order of HLHLHLHLH to form a polarization separation film. The film was formed by a vacuum evaporation method having two evaporation sources. A mask is arranged only on the prism array slope so that oblique deposition can be performed at a deposition angle of 75 ° from the normal direction of the slope, and a magnesium fluoride oblique deposition film is formed at a deposition rate of 25 nm / s. Made above. Next, a mask is arranged only on the vertical surface of the prism array so that oblique deposition can be performed at a deposition angle of 60 ° from the normal direction of the vertical surface, and a magnesium fluoride oblique deposition film is formed at a deposition rate of 25 nm / s. Fabricated on a vertical surface. The film was formed by electron beam evaporation. next,
A chiral agent (CNL611L: manufactured by Asahi Denka Co., Ltd.) and a monoacrylate liquid crystal (UCL-001: manufactured by Roddick) are d / p = 1/4.
, And a photo-curing initiator (IRG651: Ciba-Geigy)
Was adjusted to 2 wt% with respect to the liquid crystal, and dissolved in a methyl ethyl ketone solvent to prepare a coating liquid having a liquid crystal concentration of 12 wt%. The adjusted coating solution was dropped on the oblique deposition surface, and the contact angle between the liquid crystal droplet after evaporation of the solvent and the oblique deposition film formed on the polarization separation film was 1.
At 6 °, the contact angle of the obliquely deposited film formed on one vertical surface was 10 °. An adjusted coating solution was applied on a prism array having an obliquely deposited film formed on the surface. Since the liquid crystal was repelled on the inclined surface and the liquid crystal was applied and dried only on the vertical surface, a polarization modulation portion composed of liquid crystal molecules in a molecular alignment state having a quarter spiral structure on the vertical surface of the prism array was produced. Thereafter, the alignment state of the liquid crystal molecules was polymerized and fixed by irradiating UV light. The prism array sheet completed by the above process was irradiated with natural light, and the efficiency of polarization separation / conversion was measured. As a result, the efficiency was 83%.
Further, the polarizing element of the present invention was replaced with a polarizing plate on the backlight side of the liquid crystal panel, and the effects were compared. as a result,
It was confirmed that the image brightness when the sheet-like polarizing element of the present invention was inserted was clearly higher.
【００３３】[0033]
【発明の効果】本発明によると、自然光を非常に高い効
率で直線偏光光に変換できる。本発明のシート状偏光素
子を用いることにより、従来の偏光板を用いた場合に比
べ、液晶表示画面の輝度は30％ 程度向上した。つま
り、本発明のシート状偏光素子を用いることにより液晶
表示装置用バックライトの省電力化及び液晶表示画面の
高輝度化が得られる。According to the present invention, natural light can be converted into linearly polarized light with very high efficiency. By using the sheet-like polarizing element of the present invention, the brightness of the liquid crystal display screen was improved by about 30% as compared with the case where a conventional polarizing plate was used. That is, by using the sheet-shaped polarizing element of the present invention, power saving of a backlight for a liquid crystal display device and high luminance of a liquid crystal display screen can be obtained.
【図１】 本発明のシート状偏光素子の構造説明図FIG. 1 is a structural explanatory view of a sheet-like polarizing element of the present invention.
【図２】 本発明のシート状偏光素子の構造断面図FIG. 2 is a structural sectional view of a sheet-shaped polarizing element of the present invention.
１： プリズムシート ２： 偏光分離膜 ３： 蒸着角度の大きい斜方蒸着膜 ４： 蒸着角度が小さい斜方蒸着膜 ５： １／４らせん構造を有した分子配向状態にある液
晶分子の配向固定薄膜 ６： 自然光 ７： 反射光 ８： 屈折光 ９： 透過光 ９’： 偏光光 １０： 射出光 １１： 第一のプリズム １２： 第二のプリズム １３： 射出光 ２０： 偏光板1: prism sheet 2: polarization separation film 3: oblique evaporation film with a large evaporation angle 4: oblique evaporation film with a small evaporation angle 5: alignment fixed thin film of liquid crystal molecules in a molecular alignment state having a ら helical structure 6: natural light 7: reflected light 8: refracted light 9: transmitted light 9 ': polarized light 10: emission light 11: first prism 12: second prism 13: emission light 20: polarizing plate
Claims (8)
されており、前記三角柱の斜面に低屈折率、高屈折率材
料が積層された偏光分離膜が形成され、前記三角柱の偏
光分離膜を介した斜面と前記三角柱の垂直面に誘電体薄
膜から成る斜方蒸着膜が形成され、更に、前記三角柱上
の斜方蒸着膜を介した垂直面上に１／４らせん構造を有
した分子配向状態にある液晶分子を重合固定した薄膜か
らなる偏光変調部が形成されたプリズムアレイから成る
シート状偏光素子において、偏光分離膜を介して前記三
角柱の斜面上に作製された斜方蒸着膜と前記三角柱の垂
直面上に作製された斜方蒸着膜の蒸着角度が異なり、更
に前記三角柱の垂直面の蒸着角度よりも斜面の蒸着角度
が大きいことを特徴とするシート状偏光素子。1. A triangular prism having a right-angled triangular shape is arranged in an array, and a polarization separation film in which a low-refractive-index and a high-refractive-index material is laminated on an inclined surface of the triangular prism is formed. An oblique deposition film made of a dielectric thin film is formed on the intervening slope and a vertical surface of the triangular prism, and further, a molecular orientation having a せ ん helical structure on the vertical surface of the triangular prism via the oblique vapor deposition film. In a sheet-like polarizing element comprising a prism array in which a polarization modulation section composed of a thin film in which liquid crystal molecules in a state are polymerized and fixed is formed, an oblique deposition film formed on a slope of the triangular prism through a polarization separation film, and A sheet-like polarizing element, wherein a deposition angle of an obliquely deposited film formed on a vertical surface of a triangular prism is different, and a vapor deposition angle of a slope is larger than a vapor deposition angle of the vertical surface of the triangular prism.
斜方蒸着角度が蒸着物被着面の法線に対し４５゜から８
０°に傾斜した角度の入射角で斜方蒸着されることを特
徴とする請求項１記載のシート状偏光素子。2. An oblique deposition film made of a dielectric thin film, wherein an oblique deposition angle is 45 ° to 8 ° with respect to a normal to a surface on which a deposit is deposited.
2. The sheet-like polarizing element according to claim 1, wherein the oblique vapor deposition is performed at an incident angle inclined to 0 [deg.].
誘電体薄膜の成膜速度が１．５ｎｍ／ｓから３．０ｎｍ
／ｓであることを特徴とする請求項１記載のシート状偏
光素子。3. An obliquely deposited film made of a dielectric thin film, wherein the deposition rate of the dielectric thin film is from 1.5 nm / s to 3.0 nm.
The sheet-like polarizing element according to claim 1, wherein
て、偏光変調部を構成する液晶分子の未重合体との接触
角が、偏光分離膜を介して前記三角柱の斜面上に作製さ
れた斜方蒸着膜上と前記三角柱の垂直面上に作製された
斜方蒸着膜上とで異なり、偏光分離膜を介して前記三角
柱の斜面上に作製された斜方蒸着膜と偏光変調部を構成
する液晶分子の未重合体とのなす接触角が１１°以上で
あり、更に、前記三角柱の垂直面上に作製された斜方蒸
着膜と偏光変調部を構成する液晶分子の未重合体とのな
す接触角が１１°より小さいことを特徴とする請求項１
記載のシート状偏光素子。4. In an obliquely deposited film made of a dielectric thin film, a contact angle of a liquid crystal molecule constituting a polarization modulator with an unpolymer is determined on a slope formed on a slope of the triangular prism via a polarization separation film. The obliquely deposited film formed on the inclined surface of the triangular prism is different from the obliquely deposited film formed on the vertical surface of the triangular prism, and forms a polarization modulation unit with the obliquely deposited film produced on the inclined surface of the triangular prism via a polarization separation film. The contact angle between the liquid crystal molecules and the non-polymer is 11 ° or more, and further, the oblique deposition film formed on the vertical surface of the triangular prism and the non-polymer of the liquid crystal molecules forming the polarization modulator are formed. The contact angle is less than 11 degrees.
The sheet-shaped polarizing element as described in the above.
０°であることを特徴とする請求項１記載のシート状偏
光素子。5. The angle of one of the right triangles is 40 ° to 5 °.
The sheet-like polarizing element according to claim 1, wherein the angle is 0 °.
化物または無機フッ化物または無機酸化物及び無機フッ
化物の複合物のうちの少なくとも一つから構成されるこ
とを特徴とする請求項１記載のシート状偏光素子。6. An obliquely deposited film comprising a dielectric thin film, comprising at least one of an inorganic oxide, an inorganic fluoride, or a composite of an inorganic oxide and an inorganic fluoride. 2. The sheet-like polarizing element according to 1.
した透過光と反射光が出射する面に、出射光の偏光面と
偏光板の偏光軸が一致するように偏光板を設けた請求項
１記載のシート状偏光素子。7. A polarizing plate is provided on a surface of a sheet-like polarizing element from which transmitted light and reflected light whose polarization planes coincide with each other are emitted such that the polarization plane of the emitted light coincides with the polarization axis of the polarizing plate. The sheet-shaped polarizing element as described in the above.
ート状偏光素子を液晶セルを挟んで配置される偏光板の
光源側の偏光素子として用いた液晶表示素子。8. A liquid crystal display device using the sheet-like polarizing element according to claim 1 as a polarizing element on a light source side of a polarizing plate disposed with a liquid crystal cell interposed therebetween.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10141470A JPH11337728A (en) | 1998-05-22 | 1998-05-22 | Sheet-like polarizing element and liquid crystal display element using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10141470A JPH11337728A (en) | 1998-05-22 | 1998-05-22 | Sheet-like polarizing element and liquid crystal display element using the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11337728A true JPH11337728A (en) | 1999-12-10 |
Family
ID=15292643
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10141470A Pending JPH11337728A (en) | 1998-05-22 | 1998-05-22 | Sheet-like polarizing element and liquid crystal display element using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11337728A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8054416B2 (en) * | 2000-08-15 | 2011-11-08 | Reflexite Corporation | Light polarizer |
| US8657480B2 (en) * | 2008-12-09 | 2014-02-25 | Samsung Display Co., Ltd. | Display apparatus |
-
1998
- 1998-05-22 JP JP10141470A patent/JPH11337728A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8054416B2 (en) * | 2000-08-15 | 2011-11-08 | Reflexite Corporation | Light polarizer |
| US8657480B2 (en) * | 2008-12-09 | 2014-02-25 | Samsung Display Co., Ltd. | Display apparatus |
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