JP2003066450A - Liquid crystal element and optical attenuator - Google Patents
Liquid crystal element and optical attenuatorInfo
- Publication number
- JP2003066450A JP2003066450A JP2001256301A JP2001256301A JP2003066450A JP 2003066450 A JP2003066450 A JP 2003066450A JP 2001256301 A JP2001256301 A JP 2001256301A JP 2001256301 A JP2001256301 A JP 2001256301A JP 2003066450 A JP2003066450 A JP 2003066450A
- Authority
- JP
- Japan
- Prior art keywords
- liquid crystal
- light
- polarized light
- voltage
- linearly polarized
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Liquid Crystal (AREA)
- Polarising Elements (AREA)
- Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、液晶素子および光
減衰器に関し、特に光通信に用いる液晶素子および光減
衰器に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal element and an optical attenuator, and more particularly to a liquid crystal element and an optical attenuator used for optical communication.
【０００２】[0002]
【従来の技術】液晶を用いた従来の光減衰器の一例を図
６に示す。透明電極３、４が形成された透光性基板５と
６との間に液晶分子の配向方向が基板面に平行で、Ｘ軸
方向と４５°の角度をなす方向に揃ったネマティック液
晶の液晶層１が基板の周縁に設けられたシール材８の内
部に狭持された液晶セル１１０と、その光出射面側にＸ
軸方向に偏光方向を有する直線偏光のみを透過する偏光
子１２とを配置した構成となっている。2. Description of the Related Art FIG. 6 shows an example of a conventional optical attenuator using liquid crystal. Liquid crystal of nematic liquid crystal in which the alignment direction of the liquid crystal molecules is parallel to the substrate surface between the transparent substrates 5 and 6 on which the transparent electrodes 3 and 4 are formed, and which is aligned in a direction forming an angle of 45 ° with the X-axis direction. The liquid crystal cell 110 in which the layer 1 is sandwiched inside the sealing material 8 provided on the periphery of the substrate, and X is provided on the light emitting surface side thereof.
A polarizer 12 that transmits only linearly polarized light having a polarization direction in the axial direction is arranged.
【０００３】ここで、透明電極３と４とに矩形波出力の
交流電源９を接続し、この電源による電圧非印加時に、
波長λでＹ軸方向に偏光方向を有する直線偏光に対する
液晶セル１１０のリタデーション値がほぼλ／２となる
よう液晶層１の厚さｄｌｃが設定されている。ここで、
液晶層１のリタデーション値をほぼλ／２としているの
は、電圧非印加時に光減衰器の挿入損失を最小とするた
め、およびλ／２板として機能させるためである。Here, an AC power source 9 having a rectangular wave output is connected to the transparent electrodes 3 and 4, and when no voltage is applied by this power source,
The thickness dlc of the liquid crystal layer 1 is set so that the retardation value of the liquid crystal cell 110 for linearly polarized light having a polarization direction in the Y-axis direction at the wavelength λ is approximately λ / 2. here,
The reason why the retardation value of the liquid crystal layer 1 is approximately λ / 2 is to minimize the insertion loss of the optical attenuator when no voltage is applied and to function as a λ / 2 plate.
【０００４】この光減衰器において、透明電極間への電
圧非印加時に液晶層を透過したＹ軸方向に偏光した直線
偏光は、Ｘ軸方向に偏光方向を有する直線偏光となって
偏光子を透過する。電圧を印加するとき、印加電圧の増
加に伴い液晶層の厚さ方向に、すなわち基板に垂直にな
るように液晶分子の配向方向が傾く。それに伴い液晶層
のリタデーション値が減少し、液晶セル１１０を透過し
た光は楕円偏光となり、その結果、偏光子の透過光量が
印加電圧の増加に伴い単調に減少するため、電圧可変型
の光減衰器となる。In this optical attenuator, the linearly polarized light which is transmitted through the liquid crystal layer and which is polarized in the Y-axis direction when no voltage is applied between the transparent electrodes becomes linearly polarized light having a polarization direction in the X-axis direction and is transmitted through the polarizer. To do. When a voltage is applied, as the applied voltage increases, the alignment direction of the liquid crystal molecules tilts in the thickness direction of the liquid crystal layer, that is, perpendicular to the substrate. Along with this, the retardation value of the liquid crystal layer decreases, and the light transmitted through the liquid crystal cell 110 becomes elliptically polarized light. As a result, the amount of light transmitted by the polarizer monotonically decreases with an increase in applied voltage. Become a vessel.
【０００５】[0005]
【発明が解決しようとする課題】入射光の波長λが例え
ば１．３〜１．６μｍの領域にある光通信用の、液晶素
子を用いた光減衰器では、液晶セルのリタデーション値
をλ／２とするためには可視波長領域の光減衰器に比べ
て、液晶層を厚くする必要がある。その結果、電圧振幅
１０Ｖ以上の交流電圧を印加しても、液晶層の厚さ方向
に液晶分子の配向方向が充分揃わないので液晶セルのリ
タデーション値がゼロとならないため、偏光子を透過す
る偏光成分が存在し、消光比の高い光減衰器が得られな
い問題があった。In an optical attenuator using a liquid crystal element for optical communication in which the wavelength λ of incident light is in the range of 1.3 to 1.6 μm, for example, the retardation value of the liquid crystal cell is λ / In order to obtain 2, it is necessary to make the liquid crystal layer thicker than the optical attenuator in the visible wavelength region. As a result, even if an AC voltage with a voltage amplitude of 10 V or more is applied, the alignment direction of the liquid crystal molecules is not sufficiently aligned in the thickness direction of the liquid crystal layer, and the retardation value of the liquid crystal cell does not become zero. There is a problem that an optical attenuator having a high extinction ratio cannot be obtained due to the presence of the component.
【０００６】本発明は、上述の実情に鑑み高い消光比が
安定して実現できる、液晶素子およびそれを用いた光減
衰器を提供することを目的とする。SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal element and an optical attenuator using the same, which can stably realize a high extinction ratio in view of the above situation.
【０００７】[0007]
【課題を解決するための手段】本発明は、電極付き透光
性基板間に液晶層が狭持された液晶セルであり、かつ電
極間に印加する電圧をＶ１からＶ２（Ｖ１≠Ｖ２）まで
変化させたとき、液晶セルへ入射され透過される波長λ
の直線偏光に対するリタデーション値がＲ１からＲ
２（Ｒ１＞Ｒ２＞０）まで変化する液晶セルと、波長λ
の直線偏光に対するリタデーション値ＲがＲ１≧Ｒｖ≧
Ｒ２の関係にあるＲｖと、Ｒ＋Ｒｖ＝ｍ×λ（ｍ：整
数）の関係を満たす位相板と、を備えることを特徴とす
る液晶素子を提供する。The present invention is a liquid crystal cell in which a liquid crystal layer is sandwiched between transparent substrates with electrodes, and the voltage applied between the electrodes is from V 1 to V 2 (V 1 ≠ V 2 ) the wavelength λ that is incident on and transmitted through the liquid crystal cell when changed to V 2 )
Retardation values for linearly polarized light of R 1 to R
2 (R 1 > R 2 > 0) and a wavelength λ
Has a retardation value R for linearly polarized light of R 1 ≧ R v ≧
There is provided a liquid crystal element comprising: R v having a relationship of R 2 ; and a phase plate satisfying a relationship of R + R v = m × λ (m: integer).
【０００８】また、上記の液晶素子の光入射側または光
出射側の少なくとも一方の側に偏光子がさらに配置さ
れ、液晶層への印加電圧の増加に伴い出射光強度が減少
することを特徴とする光減衰器を提供する。Further, a polarizer is further disposed on at least one of the light incident side and the light emitting side of the liquid crystal element, and the intensity of emitted light decreases as the voltage applied to the liquid crystal layer increases. An optical attenuator is provided.
【０００９】[0009]
【発明の実施の形態】本発明の液晶素子は、次の構成を
有する液晶素子である。すなわち、液晶素子は、電極付
き透光性基板間に液晶層が狭持された液晶セルを備え、
その液晶セルは電極間にＶ１からＶ２（Ｖ１≠Ｖ２）ま
での電圧が印加されたとき、液晶セルへ入射され透過さ
れる波長λの直線偏光に対するリタデーション値がＲ１
からＲ ２（Ｒ１＞Ｒ２＞０）まで変化するものである。
さらに、液晶素子は、波長λの直線偏光に対するリタデ
ーション値Ｒが、Ｒ１≧Ｒｖ≧Ｒ２の関係にあるＲｖと
Ｒ＋Ｒｖ＝ｍ×λ（ｍ：整数）の関係を満たす位相板を
備えている。BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal element of the present invention has the following constitution.
It is a liquid crystal element which has. That is, the liquid crystal element has electrodes.
A liquid crystal cell in which a liquid crystal layer is sandwiched between transparent substrates,
The liquid crystal cell has V1To VTwo(V1≠ VTwo)
When a voltage is applied to the liquid crystal cell,
The retardation value for linearly polarized light of wavelength λ is R1
To R Two(R1> RTwo> 0).
Furthermore, the liquid crystal element has a retardation for linearly polarized light of wavelength λ.
The solution value R is R1≧ Rv≧ RTwoR in the relationshipvWhen
R + Rv= M × λ (m: integer)
I have it.
【００１０】本発明の液晶素子を、このように構成する
ことにより、液晶素子は低電圧で高い消光比を得ること
ができる。以下、図面を参照しながら、本発明の液晶素
子を詳細に説明する。By configuring the liquid crystal element of the present invention in this way, the liquid crystal element can obtain a high extinction ratio at a low voltage. Hereinafter, the liquid crystal device of the present invention will be described in detail with reference to the drawings.
【００１１】図１は本発明の液晶素子の構成例を示す側
面図である。透光性基板５と６の片面にそれぞれ透明電
極３と４が形成され、さらにその上に同一方向に配向処
理された配向膜（図示せず）が形成されて、シール材８
を用いてセル化される。さらに、セル内に常光屈折率ｎ
ｏ（ＬＣ）および異常光屈折率ｎｅ（ＬＣ）（ｎｏ（Ｌ
Ｃ）＜ｎｅ（ＬＣ））のネマティック液晶が注入されて
液晶層１とされ、基板と平行に液晶分子の配向方向の揃
った液晶セル１１０が得られる。FIG. 1 is a side view showing a structural example of a liquid crystal element of the present invention. The transparent electrodes 3 and 4 are formed on one surface of the translucent substrates 5 and 6, respectively, and an alignment film (not shown) subjected to an alignment treatment in the same direction is formed on the transparent electrodes 3 and 4, and the sealing material 8 is formed.
Are made into cells. In addition, the ordinary refractive index n
o (LC) and extraordinary refractive index n e (LC) (n o (L
A nematic liquid crystal of C) <n e (LC) is injected to form the liquid crystal layer 1, and a liquid crystal cell 110 in which the alignment directions of liquid crystal molecules are aligned parallel to the substrate is obtained.
【００１２】また、透光性基板６と７の対向するそれぞ
れの面に配向膜用の溶液を塗布した後、塗布膜に同一方
向の配向処理を施し配向膜（図示せず）とし、図示しな
いシール材を用いてセル化する。さらに、セル内に液晶
モノマーの溶液を注入し、セル内で基板と平行に液晶分
子の配向方向の揃った液晶モノマー層を形成する。この
液晶モノマー層に紫外線を照射し固化して、液晶分子の
配向方向が固定された高分子液晶層２を形成して位相板
１２０を得る。これにより液晶セル１１０と位相板１２
０とが積層された液晶素子１００が得られる。Further, after applying a solution for an alignment film to the respective surfaces of the transparent substrates 6 and 7 which face each other, the coating film is subjected to alignment treatment in the same direction to form an alignment film (not shown), which is not shown. Create cells using a sealant. Further, a liquid crystal monomer solution is injected into the cell to form a liquid crystal monomer layer in which the alignment directions of liquid crystal molecules are aligned parallel to the substrate in the cell. The liquid crystal monomer layer is irradiated with ultraviolet rays and solidified to form the polymer liquid crystal layer 2 in which the alignment direction of the liquid crystal molecules is fixed to obtain the phase plate 120. Accordingly, the liquid crystal cell 110 and the phase plate 12
A liquid crystal element 100 in which 0 and 0 are stacked is obtained.
【００１３】このとき、ネマティック液晶からなる液晶
層１の遅相軸方向（異常光屈折率ｎ ｅ（ＬＣ）を与える
方向）は図１および図２において入射光の偏光方向であ
るＹ軸方向に対して４５度方向とする。また、常光屈折
率ｎｏ（ＰＬＣ）と異常光屈折率ｎｅ（ＰＬＣ）（ｎｏ
（ＰＬＣ）＜ｎｅ（ＰＬＣ））の高分子液晶層２からな
る位相板の進相軸方向（常光屈折率ｎｏ（ＰＬＣ）方
向）が液晶層１の遅相軸方向と角度θをなすように形成
されている。なお、本発明で記載するリタデーション値
は、液晶層１の進相軸方向の偏光に対する光路長と、液
晶層１の遅相軸方向の偏光に対する光路長との差を示
し、負のリタデーション値も存在する。At this time, a liquid crystal composed of a nematic liquid crystal
Slow axis direction of layer 1 (refractive index of extraordinary light n eGive (LC)
Direction) is the polarization direction of the incident light in FIGS.
45 ° to the Y-axis direction. Ordinary refraction
Rate no(PLC) and extraordinary light refractive index ne(PLC) (no
(PLC) <ne(PLC)) polymer liquid crystal layer 2
Direction of the phase axis of the phase plate (the ordinary refractive index no(PLC)
Direction) forms an angle θ with the slow axis direction of the liquid crystal layer 1.
Has been done. The retardation value described in the present invention
Is the optical path length for polarized light in the fast axis direction of the liquid crystal layer 1 and
Shows the difference from the optical path length for polarized light in the slow axis direction of crystal layer 1.
However, there is also a negative retardation value.
【００１４】ここで、位相板の進相軸方向と液晶層１の
遅相軸方向とのなす角度θを４５度以内とすることが好
ましい。角度θを４５度以内とすることにより位相板の
リタデーション値Ｒは電圧印可時に存在するリタデーシ
ョン値Ｒｖを相殺する負の値となるが、４５度を越える
とＲは正の値となりＲｖを相殺することが困難となる。Here, it is preferable that the angle θ formed by the fast axis direction of the phase plate and the slow axis direction of the liquid crystal layer 1 is within 45 degrees. By setting the angle θ within 45 degrees, the retardation value R of the phase plate becomes a negative value that cancels out the retardation value R v existing when a voltage is applied, but when it exceeds 45 degrees, R becomes a positive value and R v becomes It will be difficult to offset.
【００１５】通常は高分子液晶層２の進相軸方向が液晶
層１の遅相軸方向と同じ（θ＝０）とする。すなわち、
高分子液晶層２の進相軸方向が、入射光の偏光方向に対
して４５度の角をなす。Usually, the fast axis direction of the polymer liquid crystal layer 2 is the same as the slow axis direction of the liquid crystal layer 1 (θ = 0). That is,
The fast axis direction of the polymer liquid crystal layer 2 forms an angle of 45 degrees with the polarization direction of incident light.
【００１６】ここで、波長λでＹ軸方向に偏光方向を有
する直線偏光の入射光に対して、交流電源９からの電圧
非印加時に液晶セル１１０のリタデーション値がほぼλ
／２となるように、液晶層１の厚さｄ（ＬＣ）を０．５
λ／Δｎ（ＬＣ）とする。ここでΔｎ（ＬＣ）＝ｎ
ｅ（ＬＣ）−ｎｏ（ＬＣ）である。Here, the retardation value of the liquid crystal cell 110 is approximately λ when a voltage is not applied from the AC power source 9 with respect to the incident light of linear polarization having the polarization direction in the Y-axis direction at the wavelength λ.
The thickness d (LC) of the liquid crystal layer 1 is set to 0.5 so that
Let λ / Δn (LC). Where Δn (LC) = n
a e (LC) -n o (LC ).
【００１７】このようにして得られた液晶セル１１０の
透明電極３と４に交流電源９から電圧振幅Ｖの矩形波の
交流電圧を印加したとき、液晶セル１１０のリタデーシ
ョン値は減少するがゼロでない有限の値Ｒｖとなる。電
圧振幅Ｖの印加電圧で液晶素子のリタデーション値をゼ
ロとするためには、このようなリタデーション値Ｒｖを
相殺するように位相板１２０のリタデーション値Ｒ（＝
−Ｒｖ）を調整すればよい。すなわち、高分子液晶層２
の進相軸方向が液晶層１の遅相軸方向と一致する場合
は、高分子液晶層２の厚さｄ（ＰＬＣ）をＲｖ／Δｎ
（ＰＬＣ）とすればよい。ここで、Δｎ（ＰＬＣ）＝ｎ
ｅ（ＰＬＣ）−ｎｏ（ＰＬＣ）である。一致しない場合
は実効的な△ｎ（ＰＬＣ）が小さな値となるため、ｄが
厚くなる。When a rectangular wave AC voltage having a voltage amplitude V is applied from the AC power supply 9 to the transparent electrodes 3 and 4 of the liquid crystal cell 110 thus obtained, the retardation value of the liquid crystal cell 110 decreases but is not zero. It is a finite value R v . In order to make the retardation value of the liquid crystal element zero by the applied voltage of the voltage amplitude V, the retardation value R (= of the phase plate 120 is set so as to cancel the retardation value R v.
-R v) may be adjusted. That is, the polymer liquid crystal layer 2
When the fast axis direction of the liquid crystal layer 1 coincides with the slow axis direction of the liquid crystal layer 1, the thickness d (PLC) of the polymer liquid crystal layer 2 is set to R v / Δn.
(PLC) may be used. Here, Δn (PLC) = n
a e (PLC) -n o (PLC ). If they do not match, the effective Δn (PLC) becomes a small value, and d becomes thick.
【００１８】リタデーション値Ｒｖが大きな場合、電圧
非印加時の液晶素子のリタデーション値がλ／２よりＲ
ｖだけ小さな値となるため、その減少分Ｒｖを考慮して
あらかじめ液晶セル１１０のリタデーション値がλ／２
＋Ｒｖとなるようにしてもよい。When the retardation value R v is large, the retardation value of the liquid crystal element when no voltage is applied is R from λ / 2.
Since the value becomes smaller by v , the retardation value of the liquid crystal cell 110 is previously set to λ / 2 in consideration of the decrease R v.
It may be + R v .
【００１９】このようにして得られた液晶素子１００に
波長λでＹ軸方向に偏光方向を有する直線偏光が入射
し、液晶素子１００の光出射側にＸ軸方向に偏光方向を
有する直線偏光のみを透過する偏光子を配置して光減衰
器する。これにより、電圧非印加時にはほとんどの光が
透過し、電圧印加時（印加電圧Ｖ）には偏光子によって
光が遮断され、このため、偏光子の消光比に相当する高
い消光比を有する光減衰器が実現でき、好ましい。The linearly polarized light having the polarization direction in the Y-axis direction at the wavelength λ enters the liquid crystal element 100 thus obtained, and only the linearly polarized light having the polarization direction in the X-axis direction is incident on the light exit side of the liquid crystal element 100. An optical attenuator is provided by arranging a polarizer that transmits light. As a result, most of the light is transmitted when no voltage is applied, and the light is blocked by the polarizer when a voltage is applied (applied voltage V). Therefore, optical attenuation having a high extinction ratio corresponding to the extinction ratio of the polarizer is achieved. Can be realized, which is preferable.
【００２０】上記の説明では、液晶素子のリタデーショ
ン値が、印加電圧ゼロのときはほぼλ／２であり、また
印加電圧Ｖのときはゼロとなる場合について説明した
が、リタデーション値がλ／２およびゼロとは異なる構
成でもよい。In the above description, the retardation value of the liquid crystal element is approximately λ / 2 when the applied voltage is zero and is zero when the applied voltage is V, but the retardation value is λ / 2. And may be different from zero.
【００２１】液晶セル１１０への印加電圧の範囲がＶ１
からＶ２（Ｖ１≠Ｖ２）までであって、このときリタデ
−ション値はＲ１からＲ２まで変化する。上記の電圧範
囲内の特定の電圧Ｖで高い消光比の光減衰器を得るため
に、電圧Ｖで発生する液晶セル１１０のリタデ−ション
値Ｒｖと位相板１２０のリタデーション値Ｒとが、波長
λの同じ直線偏光の入射光に対して、Ｒ＋Ｒｖ＝ｍ×λ
／２（ｍ：整数）の関係を満たせばよい。ここでＲ
ｖは、Ｒ１≧Ｒｖ≧Ｒ２の関係を満たす。The range of voltage applied to the liquid crystal cell 110 is V 1
To V 2 (V 1 ≠ V 2 ), at which time the retardation value changes from R 1 to R 2 . In order to obtain an optical attenuator having a high extinction ratio at a specific voltage V within the above voltage range, the retardation value R v of the liquid crystal cell 110 generated at the voltage V and the retardation value R of the phase plate 120 are the wavelengths. For incident light of the same linear polarization of λ, R + R v = m × λ
It suffices to satisfy the relationship of / 2 (m: integer). Where R
v satisfies the relationship of R 1 ≧ R v ≧ R 2 .
【００２２】ここで、ｍが奇数の場合は偏光子における
透過直線偏光の偏光方向を液晶素子における入射直線偏
光の偏光方向と直交するように配置し、ｍが偶数の場合
は偏光子における透過直線偏光の偏光方向を液晶素子に
おける入射直線偏光の偏光方向と一致させれば、Ｖ１か
らＶ２までの範囲にある印加電圧Ｖで透過光量が最小と
なるため、高い消光比の光減衰器が実現する。Ｒ＋Ｒｖ
の絶対値が小さいほど消光比の波長依存性が少ないた
め、通常ｍ＝０が好ましいが、ｍ＝±１または±２とし
てもよい。Here, when m is an odd number, the polarization direction of the transmitted linearly polarized light in the polarizer is arranged so as to be orthogonal to the polarization direction of the incident linearly polarized light in the liquid crystal element, and when m is an even number, the transmission linearly polarized light in the polarizer is set. If the polarization direction of the polarized light is made to coincide with the polarization direction of the incident linearly polarized light in the liquid crystal element, the amount of transmitted light becomes the minimum at an applied voltage V in the range from V 1 to V 2, so that an optical attenuator with a high extinction ratio can To be realized. R + R v
Since the smaller the absolute value of is, the smaller the wavelength dependence of the extinction ratio is, m = 0 is usually preferable, but m = ± 1 or ± 2 may be set.
【００２３】したがって、液晶素子に用いられる液晶は
ネマティック液晶であり、電圧非印加時の液晶分子の配
向方向が透光性基板間で一定方向に揃った平行配向であ
り、また位相板はＲ＋Ｒｖ＝０の関係を満たし、かつ進
相軸方向が液晶層の遅相軸方向に対して４５°以内の角
度をなす液晶素子とすることが好ましい。Therefore, the liquid crystal used in the liquid crystal element is a nematic liquid crystal, and the alignment direction of the liquid crystal molecules when no voltage is applied is a parallel alignment in which the transparent substrates are aligned in a fixed direction, and the phase plate is R + R v. It is preferable that the liquid crystal element satisfy the relationship of = 0 and the fast axis direction forms an angle within 45 ° with the slow axis direction of the liquid crystal layer.
【００２４】また、図１では液晶層１と高分子液晶層２
との間に透光性基板６が介在しているが、透光性基板６
を用いないで透光性基板７上の高分子液晶層２に透明電
極４および配向膜を形成し、セル化後に液晶層を作製し
てもよい。Further, in FIG. 1, the liquid crystal layer 1 and the polymer liquid crystal layer 2 are shown.
The transparent substrate 6 is interposed between the transparent substrate 6 and the transparent substrate 6.
Alternatively, the transparent electrode 4 and the alignment film may be formed on the polymer liquid crystal layer 2 on the translucent substrate 7 without using, and the liquid crystal layer may be formed after the cell formation.
【００２５】図１では高分子液晶からなる位相板の構成
例を示したが、水晶などの複屈折結晶からなる位相板を
用いてもよい。その場合、図１の高分子液晶層２および
透光性基板６と７の代わりに透明電極４の形成された水
晶波長板を液晶セルの透光性基板６として用いることが
でき、液晶素子を小型化できる。また、図１では液晶セ
ルの電極として透明電極３と４を用いた構成を示した
が、一方の電極を金やアルミニウムなどの光反射性電極
とした反射型液晶セルとしてもよい。この場合、液晶層
を光が往復するため透過型に比べて液晶層の厚さを半分
にできるので、低駆動電圧化および高速応答化につなが
る。Although FIG. 1 shows a structural example of a phase plate made of polymer liquid crystal, a phase plate made of a birefringent crystal such as quartz may be used. In that case, instead of the polymer liquid crystal layer 2 and the transparent substrates 6 and 7 of FIG. 1, a crystal wave plate having a transparent electrode 4 formed thereon can be used as a transparent substrate 6 of a liquid crystal cell, and a liquid crystal element is formed. Can be miniaturized. Further, FIG. 1 shows a configuration in which the transparent electrodes 3 and 4 are used as the electrodes of the liquid crystal cell, but one of the electrodes may be a reflective liquid crystal cell using a light-reflecting electrode such as gold or aluminum. In this case, since the light travels back and forth through the liquid crystal layer, the thickness of the liquid crystal layer can be halved as compared with the transmissive type, which leads to lower driving voltage and faster response.
【００２６】使用される液晶はネマティック液晶に限定
されず、強誘電体液晶、反強誘電体液晶などでもよい。
また、液晶分子の配向も平行配向以外にねじれ配向、垂
直配向、ハイブリッド配向などでもよい。電圧印加に応
じて液晶層のリタデーション値が変化する液晶材料であ
ればよいし、また配向性の液晶であればよい。これらの
液晶の中で、ネマティック液晶を用いることは安定した
液晶配向が得られるため好ましい。The liquid crystal used is not limited to nematic liquid crystal, but may be ferroelectric liquid crystal, antiferroelectric liquid crystal or the like.
Further, the alignment of liquid crystal molecules may be twisted alignment, vertical alignment, hybrid alignment, etc. other than parallel alignment. Any liquid crystal material can be used as long as the retardation value of the liquid crystal layer changes in response to voltage application, and liquid crystal with orientation can be used. Among these liquid crystals, it is preferable to use a nematic liquid crystal because a stable liquid crystal alignment can be obtained.
【００２７】偏光子としては、特定の偏光方向を有する
直線偏光を透過しそれに直交する偏光方向を有する直線
偏光を吸収する、例えば金属微粒子をガラス中に分散さ
せた偏光性ガラスなどがある。しかし、液晶素子と一体
化して偏光性ガラスを用いる場合光吸収に伴い液晶素子
の温度が上昇し、光減衰率が変化する問題があった。Examples of the polarizer include a polarizing glass which transmits linearly polarized light having a specific polarization direction and absorbs linearly polarized light having a polarization direction orthogonal thereto, for example, polarizing glass in which fine metal particles are dispersed in glass. However, when the polarizing glass is used integrally with the liquid crystal element, there is a problem that the temperature of the liquid crystal element rises due to light absorption and the light attenuation rate changes.
【００２８】上記の光吸収に伴う温度変化を低減するた
め、偏光回折型の偏光子を用いることが好ましい。本発
明の光減衰器に用いられる偏光回折型の偏光子２００の
構成例を図３に示す。透光性基板１２上に形成された常
光屈折率ｎｏ（ＰＬＣ）と異常光屈折率ｎｅ（ＰＬＣ）
（ｎｏ（ＰＬＣ）＜ｎｅ（ＰＬＣ））の高分子液晶層１
０を、フォトエッチングの技術により断面形状が矩形状
の回折格子に加工する。そして、格子の凹部に常光屈折
率ｎｏ（ＰＬＣ）とほぼ等しい屈折率ｎｓの均質屈折率
透明材料１１を充填して透光性基板１２と１３とで挟み
偏光回折型の偏光子２００を形成する。In order to reduce the temperature change due to the above light absorption, it is preferable to use a polarization diffraction type polarizer. FIG. 3 shows a configuration example of the polarization diffraction type polarizer 200 used in the optical attenuator of the present invention. Ordinary light refractive index n o (PLC) and extraordinary light refractive index n e (PLC) formed on the transparent substrate 12.
Polymer liquid crystal layer 1 of (n o (PLC) <n e (PLC))
0 is processed into a diffraction grating having a rectangular cross section by a photo-etching technique. Then, the concave portion of the grating is filled with a homogeneous refractive index transparent material 11 having a refractive index n s that is substantially equal to the ordinary light refractive index n o (PLC) and sandwiched between the transparent substrates 12 and 13 to form a polarization diffraction type polarizer 200. Form.
【００２９】上記の偏光回折型の偏光子に入射する常光
偏光は回折されることなく透直進過し、異常光偏光は回
折される。したがって、光出射側にレンズなどの集光素
子を設けると、直進透過光は一つの集光点に集光し回折
光は別の集光点に集光するため、透過光と回折光とを空
間的に分離できる。したがって、直進透過光のみ取り出
せば高い消光比の偏光子となる。The ordinary light polarization incident on the above-mentioned polarization diffraction type polarizer goes straight through without being diffracted, and the extraordinary light polarization is diffracted. Therefore, if a light-collecting element such as a lens is provided on the light exit side, the straight transmitted light is condensed at one condensing point and the diffracted light is condensed at another condensing point. Can be spatially separated. Therefore, if only the straight transmitted light is taken out, a polarizer having a high extinction ratio can be obtained.
【００３０】したがって、偏光子は、第１の直線偏光の
入射光を直進透過し、第１の直線偏光の偏光方向と直交
する偏光方向を有する第２の直線偏光を回折する偏光回
折型の偏光子である上記の光減衰器とすることが好まし
い。Therefore, the polarizer linearly transmits the incident light of the first linearly polarized light, and diffracts the second linearly polarized light having a polarization direction orthogonal to the polarization direction of the first linearly polarized light, which is a polarization diffraction type polarization. The above-mentioned optical attenuator which is a child is preferable.
【００３１】上記の偏光回折型の偏光子２００を液晶素
子１００と一体化した本発明の光減衰器３００の構成例
を図４に示す。ここでは液晶素子１００に直線偏光が入
射する光出射側に偏光回折型の偏光子２００が配置され
た例を示すが、入射光のうち特定偏光方向の直線偏光成
分のみを液晶素子１００に入射する場合は、光入射側に
も偏光回折型の偏光子を配置すればよい。FIG. 4 shows a structural example of the optical attenuator 300 of the present invention in which the above-mentioned polarization diffraction type polarizer 200 is integrated with the liquid crystal element 100. Here, an example in which a polarization diffraction type polarizer 200 is arranged on the light exit side where linearly polarized light is incident on the liquid crystal element 100 is shown. However, only the linearly polarized light component of a specific polarization direction of incident light is incident on the liquid crystal element 100. In this case, a polarization diffraction type polarizer may be arranged also on the light incident side.
【００３２】このように、液晶素子の光入射側または光
出射側の少なくとも一方の側に偏光回折型の偏光子を配
置して、一体に構成することにより素子の小型化および
安定した性能が得られるため好ましい。As described above, by arranging the polarization diffraction type polarizer on at least one of the light incident side and the light emitting side of the liquid crystal element and integrally forming them, the element can be downsized and stable performance can be obtained. It is preferable because it is possible.
【００３３】[0033]
【実施例】本例の液晶素子１００について、図１を用い
て説明する。常光屈折率ｎｏ（ＬＣ）＝１．５０および
異常光屈折率ｎｅ（ＬＣ）＝１．６６のネマティック液
晶を、透明電極３、４が片面に形成された透光性基板
５、６に挟持し、液晶層１の厚さｄ（ＬＣ）を５μｍと
した液晶セル１１０を作製した。液晶層１の遅相軸方向
は、図２に示すＹ軸方向に対して４５度で基板に対して
平行とした。EXAMPLE A liquid crystal element 100 of this example will be described with reference to FIG. A nematic liquid crystal having an ordinary light refractive index n o (LC) = 1.50 and an extraordinary light refractive index n e (LC) = 1.66 is applied to the translucent substrates 5 and 6 having the transparent electrodes 3 and 4 formed on one surface. A liquid crystal cell 110 was produced in which the liquid crystal layer 1 was sandwiched and the thickness d (LC) of the liquid crystal layer 1 was 5 μm. The slow axis direction of the liquid crystal layer 1 was 45 degrees with respect to the Y-axis direction shown in FIG. 2 and was parallel to the substrate.
【００３４】透明電極３、４に電圧を印加しない状態で
は、波長１．５５μｍの光に対する液晶セル１１０のリ
タデーション値は０．８μｍ（Ｒ１）であり、Ｙ軸方向
に偏光方向を有する直線偏光が、液晶セル１１０に入射
し出射したとき直線偏光の偏光方向はＸ軸方向となっ
た。また、電圧振幅５Ｖの矩形波の交流電圧を印加した
状態では、液晶セル１１０のリタデーション値Ｒｖは
０．１２８μｍ（Ｒ２）であった。When no voltage is applied to the transparent electrodes 3 and 4, the retardation value of the liquid crystal cell 110 for light having a wavelength of 1.55 μm is 0.8 μm (R 1 ), and linearly polarized light having a polarization direction in the Y-axis direction. However, the polarization direction of the linearly polarized light was the X-axis direction when entering and exiting the liquid crystal cell 110. Further, the retardation value R v of the liquid crystal cell 110 was 0.128 μm (R 2 ) when a rectangular wave AC voltage having a voltage amplitude of 5 V was applied.
【００３５】さらに、透光性基板６、７に挟持されてい
る高分子液晶層２は、常光屈折率ｎ ｏ（ＰＬＣ）＝１．
５５および異常光屈折率ｎｅ（ＰＬＣ）＝１．５９で厚
さｄ（ＰＬＣ）を３．２μｍとし、位相板１２０を構成
し、この位相板１２０と液晶セル１１０によって液晶素
子１００を作製した。ここで、位相板１２０の進相軸方
向を液晶層１の遅相軸方向と一致させると、すなわちθ
＝０とすると、高分子液晶層２からなる位相板１２０の
リタデーション値Ｒは−０．１２８μｍとなるため、印
加電圧５Ｖでの液晶層１に存在するリタデーション値
０．１２８μｍを相殺した。すなわちｍ×λ＝０でｍ＝
０に対応する。Further, it is sandwiched between the transparent substrates 6 and 7.
The polymer liquid crystal layer 2 having a normal refractive index n o(PLC) = 1.
55 and extraordinary light refractive index ne(PLC) = 1.59 and thick
The phase plate 120 is configured by setting the height d (PLC) to 3.2 μm.
The phase plate 120 and the liquid crystal cell 110 are used to
A child 100 was produced. Here, the fast axis of the phase plate 120
If the direction is aligned with the slow axis direction of the liquid crystal layer 1, that is, θ
= 0, the phase plate 120 composed of the polymer liquid crystal layer 2
Since the retardation value R is -0.128 μm,
Retardation value existing in the liquid crystal layer 1 at an applied voltage of 5V
0.128 μm was offset. That is, m × λ = 0 and m =
Corresponds to 0.
【００３６】さらに、図３に示すように、常光屈折率ｎ
ｏ（ＰＬＣ）＝１．５５および異常光屈折率ｎｅ（ＰＬ
Ｃ）＝１．７０で厚さ５．２μｍの高分子液晶を用いて
格子ピッチ１０μｍの回折格子１０を作製した。その
後、屈折率１．５５の均質屈折率透明材料１１で格子の
凹部を埋め、これらをガラス基板からなる透光性基板１
２、１３で狭持して偏光回折型の偏光子２００を作製し
た。次に、図４に示すように、偏光子２００を液晶素子
１００の光出射面側に接着固定して電圧可変型の光減衰
器３００とした。ここで、偏光子２００の回折光の偏光
方向をＹ軸方向としている。Further, as shown in FIG. 3, the ordinary refractive index n
o (PLC) = 1.55 and extraordinary light refractive index n e (PL
A diffraction grating 10 having a grating pitch of 10 μm was manufactured using a polymer liquid crystal having a thickness of 5.2 μm with C) = 1.70. After that, the concave portions of the grating are filled with the transparent material 11 having a uniform refractive index of 1.55, and these are filled with the transparent substrate 1 made of a glass substrate.
A polarizing diffraction type polarizer 200 was produced by sandwiching the polarizing element 200 with the polarizing element 200. Next, as shown in FIG. 4, the polarizer 200 was adhesively fixed to the light emitting surface side of the liquid crystal element 100 to obtain a voltage variable type optical attenuator 300. Here, the polarization direction of the diffracted light of the polarizer 200 is the Y-axis direction.
【００３７】このようにして作製した光減衰器３００
に、波長１．５５μｍでＹ軸方向に偏光方向を有する直
線偏光の平行光を入射し、出射光を集光レンズにより光
ファイバーに集光した。Optical attenuator 300 manufactured in this way
Then, linearly polarized parallel light having a wavelength of 1.55 μm and a polarization direction in the Y-axis direction was made incident, and the emitted light was condensed on an optical fiber by a condenser lens.
【００３８】光減衰器の液晶層への印加電圧振幅を０か
ら５Ｖまで変化させたとき、光ファイバー伝送後の光強
度Ｉ（Ｖ）における光強度比Ｉ（Ｖ）／Ｉ（０）で規定
される消光比の変化の一例を図５の○で示す。図５で
は、縦軸の数値が小さいほど（下に行くほど）、消光比
が大きい。また、比較例として、位相板のない従来構成
の光減衰器とした場合の消光比の変化を□で示した。When the amplitude of the voltage applied to the liquid crystal layer of the optical attenuator is changed from 0 to 5 V, it is defined by the light intensity ratio I (V) / I (0) in the light intensity I (V) after the optical fiber transmission. An example of the change in extinction ratio is shown by a circle in FIG. In FIG. 5, the smaller the numerical value on the vertical axis (lower), the larger the extinction ratio. As a comparative example, the change in extinction ratio in the case of a conventional optical attenuator without a phase plate is shown by □.
【００３９】位相板を用いない従来構成の液晶素子では
最大−１２ｄＢの消光比であったが、位相板を用いた本
例の構成では−４０ｄＢの高い消光比が得られた。The maximum extinction ratio of -12 dB was obtained in the conventional liquid crystal device without the phase plate, but a high extinction ratio of -40 dB was obtained in the structure of this example using the phase plate.
【００４０】[0040]
【発明の効果】以上説明したように、本発明の液晶素子
を用いることにより、印加電圧の増加とともに緩やかに
出射光量が減少し、５Ｖ程度の低電圧でも高い消光比を
有する電圧可変型の光減衰器が実現できる。As described above, by using the liquid crystal element of the present invention, the amount of emitted light gradually decreases with an increase in the applied voltage, and the voltage variable type light having a high extinction ratio even at a low voltage of about 5V is obtained. Attenuator can be realized.
【００４１】さらに、光吸収のほとんどない偏光回折型
の偏光子を液晶素子と一体化した本発明の光減衰器では
高強度の光が入射しても液晶層の温度上昇が少ないた
め、安定した消光比が得られる。Further, in the optical attenuator of the present invention in which a polarization diffraction type polarizer which hardly absorbs light is integrated with a liquid crystal element, the temperature rise of the liquid crystal layer is small even when high intensity light is incident, so that it is stable. An extinction ratio is obtained.
【図１】本発明の液晶素子の構成例を示す側面図。FIG. 1 is a side view showing a configuration example of a liquid crystal element of the present invention.
【図２】本発明の液晶素子の遅相軸方向と位相板の進相
軸方向との関係を示す平面図。FIG. 2 is a plan view showing the relationship between the slow axis direction of the liquid crystal element of the present invention and the fast axis direction of the phase plate.
【図３】本発明の光減衰器に用いられる偏光回折型の偏
光子の構成例を示す側面図。FIG. 3 is a side view showing a configuration example of a polarization diffraction type polarizer used in the optical attenuator of the present invention.
【図４】本発明の液晶素子に偏光回折型の偏光子が一体
化された光減衰器の構成例を示す側面図。FIG. 4 is a side view showing a configuration example of an optical attenuator in which a polarization diffraction type polarizer is integrated with the liquid crystal element of the present invention.
【図５】本発明の光減衰器と従来の光減衰器において、
液晶セル印加電圧に対する消光比の関係を示すグラフ。FIG. 5 shows an optical attenuator of the present invention and a conventional optical attenuator,
The graph which shows the relationship of the extinction ratio with respect to the liquid crystal cell applied voltage.
【図６】従来の光減衰器の構成例を示す側面図。FIG. 6 is a side view showing a configuration example of a conventional optical attenuator.
１：液晶層 ２：高分子液晶層 ３、４：透明電極 ５、６、７、１２、１３：透光性基板 ８：シール材 ９：交流電源 １０：偏光性回折格子 １１：均質屈折率透明材料 １２：偏光子 １００：液晶素子 １１０：液晶セル １２０：位相板 ２００：偏光回折型の偏光子 ３００：光減衰器 1: Liquid crystal layer 2: Polymer liquid crystal layer 3,4: Transparent electrode 5, 6, 7, 12, 13: translucent substrate 8: Seal material 9: AC power supply 10: Polarizing diffraction grating 11: Transparent material with homogeneous refractive index 12: Polarizer 100: Liquid crystal element 110: Liquid crystal cell 120: Phase plate 200: Polarization diffraction type polarizer 300: Optical attenuator
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 2H049 BA02 BA06 BA42 BA45 BB03 BC22 2H079 AA02 AA12 BA01 CA04 DA08 EB17 HA13 KA08 KA17 2H088 EA32 EA44 HA15 KA07 MA02 MA20 2H091 FA08X FA08Z FA11X FA11Z FD06 FD10 GA03 GA06 HA07 LA17 MA10 ─────────────────────────────────────────────────── ─── Continued front page F-term (reference) 2H049 BA02 BA06 BA42 BA45 BB03 BC22 2H079 AA02 AA12 BA01 CA04 DA08 EB17 HA13 KA08 KA17 2H088 EA32 EA44 HA15 KA07 MA02 MA20 2H091 FA08X FA08Z FA11X FA11Z FD06 FD10 GA03 GA06 HA07 LA17 MA10
Claims (4)
た液晶セルであり、かつ電極間に印加する電圧をＶ１か
らＶ２（Ｖ１≠Ｖ２）まで変化させたとき、液晶セルへ
入射され透過される波長λの直線偏光に対するリタデー
ション値がＲ１からＲ２（Ｒ １＞Ｒ２＞０）まで変化す
る液晶セルと、 波長λの直線偏光に対するリタデーション値ＲがＲ１≧
Ｒｖ≧Ｒ２の関係にあるＲｖと、Ｒ＋Ｒｖ＝ｍ×λ
（ｍ：整数）の関係を満たす位相板と、 を備えることを特徴とする液晶素子。1. A liquid crystal layer is sandwiched between transparent substrates with electrodes.
Liquid crystal cell, and the voltage applied between the electrodes is V1Or
Et VTwo(V1≠ VTwo) To the liquid crystal cell
Ritaday for linearly polarized light of wavelength λ that is incident and transmitted
Value is R1To RTwo(R 1> RTwoChange to> 0)
Liquid crystal cell, Retardation value R for linearly polarized light of wavelength λ is R1≧
Rv≧ RTwoR in the relationshipvAnd R + Rv= M × λ
A phase plate satisfying the relationship of (m: integer), A liquid crystal element comprising:
ック液晶であり、電圧非印加時の液晶分子の配向方向が
透光性基板間で一定方向に揃った平行配向であり、また
前記位相板はＲ＋Ｒｖ＝０の関係を満たし、かつ進相軸
方向が液晶層の遅相軸方向に対して４５°以内の角度を
なす請求項１記載の液晶素子。2. The liquid crystal used in the liquid crystal element is a nematic liquid crystal, and the alignment direction of liquid crystal molecules when no voltage is applied is a parallel alignment in which the transparent substrates are aligned in a fixed direction, and the phase plate is The liquid crystal element according to claim 1, wherein the relationship of R + R v = 0 is satisfied, and the fast axis direction forms an angle within 45 ° with the slow axis direction of the liquid crystal layer.
側または光出射側の少なくとも一方の側に偏光子がさら
に配置され、液晶層への印加電圧の増加に伴い出射光強
度が減少することを特徴とする光減衰器。3. A polarizer is further disposed on at least one of the light incident side and the light emitting side of the liquid crystal element according to claim 1, and the intensity of emitted light decreases as the voltage applied to the liquid crystal layer increases. An optical attenuator characterized by:
し、第１の直線偏光の偏光方向と直交する偏光方向を有
する第２の直線偏光を回折する偏光回折型の偏光子であ
る請求項３記載の光減衰器。4. The polarization diffractive polarizer, wherein the polarizer linearly transmits the first linearly polarized light and diffracts a second linearly polarized light having a polarization direction orthogonal to the polarization direction of the first linearly polarized light. An optical attenuator according to claim 3.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001256301A JP5150992B2 (en) | 2001-08-27 | 2001-08-27 | Liquid crystal device and optical attenuator |
| EP02760728A EP1420275B1 (en) | 2001-08-24 | 2002-08-23 | Isolator and optical attenuator |
| PCT/JP2002/008517 WO2003019247A1 (en) | 2001-08-24 | 2002-08-23 | Multi-layer diffraction type polarizer and liquid crystal element |
| US10/784,714 US7079202B2 (en) | 2001-08-24 | 2004-02-24 | Multi-layer diffraction type polarizer and liquid crystal element |
| US11/313,694 US7764354B2 (en) | 2001-08-24 | 2005-12-22 | Multi-layer diffraction type polarizer and liquid crystal element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001256301A JP5150992B2 (en) | 2001-08-27 | 2001-08-27 | Liquid crystal device and optical attenuator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2003066450A true JP2003066450A (en) | 2003-03-05 |
| JP5150992B2 JP5150992B2 (en) | 2013-02-27 |
Family
ID=19084130
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001256301A Expired - Fee Related JP5150992B2 (en) | 2001-08-24 | 2001-08-27 | Liquid crystal device and optical attenuator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5150992B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003295152A (en) * | 2002-04-04 | 2003-10-15 | Citizen Watch Co Ltd | Liquid crystal optical switch |
| JP2006154492A (en) * | 2004-11-30 | 2006-06-15 | Asahi Glass Co Ltd | Liquid crystal element and optical attenuator |
| JP2007225905A (en) * | 2006-02-23 | 2007-09-06 | Asahi Glass Co Ltd | Optical isolator and bidirectional optical transmitting/receiving apparatus |
| JP2007333945A (en) * | 2006-06-14 | 2007-12-27 | Asahi Glass Co Ltd | Liquid crystal element, light source device and optical head device |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07333617A (en) * | 1994-06-03 | 1995-12-22 | Toshiba Corp | Liquid crystal display element |
| JPH0933917A (en) * | 1995-07-19 | 1997-02-07 | Casio Comput Co Ltd | Color liquid crystal display element |
| JP2000330114A (en) * | 1999-05-24 | 2000-11-30 | Victor Co Of Japan Ltd | Direct view display |
| JP2001125143A (en) * | 1999-10-28 | 2001-05-11 | Sharp Corp | Reflection type liquid crystal display device |
-
2001
- 2001-08-27 JP JP2001256301A patent/JP5150992B2/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH07333617A (en) * | 1994-06-03 | 1995-12-22 | Toshiba Corp | Liquid crystal display element |
| JPH0933917A (en) * | 1995-07-19 | 1997-02-07 | Casio Comput Co Ltd | Color liquid crystal display element |
| JP2000330114A (en) * | 1999-05-24 | 2000-11-30 | Victor Co Of Japan Ltd | Direct view display |
| JP2001125143A (en) * | 1999-10-28 | 2001-05-11 | Sharp Corp | Reflection type liquid crystal display device |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003295152A (en) * | 2002-04-04 | 2003-10-15 | Citizen Watch Co Ltd | Liquid crystal optical switch |
| JP2006154492A (en) * | 2004-11-30 | 2006-06-15 | Asahi Glass Co Ltd | Liquid crystal element and optical attenuator |
| JP2007225905A (en) * | 2006-02-23 | 2007-09-06 | Asahi Glass Co Ltd | Optical isolator and bidirectional optical transmitting/receiving apparatus |
| JP2007333945A (en) * | 2006-06-14 | 2007-12-27 | Asahi Glass Co Ltd | Liquid crystal element, light source device and optical head device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP5150992B2 (en) | 2013-02-27 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7079202B2 (en) | Multi-layer diffraction type polarizer and liquid crystal element | |
| KR101098202B1 (en) | Polarized diffractive filter and layered polarized diffractive filter | |
| US20200089078A1 (en) | Compact liquid crystal beam steering devices including multiple polarization gratings | |
| KR100724905B1 (en) | Optical film, polarizer and display device | |
| JP2009294604A (en) | Optical modulation liquid crystal element and variable optical attenuator | |
| JP4792679B2 (en) | Isolator and variable voltage attenuator | |
| JP4106981B2 (en) | Optical attenuator | |
| JPH0534656A (en) | Focal length variable liquid crystal lens | |
| KR100284647B1 (en) | Nematic liquid crystal Fabry-Perot wavelength tunable filter device | |
| JP2005003758A (en) | Reflective optical modulator and variable optical attenuator | |
| JP5150992B2 (en) | Liquid crystal device and optical attenuator | |
| US8107152B2 (en) | Electro-optical tunable birefringent filter | |
| KR940006340B1 (en) | Linear polarizer | |
| JPH06301006A (en) | Color liquid crystal display device | |
| JP2803181B2 (en) | Birefringent diffraction grating polarizer | |
| JPH05297339A (en) | Liquid crystal light refracting element | |
| JPH04140714A (en) | Variable wavelength filter module | |
| JP2004325790A (en) | Optical modulation element and optical attenuator | |
| JP4168767B2 (en) | Liquid crystal device and optical attenuator | |
| JP2004347784A (en) | Reflection type optical element | |
| JPS61203402A (en) | Functional optical element | |
| JPH11125801A (en) | Wavelength selection filter | |
| JPH04240804A (en) | Polarizing element | |
| JP2006154492A (en) | Liquid crystal element and optical attenuator | |
| JPS587118A (en) | Spatial filter |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20080616 |
|
| RD03 | Notification of appointment of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7423 Effective date: 20110407 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20110823 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20111014 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20120306 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20120426 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20121106 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20121119 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20151214 Year of fee payment: 3 |
|
| R151 | Written notification of patent or utility model registration |
Ref document number: 5150992 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R151 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20151214 Year of fee payment: 3 |
|
| S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
| R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
| R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
| LAPS | Cancellation because of no payment of annual fees |