JPS6211823A - Polarized light converter - Google Patents

Abstract

PURPOSE:To obtain efficiently a linearly polarized light by separating light of a non- polarized light from a light emitting diode, into P and S polarized lights by a polarized light prism, making a liquid crystal pass through separately and rotating a plane of polarization, and synthesizing them after the planes of polarization have been made uniform. CONSTITUTION:An emitted light of a non-polarized light from a light emitting diode LED 7 is fucused by a rod lens 6, and made incident on a polarized light prism 2. The incident light is divided into a wave P for traveling straight on and a wave S whose direction is varied by 90 deg. by a place of polarization 2'. The wave P and the wave S pass through a liquid crystal cell 4b, and a liquid crystal cell 4a by being reflected in the prism, respectively. By a changeover switch 9, a voltage from a power source 8 is impressed to both faces of one liquid crystal. The liquid crystal to wich the voltage has been impressed turns the plane of polarization by 90 deg., and the wave P and the wave S become the wave S and the wave P, respectively. After the plane of polarization has been made uniform to a desired linearly polarized light, they are synthesized by a synthesizing prism 5, and an emitted light O is obtained. In this way, a P or S polarized light is obtained, and also by switching the switch 9, the P/S mutual conversion is executed instantaneously.

Description

【発明の詳細な説明】 〔麓東上の利用分野〕 この発＃！ＡはＬＢＤを光源とする各種の光測定器、光
装置などに用いら扛る偏光変換器に関するものである。[Detailed description of the invention] [Field of application of Rokutojo] This release #! A relates to a polarization converter used in various optical measuring instruments, optical devices, etc. that use an LBD as a light source.

（す 〔従来技術〕 まず、従来のこの稙の偏光変換器について、第２図（ａ
）、（ｂ）を用いて説明する。図中、（１）はグレーテ
ィング、＋２１ｉＪ偏光プリズムである。ＬＥＤからの
発光は、特定の偏光をもたない　いわゆる無偏光であり
、直線偏光であるＰ偏光およびｓｆｉ！光が混然とした
状ＷＡＫなっている。したがって、　　Ｌｉ！ｉＤを発
光源とし、直線偏光を用いて信号処理を行なう各檀光装
置などにおいては８一般に、所要の直線偏光な得るため
に、光路に偏光子（ｐｏｉａｒｉ−ｔｅｒ）と盲わｎる
素子奪挿入する。第２図（ａ）のグレーティング（１）
は光の透過率の優ｆ′Ｌｆｃ２！！板上に。(Prior art) First, let's talk about the conventional polarization converter of this type as shown in Fig. 2 (a).
) and (b). In the figure, (1) is a grating and a +21iJ polarizing prism. The light emitted from the LED does not have a specific polarization, so-called non-polarized light, and there is P-polarized light, which is linearly polarized light, and sfi! The light looks like WAK. Therefore, Li! In various optical devices that use iD as a light source and perform signal processing using linearly polarized light,8 generally, in order to obtain the required linearly polarized light, a polarizer (poiali-ter) and a blind element are installed in the optical path. insert. Grating (1) in Figure 2(a)
is the light transmittance f'Lfc2! ! on the board.

光の波長より細かい間隔で金輌ストリップなどを蒸着し
たものであり、ｚ軸方向に無偏光を入射させｆｃ場合、
その透過光Ｆｉｓ偏光となり、Ｐ偏光成分は反射さｎて
２軸の負方向に進行する。第２図（ｂ）の偏光プリズム
（２１ａ　＋　ガラス母材間に、偏光膜を糾め４５°に
蒸着したものであり、２一方向に無偏光を入射させた場
合、その透過光にＰ偏光となり、８偏光膜分は反射さｎ
てＹ軸方向に進行する。Gold strips are deposited at intervals finer than the wavelength of light, and when unpolarized light is incident in the z-axis direction,
The transmitted light becomes Fis polarized light, and the P polarized light component is reflected and travels in the negative direction of the two axes. The polarizing prism shown in Fig. 2(b) (21a + a polarizing film is vapor-deposited at an angle of 45 degrees between the glass base material), and when unpolarized light is incident in one direction, the transmitted light has P-polarized light. Therefore, 8 polarizing films are reflected n
and move in the Y-axis direction.

〔発明が解決しようとする問題点Ｊ　　　　・上述した
ような従来の偏光変換器では、無偏光ｙｐ偏光成分とＳ
偏光成分に弁別するものの、一方の成分はすててしまう
ため、変換の効率は少なくても３（ＬＢ以上となり効率
的でなかった。また利用できるものも一方の偏光成分の
みだけであり応用面で不都合であった。[Problem to be solved by the invention J - In the conventional polarization converter as described above, the unpolarized yp polarized component and the S
Although it differentiates into polarized light components, one component is discarded, so the conversion efficiency is at least 3 (LB or more), which is not efficient.In addition, only one polarized component can be used, which is not practical. It was inconvenient.

この発明にかかる問題点を解決するためになさｆたもの
であり、少ない損失で無偏光から直線偏光ＶＣ変換する
ことを目的とする。This invention was made in order to solve the problems associated with the present invention, and its purpose is to perform VC conversion from unpolarized light to linearly polarized light with little loss.

〔問題点を解決するための手段〕[Means for solving problems]

この発明による偏光変換器は、液晶に電圧を印加するこ
とにより、偏光を回転させることのできる点に注目し、
偏光プリズムで弁別した異なる直線偏光成分を、液晶セ
ルでそろえるよう構成したものである。The polarization converter according to the present invention focuses on the fact that polarization can be rotated by applying a voltage to the liquid crystal.
It is constructed so that different linearly polarized light components discriminated by a polarizing prism are aligned in a liquid crystal cell.

〔作用〕[Effect]

この発明においてに、２枚の歌晶セルへの印加電圧を切
替えることにより、無偏光をＰもしくはＳ偏光成分のみ
にに換することができる。In this invention, by switching the voltage applied to the two song crystal cells, unpolarized light can be converted into only P or S polarized light components.

〔実施例〕〔Example〕

第１図はこの発明の偏光変換器の一実施例であ９５図中
、（２）は偏光プリズム、（３）に偏光変換器。FIG. 1 shows an embodiment of the polarization converter of the present invention. In FIG. 95, (2) is a polarization prism, and (3) is a polarization converter.

（４１Ｖｉ液晶セル、（５Ｈｆｆ合成プリズム、（６）
はロッドレンズ８（７）はＬＫＤ、＋８１６′ぼ諒、（
９）は切替スイッチである。偏光変換器（３１Ｕ、　　
ＬＥＤ（７１，ロッドレンズ＋６１．１％元プリズム＋
２１．２枚の液晶セル（４ａ）　。(41Vi liquid crystal cell, (5Hff synthesis prism, (6)
The rod lens 8 (7) is LKD, +816', (
9) is a changeover switch. Polarization converter (31U,
LED (71, rod lens + 61.1% original prism +
21. Two liquid crystal cells (4a).

（４ｂ）とこルに′電圧を印加する電源（８）、切替ス
イッチ（９）および合成プリズム（５）から構成さ扛、
ＬＥＤ（７）からの無偏光なＰ偏光もしくはＢ’１Ｍ元
の＠線偏光に変換する。変換の過程は以下に示す通りで
ある。一般にＬ　Ｅ　Ｄ　（７１からの発光に拡散さｎ
るため、ロッドレンズ（６）を用いて平行光とし、偏光
プリズム（２）の偏光膜ＶＣ入射させる。入射した無偏
光に偏光プリズム（２）でＰＩＩ４元成分とＳ偏光成分
に弁別さ扛るが、透過光であるＰ開光成分は液晶セル（
４ｂ）を経て１合成プリズム（５）内を通過し、空間に
放射する。−力１反射光であ４＋ｓ偏光偏光は。(4b) A prism consisting of a power supply (8) for applying a voltage thereto, a changeover switch (9), and a combining prism (5);
It converts into unpolarized P polarized light from the LED (7) or B'1M original @ line polarized light. The conversion process is shown below. In general, the light emitted from L E D (71 is diffused)
Therefore, the parallel light is made into parallel light using a rod lens (6), and is made incident on the polarizing film VC of the polarizing prism (2). The polarizing prism (2) separates the incident unpolarized light into a PII quaternary component and an S-polarized component, but the transmitted light, the P-polarized component, passes through the liquid crystal cell (
4b), passes through one synthesis prism (5), and radiates into space. -The power of 1 reflected light is 4+s polarized light.

偏光プリズム（２）の一部である直角プリズム部で光路
を変え、液晶セル（４ａ）を蛙で合成７゛リズムｆ５）
内を通過し、空間に放射する　すなわち１合成プリズム
（５）から出射する時点において　光ビームは同一直線
偏光として合成さｎる。Change the optical path with the right angle prism part that is part of the polarizing prism (2), and synthesize the liquid crystal cell (4a) with a frog 7゛rhythm f5)
The light beams are combined into the same linearly polarized light at the time they pass through the interior and radiate into space, that is, when they exit from the combining prism (5).

第３図に液晶セル（４）の動作を説明するための図であ
り５図中、（８）に電源、（９）はスイッチである。FIG. 3 is a diagram for explaining the operation of the liquid crystal cell (4), and in FIG. 5, (8) is a power supply, and (9) is a switch.

液晶セルｆ４１にも各種あるが、ここではＴＮ（ＴＷｉ
−ｓｔｅｄ　Ｎθｍａｔｉｃ）タイプのもので説明を行
なう液晶セル（４）は２枚のガラス板の間に液晶を封じ
込めたものであり、その両面に電源（８）からの電圧な
印加す扛ば、液晶の分子配列が変化し、偏光が回転する
。ＴＮタイプの場合２重圧を印加しない時すなわちスイ
ッチ（９）がＯＦＦの時１日偏光を入射させ江ば、透過
光はＰ偏光に変換さｆ、電圧を印加した時１すなわちス
イッチ（９）がＯ’Ｈの時、Ｓ偏光を入射させ扛ば、透
過光に８偏光のままになる。There are various types of liquid crystal cell f41, but here we will use TN (TWi).
The liquid crystal cell (4), which will be explained as a (sted Nθmatic) type, has liquid crystal sealed between two glass plates, and when a voltage from a power source (8) is applied to both sides, the liquid crystal molecules The alignment changes and the polarization rotates. In the case of the TN type, when no double pressure is applied, that is, when switch (9) is OFF, if polarized light is input for one day, the transmitted light is converted to P-polarized light, and when voltage is applied, 1, that is, switch (9) is turned off. When S-polarized light is incident at O'H, the transmitted light remains as 8-polarized light.

つまり、電圧の０Ｎ１０ＦＦで直線偏光なＰから８へま
たに、ＳからＰへ変換することがセきる。　□再び第１
図にもどり、２枚の艙昂セル（４ａ）（４ｂ）への電圧
の印加について説明する。電源（８）の一端は２枚の液
晶セル（４ａ）、　（４ｂ）に接続さ几、もう一端は切
替スイッチ（９）の中点に接続される。したがって、切
替スイッチ（９）がイ側にある場合、′ｅ、晶セル（４
１））ＶＣ電圧が印加さ扛、液晶セル（４ａ）には印加
さ扛ない。同（求Ｋ　　切替スイッチ（９）が口側にあ
る場什、液晶セル（４ａ）ＶＣ’市圧電圧加さ扛、液晶
セル（４ｂ）には印加さｎなくなる。すなわち、切替ス
イッチ（９）がイ側の場合、液晶セル（４ａ）をス出る
尤の偏光が８偏光からＰ偏光に変換さ扛、液晶セル（４
ｂ）を通る穴の偏光はＰ１涌光のま筐通過する。That is, it is possible to convert linearly polarized light P to 8 and S to P with a voltage of 0N10FF. □First again
Returning to the figure, the application of voltage to the two overflow cells (4a) (4b) will be explained. One end of the power source (8) is connected to the two liquid crystal cells (4a) and (4b), and the other end is connected to the midpoint of the changeover switch (9). Therefore, when the selector switch (9) is on the A side, 'e', the crystal cell (4
1)) VC voltage is applied, but not applied to the liquid crystal cell (4a). When the changeover switch (9) is on the opening side, the liquid crystal cell (4a) VC' voltage is applied and no voltage is applied to the liquid crystal cell (4b).In other words, the changeover switch (9) When the polarization is on the A side, the polarized light exiting the liquid crystal cell (4a) is converted from 8-polarized light to P-polarized light.
The polarized light of the hole passing through b) passes through the P1 box.

したがって０合成さｎ−た光にＰ偏光となる。同様に、
切替スイッチ（９）が口側の場合、液晶セル（４ａ）を
通る元の偏光にＳ偏光のまま通過し、７Ｗ晶セル（４ｂ
）を通る元の偏光はＰ偏光からＳ偏光ＶＣ変換さＡ、し
たがって１合成さｎたＩｔＳはＳ偏光となる。Therefore, the 0-combined light becomes P-polarized light. Similarly,
When the changeover switch (9) is on the opening side, the original polarized light passing through the liquid crystal cell (4a) passes through the S-polarized light as it is, and the 7W crystal cell (4b)
) is converted from P-polarized light to S-polarized VC A, so the 1-synthesized ItS becomes S-polarized light.

〔発明の効果〕〔Effect of the invention〕

以上説明したように、この発明の偏光変換器によｎば、
ＬＥＤからの無偏光を偏光プリズムで弁別し、弁別さ扛
たＰ偏光もしくはＳ偏光を各々専用の成品セルに通過さ
せ１合成プリズムで合成するよう構成したため、低損失
でＰ偏光もしくはＳ偏光の直線偏光を傅ら扛るとともＶ
Ｃ１液晶セルに印加する電圧を切替えることにより８瞬
時Ｖ（偏光を切り替えることができる。As explained above, according to the polarization converter of the present invention,
The unpolarized light from the LED is discriminated by a polarizing prism, and the discriminated P-polarized light or S-polarized light is passed through a dedicated product cell and combined by one combining prism, so it is possible to generate P-polarized light or S-polarized light in a straight line with low loss. Tomo V
By switching the voltage applied to the C1 liquid crystal cell, the polarization can be switched by 8 V instantaneously.

【図面の簡単な説明】[Brief explanation of drawings]

第１図はこの発明の偏光変換器の一実施例を示す図、第
２図（ａ）、　（１））は従来の偏光変換器ＶＣ相当す
る光部品の実施例を示す図、第３図はこの発明の主袂な
構成費素である成品セルの動作を説明するための図であ
る。 図中、　ｆｌｌ［グレーティング、　１２１ｉＩ偏光プ
リズム（３）に偏光変換器、ｆ４１ｒｉ液晶セル、（５
）は合成プリズム、（６）はロッドレンズ、（７）はＬ
ＦｉＤ、＋８１は奄諒。 （９）ニ切替スイッチである。 なお９図中、同一あるいに相当部分には同一符号を付し
て示しておる。FIG. 1 shows an embodiment of the polarization converter of the present invention, FIGS. 2(a) and (1)) show an embodiment of an optical component corresponding to the conventional polarization converter VC, and FIG. FIG. 1 is a diagram for explaining the operation of a finished product cell, which is the main component of the present invention. In the figure, fll [grating, 121iI polarization prism (3), polarization converter, f41ri liquid crystal cell, (5
) is a synthetic prism, (6) is a rod lens, (7) is an L
FiD, +81 is Amaryo. (9) D changeover switch. In FIG. 9, the same or corresponding parts are designated by the same reference numerals.

Claims (1)

【特許請求の範囲】[Claims] 発光ダイオードからの無偏光の光を、Ｐ偏光もしくはＳ
偏光の直線偏光の光に変換する偏光変換器において、偏
光プリズム、ロッドレンズ、２枚の液晶セルおよび合成
プリズムから成り、上記偏光プリズムによつて弁別した
Ｐ偏光もしくはＳ偏光の光を、上記２枚の液晶セルで所
定の直線偏光に変換し、それらの２本の光ビームを合成
プリズムで合成するとともに、電源と結ばれた単極双投
の切替スイッチを切替えることにより、Ｐ偏光およびＳ
偏光を任意に選択できるよう構成したことを特徴とする
偏光変換器。Unpolarized light from a light emitting diode can be converted into P-polarized light or S-polarized light.
A polarization converter that converts polarized light into linearly polarized light is composed of a polarizing prism, a rod lens, two liquid crystal cells, and a synthesis prism, and converts the P-polarized light or S-polarized light discriminated by the polarized prism to the above-mentioned 2. P-polarized light and S-polarized light are converted into predetermined linearly polarized light using two liquid crystal cells, and the two light beams are combined using a combining prism.
A polarization converter characterized by being configured so that polarization can be arbitrarily selected.