JPH052207B2 - - Google Patents
Info
- Publication number
- JPH052207B2 JPH052207B2 JP5163087A JP5163087A JPH052207B2 JP H052207 B2 JPH052207 B2 JP H052207B2 JP 5163087 A JP5163087 A JP 5163087A JP 5163087 A JP5163087 A JP 5163087A JP H052207 B2 JPH052207 B2 JP H052207B2
- Authority
- JP
- Japan
- Prior art keywords
- diffraction grating
- light
- modulation element
- light modulation
- diffraction
- 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.)
- Expired - Lifetime
Links
- 210000001747 pupil Anatomy 0.000 claims description 21
- 238000005286 illumination Methods 0.000 claims description 5
- 230000004907 flux Effects 0.000 claims description 4
- 239000004973 liquid crystal related substance Substances 0.000 description 24
- 239000000758 substrate Substances 0.000 description 23
- 230000003287 optical effect Effects 0.000 description 13
- 238000010586 diagram Methods 0.000 description 12
- 230000010287 polarization Effects 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- 230000005684 electric field Effects 0.000 description 6
- 230000002238 attenuated effect Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 210000001525 retina Anatomy 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 230000008033 biological extinction Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 230000011514 reflex Effects 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
Landscapes
- Viewfinders (AREA)
- Liquid Crystal (AREA)
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明は光変調素子を利用した観察装置に関
し、特に位相型の回折格子と液晶等の屈折率可変
物質を利用して、光の通過や遮光等の光変調を行
つた、例えばカメラ等に好適な観察装置に関する
ものである。Detailed Description of the Invention (Industrial Application Field) The present invention relates to an observation device using a light modulation element, and in particular to an observation device that uses a phase-type diffraction grating and a variable refractive index material such as liquid crystal to The present invention relates to an observation device that performs light modulation such as light shielding and is suitable for, for example, a camera.
（従来の技術）
従来より光変調素子を利用した観察装置は種々
提案されている。このうち従来から良く知られて
いる光変調素子としては、互いに偏光方向が直交
する様に配した一対の偏光板と、この一対の偏光
板間に配され一対の透明基板の相対する基板面に
互いに直交する配向処理を施して液晶を封入した
素子とから成り、この液晶の配向状態をねじれた
状態と基板面に垂直に向いた状態との間でスイツ
チングを行ない入射光の変調をする所謂TN（ツ
ウイストネマツチク）型の液晶を用いた表示素子
がある。(Prior Art) Various observation devices using light modulation elements have been proposed. Among these, the conventionally well-known light modulation element consists of a pair of polarizing plates arranged so that the polarization directions are perpendicular to each other, and a pair of transparent substrates arranged between the pair of polarizing plates on opposite substrate surfaces. The so-called TN device consists of an element in which liquid crystal is sealed with mutually orthogonal alignment treatment, and the alignment state of this liquid crystal is switched between a twisted state and a state perpendicular to the substrate surface to modulate the incident light. There is a display element using a (twisted display) type liquid crystal.
この種の表示素子は構成が簡便で、駆動が容易
なことから多岐に亘り利用されているが、２枚の
偏光板を利用して光束の透過及び遮断を行なう為
に消光時、即ち光透過時の透過率が悪く光束利用
効率の面からは好ましい光変調素子とは言えなか
つた。 This type of display element has a simple structure and is easy to drive, so it is used in a wide variety of applications.However, since it uses two polarizing plates to transmit and block the light flux, it is difficult to transmit light when it is extinguished. The light transmittance was poor, and it could not be said to be a preferable light modulation element from the viewpoint of luminous flux utilization efficiency.
又、液晶を利用した同種の表示素子として、液
晶分子に色素を混入させて用いる所謂ゲスト・ホ
ストモードの液晶素子があるが、この表示素子に
於ても色素が介在する為に消光時の透過率は良く
ても70％程度であつた。 In addition, as a similar type of display element using liquid crystal, there is a so-called guest-host mode liquid crystal element that uses a dye mixed into liquid crystal molecules, but since the dye is present in this display element as well, the transmission during extinction decreases. The rate was at best around 70%.
一方、特公昭53−3928号公報やUSP4251137等
に於て反射型や透過型の位相型の回折格子と液晶
とを組合せた表示素子や可変減色フイルター素子
が開示されている。これらで開示されている素子
は光束利用効率が高くカメラのフアインダー内の
表示素子、あるいはライトバルブ等としては有用
である。 On the other hand, Japanese Patent Publication No. 53-3928 and US Pat. No. 4,251,137 disclose display elements and variable subtractive color filter elements in which a reflection type or transmission type phase type diffraction grating is combined with a liquid crystal. The elements disclosed in these documents have high luminous flux utilization efficiency and are useful as display elements in camera viewfinders, light valves, and the like.
しかしながら、この種の光変調素子を例えば観
察装置としてのカメラのフアインダー系の焦点面
近傍に配置し、輝度の高い被写体（例えば水銀灯
等）をフアインダー系を介して観察した場合、輝
度の高い被写体からの光が、表示を行つている。
回折格子部の一部分に入射すると他の回折格子部
の領域に虹状の回折像が発生し、表示素子として
の品位を低下させ観察装置としての性能が悪下す
る欠点があつた。 However, if this type of light modulation element is placed near the focal plane of the viewfinder system of a camera as an observation device, and a highly bright object (such as a mercury lamp) is observed through the viewfinder system, The light is doing the display.
When the light is incident on a portion of the diffraction grating, a rainbow-like diffraction image is generated in other regions of the diffraction grating, which has the disadvantage of degrading the quality of the display element and deteriorating the performance of the viewing device.
（発明が解決しようとする問題点）
本発明は回折格子より成る光変調素子を利用
し、光の通過や遮光等を行つて情報表示を行う
際、表示パターンとしての回折格子部に高輝度物
体からの光が入射しても観察系を通して他の回折
格子部の表示パターン内に虹状の回折像が生じな
いようにした高品位の観察装置の提供を目的とす
る。(Problems to be Solved by the Invention) The present invention utilizes a light modulation element composed of a diffraction grating, and when displaying information by passing or blocking light, a high-luminance object is placed on the diffraction grating portion as a display pattern. An object of the present invention is to provide a high-quality observation device in which a rainbow-like diffraction image is not generated in a display pattern of another diffraction grating section through an observation system even if light from the above is incident.
（問題点を解決するための手段）
照射系からの光束により照射された光変調素子
を観察系を介して観察する観察装置において、前
記光変調素子は面内で複数の回折格子部を有して
おり、該複数の回折格子部のうち任意の２つの回
折格子部において、各々の格子線のなす角度を
θ、光変調素子への光束の入射角をｉとし
０≦ｉ≦tan-1（Di／2Li）
を満足し、Di，Dpを各々照射系と観察系の瞳径、
Liの照射系の瞳面から光変調素子までの距離、Lp
を光変調素子から観察系の瞳面までの距離、λを
光束の波長、Ｐを格子線の格子ピツチ、Ｎを回折
格子部の媒質の屈折率とし、ｋを
を満足する整数、ｍを
を満足する整数としたとき回折光の回折角ξが観
察系の開口角ηよりも大きいこと即ち
なる条件を満足することである。(Means for solving the problem) In an observation device for observing a light modulation element irradiated with a light beam from an irradiation system via an observation system, the light modulation element has a plurality of diffraction grating parts in a plane. In any two diffraction grating parts among the plurality of diffraction grating parts, the angle formed by each grating line is θ, and the angle of incidence of the light beam on the light modulation element is i, 0≦i≦tan -1 ( D i /2L i ), and D i and D p are the pupil diameters of the irradiation system and observation system, respectively.
The distance from the pupil plane of the illumination system to the light modulation element of L i , L p
is the distance from the light modulation element to the pupil plane of the observation system, λ is the wavelength of the light beam, P is the grating pitch of the grating lines, N is the refractive index of the medium in the diffraction grating section, and k is Let m be an integer that satisfies The diffraction angle ξ of the diffracted light is larger than the aperture angle η of the observation system, that is, when It is necessary to satisfy the following conditions.
（実施例）
第１図は本発明の一実施例の光学系の概略図で
ある。図中１１は照射系であり、例えばカメラ等
においては影響系に相当する、１０は光変調素
子、１２は観察系であり、例えばカメラ等におい
てはフアインダーに相当する。１１ａ，１２ａは
各々瞳面である。(Embodiment) FIG. 1 is a schematic diagram of an optical system according to an embodiment of the present invention. In the figure, 11 is an irradiation system, which corresponds to an influencing system in, for example, a camera, 10 is a light modulation element, and 12 is an observation system, which corresponds to a finder in, for example, a camera. 11a and 12a are pupil planes, respectively.
又Di，Dpは各々照射系と観察系の瞳径、Liは照
射系の瞳面から光変調素子までの距離、Lpは光変
調素子から観察系の瞳面までの距離、ｉは入射
角、ηは観察系の開口角でη＝tan-1（Dp／2Lp）
である。 Also, D i and D p are the pupil diameters of the illumination system and observation system, respectively, L i is the distance from the pupil plane of the illumination system to the light modulation element, L p is the distance from the light modulation element to the pupil plane of the observation system, and i is the incident angle, η is the aperture angle of the observation system, and η=tan -1 (D p /2L p )
It is.
第２図は本発明の観察装置に係る光変調素子１
０の基本構成の説明図である。図中１は屈折率可
変物質で例えば液晶等から成つている。２は使用
波長λに対して透明な物質から成るレリーフ型の
格子線の格子周期Ｐの回折格子、３は透明電極、
４は透明光学部材から成る透明基板、５は任意の
偏光特性を有する入射光、６ａ及び６ｂは各々入
射光５のうちの互いに直交する偏光成分であり、
６ａは紙面に垂直方向の偏光成分、６ｂは偏光成
分６ａと直交し紙面に平行方向の偏光成分を示し
ている。 FIG. 2 shows a light modulation element 1 according to the observation device of the present invention.
FIG. 2 is an explanatory diagram of the basic configuration of 0. In the figure, reference numeral 1 denotes a refractive index variable material, which is made of, for example, liquid crystal. 2 is a diffraction grating with a grating period P of relief-type grating lines made of a material transparent to the used wavelength λ; 3 is a transparent electrode;
4 is a transparent substrate made of a transparent optical member, 5 is incident light having arbitrary polarization characteristics, 6a and 6b are mutually orthogonal polarization components of the incident light 5,
6a indicates a polarized light component perpendicular to the plane of the paper, and 6b indicates a polarized light component perpendicular to the polarized light component 6a and parallel to the plane of the paper.
本光変調素子１０は１対の透明基板４の対向す
る面上に透明電極３を形成して、１対の透明基板
４の一方の透明電極３上に透明物質から成るレリ
ーフ型の回折格子２を設け、屈折率可変物質１を
回折格子２の溝部（凹部）に充填している。そし
て透明電極３を介して電界を印加することにより
屈折率可変物質１の屈折率を変化させている。 This light modulation element 10 has transparent electrodes 3 formed on opposing surfaces of a pair of transparent substrates 4, and a relief-type diffraction grating 2 made of a transparent material on one of the transparent electrodes 3 of the pair of transparent substrates 4. is provided, and the grooves (concavities) of the diffraction grating 2 are filled with the refractive index variable material 1. Then, by applying an electric field through the transparent electrode 3, the refractive index of the variable refractive index material 1 is changed.
次に第２図に示す光変調素子１０の動作原理を
屈折率可変物質１として液晶を用いた場合を例に
とり説明する。 Next, the principle of operation of the light modulation element 10 shown in FIG. 2 will be explained using an example in which liquid crystal is used as the variable refractive index material 1.
今第２図において電界が印加されていない、所
謂静的状態において液晶１は回折格子２の溝方
向、即ち紙面と垂直方向に配向され、ホモジニア
ス配向の状態を維持しているものとする。この静
的状態の光変調素子１０に入射する入射光５の偏
光成分６ａ，６ｂの内、液晶１の配向方向と直交
する成分である偏光成分６ｂは液晶１の常屈折率
npを感じ、又液晶１の配向方向と平行な成分であ
る偏光成分６ａは液晶１の異常屈折率neを感じ
る。ここで回折格子２を成す物質の屈折率をng、
入射光５の波長をλ、回折格子２の厚さをＴとす
れば回折格子が矩形状の場合、入射光５の偏光成
分６ａ，６ｂの各々に対する零次の透過回折光の
回折効率ηpは概略次式(1)で表わされる。 In FIG. 2, it is assumed that in a so-called static state where no electric field is applied, the liquid crystal 1 is oriented in the direction of the grooves of the diffraction grating 2, that is, in the direction perpendicular to the plane of the paper, and maintains a homogeneous orientation state. Of the polarization components 6a and 6b of the incident light 5 that enters the light modulation element 10 in a static state, the polarization component 6b, which is a component perpendicular to the orientation direction of the liquid crystal 1, has an ordinary refractive index of the liquid crystal 1.
The polarized light component 6a , which is a component parallel to the alignment direction of the liquid crystal 1, senses the extraordinary refractive index n e of the liquid crystal 1. Here, the refractive index of the material forming the diffraction grating 2 is n g ,
If the wavelength of the incident light 5 is λ and the thickness of the diffraction grating 2 is T, then when the diffraction grating is rectangular, the diffraction efficiency of the zero-order transmitted diffracted light for each of the polarization components 6a and 6b of the incident light 5 is η p is roughly expressed by the following equation (1).
ηp1/2｛１＋cos（2π・Δn・Ｔ／λ）｝ …(1)
但しΔnは回折格子２の屈折率ngと液晶１の屈
折率np〜neとの屈折率差であり、ホモジニアス配
向の状態では入射光５の偏光成分６ａに対しては
Δn＝｜ne−ng｜となり、又偏光成分６ｂに対し
てはΔn＝｜np−ng｜となる。 η p 1/2 {1+cos (2π・Δn・T/λ)} …(1) However, Δn is the refractive index difference between the refractive index n g of the diffraction grating 2 and the refractive index n p ~ ne of the liquid crystal 1. , in the homogeneous orientation state, Δn=|n e −n g | for the polarization component 6a of the incident light 5, and Δn=|n p −n g | for the polarization component 6b.
従つて(1)式よりΔn＝０のとき、即ちne＝ng又
はnp＝ngのときに零次透過回折光の回折効率ηpは
ηp＝１となる。 Therefore, from equation (1), when Δn=0, that is, when n e =n g or n p =n g , the diffraction efficiency η p of the zero-order transmitted diffracted light becomes η p =1.
又、ΔnT＝（ｍ＋1/2）λ、（ｍ＝０，１，２，
３，…）のときに回折効率ηpはηp＝０となる。 Also, ΔnT=(m+1/2)λ, (m=0,1,2,
3,...), the diffraction efficiency η p becomes η p =0.
次に透明電極３を介して液晶１に電界を印加す
ると、液晶１の配向方向（光学軸方向）が除々に
変化する。このとき入射光５における偏光成分６
ｂは電界の印加に無関係に常時液晶１の常屈折率
npを感じる。 Next, when an electric field is applied to the liquid crystal 1 through the transparent electrode 3, the orientation direction (optical axis direction) of the liquid crystal 1 gradually changes. At this time, the polarization component 6 in the incident light 5
b is the ordinary refractive index of liquid crystal 1 regardless of the application of an electric field.
I feel n p .
これに対して偏光成分６ａは電界の印加量に伴
つて液晶１の異常屈折率neと常屈折率npとを所定
の比率で合成した合成屈折率n〓を感じる。ここで
合成屈折率n〓は液晶１の配向方向の変化に伴つて
変化する。更に電界の印加量を増加させると液晶
１は基板４（透明電極３）に垂直配向されホメオ
トロピツク配向の状態となり、入射光５の偏光成
分６ａ，６ｂは共に液晶１の常屈折率npを感じ飽
和する。このような状態においても入射光５は(1)
式に従つて変調される。 On the other hand, the polarized light component 6a senses a composite refractive index n〓, which is a combination of the extraordinary refractive index n e and the ordinary refractive index n p of the liquid crystal 1 at a predetermined ratio, as the amount of the electric field is applied. Here, the composite refractive index n〓 changes as the alignment direction of the liquid crystal 1 changes. When the amount of applied electric field is further increased, the liquid crystal 1 is aligned perpendicularly to the substrate 4 (transparent electrode 3) and becomes homeotropically aligned, and the polarized components 6a and 6b of the incident light 5 both sense the ordinary refractive index n p of the liquid crystal 1. saturate. Even in this state, the incident light 5 is (1)
Modulated according to Eq.
第３図は光変調素子１０を照射系の焦点面近傍
に配置し、高輝度物体を観察系を介して観察した
ときに光変調領域、即ち複数の回折格子部に虹状
の回折像が発生し、表示素子としての性能を低下
させる要因の説明図である。 Figure 3 shows a light modulation element 10 placed near the focal plane of the irradiation system, and when a high-brightness object is observed through the observation system, a rainbow-shaped diffraction image is generated in the light modulation area, that is, in the plurality of diffraction gratings. FIG. 3 is an explanatory diagram of factors that reduce performance as a display element.
同図において第２図で示した要素と同一要素に
は同符番を付してあり、又透明基板４と回折格子
２との間に配置している透明電極は透明基板４に
比べて極めて薄い為省略してある。 In the figure, the same elements as those shown in FIG. It has been omitted because it is too thin.
同図においては簡単の為、複数の回折格子部の
うち任意の２つの回折格子部２ａ，２ｂを例にと
つている。回折格子２の回折格子部２ａに垂直に
入射した入射光５は液晶１と回折格子２との屈折
率差によつて光変調され、回折格子２の格子線方
向と直交する面内に複数の次数の回折光を生じ
る。これらの回折光のうち零次や低次数の回折角
が比較的小さい回折光７はそのまま透明基板４よ
り出射するが、一部の高次の回折光は、その回折
界φが透明基板４と空気との界面に対する臨界角
をこえると透明基板４と空気との境界面で全反射
し、回折格子部２ｂに入射する場合がある。この
とき他の回折格子部２ｂに入射した光は再度回折
され、その一部の回折光７′は、ある回折角度を
もつて透明基板４外に出射し、それが観察系の入
射瞳にはいると像として認識される。この時、回
折格子部２ａで回折された高次回折光の回折角φ
は波長により異なるため回折格子部２ｂへの入射
位置も波長により異なりその位置のズレが虹とし
て認識される。 In the figure, for the sake of simplicity, arbitrary two diffraction grating sections 2a and 2b among the plurality of diffraction grating sections are taken as an example. The incident light 5 that is perpendicularly incident on the diffraction grating portion 2a of the diffraction grating 2 is optically modulated by the refractive index difference between the liquid crystal 1 and the diffraction grating 2, and a plurality of light beams are formed in a plane orthogonal to the grating line direction of the diffraction grating 2. Produces order diffracted light. Among these diffracted lights, the zero-order and low-order diffraction lights 7 with relatively small diffraction angles are emitted as they are from the transparent substrate 4, but some of the higher-order diffraction lights have their diffraction field φ differing from the transparent substrate 4. If the critical angle with respect to the interface with air is exceeded, the light may be totally reflected at the interface between the transparent substrate 4 and the air and may be incident on the diffraction grating portion 2b. At this time, the light incident on the other diffraction grating section 2b is diffracted again, and a part of the diffracted light 7' is emitted outside the transparent substrate 4 with a certain diffraction angle, and it is transmitted to the entrance pupil of the observation system. If there is one, it will be recognized as a statue. At this time, the diffraction angle φ of the higher order diffracted light diffracted by the diffraction grating section 2a
Since this differs depending on the wavelength, the position of incidence on the diffraction grating section 2b also differs depending on the wavelength, and a shift in the position is recognized as a rainbow.
第４図は回折格子部への入射光の入射方向と回
折光の方向との関係を示すための説明である。５
１は回折格子へ入射する入射光の方向余弦（Ｘ，
Ｙ，Ｚ）、５２はｎ次の回折光の方向余弦（Xo，
Yo，Zo）である。βはＺ軸と入射光５とのなす
角度、αは入射光５のｘ−ｙ平面への射影成分と
ｙ軸とのなす角度である。不図示の回折格子はｘ
−ｙ平面内に、その格子方向がｘ軸と平行となる
ように形成されている。 FIG. 4 is an explanation for showing the relationship between the direction of incidence of light incident on the diffraction grating section and the direction of diffracted light. 5
1 is the direction cosine (X,
Y, Z), 52 is the direction cosine (X o ,
Y o , Z o ). β is the angle between the Z axis and the incident light 5, and α is the angle between the projected component of the incident light 5 on the xy plane and the y axis. The diffraction grating (not shown) is x
- It is formed in the y plane so that its lattice direction is parallel to the x axis.
入射光（Ｘ，Ｙ，Ｚ）と回折光（Xo，Yo，Zo）
とのあいだには
の関係式が成り立つ。 Incident light (X, Y, Z) and diffracted light (X o , Yo , Z o )
Between The relational expression holds true.
但しｎは回折次数、λは波長、Ｐは格子ピツチ
である。いま原点０に対して−ｙ方向に存在する
第１の回折格子に角度ｉで入射する光の方向余弦
（Xp，Yp，Zp）を（０，sini，cosi）とすると第
１の回折格子で発生した回折光のうちで、透明基
板を空気との境界面で全反射した光５が第２の回
折格子へ入射することによつて回折光５２が新た
に発生するが、その回折光の回折角ξは(2)式を用
いて求めると
となる。ここでθは第１の回折格子部の格子線と
第２の回折格子部の格子線のなす角度で、ｋは第
１の回折格子部で発生する回折光の回折次数、ｍ
は第２の回折格子部で発生する回折光を回折次数
であり、それぞれ
を満足する。但しＮは各回折格子部の形成されて
いる基板の屈折率である。 Here, n is the diffraction order, λ is the wavelength, and P is the grating pitch. Now, if the direction cosine (X p , Y p , Z p ) of the light incident at an angle i to the first diffraction grating existing in the -y direction with respect to the origin 0 is (0, sini, cosi), the first diffraction grating is Among the diffracted lights generated by the diffraction grating, the light 5 that is totally reflected at the interface between the transparent substrate and the air enters the second diffraction grating, and a new diffracted light 52 is generated. The diffraction angle ξ of light can be found using equation (2). becomes. Here, θ is the angle between the grating lines of the first diffraction grating section and the grating lines of the second diffraction grating section, k is the diffraction order of the diffracted light generated in the first diffraction grating section, and m
is the diffraction order of the diffracted light generated in the second diffraction grating section, and satisfy. However, N is the refractive index of the substrate on which each diffraction grating portion is formed.
観察系の瞳系がD〓、光変調素子から観察系の
瞳面までの距離がL〓であるため観察系の開口角η
はη＝tan-1（D〓／2L〓）となり、第２の回折格子
部で回折した回折光の回折角ξが
ξ＞tan-1（D〓／2L〓）
を満足するような角度θ（θ；第１の回折格子部
と第２の回折格子部の格子線のなす角度）に定め
れば不要な回折光は観察系の瞳外に飛ばされてし
まい虹状の回折像は視認されなくなる。 Since the pupil system of the observation system is D〓 and the distance from the light modulation element to the pupil plane of the observation system is L〓, the aperture angle η of the observation system is
is η=tan -1 (D〓/2L〓), and the angle θ is such that the diffraction angle ξ of the diffracted light diffracted by the second diffraction grating section satisfies ξ>tan -1 (D〓/2L〓). If it is set to (θ: the angle formed by the grating lines of the first diffraction grating section and the second diffraction grating section), unnecessary diffracted light will be blown out of the pupil of the observation system, and a rainbow-shaped diffraction image will not be visible. It disappears.
そこで本実施例では回折格子部２ａ，２ｂにお
ける格子線のなす角θを前述の(A)式を満足するよ
うに設定することにより、入射光５が回折格子部
２ａに入射し、回折した回折光が回折格子部２ａ
の形成されていない他の面、例えば透明基板４の
空気と接する面で全反射した後、回折格子部２ｂ
の領域に入射した際、回折した回折光が観察系の
入射瞳内に殆どはいらないようにして、人間の眼
に対して回折格子部２ｂからの虹状の回折像の発
生を防止している。 Therefore, in this embodiment, by setting the angle θ formed by the grating lines in the diffraction grating parts 2a and 2b so as to satisfy the above-mentioned formula (A), the incident light 5 is incident on the diffraction grating part 2a, and the diffracted light is The light passes through the diffraction grating section 2a
After being totally reflected on another surface on which the diffraction grating portion 2b is not formed, for example, the surface of the transparent substrate 4 that is in contact with air, the diffraction grating portion 2b
When the diffraction light enters the region of , almost no diffracted light enters the entrance pupil of the observation system, thereby preventing the generation of a rainbow-like diffraction image from the diffraction grating portion 2b to the human eye. .
又同様に回折格子部２ｂに入射し回折した回折
光が全反射した後に他の回折格子部２ａに入射し
ても、そこで回折した回折光が観察系の入射瞳内
に殆どはいらないようにもしている。 Similarly, even if the diffracted light that is incident on the diffraction grating section 2b is totally reflected and then enters the other diffraction grating section 2a, the diffracted light that is diffracted there will hardly enter the entrance pupil of the observation system. ing.
第３図においては透明回折光を例にとり説明し
たが、反射回折光についても全く同様である。 In FIG. 3, transparent diffraction light has been explained as an example, but the same applies to reflected diffraction light.
第５図は本発明に係る観察装置をカメラのフア
インダー系の一部に適用したときの一実施例の説
明図である。同図において１０は光変調素子、４
１は跳ね上げミラー、４２はピント板、４３はコ
ンデンサーレンズ、４４はペンタプリズム、４５
は接眼レンズである。不図示の影響レンズを透過
した光は跳ね上げミラー４１によりフアインダー
光学系に導かれ、ピント板４２のピント面上に結
像する。ピント板４２から出射する光は撮影レン
ズのＦナンバー及びマツトの拡散特性に応じた強
度で拡散し、その一部がコンデンサーレンズ４
３、ペンタプリズム４４、接眼レンズ４５を介し
て人間の眼に到達する。ここで実際に眼に入射す
る光は、観察系を構成するコンデンサーレンズ４
３、ペンタプリズム４４、接眼レンズ４５の入射
瞳及び眼の瞳径により制限を受けたもので一般の
一眼レフカメラを例にとつてみるとピント板４２
上で光軸を中心に通常開口角η≒３［deg］の範
囲内で出射した光となる。 FIG. 5 is an explanatory diagram of an embodiment in which the observation device according to the present invention is applied to a part of the viewfinder system of a camera. In the figure, 10 is a light modulation element, 4
1 is a flip-up mirror, 42 is a focusing plate, 43 is a condenser lens, 44 is a pentaprism, 45
is the eyepiece. The light transmitted through an influence lens (not shown) is guided to a finder optical system by a flip-up mirror 41, and is imaged on the focusing surface of a focusing plate 42. The light emitted from the focusing plate 42 is diffused with an intensity according to the F number of the photographic lens and the diffusion characteristics of the lens, and a portion of the light is emitted by the condenser lens 4.
3. The light reaches the human eye via the pentaprism 44 and the eyepiece 45. Here, the light that actually enters the eye is transmitted through the condenser lens 4 that constitutes the observation system.
3. It is limited by the entrance pupil of the pentaprism 44, the eyepiece 45, and the pupil diameter of the eye. Taking a general single-lens reflex camera as an example, the focusing plate 42
The light is normally emitted within the range of an aperture angle η≒3 [deg] around the optical axis.
本実施例における光変調素子１０はピント板４
２のピント面近傍に配置され、不図示の駆動装置
により表示、非表示状態が選択される。非表示状
態では光変調素子１０は屈折率の一様な透明基板
を見なされ、ピント面上に結像した被写体像は変
調されずに、コンデンサーレンズ４３、ペンタプ
リズム４４、接眼レンズ４５を介して眼の網膜上
に、そのまま結像される。表示状態では光変調素
子１０に入射する光の一部は回折格子部からなる
表示パターン部分において回折される。回折され
た光のうち回折角の大きな成分は眼の視野外にと
ばされるために被写体光の一部減光されたように
視認され、被写体像と重なつた表示がなされう
る。 The light modulation element 10 in this embodiment is the focusing plate 4
2, and a display or non-display state is selected by a drive device (not shown). In the non-display state, the light modulation element 10 is treated as a transparent substrate with a uniform refractive index, and the subject image formed on the focal plane is not modulated but is transmitted through the condenser lens 43, pentaprism 44, and eyepiece lens 45. The image is directly formed on the retina of the eye. In the display state, a portion of the light incident on the light modulation element 10 is diffracted at the display pattern portion made up of the diffraction grating portion. A component of the diffracted light with a large diffraction angle is blown out of the field of view of the eye, so that it is visually perceived as if part of the subject light has been attenuated, and the display may overlap with the subject image.
カメラの光学系において、不図示の撮影レン
ズ、跳ね上げミラー４１、ピント板１２からなる
照射系からの入射光束の光変調素子１０への入射
角ｉ＝20［deg］，波長λ＝0.55［μｍ］，回折格子
同期Ｐ＝1.5［μｍ］、光変調素子１０の透明基板
の屈折率ｎ＝1.5，観察系の開口角η＝３［deg］
とすると(A)式より
θ≧18［deg］
となり、任意の２つの回折格子部の格子線のなす
角度θをθ≧18［deg］と設定することにより、
任意の回折格子部に入射し、回折した回折光が、
回折格子部の形成されていない他の面、例えば、
透明基板の空気と接する面で全反射した後、他の
回折格子部に入射した際、回折した回折光が観察
系の入射瞳内に殆どはいらない為、虹状の回折像
は発生しない。 In the optical system of the camera, the incident angle of the incident light beam from the irradiation system consisting of a photographing lens (not shown), flip-up mirror 41, and focusing plate 12 to the light modulation element 10 is 20 [deg], and the wavelength λ is 0.55 [μm]. ], diffraction grating synchronization P = 1.5 [μm], refractive index n of the transparent substrate of the light modulation element 10 = 1.5, aperture angle η of the observation system = 3 [deg]
Then, from equation (A), θ≧18[deg], and by setting the angle θ between the grating lines of any two diffraction grating parts as θ≧18[deg],
The diffracted light that is incident on an arbitrary diffraction grating section and diffracted is
Other surfaces on which the diffraction grating portion is not formed, for example,
After being totally reflected by the surface of the transparent substrate in contact with air, when the diffracted light enters another diffraction grating section, almost no diffracted light enters the entrance pupil of the observation system, so no rainbow-shaped diffraction image is generated.
第６図は第５図で用いた光変調素子１０の平面
図を拡大した図、第７図は格子線方向の方位図で
ある。 FIG. 6 is an enlarged plan view of the light modulation element 10 used in FIG. 5, and FIG. 7 is an azimuth view in the grid line direction.
４は透明基板、２１，２２，２３，２４，２
６，２７，２８，２９は回折格子部で各回折格子
部内の斜線方向は格子線方向である。２１′，２
２′，２３′，２４′，２５′，２６′，２７′，２
８′，２９′は各回折格子部の格子線方向で、各格
子線方向は20゜以上の角度をなしている。 4 is a transparent substrate, 21, 22, 23, 24, 2
6, 27, 28, and 29 are diffraction grating portions, and the diagonal line direction within each diffraction grating portion is the grating line direction. 21', 2
2', 23', 24', 25', 26', 27', 2
8' and 29' are the grating line directions of each diffraction grating section, and each grating line direction forms an angle of 20 degrees or more.
光変調素子１０の表示パターンは８つのセグメ
ントより構成され個々のセグメントは１つの回折
格子部をなしている８つの回折格子部の格子線方
向は異なり各回折格子部の格子線のなす角度θは
θ≧20゜である。そのため任意の回折格子部に入
射し回折した回折光が、回折格子の形成されてい
ない透明基板の空気と接する面で全反射した後、
他の回折格子部に入射しても回折した不要回折光
は観察系の瞳外に飛ばされるため、虹状の回折像
は発生せず、表示品位の低下を防止できる。 The display pattern of the light modulation element 10 is composed of eight segments, each segment forming one diffraction grating section. The grating line directions of the eight diffraction grating sections are different, and the angle θ formed by the grating lines of each diffraction grating section is θ≧20°. Therefore, after the diffracted light that is incident on any diffraction grating part and is diffracted, is totally reflected on the surface of the transparent substrate in contact with air where no diffraction grating is formed,
Unnecessary diffracted light that is diffracted even if it is incident on other diffraction grating parts is blown out of the pupil of the observation system, so a rainbow-like diffraction image is not generated, and deterioration in display quality can be prevented.
第８図は本発明の一実施例でビデオカメラのフ
アインダー光学系に光変調素子を組み入れた場合
の光学配置図である。３０は光変調素子、３１は
対物レンズ、３２は１次ピント面、３３はエレク
ターレンズ、３４は接眼レンズで、対物レンズ３
１とエレクターレンズ３３は不図示の撮影レンズ
と半透鏡、反射鏡とともに観察装置における照射
系を構成し、接眼レンズ３４は観察系を構成して
いる。不図示の撮影レンズを透過した被写体光の
一部は半透鏡によりフアインダー光学系に導かれ
対物レンズ３１を介して、１次ピント面３２に像
を結ぶ。１次ピント面３２より発散する光はエレ
クターレンズ３３より２次ピント面に配置された
光変調素子３０上に結像後、その透過光は接眼レ
ンズ３４を介して人間の眼に到達する。 FIG. 8 is an optical layout diagram of an embodiment of the present invention in which a light modulation element is incorporated into a viewfinder optical system of a video camera. 30 is a light modulation element, 31 is an objective lens, 32 is a primary focus plane, 33 is an erector lens, 34 is an eyepiece lens, and the objective lens 3
1 and the erector lens 33 constitute an irradiation system in the observation device together with a photographing lens (not shown), a semi-transparent mirror, and a reflecting mirror, and the eyepiece lens 34 constitutes an observation system. A part of the subject light transmitted through a photographing lens (not shown) is guided to a finder optical system by a semi-transparent mirror, and is focused on a primary focus plane 32 via an objective lens 31 . The light diverging from the primary focus plane 32 is imaged by the erector lens 33 onto the light modulation element 30 disposed on the secondary focus plane, and then the transmitted light reaches the human eye via the eyepiece lens 34.
本発明における光変調素子３０は第２図に示し
た構造をとり不図示の駆動装置により表示、非表
示状態が選択される。非表示状態では光変調素子
３０は屈折率の一様な透明基板と見なされ２次ピ
ント面上に結像した被写体像は変調されずに接眼
レンズ３４を介して眼の網膜上にそのまま結像さ
れる。表示状態では、光変調素子３０に入射する
光の一部は回折格子からなる表示パターン部分に
おいて回折される。回折された光のうち回折角の
大きな成分は眼の視野外にとばされるために被写
体光の一部が減光されたように視認され被写体像
と重なつた表示がなされうる。 The light modulation element 30 according to the present invention has the structure shown in FIG. 2, and a display or non-display state is selected by a drive device (not shown). In the non-display state, the light modulation element 30 is regarded as a transparent substrate with a uniform refractive index, and the subject image formed on the secondary focus plane is directly imaged on the retina of the eye via the eyepiece 34 without being modulated. be done. In the display state, a portion of the light incident on the light modulation element 30 is diffracted at the display pattern portion formed by the diffraction grating. A component of the diffracted light with a large diffraction angle is blown out of the field of view of the eye, so that a portion of the subject light may be visually perceived as being attenuated, and may be displayed overlapping the subject image.
一般にビデオカメラの光学系において光フアイ
ンダー系の２次ピント面上に光変調素子３０を配
置した場合、不図示の撮影レンズ、半透鏡、反射
鏡と対物レンズ３１、エレクターレンズ３３から
なる照射系より光変調素子３０に入射する光束の
最大入射角は約５［deg］で、観察系である接眼
レンズ３４の開口角η＝６［deg］である。入射
光の波長λ＝0.55［μｍ］，回折格子周期Ｐ＝1.5
［μｍ］光変調素子３０の透明基板の屈折率ｎ＝
1.5とすると(A)式より
θ≧10［deg］
となる。 Generally, in the optical system of a video camera, when the light modulation element 30 is placed on the secondary focus plane of the optical finder system, the illumination system consisting of a photographing lens (not shown), a semi-transparent mirror, a reflecting mirror, an objective lens 31, and an erector lens 33. The maximum angle of incidence of the light beam incident on the light modulation element 30 is approximately 5 [deg], and the aperture angle η of the eyepiece lens 34, which is the observation system, is 6 [deg]. Wavelength of incident light λ = 0.55 [μm], diffraction grating period P = 1.5
[μm] Refractive index n of the transparent substrate of the light modulation element 30 =
If it is 1.5, then θ≧10[deg] from equation (A).
すなわち表示パターンに従つて複数の回折格子
部が形成された光変調素子において、任意の２つ
の回折格子部に入射し回折した回折光が、回折格
子の形成されていない透明基板の空気と接する面
で全反射した後、他の回折格子部に入射しても回
折した不要回折光は観察系の瞳外に飛ばされる
為、虹状の回折像は発生さず表示品位の低下は防
止される。 In other words, in a light modulation element in which a plurality of diffraction grating parts are formed according to a display pattern, the diffracted light incident on and diffracted by any two diffraction grating parts is transmitted to the surface of the transparent substrate in contact with air where no diffraction grating is formed. After being totally reflected, unnecessary diffracted light that is diffracted even if it enters other diffraction grating parts is blown out of the pupil of the observation system, so a rainbow-like diffraction image is not generated and a deterioration in display quality is prevented.
（発明の効果）
以上のように本発明によれば表示パターンとな
る複数の回折格子部の格子線のなす角度を前述の
(A)式を満足するように特定することにより、回折
格子部で発生し、回折格子部の形成されていない
他の面で全反射した回折光が他の回折格子部に入
射し、虹状の回折像を発生するのを防止した高品
位の表示を可能とした光変調素子を用いた観察装
置を達成することができる。(Effects of the Invention) As described above, according to the present invention, the angles formed by the grating lines of the plurality of diffraction grating portions forming the display pattern are adjusted as described above.
By specifying equation (A) so that it is satisfied, the diffracted light generated in the diffraction grating section and totally reflected on other surfaces where no diffraction grating section is formed will enter the other diffraction grating section, forming a rainbow-like pattern. It is possible to achieve an observation device using a light modulation element that enables high-quality display while preventing the generation of diffraction images.
第１図は本発明の一実施例の光学系の概略図、
第２図は本発明の観察装置に用いる光変調素子の
一実施例の説明図、第３図は第２図の光変調素子
における回折光の全反射発生の説明図、第５図は
本発明をカメラのフアインダー系に適用したとき
の説明図、第４図は光変調素子における回折方向
の説明図、第６図は第５図で用いた光変調素子の
平面図、第７図は第６図の回折格子部の回折方向
の説明図、第８図は本発明をビデオカメラの光学
フアインダー系に適用した時の説明図である。
図中１０は光変調素子、１１は照射系、１２は
観察系、１は屈折率可変物質、２は回折格子、３
は透明電極、４は透明基板、５は入射光、６ａ，
６ｂは各々偏光成分、７は出射光、２ａ，２ｂ，
２１，２２，２３，２４，２６，２７，２８，２
９は回折格子部である。
FIG. 1 is a schematic diagram of an optical system according to an embodiment of the present invention;
FIG. 2 is an explanatory diagram of one embodiment of the light modulation element used in the observation device of the present invention, FIG. 3 is an explanatory diagram of occurrence of total reflection of diffracted light in the light modulation element of FIG. 2, and FIG. 5 is an explanatory diagram of the invention. 4 is an explanatory diagram of the diffraction direction in the light modulation element, Figure 6 is a plan view of the light modulation element used in Figure 5, and Figure 7 is an illustration of the light modulation element used in Figure 6. FIG. 8 is an explanatory diagram of the diffraction direction of the diffraction grating portion in the figure, and FIG. 8 is an explanatory diagram when the present invention is applied to an optical finder system of a video camera. In the figure, 10 is a light modulation element, 11 is an irradiation system, 12 is an observation system, 1 is a refractive index variable material, 2 is a diffraction grating, 3
is a transparent electrode, 4 is a transparent substrate, 5 is incident light, 6a,
6b is each polarized light component, 7 is output light, 2a, 2b,
21, 22, 23, 24, 26, 27, 28, 2
9 is a diffraction grating section.
Claims (1)
子を観察系を介して観察する観察装置において、
前記光変調素子は面内で複数の回折格子部を有し
ており、該複数の回折格子部のうち任意の２つの
回折格子部において、各々の格子線のなす角度を
θ、光変調素子への光束の入射角をｉとし ０≦ｉ≦tan-1（Di／2Li） を満足し、Di，Dpを各々照射系と観察系の瞳径、
Liを照射系の瞳面から光変調素子までの距離、Lp
を光変調素子から観察系の瞳面までの距離、λを
光束の波長、Ｐを格子線の格子ピツチ、Ｎを回折
格子部の媒質の屈折率とし、ｋを を満足する整数、ｍを を満足する整数としたとき なる条件を満足することを特徴とする観察装置。 ２ 前記回折格子部は位相回折格子であり、該位
相回折格子を構成する複数の位相媒体の少なくと
も一方は、屈折率可変媒体であり、該屈折率可変
媒体の屈折率を制御する手段を具備することを特
徴とする特許請求の範囲第１項記載の観察装置。[Scope of Claims] 1. In an observation device for observing a light modulation element irradiated with a light beam from an irradiation system via an observation system,
The light modulation element has a plurality of diffraction grating parts in a plane, and in any two diffraction grating parts among the plurality of diffraction grating parts, the angle between each grating line is θ, and Let the incident angle of the luminous flux be i, satisfy 0≦i≦tan -1 (D i /2L i ), and D i and D p are the pupil diameters of the irradiation system and observation system, respectively,
L i is the distance from the pupil plane of the illumination system to the light modulation element, L p
is the distance from the light modulation element to the pupil plane of the observation system, λ is the wavelength of the light beam, P is the grating pitch of the grating lines, N is the refractive index of the medium in the diffraction grating section, and k is Let m be an integer that satisfies When is an integer that satisfies An observation device characterized by satisfying the following conditions. 2. The diffraction grating section is a phase diffraction grating, and at least one of the plurality of phase media constituting the phase diffraction grating is a refractive index variable medium, and includes means for controlling the refractive index of the refractive index variable medium. An observation device according to claim 1, characterized in that:
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5163087A JPS63218919A (en) | 1987-03-06 | 1987-03-06 | Observing device |
| US07/035,017 US4856869A (en) | 1986-04-08 | 1987-04-06 | Display element and observation apparatus having the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5163087A JPS63218919A (en) | 1987-03-06 | 1987-03-06 | Observing device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63218919A JPS63218919A (en) | 1988-09-12 |
| JPH052207B2 true JPH052207B2 (en) | 1993-01-12 |
Family
ID=12892167
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5163087A Granted JPS63218919A (en) | 1986-04-08 | 1987-03-06 | Observing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63218919A (en) |
-
1987
- 1987-03-06 JP JP5163087A patent/JPS63218919A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63218919A (en) | 1988-09-12 |
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