JP2545524B2 - Space filtering lens system - Google Patents

Space filtering lens system

Info

Publication number
JP2545524B2
JP2545524B2 JP62002044A JP204487A JP2545524B2 JP 2545524 B2 JP2545524 B2 JP 2545524B2 JP 62002044 A JP62002044 A JP 62002044A JP 204487 A JP204487 A JP 204487A JP 2545524 B2 JP2545524 B2 JP 2545524B2
Authority
JP
Japan
Prior art keywords
lens
light
spatial
lens system
spatial filter
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
Application number
JP62002044A
Other languages
Japanese (ja)
Other versions
JPS63169613A (en
Inventor
壽己 西
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Sheet Glass Co Ltd
Original Assignee
Nippon Sheet Glass Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Sheet Glass Co Ltd filed Critical Nippon Sheet Glass Co Ltd
Priority to JP62002044A priority Critical patent/JP2545524B2/en
Publication of JPS63169613A publication Critical patent/JPS63169613A/en
Application granted granted Critical
Publication of JP2545524B2 publication Critical patent/JP2545524B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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  • Lenses (AREA)
  • Optical Filters (AREA)

Description

【発明の詳細な説明】 [産業上の利用分野] 本発明は、レンズ焦点面に空間フィルターを配置し
て、フーリエ変換された空間周波数領域で通過帯域の制
限を行なうようにした空間フィルタリングレンズ系に関
する。
The present invention relates to a spatial filtering lens system in which a spatial filter is arranged on a focal plane of a lens to limit a pass band in a Fourier-transformed spatial frequency domain. Regarding

[従来技術の説明] レンズの焦点面に各種形状の空間フィルターを配置
し、フーリエ変換された空間周波数領域で特定の周波数
成分を遮断し、他の周波数成分光を通過させて該成分光
のみによる結像を得る空間フィルタリングの原理は、従
来から光学の分野で広く知られている。
[Description of the Related Art] Spatial filters of various shapes are arranged on the focal plane of the lens, a specific frequency component is blocked in the Fourier-transformed spatial frequency domain, and other frequency component light is passed through, and only the component light is used. The principle of spatial filtering for obtaining an image is widely known in the field of optics.

上記の空間フィルタリング処理で使用するフーリエ変
換用のレンズとしては、通常複数枚構成の球面レンズが
用いられ、空間フィルターとしては、ガラス板上に真空
蒸着などの被膜形成手段により金属膜を所定のフィルタ
ーパターンで形成したものが用いられている。
As the Fourier transform lens used in the above spatial filtering processing, a spherical lens having a plurality of lenses is usually used, and as the spatial filter, a metal film is formed on a glass plate by a film forming means such as vacuum deposition to obtain a predetermined filter. What is formed in a pattern is used.

[発明が解決しようとする問題点] 上記のような空間フィルタリングレンズ系を構成する
場合、複数個のレンズや空間フィルターを枠体に光軸合
せ調整して固定する必要がある。
[Problems to be Solved by the Invention] When configuring the spatial filtering lens system as described above, it is necessary to adjust a plurality of lenses and spatial filters to the frame body and adjust and fix the optical axes.

特にレンズ直径が数mm以下の微小光学系を構成しよう
とすると、小口径レンズの研磨製作は著しい困難を伴な
い大幅なコストアップとなってしまう。
In particular, if a minute optical system having a lens diameter of several mm or less is to be constructed, polishing and manufacturing of a small-diameter lens will cause a significant increase in cost with significant difficulty.

[問題点を解決する手段] 断面内で半径方向に屈折率が変化する屈折率分布型媒
質から成る少なくとも2枚構成のレンズ系の、物体側レ
ンズの焦点面上に、特定の空間周波数範囲の光を遮断
し、他の周波数範囲の光の通過を許す空間フィルターを
配置した。
[Means for Solving Problems] A lens system having at least two lenses, which is composed of a gradient index medium whose refractive index changes in the radial direction in a cross section, has a specific spatial frequency range on a focal plane of an object side lens. A spatial filter was placed to block light and allow light in other frequency ranges to pass.

[作用、効果] 光軸に垂直な断面内で半径方向に屈折率が変化してい
る屈折率分布型レンズは、レンズ媒質自体が屈折力で持
つため、レンズの両端面(入出射面)を平面とした状態
で球面レンズと同様の結像作用を有し、研磨加工が容易
であるとともに、屈折率分布の形状を適当に選ぶことに
より、均質媒質を用いた非球面レンズと同等の球面収差
補正が可能である。
[Operation and effect] In the gradient index lens in which the refractive index changes in the radial direction in the cross section perpendicular to the optical axis, the lens medium itself has a refractive power, so that both end surfaces (entrance / emission surface) of the lens are It has the same image-forming effect as a spherical lens in a flat state, is easy to polish, and has a spherical aberration equivalent to that of an aspherical lens using a homogeneous medium by selecting the shape of the refractive index distribution appropriately. Correction is possible.

したがって、本発明の空間フィルタリングレンズ系に
よれば、物体側レンズの長さを端面を焦点面とする長さ
に選ぶことにより、平坦なレンズ面に対して空間フィル
タを密着配置するだけで精密な空間フィルタリング処理
を行なうことができる。
Therefore, according to the spatial filtering lens system of the present invention, by selecting the length of the object-side lens as the length with the end surface as the focal plane, it is possible to precisely adjust the spatial filter by closely arranging it on the flat lens surface. Spatial filtering processing can be performed.

[実 施 例] 以下本発明を図面に示した実施例に基づいて詳細に説
明する。
[Examples] The present invention will be described below in detail based on the examples shown in the drawings.

第1図において1は第1レンズ、2は第2レンズであ
り、両レンズ1,2はいずれも、光軸3と直交する面内に
おいて屈折率が光軸3上で最大で外周に向けて次第に変
化する屈折率分布が付与されている。そしてレンズ1と
レンズ2とを光軸3を一致させて配列し、両レンズ1,2
の対向する面1B及び2A間に空間フィルタ板4を介在させ
て接着接合している。そして第1レンズ1の物体側端面
1Aの曲率半径R1、像側端面1Bの曲率半径R2、第2レンズ
2の物体側端面2Aの曲率半径R3、他方端面2Bの曲率半径
R4のいずれも図示例では無限大すなわち平面としてあ
る。そして第1レンズ1は、第3図に示すように焦点面
5が一方のレンズ端面1Bと一致するように一例として1/
4ピッチ長としてある。
In FIG. 1, 1 is a first lens, 2 is a second lens, and both lenses 1 and 2 have a maximum refractive index on the optical axis 3 in the plane orthogonal to the optical axis 3 toward the outer periphery. A graded refractive index distribution is given. Then, the lens 1 and the lens 2 are arranged so that the optical axes 3 thereof coincide with each other, and both lenses 1 and 2 are arranged.
The surfaces 1B and 2A facing each other are bonded and joined with the spatial filter plate 4 interposed. Then, the object side end surface of the first lens 1
Curvature radius R1 of 1A, curvature radius R2 of image-side end surface 1B, curvature radius R3 of object-side end surface 2A of second lens 2, curvature radius of other end surface 2B
In the illustrated example, each of R4 is infinity, that is, a plane. Then, the first lens 1 is, for example, 1/1 so that the focal plane 5 coincides with one lens end surface 1B as shown in FIG.
There are 4 pitch lengths.

フィルタ板4は第2図に示すように外径をレンズ1,2
と同一にした透明円板6の中心に蒸着、印刷等周知の被
模形成手段を用いて小円径の遮光部7を形成してあり、
物体9から発して光軸3に対して平行ないしは小さい角
度を成してレンズ1に入射する光線群は端面1B(焦点面
5)で上記遮光部7で遮断され、レンズ2へは入射しな
い。一方、第4図に示すように物体9から出射して光軸
3に対し比較的大きい角度を成してレンズ1に入射する
光線10は、他端面1Bで光軸から離れた位置に集光し、フ
ィルタ板4の遮光部7周囲に設けられた円環状の透光部
8を通過した後レンズ2に入射し、レンズ2の面2Bから
一定距離をおいた点で像11を結像する。
As shown in FIG. 2, the filter plate 4 has an outer diameter of lenses 1, 2
A light-shielding portion 7 having a small diameter is formed in the center of the transparent disc 6 which is the same as the above, using a well-known pattern forming means such as vapor deposition and printing.
A group of light rays emitted from the object 9 and incident on the lens 1 in parallel or at a small angle with respect to the optical axis 3 is blocked by the light shielding portion 7 at the end surface 1B (focal plane 5) and does not enter the lens 2. On the other hand, as shown in FIG. 4, a light beam 10 which is emitted from the object 9 and enters the lens 1 at a relatively large angle with respect to the optical axis 3 is condensed at a position apart from the optical axis at the other end surface 1B. Then, after passing through an annular light-transmitting portion 8 provided around the light-shielding portion 7 of the filter plate 4, the light enters the lens 2 and forms an image 11 at a point a certain distance from the surface 2B of the lens 2. .

つまり図示例は、光軸に対し一定以上の角度をもった
光線だけを通過させる高域空間周波数通過フィルタリン
グを行なっている。
That is, in the illustrated example, high-pass spatial frequency pass filtering is performed in which only light rays having an angle of a certain value or more with respect to the optical axis are passed.

上記以外にフィルタ板4の遮光部7の形状を種々変え
ることにより、一般的に物体から発する光線のうち特定
の空間周波数範囲の成分を遮光し、他の周波数成分の光
線のみで結像させることができ、微分像の形成等の画像
処理を行なうことができる。
In addition to the above, by changing the shape of the light-shielding portion 7 of the filter plate 4 in general, light rays emitted from an object are shielded from components in a specific spatial frequency range, and images are formed only with light rays having other frequency components. Therefore, image processing such as formation of a differential image can be performed.

なお図示例では両レンズ1,2の、空間フィルタ板4と
接する面以外のレンズ端面1A,2Bも平面としているが、
これらの面は曲面であってもよい。ただし図示例のよう
にレンズ1,2のすべての面を平面としておけば、レンズ
面加工が最も容易になり有利である。
In the illustrated example, the lens end surfaces 1A and 2B of both lenses 1 and 2 other than the surface in contact with the spatial filter plate 4 are also flat,
These surfaces may be curved. However, if all the surfaces of the lenses 1 and 2 are made flat as in the illustrated example, it is advantageous because the lens surface processing is easiest.

次に本発明における空間フィルタの他の構造例を示
す。
Next, another structural example of the spatial filter in the present invention will be shown.

第5図は、前述例のようにレンズとは別体の透明板に
空間フィルタを設けるかわりに、第1レンズ1の出射面
1Bに空間フィルタの遮光部分7を蒸着、印刷等により直
接被膜として付着形成し、この部分的な遮光被膜7周辺
に残したレンズ面を空間フィルタの透光部8として使用
している。第6図の例は、1つの基板に特性の異なる複
数の空間フィルタ、すなわち形状の異なる遮光部7及び
透光部8の組を設けたものであり、フィルタ板4をレン
ズ光軸を横切る方向に移動させることにより、特定の空
間周波数成分光による像から他の成分による像へすばや
く切り変えることができる。
FIG. 5 shows the emission surface of the first lens 1 instead of providing a spatial filter on a transparent plate separate from the lens as in the above-mentioned example.
A light-shielding portion 7 of the spatial filter is directly formed as a coating on 1B by vapor deposition, printing or the like, and the lens surface left around this partial light-shielding coating 7 is used as a light-transmitting portion 8 of the spatial filter. In the example of FIG. 6, a plurality of spatial filters having different characteristics, that is, a set of a light-shielding portion 7 and a light-transmitting portion 8 having different shapes are provided on one substrate, and the filter plate 4 is arranged in a direction crossing the lens optical axis. By moving the image to a specific spatial frequency component light, it is possible to quickly switch to an image of another component.

第7図の例は空間フィルタの切り変えを機械的可動部
分を用いずに行なうようにしたものであり、フィルタ板
4を液晶素子で構成し、例えば中心付近の小面積部分4A
とこれを囲む外周部分4Bとの二つの独立に制御可能なセ
クションに分け、両セクションに印加する電圧をスイッ
チ12,13で変更することにより、遮光部分と透光部分と
を中心セクションと外周セクションとに切り換え得るよ
うにしている。遮光部と透光部との切り換えを非機械的
に行なう空間フィルタとして液晶以外に、電気的あるい
は磁気的入力を変化させることにより透光率が変化する
一般の表示素子、光学的シャッター等の素子を用いるこ
とができる。
In the example shown in FIG. 7, the spatial filter is switched without using any mechanically movable part. The filter plate 4 is composed of a liquid crystal element, for example, a small area part 4A near the center.
It is divided into two independently controllable sections, the outer peripheral section 4B surrounding this and the sections to be applied, and the voltage applied to both sections is changed by the switches 12 and 13, so that the light-shielding section and the light-transmitting section are divided into the central section and the outer section. I am trying to switch to and. As a spatial filter for non-mechanically switching between the light-shielding portion and the light-transmitting portion, in addition to liquid crystal, a general display element whose optical transmittance changes by changing an electrical or magnetic input, an element such as an optical shutter Can be used.

[発明の効果] 本発明によれば枠体を用いる必要なく簡単に微小な空
間フィルタリング光学系を構成することができる。
EFFECTS OF THE INVENTION According to the present invention, it is possible to easily configure a minute spatial filtering optical system without using a frame.

すなわち、屈折率分布型媒質を用いているため、空間
フィルタを配置すべきレンズ焦点面をレンズ端面と一致
させてしかもこの面を平面にできるので、フィルタはレ
ンズ面に密着配置するだけで位置合せが自動的に行なわ
れ、したがって組み立てが極めて容易で量産に適してい
る。
That is, since the gradient index medium is used, the lens focal plane on which the spatial filter should be placed can be aligned with the lens end surface, and this surface can be made flat, so that the filter can be aligned by simply placing it closely on the lens surface. Is performed automatically, and therefore is extremely easy to assemble and suitable for mass production.

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

第1図は本発明の第1の実施例を示す側断面図、第2図
は空間フィルタ板の正面図、第3図及び第4図は第1図
の例で空間周波数の異なる光に対する空間フィルタの各
作用を示す側断面図、第5図は本発明の第2実施例を示
す斜視図、第6図は本発明の第3実施例を示す斜視図、
第7図は本発明の第4実施例を示す斜視図である。 1,2……屈折率分布型レンズ、3……光軸 4……空間フィルタ板、5……焦点面 7……遮光部、8……透光部、9……物体 11……像、12,13……スイッチ
1 is a side sectional view showing a first embodiment of the present invention, FIG. 2 is a front view of a spatial filter plate, and FIGS. 3 and 4 are examples of FIG. 1 showing a space for light having different spatial frequencies. FIG. 5 is a side sectional view showing each action of the filter, FIG. 5 is a perspective view showing a second embodiment of the present invention, and FIG. 6 is a perspective view showing a third embodiment of the present invention.
FIG. 7 is a perspective view showing a fourth embodiment of the present invention. 1,2 ... Gradient index type lens, 3 ... Optical axis 4 ... Spatial filter plate, 5 ... Focal plane 7 ... Shading portion, 8 ... Translucent portion, 9 ... Object 11 ... Image, 12,13 …… Switch

Claims (2)

(57)【特許請求の範囲】(57) [Claims] 【請求項1】半径方向に屈折率が変化する屈折率分布型
媒質から成る少なくとも2枚構成のレンズ系であって、
前記レンズ系の物体側レンズは少なくとも前記レンズの
第2面が平面であり、かつ前記レンズの焦点面が前記第
2面となるようなレンズ長を有しており、さらに特定の
空間周波数範囲の光を遮断し、他の周波数範囲の光の通
過を許す空間フィルタが前記レンズの第2面に接してあ
るいは直接設けてあり、前記レンズ系の像側レンズは少
なくとも第1面が平面であり、前記物体側レンズと前記
像側レンズは前記空間フィルタを介して接合されている
ことを特徴とする空間フィルタリングレンズ系。
1. A lens system having at least two lenses composed of a gradient index medium in which the refractive index changes in the radial direction,
The object side lens of the lens system has a lens length such that at least the second surface of the lens is a flat surface, and the focal plane of the lens is the second surface, A spatial filter that blocks light and allows passage of light in other frequency ranges is provided in contact with or directly on the second surface of the lens, and at least the first surface of the image side lens of the lens system is a flat surface, The spatial filtering lens system, wherein the object side lens and the image side lens are cemented via the spatial filter.
【請求項2】特許請求の範囲第1項において、前記空間
フィルタは、遮光部又は透光部の形状を可変とした空間
フィルタリングレンズ系。
2. The spatial filtering lens system according to claim 1, wherein the spatial filter has a variable shape of a light shielding portion or a light transmitting portion.
JP62002044A 1987-01-08 1987-01-08 Space filtering lens system Expired - Lifetime JP2545524B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62002044A JP2545524B2 (en) 1987-01-08 1987-01-08 Space filtering lens system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62002044A JP2545524B2 (en) 1987-01-08 1987-01-08 Space filtering lens system

Publications (2)

Publication Number Publication Date
JPS63169613A JPS63169613A (en) 1988-07-13
JP2545524B2 true JP2545524B2 (en) 1996-10-23

Family

ID=11518326

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62002044A Expired - Lifetime JP2545524B2 (en) 1987-01-08 1987-01-08 Space filtering lens system

Country Status (1)

Country Link
JP (1) JP2545524B2 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5775376B2 (en) * 2011-06-22 2015-09-09 日本放送協会 3D display device

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61137125A (en) * 1984-12-07 1986-06-24 Canon Inc Optical information processor

Also Published As

Publication number Publication date
JPS63169613A (en) 1988-07-13

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