JPH0310925B2 - - Google Patents

Info

Publication number
JPH0310925B2
JPH0310925B2 JP10960480A JP10960480A JPH0310925B2 JP H0310925 B2 JPH0310925 B2 JP H0310925B2 JP 10960480 A JP10960480 A JP 10960480A JP 10960480 A JP10960480 A JP 10960480A JP H0310925 B2 JPH0310925 B2 JP H0310925B2
Authority
JP
Japan
Prior art keywords
group
lens
screen
optical system
refractive power
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
Application number
JP10960480A
Other languages
Japanese (ja)
Other versions
JPS5734515A (en
Inventor
Kazuo Yamakawa
Toshihide Doi
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.)
Minolta Co Ltd
Original Assignee
Minolta 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 Minolta Co Ltd filed Critical Minolta Co Ltd
Priority to JP10960480A priority Critical patent/JPS5734515A/en
Priority to US06/347,032 priority patent/US4577935A/en
Publication of JPS5734515A publication Critical patent/JPS5734515A/en
Publication of JPH0310925B2 publication Critical patent/JPH0310925B2/ja
Granted legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/18Optical objectives specially designed for the purposes specified below with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/16Optical objectives specially designed for the purposes specified below for use in conjunction with image converters or intensifiers, or for use with projectors, e.g. objectives for projection TV
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B9/00Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or -
    • G02B9/12Optical objectives characterised both by the number of the components and their arrangements according to their sign, i.e. + or - having three components only

Description

【発明の詳細な説明】[Detailed description of the invention]

本発明は投写管画像をスクリーンに投写するビ
デオプロジエクターのための屈折型光学系に関す
るものであり、少ないレンズ構成枚数によりF値
が2より明るくかつ性能の良好な屈折型光学系を
提供することを目的とするものである。 本発明の構成は、第1及び第3図より明らかな
ように、スクリーン側より投写管側へ順に正屈折
力を有する単レンズの第1群、正屈折力を有し
その両側面がともに凸面である単レンズの第2群
、負屈折力を有しそのスクリーン側の面が凹面
である単レンズの第3群からなる3群構成であ
り、第1群から第3群のいずれかの群に平行平面
ガラス板を配置するとともに、下記の条件を満足
することを特徴とするビデオプロジエクター用屈
折型光学系である。 (1) 1.2f<f1<2.5f 但し、fは全体の焦点距離、 f1は前記第1群の焦点距離である。 また、本発明のより詳細な特徴は、上記条件1
に加えさらに下記の条件を満足することである。 (2) 1.2<f1/f2<2.5 但し、f2は前記第2群の焦点距離である。 なお、本発明の実施にあたつてはさらに、下記
の条件を満足することが特徴である。 (3) 0.3f<D<0.5f 但し、Dは前記第2群と第3群との間の空気間
隔である。 次に本発明の条件式について説明する。条件(1)
は第1群への屈折力の配分を規定し、条件(2)は、
正の屈折力を担う第1群と第2群との間の相対的
な屈折力配分を規定するものである。すなわち、
第1群に比較的大きな正の屈折力を与え、レンズ
系中の正の屈折力を第1群と第2群とで適度に分
担することによつて、軸上及び軸外の収差補正の
バランスをとるとともに、レンズ全長を短くし、
全系をコンパクトに構成するのが、条件(1)(より
詳細には条件(1)と条件(2)との組み合わせ)に表わ
される本発明の特徴である。条件(1)又は(2)の下限
を外れるときには、第1群のパワーが強くなり過
ぎることによつて高次の球面収差の発生と像面湾
曲の負偏移をきたす。一方条件(1)又は(2)の上限を
外れると像面湾曲が補正過剰となり、また軸外の
サジタルフレアーが発生する。いずれの場合も軸
上及び軸外での収差の均衝がとれず明るく高性能
なレンズ系としての構成が困難となる。 条件(3)は第2群と第3群の空気間隔を与えるも
ので第1群と第2群のパワー配分において最適と
なる範囲を決めるべきものである。条件(3)の下限
を外れると像面湾曲の負偏移とともに非点隔差が
拡大される。一方条件(3)の上限を外れるとサジタ
ルのフレアーが補正不足になるとともに第3群と
被写管との距離が極端に近づくため実用上不都合
である。 更に本発明においては、収差をより良好に補正
するために少なくとも第1群の一つの屈折面に非
球面を導入することが特徴である。 次に本発明の実施例を示す。以下の記述におい
てr1,r2……はレンズ各面の曲率半径、d1,d2
…はレンズ面間の肉厚または空気間隔、n1,n2
…は各レンズのd線(波長587.6nmの光)に対す
る屈折率、ν1,ν2……はd線に対するアツベ数で
ある(すべてスクリーン側から投写管側への順)。
また、非球面形状を有する面(※印で表示)につ
いては、その面の頂点から光軸上に投与管方向を
正とするX軸をとり、同頂点にX軸と垂直なY軸
をとるとき非球面形状を次の式にて表わす。 X=C0Y2/1+(1−C0 2Y21/28i=1 CiY2i なおこの式はC1Y2の項を含んだ表現であるため
この式で表わされる非球面の近軸曲率は、C0
2C1となつている。(但しC0=1/r:rは球面
としての曲率半径) 〔実施例 1〕
The present invention relates to a refractive optical system for a video projector that projects a projection tube image onto a screen, and an object of the present invention is to provide a refractive optical system that has an F value brighter than 2 and has good performance with a small number of lenses. The purpose is to As is clear from FIGS. 1 and 3, the configuration of the present invention consists of a first group of single lenses having positive refractive power in order from the screen side to the projection tube side; It has a three-group configuration consisting of a second group of single lenses, which has a negative refractive power, and a third group of single lenses whose screen-side surface is concave, and any of the first to third groups. This is a refractive optical system for a video projector, characterized in that a parallel plane glass plate is disposed in the periphery, and the following conditions are satisfied. (1) 1.2f<f 1 <2.5f where f is the overall focal length, and f 1 is the focal length of the first group. Further, the more detailed characteristics of the present invention are as follows.
In addition to this, the following conditions must also be satisfied. (2) 1.2<f 1 /f 2 <2.5 where f 2 is the focal length of the second group. In addition, the present invention is further characterized in that the following conditions are satisfied. (3) 0.3f<D<0.5f where D is the air distance between the second group and the third group. Next, the conditional expression of the present invention will be explained. Condition 1)
defines the distribution of refractive power to the first group, and condition (2) is
This defines the relative distribution of refractive power between the first group and the second group, which bear positive refractive power. That is,
By giving relatively large positive refractive power to the first group and appropriately sharing the positive refractive power in the lens system between the first and second groups, on-axis and off-axis aberrations can be corrected. In addition to achieving balance, the overall length of the lens is shortened,
A feature of the present invention expressed in condition (1) (more specifically, the combination of condition (1) and condition (2)) is that the entire system is configured compactly. When the lower limit of condition (1) or (2) is exceeded, the power of the first group becomes too strong, resulting in generation of high-order spherical aberration and negative shift of the curvature of field. On the other hand, if the upper limit of condition (1) or (2) is exceeded, the curvature of field will be overcorrected and off-axis sagittal flare will occur. In either case, the on-axis and off-axis aberrations are not balanced, making it difficult to construct a bright and high-performance lens system. Condition (3) gives the air spacing between the second and third groups, and should determine the optimum range for power distribution between the first and second groups. When the lower limit of condition (3) is exceeded, the astigmatism difference increases as the field curvature shifts negatively. On the other hand, if the upper limit of condition (3) is exceeded, sagittal flare will be insufficiently corrected and the distance between the third group and the subject tube will become extremely close, which is inconvenient in practice. Furthermore, the present invention is characterized in that an aspherical surface is introduced into at least one refractive surface of the first group in order to better correct aberrations. Next, examples of the present invention will be shown. In the following description, r 1 , r 2 ... are the radius of curvature of each surface of the lens, d 1 , d 2 ...
... is the wall thickness or air gap between lens surfaces, n 1 , n 2 ...
... is the refractive index of each lens for the d-line (light with a wavelength of 587.6 nm), and ν 1 , ν 2 ... are the Abbe numbers for the d-line (all in order from the screen side to the projection tube side).
For surfaces with an aspherical shape (indicated by *), the X-axis with the administration tube direction as positive is taken from the apex of the surface on the optical axis, and the Y-axis perpendicular to the X-axis is taken at the same apex. The aspherical shape is expressed by the following equation. X=C 0 Y 2 /1+(1-C 0 2 Y 2 ) 1/2 + 8i=1 CiY 2iThis equation includes the term C 1 Y 2 , so it is expressed as this equation. The paraxial curvature of an aspheric surface is C 0 +
2C 1 . (However, C 0 = 1/r: r is the radius of curvature as a spherical surface) [Example 1]

【表】 〔実施例 2〕【table】 [Example 2]

【表】【table】

【表】 上記実施例1のレンズ構成図を第1図に示す。
第1図より明らかなように、本実施例では第1群
はスクリーン側に凸の平凸プラスチツク単レンズ
L1及びその投与管側に配される平行平面ガラス
板Xより成り、前記第2群は両凸のプラスチツク
単レンズL2より成るとともに、前記第3群はス
クリーン側に凹面を向けた負屈折力のプラスチツ
ク単レンズL3より成る。なお、Pは、L3から11.4
隔てて配される厚さ7.2(n=1.538,νd=57.5)の
投写管フエースプレートであり、その図面右側面
が蛍光面となつている。また、上記平行面ガラス
板Xは投写管より発せられるX線を遮蔽するため
のものである。上記実施例1の収差図を第2図に
示す。 第3図は盾記実施例2のレンズ構成図である。
第3図より明らかなように、実施例2では第1群
はスクリーン側に凸面を向けた正屈折力のプラス
チツク単レンズL1より成り、前記第2群は両凸
のプラスチツク単レンズL2より成るとともに、
前記第3群はスクリーン側に凹の平凹プラスチツ
ク単レンズL3及びその投与管側に配されるX線
遮蔽用平行平面ガラス板Xより成る。フエースプ
レートPは厚さ5.0(n=1.538,νd=57.5)であ
り、Xから15.9隔てて配されている。実施例2の
収差図を第4図に示す。 以上から明らかなように、本発明は少ないレン
ズ構成枚数でF値が明るく、かつ収差図に示すよ
うに性能の良好な屈折型光学系をビデオプロジエ
クターのために提供するものである。
[Table] FIG. 1 shows a lens configuration diagram of Example 1.
As is clear from Fig. 1, in this example, the first group is a single plano-convex plastic lens convex toward the screen.
The second group consists of a biconvex plastic single lens L2 , and the third group consists of a negative refractive lens with a concave surface facing the screen side. Consists of a single plastic lens L3 . In addition, P is L 3 to 11.4
These are projection tube face plates with a thickness of 7.2 (n=1.538, νd=57.5) placed apart from each other, and the right side of the projection tube is a fluorescent screen. Further, the parallel glass plate X is for shielding X-rays emitted from the projection tube. FIG. 2 shows an aberration diagram of the first embodiment. FIG. 3 is a lens configuration diagram of Example 2 of the shield.
As is clear from FIG. 3, in Embodiment 2, the first group consists of a single plastic lens L1 with positive refractive power with its convex surface facing the screen, and the second group consists of a single plastic lens L2 with a double convex surface. Along with becoming
The third group consists of a concave plano-concave plastic single lens L3 concave on the screen side and a parallel plane glass plate X for X-ray shielding disposed on the administration tube side. The face plate P has a thickness of 5.0 (n=1.538, vd=57.5) and is spaced apart from X by 15.9. FIG. 4 shows an aberration diagram of Example 2. As is clear from the above, the present invention provides a refractive optical system for a video projector that has a small number of lenses, has a bright F value, and has good performance as shown in the aberration diagram.

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

第1図は本発明の実施例1のレンズ構成図、第
2図は上記実施例1の収差図、第3図及び第4図
は、それぞれ本発明の実施例2のレンズ構成図及
び収差図である。 ……第1群、……第2群、……第3群。
FIG. 1 is a lens configuration diagram of Example 1 of the present invention, FIG. 2 is an aberration diagram of the above-mentioned Example 1, and FIGS. 3 and 4 are lens configuration diagrams and aberration diagrams of Example 2 of the present invention, respectively. It is. ...First group, ...Second group, ...Third group.

Claims (1)

【特許請求の範囲】 1 スクリーン側より投写管側へ順に正屈折力を
有する単レンズの第1群、正屈折力を有しその両
側面がともに凸面である単レンズの第2群、負屈
折力を有しそのスクリーン側の面が凹面である単
レンズの第3群からなる3群構成であり、少なく
とも第1群の1つの屈折面が非球面であり、第1
群から第3群のいずれかの群に平行平面ガラス板
を配置するとともに、下記の条件を満足すること
を特徴とするF値が2より明るいビデオプロジエ
クター用屈折型光学系: 1.2f<f1<2.5f 0.3f<D<0.5f ただし、 f:全系の焦点距離、 f1:第1群の焦点距離、 D:第2群と第3群との間の空気間隔。 2 さらに、下記の条件を満足することを特徴と
する特許請求の範囲第1項記載の屈折型光学系: 1.2<f1/f2>2.5 ただし、 f2:第2群の焦点距離。 3 前記第1群の投写管側の面が平面であること
を特徴とする特許請求の範囲第1項または第2項
いずれかに記載の屈折型光学系。 4 前記第1群はスクリーン側に凸の平凸プラス
チツク単レンズ及びその投写管側に配された平行
平面板、前記第2群は両凸のプラチツク単レン
ズ、前記第3群はスクリーン側に凹面を向けた負
屈折力のプラスチツク単レンズより成ることを特
徴とする特許請求の範囲第1項から第3項までの
いずれかに記載の屈折型光学系。 5 前記第1群はスクリーン側に凸面を向けた正
屈折力のプラスチツク単レンズ、前記第2群は両
凸のプラスチツク単レンズ、前記第3群はスクリ
ーン側に凹の平凹プラスチツク単レンズ及びその
投写管側配された平行平面板より成ることを特徴
とする特許請求の範囲第1項から第3項までのい
ずれかに記載の屈折型光学系。
[Claims] 1. A first group of single lenses having positive refractive power in order from the screen side to the projection tube side, a second group of single lenses having positive refractive power whose both sides are convex, and negative refractive power. It has a three-group configuration consisting of a third group of a single lens having a concave surface on the screen side, and at least one refractive surface of the first group is an aspherical surface.
A refractive optical system for a video projector with an F value brighter than 2, characterized in that a parallel plane glass plate is arranged in any group from the third group to the third group, and the following conditions are satisfied: 1.2f<f 1 <2.5f 0.3f<D<0.5f where f: focal length of the entire system, f 1 : focal length of the first group, D: air distance between the second and third groups. 2. The refractive optical system according to claim 1, further satisfying the following conditions: 1.2<f 1 /f 2 >2.5, where f 2 : focal length of the second group. 3. The refractive optical system according to claim 1 or 2, wherein the surface of the first group on the projection tube side is a flat surface. 4 The first group is a single plano-convex plastic lens with a convex surface facing the screen and a parallel plane plate placed on the projection tube side, the second group is a single plastic lens with a biconvex surface, and the third group is a single lens with a concave surface facing the screen. A refractive optical system according to any one of claims 1 to 3, characterized in that the refractive optical system comprises a single plastic lens with a negative refractive power directed toward the refractive power. 5. The first group is a plastic single lens with positive refractive power with a convex surface facing the screen, the second group is a biconvex plastic single lens, and the third group is a plano-concave plastic single lens with a concave surface facing the screen, and the like. A refractive optical system according to any one of claims 1 to 3, characterized in that it comprises a parallel plane plate placed on the side of a projection tube.
JP10960480A 1980-03-03 1980-08-09 Refracting index type optical system for video projector Granted JPS5734515A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
JP10960480A JPS5734515A (en) 1980-08-09 1980-08-09 Refracting index type optical system for video projector
US06/347,032 US4577935A (en) 1980-03-03 1982-02-08 Video projector lens system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP10960480A JPS5734515A (en) 1980-08-09 1980-08-09 Refracting index type optical system for video projector

Publications (2)

Publication Number Publication Date
JPS5734515A JPS5734515A (en) 1982-02-24
JPH0310925B2 true JPH0310925B2 (en) 1991-02-14

Family

ID=14514487

Family Applications (1)

Application Number Title Priority Date Filing Date
JP10960480A Granted JPS5734515A (en) 1980-03-03 1980-08-09 Refracting index type optical system for video projector

Country Status (1)

Country Link
JP (1) JPS5734515A (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58125007A (en) * 1982-01-20 1983-07-25 Matsushita Electric Ind Co Ltd Projection lens
JPS58181009A (en) * 1982-04-16 1983-10-22 Matsushita Electric Ind Co Ltd Projection lens
JPS58198017A (en) * 1982-05-15 1983-11-17 Hitachi Ltd Projection lens
JPS58220115A (en) * 1982-06-17 1983-12-21 Canon Inc Wide angle lens system
JPS59133518A (en) * 1983-01-20 1984-07-31 Matsushita Electric Ind Co Ltd Optical path bending type projection lens
JPS59133517A (en) * 1983-01-21 1984-07-31 Nippon Kogaku Kk <Nikon> Projection lens
JPS6067914A (en) * 1983-09-22 1985-04-18 Konishiroku Photo Ind Co Ltd Projection lens for television projector
JPS6073514A (en) * 1983-09-30 1985-04-25 Hitachi Ltd Lens for projection television
JPS60177478U (en) * 1984-05-07 1985-11-25 日本電気株式会社 table tap
JP2617908B2 (en) * 1984-09-27 1997-06-11 松下電器産業株式会社 Projection optics
JPH0627895B2 (en) * 1984-12-20 1994-04-13 松下電器産業株式会社 Projection lens
US4690515A (en) * 1984-12-20 1987-09-01 Matsushita Electric Industrial Co., Ltd. Compact projection lens
JPH0627896B2 (en) * 1985-02-06 1994-04-13 松下電器産業株式会社 Projection lens
NL8500453A (en) * 1985-02-18 1986-09-16 Philips Nv PROJECTIVE SYSTEM.

Also Published As

Publication number Publication date
JPS5734515A (en) 1982-02-24

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