JPH0411007B2 - - Google Patents
Info
- Publication number
- JPH0411007B2 JPH0411007B2 JP6882283A JP6882283A JPH0411007B2 JP H0411007 B2 JPH0411007 B2 JP H0411007B2 JP 6882283 A JP6882283 A JP 6882283A JP 6882283 A JP6882283 A JP 6882283A JP H0411007 B2 JPH0411007 B2 JP H0411007B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- plane
- cylindrical
- cross
- spherical
- 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
Links
- 230000004907 flux Effects 0.000 claims description 5
- 230000003287 optical effect Effects 0.000 claims 1
- 238000009434 installation Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B13/00—Optical objectives specially designed for the purposes specified below
- G02B13/08—Anamorphotic objectives
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B3/00—Simple or compound lenses
- G02B3/02—Simple or compound lenses with non-spherical faces
- G02B3/06—Simple or compound lenses with non-spherical faces with cylindrical or toric faces
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Mechanical Optical Scanning Systems (AREA)
- Lenses (AREA)
Description
本発明は、球面と円筒面よりなる２枚構成トー
リツクレンズに関するものである。
ｆ−θレンズと回転多面鏡との結合によるレー
ザー走査型のプリンター等において、多面鏡の面
倒れ誤差、回転軸のアンギユラーモーシヨン、及
び多面鏡と回転軸の取り付け誤差等によつて生ず
る描画精度への悪影響を避けるため、もしくは軽
減させるために、トロイダルレンズを使用する方
法は知られている。そこで本発明は、該トロイダ
ルレンズを、高精度で加工、組み立てができ、し
かも高い生産性を実現できるような、球面と円筒
面よりなる２枚構成トーリツクレンズとして提供
することを目的とする。
ここで、トロイダルレンズを便宜上２つの円環
面より成るレンズと定義し、トーリツクレンズを
一方の面が球面で他方の面が円筒面より成るレン
ズと定義する。また、円環面とは円柱の軸を円に
沿つて曲げた場合に生ずる円柱表面を言うことと
する。
ｆ−θレンズと回転多面鏡との結合によるレー
ザー走査型のプリンター又はプロツターにおい
て、多面鏡の面倒れ誤差、回転軸の振れ、及び多
面鏡と回転軸の取り付け誤差等の影響を除くため
に、多面鏡に入射する前にビームをシリンドリカ
ルレンズに入射させて、多面鏡の鏡面上で線状の
偏平光束とし、多面鏡からの反射ビームを、トロ
イダルレンズに入れることにより元の円形平行光
束に戻し、その後にｆ−θレンズに入射させるこ
とは有効であり知られている。即ち、これは、光
が走査されるXZ面内でのみ考えれば、多面鏡の
鏡面上の点（第１図Ｏ点）と、ｆ−θレンズの像
面上の点とを共役関係にすることによつて、多面
鏡の鏡面の理想垂直面からの面振れの影響を除去
するものである。
この時、多面鏡によつて反射したのビームを受
けるトロイダルレンズは、一般には２つの円環面
より成るレンズであり、円環面に於ては、第１
図、第２図の座標軸を用いて言うと、XY面内の
曲率半径とXZ面内の曲率半径とが大きく異るた
めに、製作精度は上らず、生産性は低く高価であ
り、なかなか精度上満足のいくものは得られなか
つた。
しかしながら、本発明では、研究の結果、先ず
トロイダルレンズを１枚構成ではなく２枚構成と
し、度を２枚に分離することによつて各レンズの
度を下げ、これによつて同時に各レンズの一方の
面の、XY面内の曲率半径とXZ面内の曲率半径
との差を小さくし、即ち最終的には球面とし、ま
た他方の面は、場合によつては硝材の屈折率を適
当に選択する必要が生ずるが、円筒面とすること
が可能であり、こうして、２枚構成の各レンズ
が、一面は円筒面、一面は球面のトーリツクレン
ズで、しかもこの時このトーリツクレンズ系の前
側焦点は４つの曲面の共通中心点上にあるように
出来、全系で所望のトロイダルレンズの仕様を満
たすトーリツクレンズ系が可能であることが判明
した。加えて、これにより、円環面という、製作
上極めて困難な、従つて加工精度も上らず、生産
性も上らない曲面を用いることなく、円筒面と球
面という、加工上極めて安価で、精度も上り、生
産性の高いレンズ系が可能となつた。
かくして本発明における２枚構成トーリツクレ
ンズは、光の入射側から、第１面が円筒面で第２
面が球面である第１レンズと、第３面が円筒面で
第４面が球面である第２レンズとから成り、XY
断面内の２つの球面の中心と２つの円筒面の中心
とが共通な１点上にあるようになし、XZ断面内
の光束に対してのみ度を持ち、XY断面内の光束
に対しては殆ど度を持たないようにし、且つXZ
断面内の前側焦点をXY断面内の４つの曲面の共
通中心点上に持つように構成したものである。光
は、XY断面方向に走査される。
更に、本発明の実施例におけるレンズ系の、
XZ面内断面図を第１図に、XY面内断面図を第
２図に示したが、この実施例の諸元は次のとおり
である。
The present invention relates to a two-element Tory lens consisting of a spherical surface and a cylindrical surface. In laser scanning printers that combine an f-theta lens and a rotating polygon mirror, drawings occur due to errors in the surface tilt of the polygon mirror, angular motion of the rotation axis, and installation errors between the polygon mirror and the rotation axis. It is known to use toroidal lenses to avoid or reduce the negative impact on accuracy. Therefore, an object of the present invention is to provide a two-piece toroidal lens consisting of a spherical surface and a cylindrical surface, which can be processed and assembled with high precision and achieve high productivity. Here, for convenience, a toroidal lens is defined as a lens consisting of two toric surfaces, and a toroidal lens is defined as a lens where one surface is a spherical surface and the other surface is a cylindrical surface. Furthermore, a toric surface refers to a cylindrical surface that is created when the axis of a cylinder is bent along a circle. In a laser scanning printer or plotter that combines an f-theta lens and a rotating polygon mirror, in order to eliminate the effects of surface tilt errors of the polygon mirror, runout of the rotation axis, and installation errors between the polygon mirror and the rotation axis, Before entering the polygon mirror, the beam enters a cylindrical lens to form a linear flat beam on the mirror surface of the polygon mirror, and the reflected beam from the polygon mirror is returned to the original circular parallel beam by entering it into a toroidal lens. , and then making the light incident on an f-theta lens is effective and known. That is, if we consider only within the XZ plane where the light is scanned, the point on the mirror surface of the polygon mirror (point O in Figure 1) and the point on the image plane of the f-theta lens are in a conjugate relationship. This eliminates the influence of surface deflection from the ideal vertical plane of the mirror surface of the polygon mirror. At this time, the toroidal lens that receives the beam reflected by the polygon mirror is generally a lens consisting of two toric surfaces.
Using the coordinate axes in Figures and Figure 2, the radius of curvature in the XY plane and the radius of curvature in the Satisfactory accuracy could not be obtained. However, in the present invention, as a result of research, firstly, the toroidal lens is made of two lenses instead of one, and the power of each lens is lowered by separating the power into two lenses. The difference between the radius of curvature of one surface in the XY plane and the radius of curvature in the However, it is possible to select a cylindrical surface, and in this way, each lens of the two-element structure is a Torytsu lens with one surface being a cylindrical surface and the other being a spherical surface. It has been found that it is possible to create a toroidal lens system in which the focal point is located on the common center point of the four curved surfaces, and the entire system satisfies the desired toroidal lens specifications. In addition, this eliminates the need to use a toric surface, which is extremely difficult to manufacture, and therefore does not improve machining accuracy or productivity, and instead creates cylindrical and spherical surfaces, which are extremely inexpensive to process. Accuracy has also improved, making it possible to create lens systems with high productivity. In this way, the two-piece Toric lens of the present invention has a first surface that is a cylindrical surface and a second surface that is a cylindrical surface from the light incident side.
It consists of a first lens whose surface is a spherical surface, and a second lens whose third surface is a cylindrical surface and whose fourth surface is a spherical surface.
The centers of the two spherical surfaces and the centers of the two cylindrical surfaces in the cross section are located on a common point, and it has a degree only for the luminous flux in the XZ cross section, and for the luminous flux in the XY cross section. Almost no degree, and XZ
The front focal point in the cross section is located on the common center point of the four curved surfaces in the XY cross section. The light is scanned in the XY cross-sectional direction. Furthermore, the lens system in the embodiment of the present invention,
A sectional view in the XZ plane is shown in FIG. 1, and a sectional view in the XY plane is shown in FIG. 2. The specifications of this embodiment are as follows.
【表】
但し、r1は第ｉ面のXZ面内曲率半径、rYiは第
ｉ面のXY面内曲率半径、diは第ｉ番目のレンズ
厚又は空気間隔、njは第ｊレンズのｄ−lineの屈
折率、νj第ｊレンズのｄ−lineのアツベ数とする。
この２枚構成トーリツクレンズは、XZ面内前
側焦点を、回転多面鏡の鏡面上に置くように配置
してプリンターやプロツターに用いられる。つま
り、光は、XZ面内において、本２枚構成トーリ
ツクレンズに入射し走査される。
また、当該２枚構成トーリツクレンズは、XY
断面内の光束に対して、或る有限のレンズ厚みを
持つため、実際には僅かの負の度を持つ。このた
め平行入射した光束はレンズ透過後XY断面内で
僅かに拡散する光束となる。これが問題となる場
合には、次の手法が有効である。即ち、回転多面
鏡の反射面の前に置かれたシリンドリカルレンズ
の代りに、本発明による２枚構成トーリツクレン
ズを採用する。勿論この場合はレーザービームが
多面鏡に入射する前であるからXY面内のレンズ
の大きさは、空間に静止した平行光束をカバーす
るだけの大きさで良い。ここで、便宜上、この反
射前に置かれるレンズを小トーリツクと称し、反
射後に置かれるレンズを大トーリツクと称する
と、この小トーリツクの場合は、XY面内の４つ
の曲面の中心点の共通点（第２図Ｏ点）から、２
つの円筒面のうちどちらか一方の中心を故意にず
らすことにより、該小トーリツクにXY面内の僅
かな正の度を持たせ、その度は、光束が回転多面
鏡で反射し大トーリツクを通過後に丁度平行光束
に戻るような度にする。これによつて、大トーリ
ツク通過後のXY面内光束を平行にすることが可
能である。
以上説明したように本発明によれば、ｆ−θレ
ンズと回転多面鏡とによるレーザースキヤン型プ
ロツター等の、多面鏡面倒れ、回転軸振れ及び多
面鏡と回転軸の取り付け誤差等の影響除去のため
のトロイダルレンズとして、球面と円筒面とから
なる２枚構成のトーリツクレンズを用いることが
できることが判明した。しかるに、そのトーリツ
クレンズは、球面と円筒面という極めて製作容易
な面で構成されるため、精度上の到達度が高度に
なり、より高精度な面での要求に応えることが可
能となり、また一方では高い生産性が期待される
ため安価な普及型にも採用可能性を拓いた。[Table] However, r 1 is the radius of curvature of the i-th surface in the XZ plane, r Yi is the radius of curvature of the i-th surface in the XY plane, d i is the thickness or air gap of the i-th lens, and n j is the j-th lens. Let ν j be the refractive index of the d-line of the j-th lens, and the Abbe number of the d-line of the j-th lens. This two-element toric lens is used in printers and plotters by placing the front focus in the XZ plane on the mirror surface of a rotating polygon mirror. In other words, the light enters the two-element Toric lens in the XZ plane and is scanned. In addition, the two-element Torytsu lens is
Since the lens has a certain finite thickness with respect to the light beam within the cross section, it actually has a slight negative power. Therefore, the parallel incident light beam becomes a light beam that is slightly diffused within the XY cross section after passing through the lens. If this is a problem, the following method is effective. That is, instead of the cylindrical lens placed in front of the reflecting surface of the rotating polygon mirror, a two-piece toric lens according to the present invention is used. Of course, in this case, the laser beam is before it enters the polygon mirror, so the size of the lens in the XY plane only needs to be large enough to cover the parallel light flux that is stationary in space. For convenience, the lens placed before this reflection is referred to as a small torque, and the lens placed after reflection is referred to as a large torque.In the case of this small torque, there is a common point between the centers of the four curved surfaces in the XY plane. From (point O in Figure 2), 2
By intentionally shifting the center of one of the two cylindrical surfaces, the small toric has a slight positive degree in the XY plane, and at that degree, the light beam is reflected by the rotating polygon mirror and passes through the large toric. Adjust the angle so that the beam returns to a parallel beam later. With this, it is possible to make the light beam in the XY plane parallel after passing through the large toric. As explained above, according to the present invention, in a laser scan type plotter using an f-theta lens and a rotating polygon mirror, the influence of polygon mirror surface inclination, rotation axis runout, and installation error between the polygon mirror and the rotation axis can be eliminated. It has been found that a two-lens toroidal lens consisting of a spherical surface and a cylindrical surface can be used as the toroidal lens. However, since the Torytsu lens is composed of spherical and cylindrical surfaces, which are extremely easy to manufacture, it has a high level of accuracy and can meet the demands for higher precision surfaces. Since it is expected to have high productivity, it has opened up the possibility of adoption in inexpensive popular models.
第１図、第２図はそれぞれ本発明実施例におけ
るレンズ系のXZ面内断面図及びXY面内断面図
である。
FIGS. 1 and 2 are a cross-sectional view in the XZ plane and a cross-sectional view in the XY plane, respectively, of a lens system according to an embodiment of the present invention.
Claims (1)
球面である第１レンズと、第３面が円筒面で第４
面が球面である第２レンズとから成り、 XY断面内の２つの球面の中心と２つの円筒面
の中心が共通な１点上にあるようになして、XZ
断面内の光束に対してのみ度を持ち、XY断面内
の光束に対しては殆ど度を持たないようにすると
ともに、 XZ断面内の前側焦点をXY断面内の４つの曲
面の共通中心点上に持つようになし、 且つXY断面方向を光走査方向としたことを特
徴とする、球面と円筒面よりなる２枚構成トーリ
ツクレンズ。 ２ 次の諸元をもつ特許請求の範囲第１項に記載
の２枚構成トーリツクレンズ。 【表】 但し、r1は第ｉ面のXZ面内曲率半径、rYiは第
ｉ面のXY面内曲率半径、diは第ｉ番目のレンズ
厚又は空気間隔、njは第ｊレンズのｄ−lineの屈
折率、νjは第ｊレンズのｄ−lineのアツベ数とす
る。[Claims] 1. From the light incident side, there is a first lens whose first surface is a cylindrical surface and a second surface which is a spherical surface, and a fourth lens whose third surface is a cylindrical surface.
and a second lens whose surface is a spherical surface, so that the centers of the two spherical surfaces and the centers of the two cylindrical surfaces in the
It has power only for the light flux within the cross section, and has almost no power for the light flux within the XY cross section, and the front focal point in the A two-element Torytsu lens consisting of a spherical surface and a cylindrical surface, characterized in that it is held in such a way as to be held in the same direction, and the XY cross-sectional direction is the optical scanning direction. 2. A two-piece Toric lens according to claim 1 having the following specifications. [Table] However, r 1 is the radius of curvature of the i-th surface in the XZ plane, r Yi is the radius of curvature of the i-th surface in the XY plane, d i is the thickness or air gap of the i-th lens, and n j is the j-th lens. The refractive index of the d-line, ν j , is the Abbe number of the d-line of the j-th lens.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6882283A JPS59195210A (en) | 1983-04-19 | 1983-04-19 | Toric lens having dual structure consisting of spherical surface and cylindrical surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6882283A JPS59195210A (en) | 1983-04-19 | 1983-04-19 | Toric lens having dual structure consisting of spherical surface and cylindrical surface |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS59195210A JPS59195210A (en) | 1984-11-06 |
| JPH0411007B2 true JPH0411007B2 (en) | 1992-02-27 |
Family
ID=13384785
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6882283A Granted JPS59195210A (en) | 1983-04-19 | 1983-04-19 | Toric lens having dual structure consisting of spherical surface and cylindrical surface |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS59195210A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2716428B2 (en) * | 1986-07-14 | 1998-02-18 | ミノルタ株式会社 | Surface tilt correction scanning optical system |
| US4919502A (en) * | 1986-07-14 | 1990-04-24 | Minolta Camera Kabushiki Kaisha | Tilt error corrective scanning optical system |
| USRE34438E (en) * | 1986-07-14 | 1993-11-09 | Minolta Camera Kabushiki Kaisha | Tilt error corrective scanning optical system |
| EP2605284A4 (en) * | 2010-08-13 | 2014-06-25 | Optoelectronics Co Ltd | Optical detecting device, optical device, optical information reading device, and light source affixing method |
-
1983
- 1983-04-19 JP JP6882283A patent/JPS59195210A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS59195210A (en) | 1984-11-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3467193B2 (en) | Refractive / reflective fθ optical element and scanning optical system | |
| US4900138A (en) | Composite gradient index and curved surface anamorphic lens and applications | |
| JPH06230308A (en) | Light beam scanning device | |
| US4984858A (en) | Light beam scanning optical system | |
| JPS63316821A (en) | Optical scanner | |
| JPH03116112A (en) | Scanning type optical device | |
| JPH0411007B2 (en) | ||
| EP0629891B1 (en) | Beam scanning apparatus | |
| JPH07174997A (en) | Optical scanner | |
| US5148304A (en) | Optical beam scanning system | |
| JPH07174998A (en) | Scanning lens and optical scanner | |
| KR920005033B1 (en) | Post objective optical deflector | |
| EP0018787A1 (en) | Optical scanning apparatus | |
| JP2722633B2 (en) | Laser scanning optical system | |
| JP3100761B2 (en) | Scanning optical system with temperature compensation | |
| JP3385678B2 (en) | Optical scanning device | |
| JP3483834B2 (en) | Optical scanning device | |
| JP3411661B2 (en) | Scanning optical system | |
| JP3381333B2 (en) | Optical scanning device | |
| JP2945247B2 (en) | Optical scanning optical system | |
| JP3331856B2 (en) | Laser light scanning device | |
| JP2530351B2 (en) | Post-objective optical scanning device | |
| JPH0786595B2 (en) | Post-objective optical scanning device | |
| JPH02157809A (en) | High resolution scanning optical system | |
| JPH05196885A (en) | Laser-beam scanning apparatus of optical system |