JPH0734065B2 - Focusing lens used in optical scanning device - Google Patents
Focusing lens used in optical scanning deviceInfo
- Publication number
- JPH0734065B2 JPH0734065B2 JP61098323A JP9832386A JPH0734065B2 JP H0734065 B2 JPH0734065 B2 JP H0734065B2 JP 61098323 A JP61098323 A JP 61098323A JP 9832386 A JP9832386 A JP 9832386A JP H0734065 B2 JPH0734065 B2 JP H0734065B2
- Authority
- JP
- Japan
- Prior art keywords
- lens
- scanning direction
- focusing lens
- main scanning
- curvature
- 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
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- Mechanical Optical Scanning Systems (AREA)
- Lenses (AREA)
Description
【発明の詳細な説明】 「産業上の利用分野」 本発明は光走査装置に用いる集束レンズに係り、特に変
調されたビームを走査する偏向器と記録媒体間に介在さ
せるｆθレンズ、面倒れ補正レンズその他の各種集束レ
ンズに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focusing lens used in an optical scanning device, and more particularly to an fθ lens interposed between a deflector for scanning a modulated beam and a recording medium, and surface tilt correction. Lenses and various other focusing lenses.
「従来の技術」 従来より例えば第２図に示す如く、ビーム発振器１より
発振された、入力情報に応じて変調されたレーザビーム
をコリメートレンズ２等を通して主走査方向に平行な線
状集束光として回転多面鏡その他の偏向器３に入射さ
せ、該偏向器３の回転により所定角度偏向反射されなが
らｆθレンズ４で等速運動に変換させた後、面倒れ補正
レンズ６により前記偏向器３の偏向面3aの副走査方向の
面倒れを補正して被記録媒体５の母線上に入力情報に対
応した光ドットパターンを結像走査させる光走査装置は
既に公知である。“Prior Art” Conventionally, as shown in FIG. 2, for example, a laser beam oscillated by a beam oscillator 1 and modulated according to input information is converted into linear focused light parallel to a main scanning direction through a collimator lens 2 and the like. The light is made incident on a deflector 3 such as a rotary polygon mirror, and after being deflected and reflected by a predetermined angle by the rotation of the deflector 3, it is converted into a uniform velocity motion by the fθ lens 4, and then the deflector 3 is deflected by a surface tilt correction lens 6. An optical scanning device which corrects the surface tilt of the surface 3a in the sub-scanning direction and forms an optical dot pattern corresponding to the input information on the generatrix of the recording medium 5 for image scanning is already known.
「発明が解決しようとする問題点」 そして前記面倒れ補正レンズ６には一般に主走査方向に
直線状に延設するシリンドリカルレンズを用いている
が、このようなシリンドリカルレンズを用いるレンズ長
手方向両端側の、該レンズに斜めに入射するビームに対
しては、該レンズの実効的曲率半径が小さくなり、焦点
距離の短いレンズとして作用する為に、第３図（Ａ）の
一点鎖線で示すように主走査方向に直交する方向（以下
副走査方向という）の像面が湾曲するという問題が発生
する。[Problems to be Solved by the Invention] Generally, a cylindrical lens linearly extending in the main scanning direction is used as the surface tilt correction lens 6, but both end sides in the lens longitudinal direction using such a cylindrical lens are used. For a beam obliquely incident on the lens, the effective radius of curvature of the lens becomes small and the lens acts as a lens having a short focal length. Therefore, as shown by the one-dot chain line in FIG. There is a problem that the image plane in the direction orthogonal to the main scanning direction (hereinafter referred to as the sub scanning direction) is curved.
かかる欠点を解消する為に、前記シリンドリカルレンズ
を長手方向（主走査方向）に沿ってｆθレンズ４側の入
射面が凸になるように僅かに曲げを与えたトーリックレ
ンズを用いる事により、第３図（Ｂ）上側グラフ図の一
点鎖線に示すように、前記副走査方向の像面湾曲が矯正
され、僅かに波形状になるも被記録面とほぼ合致させる
事が出来る。In order to eliminate such a drawback, by using a toric lens in which the cylindrical lens is slightly bent along the longitudinal direction (main scanning direction) so that the incident surface on the fθ lens 4 side is convex, As shown by the alternate long and short dash line in the upper graph of FIG. 6B, the curvature of field in the sub-scanning direction is corrected, and although it is slightly wavy, it can be almost matched with the recording surface.
一方、近年前記偏向器３の画角を拡げ、偏向面3aから被
記録媒体５母線までの焦点距離を短くし、装置全体の小
型化を図る試みがなされているが、このように焦点距離
が小さくなるに連れ、第３図（Ｂ）下側グラフ図の一点
鎖線に示すように、前記波形形状が増幅され、像面湾曲
が再度発生するという問題を有す。On the other hand, in recent years, it has been attempted to widen the angle of view of the deflector 3 and shorten the focal length from the deflecting surface 3a to the bus line of the recording medium 5 to reduce the size of the entire apparatus. As the size becomes smaller, there is a problem that the waveform shape is amplified and the field curvature is generated again, as shown by the alternate long and short dash line in the lower graph of FIG. 3 (B).
本発明はかかる従来技術の欠点に鑑み、面倒れ補正レン
ズとして適用した場合は、前記偏向器３の画角を拡げ、
焦点距離を短かくしつつも前記像面湾曲が発生する事が
なく、又ｆθレンズとして適用した場合は収差補正が可
能な、光走査装置に用いる集束レンズを提供する事にあ
る。In view of the drawbacks of the prior art, the present invention expands the angle of view of the deflector 3 when applied as a surface tilt correction lens,
It is an object of the present invention to provide a focusing lens used in an optical scanning device, which has a short focal length but does not cause the field curvature and can correct aberrations when applied as an fθ lens.
「発明の概要」 本発明はかかる技術的課題を達成する為に、偏向器３と
被記録媒体５間に介在させた面倒れ補正レンズ６やｆθ
レンズ４のビーム入射側切断形状が、主走査方向におけ
る中央位置とその両側位置で夫々曲率半径を異ならせた
事を必須構成要件とする技術手段を提案する。[Outline of the Invention] In order to achieve such a technical problem, the present invention provides a surface tilt correction lens 6 and fθ interposed between a deflector 3 and a recording medium 5.
A technical means is proposed in which the beam entrance side cutting shape of the lens 4 has different essential radii of curvature at the central position and the positions on both sides thereof in the main scanning direction.
このようなレンズは一般にはプラスチックレンズで形成
された、ビーム入射側を主走査方向に沿って凸に湾曲さ
せたシリンドリカルレンズ、トロイダルレンズ等のトー
リックレンズに適用される。Such a lens is generally applied to a toric lens such as a cylindrical lens or a toroidal lens, which is formed of a plastic lens and whose beam incident side is convexly curved along the main scanning direction.
又、前記切断形状の切断方向は主走査方向又は副走査方
向のいずれでもよく、第1A図に示すように、前記切断形
状が副走査方向に沿って切断された切断形状の場合は、
その曲率半径Ｒが主走査方向の中央位置Rcよりその両側
に進むに連れ徐々に大になり、そしてその途中に変移点
Rhで逆に徐々に小になるように設定するのがよく、 又第1B図に示すように、前記切断形状が主走査方向に沿
って切断された切断形状の場合は、その曲率半径Ｒが主
走査方向の中央位置Rc′よりその両側Rt′に進むに連れ
徐々に小になるように設定するのがよいが、 後者の場合はプラスチック成型型を用いて成型出来ず、
熱変形により成型しなければならない為に、量産には不
向きであり、一方前者の方は成型型で成型可能である為
に、量産に適し実用的である。Further, the cutting direction of the cutting shape may be either the main scanning direction or the sub-scanning direction, and as shown in FIG. 1A, when the cutting shape is a cutting shape cut along the sub-scanning direction,
The radius of curvature R gradually increases from the central position Rc in the main scanning direction to both sides, and the transition point
On the contrary, it is preferable to set Rh so that it gradually becomes smaller. Also, as shown in FIG. 1B, when the cutting shape is a cutting shape cut along the main scanning direction, its radius of curvature R is It is better to set it so that it gradually becomes smaller as it goes from the central position Rc 'in the main scanning direction to both sides Rt', but in the latter case, it cannot be molded using a plastic molding die,
Since it must be molded by thermal deformation, it is not suitable for mass production, whereas the former is moldable and can be used for mass production.
そしてこのようなレンズの断面構成を、前述したトーリ
ックレンズに適用する事により、該トーリックレンズ自
体にも像面湾曲矯正及び収差補正の機能を有する為、よ
り一層後記する効果を円滑に達成し得る。By applying the cross-sectional structure of such a lens to the toric lens described above, the toric lens itself also has the function of correcting the field curvature and the aberration correction, so that the effects described below can be achieved more smoothly. .
「実施例」 以下、本発明の好適な実施例を例示的に詳しく説明す
る。ただしこの実施例に記載されている構成部品の寸
法、材質、形状、その相対配置などは特に特定的な記載
がない限りは、この発明の範囲をそれのみに限定する趣
旨ではなく、単なる説明例に過ぎない。"Examples" Hereinafter, preferred examples of the present invention will be illustratively described in detail. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but merely illustrative examples. Nothing more than.
先ず面倒れ補正レンズ６に本発明を適用した光走査装置
の具体的構成を第２的に基づいて説明するに、偏向器３
には外接円の直径が40mmで、その偏向面3aが六面体であ
るポリゴンミラーを用い、その反射幅を適宜選択してｆ
θレンズに入射される画角が略80°になるように設定し
ている。First, a specific configuration of an optical scanning device in which the present invention is applied to the surface tilt correction lens 6 will be described based on a second way.
Is a polygonal mirror whose circumscribed circle has a diameter of 40 mm and whose deflecting surface 3a is a hexahedron.
The angle of view incident on the θ lens is set to about 80 °.
ｆθレンズ４は凹レンズと凸レンズの組み合わせからな
る２枚構成のレンズ系を用いている。The fθ lens 4 uses a two-lens system composed of a combination of a concave lens and a convex lens.
面倒れ補正レンズ６にはビーム入射側を主走査方向に沿
って僅かに凸（例えば曲率半径Ｒを約770mm）に湾曲さ
せ、その肉厚を約6mm,主走査方向の延設長さを約210mm
に設定したトーリックレンズ60を用い、副走査方向の切
断断面のビーム入射側の曲率半径Ｒを、第1A図に示すよ
うに、その曲率半径Ｒが主走査方向の中央位置Rcよりそ
の両側に進むに連れ徐々に大になり、そしてその途中に
変移点Rhで逆に徐々に小になるように設定している。例
えば中央位置Rcにおける曲率半径Ｒを15.9mm、該中央位
置Rcより略70mm隔てた変移点Rh位置における曲率半径Ｒ
を16.2mmに夫々設定している。The surface tilt correction lens 6 is curved so that the beam incident side is slightly convex along the main scanning direction (for example, the radius of curvature R is about 770 mm), the wall thickness is about 6 mm, and the extension length in the main scanning direction is about 210 mm
Using the toric lens 60 set to, the radius of curvature R on the beam incident side of the cross section in the sub-scanning direction advances from the central position Rc in the main scanning direction to both sides thereof, as shown in FIG. 1A. It is set so that it gradually becomes larger as it goes to, and then gradually becomes smaller at the transition point Rh on the way. For example, the radius of curvature R at the center position Rc is 15.9 mm, and the radius of curvature R at the transition point Rh position approximately 70 mm apart from the center position Rc.
Are set to 16.2 mm respectively.
そして偏向面3aから被記録媒体５母線までの距離を約22
0mm,及び該母線上での光軸上におけるビーム直径が約10
0μｍ程度になるよう設定している。The distance from the deflecting surface 3a to the recording medium 5 bus bar is set to about 22.
0 mm, and the beam diameter on the optical axis on the bus is about 10
It is set to be about 0 μm.
かかる実施例において曲率半径Ｒを同一に設定した前記
と同様なトーリックレンズ61を比較例として用い、被記
録媒体５母線上における副走査方向における像湾曲度合
を調べた所、本実施例においては第３図（Ｃ）に一点鎖
線で示すように、僅かに波形状になるもその誤差は最大
略５μｍ以内に収まり、被記録面とほぼ合致させる事が
出来る。In this embodiment, the same toric lens 61 having the same radius of curvature R as described above was used as a comparative example, and the degree of image curvature in the sub-scanning direction on the generatrix of the recording medium 5 was examined. As shown by the alternate long and short dash line in FIG. 3 (C), the error is contained within a maximum of about 5 μm even if it is slightly wavy, and it can be almost matched with the recording surface.
一方比較例においては第３図（Ｂ）下側グラフ図の一点
鎖線に示すように、大きな波形形状となり、約20〜30％
程度ビーム直径が変化する。On the other hand, in the comparative example, as shown by the alternate long and short dash line in the lower graph of FIG.
The beam diameter changes to some extent.
尚、本実施例においては、前記のようなトーリックレン
ズ60を面倒れ補正レンズ６に適用したが、ｆθレンズに
も適用する事が出来る。In this embodiment, the toric lens 60 as described above is applied to the surface tilt correction lens 6, but it can also be applied to the fθ lens.
即ち現状ではｆθレンズの収差誤差を極力少なくする為
に、複数のレンズの組み合わせから構成しているが、前
記トーリックレンズ60は副走査方向の収差誤差にも効果
を有する為に、これをｆθレンズとして適用する事によ
り、単一又は少枚数のレンズでｆθレンズが構成出来、
部品点数の削減と製造の容易化が図れる。That is, at present, a plurality of lenses are combined to minimize the aberration error of the fθ lens, but the toric lens 60 has an effect on the aberration error in the sub-scanning direction. As a result, the fθ lens can be constructed with a single lens or a small number of lenses.
The number of parts can be reduced and manufacturing can be facilitated.
「発明の効果」 以上記載した如く本発明によれば、本発明に係るレンズ
構成を面倒れ補正レンズとして適用した場合は、前記偏
向器の画角を拡げ、焦点距離を短かくしつつも前記像面
湾曲が発生する事がない光走査装置を提供出来、 又ｆθレンズとして適用した場合は単一又は少枚数のレ
ンズでｆθレンズを構成しつつも収差補正を行う事が出
来、これにより部品点数の削減と製造の容易化が達成さ
れる。[Advantages of the Invention] As described above, according to the present invention, when the lens configuration according to the present invention is applied as a surface tilt correction lens, the image angle of the deflector is widened and the focal length is shortened, but the image is reduced. It is possible to provide an optical scanning device in which no surface curvature occurs, and when it is applied as an fθ lens, it is possible to perform aberration correction while configuring the fθ lens with a single lens or a small number of lenses. Reduction and simplification of manufacturing are achieved.
第1A図及び第1B図は、本発明の実施例に係るトーリクレ
ンズの断面形状を示す説明図、第２図は本発明が適用さ
れる光走査装置を示す概略図、第３図（Ａ）（Ｂ）
（Ｃ）は夫々従来例と本発明の実施例におけるビーム径
の像面湾曲度合いを示すグラフである。1A and 1B are explanatory views showing a sectional shape of a Toric lens according to an embodiment of the present invention, FIG. 2 is a schematic view showing an optical scanning device to which the present invention is applied, and FIG. 3 (A). (B)
(C) is a graph showing the degree of field curvature of the beam diameter in the conventional example and the example of the present invention, respectively.
Claims (3)
録媒体間に介在させる各種集束レンズにおいて、 前記集束レンズを、ビーム入射側を主走査方向に沿って
凸に湾曲させたトーリックレンズで形成するとともに、
該集束レンズの副走査方向に沿って切断されたビーム入
射側の切断形状が、その曲率半径が主走査方向の中央位
置よりその両側に進むに連れ徐々に大になり、そしてそ
の途中に変移点で逆に徐々に小になるように設定した事
を特徴とする集束レンズ1. Various focusing lenses interposed between a deflector that scans a modulated beam and a recording medium, wherein the focusing lens is a toric lens in which a beam incident side is convexly curved along a main scanning direction. As it forms
The cutting shape on the beam incident side cut along the sub-scanning direction of the focusing lens gradually increases as its radius of curvature advances from the central position in the main scanning direction to both sides thereof, and a transition point in the middle thereof. On the contrary, the focusing lens is characterized by being set so that it gradually becomes smaller.
録媒体間に介在させる各種集束レンズにおいて、 前記集束レンズを、ビーム入射側を主走査方向に沿って
凸に湾曲させたトーリックレンズで形成するとともに、
該集束レンズの主走査方向に沿って切断されたビーム入
射側の切断形状の曲率半径が、主走査方向の中央位置と
その両側位置で夫々曲率半径を異ならせた事を特徴とす
る集束レンズ2. Various focusing lenses interposed between a deflector for scanning a modulated beam and a recording medium, wherein the focusing lens is a toric lens in which a beam incident side is convexly curved along a main scanning direction. As it forms
A focusing lens characterized in that the radius of curvature of the cutting shape on the beam incident side cut along the main scanning direction of the focusing lens is different between the central position in the main scanning direction and the side positions thereof.
走査方向の中央位置よりその両側に進むに連れ徐々に小
になるように設定した事を特徴とする集束レンズ3. The focusing lens according to claim 2, wherein the radius of curvature of the cut shape cut along the main scanning direction is set to be gradually smaller as it goes to both sides from the central position in the main scanning direction. Focusing lens characterized by
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61098323A JPH0734065B2 (en) | 1986-04-30 | 1986-04-30 | Focusing lens used in optical scanning device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61098323A JPH0734065B2 (en) | 1986-04-30 | 1986-04-30 | Focusing lens used in optical scanning device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62255915A JPS62255915A (en) | 1987-11-07 |
| JPH0734065B2 true JPH0734065B2 (en) | 1995-04-12 |
Family
ID=14216696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61098323A Expired - Lifetime JPH0734065B2 (en) | 1986-04-30 | 1986-04-30 | Focusing lens used in optical scanning device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0734065B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2618040B2 (en) * | 1988-07-15 | 1997-06-11 | 株式会社リコー | Optical scanning device |
| US8213068B1 (en) | 1994-09-06 | 2012-07-03 | Canon Kabushiki Kaisha | Scanning optical apparatus |
| KR100490433B1 (en) | 2003-06-10 | 2005-05-17 | 삼성전자주식회사 | Laser scanning unit and f-θ lens |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58179813A (en) * | 1982-03-21 | 1983-10-21 | Konishiroku Photo Ind Co Ltd | Optical beam scanner |
| JPS58179814A (en) * | 1982-03-21 | 1983-10-21 | Konishiroku Photo Ind Co Ltd | Optical beam scanner |
| JPS58200214A (en) * | 1982-05-19 | 1983-11-21 | Hitachi Ltd | Scanning optical system |
| JPS60133416A (en) * | 1983-12-22 | 1985-07-16 | Ricoh Co Ltd | Cylindrical lens for surface inclination correcting and scanning optical system |
| JPS61275814A (en) * | 1985-05-31 | 1986-12-05 | Toshiba Corp | Laser beam scanner |
-
1986
- 1986-04-30 JP JP61098323A patent/JPH0734065B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62255915A (en) | 1987-11-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |