JPS5930521A - Optical scanner - Google Patents
Optical scannerInfo
- Publication number
- JPS5930521A JPS5930521A JP14152082A JP14152082A JPS5930521A JP S5930521 A JPS5930521 A JP S5930521A JP 14152082 A JP14152082 A JP 14152082A JP 14152082 A JP14152082 A JP 14152082A JP S5930521 A JPS5930521 A JP S5930521A
- Authority
- JP
- Japan
- Prior art keywords
- plane
- cylindrical lens
- deflection
- point
- acousto
- 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.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/29—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the position or the direction of light beams, i.e. deflection
- G02F1/33—Acousto-optical deflection devices
Landscapes
- Physics & Mathematics (AREA)
- Nonlinear Science (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Mechanical Optical Scanning Systems (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は、平面内で光束を偏向する光偏向器を２個使用
し、それぞれの偏向面が直交するように組み合わせるこ
とによって、全体として二次元走査を行う光走査装置に
関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention provides an optical scanning device that performs two-dimensional scanning as a whole by using two optical deflectors that deflect a light beam within a plane and combining them so that their deflection planes are perpendicular to each other. It is related to.
第１図は音響光学素子と回転鏡を用いた光走査装置の従
来例を示し、レーザー光源部１から光束りが出射され、
この光束りの光路に沿って順次に、ＸＺ平面内で光束り
を偏向する音響光学素子２、音響光学素子２によるシリ
ンドリカルレンズ効果を補正するために用いられるｘＺ
平面内でのみ屈折力を有する円筒レンズ３、ＸＹ平面内
で光束りを偏向する回転鏡４、走査光学系５及び被走査
面６が配置されている。変調信号に基づいてレーザー光
源部１から発せられた平行光束りは、音響光学素子２に
よりｘＺ平面内で偏向され、更に回転鏡４によってＸＹ
平面内で偏向された後に走査光学系５によって被走査面
６」二に結像され、二次元走査を行うことになる。音響
光学素子２の掃引周波数を連続的に変化させて偏向を行
う場合には、入射光束りの径内に異なる周波数の超音波
が存在するために、それぞれの超音波成分によって回折
される光線の方向が異なり、その結果偏向された光束り
の形状に変化が生じる。即ち、音響光学素子２は入射光
束りを偏向すると同時に、入射光束りに対して偏向面内
でのみ屈折力を有する焦点距８１ Ｆのシリンドリカル
レンズの役割を有している。この焦点距離Ｆは偏向媒体
の音速をＶ、掃引時間をＴ、光の波長をλ、掃引周波数
帯域中をΔｆとすると、
Ｆ＝±Ｖ”Ｔ／（入・Δｆ） ・（１）で表さ
れる。ここで、正、負の符号は低周波から高周波に掃引
する場合は正、逆の場合は負となる。更に、音響光学素
子２の偏向点数Ｎは、入射光束の断面強度分布に依存す
る係数をａ、入射光束を横切るＭｉ音波の通過時間（ア
クセスタイム）をτとすると、
Ｎ＝（１／ａ）Δｆ＠τ ・・・（２）で表
されるが、シリンドリカルレンズ効果が存在するときの
偏向点数Ｎ′は、
Ｎ’ ＝１＋Ｎ （１−（τ／Ｔ）） ・・・
（３）で表され、偏向点数は低下する。FIG. 1 shows a conventional example of an optical scanning device using an acousto-optic element and a rotating mirror, in which a beam of light is emitted from a laser light source section 1,
Sequentially along the optical path of this light beam, an acousto-optic element 2 that deflects the light beam within the XZ plane, and an xZ element used to correct the cylindrical lens effect caused by the acousto-optic element 2.
A cylindrical lens 3 having refractive power only within a plane, a rotating mirror 4 that deflects a beam within an XY plane, a scanning optical system 5, and a surface to be scanned 6 are arranged. A parallel beam of light emitted from the laser light source 1 based on the modulation signal is deflected in the xZ plane by the acousto-optic element 2, and further deflected in the XY plane by the rotating mirror 4.
After being deflected within a plane, the scanning optical system 5 forms an image on the scanned surface 6'' to perform two-dimensional scanning. When deflection is performed by continuously changing the sweep frequency of the acousto-optic element 2, since ultrasonic waves of different frequencies exist within the diameter of the incident light beam, the light rays diffracted by each ultrasonic component differ. The directions are different, resulting in a change in the shape of the deflected beam. That is, the acousto-optic element 2 deflects the incident light beam and at the same time has the role of a cylindrical lens with a focal length of 81 F that has refractive power only within the deflection plane with respect to the incident light beam. This focal length F is expressed as F=±V"T/(in/Δf) (1), where V is the sound speed of the deflection medium, T is the sweep time, λ is the wavelength of light, and Δf is the middle of the sweep frequency band. Here, the positive and negative signs are positive when sweeping from low frequency to high frequency, and negative when sweeping from low frequency to high frequency.Furthermore, the number N of deflection points of the acousto-optic element 2 depends on the cross-sectional intensity distribution of the incident light beam. If the dependent coefficient is a, and the transit time (access time) of the Mi sound wave crossing the incident light beam is τ, then N=(1/a)Δf@τ...(2), but the cylindrical lens effect The number of deflection points N' when they exist is N' = 1 + N (1-(τ/T))...
It is expressed as (3), and the number of deflection points decreases.
従って、第１図に示す光走査袋：６．において、ｊ３響
光学素子２によるシリンドリカルレンズ効果を補正しな
いとすれば、被走査面６上においてＺ軸方向の解像点数
が低下し、更には走査光学系５の物点が非点隔差を持つ
ために結像スポットの形状も悪化する。このような現象
を防止するために、通常はｘＺ平面内でのみＦ’＝−Ｆ
の焦点距離を有する円筒レンズ３を音響光学素子２の射
出窓に近接して配置する必要がある。Therefore, the optical scanning bag shown in FIG. 1:6. In this case, if the cylindrical lens effect by the J3 acoustic optical element 2 is not corrected, the number of resolution points in the Z-axis direction on the scanned surface 6 will decrease, and furthermore, the object point of the scanning optical system 5 will have an astigmatism difference. Therefore, the shape of the imaged spot also deteriorates. To prevent this phenomenon, we usually set F'=-F only in the xZ plane.
It is necessary to arrange the cylindrical lens 3 having a focal length of 2 in the vicinity of the exit window of the acoustooptic element 2.
第１図の従来例は回転鏡４の反射面が傾くと、被走査面
６上に正確に結像されないという問題を有しており、こ
の問題を解決した従来例を第２図に示す。この第２図に
おいては、円筒レンズ３と回転鏡４との間にｘＺ平面内
にのみ屈折力を有する円筒レンズ７を挿入し、回転鏡４
の鏡面上に線像を形成するようになっている。第１図の
走査光学系５の代りにアナモフィック走査光学系８を配
置し、ＹＺ平面内においては回転鏡４の鏡面と被走査面
６とを光学的に共役な関係とじている。The conventional example shown in FIG. 1 has a problem in that when the reflecting surface of the rotating mirror 4 is tilted, an image cannot be accurately formed on the scanned surface 6. A conventional example that solves this problem is shown in FIG. In FIG. 2, a cylindrical lens 7 having refractive power only in the xZ plane is inserted between the cylindrical lens 3 and the rotating mirror 4, and the rotating mirror 4
A line image is formed on the mirror surface of the An anamorphic scanning optical system 8 is arranged in place of the scanning optical system 5 in FIG. 1, and the mirror surface of the rotating mirror 4 and the surface to be scanned 6 are optically conjugate in the YZ plane.
従って、回転鏡４の回動中にその回転軸がＺ軸から傾い
ても、光束りは被走査面６上の所望の位置に結像する極
めて有利な機能を持っている。しかしながら、この第２
図に示す光走査装置においては、次に述べるような欠点
がある。Therefore, even if the rotating axis of the rotating mirror 4 is tilted from the Z axis during rotation, the light beam has an extremely advantageous function of forming an image at a desired position on the scanned surface 6. However, this second
The optical scanning device shown in the figure has the following drawbacks.
即ち、第１に音響光学素子２と回転鏡４の間に少なくと
も２枚の円筒レンズ３．７を使用する必要があるが、一
般に円筒レンズは球面レンズに比べてその製作が困難で
あり、更に配置に際しては、光軸を回転軸とする回転偏
芯に対しても綿密な配慮が必要である。第２図に示す光
走査装置において、円筒レンズ３．７の光軸の廻りの微
小な回転偏芯が存在すると、被走査面６上の結像スポッ
トの形状は著しく劣化する。従って、円筒レンズ３．７
の製作、組立に際しては高度に熟練された技術を必要と
するのである。That is, firstly, it is necessary to use at least two cylindrical lenses 3.7 between the acousto-optic element 2 and the rotating mirror 4, but cylindrical lenses are generally more difficult to manufacture than spherical lenses, and When arranging them, careful consideration must also be given to rotational eccentricity with the optical axis as the rotation axis. In the optical scanning device shown in FIG. 2, if there is a minute rotational eccentricity around the optical axis of the cylindrical lens 3.7, the shape of the imaged spot on the surface to be scanned 6 will be significantly deteriorated. Therefore, the cylindrical lens 3.7
Manufacturing and assembly require highly skilled techniques.
また第２の欠点としては、音響光学素子２の掃引状態が
変る場合、換言すれば（１）式に示すパラメータの値を
変えて使用するときには、それに応じた焦点距ＭＦ’を
有する円筒レンズ３を準備する必要があることである。A second drawback is that when the sweep state of the acousto-optic element 2 changes, in other words, when the value of the parameter shown in equation (1) is changed, the cylindrical lens 3 having a focal length MF' corresponding to the change in the sweep state of the acousto-optic element 2 is used. It is necessary to prepare.
円筒レンズ３をシリンドリカルズームレンズで構成する
手段も考えられるが、甚だ複雑かつ高価な光学系となり
好ましくない。Although it is conceivable to configure the cylindrical lens 3 with a cylindrical zoom lens, this would result in an extremely complicated and expensive optical system, which is not preferable.
本発明の目的は、上述した従来例の欠点を解７１′ｌし
、より簡単な構成で良好な性能の光走査装置を提供する
ことにあり、その要旨は、光源部力）ら１１３射される
光束の進行に従って音響光学素子の＼ら成る第１の偏向
器、該第１の偏向器により偏向された光束が形成する第
１の偏向面とほぼ直交する第２の偏向面内で偏向を行う
第２の偏向器、アナモフィック特性を有する走査光学系
、被走査面のｌ１ｌｌ’ｉに配置された光走査装置にお
いて、前記第１の偏向器は第１の偏向面内で音響光学素
子の掃・中周波数を連続的に変化させて偏向を行うこと
に起因するシリンドリカルレンズ効果によって生ずる光
束の結像を、直接又は第１の偏向面内にのみ正の屈折力
を有するシリンドリカルレンズにより１１ｆＪ記第２の
偏向器の偏向点に形成するようにしたことを特徴とする
ものである。An object of the present invention is to solve the above-mentioned drawbacks of the conventional example and to provide an optical scanning device with a simpler structure and better performance. A first deflector consisting of an acousto-optic element, and a second deflection plane substantially orthogonal to the first deflection plane formed by the light flux deflected by the first deflector, deflect the light flux according to the progress of the light flux. In the optical scanning device, the first deflector scans the acousto-optic element within the first deflection plane.・The imaging of the light beam caused by the cylindrical lens effect caused by deflection by continuously changing the medium frequency is performed directly or by a cylindrical lens having positive refractive power only in the first deflection plane. This is characterized in that it is formed at the deflection point of the second deflector.
本発明を第３図以下に図示の実施例に基づ１７）て詳細
に説明する。The present invention will be explained in detail based on the embodiment shown in FIG. 3 (17).
第３図は音響光学素子２による第１の偏向面内での構成
を示す展開図であり、レーザー光源部１からの平行光束
りは音響光学素子２のシリンドリカルレンズ効果により
発散光として偏向され、音響光学素子２は負のシリンド
リカルレンズ効果を有し、Ｐ点に虚像を形成している。FIG. 3 is a developed view showing the configuration within the first deflection plane by the acousto-optic element 2, in which the parallel light beam from the laser light source section 1 is deflected as diverging light by the cylindrical lens effect of the acousto-optic element 2, The acousto-optic element 2 has a negative cylindrical lens effect and forms a virtual image at point P.
ここで、音響光学素子２と回転鏡４との間に第１の偏向
面内でのみ屈折力を有する円筒レンズ１０が挿入され、
Ｐ点と回転鏡４の鏡面上のＰ′点とを光学的に共役な配
置とするようになっている。更に、アナモフィックな走
査光学系１１を回転鏡４と被走査面６との間に配置し、
Ｐ点と被走査面一層上のＰ′点とを光学的に共役な関係
としている。一方、第４図は回転鏡４による第２の偏向
面内での構成を展開図で示しており、レーザー光源部ｌ
からの平行光束りは図示の平面内では平行光束のまま進
行し１回転鏡４により偏向され走査光学系１１により被
走査面６上に結像される。Here, a cylindrical lens 10 having refractive power only within the first deflection plane is inserted between the acousto-optic element 2 and the rotating mirror 4,
Point P and point P' on the mirror surface of rotating mirror 4 are arranged to be optically conjugate. Furthermore, an anamorphic scanning optical system 11 is arranged between the rotating mirror 4 and the surface to be scanned 6,
Point P and point P', which is one layer above the surface to be scanned, are in an optically conjugate relationship. On the other hand, FIG. 4 shows the configuration in the second deflection plane by the rotating mirror 4 in a developed view, and shows the laser light source section l.
The parallel light beam from the mirror travels as a parallel light beam within the illustrated plane, is deflected by the one-rotation mirror 4, and is imaged by the scanning optical system 11 on the surface to be scanned 6.
このような配置をすることによって、簡略化された構成
で音響光学素子２の偏向点数の低下を生ずることなく良
好な結像性能を得るに至る。この場合、音響光学素子２
の掃引状ｙ匙が変化しても、円筒レンズｌＯを光軸方向
に平行移動させて、新たなるＰ点と鏡面りのＰ′点とを
光学的に共役な関係とすることができる。更に、レーザ
ー光源部１からの光束りが弁子行光であっても、走査光
学系１１はアナモフィック光学系であるので、Ｌ述した
原理を適用することが可能である。By adopting such an arrangement, good imaging performance can be obtained with a simplified configuration without causing a decrease in the number of deflection points of the acousto-optic element 2. In this case, the acousto-optic element 2
Even if the swept y-spoon changes, the cylindrical lens lO can be moved in parallel in the optical axis direction, and the new point P and the mirror-surfaced point P' can be brought into an optically conjugate relationship. Furthermore, even if the light beam from the laser light source section 1 is a beam of light, since the scanning optical system 11 is an anamorphic optical system, the principle described above can be applied.
第３図、第４図においては、音響光学素子２か負のシリ
ンドリカルレンズ効果を有する例を挙げて説明したが、
正のシリンドリカルレンズ効果を有する場合でも、音響
光学素子２によるＰ点と回転鏡４の鏡面上のＰ′点とを
光学的に共役な関係とするように、円筒レンズ１０を配
置すればよい。In FIGS. 3 and 4, an example in which the acousto-optic element 2 has a negative cylindrical lens effect has been described.
Even in the case of having a positive cylindrical lens effect, the cylindrical lens 10 may be arranged so that the point P formed by the acousto-optic element 2 and the point P' on the mirror surface of the rotating mirror 4 are in an optically conjugate relationship.
第５図、第６図は他の実施例であり、第５図は音響光学
素子２による第１の偏向面内での構成の展開図、第６図
は回転鏡４による第２の偏向面内での展開図を示してい
る。第５図に示す平面内において、音響光学素子２が正
の屈折力のシリンドリカルレンズ効果を有するように使
用して、レーザー光源部１のＰ点が回転鏡４の鏡面上に
直接形成するようにされている。この実施例によれば音
響光学素子２と回転鏡４との間に円筒レンズ１０を用い
ることなく、簡略化された装置構成で良好な結像性能を
得ることが可能となる。5 and 6 show other embodiments, FIG. 5 is a developed view of the configuration within the first deflection plane by the acousto-optic element 2, and FIG. 6 is a development view of the configuration within the first deflection plane by the rotating mirror 4. It shows the development diagram inside. In the plane shown in FIG. 5, the acousto-optic element 2 is used so as to have a cylindrical lens effect with positive refractive power, so that the point P of the laser light source section 1 is formed directly on the mirror surface of the rotating mirror 4. has been done. According to this embodiment, it is possible to obtain good imaging performance with a simplified device configuration without using the cylindrical lens 10 between the acousto-optic element 2 and the rotating mirror 4.
以上説明したように本発明に係る光走査装置は、組立て
時における調整が極めて困難であるという欠点を解消し
、光走査装置のシリンドリカルレンズ効果によって生ず
る光束の集光位置を回転鏡の偏向点にするという簡単な
構成として、組立て時の困難性を解決できる利点がある
。As explained above, the optical scanning device according to the present invention solves the drawback that adjustment during assembly is extremely difficult, and allows the focusing position of the light beam generated by the cylindrical lens effect of the optical scanning device to be set at the deflection point of the rotating mirror. This simple structure has the advantage of solving difficulties during assembly.
第１図、第２図は従来例の構成図、第３図以下は本発明
に係る光走査装置の実施例を示し、第３図と第４図はそ
れぞれ第１の実施例の音響光学素子による第１の偏向面
内、回転鏡による第２の偏向面内の光路の展開図、第５
図、第６図はそれぞれ第２の実施例の音響光学素子によ
る第１の偏向面内、回転鏡による第２の偏向面内の光路
の展開図である。
符号１はレーザー光源部、２は音響光学素子、４は回転
鏡、６は被走査面、ｌＯは円筒レンズ。
１１はアナモフィック走査光学系である。
特許出願人 キャノン株式会社1 and 2 are block diagrams of a conventional example, FIG. 3 and the following show embodiments of the optical scanning device according to the present invention, and FIGS. 3 and 4 respectively show an acousto-optic element of the first embodiment. A developed view of the optical path in the first deflection plane by the rotating mirror and in the second deflection plane by the rotating mirror, 5th
6 are developed views of the optical path in the first deflection plane by the acousto-optic element of the second embodiment and in the second deflection plane by the rotating mirror, respectively. 1 is a laser light source, 2 is an acousto-optic element, 4 is a rotating mirror, 6 is a surface to be scanned, and lO is a cylindrical lens. 11 is an anamorphic scanning optical system. Patent applicant Canon Co., Ltd.
Claims (1)
学素子から成る第１の偏向器、該第１の偏向器により偏
向された光束が形成する第１の偏向面とほぼ直交する第
２の偏向面内で偏向を行う第２の偏向器、アナモフィッ
ク特性を有する走査光学系、被走査面の順に配置された
光走査装置番こおいて、前記第１の偏向器は第１の偏向
面内で音響光学素子の掃引周波数を連続的に変化させて
偏向を行うことに起因するシリンドリカルレンズ効果に
よって生ずる光束の結像を、直接又は第１の偏向面内に
のみ正の屈折力を有するシリンドリカルレンズにより前
記第２の偏向器の偏向点に形成するようにしたことを特
徴とする光走査装置。1. A first deflector made of an acousto-optic element that follows the progress of the light beam emitted from the light source, and a second deflection plane that is substantially orthogonal to the first deflection plane formed by the light beam deflected by the first deflector. A second deflector that performs deflection within a plane, a scanning optical system having anamorphic characteristics, and an optical scanning device are arranged in this order, and the first deflector deflects within the first deflection plane. Imaging of the light flux generated by the cylindrical lens effect caused by deflection by continuously changing the sweep frequency of the acousto-optic element is performed directly or by a cylindrical lens having positive refractive power only in the first deflection plane. An optical scanning device characterized in that the optical scanning device is formed at a deflection point of the second deflector.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14152082A JPS5930521A (en) | 1982-08-14 | 1982-08-14 | Optical scanner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP14152082A JPS5930521A (en) | 1982-08-14 | 1982-08-14 | Optical scanner |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5930521A true JPS5930521A (en) | 1984-02-18 |
Family
ID=15293874
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP14152082A Pending JPS5930521A (en) | 1982-08-14 | 1982-08-14 | Optical scanner |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5930521A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5729425A (en) * | 1995-05-22 | 1998-03-17 | Tdk Corporation | High voltage capacitor and magnetron having porcelain dielectric material |
| US6665112B2 (en) | 2000-11-30 | 2003-12-16 | Nec Corporation | Optical reticle substrate inspection apparatus and beam scanning method of the same |
| CN107005019A (en) * | 2014-09-18 | 2017-08-01 | 费哈激光技术有限责任公司 | Tune Q CO with acousto-optic modulator2Laser materials processing system |
-
1982
- 1982-08-14 JP JP14152082A patent/JPS5930521A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5729425A (en) * | 1995-05-22 | 1998-03-17 | Tdk Corporation | High voltage capacitor and magnetron having porcelain dielectric material |
| US6665112B2 (en) | 2000-11-30 | 2003-12-16 | Nec Corporation | Optical reticle substrate inspection apparatus and beam scanning method of the same |
| CN107005019A (en) * | 2014-09-18 | 2017-08-01 | 费哈激光技术有限责任公司 | Tune Q CO with acousto-optic modulator2Laser materials processing system |
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