JP2004302055A - Beam emitting angle correction optical unit and laser marking device furnished with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angle correction correction optical unit in which the emission angle of a beam is simply and accurately corrected and to provide an inexpensive laser marking device which is furnished with the optical unit and emits a plurality of lines of light. <P>SOLUTION: The device has a first wedge prism which is composed of such a light transmissible body as glass or plastic, a means which holds the first wedge prism turnably around a predetermined axis, a second wedge prism composed of a light transmissive body arranged closely or in contact with the first wedge prism and a means holds the second wedge prism turnably around the predetermined axis independently of the first wedge prism, and the device is so composed that a beam made incident to the first wedge prism is emitted from the second wedge prism and the angle of the emitted beam is corrected by independently turning the first and the second wedge prisms by a desired angle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

が得られる。すなわち、
ふれ角δ＝（プリズムの屈折率−１）×（プリズム頂角） （６）
で表される。
【００１９】
次に図３に示すように垂直面を有するプリズム２の垂直面がｘｙ平面と平行になるようにプリズムが置かれた場合を考える。このプリズム２は回転軸ＡＡ´を中心として任意の角度φだけ回転できるものとする。ここで回転軸ＡＡ´はｚ軸と平行である。なお、初期状態ではプリズム２の回転角φは０°とする。
【００２０】
今、プリズム斜面における法線のｘｚ平面及びｙｚ平面への正射影を考える。
【００２１】
プリズム回転角をφ、プリズムの頂角をαとすると、
ｙｚ平面への法線の正射影の式は
ｙ＝ｔａｎα・ｃｏｓφ・ｚ
となるため、頂角の正射影は
ｔａｎ^{− １}（ｔａｎα・ｃｏｓφ）≒α・ｃｏｓφ となる。
したがって（６）式からｙｚ面におけるふれ角δ_φｙｚは、
δ_φｙｚ＝（ｎ−１）α・ｃｏｓφ （７）が得られる。
【００２２】
同様にｘｚ平面への法線の正射影の式は
ｘ＝ｔａｎα・ｓｉｎφ・ｚ
であるため、頂角の正射影は
ｔａｎ^{− １}（ｔａｎα・ｓｉｎφ）≒α・ｓｉｎφ となる。
したがって（６）式からｘｚ面におけるふれ角δ_φｘｚは
δ_φｘｚ＝（ｎ−１）α・ｓｉｎφ （８） が得られる。
【００２３】
また、図４に示すように頂角α_１とα_２の２種類のプリズム２Ａ及び２Ｂを組合せたプリズムに入射角Ｉ_１でビームＢ１が入射し出射ビームＢ３が基準軸（ここではｘ軸）となす角度をβとすると図から明らかなように β＝δ−Ｉ_１＋α_１ となる。入射ビームＢ１が基準軸となす角度をγとするとγ＝Ｉ_１−α_１であるから
β＝δ−（γ＋α_１）＋α_１
＝δ−γ
が成立する。 すなわち
β＝（組合せプリズムふれ角）−（基準軸と入射ビームがなす角度）（９）
で表される。
【００２４】
一方、頂角α_１のプリズム２Ａで得られるふれ角をδ_１ 頂角α_２のプリズム２Ｂで得られるふれ角をδ_２とすると、組合せプリズムにより得られるふれ角δは
δ＝δ_１＋δ_２ （１０） で与えられる。
【００２５】
今、頂角が共にαである２個のプリズムを組合せた場合について考える。
入射ビーム側のプリズムをφ_１、出射ビーム側のプリズムをφ_２だけ回転させた場合のふれ角のｙｚ平面成分は（７）式から
δ_{φ １ ｙｚ}＝（ｎ−１）α・ｃｏｓφ_１ （１１）
δ_{φ ２ ｙｚ}＝（ｎ−１）α・ｃｏｓφ_２ （１２）
となるので（１０）式から組合せプリズムのふれ角δ_φｙｚは
δ_φｙｚ＝（ｎ−１）α・ｃｏｓφ_１＋（ｎ−１）α・ｃｏｓφ_２ （１３） となる。
同様にｘｚ平面成分は（８）式から
δ_{φ １ ｘｚ}＝（ｎ−１）α・ｓｉｎφ_１ （１４）
δ_{φ ２ｘ ｚ}＝（ｎ−１）α・ｓｉｎφ_２ （１５）
となるので（１０）式から組合せプリズムのふれ角δ_φｘｚは
δ_φｘｚ＝（ｎ−１）α・ｓｉｎφ_１＋（ｎ−１）α・ｓｉｎφ_２ （１６） となる。
したがって出射ビームが基準軸（ここではｚ軸）となす角度βのｙｚ平面成分は（１３）式と（９）式より

となる。
同様に出射ビームが基準軸（ここではｚ軸）となす角度βのｘｚ平面成分は（１６）式と（９）式より
β_ｘｚ＝（ｎ−１）α・ｓｉｎφ_１＋（ｎ−１）α・ｓｉｎφ_２−γ_{１ ｘｚ}
＝（ｎ−１）α・（ｓｉｎφ_１＋ｓｉｎφ_２）−γ_{１ ｘｚ} （１８） となる。
基準軸に対して入射ビームがある角度をなす場合に出射ビームと基準軸がなす角度を０°となるように角度補正を行うためには（１７）式及び（１８）式において β_ｙｚ＝０ β_ｘｚ＝０とすればよい。
すなわち
ｃｏｓφ_１＋ｃｏｓφ_２＝γ_{１ ｙｚ}／（ｎ−１）α （１９）
ｓｉｎφ_１＋ｓｉｎφ_２＝γ_{１ ｘｚ}／（ｎ−１）α （２０）
が同時に成り立つ場合である。この時、φは０°〜３６０°まで取り得るため、
−２≦ｃｏｓφ_１＋ｃｏｓφ_２≦２ であるから、
−２≦ γ_{１ ｙｚ}／（ｎ−１）α ≦２ となる。すなわち
−２（ｎ−１）α≦γ_{１ ｙｚ}≦２（ｎ−１）α （２１）となる。同様に
−２（ｎ−１）α≦γ_{１ ｘｚ}≦２（ｎ−１）α （２２）となる。
一般的にガラスあるいはプラスチック材の屈折率は１．４５≦ｎ≦１．９０の範囲に存在しているが、実用的には１．５前後の材料を用いることが多い。そこで（２１）式及び（２２）式においてｎ＝１．５を代入すると
−α≦γ_{１ ｙｚ}≦α （２３）
及び −α≦γ_{１ ｘｚ}≦α （２４） となる。
すなわちγ_{１ ｙｚ}及びγ_{１ ｘｚ}はプリズム頂角αより小さければ、完全に０°に補正可能となることが分かる。その時のプリズムの回転角度は（１９）式及び（２０）式から求めることができる。
本実施例ではプリズム材質として一般的な光学ガラスであるＢＫ７（屈折率ｎ＝１．５）を用い、頂角αの大きさが１°であるプリズムを２個用いて出射ビームの角度補正を行った場合について具体的に説明する。
【００２６】
今、入射ビームが基準軸となす角度γをそれぞれγ_{１ ｙｚ}＝０．０５° γ_{１ ｘｚ}＝０．５°とし、これらの数値を（１９）式及び（２０）式に入れて計算すると
ｃｏｓφ_１＋ｃｏｓφ_２＝０．０５／（１．５−１）・１
ｓｉｎφ_１＋ｓｉｎφ_２＝０．５／（１．５−１）・１
φ_１＝２４．４６° φ_２＝１４４．１２° が得られる。
すなわち、入射ビームが基準軸となす角度がγ_{１ ｙｚ}＝０．０５° γ_{１ ｘｚ}＝０．５°である時、入射側プリズムを２４．４６°出射側プリズムを１４４．１２°回転させた位置に配置することにより出射ビームと基準軸がなす角度を０°に補正することが可能となる。
（実施形態２）
図７は本発明にかかる光学ユニットの第２の実施形態を示す。この光学ユニット１は図１と同様に第１のウェッジプリズム２Ａと第２のウェッジプリズム２Ｂとが近接又は密着して配置されているが、第１のウェッジプリズム２Ａを保持するホルダ３Ａは固定配置され、第２のウェッジプリズム２Ｂを保持するホルダ３Ｂのみが軸Ａ−Ａ’を中心にして図の矢印の向きに回動できるように保持されている。
出射側のウェッジプリズム２Ｂのみを回転させて出射ビーム角度を補正する本実施形態の場合は、（１７）式及び（１８）式においてφ_１＝０°とした場合に相当する。
すなわち、
β_ｙｚ＝（ｎ−１）α・（１＋ｃｏｓφ_２）−γ_{１ ｙｚ} （２５）
β_ｘｚ＝（ｎ−１）α・ｓｉｎφ_２−γ_{１ ｘｚ} （２６） となる。
ここでβ_ｙｚ及びβ_ｘｚが０°となる時、上式においてβ_ｙｚ＝０ β_ｘｚ＝０とすると １＋ｃｏｓφ_２＝γ_{１ ｙｚ}／（ｎ−１）α
ｓｉｎφ_２＝γ_{１ ｘｚ}／（ｎ−１）α
φ_２は０°〜３６０°まで取り得るため、
０≦γ_{１ ｙｚ}／（ｎ−１）α≦２
−１≦γ_{１ ｘｚ}／（ｎ−１）α≦１
すなわち
０≦γ_{１ ｙｚ}≦２（ｎ−１）α （２７）
−（ｎ−１）α≦γ_{１ ｘｚ}≦（ｎ−１）α （２８） となる。
（２７）式及び（２８）式においてｎ＝１．５を代入すると
０≦γ_{１ ｙｚ}≦α （２９）
−０．５α≦γ_{１ ｘｚ}≦０．５α （３０） となる。
すなわち２個のプリズム２Ａ及び２Ｂのうち出射側プリズム２Ｂのみを回転させて出射ビーム角度を補正した場合、出射ビームＢ３のうちｙｚ平面成分あるいはｘｚ平面成分のいずれかを０°に補正することが可能である。この時、入射ビームＢ１が基準軸となす角度γとプリズム頂角の間には（２９）式及び（３０）式の関係を満たすことが必要となる。
【００２７】
本実施例ではプリズム材質としてＢＫ７（屈折率ｎ＝１．５）を用い、頂角αの大きさが１°であるプリズムを２個（２Ａ及び２Ｂ）用いて、出射側プリズム２Ｂのみ回転させて出射ビーム（ｙｚ平面成分）の角度補正を行った場合について具体的に説明する。今、入射ビームＢ１が基準軸となす角度γをγ_{１ ｙｚ}＝０．０５°とし、これらの数値を（２５）式に入れて計算すると
０＝（１．５−１）・１・（１＋ｃｏｓφ_２）−０．０５
ｃｏｓφ_２＝１５４．１６° が得られる。
すなわち、入射ビームＢ１が基準軸となす角度がγ_{１ ｙｚ}＝０．０５°である時、出射側プリズム２Ｂを１５４．１６°回転させた位置に配置することによりβ_ｙｚを０°に補正することが可能となる。
（実施形態３）
図８は本発明にかかる光学ユニットの第３の実施形態を示すもので１個のウェッジプリズム２がホルダ３Ａ及び３Ｂにより保持され、このプリズム２がＡ−Ａ’軸を中心に回動できるように構成されている。
１個のプリズム２を用いて出射ビーム角度を補正する場合は（１７）式において（ｎ−１）α・ｃｏｓφ_１＝０
及び（１８）式において（ｎ−１）α・ｓｉｎφ_１＝０ とした場合に相当する。
すなわち、
β_ｙｚ＝（ｎ−１）α・ｃｏｓφ_２−γ_{１ ｙｚ} （３１）
β_ｘｚ＝（ｎ−１）α・ｓｉｎφ_２−γ_{１ ｘｚ} （３２） となる。
ここでβ_ｙｚ及びβ_ｘｚが０°となる時、β_ｙｚ＝０ β_ｘｚ＝０とすると
ｃｏｓφ_２＝γ_{１ ｙｚ}／（ｎ−１）α
ｓｉｎφ_２＝γ_{１ ｘｚ}／（ｎ−１）α
φ_２は０°〜３６０°まで取り得るため、
−１≦γ_{１ ｙｚ}／（ｎ−１）α≦１
−１≦γ_{１ ｘｚ}／（ｎ−１）α≦１
すなわち
−（ｎ−１）α≦γ_{１ ｙｚ}≦（ｎ−１）α （３３）
−（ｎ−１）α≦γ_{１ ｘｚ}≦（ｎ−１）α （３４） となる。
（３３）式及び（３４）式においてｎ＝１．５を代入すると
−０．５α≦γ_{１ ｙｚ}≦０．５α （３５）
−０．５α≦γ_{１ ｘｚ}≦０．５α （３６） となる。
すなわち１個のプリズムのみ用いて出射ビーム角度を補正する場合、出射ビームＢ３のうちｙｚ平面成分あるいはｘｚ平面成分のいずれかを０°に補正することが可能である。この時、入射ビームＢ１が基準軸となす角度γとプリズム頂角の間には（３５）式及び（３６）式の関係を満たすことが必要となる。
【００２８】
本実施例ではプリズム材質としてＢＫ７（屈折率ｎ＝１．５）を用い、頂角αの大きさが１°であるプリズムを１個用いて、プリズムを回転させて出射ビーム（ｙｚ平面成分）の角度補正を行った場合について具体的に説明する。今、入射ビームが基準軸となす角度γをγ_{１ ｙｚ}＝０．０５°とし、これらの数値を（３１）式に入れて計算すると
０＝（１．５−１）・１・ｃｏｓφ_２−０．０５
ｃｏｓφ_２＝８４．２６°が得られる。
すなわち、入射ビームが基準軸となす角度がγ_{１ ｙｚ}＝０．０５°である時、プリズムを８４．２６°回転させた位置に配置することによりβ_ｙｚを０°に補正することが可能となる。
（実施形態４）
本発明にかかるビーム出射角度補正光学ユニットをレーザ墨出し装置に実装した形態について説明する。図５に示すようにレーザ墨出し装置１０は基本的にはライン光を発生させる光学系１４と光学系を水平に保つための支持機構部１５から構成されている。図６にライン光発生光学系１４の一例の概略を示す。
【００２９】
レーザ墨出し装置本体に対して水平方向に配置した半導体レーザ１６から出射されたレーザビームはコリメータレンズ１７によりビーム断面形状が円形であるコリメート光（平行光）Ｂ１に変換される。本実施形態ではコリメート光Ｂ１のビーム径は２ｍｍになるように設定している。また、この光学系１４にはビームスプリッター４が用いられており、入射光Ｂ１を３本の均一な強度の光に分岐している。すなわちこのビームスプリッター４はこの実施例ではガラス又はプラスチック等の光を透過する３個の部材を貼り合わせて構成され直方体形状をしている。第１の部材と第２の部材の貼り合わせ面には第１の光分離面４１が形成されている。すなわちこの光分離面４１で入射光が透過光と反射光に分離される。
【００３０】
さらに第２の部材と第３の部材の貼り合わせ面には第２の光分離面４２が形成されている。上記の反射光はビームスプリッター４の内部を進み、第２の光分離面４２で更に反射光と透過光に分離されるので３本の分岐光を得ることができる。したがって各光線の光路上にロッドレンズ５１、５２、５３を配置することで３本のライン光を得ることができる。
ここでビームスプリッター４は必ず加工誤差を持っているため、分岐光の出射角度には若干の誤差が含まれる。しかしレーザ墨出し装置の場合、ライン光の指示精度が厳しく規定されており、例えばライン光を照射し１０ｍ先で１ｍｍ以内の指示精度に押さえる必要がある。１０ｍで１ｍｍの精度に押さえるには、ビームスプリッター４の出射光が、理想的な水平線（ｘ軸）となす角度を０．００５°以内としなければならない。つまり各分岐光が理想ラインとなす角度が０．００５°を超える場合、補正が必要となる。この実施例ではビームスプリッター４から出射した光線の各光路にビーム出射角度補正光学ユニット１ａ、１ｂ、１ｃが配置されている。角度補正光学ユニット１ａ、１ｂ、１ｃの後にロッドレンズ５１、５２、５３を配置することにより発生するライン光の角度誤差を０とすることが可能となり、理想ラインと一致させることができる。
今、ビームスプリッター４から出射した光線の１つについて例を示す。ビーム出射角補正光学ユニット１ａに入射するビームが基準軸とそれぞれ
γ_{１ ｙｚ}＝０．０５° γ_{１ ｘｚ}＝０．５°の角度誤差を有している場合、これらの数値を（１９）式及び（２０）式に入れて計算すると
ｃｏｓφ_１＋ｃｏｓφ_２＝０．０５／（１．５−１）・１
ｓｉｎφ_１＋ｓｉｎφ_２＝０．５／（１．５−１）・１
φ_１＝２４．４６° φ_２＝１４４．１２° が得られる。
すなわち、ビーム出射角補正光学ユニット１ａの入射側プリズムを２４．４６°出射側プリズムを１４４．１２°回転させた位置に配置することにより出射ビームと基準軸がなす角度を０°に補正することが可能となる。同様にして残りの分岐光についてもビーム出射角補正光学ユニット１ｂ及び１ｃを用いて角度補正を行うことができる。その結果、それぞれのロッドレンズ５１、５２、５３を通して発生するライン光の角度誤差を０とすることが可能となり、理想ラインと一致させることができる。
【００３１】
【発明の効果】
上述のように本発明によるビーム出射角度補正光学ユニットを用いれば、簡易な方法で，ビーム出射角度を補正することが可能となる。また、本発明によるビーム出射角度補正光学ユニットをレーザ墨出し装置の光学系に搭載することで非常に高い指示精度のライン光を容易に得ることができるため、低コストで複数本の高精度墨出し用レーザライン光を発生させることが可能となった。その結果、従来は非常に高価であった複数ライン光照射用レーザ墨出し装置を低価格で得ることが可能となった。
【図面の簡単な説明】
【図１】本発明にかかるビーム出射角度補正光学ユニットの第１の実施例を示す概略図。
【図２】本発明のビーム出射角度補正光学ユニットによる角度補正原理を示す図。
【図３】本発明のビーム出射角度補正光学ユニットのプリズム配置例を示す概略図。
【図４】組合せプリズムによるビーム偏角作用を示す図
【図５】本発明のビーム出射角度補正光学ユニット搭載のレーザ墨出し装置の概略図。
【図６】本発明のレーザ墨出し装置におけるライン光発生光学系の概略図。
【図７】本発明にかかるビーム出射角度補正光学ユニットの第２の実施例を示す概略図。
【図８】本発明にかかるビーム出射角度補正光学ユニットの第３の実施例を示す概略図。
【符号の説明】
１、１ａ、１ｂ、１ｃ：ビーム出射角度補正光学ユニット
２Ａ、２Ｂ、２：ウェッジプリズム
３Ａ、３Ｂ：プリズムホルダ
４：ビームスプリッター
１０：レーザ墨出し装置
１４：ライン光発生光学系
１５：支持系
１６：半導体レーザ
１７：コリメートレンズ
４１、４２：光分離面
５１、５２、５３：ロッドレンズ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a beam emission angle correcting optical unit and a laser marking device equipped with the same.
[0002]
[Prior art]
[Patent Document 1] Japanese Patent Application Laid-Open No. 9-159451 (FIGS. 1 and 3)
When building a house, especially at the start of construction, it is essential to perform a task of setting a reference position for mounting various members and setting a level line for the positioning of member processing, that is, a blackout operation. Therefore, at the construction site, leveling was performed using instruments such as a level surveyor, multiple marks (black) were attached to the walls of the target structure, and they were connected to form a blacking line, which was used as a construction standard. .
[0003]
However, this operation must be performed by at least two people, which is very time-consuming and inefficient. In order to solve this problem, recently, the ink marking operation has been often performed efficiently using a laser marking device having a line light irradiation function. Since a laser marking device can easily perform a marking operation by one person, the laser marking device is becoming an indispensable building work tool for building work.
[0004]
The so-called "Tachi-Line" which draws a vertical line from the floor to the wall and the ceiling and two "Tachi-Lines" are simultaneously illuminated to draw a right angle line on the ceiling. There are various lines, such as a "Roku line" that draws a horizontal line on a wall, and a "ground ink" that irradiates a focused laser beam on the floor directly below a laser marking device.
[0005]
In order to improve the efficiency of the blackout operation using a laser blackout device, it is desired that a single laser blackout device can irradiate a plurality of blackout lines. Therefore, recently, a device capable of irradiating two or more lines with one device has been proposed.
[0006]
In order to irradiate a plurality of lines from one laser marking device, a method of mounting a plurality of laser light sources or a method of obtaining a plurality of lines by dividing laser light emitted from one laser light source is used. Conceivable.
[0007]
The closer the line light emitted from the laser marking device is to the ideal horizontal line and the ideal vertical line, the better the line pointing accuracy. Therefore, in a conventional laser marking device using a plurality of laser light sources, it is necessary to perform optical adjustment on an optical system attached to each laser light source in order to obtain line pointing accuracy. However, there is a problem that this assembling adjustment takes a considerable amount of time and increases the cost of the apparatus.
On the other hand, as a method of obtaining a plurality of line lights by dividing one laser light, for example, as disclosed in Japanese Patent Application Laid-Open No. 9-159451, a structure in which a plurality of half mirrors are stacked in series in a laser emission direction is disclosed. Are known. However, in the case of this method, it is necessary to finely adjust the installation angle of the half mirror in order to adjust the angle of the emitted light, so that the mechanism is complicated and the number of parts increases. Incidentally, in the method disclosed in Japanese Patent Application Laid-Open No. 9-159451, it is difficult to increase the pointing accuracy of the emitted light because no angle adjustment mechanism for the half mirror is provided.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a simple beam emission angle correction unit that solves such a conventional problem and a laser marking device equipped with the same.
Specifically, the present invention can easily correct the emission angle of the laser beam, and when the laser beam is divided into a plurality of beams by a half mirror, by arranging the laser beam in each optical path of the divided beam. An object of the present invention is to provide an optical unit capable of individually correcting the emission angle of a laser beam and a laser marking device equipped with the optical unit.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a first wedge prism made of a light transmitting body such as glass or plastic, and means for holding the first wedge prism so as to be rotatable about a predetermined axis. A second wedge prism made of a light transmitting body disposed close to or in close contact with the first wedge prism, and the second wedge prism being independent of the first wedge prism about the predetermined axis. Means for rotatably holding the beam, the beam incident on the first wedge prism is emitted from the second wedge prism, and the first and second wedge prisms are independently controlled. There is one feature in that the angle of the output beam is corrected by rotating the angle of.
[0010]
Another feature of the present invention is that it has a means for fixing one of the first and second wedge prisms and rotating the other about a predetermined axis, and the beam incident on the first wedge prism is converted to a first beam. The second wedge prism is configured to emit light, and the first or second wedge prism is rotated at a desired angle to correct the angle of the emitted beam.
[0011]
Another feature of the present invention is to have a wedge prism made of a light transmitting body such as glass or plastic, and a means for holding the wedge prism so as to be rotatable about a predetermined axis. A light beam is incident on one of the sandwiched surfaces, and the light beam is emitted from the other surface sandwiching the apex angle, and the angle of the emitted beam is corrected by rotating the wedge prism by a desired angle. It has been configured to.
Another feature of the present invention is that the output beam angle correction optical unit is arranged so that each of the prism rotation axes and the z-axis of the xyz coordinate system are parallel to each other, and the angle γ formed by the incident beam and the z-axis to the yz plane. orthogonal projection of gamma _{1 xz} of the orthogonal projection gamma to _{1 yz} and xz planes, when the refractive index of each prism n, was each prism apex angle _{α, -2 ≦ γ 1 yz /} (n-1) α ≦ The prism apex angle α is set so as to satisfy 2-2 ≦ γ _{1 xz} / (n−1) α ≦ 2.
[0012]
Another feature of the present invention is that when the orthogonal projection of the angle β between the output beam and the z-axis in the beam emission angle correction optical unit on the yz plane is β _yz and the orthogonal projection on the xz plane is β _xz ,
β _yz = (n−1) α · (cos φ ₁ + cos φ ₂ ) −γ _{1 yz}
β _xz = (n−1) α · (sin φ ₁ + sin φ ₂ ) −γ _{1 xz}
There to the setting of the installation angle phi ₁ and phi ₂ of each prism with respect to the y-axis so as to satisfy.
Other features and advantages of the present invention will be more clearly understood from the following description of the embodiments.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
(Embodiment 1)
FIG. 1 is a schematic view showing an embodiment of a beam emission angle correcting optical unit according to the present invention. In the figure, reference numeral 2A denotes a first wedge prism made of a light transmitting body such as glass or plastic, and is housed in a prism holder 3A. The first wedge prism 2A is arranged on the laser beam incident side. The prism holder 3A is supported so as to be rotatable around a rotation axis (not shown) provided at a position approximately half the height h of the prism 2A in the direction of the arrow AA 'in FIG. ing.
[0014]
On the other hand, 2B is a second wedge prism made of a light transmitting body such as glass or plastic, and is housed in the prism holder 3B. The second wedge prism 2B is arranged on the laser beam emission side. The prism holder 3B is also supported so as to be rotatable independently of the prism holder 3A about a rotation axis (not shown) provided at a position approximately half the height h of the prism 2B.
[0015]
The first and second wedge prisms 2A and 2B have planes parallel to each other, and a beam emission angle correcting optical unit 1 in which the surfaces are closely arranged is configured. In this embodiment, a glass material BK7 having a refractive index of 1.5 is used as the material of the first and second wedge prisms 2A and 2B.
[0016]
Next, the principle of the beam emission angle correction unit according to the present invention will be described. FIG. 2 shows a case where the first and second wedge prisms 2A and 2B in FIG. 1 are arranged close to or fixedly to form a prism 2 having a predetermined prism apex angle α. First, a deflection angle when a beam passes through the inside of the prism 2 will be described with reference to FIG.
[0017]
Beam B1 from the laser light source (not shown) on the incident surface of the prism 2, it is assumed that incident with a normal to the angle I ₁ of its faces. The incident light passes as a beam B2 is refracted inside the prism 2, is emitted in the direction of the normal line and the angle I ₂ of the emission surface as a beam B3. The angle between the beam B2 and the normal to the entrance surface of the prism 2 is I ₁ , and the angle between the beam B2 and the normal to the exit surface is I ₂ .
Assuming that the refractive index of the prism is n and the refractive index of air is ₁ , sinI ₁ = n · sinI ₁ ′ (1) on the incident side according to Snell's law.
On the output side, n · sinI ₂ = sinI ₂ ′ (2)
Holds.
[0018]
Here, when α is extremely small, I ₁ = n · I ₁ ′ (3) from (1) and (2).
n · I ₂ = I ₂ ′ (4)
It becomes.
Next, when the angle between the incident beam B1 and the output beam B3 is defined as “a deflection angle δ”,

Is obtained. That is,
Deflection angle δ = (refractive index of prism-1) × (prism vertical angle) (6)
Is represented by
[0019]
Next, as shown in FIG. 3, consider a case where the prism 2 is placed such that the vertical plane of the prism 2 having the vertical plane is parallel to the xy plane. The prism 2 can be rotated by an arbitrary angle φ about the rotation axis AA ′. Here, the rotation axis AA 'is parallel to the z-axis. In the initial state, the rotation angle φ of the prism 2 is 0 °.
[0020]
Now, consider the orthogonal projection of the normal on the prism slope onto the xz plane and the yz plane.
[0021]
If the prism rotation angle is φ and the vertex angle of the prism is α,
The formula for the orthogonal projection of the normal onto the yz plane is y = tanα · cosφ · z
Therefore, the orthogonal projection of the apex angle is tan ^{- 1} (tan α · cos φ) ≒ α · cos φ.
Therefore, from equation (6), the _deflection angle _{δφyz on the} yz plane is
_δφyz = (n−1) α · cosφ (7) is obtained.
[0022]
Similarly, the equation of the orthogonal projection of the normal onto the xz plane is x = tanα · sinφ · z
Because it is, the orthogonal projection of the apex angle ^{tan -} a 1 (tanα · sinφ) ≒ α · sinφ.
Therefore, from equation (6), the _deflection angle _{δφxz on the} xz plane is _δφxz = (n−1) α · sinφ (8).
[0023]
Also, two types of prisms 2A and 2B the beam B1 is incident at an incidence angle I ₁ a prism which combines the outgoing beam B3 is the reference axis of the apex angle alpha ₁ and alpha ₂ as shown in FIG. 4 (where x-axis) Assuming that β is β, β = δ−I ₁ + α _{1 as} is clear from the drawing. Since the incident beam B1 is the reference axis and forming the angle and _{γ γ = I 1 -α 1 β} = δ- (γ + α 1) + α 1
= Δ-γ
Holds. That is, β = (combination prism deflection angle) − (angle between reference axis and incident beam) (9)
Is represented by
[0024]
On the other hand, when the deflection angle obtained by deflection angle obtained by the apex angle alpha ₁ of the prism 2A at [delta] ₁ apex angle alpha ₂ of the prism 2B and [delta] _2, the deflection angle [delta] obtained by combining the prism δ = δ _{1 +} δ ₂ (10) given by
[0025]
Now, consider a case where two prisms having both apex angles of α are combined.
Incident beam side of the prism phi _1, yz plane component of the deflection angle in the case where the outgoing beam side of the prism is rotated by phi ₂ is (7) ₁ from [delta] _phi formula _{yz = (n-1) α} · cosφ 1 ( 11)
_{δ φ 2 yz = (n-} 1) α · cosφ 2 (12)
From equation (10), the _deflection angle _δφyz of the combination prism is _δφyz = (n−1) α · cosφ ₁ + (n−1) α · cosφ ₂ (13)
Similarly, the xz plane component is expressed by δ _{φ 1 xz} = (n−1) α · sin φ ₁ (14) from Expression (8).
δ _{φ 2x z} = (n−1) α · sin φ ₂ (15)
From equation (10), the _deflection angle _δφxz of the combination prism is _δφxz = (n−1) α · sinφ ₁ + (n−1) α · sinφ ₂ (16)
Therefore, the yz-plane component of the angle β formed by the output beam with respect to the reference axis (here, the z-axis) is obtained from the equations (13) and (9).

It becomes.
Similarly, the xz plane component of the angle β formed by the output beam with respect to the reference axis (here, the z axis) is β _xz = (n−1) α · sin φ ₁ + (n−1) according to equations (16) and (9). α · sin φ ₂ -γ _{1 xz}
= (N−1) α · (sinφ ₁ + sinφ ₂ ) −γ _{1 xz} (18)
In order to perform the angle correction so that the angle between the output beam and the reference axis becomes 0 ° when the incident beam forms an angle with the reference axis, β _yz = 0 in the equations (17) and (18). β _xz = 0.
That is, cos φ ₁ + cos φ ₂ = γ _{1 yz} / (n−1) α (19)
sin φ ₁ + sin φ ₂ = γ _{1 xz} / (n−1) α (20)
Are satisfied at the same time. At this time, φ can take from 0 ° to 360 °,
Since −2 ≦ cosφ ₁ + cosφ ₂ ≦ 2,
−2 ≦ γ _{1 yz} / (n−1) α ≦ 2. That is, -2 (n-1) α ≦ γ 1 yz ≦ 2 (n-1) α (21). Similarly, −2 (n−1) α ≦ γ _{1 xz} ≦ 2 (n−1) α (22).
Generally, the refractive index of glass or plastic material is in the range of 1.45 ≦ n ≦ 1.90, but practically a material of about 1.5 is often used. Therefore (21) and _{(22) -α ≦ γ 1 yz} ≦ Substituting n = 1.5 in the formula alpha (23)
And −α ≦ γ _{1 xz} ≦ α (24).
That is, it can be seen that if γ _{1 yz} and γ _{1 xz} are smaller than the prism apex angle α, it is possible to completely correct the angle to 0 °. The rotation angle of the prism at that time can be obtained from Expressions (19) and (20).
In the present embodiment, BK7 (refractive index n = 1.5), which is general optical glass, is used as a prism material, and two prisms having a vertex angle α of 1 ° are used to correct the angle of the output beam. A specific description will be given of the case where the operation is performed.
[0026]
Now, the angles γ formed by the incident beam with respect to the reference axis are respectively γ _{1 yz} = 0.05 ° γ _{1 xz} = 0.5 °, and these numerical values are calculated in the expressions (19) and (20) to obtain cos φ. ₁ + cosφ ₂ = 0.05 / (1.5-1) · 1
sinφ ₁ + sinφ ₂ = 0.5 / (1.5-1) · 1
φ ₁ = 24.46 ° φ ₂ = 144.12 ° is obtained.
That is, when the angle between the incident beam and the reference axis is γ _{1 yz} = 0.05 ° γ _{1 xz} = 0.5 °, the incident-side prism is rotated by 24.46 ° and the output-side prism is rotated by 144.12 °. By arranging it at the position, the angle between the output beam and the reference axis can be corrected to 0 °.
(Embodiment 2)
FIG. 7 shows a second embodiment of the optical unit according to the present invention. In this optical unit 1, a first wedge prism 2A and a second wedge prism 2B are arranged close to or in close contact with each other as in FIG. 1, but a holder 3A holding the first wedge prism 2A is fixedly arranged. Only the holder 3B holding the second wedge prism 2B is held so as to be able to rotate about the axis AA 'in the direction of the arrow in the figure.
The case of this embodiment in which only the emission-side wedge prism 2B is rotated to correct the emission beam angle corresponds to the case where φ ₁ = 0 ° in Expressions (17) and (18).
That is,
β _yz = (n−1) α · (1 + cos φ ₂ ) −γ _{1 yz} (25)
β _xz = (n−1) α · sin φ ₂ −γ _{1 xz} (26)
Here, when β _yz and β _xz become 0 °, if β _yz = 0 β _xz = 0 in the above equation, 1 + cos φ ₂ = γ _{1 yz} / (n−1) α
sinφ ₂ = γ _{1 xz} / (n−1) α
Since phi ₂ is to be taken to 0 ° to 360 °,
0 ≦ γ _{1 yz} / (n−1) α ≦ 2
−1 ≦ γ _{1 xz} / (n−1) α ≦ 1
That is, 0 ≦ γ _{1 yz} ≦ 2 (n−1) α (27)
− (N−1) α ≦ γ _{1 xz} ≦ (n−1) α (28)
(27) and (28) Substituting n = 1.5 in the formula _{0 ≦ γ 1 yz ≦ α (} 29)
−0.5α ≦ γ _{1 xz} ≦ 0.5α (30)
That is, when only the emission side prism 2B of the two prisms 2A and 2B is rotated to correct the output beam angle, either the yz plane component or the xz plane component of the output beam B3 may be corrected to 0 °. It is possible. At this time, it is necessary to satisfy the relations of the equations (29) and (30) between the angle γ formed by the incident beam B1 with the reference axis and the prism apex angle.
[0027]
In the present embodiment, BK7 (refractive index n = 1.5) is used as the prism material, and two prisms (2A and 2B) having an apex angle α of 1 ° are used, and only the exit-side prism 2B is rotated. A case in which the angle of the output beam (yz plane component) is corrected by using this method will be specifically described. Now, the angle γ formed by the incident beam B1 with respect to the reference axis is γ _{1 yz} = 0.05 °, and these values are calculated in the equation (25) to obtain 0 = (1.5−1) · 1 · (1 + cos φ). ₂ ) -0.05
cos φ ₂ = 154.16 ° is obtained.
That is, when the angle formed by the incident beam B1 and the reference axis is γ _{1 yz} = 0.05 °, β _yz is corrected to 0 ° by disposing the exit-side prism 2B at a position rotated by 154.16 °. It becomes possible.
(Embodiment 3)
FIG. 8 shows a third embodiment of the optical unit according to the present invention, in which one wedge prism 2 is held by holders 3A and 3B, and this wedge prism 2 can rotate around the AA 'axis. Is configured.
When correcting the output beam angle using one prism 2, in equation (17), (n-1) α · cosφ ₁ = 0
And (18) corresponds to the case where (n-1) α · sinφ ₁ = 0.
That is,
β _yz = (n−1) α · cos φ ₂ −γ _{1 yz} (31)
β _xz = (n−1) α · sin φ ₂ −γ _{1 xz} (32)
Here, when β _yz and β _xz become 0 °, if β _yz = 0 and β _xz = 0, cos φ ₂ = γ _{1 yz} / (n−1) α
sinφ ₂ = γ _{1 xz} / (n−1) α
Since phi ₂ is to be taken to 0 ° to 360 °,
−1 ≦ γ _{1 yz} / (n−1) α ≦ 1
−1 ≦ γ _{1 xz} / (n−1) α ≦ 1
That is, − (n−1) α ≦ γ _{1 yz} ≦ (n−1) α (33)
− (N−1) α ≦ γ _{1 xz} ≦ (n−1) α (34)
(33) and (34) Substituting n = 1.5 in the formula If _{-0.5α ≦ γ 1 yz ≦ 0.5α (} 35)
−0.5α ≦ γ _{1 xz} ≦ 0.5α (36)
That is, when correcting the output beam angle using only one prism, it is possible to correct either the yz plane component or the xz plane component of the output beam B3 to 0 °. At this time, it is necessary to satisfy the relations of the equations (35) and (36) between the angle γ formed by the incident beam B1 with the reference axis and the vertex angle of the prism.
[0028]
In the present embodiment, BK7 (refractive index n = 1.5) is used as a prism material, one prism having a vertex angle α of 1 ° is used, and the prism is rotated to output a beam (yz plane component). The case where the angle correction is performed will be specifically described. Now, the angle γ formed by the incident beam with respect to the reference axis is γ _{1 yz} = 0.05 °, and these numerical values are calculated in the equation (31) to obtain 0 = (1.5−1) · 1 · cos φ ₂ − 0.05
cos φ ₂ = 84.26 ° is obtained.
That is, when the angle between the incident beam and the reference axis is γ _{1 yz} = 0.05 °, β _yz can be corrected to 0 ° by disposing the prism at a position rotated by 84.26 °. Become.
(Embodiment 4)
An embodiment in which the beam emission angle correcting optical unit according to the present invention is mounted on a laser marking device will be described. As shown in FIG. 5, the laser marking device 10 basically includes an optical system 14 for generating line light and a support mechanism 15 for keeping the optical system horizontal. FIG. 6 schematically shows an example of the line light generating optical system 14.
[0029]
A laser beam emitted from a semiconductor laser 16 arranged horizontally with respect to the laser marking device main body is converted by a collimator lens 17 into collimated light (parallel light) B1 having a circular beam cross-sectional shape. In the present embodiment, the beam diameter of the collimated light B1 is set to be 2 mm. Further, the beam splitter 4 is used in the optical system 14, and splits the incident light B1 into three lights of uniform intensity. That is, in this embodiment, the beam splitter 4 is formed by bonding three members such as glass or plastic which transmit light, and has a rectangular parallelepiped shape. A first light separation surface 41 is formed on a bonding surface of the first member and the second member. That is, the incident light is separated by the light separation surface 41 into transmitted light and reflected light.
[0030]
Further, a second light separation surface 42 is formed on a bonding surface of the second member and the third member. The reflected light travels inside the beam splitter 4 and is further separated into reflected light and transmitted light at the second light separation surface 42, so that three branched lights can be obtained. Therefore, three line lights can be obtained by arranging the rod lenses 51, 52, 53 on the optical path of each light beam.
Here, since the beam splitter 4 always has a processing error, the exit angle of the split light includes a slight error. However, in the case of a laser marking device, the pointing accuracy of the line light is strictly specified. For example, it is necessary to irradiate the line light and to keep the pointing accuracy within 1 mm within 10 m. In order to keep the accuracy of 1 mm at 10 m, the angle between the light emitted from the beam splitter 4 and the ideal horizontal line (x-axis) must be within 0.005 °. In other words, when the angle formed by each split light with the ideal line exceeds 0.005 °, correction is necessary. In this embodiment, beam emission angle correcting optical units 1a, 1b, and 1c are arranged on each optical path of the light beam emitted from the beam splitter 4. By arranging the rod lenses 51, 52, 53 after the angle correcting optical units 1a, 1b, 1c, the angle error of the line light generated can be set to 0, and can be matched with the ideal line.
Now, an example of one of the light beams emitted from the beam splitter 4 will be described. If the beam incident on the beam emission angle correcting optical unit 1a has an angular error of γ _{1 yz} = 0.05 ° and γ _{1 xz} = 0.5 ° with respect to the reference axis, these numerical values are expressed by the following equation (19). Cos φ ₁ + cos φ ₂ = 0.05 / (1.5-1) · 1
sinφ ₁ + sinφ ₂ = 0.5 / (1.5-1) · 1
φ ₁ = 24.46 ° φ ₂ = 144.12 ° is obtained.
That is, the angle formed by the output beam and the reference axis is corrected to 0 ° by arranging the incident-side prism of the beam output-angle correcting optical unit 1a at a position rotated by 24.46 ° and the output-side prism by 144.12 °. Becomes possible. Similarly, the angle of the remaining branched light can be corrected using the beam emission angle correction optical units 1b and 1c. As a result, the angle error of the line light generated through each of the rod lenses 51, 52, 53 can be set to 0, and can be matched with the ideal line.
[0031]
【The invention's effect】
As described above, by using the beam emission angle correcting optical unit according to the present invention, the beam emission angle can be corrected by a simple method. Also, by mounting the beam emission angle correcting optical unit according to the present invention on the optical system of the laser marking device, it is possible to easily obtain line light with very high pointing accuracy. It has become possible to generate the outgoing laser line light. As a result, it has become possible to obtain a laser marking device for irradiating a plurality of lines at a low cost, which was conventionally very expensive.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a first embodiment of a beam emission angle correcting optical unit according to the present invention.
FIG. 2 is a diagram showing the principle of angle correction by the beam emission angle correction optical unit of the present invention.
FIG. 3 is a schematic diagram showing an example of a prism arrangement of the beam emission angle correcting optical unit of the present invention.
FIG. 4 is a view showing a beam deflection effect by a combination prism. FIG. 5 is a schematic view of a laser marking device equipped with a beam emission angle correcting optical unit of the present invention.
FIG. 6 is a schematic diagram of a line light generating optical system in the laser marking device of the present invention.
FIG. 7 is a schematic view showing a second embodiment of the beam emission angle correcting optical unit according to the present invention.
FIG. 8 is a schematic view showing a third embodiment of the beam emission angle correcting optical unit according to the present invention.
[Explanation of symbols]
1, 1a, 1b, 1c: beam emission angle correcting optical units 2A, 2B, 2: wedge prisms 3A, 3B: prism holder 4, beam splitter 10, laser marking device 14, line light generating optical system 15, support system 16. : Semiconductor laser 17: Collimating lenses 41 and 42: Light separating surfaces 51, 52 and 53: Rod lenses

Claims (14)

A first wedge prism made of a light transmitting body such as glass or plastic; a means for holding the first wedge prism so as to be rotatable about a predetermined axis; And a means for holding the second wedge prism rotatably about the predetermined axis independently of the first wedge prism. , The beam incident on the first wedge prism is emitted from the second wedge prism, and the angle of the emitted beam is corrected by independently rotating the first and second wedge prisms by a desired angle. And a beam emission angle correcting optical unit. A first wedge prism made of a light transmitting body such as glass or plastic, a first holder for holding the first wedge prism, and light arranged close to or in close contact with the first wedge prism A second wedge prism made of a transmitting body, a second holder for holding the second wedge prism, and one of the first and second wedge prisms are fixed, and the other is rotated about a predetermined axis. Moving means for moving the beam incident on the first wedge prism from the second wedge prism and emitting the beam by rotating the first or second wedge prism by a desired angle. A beam emission angle correction optical unit for correcting a beam angle. It has a wedge prism made of a light transmitting body such as glass or plastic, and means for holding the wedge prism rotatably about a predetermined axis. Beam emission angle correction, wherein the light beam is emitted from the other surface sandwiching the apex angle and the angle of the emission beam is corrected by rotating the wedge prism by a desired angle. Optical unit. 3. The beam emission angle correcting optical unit according to claim 1, wherein the vertex angle of the first wedge prism is equal to the vertex angle of the second wedge prism. 3. The beam emission angle correcting optical unit according to claim 1, wherein a vertex angle of the first wedge prism and a vertex angle of the second wedge prism are different. 2. The output beam angle correcting optical unit according to claim 1, wherein the rotation axis of the first and second prisms and the z-axis of the xyz coordinate system are arranged in parallel, and the angle γ formed by the incident beam and the z-axis is shifted to the yz plane. when the orthogonal projection of the gamma ₁ orthogonal projection of the gamma _{1 xz} to _yz and xz plane, the refractive index of each prism is n, each prism apex angle alpha _{of, -2 ≦ γ 1 yz / (} n-1) α _{≦ 2 -2 ≦ γ 1 xz /} (n-1) beams output angle correcting optical unit, characterized in that setting each prism apex angle alpha so as to satisfy the alpha ≦ 2. In claim 6, when the orthogonal projection of the angle β between the output beam and the z-axis in the beam emission angle correcting optical unit on the yz plane is β _yz and the orthogonal projection on the xz plane is β _zz , β _yz = (n -1) α · (cos φ ₁ + cos φ ₂ ) -γ _{1 yz}
β _xz = (n−1) α · (sin φ ₁ + sin φ ₂ ) −γ _{1 xz}
Beam emission angle correction optical unit is characterized in that setting the installation angle phi ₁ and phi ₂ of each prism with respect to the y-axis so as to satisfy. A light source composed of a semiconductor laser, an optical element for converting light emitted from the light source to collimated light, an optical unit for beam emission angle correction for finely adjusting the emission angle of the collimated light, and a collimated light having an emission angle corrected A laser marking device having an optical system for generating line light, wherein the beam emission angle correcting optical unit includes a first wedge prism made of a light transmitting body such as glass or plastic, and the first wedge. Means for holding the prism so as to be rotatable about a predetermined axis, a second wedge prism made of a light transmitting body disposed close to or in close contact with the first wedge prism, and the second wedge prism Means for rotating the first wedge prism about the predetermined axis independently of the first wedge prism. Wherein the beam is emitted from the second wedge prism, and the angle of the emitted beam is corrected by independently rotating the first and second wedge prisms by a desired angle. apparatus. A light source composed of a semiconductor laser, an optical element for converting light emitted from the light source to collimated light, an optical unit for beam emission angle correction for finely adjusting the emission angle of the collimated light, and a collimated light having an emission angle corrected A laser marking device having an optical system for generating line light, wherein the beam emission angle correcting optical unit includes a first wedge prism made of a light transmitting body such as glass or plastic, and the first wedge. A first holder for holding the prism, a second wedge prism made of a light transmitting body disposed close to or in close contact with the first wedge prism, and a second holder for holding the second wedge prism And a means for fixing one of the first and second wedge prisms and rotating the other about a predetermined axis. A beam incident on the beam is emitted from the second wedge prism, and the angle of the emitted beam is corrected by rotating the first or second wedge prism by a desired angle. Laser marking device. A light source composed of a semiconductor laser, an optical element for converting light emitted from the light source to collimated light, an optical unit for beam emission angle correction for finely adjusting the emission angle of the collimated light, and a collimated light having an emission angle corrected A laser marking device including an optical system that generates line light, wherein the beam emission angle correcting optical unit includes a wedge prism made of a light transmitting body such as glass or plastic, and the wedge prism having a predetermined axis. Having means for rotatably holding at the center, the light beam is incident on one surface sandwiching the apex angle of the wedge prism, and the light beam is emitted from the other surface sandwiching the apex angle, A laser marking device which performs angle correction of an output beam by rotating the wedge prism at a desired angle. 9. The output beam angle correcting optical unit according to claim 8, wherein the first and second prism rotation axes and the z-axis of the xyz coordinate system are arranged in parallel, and the angle γ formed by the incident beam and the z-axis is changed to a yz plane. when the orthogonal projection of the gamma ₁ orthogonal projection of the gamma _{1 xz} to _yz and xz plane, the refractive index of each prism is n, each prism apex angle alpha _{of, -2 ≦ γ 1 yz / (} n-1) α _{≦ 2 -2 ≦ γ 1 xz /} (n-1) laser marking apparatus characterized by setting the alpha each prism apex angle so as to satisfy the alpha ≦ 2. In claim 11, when the orthogonal projection of the angle β between the output beam and the z-axis in the beam emission angle correcting optical unit on the yz plane is β _yz and the orthogonal projection on the xz plane is β _xz , β _yz = (n -1) α · (cos φ ₁ + cos φ ₂ ) -γ _{1 yz}
β _xz = (n−1) α · (sin φ ₁ + sin φ ₂ ) −γ _{1 xz}
Laser marking apparatus characterized by setting the installation angle phi ₁ and phi ₂ of each prism with respect to the y-axis so as to satisfy. In claim 8, the orthogonal projection of the angle γ between the incident beam to the beam exit angle correction optical unit and the z-axis on the yz plane and the orthogonal projection on the γ _{1 yz} and xz planes is defined as the refractive index of each prism γ _{1 xz} n, when the apex angle of each prism is α,
−1 ≦ γ _{1 yz} / (n−1) α ≦ 1 −1 ≦ γ _{1 xz} / (n−1) α ≦ 1
A laser marking device having a prism apex angle α satisfying the following. In claim 13, when the orthogonal projection of the angle β between the output beam from the beam emission angle correction optical unit and the z-axis on the yz plane is β _yz and the orthogonal projection on the xz plane is β _xz ,
β _yz = (n−1) α · cos φ−γ _{1 yz}
β _xz = (n−1) α · sin φ−γ _{1 xz}
A laser marking device characterized in that the installation angle φ of each prism with respect to the y-axis is set so as to satisfy the following.

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