JP2013061564A - Optical deflection element and optical deflector - Google Patents

Optical deflection element and optical deflector Download PDF

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JP2013061564A
JP2013061564A JP2011201106A JP2011201106A JP2013061564A JP 2013061564 A JP2013061564 A JP 2013061564A JP 2011201106 A JP2011201106 A JP 2011201106A JP 2011201106 A JP2011201106 A JP 2011201106A JP 2013061564 A JP2013061564 A JP 2013061564A
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polarization inversion
optical
light
deflection
deflection region
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Atsushi Sakai
篤 坂井
Shuichi Suzuki
修一 鈴木
Tsuyoshi Hashiguchi
強 橋口
Atsushi Nakagawa
淳 中川
Kazuhiko Tsukamoto
和彦 塚本
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Ricoh Co Ltd
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  • Optical Modulation, Optical Deflection, Nonlinear Optics, Optical Demodulation, Optical Logic Elements (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide an optical deflection element capable of suppressing strain at the boundary between a polarization-inversion part and a non-polarization-inversion part in a deflection region of an optical crystal to suppress the occurrence of photorefractive effect, and an optical deflector.SOLUTION: Triangular polarization-inversion parts 2a and triangular non-polarization-inversion parts 2b are alternately formed in a non-deflection region B of a substrate made of an optical crystal 2 through which light from a light source not illustrated does not pass, as in the case of a light deflection region A through which light from the light source passes. By thus alternately forming the polarization-inversion parts 2a and non-polarization-inversion parts 2b in the non-deflection region B, an expansion/contraction amount can be reduced compared with the case in which the non-deflection region B is made of only a non-polarization-inversion part. As a result, the influence of the expansion/contraction of the non-deflection region B on the expansion/contraction of the deflection region A is reduced and the strain at the boundary between the polarization-inversion parts 2a and non-polarization-inversion parts 2b of the deflection region A can be suppressed.

Description

本発明は、光偏向素子および光偏向装置に関するものである。   The present invention relates to an optical deflection element and an optical deflection apparatus.

特許文献１には、電気光学効果を有する光学結晶からなる光偏向素子を用いた光偏向器が記載されている。
この光学結晶は、ニオブ酸リチウム結晶中に分極反転させた三角形状（プリズム形状）の分極反転部と分極反転させていない非分極反転部とが、光源からの光を通過させながら光を偏向する偏向領域に光進行方向に交互に形成されている。また、結晶の上面と下面とにそれぞれ電極が設けられている。電極間に電圧を印加すると、ポッケルス効果により、光学結晶の屈折率が変化する。このとき、分極反転部と非分極反転部との屈折率の変化の方向が異なる。具体的に説明すると、例えば、分極反転部の屈折率が、電圧印加前に比べて減少する方向に変化する場合、非分極反転部の屈折率は、電圧印加前に比べて増加する方向に変化する。このような非分極反転部と分極反転部との屈折率の違いから、分極反転部と非分極反転部との境界で光ビームが所定角度偏向される。そして、複数の非分極反転部と分極反転部との境界を通過することで、光学結晶へ入射した光ビームを設定された偏角角度に偏向して、光学結晶から出射する。 Patent Document 1 describes an optical deflector using an optical deflection element made of an optical crystal having an electro-optic effect.
In this optical crystal, a triangular (prism-shaped) domain-inverted portion whose polarization is inverted in a lithium niobate crystal and a non-polarized domain-inverted portion that deflects light while deflecting light from the light source. They are alternately formed in the deflection region in the light traveling direction. Electrodes are provided on the upper and lower surfaces of the crystal, respectively. When a voltage is applied between the electrodes, the refractive index of the optical crystal changes due to the Pockels effect. At this time, the direction of change in the refractive index is different between the polarization inversion part and the non-polarization inversion part. More specifically, for example, when the refractive index of the domain-inverted part changes in a direction that decreases compared to before voltage application, the refractive index of the non-polarized-inversion part changes in a direction that increases compared to before voltage application. To do. Due to the difference in refractive index between the non-polarization inversion part and the polarization inversion part, the light beam is deflected by a predetermined angle at the boundary between the polarization inversion part and the non-polarization inversion part. Then, the light beam incident on the optical crystal is deflected to a set declination angle by passing through the boundaries between the plurality of non-polarization inversion portions and the polarization inversion portions, and is emitted from the optical crystal.

上記光学結晶に電圧を印加すると、ニオブ酸リチウムの光学結晶は、圧電効果により伸長または縮小する。このとき、分極反転部と非分極反転部とで伸縮の方向が異なり、分極反転部と非分極反転部と境界の部分で大きな歪みが生じる。結晶内に歪が生じると結晶内での欠陥準位が生じる。このような状態である程度の強度を持つ波長が短い光が結晶内に照射されると、照射対象物に照射された光ビームのビームスポット径が歪む所謂フォトリフラクション現象が生じてしまう。   When voltage is applied to the optical crystal, the optical crystal of lithium niobate expands or contracts due to the piezoelectric effect. At this time, the direction of expansion / contraction differs between the polarization inversion part and the non-polarization inversion part, and a large distortion occurs at the boundary between the polarization inversion part and the non-polarization inversion part. When distortion occurs in the crystal, a defect level is generated in the crystal. In this state, when light having a certain intensity and a short wavelength is irradiated into the crystal, a so-called photorefractive phenomenon occurs in which the beam spot diameter of the light beam irradiated to the irradiation object is distorted.

上述のフォトリフラクション現象は、次のようにして発生する。光学結晶に光ビームを照射すると光学結晶内に存在する欠陥準位からキャリア（電荷）が励起される。このキャリアは、電極間の電界の影響により移動（キャリアドリフト）して結晶内の別の欠陥準位にトラップされる。また、その箇所に他の欠陥準位で発生して移動してきたキャリアもトラップされ、その箇所にキャリアが集まり、一種の空間電荷層が形成される。この空間電荷層が光学結晶の内部電界を形成し、その内部電界が、電極間に印加した外部電界の作用を阻害し、光学結晶内部の屈折率を変化させる。その結果、光学結晶内部で光が散乱され、光ビームが歪む。これが、フォトリフラクション現象である。   The above-described photorefractive phenomenon occurs as follows. When the optical crystal is irradiated with a light beam, carriers (charges) are excited from defect levels existing in the optical crystal. The carriers move (carrier drift) due to the influence of the electric field between the electrodes and are trapped in another defect level in the crystal. In addition, carriers generated and moved in other defect levels at that location are also trapped, and carriers gather at that location to form a kind of space charge layer. This space charge layer forms an internal electric field of the optical crystal, and the internal electric field inhibits the action of the external electric field applied between the electrodes and changes the refractive index inside the optical crystal. As a result, light is scattered inside the optical crystal, and the light beam is distorted. This is the photorefractive phenomenon.

そして、上述の光学結晶においては、分極反転部は光源の光が通過する偏向領域だけに形成されており、光源の光が通過しない光学結晶の非偏向領域は、非分極反転部のみである。従って、偏向領域における非分極反転部が、非偏向領域の非分極反転部とともに伸長または収縮するため、偏向領域における非分極反転部の収縮量または伸長量が大きくなる。その結果、分極反転部と非分極反転部との境界の歪みが大きくなり、上述した欠陥準位が生じやすく、フォトリフラクション現象が発生しやすいという課題があった。   In the above-described optical crystal, the polarization inversion portion is formed only in the deflection region through which the light from the light source passes, and the non-deflection region in the optical crystal through which the light from the light source does not pass is only the non-polarization inversion portion. Therefore, since the non-polarization inversion part in the deflection region expands or contracts together with the non-polarization inversion part in the non-deflection region, the amount of contraction or extension of the non-polarization inversion part in the deflection region increases. As a result, there is a problem in that the distortion at the boundary between the polarization inversion portion and the non-polarization inversion portion is increased, the above-described defect level is likely to occur, and the photorefractive phenomenon is likely to occur.

本発明は以上の課題に鑑みなされたものであり、その目的は、光学結晶の偏向領域における分極反転部と非分極反転部との境界の歪みを抑制して、フォトリフラクション現象の発生を抑制することができる光偏向素子および光偏向装置を提供することである。   The present invention has been made in view of the above problems, and its purpose is to suppress the distortion of the boundary between the polarization inversion portion and the non-polarization inversion portion in the deflection region of the optical crystal, thereby suppressing the occurrence of the photorefractive phenomenon. It is an object to provide an optical deflecting element and an optical deflecting device which can be used.

上記目的を達成するために、請求項１の発明は、光源の光が通過するときに光を偏向する光偏向領域に分極反転部と非分極反転部とが光進行方向に交互に形成された光学結晶を有する光偏向素子において、上記光学結晶の非光偏向領域の所定の箇所に、分極反転部を形成したことを特徴とするものである。   In order to achieve the above object, according to the first aspect of the present invention, a polarization inversion portion and a non-polarization inversion portion are alternately formed in the light traveling direction in a light deflection region that deflects light when light from a light source passes. In the optical deflection element having an optical crystal, a polarization inversion portion is formed at a predetermined position in the non-optical deflection region of the optical crystal.

本発明によれば、光学結晶の非光偏向領域にも、分極反転部を形成したことにより、光学結晶に電界を形成したとき、非光偏向領域の分極反転部が、非偏向領域の非分極反転部と逆方向に変形し、非光偏向領域の非分極反転部の収縮または伸長を抑制することができる。その結果、非偏向領域の非分極反転部の収縮または伸長に引きずられて、偏向領域の非分極反転部が伸長または収縮するのを抑制することができる。従って、偏向領域の非分極反転部の伸長または収縮量を、非偏向領域が非分極反転部のみで形成されたものよりも抑制することができる。これにより、偏向領域の分極反転部と非分極反転部と境界の歪みを、非偏向領域が非分極反転部のみで形成されたものよりも少なくすることができ、偏向領域の分極反転部と非分極反転部と境界に欠陥準位が生じるのを抑制することができる。よって、非偏向領域が非分極反転部のみで形成されたものよりもフォトリフラクション現象の発生を抑制することができる。   According to the present invention, since the polarization inversion portion is also formed in the non-optical deflection region of the optical crystal, when the electric field is formed in the optical crystal, the polarization inversion portion of the non-optical deflection region By deforming in the direction opposite to the inversion part, it is possible to suppress contraction or extension of the non-polarization inversion part of the non-light deflection region. As a result, it is possible to suppress expansion or contraction of the non-polarization inversion part of the deflection region due to the contraction or expansion of the non-polarization inversion part of the non-deflection region. Therefore, the amount of expansion or contraction of the non-polarization inversion part of the deflection region can be suppressed more than that in which the non-deflection region is formed by only the non-polarization inversion part. Thereby, the distortion of the boundary between the polarization inversion portion and the non-polarization inversion portion in the deflection region can be reduced as compared with the case where the non-deflection region is formed only by the non-polarization inversion portion. It is possible to suppress the generation of defect levels at the domain-inverted portion and the boundary. Therefore, the occurrence of the photorefractive phenomenon can be suppressed as compared with the case where the non-deflection region is formed only by the non-polarization inversion part.

本実施形態に係る光偏向素子の概略構成図。FIG. 2 is a schematic configuration diagram of an optical deflection element according to the present embodiment. 同光偏向素子の断面図。Sectional drawing of the same optical deflection | deviation element. （a）は電圧が印加されていない場合の光学結晶を示した図であり、（ｂ）は分極反転が形成されていない光学結晶に電圧が印加されたときの光学結晶の伸縮を模式的に表した図であり、（ｃ）は、分極反転部が形成されている光学結晶で電圧が印加されたときの光学結晶の伸縮を模式的に表した図。(A) is a diagram showing an optical crystal when no voltage is applied, and (b) schematically shows the expansion and contraction of the optical crystal when a voltage is applied to an optical crystal in which no polarization inversion is formed. It is the figure which represented, (c) is the figure which represented typically the expansion-contraction of the optical crystal when a voltage is applied with the optical crystal in which the polarization inversion part is formed. 光学結晶を支持基板上に形成した光偏向素子の概略構成図。The schematic block diagram of the optical deflection | deviation element which formed the optical crystal on the support substrate. 変形例１の光偏向素子の概略構成図。FIG. 6 is a schematic configuration diagram of an optical deflecting element of Modification 1; 変形例２の光偏向素子の概略構成図。FIG. 10 is a schematic configuration diagram of an optical deflection element according to Modification 2. 光偏向装置の一例を示す概略構成図。The schematic block diagram which shows an example of an optical deflection apparatus.

以下、図面を参照して、本発明の実施の形態を説明する。
図１は本発明の一実施形態に係る光偏向素子１の概略構成例を示す図であり、図２は、光偏向素子１の断面図である。以下の説明では、光軸方向をＸ方向、光偏向素子１の偏向方向（光走査方向）をＹ方向、Ｘ方向およびＹ方向に直交する方向（紙面に対して垂直方向）をＺ方向として、説明する。
本実施形態に係る光偏向素子１は、ニオブ酸リチウムやタンタル酸リチウムなどに代表される酸化物の強誘電性結晶からなる光学結晶２を有している。この光学結晶２でできた基板の図示しない光源からの光が通過する光偏向領域Ａには、複数の分極反転部２ａが光軸方向に並んで形成されている。その結果、光偏向領域Ａには、三角形状の分極反転部２ａと、三角形状の非分極反転部２ｂとが交互に形成されたパターン形状となっている。これら分極反転部２ａは、三角形形状の連鎖で形成されるプリズム型の分極ドメインを分極反転技術によって形成する。分極反転部２ａの三角形状の幅や高さは、偏向角などの素子の仕様によって、適宜決定される。例えば、幅１ｍｍ、高さ２ｍｍの二等辺三角形の形状などである。 Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a diagram illustrating a schematic configuration example of an optical deflection element 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the optical deflection element 1. In the following description, the optical axis direction is the X direction, the deflection direction (optical scanning direction) of the optical deflection element 1 is the Y direction, and the direction perpendicular to the X direction and the Y direction (the direction perpendicular to the paper surface) is the Z direction. explain.
The light deflection element 1 according to the present embodiment has an optical crystal 2 made of a ferroelectric crystal of an oxide typified by lithium niobate or lithium tantalate. A plurality of polarization inversion portions 2a are formed side by side in the optical axis direction in an optical deflection region A through which light from a light source (not shown) of the substrate made of the optical crystal 2 passes. As a result, the light deflection region A has a pattern shape in which triangular polarization inversion portions 2a and triangular non-polarization inversion portions 2b are alternately formed. These polarization inversion parts 2a form prism-type polarization domains formed by triangular chains by a polarization inversion technique. The width and height of the triangular shape of the polarization inversion portion 2a are appropriately determined according to the element specifications such as the deflection angle. For example, the shape is an isosceles triangle having a width of 1 mm and a height of 2 mm.

図２に示すように、光偏向素子１のＸＹ平面に電源１０が接続された電極３が形成されており、電極３で分極反転部２ａを挟み込んでいる。不図示の光源からの光ビームは、光偏向素子１の図中左側の面（ＺＹ平面）から入射し、電極３に挟まれた光学結晶２の偏向領域Ａを透過して、図中右側のＺＹ平面から出射する。   As shown in FIG. 2, an electrode 3 to which a power source 10 is connected is formed on the XY plane of the optical deflection element 1, and the polarization inversion portion 2 a is sandwiched between the electrodes 3. A light beam from a light source (not shown) enters from the left surface (ZY plane) of the light deflection element 1 in the drawing, passes through the deflection region A of the optical crystal 2 sandwiched between the electrodes 3, and passes through the right side of the drawing. The light exits from the ZY plane.

また、本実施形態においては、不図示の光源の光が通過しない非偏向領域Ｂにも、偏向領域Ａに形成された分極反転部２ａと同じ形状の複数の分極反転部２ａが、光軸方向に並んで形成されている。その結果、非偏向領域Ｂにも、偏向領域Ａと同じ三角形状の分極反転部２ａと、三角形状の非分極反転部２ｂとが交互に形成されたパターン形状となっている。これにより、分極反転部２ａと、非分極反転部２ｂとの面積がほぼ等しくなる。   In the present embodiment, a plurality of polarization inversion portions 2a having the same shape as the polarization inversion portions 2a formed in the deflection area A are also provided in the non-deflection region B through which light from a light source (not shown) does not pass. Are formed side by side. As a result, the non-deflection region B also has a pattern shape in which the same triangular polarization inversion portions 2a and triangular non-polarization inversion portions 2b as in the deflection region A are alternately formed. Thereby, the area of the polarization inversion part 2a and the non-polarization inversion part 2b becomes substantially equal.

図１に示すように、光学結晶２の電極３が形成されている部分、つまり電圧が印加される部分の非偏向領域Ｂに分極反転部２ａが形成される。なお、本実施形態においては、各非偏向領域にそれぞれ一列の分極反転部２ａと非分極反転部２ｂとが交互に形成されたパターンを形成しているが、１列以上であってもよい。   As shown in FIG. 1, the polarization inversion part 2a is formed in the non-deflection region B of the part where the electrode 3 of the optical crystal 2 is formed, that is, the part where the voltage is applied. In the present embodiment, each non-deflection region has a pattern in which a row of polarization inversion portions 2a and non-polarization inversion portions 2b are alternately formed, but it may be in one or more rows.

電極３に電源１０からの電圧を印加すると、電極３に挟まれた光学結晶内に電界生じ、その電界の大きさに対応して電気光学効果（ポッケルス効果）により光学結晶の屈折率が変化する。ポッケルス効果は電界に１次比例するので、電界の方向（正負）によって屈折率の変化量も正負に変化する。分極反転部２ａでは結晶軸が１８０度回転しているために、同じ方向に電界が発生していても、分極反転部２ａと非分極反転部２ｂとでの屈折率変化量の符号が異なる。つまり、分極反転部２ａで屈折率が−（Δｎ）変化するように電圧が印加されると、非分極反転部２ｂでは＋（Δｎ）変化するのである。よって、分極反転部２ａと非分極反転部２ｂとに屈折率の差が生じる。このため、分極反転部２ａと非分極反転部２ｂとの境界で光学結晶２の偏向領域Ａを通過する光の進行方向が徐々に変化していき、出力側では、ある偏向角θの出力を得ることができる。   When a voltage from the power source 10 is applied to the electrode 3, an electric field is generated in the optical crystal sandwiched between the electrodes 3, and the refractive index of the optical crystal changes due to the electro-optic effect (Pockels effect) corresponding to the magnitude of the electric field. . Since the Pockels effect is linearly proportional to the electric field, the amount of change in the refractive index also changes positive and negative depending on the direction of the electric field (positive or negative). Since the crystal axis of the polarization inversion part 2a is rotated by 180 degrees, even if an electric field is generated in the same direction, the sign of the refractive index change amount between the polarization inversion part 2a and the non-polarization inversion part 2b is different. That is, when a voltage is applied so that the refractive index changes by − (Δn) in the polarization inversion unit 2a, the non-polarization inversion unit 2b changes by + (Δn). Therefore, a difference in refractive index occurs between the polarization inversion portion 2a and the non-polarization inversion portion 2b. For this reason, the traveling direction of the light passing through the deflection region A of the optical crystal 2 gradually changes at the boundary between the polarization inversion unit 2a and the non-polarization inversion unit 2b. Can be obtained.

光学結晶内に欠陥準位があると、上述したフォトリフラクション現象が発生するおそれがあるため、結晶への不純物のドープなどの方法により抑制される方法が取られている。しかしながら、本実施形態においては、ニオブ酸リチウムやタンタル酸リチウムなどに代表される酸化物の強誘電性結晶からなる光学結晶を用いており、圧電効果も有している。このため、光を偏向させるために結晶２を挟む対極した電極３に電圧を印加すると、光学結晶２は圧電効果によって結晶自体が伸縮する。このとき、分極反転部２ａと、非分極反転部２ｂとの伸縮方向が異なる。その結果、分極反転部２ａと非分極反転部２ｂとの境界に歪みが発生し、分極反転部２ａと非分極反転部２ｂとの間に欠陥準位が生じてしまう。このように欠陥準位が生じると、上述したフォトリフラクション現象が生じ、光偏向素子１から出射された光ビームのビーム形状が歪んでしまう。   If there is a defect level in the optical crystal, the above-described photorefractive phenomenon may occur. Therefore, a method that is suppressed by a method such as doping of impurities into the crystal is used. However, in the present embodiment, an optical crystal made of a ferroelectric crystal of an oxide typified by lithium niobate or lithium tantalate is used and has a piezoelectric effect. For this reason, when a voltage is applied to the opposite electrode 3 sandwiching the crystal 2 to deflect the light, the crystal itself of the optical crystal 2 expands and contracts due to the piezoelectric effect. At this time, the expansion / contraction directions of the polarization inversion part 2a and the non-polarization inversion part 2b are different. As a result, distortion occurs at the boundary between the polarization inversion portion 2a and the non-polarization inversion portion 2b, and a defect level is generated between the polarization inversion portion 2a and the non-polarization inversion portion 2b. When such a defect level occurs, the above-described photorefractive phenomenon occurs, and the beam shape of the light beam emitted from the light deflection element 1 is distorted.

つまり、電圧が印加されない場合にフォトリフラクション現象がほとんど生じない入射光条件またはドーピングされた結晶であっても、結晶の圧電効果による欠陥準位の増加してしまう。このように、欠陥準位が増加すると、光照射により励起されるキャリアも増加してしまい、フォトリフラクション現象が生じてしまう。この伸縮現象は電界に比例した大きさで伸縮を生じるため、偏向角度を大きくした場合、印加する電圧が大きくなるため、その分伸縮の影響が強くなり、より顕著に光のビーム形状歪みが生じる。   In other words, even if the incident light condition or the doped crystal causes almost no photorefractive phenomenon when no voltage is applied, the defect level increases due to the piezoelectric effect of the crystal. Thus, when the defect level increases, the number of carriers excited by light irradiation also increases, and a photorefractive phenomenon occurs. Since this expansion / contraction phenomenon causes expansion / contraction with a magnitude proportional to the electric field, when the deflection angle is increased, the applied voltage increases, so the influence of the expansion / contraction becomes stronger, and the beam shape distortion of light occurs more remarkably. .

そこで、本実施形態においては、上述したように、非偏向領域Ｂにも、分極反転部２ａと非分極反転部２ｂとを交互に形成し、非偏向領域Ｂの伸縮（伸長または収縮）を抑えることで、偏向領域Ａの非分極反転部２ｂの伸縮を抑えることで、偏向領域Ａにおける分極反転部２ａと非分極反転部２ｂとの境界に生じる歪みを抑制している。   Therefore, in the present embodiment, as described above, the polarization inversion portions 2a and the non-polarization inversion portions 2b are alternately formed in the non-deflection region B, and the expansion (extension or contraction) of the non-deflection region B is suppressed. Thus, by suppressing expansion and contraction of the non-polarization inversion portion 2b in the deflection area A, distortion generated at the boundary between the polarization inversion portion 2a and the non-polarization inversion portion 2b in the deflection area A is suppressed.

図３（a）は電圧が印加されていない場合の結晶であり、（ｂ）は分極反転部が形成されていない結晶（全てが非分極反転部）で電圧が印加されたとき、（ｃ）は分極反転部が形成されている結晶で電圧が印加されたときの伸縮を模式的に表した図である。また、以下の説明では、電圧を印加することで図３（ｂ）のように非分極反転部が縮む場合を例に説明する。
図３（ｃ）で示すように分極反転部２ａと非分極反転部２ｂとが交互に形成された場合、分極反転部２ａは伸び、非分極反転部２ｂは、縮むことになる。このとき分極反転部２ａと非分極反転部２ｂとの境界では結晶面が連続である必要があるために、図の実線で記したような形状となり、図３（ｂ）に示すように、一様な結晶軸に電圧を印加した場合と比較して伸縮度を相対的に緩和することができることがわかる。 3A is a crystal when no voltage is applied, and FIG. 3B is a crystal when a voltage is applied to a crystal in which no polarization inversion portion is formed (all are non-polarization inversion portions). FIG. 6 is a diagram schematically showing expansion and contraction when a voltage is applied to a crystal in which a polarization inversion portion is formed. Further, in the following description, an example will be described in which the non-polarized inversion portion contracts as shown in FIG. 3B by applying a voltage.
When the polarization inversion portions 2a and the non-polarization inversion portions 2b are alternately formed as shown in FIG. 3C, the polarization inversion portions 2a are expanded and the non-polarization inversion portions 2b are contracted. At this time, since the crystal plane needs to be continuous at the boundary between the polarization inversion portion 2a and the non-polarization inversion portion 2b, the shape is as indicated by the solid line in the figure, and as shown in FIG. It can be seen that the degree of expansion and contraction can be relatively relaxed compared to the case where a voltage is applied to such a crystal axis.

その結果、非偏向領域Ｂに分極反転部２ａを設けていない場合は、非偏向領域Ｂは、図３（ｂ）に示すように、大きく収縮する。よって、非偏向領域Ｂに分極反転部を設けていない場合、偏向領域Ａの非分極反転部２ｂが、非偏向領域Ｂの収縮の影響を受けて、収縮が大きくなってしまう。その結果、偏向領域Ａの分極反転部２ａと非分極反転部２ｂとの境界の歪みが大きくなり、欠陥準位が生じやすい。   As a result, when the polarization inversion portion 2a is not provided in the non-deflection region B, the non-deflection region B contracts greatly as shown in FIG. Therefore, when the polarization inversion portion is not provided in the non-deflection region B, the non-polarization inversion portion 2b of the deflection region A is affected by the contraction of the non-deflection region B, and the contraction becomes large. As a result, the distortion at the boundary between the polarization inversion portion 2a and the non-polarization inversion portion 2b in the deflection region A increases, and a defect level is likely to occur.

一方、図１、図２に示すように、非偏向領域Ｂに分極反転部２ａと非分極反転部２ｂとを交互に形成することで、非偏向領域Ｂを非分極反転部のみにした場合に比べて、伸縮量を緩和することができる。その結果、この非偏向領域Ｂの伸縮が、偏向領域Ａの伸縮に与える影響が緩和され、偏向領域Ａの分極反転部２ａと非分極反転部２ｂとの境界の歪みを抑制することができる。これにより、偏向領域Ａの分極反転部２ａと非分極反転部２ｂとの境界に欠陥準位が生じるのを抑制することができ、フォトリフラクション現象が生じるのを抑制することができる。   On the other hand, as shown in FIG. 1 and FIG. 2, when the non-deflection region B is only the non-polarization inversion part by alternately forming the polarization inversion parts 2 a and the non-polarization inversion parts 2 b in the non-deflection area B In comparison, the amount of expansion and contraction can be relaxed. As a result, the influence of the expansion / contraction of the non-deflection region B on the expansion / contraction of the deflection region A is mitigated, and distortion at the boundary between the polarization inversion portion 2a and the non-polarization inversion portion 2b of the deflection region A can be suppressed. Thereby, it can suppress that a defect level arises in the boundary of the polarization inversion part 2a and the non-polarization inversion part 2b of the deflection | deviation area | region A, and can suppress that a photo refraction phenomenon arises.

図４は、光学結晶２を支持基板６上に形成した光偏向素子１の概略構成図である。
図４に示すように、支持基板６に接着剤５により、厚さが１００μｍ以下の光学結晶２を接着する。また、電極３による光の吸収を低減するためのバッファ層４を介して電極３を光学結晶２に固定している。
このように、支持基板６に光学結晶２を設けることで、光学結晶２の厚みは１０μｍ程度まで薄くすることが可能となる。このように、光学結晶２の厚みを薄くすることで、所定の角度偏向するために電極間に印加する電圧の大きさを減らすことができる。ある偏向角度に偏向する場合（光学結晶２に同じ電界値を発生させるため）の電圧は、３００μｍの厚さと比較して１０μｍの厚さであれば１／３０に低減でき、１００Ｖ程度で解像点数５０点以上の光偏向素子１を形成することが可能となる。このように低電圧駆動が可能であるため、高速スキャンをするために高周波を電極３に印加する場合の電圧発生回路の負荷が小さくなり、省電力動作も可能となる。 FIG. 4 is a schematic configuration diagram of the optical deflection element 1 in which the optical crystal 2 is formed on the support substrate 6.
As shown in FIG. 4, the optical crystal 2 having a thickness of 100 μm or less is bonded to the support substrate 6 by the adhesive 5. In addition, the electrode 3 is fixed to the optical crystal 2 through a buffer layer 4 for reducing light absorption by the electrode 3.
Thus, by providing the optical crystal 2 on the support substrate 6, the thickness of the optical crystal 2 can be reduced to about 10 μm. Thus, by reducing the thickness of the optical crystal 2, the magnitude of the voltage applied between the electrodes can be reduced in order to deflect at a predetermined angle. The voltage when deflecting at a certain deflection angle (to generate the same electric field value in the optical crystal 2) can be reduced to 1/30 if the thickness is 10 μm compared to 300 μm, and the resolution is about 100V. It becomes possible to form the light deflection element 1 having 50 or more points. Since low voltage driving is possible in this way, the load on the voltage generating circuit when applying a high frequency to the electrode 3 for high-speed scanning is reduced, and power saving operation is also possible.

次に、本実施形態の光偏向素子１の製作方法を説明する。
まず、ニオブ酸リチウム基板（光学結晶２）にリソグラフィー技術によってプリズムをパターニングし、液体電極中で高電圧を印加することでプリズム型（三角形状）の分極反転部２ａを形成する。また、分極反転部２ａと非分極反転部２ｂとが光軸方向に交互に形成されたパターンは、電極３によってカバーされる部分を想定した領域内全面に形成する。その基板（光学結晶２）に、金などの金属による電極層を薄膜形成技術で形成することで電極３を形成する。このとき、裏面には一様に電極３を形成するが、反対側の表面は電極３を所望の面積で形成する。また、図４に示す光偏向素子１の場合は、基板（光学結晶２）に分極反転パターン形成後、五酸化二タンタル（Ｔａ２Ｏ５）によるバッファ層４と、電極３を形成し、この光学結晶２と支持基板６とを接着剤５により張り合わせたのち、研磨などの薄膜化技術によりニオブ酸リチウムを２０μｍまで薄くした光導波路形状を用いる。 Next, a manufacturing method of the light deflection element 1 of the present embodiment will be described.
First, a prism is patterned on a lithium niobate substrate (optical crystal 2) by a lithography technique, and a high voltage is applied in a liquid electrode to form a prism type (triangular) polarization inversion portion 2a. Further, the pattern in which the polarization inversion portions 2 a and the non-polarization inversion portions 2 b are alternately formed in the optical axis direction is formed on the entire surface in the region assuming the portion covered by the electrode 3. The electrode 3 is formed on the substrate (optical crystal 2) by forming an electrode layer made of metal such as gold by a thin film forming technique. At this time, the electrode 3 is uniformly formed on the back surface, but the electrode 3 is formed with a desired area on the opposite surface. In the case of the optical deflection element 1 shown in FIG. 4, after forming a polarization inversion pattern on the substrate (optical crystal 2), a buffer layer 4 made of tantalum pentoxide (Ta 2 O 5 ) and an electrode 3 are formed. After the optical crystal 2 and the support substrate 6 are bonded together with an adhesive 5, an optical waveguide shape in which lithium niobate is thinned to 20 μm by a thinning technique such as polishing is used.

次に、本実施形態の変形例について説明する。   Next, a modification of this embodiment will be described.

［変形例１］
図５は、変形例１の光偏向素子１Ａの概略構成図である。
この変形例１では、電極に対向する非偏向領域Ｂに、光軸方向（Ｘ方向）に対して平行の延びる分極反転部２ａと非分極反転部２ｂとを交互に形成したものである。
このような構成とすることで、非偏向領域Ｂの分極反転部２ａの間隔を、図１に示す構成に比べて狭くすることができる。図１に示すように、三角形状の分極反転部２ａを非偏向領域Ｂに複数並べた構成に比べて、分極反転部２ａの間隔を十分狭くすることができる。例えば、非偏向領域Ｂに分極反転部２ａを等間隔で形成する場合、分極反転技術により１０μｍ程度のピッチで非偏向領域Ｂに分極反転部２ａを形成することができる。また、非偏向領域Ｂの分極反転部２ａの幅と、非分極反転部２ｂの幅を同じとなるように形成した場合は、その幅は５μｍ程度となる。一方、図１に示す構成の場合は、三角形状の分極反転部２ａは数ｍｍオーダのサイズであるので、変形例１の構成とすることで、分極反転部２ａの間隔を十分に小さく形成することが可能である。 [Modification 1]
FIG. 5 is a schematic configuration diagram of an optical deflection element 1A of the first modification.
In the first modification, the polarization inversion portions 2a and the non-polarization inversion portions 2b extending in parallel to the optical axis direction (X direction) are alternately formed in the non-deflection region B facing the electrodes.
By setting it as such a structure, the space | interval of the polarization inversion part 2a of the non-deflection area | region B can be narrowed compared with the structure shown in FIG. As shown in FIG. 1, the interval between the polarization inversion portions 2 a can be made sufficiently narrow as compared with a configuration in which a plurality of triangular polarization inversion portions 2 a are arranged in the non-deflection region B. For example, when the polarization inversion portions 2a are formed in the non-deflection region B at equal intervals, the polarization inversion portions 2a can be formed in the non-deflection region B at a pitch of about 10 μm by the polarization inversion technique. Further, when the width of the polarization inversion portion 2a in the non-deflection region B and the width of the non-polarization inversion portion 2b are formed to be the same, the width is about 5 μm. On the other hand, in the case of the configuration shown in FIG. 1, the triangular polarization inversion portion 2a has a size on the order of several millimeters. Therefore, the configuration of the modification 1 allows the interval between the polarization inversion portions 2a to be sufficiently small. It is possible.

このように十分に細かいサイズで分極反転部２ａを形成した非偏向領域Ｂに電圧を印加すると、前述のように応力による伸縮方向が結晶軸によって異なるため、分極反転部２ａと非分極反転部とで、互いに伸縮を打ち消し合い、非偏向領域Ｂの伸縮量を低減することができる。これにより、非偏向領域Ｂの伸縮の影響が、偏向領域Ａに及ぶのを抑制することができ、偏向領域Ａの分極反転部２ａと非分極反転部２ｂとの境界の歪みの抑制効果を高めることができる。   When a voltage is applied to the non-deflection region B in which the polarization inversion portion 2a is formed in such a sufficiently small size, the expansion and contraction direction due to stress varies depending on the crystal axis as described above. Thus, the expansion and contraction of each other can be canceled out, and the expansion / contraction amount of the non-deflection region B can be reduced. Thereby, it is possible to suppress the influence of expansion / contraction of the non-deflection region B from reaching the deflection region A, and to enhance the effect of suppressing distortion at the boundary between the polarization inversion portion 2a and the non-polarization inversion portion 2b of the deflection region A. be able to.

分極反転部２ａの間隔は、一定である必要はなく、外側に向かって間隔が広くなっていく構造や、狭くなっていく構造、間隔が周期的に変化するような構造でも良い。印加する電圧や、電極３の形状、偏向領域Ａの分極反転部２ａの形状によって非偏向領域Ｂの分極反転部２ａ間の間隔は、適宜決めればよい。   The interval between the polarization inversion parts 2a need not be constant, and may be a structure in which the interval increases toward the outside, a structure in which the interval decreases, or a structure in which the interval changes periodically. The interval between the polarization inversion portions 2a in the non-deflection region B may be appropriately determined according to the voltage to be applied, the shape of the electrode 3, and the shape of the polarization inversion portion 2a in the deflection region A.

［変形例２］
図６は、変形例２の光偏向素子１Ｂの概略構成図である。
この変形例２は、非光偏向領域Ｂに、光軸に対して垂直な分極反転部２ａと非分極反転部２ｂとを交互に形成したものである。
分極反転部２ａのピッチが狭くなると、長く均一に分極反転部２ａを形成することが困難になる場合がある。よって、変形例２に示す構成とすることで、変形例１に示す構成に比べて、分極反転部２ａの長さを短くすることができる。これにより、製作精度（均一な分極反転部）を確保しながら比較的容易な方法で狭い間隔で分極反転部２ａを形成することができる。 [Modification 2]
FIG. 6 is a schematic configuration diagram of an optical deflection element 1B of the second modification.
In the second modification, polarization inversion portions 2a and non-polarization inversion portions 2b perpendicular to the optical axis are alternately formed in the non-light deflection region B.
If the pitch of the domain inversion parts 2a is narrowed, it may be difficult to form the domain inversion parts 2a long and uniformly. Therefore, by adopting the configuration shown in the second modification, the length of the polarization inversion unit 2a can be shortened compared to the configuration shown in the first modification. Thereby, the polarization inversion part 2a can be formed at a narrow interval by a relatively easy method while ensuring manufacturing accuracy (uniform polarization inversion part).

また、この変形例２も非偏向領域Ｂの分極反転部２ａのピッチを十分に狭めることができるので、変形例１と同様、非偏向領域Ｂの伸縮を低減することができる。これにより、非偏向領域Ｂの伸縮の影響が、偏向領域Ａに及ぶのを抑制することができ、偏向領域Ａの分極反転部２ａと非分極反転部２ｂとの境界の歪みの抑制効果を高めることができる。   Further, since the second modification can also sufficiently narrow the pitch of the polarization inversion portions 2a in the non-deflection region B, the expansion / contraction of the non-deflection region B can be reduced as in the first modification. Thereby, it is possible to suppress the influence of expansion / contraction of the non-deflection region B from reaching the deflection region A, and to enhance the effect of suppressing distortion at the boundary between the polarization inversion portion 2a and the non-polarization inversion portion 2b of the deflection region A. be able to.

また、上記では、光の進行方向に対して平行または垂直に延びる分極反転部２ａを形成した変形例を説明したが、非偏向領域Ｂに光の進行方向に対して斜めに延びる分極反転部と非分極反転部とを交互に形成してもよい。このような構成でも、変形例１、２同様、非偏向領域Ｂの分極反転部２ａのピッチを十分に狭めることができ、非偏向領域Ｂの伸縮量を低減することができる。これにより、非偏向領域Ｂの伸縮の影響が、偏向領域Ａに及ぶのを抑制することができ、偏向領域Ａの分極反転部２ａと非分極反転部２ｂとの境界の歪みの抑制効果を高めることができる。   In the above description, the modification example in which the polarization inversion portion 2a extending parallel or perpendicular to the light traveling direction has been described. However, the non-deflecting region B includes a polarization inversion portion extending obliquely with respect to the light traveling direction. You may form a non-polarization inversion part alternately. Even with such a configuration, the pitch of the polarization inversion portions 2a in the non-deflection region B can be sufficiently narrowed and the amount of expansion / contraction of the non-deflection region B can be reduced as in the first and second modifications. Thereby, it is possible to suppress the influence of expansion / contraction of the non-deflection region B from reaching the deflection region A, and to enhance the effect of suppressing distortion at the boundary between the polarization inversion portion 2a and the non-polarization inversion portion 2b of the deflection region A. be able to.

次に、上記光偏向素子１を用いた偏向装置４１について説明する。
図７は、光偏向装置４１の一例を示す概略構成図である。光偏向装置４１は、光源４２と入射光学系４３と光偏向素子（電気光学素子）４４と出射光学系４５と駆動装置４６とを備えている。光源４２は安価でロバスト性の高い半導体レーザーからなるのが好ましい。入射光学系４３は光偏向素子１が導波路型の場合は光利用効率が高く結合させるために、導波路と入射レンズのＮＡを一致させるのが好ましい。出射光学系４５は出射光をコリメートするためのレンズと、必要に応じて、偏向角を拡大するための凸凹レンズを用いるのが好ましい。駆動装置４６は、光源４２及び光偏向素子１を駆動させるための駆動回路、電源、信号発生器等からなり、光偏向装置４１の解像点数と駆動周波数、光出射パワーを決定する。 Next, a deflection device 41 using the optical deflection element 1 will be described.
FIG. 7 is a schematic configuration diagram illustrating an example of the light deflecting device 41. The optical deflection device 41 includes a light source 42, an incident optical system 43, an optical deflection element (electro-optical element) 44, an emission optical system 45, and a driving device 46. The light source 42 is preferably made of an inexpensive and highly robust semiconductor laser. When the optical deflecting element 1 is of a waveguide type, the incident optical system 43 preferably has the same NA between the waveguide and the incident lens in order to couple light with high efficiency. The exit optical system 45 preferably uses a lens for collimating the exit light and, if necessary, a convex / concave lens for enlarging the deflection angle. The drive device 46 includes a drive circuit for driving the light source 42 and the light deflection element 1, a power source, a signal generator, and the like, and determines the number of resolution points, drive frequency, and light emission power of the light deflection device 41.

本実施形態の光偏向装置４１は、電気光学効果を用いた光偏向素子を用いることで、ポリゴンミラーなどのミラーを用いて機械的に光を偏向する光偏向素子を用いた場合に比べて、装置の小型化を容易に実現することができる。また、電極に印加する電圧を高めるだけで、大きな偏向角度を得ることができ、音響光学効果を用いた光偏向素子を用いた場合に比べて、簡単な構成で大きな偏向角度を得ることができる。また、電気光学効果を用いた光偏向素子を用いることで、ＧＨｚオーダーの極めて高速な光スキャンを行うことができる。   The light deflecting device 41 of the present embodiment uses a light deflecting element that uses an electro-optic effect, so that compared to a case where a light deflecting element that mechanically deflects light using a mirror such as a polygon mirror is used. Miniaturization of the apparatus can be easily realized. In addition, it is possible to obtain a large deflection angle simply by increasing the voltage applied to the electrode, and it is possible to obtain a large deflection angle with a simple configuration as compared with the case of using an optical deflection element using an acoustooptic effect. . Further, by using an optical deflection element using an electro-optic effect, extremely high-speed optical scanning on the order of GHz can be performed.

図７に示す偏向装置４１は、例えば、レーザー走査顕微鏡、バーコードリーダーなどのスキャナー部に用いることができる。また、画像形成装置の感光体表面に光を走査して、感光体表面に潜像を書き込む書込装置の光走査部に用いることもできる。   The deflection device 41 shown in FIG. 7 can be used for a scanner unit such as a laser scanning microscope or a barcode reader. Further, it can also be used in an optical scanning unit of a writing apparatus that scans light on the surface of a photoconductor of an image forming apparatus and writes a latent image on the surface of the photoconductor.

以上に説明したものは一例であり、本発明は、次の（１）〜（７）態様毎に特有の効果を奏する。
（１）
光源４２の光が通過するときに光を偏向する光偏向領域Ａに分極反転部２ａと非分極反転部２ｂとが光進行方向に交互に形成された光学結晶２を有する光偏向素子１において、上記光学結晶２の非光偏向領域Ｂにも、分極反転部２ａを形成した。
かかる構成とすることで、実施形態で説明したように、非偏向領域Ｂの伸張または収縮を抑制することができ、非偏向領域Ｂの伸縮の影響で、偏向領域Ａの非分極反転部２ｂと分極反転部２ａとの境界に生じる歪みを低減することができる。これにより、フォトリフラクション現象を抑制することができ、出射光のビーム歪みを抑制することができる。 What was demonstrated above is an example, and this invention has an effect peculiar for every following (1)-(7) aspect.
(1)
In the optical deflection element 1 having the optical crystal 2 in which the polarization inversion portions 2a and the non-polarization inversion portions 2b are alternately formed in the light traveling direction in the light deflection region A that deflects light when the light from the light source 42 passes, Also in the non-light deflection region B of the optical crystal 2, the polarization inversion portion 2a was formed.
With this configuration, as described in the embodiment, the expansion or contraction of the non-deflection region B can be suppressed, and the non-polarization inversion unit 2b of the deflection region A Distortion occurring at the boundary with the polarization inversion portion 2a can be reduced. Thereby, the photorefractive phenomenon can be suppressed and the beam distortion of the emitted light can be suppressed.

（２）
また、上記（１）に記載の態様の光偏向素子１において、非光偏向領域Ｂに、分極反転部２ａと非分極反転部２ｂとを交互に形成した。
かかる構成を備えることで、先の図３を用いて説明したように、非偏向領域Ｂの伸縮を良好に抑制することができる。これにより、偏向領域Ａの非分極反転部２ｂと分極反転部２ａとの境界に生じる歪みを低減することができ、フォトリフラクション現象を抑制することができ、出射光のビーム歪みを抑制することができる。 (2)
Further, in the optical deflection element 1 according to the aspect described in (1) above, the polarization inversion portions 2a and the non-polarization inversion portions 2b are alternately formed in the non-light deflection region B.
By providing such a configuration, expansion and contraction of the non-deflection region B can be satisfactorily suppressed as described with reference to FIG. As a result, distortion generated at the boundary between the non-polarization inverting part 2b and the polarization inverting part 2a in the deflection region A can be reduced, the photorefractive phenomenon can be suppressed, and the beam distortion of the emitted light can be suppressed. it can.

（３）
また、上記（２）に記載の態様の光偏向素子１において、上記非光偏向領域Ｂの分極反転部２ａと非分極反転部２ｂとで形成されるパターン形状を、上記光偏向領域の分極反転部２ａと非分極反転部２ｂとで形成されるパターン形状と同じ形状にした。
かかる構成とすることで、実施形態で説明したように、非偏向領域Ｂの伸縮を抑制することができる。これにより、偏向領域Ａの非分極反転部２ｂと分極反転部２ａとの境界に生じる歪みを低減することができ、フォトリフラクション現象を抑制することができ、出射光のビーム歪みを抑制することができる。 (3)
Further, in the optical deflection element 1 of the aspect described in (2) above, the pattern shape formed by the polarization inversion portion 2a and the non-polarization inversion portion 2b of the non-light deflection region B is the polarization inversion of the light deflection region. It was made into the same shape as the pattern shape formed by the part 2a and the non-polarized inversion part 2b.
By adopting such a configuration, expansion and contraction of the non-deflection region B can be suppressed as described in the embodiment. As a result, distortion generated at the boundary between the non-polarization inverting part 2b and the polarization inverting part 2a in the deflection region A can be reduced, the photorefractive phenomenon can be suppressed, and the beam distortion of the emitted light can be suppressed. it can.

（４）
また、上記（２）に記載の態様の光偏向素子１において、上記非光偏向領域Ｂに、上記光偏向領域Ａの光通過方向に対して平行の延びる分極反転部２ａと非分極反転部２ｂとを交互に形成した。
かかる構成とすることで、変形例１で説明したように、分極反転部２ａの間隔を狭めることができ、実施形態に比べて、非偏向領域Ｂの伸縮を抑制することができる。これにより、偏向領域Ａの非分極反転部２ｂと分極反転部２ａとの境界に生じる歪みをより一層、低減することができる。その結果、フォトリフラクション現象をより一層抑制することができ、出射光のビーム歪みをより一層抑制することができる。 (4)
Further, in the optical deflection element 1 according to the aspect described in (2) above, the polarization inversion portion 2a and the non-polarization inversion portion 2b extending in parallel to the light passing direction of the light deflection region A in the non-light deflection region B. And were formed alternately.
By adopting such a configuration, as described in the first modification, the interval between the polarization inversion portions 2a can be narrowed, and expansion / contraction of the non-deflection region B can be suppressed as compared with the embodiment. Thereby, the distortion which arises in the boundary of the non-polarization inversion part 2b and the polarization inversion part 2a of the deflection | deviation area | region A can be reduced further. As a result, the photorefractive phenomenon can be further suppressed, and the beam distortion of the emitted light can be further suppressed.

（５）
また、上記（２）に記載の態様の光偏向素子１において、上記非光偏向領域Ｂに、上記光偏向領域Ａの光通過方向に対して垂直な分極反転部２ａと非分極反転部２ｂとを交互に形成した。
かかる構成とすることで、変形例２で説明したように、変形例１の構成に比べて、分極反転部２ａの長さを短くすることができ、狭い間隔で分極反転部２ａを形成しても、均一な分極反転部２ａを形成することができる。これにより、製作精度を確保しながら比較的容易な方法で狭い間隔で分極反転部２ａを形成することができる。 (5)
In the optical deflection element 1 according to the aspect described in (2) above, the non-polarization region B includes a polarization inversion unit 2a and a non-polarization inversion unit 2b perpendicular to the light passing direction of the light deflection region A. Were formed alternately.
By adopting such a configuration, as described in the second modification, the length of the polarization inversion unit 2a can be shortened compared to the configuration of the first modification, and the polarization inversion unit 2a is formed at a narrow interval. In addition, a uniform polarization inversion portion 2a can be formed. Thereby, the polarization inversion part 2a can be formed at a narrow interval by a relatively easy method while ensuring manufacturing accuracy.

（６）
また、上記（１）乃至（５）いずれかに記載の態様の光偏向素子１において、上記光学結晶２を、支持基板６上に形成した。
かかる構成とすることで、図４を用いて説明したように、光学結晶の厚みを薄くすることができ、低い駆動電圧で大きな偏角角度を得ることができる。これにより、圧電効果による光学結晶２の伸縮を抑制することができ、偏向領域Ａの非分極反転部２ｂと分極反転部２ａとの境界に生じる歪みをより一層、低減することができる。その結果、フォトリフラクション現象をより一層抑制することができ、出射光のビーム歪みをより一層抑制することができる。また、消費電力を抑えることもできる。 (6)
In the optical deflection element 1 according to any one of the above (1) to (5), the optical crystal 2 was formed on a support substrate 6.
With such a configuration, as described with reference to FIG. 4, the thickness of the optical crystal can be reduced, and a large deflection angle can be obtained with a low driving voltage. Thereby, expansion and contraction of the optical crystal 2 due to the piezoelectric effect can be suppressed, and distortion generated at the boundary between the non-polarization inversion portion 2b and the polarization inversion portion 2a of the deflection region A can be further reduced. As a result, the photorefractive phenomenon can be further suppressed, and the beam distortion of the emitted light can be further suppressed. In addition, power consumption can be suppressed.

（７）
また、光源４２から出射された光を偏向する電気光学効果を有する光学結晶からなる光偏向素子１と、上記光偏向素子１に電圧を印加する電圧印加手段とを備えた光偏向装置４１において、上記光偏向素子として、上記（１）乃至（６）いずれかに記載の態様の光偏向素子を用いた。
かかる構成を備えることで、ビームスポット形状の歪みを抑制することができる。 (7)
Further, in an optical deflecting device 41 including an optical deflecting element 1 made of an optical crystal having an electro-optic effect for deflecting light emitted from a light source 42, and voltage applying means for applying a voltage to the optical deflecting element 1. As the light deflection element, the light deflection element according to any one of the above (1) to (6) was used.
With such a configuration, distortion of the beam spot shape can be suppressed.

１，１Ａ，１Ｂ：光偏向素子
２：光学結晶
２ａ：分極反転部
２ｂ：非分極反転部
３：電極
４：バッファ層
５：接着剤
６：支持基板
１０：電源
４１：光偏向装置
４２：光源
４３：入射光学系
４５：出射光学系
４６：駆動装置
Ａ：光偏向領域
Ｂ：非光偏向領域 1, 1A, 1B: Optical deflection element 2: Optical crystal 2a: Polarization inversion unit 2b: Non-polarization inversion unit 3: Electrode 4: Buffer layer 5: Adhesive 6: Support substrate 10: Power supply 41: Optical deflection device 42: Light source 43: incident optical system 45: emission optical system 46: driving device A: light deflection area B: non-light deflection area

特開平１０−２８８７９８号公報Japanese Patent Laid-Open No. 10-288798

Claims (7)

光源の光が通過するときに光を偏向する光偏向領域に分極反転部と非分極反転部とが光進行方向に交互に形成された光学結晶を有する光偏向素子において、
上記光学結晶の非光偏向領域の所定の箇所に、分極反転部を形成したことを特徴とする光偏向素子。 In an optical deflection element having an optical crystal in which a polarization inversion portion and a non-polarization inversion portion are alternately formed in a light traveling direction in an optical deflection region that deflects light when light from a light source passes through,
An optical deflection element characterized in that a polarization inversion portion is formed at a predetermined location in the non-optical deflection area of the optical crystal. 請求項１の光偏向素子において、
上記非光偏向領域に、分極反転部と非分極反転部とを交互に形成したことを特徴とする光偏向素子。 The light deflection element according to claim 1.
An optical deflection element, wherein a polarization inversion portion and a non-polarization inversion portion are alternately formed in the non-light deflection region. 請求項２の光偏向素子において、
上記非光偏向領域の分極反転部と非分極反転部とで形成されるパターン形状を、上記光偏向領域の分極反転部と非分極反転部とで形成されるパターン形状と同じ形状にしたことを特徴とする光偏向素子。 The optical deflection element according to claim 2,
The pattern shape formed by the polarization inversion portion and the non-polarization inversion portion of the non-light deflection region is the same as the pattern shape formed by the polarization inversion portion and the non-polarization inversion portion of the light deflection region. An optical deflecting element characterized. 請求項２の光偏向素子において、
上記非光偏向領域に、上記光偏向領域の光通過方向に対して平行の延びる分極反転部と非分極反転部とを交互に形成したことを特徴とする光偏向素子。 The optical deflection element according to claim 2,
An optical deflection element, wherein polarization inversion portions and non-polarization inversion portions extending in parallel with the light passing direction of the light deflection region are alternately formed in the non-light deflection region. 請求項２の光偏向素子において、
上記非光偏向領域に、上記光偏向領域の光通過方向に対して垂直な分極反転部と非分極反転部とを交互に形成したことを特徴とする光偏向素子。 The optical deflection element according to claim 2,
An optical deflection element, wherein a polarization inversion portion and a non-polarization inversion portion perpendicular to the light passing direction of the light deflection region are alternately formed in the non-light deflection region. 請求項１乃至５いずれかの光偏向素子において、
上記光学結晶を、支持基板上に形成したことを特徴とする光偏向素子。 The light deflection element according to any one of claims 1 to 5,
An optical deflection element, wherein the optical crystal is formed on a support substrate. 光源から出射された光を偏向する電気光学効果を有する光学結晶からなる光偏向素子と、
上記光偏向素子に電圧を印加する電圧印加手段とを備えた光偏向装置において、
上記光偏向素子として、請求項１乃至６いずれかの光偏向素子を用いたことを特徴とする光偏向装置。 A light deflecting element made of an optical crystal having an electro-optic effect for deflecting light emitted from a light source;
In an optical deflecting device comprising voltage applying means for applying a voltage to the optical deflecting element,
An optical deflecting device using the optical deflecting element according to claim 1 as the optical deflecting element.
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CN113640915A (en) * 2021-08-20 2021-11-12 南京南智先进光电集成技术研究院有限公司 Small-period Z-cut piezoelectric wafer, thin film, waveguide and preparation method thereof

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JPH0351826A (en) * 1989-07-20 1991-03-06 Nec Corp Optical control device
JPH09146128A (en) * 1995-11-24 1997-06-06 Sony Corp Electrooptic element
JP2004118049A (en) * 2002-09-27 2004-04-15 Sharp Corp Optical path converting device
JP2004294709A (en) * 2003-03-26 2004-10-21 Sumitomo Osaka Cement Co Ltd Optical waveguide element
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CN113640915A (en) * 2021-08-20 2021-11-12 南京南智先进光电集成技术研究院有限公司 Small-period Z-cut piezoelectric wafer, thin film, waveguide and preparation method thereof
CN113640915B (en) * 2021-08-20 2023-11-14 南京南智先进光电集成技术研究院有限公司 Small-period Z-cut piezoelectric wafer, thin film, waveguide and preparation method thereof

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