JP4197799B2 - Diffraction grating type polarization element - Google Patents

Diffraction grating type polarization element Download PDF

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JP4197799B2
JP4197799B2 JP15484099A JP15484099A JP4197799B2 JP 4197799 B2 JP4197799 B2 JP 4197799B2 JP 15484099 A JP15484099 A JP 15484099A JP 15484099 A JP15484099 A JP 15484099A JP 4197799 B2 JP4197799 B2 JP 4197799B2
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dielectric film
birefringent
isotropic
polarizing element
intermediate layer
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JP2000347028A (en
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喜彦 飯島
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Ricoh Co Ltd
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Ricoh Co Ltd
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Description

【０００１】
【発明の属する技術分野】
この発明は、各種光学装置に使用される回折格子型偏光素子に関するものである。
【０００２】
【従来の技術】
光の回折を利用した偏光素子としては、例えば特開昭６３−５５５０１号公報に示されているようにＬｉＮｂ０3 にプロトン交換を利用して製造された回折格子型偏光素子が使用されている。この偏光素子は薄型で量産性を有するが、ＬｉＮｂ０3 と高価な単結晶基板を用いる必要があった。これに対して例えば特開平５−２８９０２７号公報に示された偏光素子は基板上に格子状の複屈折性誘電体膜を斜め蒸着法により形成し、この複屈折性誘電体膜の格子の溝内に等方性を有する誘電体材料をスパッタ法や蒸着法あるいは塗布法により充填して等方性誘電体膜を形成し、複屈折性誘電体膜と等方性誘電体膜とを同一基板上に交互に備えた回折格子構造としている。
【０００３】
【発明が解決しようとする課題】
特開平５−２８９０２７号公報に示された偏光素子は高価な単結晶基板を用いる必要はないが、基板上に格子状の複屈折性誘電体膜を形成後、複屈折性誘電体膜の格子の溝内に等方性を有する誘電体材料を充填して等方性誘電体膜を形成するときに、複屈折性誘電体膜と等方性誘電体膜の界面に空隙や欠陥が生じ易く、格子の間隙を良好な状態で形成することが極めて困難であった。また、複屈折性誘電体膜と等方性誘電体膜の構造や組成の違いから複屈折性誘電体膜と等方性誘電体膜の界面に残留応力やひずみが生じ、その結果、形成した等方性誘電体膜が剥離するという現象も生じていた。さらに、等方性誘電体膜として樹脂等を液相系を用いて塗布し、それを固化して形成する場合には、基板と複屈折性誘電体膜に対する樹脂との濡れ性を良好にするのが困難であり、濡れ性を良好にできた場合でも、その屈折率が所望の値に調整できない等の問題があった。
【０００４】
この発明はかかる問題を解消し、複屈折性誘電体材料にオーバーコート材料である誘電体材料を充填する際に生じる残留応力やひずみを緩和し、充填した誘電体材料の剥離をも防止できる回折格子型偏光素子を提供することを目的とするものである。
【０００５】
【課題を解決するための手段】
この発明に係る回折格子型偏光素子は、基板上の同一面上に交互に設けた二種類の誘電体領域で回折格子構造をなし、少なくとも一方の領域が複屈折性を有する誘電体材料で形成された回折格子型偏光素子において、基板上に設けた複屈折性を有する誘電体材料と他方の誘電体材料との界面に、複屈折性を有する誘電体材料の構成元素から他方の誘電体材料の構成元素まで連続的に組成を変化させて形成した中間層を少なくとも一層挿入したことを特徴とする。
【０００９】
上記複屈折性を有する誘電体材料は高分子材料を使用する。
【００１１】
【発明の実施の形態】
この発明の偏光素子はガラス等光学的に等方性を有する基板と、基板上に格子状に設けられた複屈折性誘電体膜と、複屈折性誘電体膜の側面界面に設けられた中間層及び中間層を挟んだ間の格子状の複屈折性誘電体膜の溝に設けられた等方性誘電体膜を有する。複屈折性誘電体膜を構成する複屈折を有する誘電体材料は例えばＴａ，Ｗ，Ｂｉ，Ｔｉ，Ｓｎ等の金属酸化物からなる。中間層は複屈折性誘電体膜と等方性誘電体膜とは組成あるいは構造が異なっている組成物で形成されている。
【００１２】
このように複屈折性誘電体膜と等方性誘電体膜との界面に、複屈折性誘電体膜と等方性誘電体膜とは組成あるいは構造が異なる中間層を形成することにより、等方性誘電体膜を形成するときに、複屈折性誘電体膜と等方性誘電体膜との界面に空隙や欠陥等が生じることを防ぐとともに複屈折性誘電体膜と等方性誘電体膜の構造や組成の違いから生じる残留応力やひずみの影響を緩和して、形成した等方性誘電体膜が剥離することを防止する。
【００１３】
【実施例】
図１はこの発明の一実施例の回折格子型偏光素子の構成を示す断面図である。図に示す用に、偏光素子１はガラス等光学的に等方性を有する基板２と、基板２上に格子状に設けられた複屈折性誘電体膜３と複屈折性誘電体膜３の側面界面に設けられた中間層４及び中間層４を挟んだ間の格子状の複屈折性誘電体膜３の溝に設けられた等方性誘電体膜５を有する。
【００１４】
複屈折性誘電体膜３を構成する複屈折を有する誘電体材料は有機物，無機物を問わず複屈折性を有するもので有れば良いが、安定性と量産性を考慮すると金属酸化物あるいは高分子材料が好ましい。金属酸化物としては、例えばＴａ，Ｗ，Ｂｉ，Ｔｉ，Ｓｎ等の酸化物を用いることができるが、特にこれらに限定されるものではなく、複屈折性を有するものであれば良く、複数の金属の酸化物（化合物）であっても良い。このような金属酸化物を用い斜め蒸着法により複屈折性誘電体膜３を形成することにより複屈折性を付与することができる。また、高分子材料としては、特にその分子量が限定されるわけでなく、複屈折性を有していれば良い。もちろん、延伸やラビング等を用いて複屈折性を付与した材料を使用しても良い。中間層４は複屈折性誘電体膜３と等方性誘電体膜５とは組成あるいは構造が異なっている組成物又は複数の組成物の混合物あるいは複屈折性誘電体膜３と等方性誘電体膜５と組成及び構造の両方が異なっている組成物又は複数の組成物の混合物により形成される。
【００１５】
上記のように構成された偏光素子１を作製する方法を図２の処理工程図を参照して説明する。
【００１６】
まず、図２（ａ）に示すように、一定厚さの基板２上に例えば金属酸化物を斜め蒸着法を用いて積層して一定膜厚の複屈折性誘電体膜３を形成する。その後、形成した複屈折性誘電体膜３の表面にフォトリゾグラフィー技術等を用いて格子状のマスクを積層し、エッチング等により複屈折性誘電体膜３を、図２（ｂ）に示すように、格子状に加工する。この格子状に加工された複屈折性誘電体膜３の側面に、図２（ｃ）に示すように、中間層４を形成し、中間層４を両側に有する複屈折性誘電体膜３の溝内に等方性を有する誘電体材料をスパッタ法や蒸着法あるいは塗布法により充填して、図２（ｄ）に示すように、等方性誘電体膜５を形成して偏光素子１を作製する。
【００１７】
このように複屈折性誘電体膜３と等方性誘電体膜５との界面に、複屈折性誘電体膜３と等方性誘電体膜５とは組成あるいは構造が異なる中間層４を形成することにより、等方性誘電体膜５を形成するとき、複屈折性誘電体膜３と等方性誘電体膜５との界面に空隙や欠陥等が生じることを防ぐことができるとともに複屈折性誘電体膜３と等方性誘電体膜５の構造や組成の違いから生じる残留応力やひずみの影響を緩和して、形成した等方性誘電体膜５が剥離することを防止できる。したがって、複屈折性誘電体膜３の格子の間隙を良好な状態で形成することができる。
【００１８】
この複屈折性誘電体膜３と等方性誘電体膜５との界面を形成する中間層４に複屈折性誘電体膜３と等方性誘電体膜５のどちらか一方の構成元素を一種類以上含有したり、複屈折性誘電体膜３と等方性誘電体膜５の両方の構成元素を一種類以上ずつ含有する場合、中間層４としての機能をより有効に発揮することができ、高特性の偏光素子を形成することができる。また、中間層４を複屈折性誘電体膜３側から複屈折性誘電体膜３を形成する誘電体材料から等方性誘電体膜５を形成する誘電体材料に連続的に組成を変化させると、中間層４としてさらに高い機能を発揮することができ、より高特性の偏光素子を形成することができる。
【００１９】
また、偏光素子１を作製する場合に、複屈折性誘電体膜３の常光線と異常光線に対する屈折率と膜厚及び等方性誘電体膜５の屈折率を適切に調整する必要がある。そこで中間層４の屈折率を複屈折性誘電体膜３の常光線の屈折率あるいは異常光線の屈折率のいずれかに等しくすることにより、偏光素子１としての特性を向上することができる。なお、基板２と複屈折性誘電体膜３と等方性誘電体膜５にどのような材料を選択するかによっても異なるが、中間層４を複屈折性誘電体膜３と等方性誘電体膜５の界面ばかりでなく、基板２と両方の誘電体膜３，５の界面に設けた方が効果が得られる場合もある。
【００２０】
上記実施例は等方性誘電体膜５を複屈折性誘電体膜３の格子の溝にだけ設けた場合について説明したが、図３の断面図に示す偏光素子１ａのように、複屈折性誘電体膜３の上面と側面及び複屈折性誘電体膜３の格子の溝の基板２の上面を中間層４で被覆し、この中間層４の上に等方性誘電体膜５を形成し、複屈折性誘電体膜３と基板２を等方性誘電体膜５で覆うようにしても良い。
【００２１】
また、上記各実施例は複屈折性誘電体膜３を格子状に形成して、複屈折性誘電体膜３の格子間の溝の深さを複屈折性誘電体膜３の膜厚と同じにしたっ場合について説明したが、図４の断面図に示す偏光素子１ｂのように、複屈折性誘電体膜３に一定深さの凹溝を設けて格子を形成し、この複屈折性誘電体膜３の下面全体が基板２の上面を覆うようにしても良い。
【００２２】
〔具体例〕 例えば厚さ１ｍｍのガラス基板（コーニング7059）２上に複屈折性を有するＴa2Ｏ5を斜め蒸着法を用いて厚さ５μｍの複屈折性誘電体膜３を積層した。この複屈折性誘電体膜３の表面にフォトリソグラフィー技術等を用いて格子状のマスクを積層し、エッチングによりＴａ2Ｏ5の複屈折性誘電体膜３を格子状に加工した。この格子状の複屈折性誘電体膜３にＴａ2Ｏ3を被覆して中間層４を形成した後、アクリル系樹脂をスピンコート法を用いて塗布し、さらに紫外線照射によって樹脂を硬化させて複屈折性誘電体膜３の格子の溝を充填して等方性誘電体膜５を形成して、図３に示す偏光素子１ａを試料Ａとして作製した。この偏光素子１ａの試料Ａの断面を電子顕微鏡により観察したところ空隙等はなかった。また、偏光素子としての特性も良好であった。
【００２３】
〔具体例２〕 厚さ１ｍｍのガラス基板２上に複屈折性を有するＴa2Ｏ5を斜め蒸着法を用いて厚さ１０μｍの複屈折性誘電体膜３を積層した。この複屈折性誘電体膜３の表面にフォトリソグラフィー技術等を用いて格子状のマスクを積層し、エッチングにより図４に示すように複屈折性誘電体膜３に凹溝を加工して格子状にした。この複屈折性誘電体膜３の表面にＴａ2Ｏ5−ＴａＣ−Ｔａ2 Ｃ組成物で中間層４を形成した後、アクリル系樹脂で等方性誘電体膜５を形成して、図４に示す偏光素子１ｂを試料Ｂとして作製した。この偏光素子１の断面を電子顕微鏡により観察したところ空隙等は生じていなかった。比較例として中間層４を含まない試料Ｃを作製した。中間層４を含まない試料Ｃの断面を電子顕微鏡により観察したところ複屈折性誘電体膜３と等方性誘電体膜５の界面に空隙等が観察された。さらに、偏光素子としての特性は中間層４を有する偏光素子１ｂの試料Ｂ方が比較例の試料Ｃより良好であった。
【００２４】
〔具体例３〕 具体例２と全く同じ構成で中間層４だけをＴａ2Ｏ5−（Ｃ5Ｈ5）2ＴａＨ3−Ｔａ（ＯＣ2Ｈ5）5−Ｃ組成物に換えて図４に示す偏光素子１ｂを試料Ｄとして作製した。この偏光素子１ｂの試料Ｄの断面を電子顕微鏡により観察したところ空隙等は生じていなかく、偏光素子としての特性も中間層４を含まない試料Ｃと比べて良好であった。また、作製した偏光素子１ｂの試料Ｄと比較例の試料Ｃを恒温槽に入れ、温度を−２０℃〜＋５０℃で繰り返し変化させた。その結果、中間層を含まない試料Ｃは等方性誘電体膜５の一部が剥離したが、偏光素子１ｂの試料Ｄにおいては等方性誘電体膜５の剥離は確認されなかった。
【００２５】
〔具体例４〕 厚さ１ｍｍのガラス基板２上に複屈折性を有するポリイミド系樹脂の延伸材を膜厚10μｍで接着して複屈折性誘電体膜３を形成した。この複屈折性誘電体膜３にフォトリソグラフィー技術等を用いて格子状のマスクを積層して、エッチングにより複屈折性誘電体膜３を凹溝を有する格子状に加工した。この複屈折性誘電体膜３の表面にポリイミド系樹脂とアクリル系樹脂の混合物を、ポリイミド系樹脂側からアクリル系樹脂側まで連続的に組成を変化させて被覆して中間層４を形成した後、中間層４の表面にアクリル系樹脂をスピンコート法を用いて塗布して紫外線照射によってアクリル系樹脂を硬化させて等方性誘電体膜５を形成して、図４に示す偏光素子１ｂを試料Ｅとして作製した。この偏光素子１ｂの試料Ｅの断面を電子顕微鏡により観察した結果、空隙等は生じていなかった。また、比較例である中間層４を有しない試料Ｃと共に偏光素子としての特性を測定したところ、偏光素子１ｂの試料Ｅの方が良好であった。また、試料Ｅと比較例の試料Ｃを恒温槽に入れ、温度を−２０℃〜＋５０℃で繰り返し変化させ結果、中間層を含まない試料Ｃは等方性誘電体膜５の一部が剥離したが、偏光素子１ｂの試料Ｅにおいては等方性誘電体膜５の剥離は確認されなかった。
【００２６】
【発明の効果】
この発明は以上説明したように、基板上に設けた複屈折性を有する誘電体材料と他方の誘電体材料との界面に、複屈折性を有する誘電体材料の構成元素から他方の誘電体材料の構成元素まで連続的に組成を変化させて形成した中間層を少なくとも一層挿入することにより、両誘電体材料の界面に空隙や欠陥等が生じることを防ぐことができる。また、両誘電体材料の構造や組成の違いから生じる残留応力やひずみの影響を緩和して、形成した誘電体膜が剥離することを防止できる。したがって、特性の良好な偏光素子を得ることができる。
【００２８】
また、複屈折性を有する誘電体材料として高分子材料を使用して適切に選択することにより、空隙や欠陥が生じにくくできると共に誘電体の剥離等も生じない、優れた特性を有する偏光素子を得ることができる。
【図面の簡単な説明】
【図１】この発明の実施例の回折格子型偏光素子の構成を示す断面図である。
【図２】上記実施例の偏光素子を作製するときの処理工程図であ。
【図３】第２の実施例の構成を示す断面図である。
【図４】第３の実施例の構成を示す断面図である。
【符号の説明】
１；偏光素子、２；基板、３；複屈折性誘電体膜、４；中間層、
５；等方性誘電体膜。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a diffraction grating type polarizing element used in various optical devices.
[0002]
[Prior art]
The polarizing element utilizing light diffraction, the diffraction grating type polarizing element is used which is prepared by using a proton exchange LiNbO 3 as shown in JP-Sho 63-55501. This polarizing element has a mass production thin, it is necessary to use an expensive single crystal substrate and LiNbO 3. On the other hand, for example, in the polarizing element disclosed in Japanese Patent Application Laid-Open No. 5-289027, a grating-like birefringent dielectric film is formed on a substrate by an oblique deposition method, and the grating grooves of the birefringent dielectric film are formed. An isotropic dielectric film is formed by filling an isotropic dielectric material in the inside by sputtering, vapor deposition or coating, and the birefringent dielectric film and the isotropic dielectric film are formed on the same substrate. The diffraction grating structure is provided alternately above.
[0003]
[Problems to be solved by the invention]
The polarizing element disclosed in JP-A-5-289027 does not need to use an expensive single crystal substrate, but after forming a lattice-like birefringent dielectric film on the substrate, the lattice of the birefringent dielectric film is formed. When forming an isotropic dielectric film by filling the groove with isotropic dielectric material, voids and defects are likely to occur at the interface between the birefringent dielectric film and the isotropic dielectric film. It was extremely difficult to form the lattice gap in a good state. Also, due to the difference in structure and composition between the birefringent dielectric film and the isotropic dielectric film, residual stress and strain occur at the interface between the birefringent dielectric film and the isotropic dielectric film, resulting in the formation. There was also a phenomenon that the isotropic dielectric film peeled off. Further, when the resin is applied as an isotropic dielectric film using a liquid phase system and solidified, the wettability between the substrate and the resin with respect to the birefringent dielectric film is improved. However, even when the wettability can be improved, there is a problem that the refractive index cannot be adjusted to a desired value.
[0004]
This invention eliminates such problems, relaxes residual stress and strain generated when filling a birefringent dielectric material with a dielectric material, which is an overcoat material, and prevents diffraction of the filled dielectric material. An object of the present invention is to provide a grating-type polarizing element.
[0005]
[Means for Solving the Problems]
The diffraction grating type polarizing element according to the present invention has a diffraction grating structure composed of two types of dielectric regions alternately provided on the same surface on the substrate, and at least one region is formed of a dielectric material having birefringence. In the diffraction grating type polarizing element, the other dielectric material is formed on the interface between the birefringent dielectric material provided on the substrate and the other dielectric material from the constituent element of the birefringent dielectric material. At least one intermediate layer formed by continuously changing the composition up to the constituent elements is inserted.
[0009]
A polymer material is used as the dielectric material having birefringence .
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The polarizing element of the present invention includes an optically isotropic substrate such as glass, a birefringent dielectric film provided in a lattice shape on the substrate, and an intermediate provided at a side interface of the birefringent dielectric film. An isotropic dielectric film provided in the groove of the lattice-like birefringent dielectric film between the layer and the intermediate layer. The dielectric material having birefringence constituting the birefringent dielectric film is made of a metal oxide such as Ta, W, Bi, Ti, or Sn. The intermediate layer is formed of a composition having a different composition or structure between the birefringent dielectric film and the isotropic dielectric film.
[0012]
Thus, by forming an intermediate layer having a different composition or structure between the birefringent dielectric film and the isotropic dielectric film at the interface between the birefringent dielectric film and the isotropic dielectric film, etc. When forming an isotropic dielectric film, a void or a defect is prevented from being generated at the interface between the birefringent dielectric film and the isotropic dielectric film, and the birefringent dielectric film and the isotropic dielectric are formed. The effect of residual stress and strain resulting from the difference in film structure and composition is alleviated to prevent the formed isotropic dielectric film from peeling off.
[0013]
【Example】
FIG. 1 is a sectional view showing the structure of a diffraction grating type polarizing element according to one embodiment of the present invention. As shown in the figure, the polarizing element 1 includes an optically isotropic substrate 2 such as glass, a birefringent dielectric film 3 and a birefringent dielectric film 3 provided in a lattice shape on the substrate 2. An intermediate layer 4 provided at the side interface and an isotropic dielectric film 5 provided in a groove of the lattice-like birefringent dielectric film 3 between the intermediate layers 4 are provided.
[0014]
The birefringent dielectric material 3 constituting the birefringent dielectric film 3 may be birefringent regardless of whether it is organic or inorganic. However, in view of stability and mass productivity, metal oxide or high Molecular materials are preferred. As the metal oxide, for example, oxides such as Ta, W, Bi, Ti, and Sn can be used. However, the metal oxide is not particularly limited, and any metal oxide having birefringence may be used. It may be a metal oxide (compound). Birefringence can be imparted by forming the birefringent dielectric film 3 using such a metal oxide by an oblique deposition method. Further, the molecular weight of the polymer material is not particularly limited, and it may be birefringent. Of course, a material imparted with birefringence by stretching or rubbing may be used. The intermediate layer 4 is composed of a composition having a different composition or structure from the birefringent dielectric film 3 and the isotropic dielectric film 5, a mixture of a plurality of compositions, or the birefringent dielectric film 3 and the isotropic dielectric. The body film 5 is formed of a composition having a composition and a structure different from each other or a mixture of a plurality of compositions.
[0015]
A method of manufacturing the polarizing element 1 configured as described above will be described with reference to the processing step diagram of FIG.
[0016]
First, as shown in FIG. 2A, a birefringent dielectric film 3 having a constant film thickness is formed by laminating, for example, a metal oxide on the substrate 2 having a constant thickness by using an oblique deposition method. Thereafter, a lattice-like mask is laminated on the surface of the formed birefringent dielectric film 3 using a photolithographic technique or the like, and the birefringent dielectric film 3 is formed by etching or the like as shown in FIG. Then, it is processed into a lattice shape. As shown in FIG. 2C, an intermediate layer 4 is formed on the side surface of the birefringent dielectric film 3 processed into a lattice shape, and the birefringent dielectric film 3 having the intermediate layer 4 on both sides is formed. The isotropic dielectric film 5 is formed as shown in FIG. 2D by filling the groove with an isotropic dielectric material by sputtering, vapor deposition or coating, and the polarizing element 1 is formed. Make it.
[0017]
Thus, the intermediate layer 4 having a different composition or structure between the birefringent dielectric film 3 and the isotropic dielectric film 5 is formed at the interface between the birefringent dielectric film 3 and the isotropic dielectric film 5. As a result, when the isotropic dielectric film 5 is formed, it is possible to prevent the formation of voids or defects at the interface between the birefringent dielectric film 3 and the isotropic dielectric film 5, and birefringence. The effect of residual stress and strain resulting from the difference in structure and composition between the isotropic dielectric film 3 and the isotropic dielectric film 5 can be relaxed, and the formed isotropic dielectric film 5 can be prevented from peeling off. Therefore, the lattice gap of the birefringent dielectric film 3 can be formed in a good state.
[0018]
One constituent element of either the birefringent dielectric film 3 or the isotropic dielectric film 5 is added to the intermediate layer 4 that forms the interface between the birefringent dielectric film 3 and the isotropic dielectric film 5. When it contains more than one kind, or contains at least one kind of constituent elements of both the birefringent dielectric film 3 and the isotropic dielectric film 5, the function as the intermediate layer 4 can be more effectively exhibited. High-polarizing elements can be formed. The composition of the intermediate layer 4 is continuously changed from the dielectric material forming the birefringent dielectric film 3 to the dielectric material forming the isotropic dielectric film 5 from the birefringent dielectric film 3 side. As a result, the intermediate layer 4 can exhibit a higher function, and a polarizing element with higher characteristics can be formed.
[0019]
Further, when the polarizing element 1 is manufactured, it is necessary to appropriately adjust the refractive index and film thickness of the birefringent dielectric film 3 with respect to the ordinary ray and extraordinary ray, and the refractive index of the isotropic dielectric film 5. Therefore, by making the refractive index of the intermediate layer 4 equal to either the ordinary ray refractive index or the extraordinary ray refractive index of the birefringent dielectric film 3, the characteristics of the polarizing element 1 can be improved. The intermediate layer 4 and the birefringent dielectric film 3 and the isotropic dielectric are different depending on the material selected for the substrate 2, the birefringent dielectric film 3, and the isotropic dielectric film 5. In some cases, the effect is obtained not only at the interface of the body film 5 but also at the interface between the substrate 2 and both dielectric films 3 and 5.
[0020]
In the above embodiment, the case where the isotropic dielectric film 5 is provided only in the groove of the grating of the birefringent dielectric film 3 has been described. However, like the polarizing element 1a shown in the cross-sectional view of FIG. The upper surface and side surfaces of the dielectric film 3 and the upper surface of the substrate 2 in the lattice grooves of the birefringent dielectric film 3 are covered with an intermediate layer 4, and an isotropic dielectric film 5 is formed on the intermediate layer 4. The birefringent dielectric film 3 and the substrate 2 may be covered with an isotropic dielectric film 5.
[0021]
In each of the above embodiments, the birefringent dielectric film 3 is formed in a lattice shape, and the depth of the groove between the lattices of the birefringent dielectric film 3 is the same as the film thickness of the birefringent dielectric film 3. However, as in the polarizing element 1b shown in the cross-sectional view of FIG. 4, the birefringent dielectric film 3 is provided with a groove having a certain depth to form a grating, and this birefringent dielectric The entire lower surface of the film 3 may cover the upper surface of the substrate 2.
[0022]
Specific Example For example, a birefringent dielectric film 3 having a thickness of 5 μm was laminated on a glass substrate (Corning 7059) 2 having a thickness of 1 mm by using Ta 2 O 5 having birefringence using an oblique deposition method. A lattice-like mask was laminated on the surface of the birefringent dielectric film 3 using a photolithography technique or the like, and the Ta 2 O 5 birefringent dielectric film 3 was processed into a lattice shape by etching. After this lattice-like birefringent dielectric film 3 is coated with Ta 2 O 3 to form the intermediate layer 4, an acrylic resin is applied using a spin coating method, and the resin is cured by ultraviolet irradiation. An isotropic dielectric film 5 was formed by filling the grating grooves of the birefringent dielectric film 3, and the polarizing element 1a shown in FIG. When the cross section of the sample A of the polarizing element 1a was observed with an electron microscope, there were no voids. Moreover, the characteristic as a polarizing element was also favorable.
[0023]
Specific Example 2 A birefringent dielectric film 3 having a thickness of 10 μm was laminated on a glass substrate 2 having a thickness of 1 mm by using Ta 2 O 5 having birefringence using an oblique deposition method. A lattice-like mask is laminated on the surface of the birefringent dielectric film 3 using a photolithography technique or the like, and a groove is formed in the birefringent dielectric film 3 by etching as shown in FIG. I made it. After forming the intermediate layer 4 with a Ta 2 O 5 —TaC—Ta 2 C composition on the surface of the birefringent dielectric film 3, the isotropic dielectric film 5 is formed with an acrylic resin. A polarizing element 1b shown in FIG. When the cross section of this polarizing element 1 was observed with the electron microscope, the space | gap etc. were not produced. As a comparative example, a sample C not including the intermediate layer 4 was produced. When the cross section of the sample C not including the intermediate layer 4 was observed with an electron microscope, voids or the like were observed at the interface between the birefringent dielectric film 3 and the isotropic dielectric film 5. Furthermore, the polarizing element 1b having the intermediate layer 4 was better in the characteristics as the polarizing element than the sample C of the comparative example.
[0024]
[Specific Example 3] With the same configuration as that of Specific Example 2, only the intermediate layer 4 is replaced with a Ta 2 O 5 — (C 5 H 5 ) 2 TaH 3 —Ta (OC 2 H 5 ) 5 —C composition. A polarizing element 1b shown in FIG. When the cross section of the sample D of the polarizing element 1b was observed with an electron microscope, no voids or the like were generated, and the characteristics as the polarizing element were better than those of the sample C not including the intermediate layer 4. Moreover, the sample D of the produced polarizing element 1b and the sample C of the comparative example were put in a thermostat, and the temperature was repeatedly changed at −20 ° C. to + 50 ° C. As a result, part of the isotropic dielectric film 5 peeled off from the sample C not including the intermediate layer, but peeling of the isotropic dielectric film 5 was not confirmed in the sample D of the polarizing element 1b.
[0025]
[Specific Example 4] A birefringent dielectric film 3 was formed by adhering a stretched material of polyimide resin having birefringence on a glass substrate 2 having a thickness of 1 mm so as to have a thickness of 10 μm. A lattice-like mask was laminated on the birefringent dielectric film 3 using a photolithography technique or the like, and the birefringent dielectric film 3 was processed into a lattice shape having a concave groove by etching. After the surface of the birefringent dielectric film 3 is coated with a mixture of a polyimide resin and an acrylic resin by continuously changing the composition from the polyimide resin side to the acrylic resin side to form the intermediate layer 4 Then, an acrylic resin is applied to the surface of the intermediate layer 4 by using a spin coating method, and the acrylic resin is cured by ultraviolet irradiation to form an isotropic dielectric film 5, and the polarizing element 1b shown in FIG. Sample E was prepared. As a result of observing the cross section of the sample E of the polarizing element 1b with an electron microscope, no voids or the like were generated. Moreover, when the characteristic as a polarizing element was measured with the sample C which does not have the intermediate | middle layer 4 which is a comparative example, the sample E of the polarizing element 1b was more favorable. Moreover, the sample E and the sample C of the comparative example are put in a thermostat, and the temperature is repeatedly changed at −20 ° C. to + 50 ° C. As a result, in the sample C not including the intermediate layer, part of the isotropic dielectric film 5 is peeled However, peeling of the isotropic dielectric film 5 was not confirmed in the sample E of the polarizing element 1b.
[0026]
【The invention's effect】
As described above, according to the present invention, a dielectric material having a birefringence provided on a substrate and an interface between the other dielectric material and a dielectric material having the birefringence are used as the other dielectric material. By inserting at least one intermediate layer formed by continuously changing the composition up to the constituent elements, it is possible to prevent voids, defects, and the like from occurring at the interface between the two dielectric materials. In addition, it is possible to reduce the influence of residual stress and strain caused by the difference in structure and composition of both dielectric materials, and prevent the formed dielectric film from peeling off. Therefore, a polarizing element with good characteristics can be obtained.
[0028]
In addition, by appropriately selecting a polymer material as a dielectric material having birefringence, a polarizing element having excellent characteristics that can hardly cause voids and defects and does not cause peeling of the dielectric, etc. Obtainable.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a diffraction grating type polarizing element according to an embodiment of the present invention.
FIG. 2 is a process diagram when manufacturing the polarizing element of the above embodiment.
FIG. 3 is a cross-sectional view showing a configuration of a second embodiment.
FIG. 4 is a cross-sectional view showing a configuration of a third embodiment.
[Explanation of symbols]
1; polarizing element, 2; substrate, 3; birefringent dielectric film, 4; intermediate layer,
5: Isotropic dielectric film.

Claims (2)

基板上の同一面上に交互に設けた二種類の誘電体領域で回折格子構造をなし、少なくとも一方の領域が複屈折性を有する誘電体材料で形成された回折格子型偏光素子において、
基板上に設けた複屈折性を有する誘電体材料と他方の誘電体材料との界面に、複屈折性を有する誘電体材料の構成元素から他方の誘電体材料の構成元素まで連続的に組成を変化させて形成した中間層を少なくとも一層挿入したことを特徴とする回折格子型偏光素子。In a diffraction grating type polarization element in which a diffraction grating structure is formed by two types of dielectric regions alternately provided on the same surface on a substrate, and at least one region is formed of a dielectric material having birefringence.
A composition is continuously formed from the constituent element of the birefringent dielectric material to the constituent element of the other dielectric material at the interface between the dielectric material having birefringence provided on the substrate and the other dielectric material. A diffraction grating type polarizing element , wherein at least one intermediate layer formed by changing is inserted. 上記複屈折性を有する誘電体材料が高分子材料である請求項１記載の回折格子型偏光素子。2. The diffraction grating type polarizing element according to claim 1, wherein the dielectric material having birefringence is a polymer material.
JP15484099A 1999-06-02 1999-06-02 Diffraction grating type polarization element Expired - Fee Related JP4197799B2 (en)

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Publication number Priority date Publication date Assignee Title
CN102923636A (en) * 2012-10-30 2013-02-13 上海丽恒光微电子科技有限公司 Semiconductor structure and manufacturing method thereof

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JP2002169010A (en) * 2000-12-04 2002-06-14 Minolta Co Ltd Diffraction optical element
EP1420275B1 (en) * 2001-08-24 2008-10-08 Asahi Glass Company, Limited Isolator and optical attenuator

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102923636A (en) * 2012-10-30 2013-02-13 上海丽恒光微电子科技有限公司 Semiconductor structure and manufacturing method thereof
CN102923636B (en) * 2012-10-30 2015-11-25 上海丽恒光微电子科技有限公司 Semiconductor structure and preparation method thereof

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