JP2002169010A - Diffraction optical element - Google Patents
Diffraction optical elementInfo
- Publication number
- JP2002169010A JP2002169010A JP2000368614A JP2000368614A JP2002169010A JP 2002169010 A JP2002169010 A JP 2002169010A JP 2000368614 A JP2000368614 A JP 2000368614A JP 2000368614 A JP2000368614 A JP 2000368614A JP 2002169010 A JP2002169010 A JP 2002169010A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- diffraction grating
- optical element
- substrate
- diffraction
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は回折光学素子に関
し、特に、基板とその上に設けられた薄膜を備え、薄膜
に回折格子が形成されている回折光学素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffractive optical element, and more particularly, to a diffractive optical element having a substrate and a thin film provided thereon, wherein a diffraction grating is formed on the thin film.
【０００２】[0002]
【従来の技術】回折格子は、結合器、偏向器、分波器、
反射器、波長フィルタ、モード変換器、光ピックアップ
用レンズ等の種々の受動素子として、また、光波制御用
の機能素子として利用されており、きわめて重要な光学
素子の１つとなっている。近年では、特に回折効率の高
い回折格子が求められており、このため、光の波長程度
あるいはそれ以下のきわめて高度な加工精度が必要にな
っている。2. Description of the Related Art Diffraction gratings include couplers, deflectors, duplexers,
It is used as various passive elements such as a reflector, a wavelength filter, a mode converter, and a lens for an optical pickup, and as a functional element for controlling light waves, and is one of extremely important optical elements. In recent years, a diffraction grating having particularly high diffraction efficiency has been demanded, and for this reason, extremely high processing accuracy of about the wavelength of light or less is required.
【０００３】一般に、回折格子の凹凸の形成にはエッチ
ングが用いられる。従来は、ガラス製の基板の表面をエ
ッチングにより加工して、基板自体に回折格子を作製し
ていたが、最近では、凹凸の高低差が小さい回折格子を
作製するために、基板の表面に薄膜を設けて、薄膜を回
折格子とすることが行われている。In general, etching is used to form unevenness of a diffraction grating. In the past, the surface of a glass substrate was processed by etching to create a diffraction grating on the substrate itself, but recently, in order to produce a diffraction grating with a small difference in elevation, a thin film is formed on the surface of the substrate. Is provided, and the thin film is used as a diffraction grating.
【０００４】薄膜を回折格子とする場合、凹凸の高低差
を薄膜の厚さで規定する。つまり、薄膜が選択的にエッ
チングされる条件で、基板の表面に達するまでエッチン
グを行って、凹凸の高低差を薄膜の厚さに等しくする。
例えば、回折格子の凹凸の高低差を０．５μｍとする場
合、基板上に厚さ０．５μｍの薄膜を設けておけばよい
ことになる。When a thin film is used as a diffraction grating, the height difference between the irregularities is defined by the thickness of the thin film. That is, the etching is performed until the thin film reaches the surface of the substrate under the condition that the thin film is selectively etched, so that the height difference of the unevenness is made equal to the thickness of the thin film.
For example, when the height difference of the unevenness of the diffraction grating is 0.5 μm, a thin film having a thickness of 0.5 μm may be provided on the substrate.
【０００５】[0005]
【発明が解決しようとする課題】薄膜の形成には半導体
技術で確立されている蒸着、スパッタリング等の手法が
用いられる。ところが、薄膜の厚さは、原料ガスの供給
速度をはじめとする成膜条件の変動の影響を受け易い。
このため、常時一定の厚さの薄膜を得ることは困難であ
り、回折格子の凹凸の高低差がロットごとに変動する。
その結果、回折格子の性能にばらつきが生じる。For forming a thin film, techniques such as vapor deposition and sputtering which are established in semiconductor technology are used. However, the thickness of the thin film is easily affected by fluctuations in film forming conditions such as the supply speed of the source gas.
For this reason, it is difficult to always obtain a thin film having a constant thickness, and the height difference of the unevenness of the diffraction grating varies from lot to lot.
As a result, the performance of the diffraction grating varies.
【０００６】本発明は、このような問題点に鑑みてなさ
れたもので、基板上に設けられた薄膜に回折格子が形成
された回折光学素子であって、回折性能の安定したもの
を提供することを目的とする。The present invention has been made in view of such a problem, and provides a diffractive optical element having a diffraction grating formed on a thin film provided on a substrate, which has a stable diffraction performance. The purpose is to:
【０００７】[0007]
【課題を解決するための手段】上記目的を達成するため
に、本発明では、基板と、基板上に設けられた薄膜を備
え、薄膜に回折格子が形成されている回折光学素子にお
いて、薄膜の厚さが回折格子の最上部と最下部との高低
差よりも大きいものとする。According to the present invention, there is provided a diffractive optical element comprising a substrate, a thin film provided on the substrate, and a diffraction grating formed on the thin film. It is assumed that the thickness is larger than the height difference between the uppermost portion and the lowermost portion of the diffraction grating.
【０００８】この回折光学素子では、薄膜に形成された
回折格子が基板に達する深さの凹部を有していない。す
なわち、回折格子の凹凸の高低差は、薄膜の厚さ自体で
規定されるのではなく、薄膜の加工量の制御、すなわ
ち、どれだけの深さまで加工するかで規定される。薄膜
の加工は、凹凸の高低差を精度よく設定することができ
る方法であれば、どのような方法で行ってもよいが、例
えば、従来より用いられているエッチングを採用するこ
とができる。エッチングによる加工の速度は一般に遅い
が、この特徴を逆に利用して、加工される薄膜の深さを
精度よく制御すること可能である。したがって、性能に
ばらつきのない回折光学素子となる。In this diffractive optical element, the diffraction grating formed in the thin film does not have a concave portion having a depth reaching the substrate. That is, the height difference of the unevenness of the diffraction grating is not determined by the thickness of the thin film itself, but by the control of the processing amount of the thin film, that is, by the depth of the processing. The processing of the thin film may be performed by any method as long as the method can accurately set the height difference of the unevenness. For example, etching that has been conventionally used can be employed. Although the speed of processing by etching is generally slow, it is possible to control the depth of a thin film to be processed with high accuracy by utilizing this characteristic in reverse. Therefore, the diffractive optical element has no variation in performance.
【０００９】ここで、薄膜の屈折率を基板の屈折率より
も高くするとよい。回折次数等の回折条件を同じにする
場合、必要な凹凸の高低差は屈折率に反比例する。一
方、回折効率は凹凸の高低差が小さいほど高くなる。凹
凸間の壁面に入射して失われる光が少なくなるからであ
る。したがって、薄膜の屈折率を高くすることで、凹凸
の高低差を小さくすることができ、回折効率を高めるこ
とが可能になる。Here, the refractive index of the thin film is preferably higher than the refractive index of the substrate. When the diffraction conditions such as the order of diffraction are the same, the required level difference of the unevenness is inversely proportional to the refractive index. On the other hand, the diffraction efficiency increases as the difference between the heights of the irregularities decreases. This is because less light is incident on the wall surface between the irregularities and is lost. Therefore, by increasing the refractive index of the thin film, it is possible to reduce the difference in height of the unevenness, and it is possible to increase the diffraction efficiency.
【００１０】しかも、薄膜の屈折率を基板の屈折率より
も高くすると、基板側から斜めに光を入射させる場合、
薄膜に対する光の入射角が基板に対する光の入射角より
も小さくなる。すなわち、光は回折格子に対してより垂
直に近い方向から入射する。これにより、凹凸間の壁面
に入射する光の割合が低下して、回折効率はさらに高く
なる。Further, when the refractive index of the thin film is higher than the refractive index of the substrate, when light is obliquely incident from the substrate side,
The incident angle of light on the thin film is smaller than the incident angle of light on the substrate. That is, the light is incident on the diffraction grating from a direction more perpendicular to the diffraction grating. Thereby, the ratio of the light incident on the wall surface between the irregularities is reduced, and the diffraction efficiency is further increased.
【００１１】また、薄膜の加工をエッチングで行うと、
凹凸間の壁面が傾斜面となって、回折格子全体のうち回
折に寄与し得る部位が少なくなり、回折効率の低下を招
き易い。しかし、薄膜の屈折率を高くすることで、傾斜
面が生じることによる回折効率の低下を抑えることがで
きる。上記のように凹凸の高低差が小さくなり、傾斜面
となる範囲が狭くなるからである。したがって、凹凸の
高低差を精度よく設定するために薄膜の加工にエッチン
グを採用しながら、高い回折効率を維持することができ
る。When the processing of the thin film is performed by etching,
The wall surface between the irregularities becomes an inclined surface, and a portion of the entire diffraction grating that can contribute to diffraction is reduced, and the diffraction efficiency is likely to be reduced. However, by increasing the refractive index of the thin film, it is possible to suppress a decrease in diffraction efficiency due to the generation of an inclined surface. This is because, as described above, the height difference between the irregularities becomes small, and the range of the inclined surface becomes narrow. Therefore, high diffraction efficiency can be maintained while etching is used for processing the thin film in order to accurately set the height difference of the unevenness.
【００１２】基板の材料をガラスとし、薄膜の材料をＴ
ｉＯ2、Ａｌ2Ｏ3およびＴａ2Ｏ5のいずれかとするとよ
い。これらの薄膜材料の屈折率はいずれも１．６以上で
あり、ガラスの一般的な屈折率１．５よりも大きいか
ら、回折効率を確実に高めることが可能になる。また、
成膜も容易であり、エッチングで加工することもでき
る。The material of the substrate is glass, and the material of the thin film is T
Any of iO 2 , Al 2 O 3 and Ta 2 O 5 may be used. Since the refractive index of each of these thin film materials is 1.6 or more, which is larger than the general refractive index of glass of 1.5, it is possible to reliably increase the diffraction efficiency. Also,
Film formation is easy, and processing by etching is also possible.
【００１３】薄膜に対して反対側の基板の表面に反射防
止層を備えるとよい。また、薄膜と基板の間に反射防止
層を備えてもよい。空気と基板の界面での反射や、基板
と薄膜の界面での反射が抑えられて、回折効率が一層高
くなる。It is preferable to provide an antireflection layer on the surface of the substrate opposite to the thin film. Further, an antireflection layer may be provided between the thin film and the substrate. Reflection at the interface between air and the substrate and reflection at the interface between the substrate and the thin film are suppressed, and the diffraction efficiency is further increased.
【００１４】[0014]
【発明の実施の形態】以下、本発明の回折光学素子の実
施形態について図面を参照しながら説明する。第１の実
施形態の回折光学素子１の構成を図１に模式的に示す。
回折光学素子１は基板１１、薄膜１２、および２つの反
射防止層１４、１５を備えており、薄膜１２には回折格
子１３が形成されている。回折光学素子１は、入射する
光を透過させて透過光に回折を生じさせる透過型であ
り、基板１１側から垂直に入射する光Ｌを回折させるよ
うに設定されている。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the diffractive optical element according to the present invention will be described below with reference to the drawings. FIG. 1 schematically shows the configuration of the diffractive optical element 1 according to the first embodiment.
The diffractive optical element 1 includes a substrate 11, a thin film 12, and two antireflection layers 14 and 15, on which a diffraction grating 13 is formed. The diffractive optical element 1 is of a transmission type that transmits incident light and causes diffraction of transmitted light, and is set to diffract light L that is incident perpendicularly from the substrate 11 side.
【００１５】基板１１は屈折率が約１．５のガラス製で
ある。薄膜１２は基板１１上に設けられており、その材
料は、酸化チタン（ＴｉＯ2）、酸化アルミニウム（Ａ
ｌ2Ｏ 3）および酸化タンタル（Ｔａ2Ｏ5）のいずれかで
ある。ＴｉＯ2の屈折率は約２．３、Ａｌ2Ｏ3の屈折率
は約１．６２、Ｔａ2Ｏ5の屈折率は約２．１であり、い
ずれもガラスの屈折率よりも高い。The substrate 11 is made of glass having a refractive index of about 1.5.
is there. The thin film 12 is provided on the substrate 11,
The material is titanium oxide (TiOTwo), Aluminum oxide (A
lTwoO Three) And tantalum oxide (Ta)TwoOFive)
is there. TiOTwoHas a refractive index of about 2.3 and AlTwoOThreeRefractive index
Is about 1.62, TaTwoOFiveHas a refractive index of about 2.1,
The deviation is also higher than the refractive index of glass.
【００１６】回折格子１３は薄膜１２の表面に形成され
ており、傾斜面を有するブレーズ型である。薄膜２の厚
さｄは回折格子１３の凹凸の高低差ｈよりも大きく、回
折格子１３の最下部は薄膜１２の下面に達していない。
凹凸の高低差ｈは回折対象の光Ｌの波長程度またはそれ
以下であり、薄膜１２の厚さｄは１μｍ程度である。The diffraction grating 13 is formed on the surface of the thin film 12, and is a blazed type having an inclined surface. The thickness d of the thin film 2 is larger than the height difference h of the unevenness of the diffraction grating 13, and the lowermost part of the diffraction grating 13 does not reach the lower surface of the thin film 12.
The height difference h of the unevenness is about the wavelength of the light L to be diffracted or less, and the thickness d of the thin film 12 is about 1 μm.
【００１７】反射防止層１４、１５は誘電体を多重に積
層して作製されている。反射防止層１４は、薄膜１２に
対して反対側の基板１１の表面に設けられており、空気
と基板１１の界面で生じる反射を防止する。反射防止層
１５は基板１１と薄膜１２の間に設けられており、基板
１１と薄膜１２の界面で生じる反射を防止する。The antireflection layers 14 and 15 are manufactured by laminating dielectrics in multiple layers. The antireflection layer 14 is provided on the surface of the substrate 11 opposite to the thin film 12 and prevents reflection occurring at the interface between the air and the substrate 11. The antireflection layer 15 is provided between the substrate 11 and the thin film 12, and prevents reflection occurring at the interface between the substrate 11 and the thin film 12.
【００１８】薄膜１２の屈折率が高いため、回折格子１
３の凹凸の高低差ｈは小さい。したがって、凹凸間の壁
面に入射して失われる回折後の光ＬTは僅かである。し
かも、反射防止層１４、１５により入射光Ｌの反射が抑
えられるため、回折光学素子１の回折効率は高い。な
お、反射防止層１４、１５は省略することも可能である
が、これらを備えて、できるだけ多くの光を回折格子１
３に導くのが望ましい。Since the refractive index of the thin film 12 is high, the diffraction grating 1
The height difference h of the unevenness of No. 3 is small. Therefore, the diffracted light LT that enters the wall surface between the irregularities and is lost is small. Moreover, since the reflection of the incident light L is suppressed by the antireflection layers 14 and 15, the diffraction efficiency of the diffractive optical element 1 is high. Note that the antireflection layers 14 and 15 can be omitted.
It is desirable to lead to 3.
【００１９】薄膜１２は半導体技術で確立されている真
空蒸着、スパッタリング等の種々の成膜方法で形成する
ことができる。その際、後に作製する回折格子１３の凹
凸の高低差ｈを超えるだけの厚さｄを確保すればよく、
薄膜１２の形成の制御は容易である。The thin film 12 can be formed by various film forming methods such as vacuum deposition and sputtering established in semiconductor technology. At this time, it is sufficient to secure a thickness d that exceeds the height difference h of the unevenness of the diffraction grating 13 to be manufactured later.
Control of the formation of the thin film 12 is easy.
【００２０】回折格子１３の作製すなわち薄膜１２の加
工は、加工量の制御が容易な方法によって行い、凹凸の
高低差ｈを精度よく設定する。エッチングは、一般に、
加工速度は遅いが、逆に処理時間によって加工量を調節
することが容易であり、この目的に適する。本実施形態
ではＲＩＥ（リアクティブイオンエッチング）によって
薄膜１２を加工している。The fabrication of the diffraction grating 13, that is, the processing of the thin film 12, is performed by a method that allows easy control of the processing amount, and the height difference h of the unevenness is accurately set. Etching is generally
Although the processing speed is low, it is easy to adjust the processing amount by the processing time, which is suitable for this purpose. In this embodiment, the thin film 12 is processed by RIE (reactive ion etching).
【００２１】ＲＩＥに際しては、加工を薄膜１２内にと
どめるため、反射防止層１５の材質を考慮することなく
エッチング条件を定めることができる。したがって、加
工量の調節が容易なエッチング条件を選択し易く、凹凸
の高低差ｈを精度よく設定することが可能である。At the time of RIE, the etching conditions can be determined without considering the material of the antireflection layer 15 in order to keep the processing in the thin film 12. Therefore, it is easy to select an etching condition in which the processing amount can be easily adjusted, and it is possible to accurately set the height difference h of the unevenness.
【００２２】第２の実施形態の回折光学素子２の構成を
図２に模式的に示す。回折光学素子２は回折光学素子１
と同様に構成されており、基板１１、回折格子１３が形
成されている薄膜１２、および反射防止層１４、１５を
備えている。回折光学素子２は、入射する光を反射して
反射光に回折を生じさせる反射型であり、基板１１側か
ら斜めに入射する光Ｌを回折させるように設定されてい
る。回折格子１３が反射型に設定されていることを除
き、基板１１、薄膜１２、回折格子１３、反射防止層１
４、１５の材料や作製方法等は回折光学素子１と同じで
あるので、重複する説明は省略する。FIG. 2 schematically shows the structure of the diffractive optical element 2 according to the second embodiment. Diffractive optical element 2 is diffractive optical element 1
, And includes a substrate 11, a thin film 12 on which a diffraction grating 13 is formed, and antireflection layers 14 and 15. The diffractive optical element 2 is a reflection type that reflects incident light and causes diffraction of reflected light, and is set to diffract light L obliquely incident from the substrate 11 side. Substrate 11, thin film 12, diffraction grating 13, antireflection layer 1 except that diffraction grating 13 is set to a reflection type.
Since the materials and manufacturing methods of 4 and 15 are the same as those of the diffractive optical element 1, duplicate description will be omitted.
【００２３】光Ｌを基板１１に斜めに入射させる回折光
学素子２では、回折格子１３の凹凸間の壁面に光Ｌの一
部が入射する。また、回折後の光ＬRの一部も凹凸間の
壁面に入射する。しかしながら、薄膜１２の屈折率が高
く、凹凸の高低差が小さいため、壁面で失われる光は少
ない。しかも、薄膜１２の屈折率が基板１１の屈折率よ
りも高いから、薄膜１２に対する光Ｌの入射角は基板１
１に対する入射角よりも小さくなる。このため、薄膜１
２への光Ｌの入射方向は垂直に近づき、凹凸間の壁面に
入射する光はさらに少なくなる。したがって、回折光学
素子２の回折効率は高い。In the diffractive optical element 2 in which the light L is obliquely incident on the substrate 11, a part of the light L is incident on the wall surface between the irregularities of the diffraction grating 13. Further, a part of the light LR after diffraction also enters the wall surface between the irregularities. However, since the refractive index of the thin film 12 is high and the height difference between the irregularities is small, the light lost on the wall surface is small. Moreover, since the refractive index of the thin film 12 is higher than the refractive index of the substrate 11, the angle of incidence of the light L on the thin film 12 is
It becomes smaller than the incident angle with respect to 1. Therefore, the thin film 1
The direction of incidence of the light L on 2 approaches vertical, and the amount of light incident on the wall surface between the irregularities is further reduced. Therefore, the diffraction efficiency of the diffractive optical element 2 is high.
【００２４】第３の実施形態の回折光学素子３の回折格
子１３を図３に模式的に示す。回折光学素子３では、回
折格子１３は水平面を有するバイナリ型とされている。
基板１１、回折格子１３が形成されている薄膜１２、反
射防止層１４、１５の構成や作製方法は第１の実施形態
の回折光学素子１と同様であり、重複する説明は省略す
る。FIG. 3 schematically shows the diffraction grating 13 of the diffractive optical element 3 according to the third embodiment. In the diffractive optical element 3, the diffraction grating 13 is of a binary type having a horizontal plane.
The configuration and manufacturing method of the substrate 11, the thin film 12 on which the diffraction grating 13 is formed, and the antireflection layers 14 and 15 are the same as those of the diffractive optical element 1 of the first embodiment, and the overlapping description will be omitted.
【００２５】回折光学素子３においてもＲＩＥによって
回折格子１３を作製するが、一般に、エッチングでは、
加工した部位と保存した部位の間の壁面が傾斜面とな
る。図３の（ａ）は、バイナリ型の回折格子１３の理想
的な断面を表しており、（ｂ）は実際に得られる回折格
子１３の断面を表している。バイナリ型の回折格子にこ
のような傾斜面が生じると、回折に寄与する水平面の割
合が減少して回折効率は低下する。しかしながら、回折
光学素子３の薄膜１２の屈折率は高いから、傾斜面とな
る範囲は少なく、回折効率の低下を僅かにすることがで
きる。In the diffractive optical element 3 as well, the diffraction grating 13 is manufactured by RIE.
The wall surface between the processed part and the preserved part becomes an inclined plane. FIG. 3A shows an ideal cross section of the binary diffraction grating 13, and FIG. 3B shows a cross section of the diffraction grating 13 actually obtained. When such an inclined surface is generated in the binary diffraction grating, the ratio of the horizontal plane contributing to diffraction decreases, and the diffraction efficiency decreases. However, since the refractive index of the thin film 12 of the diffractive optical element 3 is high, the range of the inclined surface is small, and the decrease in the diffraction efficiency can be slightly reduced.
【００２６】比較のために、薄膜の屈折率が小さいとき
の回折格子１３に相当する回折格子１３’を図４に示
す。図４の（ａ）は理想的な断面を、（ｂ）は実際に得
られる断面を表す。屈折率が小さいと、同じ回折条件に
設定するためには、回折格子１３’の凹凸の高低差を大
きくする必要が生じる。一方、エッチングにより生じる
傾斜面の角度は、加工の進行の程度にあまり依存せず、
略一定である。このため、図３の（ｂ）と図４の（ｂ）
の比較より明らかなように、傾斜面となる範囲Ｓが広く
なって、水平面の割合が低下する。これに対し、薄膜１
２の屈折率が高い回折光学素子３では、水平面を大きく
確保することができ、回折効率の低下は僅かになる。For comparison, FIG. 4 shows a diffraction grating 13 'corresponding to the diffraction grating 13 when the refractive index of the thin film is small. FIG. 4A shows an ideal cross section, and FIG. 4B shows an actually obtained cross section. If the refractive index is small, it is necessary to increase the difference in height of the unevenness of the diffraction grating 13 ′ in order to set the same diffraction condition. On the other hand, the angle of the inclined surface generated by the etching does not depend much on the progress of the processing,
It is almost constant. Therefore, FIG. 3 (b) and FIG. 4 (b)
As is clear from the comparison, the range S that becomes the inclined surface is widened, and the ratio of the horizontal surface is reduced. In contrast, thin film 1
In the diffractive optical element 3 having a high refractive index of 2, a large horizontal plane can be ensured, and a decrease in diffraction efficiency is slight.
【００２７】図１、図２には示していないが、第１、第
２の実施形態の回折光学素子１、２においても、回折格
子１３の凹凸間の壁面は傾斜し、回折を生じさせるため
の本来の傾斜面の割合は減少する。しかしながら、回折
光学素子１、２でも、薄膜１２の屈折率が高いため、回
折効率の低下は僅かに抑えられる。Although not shown in FIGS. 1 and 2, in the diffractive optical elements 1 and 2 of the first and second embodiments as well, the wall surface between the irregularities of the diffraction grating 13 is inclined to cause diffraction. The ratio of the original inclined surface decreases. However, even in the diffractive optical elements 1 and 2, the decrease in the diffraction efficiency is slightly suppressed because the refractive index of the thin film 12 is high.
【００２８】[0028]
【発明の効果】回折格子が形成されている薄膜の厚さが
回折格子の最上部と最下部との高低差よりも大きい本発
明の回折光学素子では、回折格子の凹凸の高低差は、薄
膜の厚さにより規定されるのではなく、薄膜の加工時の
制御で規定されるから、凹凸の高低差を精度よく設定す
ることができる。したがって、性能にばらつきのない回
折光学素子となる。According to the diffractive optical element of the present invention, in which the thickness of the thin film on which the diffraction grating is formed is larger than the height difference between the uppermost portion and the lowermost portion of the diffraction grating, the difference in height of the unevenness of the diffraction grating is reduced Is not determined by the thickness of the thin film but by the control at the time of processing the thin film, so that the height difference of the unevenness can be set accurately. Therefore, the diffractive optical element has no variation in performance.
【００２９】特に、薄膜の屈折率を基板の屈折率よりも
高くすると、回折格子の高低差を小さくすることができ
ること、回折格子に対する光の入射方向が垂直に近づく
こと、薄膜の加工の際に傾斜面が生じるときでもその範
囲が小さくなることの３つの理由により、確実に回折効
率を高めることができる。しかも、回折格子の形成に必
要な薄膜の厚さを抑えることができ、薄膜形成の効率が
向上する。In particular, when the refractive index of the thin film is higher than the refractive index of the substrate, the height difference of the diffraction grating can be reduced. Even when an inclined surface is formed, the diffraction efficiency can be surely increased for three reasons that the range becomes small. In addition, the thickness of the thin film required for forming the diffraction grating can be reduced, and the efficiency of forming the thin film is improved.
【図１】 第１の実施形態の回折光学素子の構成を模式
的に示す断面図。FIG. 1 is a sectional view schematically showing the configuration of a diffractive optical element according to a first embodiment.
【図２】 第２の実施形態の回折光学素子の構成を模式
的に示す断面図。FIG. 2 is a cross-sectional view schematically illustrating a configuration of a diffractive optical element according to a second embodiment.
【図３】 第３の実施形態の回折光学素子の回折格子の
構成を模式的に示す断面図。FIG. 3 is a sectional view schematically showing a configuration of a diffraction grating of a diffractive optical element according to a third embodiment.
【図４】 第３の実施形態の回折光学素子の比較例にお
ける回折格子の構成を模式的に示す断面図。FIG. 4 is a sectional view schematically showing a configuration of a diffraction grating in a comparative example of the diffractive optical element according to the third embodiment.
１、２、３ 回折光学素子 １１ 基板 １２ 薄膜 １３ 回折格子 １４、１５ 反射防止層 1, 2, 3 Diffractive optical element 11 Substrate 12 Thin film 13 Diffraction grating 14, 15 Antireflection layer
───────────────────────────────────────────────────── フロントページの続き (72)発明者 高田 球 大阪市中央区安土町二丁目３番13号 大阪 国際ビル ミノルタ株式会社内 (72)発明者 波多野 卓史 大阪市中央区安土町二丁目３番13号 大阪 国際ビル ミノルタ株式会社内 Ｆターム(参考） 2H049 AA03 AA07 AA37 AA45 AA46 AA53 AA57 AA59 AA63 AA64 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Takada 2-3-13 Azuchicho, Chuo-ku, Osaka Inside Osaka International Building Minolta Co., Ltd. (72) Inventor Takufumi Hatano 2-3-3 Azuchicho, Chuo-ku, Osaka-shi No. 13 Osaka International Building Minolta Co., Ltd. F-term (reference) 2H049 AA03 AA07 AA37 AA45 AA46 AA53 AA57 AA59 AA63 AA64
Claims (5)
え、薄膜に回折格子が形成されている回折光学素子にお
いて、 薄膜の厚さが回折格子の最上部と最下部との高低差より
も大きいことを特徴とする回折光学素子。1. A diffractive optical element comprising a substrate and a thin film provided on the substrate, wherein a diffraction grating is formed on the thin film. A diffractive optical element characterized in that it is also large.
ことを特徴とする請求項１に記載の回折光学素子。2. The diffractive optical element according to claim 1, wherein the refractive index of the thin film is higher than the refractive index of the substrate.
がＴｉＯ2、Ａｌ2Ｏ 3およびＴａ2Ｏ5のいずれかである
ことを特徴とする請求項２に記載の回折光学素子。3. The material of the substrate is glass, and the material of the thin film is
Is TiOTwo, AlTwoO ThreeAnd TaTwoOFiveIs one of
3. The diffractive optical element according to claim 2, wherein:
防止層を備えることを特徴とする請求項１ないし請求項
３のいずれか１項に記載の回折光学素子。4. The diffractive optical element according to claim 1, further comprising an anti-reflection layer on the surface of the substrate opposite to the thin film.
とを特徴とする請求項１ないし請求項４のいずれか１項
に記載の回折光学素子。5. The diffractive optical element according to claim 1, further comprising an antireflection layer between the thin film and the substrate.
Priority Applications (1)
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|---|---|---|---|
| JP2000368614A JP2002169010A (en) | 2000-12-04 | 2000-12-04 | Diffraction optical element |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000368614A JP2002169010A (en) | 2000-12-04 | 2000-12-04 | Diffraction optical element |
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| JP2002169010A true JP2002169010A (en) | 2002-06-14 |
Family
ID=18838810
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|---|---|---|---|
| JP2000368614A Pending JP2002169010A (en) | 2000-12-04 | 2000-12-04 | Diffraction optical element |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2004081620A1 (en) * | 2003-03-13 | 2006-06-15 | 旭硝子株式会社 | Diffraction element and optical device |
| WO2019093146A1 (en) * | 2017-11-08 | 2019-05-16 | Ａｇｃ株式会社 | Diffractive optical element |
| WO2019240010A1 (en) * | 2018-06-11 | 2019-12-19 | Ａｇｃ株式会社 | Diffraction optical element, projection device, and measurement device |
Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5577716A (en) * | 1978-12-06 | 1980-06-11 | Canon Inc | Light deflector |
| JPS6343101A (en) * | 1986-08-08 | 1988-02-24 | Toyo Commun Equip Co Ltd | Transmission type diffraction grating |
| JPS63187202A (en) * | 1987-01-30 | 1988-08-02 | Hitachi Ltd | Blazed holographic diffraction grating |
| JPS63192078A (en) * | 1987-02-04 | 1988-08-09 | Fujitsu Ltd | Production of surface relief type hologram |
| JPH0243555A (en) * | 1988-08-03 | 1990-02-14 | Kuraray Co Ltd | Pattern forming method and exposing device |
| JPH06174908A (en) * | 1992-12-10 | 1994-06-24 | Hitachi Ltd | Production of waveguide type diffraction grating |
| JPH075316A (en) * | 1993-06-18 | 1995-01-10 | Tdk Corp | Diffraction grating type polarizer and its production |
| JPH0798404A (en) * | 1993-08-02 | 1995-04-11 | Matsushita Electric Ind Co Ltd | Production of diffraction grating |
| JPH08220317A (en) * | 1994-12-09 | 1996-08-30 | Balzers Ag | Diffraction grating and manufacture of photoconductor |
| JPH1026707A (en) * | 1996-07-11 | 1998-01-27 | Sanyo Electric Co Ltd | Surface relief type diffraction grating and its manufacture |
| JPH10209533A (en) * | 1997-01-17 | 1998-08-07 | Cymer Inc | Reflective protection film for replica diffraction grating |
| JPH11237508A (en) * | 1998-02-24 | 1999-08-31 | Sankyo Seiki Mfg Co Ltd | Production of polarizable hologram element |
| JP2000321415A (en) * | 1999-03-11 | 2000-11-24 | Agency Of Ind Science & Technol | Production of diffraction grating |
| JP2000347028A (en) * | 1999-06-02 | 2000-12-15 | Ricoh Co Ltd | Diffraction grating type polarizing element |
| JP2001072442A (en) * | 1999-07-07 | 2001-03-21 | Nippon Sheet Glass Co Ltd | Method for producing article having uneven surface and article produced by the method |
| JP2001264527A (en) * | 2000-03-22 | 2001-09-26 | Sankyo Seiki Mfg Co Ltd | Diffraction optical element and method of manufacturing the same |
-
2000
- 2000-12-04 JP JP2000368614A patent/JP2002169010A/en active Pending
Patent Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5577716A (en) * | 1978-12-06 | 1980-06-11 | Canon Inc | Light deflector |
| JPS6343101A (en) * | 1986-08-08 | 1988-02-24 | Toyo Commun Equip Co Ltd | Transmission type diffraction grating |
| JPS63187202A (en) * | 1987-01-30 | 1988-08-02 | Hitachi Ltd | Blazed holographic diffraction grating |
| JPS63192078A (en) * | 1987-02-04 | 1988-08-09 | Fujitsu Ltd | Production of surface relief type hologram |
| JPH0243555A (en) * | 1988-08-03 | 1990-02-14 | Kuraray Co Ltd | Pattern forming method and exposing device |
| JPH06174908A (en) * | 1992-12-10 | 1994-06-24 | Hitachi Ltd | Production of waveguide type diffraction grating |
| JPH075316A (en) * | 1993-06-18 | 1995-01-10 | Tdk Corp | Diffraction grating type polarizer and its production |
| JPH0798404A (en) * | 1993-08-02 | 1995-04-11 | Matsushita Electric Ind Co Ltd | Production of diffraction grating |
| JPH08220317A (en) * | 1994-12-09 | 1996-08-30 | Balzers Ag | Diffraction grating and manufacture of photoconductor |
| JPH1026707A (en) * | 1996-07-11 | 1998-01-27 | Sanyo Electric Co Ltd | Surface relief type diffraction grating and its manufacture |
| JPH10209533A (en) * | 1997-01-17 | 1998-08-07 | Cymer Inc | Reflective protection film for replica diffraction grating |
| JPH11237508A (en) * | 1998-02-24 | 1999-08-31 | Sankyo Seiki Mfg Co Ltd | Production of polarizable hologram element |
| JP2000321415A (en) * | 1999-03-11 | 2000-11-24 | Agency Of Ind Science & Technol | Production of diffraction grating |
| JP2000347028A (en) * | 1999-06-02 | 2000-12-15 | Ricoh Co Ltd | Diffraction grating type polarizing element |
| JP2001072442A (en) * | 1999-07-07 | 2001-03-21 | Nippon Sheet Glass Co Ltd | Method for producing article having uneven surface and article produced by the method |
| JP2001264527A (en) * | 2000-03-22 | 2001-09-26 | Sankyo Seiki Mfg Co Ltd | Diffraction optical element and method of manufacturing the same |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPWO2004081620A1 (en) * | 2003-03-13 | 2006-06-15 | 旭硝子株式会社 | Diffraction element and optical device |
| WO2019093146A1 (en) * | 2017-11-08 | 2019-05-16 | Ａｇｃ株式会社 | Diffractive optical element |
| CN111316140A (en) * | 2017-11-08 | 2020-06-19 | Ａｇｃ株式会社 | Diffractive optical element |
| JPWO2019093146A1 (en) * | 2017-11-08 | 2020-11-26 | Ａｇｃ株式会社 | Diffractive optical element |
| JP7276139B2 (en) | 2017-11-08 | 2023-05-18 | Ａｇｃ株式会社 | Diffractive optical element |
| WO2019240010A1 (en) * | 2018-06-11 | 2019-12-19 | Ａｇｃ株式会社 | Diffraction optical element, projection device, and measurement device |
| JPWO2019240010A1 (en) * | 2018-06-11 | 2021-07-08 | Ａｇｃ株式会社 | Diffractive optics, projection and measuring devices |
| TWI803647B (en) * | 2018-06-11 | 2023-06-01 | 日商Ａｇｃ股份有限公司 | Diffractive optical element, projection device and measuring device |
| JP7310809B2 (en) | 2018-06-11 | 2023-07-19 | Ａｇｃ株式会社 | Diffractive optical element, projection device and measurement device |
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