JPH07104107A - Fresnel lens - Google Patents
Fresnel lensInfo
- Publication number
- JPH07104107A JPH07104107A JP25274593A JP25274593A JPH07104107A JP H07104107 A JPH07104107 A JP H07104107A JP 25274593 A JP25274593 A JP 25274593A JP 25274593 A JP25274593 A JP 25274593A JP H07104107 A JPH07104107 A JP H07104107A
- Authority
- JP
- Japan
- Prior art keywords
- annular
- ring
- zone
- outer peripheral
- fresnel lens
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Diffracting Gratings Or Hologram Optical Elements (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は,光ディスク等の光学的
情報機器など,光応用システムの微小光学素子として用
いられるフレネルレンズの改良に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a Fresnel lens used as a micro optical element of an optical application system such as an optical information device such as an optical disk.
【0002】[0002]
【従来の技術】図3に従来構造になるフレネルレンズF
Lの直径方向の部分断面図を示す。図3において,光軸
30を中心として同心円状に複数形成された各輪帯3
1,32…を通過して焦点面に至る光の位相差が光の波
長の整数倍になるように各輪帯31,32…の位置及び
形状が形成されている。即ち,レンズの焦点距離をf,
光の波長をλ,レンズを構成する物質の屈折率をns,
光軸30からの半径方向の距離をRとすると,m番目の
輪帯32とm−1番目の輪帯31との境界位置Rmは,
光軸30を通って焦点に至る光34と,位置Rmを通っ
て焦点に至る光36との位相差が波長の整数倍となるよ
うに,下式(1)で与えられる。2. Description of the Related Art FIG. 3 shows a Fresnel lens F having a conventional structure.
A partial sectional view of L in the diameter direction is shown. In FIG. 3, a plurality of annular zones 3 are formed concentrically around the optical axis 30.
The positions and shapes of the respective ring zones 31, 32, ... Are formed so that the phase difference of the light passing through the focal planes through 1, 32. That is, the focal length of the lens is f,
The wavelength of the light is λ, the refractive index of the material forming the lens is ns,
Assuming that the radial distance from the optical axis 30 is R, the boundary position Rm between the m-th ring zone 32 and the (m-1) th ring zone 31 is
The phase difference between the light 34 reaching the focus through the optical axis 30 and the light 36 reaching the focus through the position Rm is given by the following equation (1) so that the phase difference is an integral multiple of the wavelength.
【数1】 又,m番目の輪帯32を通った光36と,m−1番目の
輪帯31を通った光35との焦点における位相差は,例
えば,各輪帯31,32の最も内径側を通る光に対して
計算すると,下式(2)のようになり,波長の整数倍と
な,この場合,1倍となっている。[Equation 1] Further, the phase difference at the focal point between the light 36 passing through the m-th ring zone 32 and the light 35 passing through the (m-1) th ring zone 31 passes, for example, on the innermost side of each ring zone 31, 32. When calculated for light, it becomes as shown in the following formula (2), which is an integral multiple of the wavelength, and in this case, it is 1.
【数2】 更に,m番目の輪帯32の位置Rmからの径方向の変位
rmでの高さhmは,下式(3)のように与えられる。 hm=(λ+a−b)/(ns−f/b)…(3)[Equation 2] Further, the height hm at the radial displacement rm from the position Rm of the m-th ring zone 32 is given by the following expression (3). hm = (λ + a−b) / (ns−f / b) ... (3)
【数3】 更に,m番目の輪帯32の幅dmは,下式(4)のよう
に与えられる。 dm=Rm−Rm−1…(4) 上記輪帯32の位置及び形状の例に示したように,光軸
30を中心に同心円に形成される各輪帯の幅は,外周方
向に離れるほど狭くなる。これを具体例に適用した場合
で示すと,輪帯幅dmは図4に示すような変化となる。
この例は,波長0.6328μmのレーザー光を焦点距
離5mmの位置に集光させるフレネルレンズの場合であ
る。[Equation 3] Further, the width dm of the m-th ring zone 32 is given by the following equation (4). dm = Rm-Rm-1 (4) As shown in the example of the position and shape of the ring zone 32, the width of each ring zone formed concentrically around the optical axis 30 becomes more distant in the outer circumferential direction. Narrows. When this is applied to a specific example, the ring zone width dm changes as shown in FIG.
This example is a case of a Fresnel lens that focuses laser light having a wavelength of 0.6328 μm at a position with a focal length of 5 mm.
【0003】上記のように構成される微小サイズのフレ
ネルレンズは,電子ビーム描画法,レーザービーム描画
法,機械加工法などの方法によって製作することができ
る。中でも大気中で高精度な加工ができるレーザービー
ム描画法が注目されている。この方法は,透明な平面に
形成されたレンズ基板上にフォトレジストを塗布して,
レーザービームで露光させ,現像処理することによって
レンズ基板の表面にフォトレジストの薄膜により所要の
形状が形成される。図5に示すように,フォトレジスト
が塗布されたレンズ基板20を回転させつつ,細く絞ら
れたレーザービーム21により露光させることによって
円形の露光パターンが形成され,更にレンズ基板20を
所定方向に送ることで,同心円状の露光パターンが得ら
れる。これを現像処理することによってレンズ基板20
上に複数の輪帯が形成されたフレネルレンズを製作する
ことができる。フォトレジストが現像液に溶ける速さは
レーザービーム21による露光量に依存するので,レー
ザービーム21の露光量を制御することにより,フォト
レジストの深さ方向の掘れ量が制御される。この技術に
よって得られるフレネルレンズは,非常に薄く小型のも
のを製作でき,薄膜で形成されているため周囲の温度変
動による焦点距離変動がほとんどないなどの優れた特徴
を有している。The Fresnel lens having a minute size configured as described above can be manufactured by a method such as an electron beam drawing method, a laser beam drawing method, or a machining method. Above all, the laser beam drawing method, which can perform highly accurate processing in the atmosphere, is drawing attention. This method applies photoresist on a lens substrate formed on a transparent plane,
A desired shape is formed by a thin film of photoresist on the surface of the lens substrate by exposing with a laser beam and developing. As shown in FIG. 5, while rotating the lens substrate 20 coated with photoresist, a circular exposure pattern is formed by exposing with a laser beam 21 that is narrowed down, and further the lens substrate 20 is sent in a predetermined direction. As a result, a concentric exposure pattern can be obtained. By developing this, the lens substrate 20
A Fresnel lens having a plurality of ring zones formed thereon can be manufactured. Since the speed at which the photoresist dissolves in the developing solution depends on the exposure amount of the laser beam 21, by controlling the exposure amount of the laser beam 21, the digging amount of the photoresist in the depth direction is controlled. The Fresnel lens obtained by this technique is extremely thin and small, and because it is formed of a thin film, it has the excellent characteristics that there is almost no change in focal length due to temperature changes in the surroundings.
【0004】[0004]
【発明が解決しようとする課題】しかしながら,フレネ
ルレンズでは集光性能を向上させるために開口数を上げ
ようとすると,輪帯の幅は狭くせざるを得ず,上記輪帯
の形成式に示したように半径方向に輪帯幅が狭くなる外
周方向の輪帯部分では,レーザービームのビーム径に係
る加工精度の限界が生じ,フレネルレンズとしての回折
効率に重大な影響を及ぼす問題点があった。即ち,図6
に示すフレネルレンズの設計断面において,鋸歯状に形
成された輪帯31,32,33を有限の太さを有するレ
ーザービームで加工するとき,輪帯31…の幅が小さい
場合には,輪帯間の境界部分のエッジのダレが発生し,
実際の加工形状は図示破線で示すような形状となってし
まう。従来例において図4に示した輪帯幅の計算例で
は,レーザービーム径が1.5μmとすると,m=10
以上の輪帯では,輪帯幅に対してレーザービーム径が1
0%以上を占めることになり,輪帯の10%程度の領域
では形状精度が得られない。本発明は上記従来の問題点
に鑑みて創案されたもので,有限の太さを有するレーザ
ービーム径によって加工が困難になる部位の少ないレン
ズ構造によって回折効率に優れたフレネルレンズを提供
することを目的とする。However, in the Fresnel lens, when trying to increase the numerical aperture in order to improve the light-collecting performance, the width of the ring zone is inevitably narrowed, which is shown in the above formula for forming the ring zone. As described above, there is a problem that in the annular zone portion in the outer circumferential direction where the annular zone width is narrowed in the radial direction, there is a limit to the processing accuracy related to the beam diameter of the laser beam, which seriously affects the diffraction efficiency as a Fresnel lens. It was That is, FIG.
In the design cross section of the Fresnel lens shown in Fig. 3, when the serrated annular zones 31, 32, 33 are processed by a laser beam having a finite thickness, the annular zones 31 ... Edge sagging at the boundary between
The actual processed shape becomes the shape shown by the broken line in the figure. In the conventional example of calculating the ring width shown in FIG. 4, when the laser beam diameter is 1.5 μm, m = 10
In the above rings, the laser beam diameter is 1 with respect to the width of the rings.
Since it occupies 0% or more, the shape accuracy cannot be obtained in the area of about 10% of the ring zone. The present invention was devised in view of the above conventional problems, and it is an object of the present invention to provide a Fresnel lens having excellent diffraction efficiency with a lens structure having a small number of portions that are difficult to process due to a laser beam diameter having a finite thickness. To aim.
【0005】[0005]
【課題を解決するための手段】上記目的を達成するため
に本発明が採用する第1の手段は,入射される光を回折
させて所定距離隔てた焦点上に集光させるための回折格
子を構成する複数の輪帯がレンズ基板表面に同心円状に
形成され,隣り合う輪帯からの回折光の上記焦点での位
相差が上記入射される光の波長に所定の整数値を掛けた
値となり,且つ上記回折格子の間隔が外周方向に次第に
狭くなるような形状及び位置に上記各輪帯が形成されて
なるフレネルレンズにおいて,上記輪帯が,1の輪帯群
の中では上記整数値の値が一定であり,上記整数値が隣
り合う輪帯群間で差があり外周方向の輪帯群ほど大きく
なる複数の輪帯群に分けて形成されてなることを特徴と
するフレネルレンズとして構成されている。又,本発明
が採用する第2の手段は,入射される光を回折させて所
定距離隔てた焦点上に集光させるための回折格子を構成
する複数の輪帯がレンズ基板表面に同心円状に形成さ
れ,隣り合う輪帯からの回折光の上記焦点での位相差が
上記入射される光の波長に所定の整数値を掛けた値とな
り,且つ上記回折格子の間隔が外周方向に次第に狭くな
るような形状及び位置に上記各輪帯が形成されてなるフ
レネルレンズにおいて,上記輪帯の断面が外周方向に傾
斜する略三角形状で,該三角形状の底辺を輪帯幅とする
回析格子間隔に形成され,該複数の輪帯が外径方向に複
数の輪帯群に区分され,外周方向の輪帯群ほど上記整数
値が大きくなるような幅と高さに形成されてなることを
特徴とするフレネルレンズとして構成されている。In order to achieve the above object, the first means adopted by the present invention is a diffraction grating for diffracting incident light and condensing it on a focus at a predetermined distance. A plurality of ring zones are formed concentrically on the lens substrate surface, and the phase difference at the focus of the diffracted light from the adjacent ring zones is the value obtained by multiplying the wavelength of the incident light by a predetermined integer value. Further, in a Fresnel lens in which the respective ring zones are formed in a shape and a position such that the intervals of the diffraction grating are gradually narrowed in the outer peripheral direction, the ring zones have an integer value within the ring zone group of one. A Fresnel lens having a constant value and being formed by being divided into a plurality of orbicular zones that have a larger integer value and are larger between adjacent orbicular zones Has been done. Further, the second means adopted by the present invention is that a plurality of orbicular zones forming a diffraction grating for diffracting incident light and condensing the diffracted light on focal points separated by a predetermined distance are concentrically formed on the lens substrate surface. The phase difference of the diffracted light from the adjacent orbicular zones at the focal point becomes a value obtained by multiplying the wavelength of the incident light by a predetermined integer value, and the interval of the diffraction grating becomes gradually narrower in the outer peripheral direction. In a Fresnel lens in which each of the above-mentioned ring zones is formed in such a shape and position, the cross section of the ring zone is a substantially triangular shape inclined in the outer peripheral direction, and the diffraction grating spacing is such that the base of the triangle shape is the ring zone width. The plurality of orbicular zones are divided into a plurality of orbicular zone groups in the outer diameter direction, and the annular zone groups in the outer circumferential direction are formed to have a width and height such that the integer value becomes larger. And is configured as a Fresnel lens.
【0006】[0006]
【作用】本発明によれば,回折格子を構成する複数の輪
帯の幅が外周方向に次第に狭くなるような形状に形成さ
れるフレネルレンズにおいて,上記輪帯が外周方向に複
数の輪帯群に分けて形成され,外周方向の輪帯群ほど回
折光の焦点における位相差の整数倍値が大きく設定され
る。従って,従来構成において一定の上記整数倍値であ
る場合に外周方向に至るほど輪帯幅が狭くなって加工の
精度が得られない問題点が,輪帯群毎に上記整数倍値に
応じた輪帯幅に大きくできることで解消される。この構
成が請求項1に該当する。上記輪帯群に分けて構成され
る輪帯の形成は,略三角形状の輪帯が鋸歯状に連続する
フレネルレンズにおいて,外周方向の輪帯群ほど上記三
角形状の底辺を輪帯幅とする輪帯の幅と高さとを上記整
数倍値に応じて2倍,3倍,…と徐々に大きくすること
によって実現される。この構成が請求項2に該当する。According to the present invention, in a Fresnel lens formed in a shape in which the width of a plurality of annular zones forming a diffraction grating is gradually narrowed in the outer peripheral direction, the annular zones are composed of a plurality of annular zone groups in the outer peripheral direction. Are formed separately, and the integer multiple of the phase difference at the focus of the diffracted light is set to be larger for the ring zone in the outer peripheral direction. Therefore, in the conventional configuration, when the integer multiple value is constant, the annular zone width becomes narrower toward the outer peripheral direction, and the accuracy of machining cannot be obtained. It can be solved by increasing the width of the zone. This configuration corresponds to claim 1. The formation of the annular zones divided into the above annular zones is such that, in a Fresnel lens in which approximately triangular annular zones are continuous in a sawtooth shape, the triangular base is set to have an annular zone width in the circumferential zone. This is realized by gradually increasing the width and height of the ring zone by 2 times, 3 times, ... According to the integer multiple value. This configuration corresponds to claim 2.
【0007】[0007]
【実施例】以下,添付図面を参照して,本発明を具体化
した実施例につき説明し,本発明の理解に供する。尚,
以下の実施例は本発明を具体化した一例であって,本発
明の技術的範囲を限定するものではない。ここに,図1
は本発明の一実施例に係るフレネルレンズの直径方向の
部分断面図,図2は図1に示す輪帯群B位置の拡大断面
図である。図1において,フレネルレンズ1は,レンズ
基板2上に塗布されたフォトレジストをレーザー描画法
によって輪帯パターンが露光された後,現像処理するこ
とによってレンズ基板2上に図示するような第1の輪帯
群m1 と第2の輪帯群m2とが形成される。中心軸3寄
りの第1の輪帯群m1 では,当該フレネルレンズ1に入
射される光が隣り合う輪帯11,12…を通って焦点に
集光されたときの焦点における位相差が入射される光の
波長の1倍になるように輪帯11,12…の幅が設定さ
れている。又,外周寄りの第2の輪帯群m2 では,当該
フレネルレンズ1に入射される光が隣り合う輪帯21,
22…を通って焦点に集光されたときの焦点における位
相差が入射される光の波長の2倍になるように輪帯2
1,22…の幅が設定されている。上記第1の輪帯群m
1 は,従来例で示した輪帯と同じ形状に形成されてい
る。従って,第1の輪帯群m1 の構成については従来例
の説明を流用する。図2に拡大図示するように,中心軸
3から外周方向に所定の回折格子間隔で形成される輪帯
11,12…の中心軸3からα番目に相当する輪帯αま
でを第1の輪帯群m1 とし,従来構成のごとく第2の輪
帯群m2 が形成されない場合の輪帯αより外周方向にα
+1番目,α+2番目…の輪帯21,22…の2つずつ
を1つにまとめて第2の輪帯群m2 が形成されている。Embodiments of the present invention will be described below with reference to the accompanying drawings for the understanding of the present invention. still,
The following example is an example embodying the present invention and does not limit the technical scope of the present invention. Figure 1
FIG. 2 is a partial cross-sectional view of a Fresnel lens according to an embodiment of the present invention in the diametrical direction, and FIG. 2 is an enlarged cross-sectional view of the ring zone group B position shown in FIG. In FIG. 1, the Fresnel lens 1 is formed on the lens substrate 2 by performing a development process after exposing the photoresist coated on the lens substrate 2 to a ring pattern by a laser drawing method. A ring group m 1 and a second ring group m 2 are formed. In the first ring zone group m 1 closer to the central axis 3, the phase difference at the focus when the light incident on the Fresnel lens 1 passes through the adjacent ring zones 11, 12, ... The widths of the ring zones 11, 12, ... Are set so as to be one time the wavelength of the emitted light. Further, in the second ring zone group m 2 closer to the outer circumference, the ring zones 21 in which the lights incident on the Fresnel lens 1 are adjacent to each other,
22 is adjusted so that the phase difference at the focal point when it is focused on the focal point through 22 ... Is twice the wavelength of the incident light.
Widths of 1, 22, ... Are set. The first ring group m
1 is formed in the same shape as the ring zone shown in the conventional example. Therefore, the description of the conventional example is applied to the configuration of the first ring zone group m 1 . As shown in the enlarged view of FIG. 2, the first ring is formed from the central axis 3 of the annular zones 11, 12 ... The zone group m 1 is defined by α in the outer peripheral direction from the zone α in the case where the second zone group m 2 is not formed as in the conventional configuration.
A second ring zone group m 2 is formed by combining two of the + 1st, α + 2nd ... Zones 21, 22.
【0008】上記のように第1の輪帯群m1 の外周方向
に第2の輪帯群m2 を形成することにより,第2の輪帯
群m2 での隣り合う輪帯21,22…を通った光の焦点
における位相差は,該光の波長の2倍になるので,第2
の輪帯群m2 に属する輪帯21,22…の高さは次のよ
うに設定される。図2において,第2の輪帯群m2 の最
内周の輪帯21からβ番目の輪帯26の輪帯25との境
界位置Rm2 から半径方向への変位rm2 での高さhm
2 は,下式のように与えられる。 0≦rm2 <Rm1 −Rm1 −1のとき, hm2 =hm1 −1(rm1 =rm2 )+hm1 (rm
1 =0) Rm1 −Rm1 −1≦rm2 <Rm1 +1−Rm1 −1
のとき, hm2 =hm1 (rm1 =rm2 ) ここで,m2 =0,1,2… m2 =(m1 −mα)/2−1 上記のように第2の輪帯群m2 が形成されることによ
り,該第2の輪帯群m2の領域において輪帯数を少なく
構成することができ,輪帯幅が狭くなる領域において輪
帯境界部の形状精度が得られない従来構成における問題
点が改善される。上記実施例においては,第2の輪帯群
m2 に属する輪帯21,22…の隣り合う輪帯を通った
光の焦点における位相差を該光の波長の2倍に設定して
いるが,これを3倍,4倍のような整数倍とすることも
できる。又,輪帯群は上記実施例のごとく2群に限ら
ず,更に多く設定することもできる。更に,輪帯はレン
ズの使用目的に応じて必ずしも真円である必要はなく,
楕円形であっても本発明の効果を損なうことはない。[0008] By forming a second annular zone group m 2 in a first outer circumferential direction of the annular zone group m 1 as described above, annular zone adjacent the second annular zone group m 2 21, 22 Since the phase difference at the focal point of the light passing through is twice the wavelength of the light,
The heights of the ring zones 21, 22, ... That belong to the ring zone group m 2 are set as follows. In FIG. 2, the height hm at the radial displacement rm 2 from the boundary position Rm 2 between the innermost ring zone 21 of the second ring zone group m 2 and the ring zone 25 of the β-th ring zone 26.
2 is given by the following equation. When 0 ≦ rm 2 <Rm 1 −Rm 1 −1, hm 2 = hm 1 −1 (rm 1 = rm 2 ) + hm 1 (rm
1 = 0) Rm 1 −Rm 1 −1 ≦ rm 2 <Rm 1 +1 −Rm 1 −1
Then, hm 2 = hm 1 (rm 1 = rm 2 ), where m 2 = 0,1,2 ... m 2 = (m 1 −mα) / 2−1 As described above, the second ring group by m 2 is formed, it is possible to reduce configure the number of zones in the area of the annular zone group m 2 of the second, the annular boundary shape accuracy of the region in the annular width is reduced to obtain The problem in the conventional configuration which does not exist is improved. In the above embodiment, the phase difference at the focal point of the light passing through the adjacent ring zones of the ring zones 21, 22 ... Which belong to the second ring group m 2 is set to twice the wavelength of the light. , This can be an integral multiple such as 3 times or 4 times. Further, the number of ring zones is not limited to two as in the above-described embodiment, and more can be set. Furthermore, the ring zone does not necessarily have to be a perfect circle depending on the intended use of the lens,
The elliptical shape does not impair the effects of the present invention.
【0009】[0009]
【発明の効果】本発明は以上の説明の通り構成されるの
で,従来構成において外周方向に至るほど輪帯幅が狭く
なって加工の精度が得られない問題点が,輪帯群毎に輪
帯幅を大きく設定できることで解消される。上記輪帯群
に分けて構成される輪帯の形成は,略三角形状の輪帯が
鋸歯状に連続するフレネルレンズにおいて,外周方向の
輪帯群ほど上記三角形状の底辺を輪帯幅とする輪帯の幅
と高さとを整数倍に大きくすることによって実現され
る。Since the present invention is configured as described above, there is a problem that in the conventional configuration, the annular zone width becomes narrower toward the outer peripheral direction and the machining accuracy cannot be obtained. It can be solved by setting a large band width. The formation of the annular zones divided into the above annular zones is such that, in a Fresnel lens in which approximately triangular annular zones are continuous in a sawtooth shape, the triangular base is set to have an annular zone width in the circumferential zone. It is realized by increasing the width and height of the ring zone by an integral multiple.
【図1】 本発明の実施例に係るフレネルレンズの構成
を直径方向の部分断面ずで示す模式図。FIG. 1 is a schematic view showing a configuration of a Fresnel lens according to an example of the present invention without a partial cross section in a diameter direction.
【図2】 同上レンズの部分拡大断面図。FIG. 2 is a partially enlarged sectional view of the same lens.
【図3】 従来構成に係るフレネルレンズの構成を示す
部分断面図。FIG. 3 is a partial cross-sectional view showing a configuration of a Fresnel lens according to a conventional configuration.
【図4】 同上レンズの輪帯幅の変化を示すグラフ。FIG. 4 is a graph showing changes in the annular zone width of the same lens.
【図5】 フレネルレンズの製作方法を示す模式図。FIG. 5 is a schematic view showing a method of manufacturing a Fresnel lens.
【図6】 従来構成による微小輪帯形成の問題点を説明
する模式図。FIG. 6 is a schematic diagram illustrating a problem of forming a minute annular zone according to a conventional configuration.
1…フレネルレンズ 2…レンズ基板 11〜13…第1の輪帯 21〜23…第2の輪帯 m1 …第1の輪帯群 m2 …第2の輪帯群1 ... the Fresnel lens 2 ... Lens substrates 11 to 13 ... first annular 21-23 ... second annular m 1 ... first annular zone group m 2 ... second annular zone group
Claims (2)
た焦点上に集光させるための回折格子を構成する複数の
輪帯がレンズ基板表面に同心円状に形成され,隣り合う
輪帯からの回折光の上記焦点での位相差が上記入射され
る光の波長に所定の整数値を掛けた値となり,且つ上記
回折格子の間隔が外周方向に次第に狭くなるような形状
及び位置に上記各輪帯が形成されてなるフレネルレンズ
において,上記輪帯が次の(1)及び(2)の条件を満
たす複数の輪帯群に分けて形成されてなることを特徴と
するフレネルレンズ。 (1)1の輪帯群の中では上記整数値の値が一定であ
る。 (2)上記整数値が隣り合う輪帯群間で差があり,外周
方向の輪帯群ほど大きくなっている。1. A plurality of orbicular zones that form a diffraction grating for diffracting incident light and condensing them on a focal point separated by a predetermined distance are concentrically formed on the lens substrate surface, and The phase difference of the diffracted light at the focal point becomes a value obtained by multiplying the wavelength of the incident light by a predetermined integer value, and the above-mentioned shape and position are such that the intervals of the diffraction grating are gradually narrowed in the outer peripheral direction. A Fresnel lens having an annular zone, wherein the annular zone is formed by being divided into a plurality of annular zone groups satisfying the following conditions (1) and (2). (1) The value of the integer value is constant in the ring zone group of 1. (2) There is a difference in the above-mentioned integer value between the adjacent ring zones, and the larger the ring zone group in the outer peripheral direction is.
た焦点上に集光させるための回折格子を構成する複数の
輪帯がレンズ基板表面に同心円状に形成され,隣り合う
輪帯からの回折光の上記焦点での位相差が上記入射され
る光の波長に所定の整数値を掛けた値となり,且つ上記
回折格子の間隔が外周方向に次第に狭くなるような形状
及び位置に上記各輪帯が形成されてなるフレネルレンズ
において,上記輪帯の断面が外周方向に傾斜する略三角
形状で,該三角形状の底辺を輪帯幅とする回析格子間隔
に形成され,上記複数の輪帯が外径方向に複数の輪帯群
に区分され,且つ外周方向の輪帯群ほど上記整数値が大
きくなる形状に形成されてなることを特徴とするフレネ
ルレンズ。2. A plurality of orbicular zones that form a diffraction grating for diffracting incident light and condensing them on a focal point separated by a predetermined distance are formed concentrically on the lens substrate surface, and The phase difference of the diffracted light at the focal point becomes a value obtained by multiplying the wavelength of the incident light by a predetermined integer value, and the above-mentioned shape and position are such that the intervals of the diffraction grating are gradually narrowed in the outer peripheral direction. In a Fresnel lens in which an annular zone is formed, the annular zone has a substantially triangular cross-section inclined in the outer peripheral direction, and the plurality of annular zones are formed at diffraction grating intervals with the base of the triangular zone as the annular zone width. A Fresnel lens, characterized in that the band is divided into a plurality of ring groups in the outer diameter direction, and the ring group in the outer circumferential direction has a shape in which the integer value increases.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP25274593A JPH07104107A (en) | 1993-10-08 | 1993-10-08 | Fresnel lens |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP25274593A JPH07104107A (en) | 1993-10-08 | 1993-10-08 | Fresnel lens |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH07104107A true JPH07104107A (en) | 1995-04-21 |
Family
ID=17241693
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP25274593A Pending JPH07104107A (en) | 1993-10-08 | 1993-10-08 | Fresnel lens |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH07104107A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015515640A (en) * | 2012-02-27 | 2015-05-28 | イービジョン スマート オプティクス インコーポレイテッド | Electroactive lens with multiple depth diffractive structures |
-
1993
- 1993-10-08 JP JP25274593A patent/JPH07104107A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2015515640A (en) * | 2012-02-27 | 2015-05-28 | イービジョン スマート オプティクス インコーポレイテッド | Electroactive lens with multiple depth diffractive structures |
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