【０００１】
【発明の属する技術分野】
本発明は撮像素子の光路中に配置して、該撮像素子に入射する光量を調整するために、入射光量に応じて透過率を変化させて、撮像素子に入射する光量を適正な範囲にすることができる光量調整素子に関するものである。
【０００２】
【従来の技術】
撮像素子は一般に適正な光入射がなされたときに正確に画像出力が行える。例えば入射光が強すぎるときはハレーションが生じたり、弱すぎるときは中間調の再現性がわるくなるといった不都合が生じる。
【０００３】
このために、撮像素子に入射する光量を調整する目的で、特開平５−４０２８２には、レンズ系中の絞り部材よりも像面側に配置された正の屈折力又は負の屈折力を持つ少なくとも１つのレンズに、入射光の強弱によって光学的な濃度が変化する光学素子を設けて、通過光量を制御する光量調節手段が開示されている。
【０００４】
係る発明はレンズ系中の絞り部材よりも像面側にフォトクロミックガラスにより構成した正の屈折力又は負の屈折力を持つ少なくとも１つのレンズを配置している。このフォトクロミックガラスが入射光の強弱によって光学的な濃度が変化することで光量調節を行う素子である。
【０００５】
【発明が解決しようとする課題】
しかしながら、特開平５−４０２８２で開示された光量調整装置は
・フォトクロミックガラスを用いるため応答速度が遅く、光量調整を瞬時に行うことができない。
・透過率が入射光量とフォトクロミックガラスの着色特性に依存し、透過率の制御が困難である。
といった問題点を抱えている。
【０００６】
またこれら光量調整素子は前記撮像素子に取り付ける際には、レンズなどの光学系を伴うことが多く、実装体積を大きくする要因ともなっていた。
【０００７】
【課題を解決するための手段】
本発明者は、上記の課題を解決するために、前記光量調整素子を構成する透明基板の形状をレンズ状とすることによって、光量を調整するだけではなく、レンズ機能を備える素子を提供した。特に本発明は光量調光素子をレンズとして機能させることを特徴としていて、素子の実装体積を小さくする上で効果的である。
【０００８】
本発明の第１の特徴的な構成は、
実質的に透明な第一及び第二基板を対向して配置し、対向する前記両基板の少なくとも一方の面に複数の透明電極を備え、該両基板間に電気的な信号を与えて光学的透過率が変化する光量調整層を配置した光量調整素子であって、前記両基板の４つの基板面の少なくとも一面が曲面をなして光学レンズ効果を有することを特徴とする光量調整素子である。
【０００９】
また本発明は、前記光量調整層が複数の透明電極と透明絶縁性液体、及び該透明絶縁性液体中に分散された複数の不透明帯電泳動粒子からなる電気泳動素子であることを特徴としている。
【００１０】
さらに本発明は、前記第一基板と前記第二基板間に形成される光量調整層の厚みが基板上の位置に従って変化することを特徴とする光量調整素子である。
【００１１】
【発明の実施の形態】
以下、本発明の実施態様について順に説明する。
【００１２】
図１に本発明の代表的な断面構成図を、図４に本発明の代表的な平面図を示す。一方が平面で一方が曲面の第一基板１と、同様に一方が平面で一方が曲面の第二基板２を、各凸面を外側に向けて対向して配置した。
【００１３】
第一基板１と第二基板２の対向面側には、第一基板１の対向面側には第１電極７と第３電極９を、第二基板２の対向面側には第２電極８と第４電極１０をそれぞれ配置した。それぞれの電極は透明であり、その平面構成は図４に示すようにそれぞれ半径の異なる環状でそれらを同心円状に配置した。
【００１４】
さらに電極表面に絶縁層３を配置して、間隙支持材を介して対向配置した。この空隙中に、電界印加によって光学的透過率が変化する光量調整層として、不透明帯電泳動粒子５を分散した透明絶縁性液体６を充填した。
【００１５】
第一基板１と第二基板２の表面形状は、１つ以上の表面が曲面でかつ本素子を通過する光線束を発散もしくは収束させて、画像を結ぶ構成であれば特に限定しない。形状は凸状でも凹状でもよい。
【００１６】
または凹凸を組み合わせた形状でもよい。第一基板１、第二基板２は、実質的に光学的に透明である。なお、本発明において、実質的に透明であるとは、光透過率が可視光域（波長４００−７００ｎｍ）或は変調しようとする波長領域において、７０％以上、好ましくは８０％以上、より好ましくは９０％以上であることを意味する。
【００１７】
光量調整層は電気的信号により光学的透過率が変化する構成であればどのようなものでもよい。電気泳動現象を利用したもの、液晶、エレクトロクロミック素子、ポッケルス効果ケル効果に基づく素子を利用したもの、あるいは銀塩溶液から電極上への銀の析出を利用したもの（特開平１０−２７４７９０に開示されている）でもよい。
【００１８】
電極形状は光量調整層の透過率を変化させうる構成であれば特に限定しない。第一基板１・第二基板２の対向面側の一面に電極を配置してもよいし、それぞれの基板上で図４、図５のように特定のパターンを持ってもよい。いずれの場合にも光量調整層の透過率を効果的に変化せしめられる形状であれば良い。電極は一方の基板にのみ配置されていてもよいし、図２のように両方の基板に配置されていてもよい。
【００１９】
本構成ではそれぞれ半径の異なる環状でそれらを同心円状に配置したが、例えば図５に示すように、帯状の電極を素子中央から遠心方向に０度以上の角度をもって、かつ素子中央からの距離に依存してその角度を変化させる構成でもよい。あるいはストライプ状電極を並べて配置する構成でも良い。環状の電極を同心円状に配置する場合、電極の一部に隙間を設け配線を配置する構成とすればよい。電極材料は透明電極を用いるのが好ましい。
【００２０】
絶縁層３の有無は光量調整層の透過率を効果的に変化できれば特に限定しない。銀塩溶液から電極上への銀の析出を利用する場合絶縁層無しの構成が好ましく、電気泳動現象を利用した構成の場合不透明帯電泳動粒子への電荷の注入を避けるために絶縁層を設けた方が好ましい。絶縁層材料も実質的に透明であれば特に限定しない。エポキシなどの樹脂でも良いしＳｉＯ２などの酸化物でも良い。
【００２１】
間隙支持体４の有無、配置場所は特に限定しないが、図５のように素子周囲に配置する構成は好ましい構成のひとつである。素子周囲に配置することで封止剤として機能する。もちろん間隙支持体４と封止剤を別々に設けてもよい。
【００２２】
光量調整層として透明絶縁性液体６と不透明帯電泳動粒子５を充填し電気泳動現象を利用して透過率を変化させる構成は良い構成の一つである。電気泳動現象を利用した構成の場合、透光時の透過率が高く、透光時と遮光時の屈折率の変化がほとんどなく、また電気化学的な反応過程が無いことから耐久性も高いことが挙げられる。
【００２３】
光量調整層に電気泳動現象を利用した構成を用いる場合、電極形状は特に限定しないが、図２のように第一基板１と第二基板２の間隙幅に依存して、電極幅を変化させる構成は好ましい構成の一つである。例えば図５に示すように、素子周辺部の基板間隔が素子中央部の基板間隔に比べて広い場合、素子周辺部に向かって電極幅が広くなる構成が好ましい例である。
【００２４】
光量調整層に電気泳動現象を利用した構成を用いる場合、素子に開口部１２と非開口部１１を設ける構成は好ましい構成の一つである。素子が透光時には不透明帯電泳動粒子５を非開口部１１に分布させ、素子が遮光時には開口部１２に不透明帯電泳動粒子５を分布させる駆動方法が考えられる。非開口部１１は素子周辺部にあっても素子中央部にあっても良い。
【００２５】
第一基板１と第二基板２の間隔が広い領域を非開口部１１とする構成は好ましい構成のひとつである（図２）。基板間隔が広い領域は不透明帯電泳動粒子５を多く分布できることから、非開口部１１を小さくでき、素子の小型化が可能になる。素子に非開口部１１を設ける場合、開口部１２のを通過する光線束を発散・収束させて実像もしくは虚像を結ぶ構成であればよい（図３）。非開口部１１の断面形状は特に限定しない。
【００２６】
光の入射や散乱を防止するために非開口部１１に対応する領域を不透明にする構成は好ましい構成の一つである（図２）。非開口部１１が不透明になれば構成は特に限定しない。非開口部１１に対応した領域の電極を不透明な材料で作製しても良いし、一部が透明で一部が不透明の基板を第一基板１および／もしくは第二基板２に用いてもよいし、第一基板１および／もしくは第二基板２を不透明に着色してもよい。または不透明な基板で非開口部１１を覆う構成でも良い。
【００２７】
各電極に所望の電圧を印加する駆動回路３８と素子を通過する光量を測定する光量測定手段を備えることは好ましい構成である。光量測定手段はどのようなものでも良い。例えば電荷結合素子などの撮像素子３６を光量測定手段に用いて、その出力に依存して適切な透過率になるように駆動回路３８により本素子を制御すればよい。また本素子３５の適用方法は特に限定しないが、撮像モジュール３２、および撮像装置３１などに適用するのは良い適用方法である。
【００２８】
【実施例】
以下、実施例に従って本発明を説明する。
【００２９】
（実施例１）
本実施例では、図１に示す断面構成で、図４に示す平面構成の素子を作製し駆動を行った。作製した素子の大きさは直径１ｍｍ、厚さ０．５ｍｍである。
【００３０】
まず、第一基板１として厚さ０．２ｍｍのガラスを図に示す断面形状に形成し基板の対抗面側にＩＴＯを低温成膜し、フォトリソグラフィー及びエッチングにより図に示す形状にパターニングした。続いて、絶縁部３としてＳｉＯ２を製膜した。この上に、間隙支持体４を形成した。間隙支持体４は、光感光性エポキシ樹脂を塗布した後、露光及びウエット現像を行うことによって形成し、１００μｍの高さとした。形成された空間内に絶縁性液体６及び不透明帯電泳動粒子５を充填した。絶縁性液体６としては、イソパラフィンを使用した。不透明帯電泳動粒子５としては、ポリスチレンとカーボンの混合物で、平均粒径２μｍ位のものを使用した。イソパラフィン中での不透明帯電泳動粒子５は正帯電極性を示した。次に、第二基板２として厚さ０．２ｍｍのガラスを図１に示す断面形状に形成し基板の対抗面側にＩＴＯを低温成膜し、フォトリソグラフィー及びエッチングにより図に示す形状にパターニングした。続いて、絶縁部３としてＳｉＯ２を製膜した。この第二基板２を位置合わせを行ないながら第一基板１上に置き、素子周辺部を接着剤により張り合わせた。
【００３１】
これに駆動装置３８を接続して駆動を行った。電極に電気信号を印加し不透明帯電泳動粒子５を素子周辺部の電極上から順次素子中央の電極上へと泳動させたところ、素子全体に分散していた不透明帯電泳動粒子を素子中央に搬送させ透光状態とした。駆動電圧は１０Ｖである。また、第一基板１上の電極と第二基板２上の電極をそれぞれ電気的に接続して異なる電圧を交互に印加したところ、素子中央に分散していた不透明帯電泳動粒子５は素子全体に分散され、素子開口部は遮光状態となった。駆動電圧は最高１０Ｖである。
【００３２】
本素子を撮像装置３１に取り付けて駆動させたところ、明所から暗所まで良好な画像を得ることができた。
【００３３】
（実施例２）
本実施例では、図３に示す断面構成で、図４に示す平面構成の素子を作製し駆動を行った。作製した素子の大きさは直径１ｍｍ、厚さ０．５ｍｍである。
【００３４】
まず、第一基板１として厚さ０．２ｍｍのガラスを図に示す断面形状に形成した。次いで非開口部１１を不透明に着色した。次いで基板の対抗面側にＩＴＯを低温成膜し、フォトリソグラフィー及びエッチングにより図４に示す形状にパターニングした。続いて、絶縁部３としてＳｉＯ２を製膜した。この上に、間隙支持体４を形成した。間隙支持体４は、光感光性エポキシ樹脂を塗布した後、露光及びウエット現像を行うことによって形成し、１００μｍの高さとした。形成された空間内に絶縁性液体６及び不透明帯電泳動粒子５を充填した。絶縁性液体６としては、イソパラフィンを使用した。不透明帯電泳動粒子５としては、ポリスチレンとカーボンの混合物で、平均粒径２μｍ位のものを使用した。イソパラフィン中での不透明帯電泳動粒子５は正帯電極性を示した。次に、第二基板２として厚さ０．２ｍｍのガラスを図に示す断面形状に形成した。次いで非開口部１１を不透明に着色した。次いで基板の対抗面側にＩＴＯを低温成膜し、フォトリソグラフィー及びエッチングにより図に示す形状にパターニングした。続いて、絶縁部３としてＳｉＯ２を製膜した。この第二基板２を位置合わせを行ないながら第一基板１上に置き、素子周辺部を接着剤により張り合わせた。
【００３５】
これに駆動装置３８を接続して駆動を行った。電極に駆動電圧は１０Ｖの電気信号を印加し不透明帯電泳動粒子５を素子周辺部の電極上から順次素子中央の電極上へと泳動させたところ、素子全体に分散していた不透明帯電泳動粒子５を素子中央に搬送させ遮光状態となった。
【００３６】
また、電極に駆動電圧は１０Ｖの電気信号を印加し不透明帯電泳動粒子を素子中央部の電極上から順次素子周辺の電極上へと泳動させたところ、素子中央に分散していた不透明帯電泳動粒子５は素子周辺に搬送され、素子開口部は透光状態となった。
【００３７】
本素子を撮像装置３８に取り付けて駆動させたところ、明所から暗所まで良好な画像を得ることができた。
【００３８】
また本素子の他の構成例を図８に示す。
【００３９】
８５は本発明の光量調整素子であり、基板がレンズ形状になっている。８４は通常の光学レンズであり、本発明の基板と合わせて撮像素子８６に対する結像効果を持つ。
【００４０】
使用するレンズの枚数は、少なくとも結像面で所望の像が得られればよく、特に制限はない。また光量調整素子は光軸上に配置すれば配置に関して特に限定しない。レンズ装置の最前面に配置する構成は好ましい例の一つだが、それに限定しない。レンズ装置を構成するレンズの枚数は特に限定しない。複数枚で構成しても良いし、光量調整素子のみでもよい。
【００４１】
本発明の光量調整素子は、基板自体がレンズ形状になっているために、他のレンズの使用枚数を減らすことが可能であり、撮像装置の実装上有効である。
【００４２】
【発明の効果】
以上、詳細に述べたように、本発明によって次のような効果が得られた。
【００４３】
第一に、１つの素子でレンズとしての機能を持つ光量調整素子を提供した。これによりこれまで小型化が困難であった撮像モジュール、撮像装置を大幅に小型化できた。
【００４４】
【図面の簡単な説明】
【図１】本発明の光量調整素子の代表的な断面図の一例を示す。
【図２】本発明の光量調整素子の代表的な断面図の一例を示す。
【図３】本発明の光量調整素子の代表的な断面図の一例を示す。
【図４】本発明の光量調整素子の代表的な平面図の一例を示す。
【図５】本発明の光量調整素子の代表的な平面図の一例を示す。
【図６】本発明の光量調整素子の代表的な平面図の一例を示す。
【図７】本発明の光量調整装置の代表的な構成例を示す。
【図８】本発明の光量調整装置の他の構成例を示す。
【符号の説明】
１ 第一基板
２ 第二基板
３ 絶縁部
４ 間隙支持体
５ 不透明帯電泳動粒子
６ 絶縁性液体
７ 第１電極
８ 第２電極
９ 第３電極
１０ 第４電極
１１ 遮光部
１２ 開口部
３１ 撮像装置
３２ 撮像モジュール
３５ 光量調整素子
３６ 撮像素子
３７ 撮像素子駆動装置
３８ 駆動装置
３９ 記憶装置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is arranged in the optical path of an image sensor, and in order to adjust the amount of light incident on the image sensor, the transmittance is changed according to the amount of incident light so that the amount of light incident on the image sensor is in an appropriate range. The present invention relates to a light amount adjusting element capable of performing the above operation.
[0002]
[Prior art]
In general, an image sensor can accurately output an image when proper light incidence is performed. For example, when the incident light is too strong, halation occurs, and when the incident light is too weak, halftone reproducibility deteriorates.
[0003]
For this purpose, Japanese Patent Application Laid-Open No. H5-40282 discloses a lens having a positive refractive power or a negative refractive power which is disposed closer to the image plane than a diaphragm member in a lens system in order to adjust the amount of light incident on the image sensor. There is disclosed a light-amount adjusting means for providing at least one lens with an optical element whose optical density changes according to the intensity of incident light and controlling the amount of light passing therethrough.
[0004]
In this invention, at least one lens having a positive refractive power or a negative refractive power made of photochromic glass is disposed on the image plane side of the stop member in the lens system. This photochromic glass is an element that adjusts the amount of light by changing the optical density depending on the intensity of incident light.
[0005]
[Problems to be solved by the invention]
However, the light amount adjusting device disclosed in Japanese Patent Application Laid-Open No. H5-40282 has a low response speed because photochromic glass is used, and light amount adjustment cannot be performed instantaneously.
-The transmittance depends on the amount of incident light and the coloring characteristics of the photochromic glass, and it is difficult to control the transmittance.
There is a problem such as.
[0006]
In addition, when these light amount adjusting elements are attached to the image pickup element, they often involve an optical system such as a lens, which has been a factor of increasing the mounting volume.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventor has provided an element having not only a light amount adjustment but also a lens function by making a shape of a transparent substrate constituting the light amount adjustment element into a lens shape. In particular, the present invention is characterized in that the light intensity control device functions as a lens, and is effective in reducing the mounting volume of the device.
[0008]
A first characteristic configuration of the present invention is:
Substantially transparent first and second substrates are arranged facing each other, a plurality of transparent electrodes are provided on at least one surface of the two substrates facing each other, and an electrical signal is applied between the two substrates to provide an optical signal. A light quantity adjusting element provided with a light quantity adjusting layer whose transmittance changes, wherein at least one of the four substrate surfaces of the two substrates has a curved surface to have an optical lens effect.
[0009]
Further, the present invention is characterized in that the light quantity adjusting layer is an electrophoretic element including a plurality of transparent electrodes, a transparent insulating liquid, and a plurality of opaque charged electrophoretic particles dispersed in the transparent insulating liquid.
[0010]
Further, the present invention is the light amount adjusting element, wherein a thickness of the light amount adjusting layer formed between the first substrate and the second substrate changes according to a position on the substrate.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in order.
[0012]
FIG. 1 is a typical sectional view of the present invention, and FIG. 4 is a typical plan view of the present invention. A first substrate 1 having one flat surface and one curved surface, and a second substrate 2 having one flat surface and one curved surface are arranged to face each other with their convex surfaces facing outward.
[0013]
A first electrode 7 and a third electrode 9 are provided on the opposing surface side of the first substrate 1 on the opposing surface side of the second substrate 2, and a second electrode is provided on the opposing surface side of the second substrate 2. 8 and the fourth electrode 10 were arranged respectively. Each of the electrodes was transparent, and the plane configuration thereof was concentrically arranged in annular shapes having different radii as shown in FIG.
[0014]
Further, an insulating layer 3 was arranged on the electrode surface, and was opposed to each other via a gap supporting material. The gap was filled with a transparent insulating liquid 6 in which opaque charged electrophoretic particles 5 were dispersed, as a light amount adjusting layer whose optical transmittance was changed by application of an electric field.
[0015]
The surface shape of the first substrate 1 and the second substrate 2 is not particularly limited as long as at least one surface is a curved surface and a light beam passing through the device is diverged or converged to form an image. The shape may be convex or concave.
[0016]
Alternatively, the shape may be a combination of irregularities. The first substrate 1 and the second substrate 2 are substantially optically transparent. In the present invention, “substantially transparent” means that the light transmittance is 70% or more, preferably 80% or more, more preferably 80% or more in a visible light region (wavelength 400 to 700 nm) or a wavelength region to be modulated. Means 90% or more.
[0017]
The light amount adjusting layer may be of any structure as long as the optical transmittance changes according to an electric signal. A device utilizing an electrophoretic phenomenon, a device utilizing a liquid crystal, an electrochromic device, a device based on the Pockels effect, or a device utilizing the deposition of silver from a silver salt solution onto an electrode (disclosed in JP-A-10-274790) Has been).
[0018]
The shape of the electrode is not particularly limited as long as it can change the transmittance of the light quantity adjusting layer. Electrodes may be arranged on one surface of the first substrate 1 and the second substrate 2 facing each other, or each substrate may have a specific pattern as shown in FIGS. In any case, any shape may be used as long as the transmittance of the light amount adjustment layer can be effectively changed. The electrodes may be arranged on only one substrate, or may be arranged on both substrates as shown in FIG.
[0019]
In the present configuration, they are arranged concentrically in annular shapes having different radii. For example, as shown in FIG. 5, the strip-shaped electrodes are arranged at an angle of 0 degree or more in the centrifugal direction from the center of the element and at a distance from the center of the element. The angle may be changed depending on the angle. Alternatively, a configuration in which stripe-shaped electrodes are arranged side by side may be used. When the annular electrodes are arranged concentrically, a configuration may be adopted in which a gap is provided in a part of the electrodes and wiring is arranged. It is preferable to use a transparent electrode as the electrode material.
[0020]
The presence or absence of the insulating layer 3 is not particularly limited as long as the transmittance of the light amount adjusting layer can be effectively changed. In the case of using silver deposition from a silver salt solution on an electrode, a configuration without an insulating layer is preferable.In the case of a configuration using an electrophoretic phenomenon, an insulating layer is provided to avoid injection of charges into opaque charged electrophoretic particles. Is more preferred. The material of the insulating layer is not particularly limited as long as it is substantially transparent. A resin such as epoxy or an oxide such as SiO 2 may be used.
[0021]
The presence / absence of the gap support 4 and the location thereof are not particularly limited, but a configuration arranged around the element as shown in FIG. 5 is one of preferred configurations. By arranging it around the element, it functions as a sealant. Of course, the gap support 4 and the sealant may be provided separately.
[0022]
A configuration in which the transparent insulating liquid 6 and the opaque charged electrophoretic particles 5 are filled as the light amount adjusting layer and the transmittance is changed by using the electrophoresis phenomenon is one of the good configurations. In the case of the configuration utilizing the electrophoresis phenomenon, the transmittance at the time of light transmission is high, there is almost no change in the refractive index at the time of light transmission and at the time of light shielding, and the durability is high because there is no electrochemical reaction process. Is mentioned.
[0023]
In the case where a configuration utilizing the electrophoresis phenomenon is used for the light quantity adjusting layer, the electrode shape is not particularly limited, but the electrode width is changed depending on the gap width between the first substrate 1 and the second substrate 2 as shown in FIG. The configuration is one of the preferred configurations. For example, as shown in FIG. 5, when the substrate interval at the element peripheral portion is wider than the substrate interval at the element central portion, a configuration in which the electrode width increases toward the element peripheral portion is a preferable example.
[0024]
When a configuration utilizing an electrophoresis phenomenon is used for the light amount adjustment layer, a configuration in which an opening 12 and a non-opening 11 are provided in the element is one of preferred configurations. A driving method in which the opaque charged electrophoretic particles 5 are distributed in the non-opening portions 11 when the element is light-transmitting, and the opaque charged electrophoretic particles 5 are distributed in the opening portions 12 when the element is shielded from light. The non-opening 11 may be at the peripheral portion of the device or at the central portion of the device.
[0025]
A configuration in which a region where the distance between the first substrate 1 and the second substrate 2 is large is set as the non-opening portion 11 is one of preferable configurations (FIG. 2). Since the opaque charged electrophoretic particles 5 can be distributed more in the region where the substrate spacing is wide, the non-opening portion 11 can be reduced, and the element can be downsized. In the case where the non-aperture 11 is provided in the element, any configuration may be used as long as a light beam passing through the aperture 12 is diverged and converged to form a real image or a virtual image (FIG. 3). The cross-sectional shape of the non-opening 11 is not particularly limited.
[0026]
A configuration in which a region corresponding to the non-opening portion 11 is made opaque in order to prevent incidence and scattering of light is one of preferred configurations (FIG. 2). The configuration is not particularly limited as long as the non-opening 11 becomes opaque. The electrode in the region corresponding to the non-opening 11 may be made of an opaque material, or a partially transparent and partially opaque substrate may be used for the first substrate 1 and / or the second substrate 2. Then, the first substrate 1 and / or the second substrate 2 may be colored opaquely. Alternatively, the non-opening 11 may be covered with an opaque substrate.
[0027]
It is a preferable configuration to include a drive circuit 38 for applying a desired voltage to each electrode and a light amount measuring unit for measuring the amount of light passing through the element. The light amount measuring means may be of any type. For example, an image sensor 36 such as a charge-coupled device may be used as a light amount measuring unit, and the driving circuit 38 may control the present device so as to obtain an appropriate transmittance depending on the output. The application method of the present element 35 is not particularly limited, but it is a good application method to apply to the imaging module 32, the imaging device 31, and the like.
[0028]
【Example】
Hereinafter, the present invention will be described with reference to examples.
[0029]
(Example 1)
In this example, the device having the cross-sectional configuration shown in FIG. 1 and the planar configuration shown in FIG. 4 was manufactured and driven. The size of the manufactured element is 1 mm in diameter and 0.5 mm in thickness.
[0030]
First, glass having a thickness of 0.2 mm was formed as the first substrate 1 in a cross-sectional shape shown in the figure, and ITO was formed at a low temperature on the opposite surface of the substrate, and patterned into the shape shown in the figure by photolithography and etching. Subsequently, a film of SiO 2 was formed as the insulating portion 3. The gap support 4 was formed thereon. The gap support 4 was formed by applying a photosensitive epoxy resin, and then performing exposure and wet development to have a height of 100 μm. The formed space was filled with the insulating liquid 6 and the opaque charged electrophoretic particles 5. As the insulating liquid 6, isoparaffin was used. As the opaque electrophoretic particles 5, a mixture of polystyrene and carbon having an average particle size of about 2 μm was used. The opaque charged electrophoretic particles 5 in isoparaffin showed a positively charged polarity. Next, a glass having a thickness of 0.2 mm was formed as the second substrate 2 in a cross-sectional shape shown in FIG. 1, ITO was formed at a low temperature on the opposite surface of the substrate, and patterned by photolithography and etching into a shape shown in the drawing. . Subsequently, a film of SiO 2 was formed as the insulating portion 3. The second substrate 2 was placed on the first substrate 1 while performing alignment, and the peripheral portion of the element was bonded with an adhesive.
[0031]
Driving was performed by connecting a driving device 38 to this. When an opaque charged electrophoretic particle 5 was electrophoresed from an electrode on the periphery of the element to an electrode in the center of the element sequentially by applying an electric signal to the electrode, the opaque charged electrophoretic particles dispersed throughout the element were conveyed to the center of the element. It was in a light transmitting state. The drive voltage is 10V. When the electrodes on the first substrate 1 and the electrodes on the second substrate 2 were electrically connected to each other and different voltages were applied alternately, the opaque charged electrophoretic particles 5 dispersed in the center of the device became over the entire device. It was dispersed, and the element opening was in a light-shielding state. The drive voltage is up to 10V.
[0032]
When this element was mounted on the imaging device 31 and driven, a good image could be obtained from a bright place to a dark place.
[0033]
(Example 2)
In the present example, an element having a cross-sectional configuration shown in FIG. 3 and a planar configuration shown in FIG. 4 was manufactured and driven. The size of the manufactured element is 1 mm in diameter and 0.5 mm in thickness.
[0034]
First, glass having a thickness of 0.2 mm was formed as the first substrate 1 into a cross-sectional shape shown in the figure. Next, the non-opening portion 11 was colored opaquely. Next, ITO was formed at a low temperature on the opposite surface side of the substrate, and was patterned into the shape shown in FIG. 4 by photolithography and etching. Subsequently, a film of SiO 2 was formed as the insulating portion 3. The gap support 4 was formed thereon. The gap support 4 was formed by applying a photosensitive epoxy resin, and then performing exposure and wet development to have a height of 100 μm. The formed space was filled with the insulating liquid 6 and the opaque charged electrophoretic particles 5. As the insulating liquid 6, isoparaffin was used. As the opaque electrophoretic particles 5, a mixture of polystyrene and carbon having an average particle size of about 2 μm was used. The opaque charged electrophoretic particles 5 in isoparaffin showed a positively charged polarity. Next, glass having a thickness of 0.2 mm was formed as the second substrate 2 in a sectional shape shown in the figure. Next, the non-opening portion 11 was colored opaquely. Next, ITO was formed at a low temperature on the opposite surface side of the substrate, and was patterned into the shape shown in the figure by photolithography and etching. Subsequently, a film of SiO 2 was formed as the insulating portion 3. The second substrate 2 was placed on the first substrate 1 while performing alignment, and the peripheral portion of the element was bonded with an adhesive.
[0035]
Driving was performed by connecting a driving device 38 to this. When an electric signal of a driving voltage of 10 V is applied to the electrodes to cause the opaque charged electrophoretic particles 5 to migrate sequentially from the electrodes at the peripheral portion of the device onto the electrode at the center of the device, the opaque charged electrophoretic particles 5 dispersed throughout the device are obtained. Was transported to the center of the device, and a light-shielded state was obtained.
[0036]
When an electric signal with a driving voltage of 10 V was applied to the electrodes to cause the opaque charged electrophoretic particles to migrate from the electrode at the center of the element to the electrodes around the element sequentially, the opaque charged electrophoretic particles dispersed at the center of the element were observed. 5 was conveyed to the periphery of the element, and the opening of the element was in a light transmitting state.
[0037]
When this element was mounted on the image pickup device 38 and driven, a good image could be obtained from a bright place to a dark place.
[0038]
FIG. 8 shows another configuration example of the present element.
[0039]
Reference numeral 85 denotes a light amount adjusting element of the present invention, and the substrate has a lens shape. Reference numeral 84 denotes a normal optical lens, which has an image forming effect on the image sensor 86 in combination with the substrate of the present invention.
[0040]
The number of lenses to be used is not particularly limited as long as a desired image can be obtained at least on the image forming surface. The arrangement of the light quantity adjusting element is not particularly limited as long as it is arranged on the optical axis. The arrangement arranged at the forefront of the lens device is one of preferred examples, but is not limited thereto. The number of lenses constituting the lens device is not particularly limited. It may be composed of a plurality of sheets, or only a light amount adjusting element.
[0041]
Since the substrate itself has a lens shape, the light amount adjusting element of the present invention can reduce the number of other lenses used, and is effective in mounting an imaging device.
[0042]
【The invention's effect】
As described above, the following effects were obtained by the present invention.
[0043]
First, a light amount adjusting element having a function as a lens with one element was provided. As a result, the size of the imaging module and the imaging device, which have been difficult to miniaturize, can be significantly reduced.
[0044]
[Brief description of the drawings]
FIG. 1 shows an example of a typical sectional view of a light quantity adjusting element of the present invention.
FIG. 2 shows an example of a typical cross-sectional view of a light quantity adjusting element of the present invention.
FIG. 3 shows an example of a typical cross-sectional view of a light quantity adjusting element of the present invention.
FIG. 4 shows an example of a typical plan view of a light amount adjusting element of the present invention.
FIG. 5 shows an example of a typical plan view of a light quantity adjusting element of the present invention.
FIG. 6 shows an example of a typical plan view of a light quantity adjusting element of the present invention.
FIG. 7 shows a typical configuration example of a light quantity adjusting device according to the present invention.
FIG. 8 shows another configuration example of the light amount adjusting device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 2nd board | substrate 3 Insulating part 4 Gap support 5 Opaque charged electrophoretic particle 6 Insulating liquid 7 First electrode 8 Second electrode 9 Third electrode 10 Fourth electrode 11 Light shielding part 12 Opening 31 Imaging device 32 Image pickup module 35 Light intensity adjustment element 36 Image pickup element 37 Image pickup element drive unit 38 Drive unit 39 Storage unit
