Yoshihiro Uozu

Mutual diffusion process for continuous fabrication of graded-index plastic rod lenses.

We propose a new process for fabrication of plastic rod lenses based on the traditional method of fiber extrusion. The process consists of the following steps: multilayer conjugate extrusion, monomer diffusion between adjacent layers, and photopolymerization of an uncured strand fiber. We call this process a mutual diffusion process for continuous plastic rod lens fabrication. Characteristics of this process are as follows: fast production speed (approximately 100 cm/min), precision control of refractive-index distribution, high angular aperture, and long-term reliability. The optical resolution of the rod-lens array is 300 dpi, which is high enough for application to G3 facsimiles with transmission time of less than 1 min and monochromatic scanners.

Improvement of Chromatic Aberration of a Plastic Rod Lens Array. 1. Combination-Color Lens Arrays Consisting of Several Kinds of Rod Lenses with Different Gradient Constants and Different Color Filter Functions

We propose a new type of rod lens array with improved chromatic aberration. The new rod lens array consists of several kinds of rod lenses with different gradient constants and different color filter functions. The gradient constant of each lens was prepared such that the total conjugate length was identical to the specific wavelength of the lens with a constant lens length. We call our new type of rod lens array a combination-color lens array. The characteristics of this color-type lens array are as follows: high angular aperture, short focal length, and ease of production with established procedures. The optical resolution of the rod lens array is 300 dpi in a wide wavelength range that is high enough to be applied to color scanners.

Photopolymerization of Methacrylic Acid Esters in the Presence of a Different Methacrylic Acid Ester Polymer with Different Refractive Index. Formation of New Transparent Polymer Blends to Control Refractive Index.

プラスチック光ファイバ, ロッドレンズおよび光導波路といった屈折率分布を有する光学素子を形成するために, 数種のメタクリル酸エステル系ポリマーをそのポリマーとは屈折率の異なるポリマーを形成するモノマーあるいはモノマー混合物に均一に溶解させた状態で紫外線照射を行い, ポリマーブレンドを形成することにより, 従来の手法では相分離を起こし不透明となるポリマーの組合せに対して, 透明なポリマープレンドを実現した. この現象は, 光重合の重合速度が速く, 初期の均一状態を維持できるためと考えられる. また, メタクリル酸フッ素化アルキル系ポリマーとポリメタクリル酸メチルとのブレンドでは相溶性に関して, 水素結合の影響が確認できた. このポリマーブレンド形成技術ならびに新しい透明ポリマーブレンドは屈折率分布型透明材料の開発に非常に有用なものである.

Dyeing of the Circumferential Part of a Plastic Rod Lens for Improving its Optical Resolution

A plastic rod-lens array that we developed industrially with a continuous spinning technique has an optical resolution of 200 dpi (4 lp/mm), and it has been used for facsimile machines and other applications. However, this resolution is still insufficient for its application in image scanners, copy machines, and light emitting diode (LED) printers. During the study for improving the optical resolution of the plastic rod-lens array, we have confirmed that this resolution is determined by the deviation of refractive index distribution from the ideal one at the outer circumferential part. Therefore, we have developed a technique for dyeing the outer circumferential part of the rod lens in order to achieve the higher optical resolution power of 300 dpi (6 lp/mm).