Nippon Sheet Glass Company, Limited

Sharp Kabushiki Kaisha Corporation

Fujikura Limited

Kouji Tanaka

Masahiro Oikawa

Tetsuya Yamasaki

Eiji Okuda

Fumiaki Funada

Hiroshi Hamada

Kenjiro Hamanaka

Takashi Tsumanuma

Kazuo Sanada

Naoki Shamoto

Katsuyuki Seto

Toshiyuki Tanaka

An image display apparatus includes a display panel unit having a plurality of pixels, and a flat-plate microlens array of a refraction index distribution type. The microlens array is constituted by forming a plurality of microlenses for converging illuminating light onto the respective ones of the pixels, in a substrate by a diffusion process. In the diffusion process, diffusion fronts of the neighboring microlenses of the flat-plate microlens array are fused into each other so as to form one continuous curved surface within the substrate.

Image display apparatus with microlens plate having mutually fused

In a plate microlens of the invention, wherein gradient index lenses each having an optical axis along a normal to a surface of a transparent base and a refractive index profile gradually changing along a direction of the optical axis and a direction perpendicular thereto are formed integrally in the transparent base; a ratio d/a (where d is a thickness of the gradient index lens on the optical axis and 2a is a diameter of the gradient index lens on a surface of the transparent base) falls within a range of 0.46 to 0.78. In a method for manufacturing a plate microlens of the invention, of forming integrally in a transparent base, gradient index lenses with a gradient index profile based on a concentration gradient of a substance for increasing the refractive index of the transparent base, by forming a diffusion preventive mask with predetermined apertures on a surface of the transparent base and diffusing the substance into the transparent base through the apertures; a ratio a/rm (where rm is a radius of the apertures and a is a radius of the gradient index lenses to be formed) satisfies a relation 1.75.ltoreq.a/rm.ltoreq.4.5.

Method of making a plate microlens

An image fiber preform for use in an image fiber according to the present invention includes a plurality of optical fiber strands, each optical fiber strand including a silica glass core which contains a dopant for increasing a refractive index of the core and a silica glass cladding surrounding the silica glass core, the silica glass cladding containing a fluorine dopant for decreasing a refractive index of the cladding, the cladding having an outer peripheral surface, and a quartz tube in which the optical fibers are closely arranged, wherein the cladding has a concentration of the fluorine dopant which decreases radially outward toward the outer peripheral surface of the cladding. in the present invention, an image fiber prepared from the image fiber preform and fabrication processes for the image fiber preform and the image fiber are provided.

Image fiber, image fiber preform, and manufacturing processes thereof

In a plate microlens of the invention wherein gradient index lenses each having an optical axis along a normal to a surface of a transparent base and a refractive index profile gradually changing along a direction of the optical axis and a direction perpendicular thereto are formed integrally in the transparent base, a ratio d/a (where d is a thickness of the gradient index lens on the optical axis and 2a is a diameter of the gradient index lens on a surface of the transparent base) falls within a range of 0.46 to 0.78. In a method for manufacturing a plate microlens of the invention of forming integrally in a transparent base gradient index lenses with a gradient index profile based on a concentration gradient of a substance for increasing the refractive index of the transparent base, by forming a diffusion preventive mask with predetermined apertures on a surface of the transparent base and diffusing the substance into the transparent base through the apertures, a ratio a/rm (where rm is a radius of the apertures and a is a radius of the gradient index lenses to be formed) satisfies a relation 1.75.ltoreq.a/rm.ltoreq.4.5.

Plate microlens and method for manufacturing the same

Growing community of inventors

Sakura, Japan

Kouji Tanaka