Optical: systems and elements – Lens – With graded refractive index
Patent
1992-10-23
1994-02-15
Sugarman, Scott J.
Optical: systems and elements
Lens
With graded refractive index
359652, G02B 300
Patent
active
052872220
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention is related to graded index (abbreviated "GI" hereafter) type plastic optical transmission mediums and the manufacturing method thereof which can be used in a variety of optical transmission path applications such as light focussing optical fibers, light focussing long cylindrical lenses, and optical sensors; and in particular, it relates to optical transmission mediums and the manufacturing methods thereof which make it possible to transmit high resolution and high quality images with little color aberration.
BACKGROUND TECHNOLOGY
In recent years there have been many attempts to use long cylindrical optical transmission mediums as a means to transmit images for facsimiles, copiers and image sensors, etc. For such optical transmission mediums, it is desirable to have a product that can transmit high resolution and high quality images with little color aberration, and it is desirable to be able to adopt a manufacturing method for mass production which has few product quality variations among the optical transmission mediums.
With this kind of optical transmission medium for image transmission, a GI type optical transmission medium is used in which the refractive index becomes continuously smaller going from the center to the outer periphery within the cross-section of the optical transmission medium and in which there is an angled gradient in the distribution of the refractive index. This kind of GI type optical transmission medium appears in Japan Patent Publication No. Sho 47-816, Japan Patent Publication No. Sho 47-28059, and in EP Laid-Open Patent Application No. 208159, etc.
The GI type optical transmission medium indicated in Japan Patent Publication No. Sho 47-816 uses glass as the material, and because it is made by an ion exchange method, it has low productivity, and it is difficult to produce products between varying lots that provide the same shape and the same performance. In particular, with long cylindrical lenses of the same length that have a fixed total conjugate length, it is difficult to make products that provide the same performance between varying lots. As a result, the difficulties arise that the lengths of the GI type optical transmission mediums which provide the same performance are not uniform, and that handling them becomes troublesome.
The GI type plastic optical transmission mediums that are indicated in Japan Patent Publication No. Sho 47-28059 are made by dipping into a particular solvent long cylindrical shaped or fiber shaped molded products consisting of a mixture of 2 or more transparent polymers that have different refractive indices and which have different solubility in relation to said solvent, thus changing the percentage of mixture of the aforementioned 2 or more polymers going from the surface of said molding to its center. Plastic GI type optical transmission mediums can more or less be made by this method, but products that are a mixture of 2 or more polymers having different refractive indices can easily produce turbulence in the distribution of the refractive index, and it is difficult to make a product with a shape in which the refractive index distribution follows the optimum distribution curve from the core toward the outer periphery. Moreover products are made in which the transparency of the optical transmission medium is lowered, and the light scattering can easily occur. Thus, the characteristics are not sufficient as a GI type optical transmission medium, and this does not promote applications and development.
In EP Laid-Open Patent Application No. 0208159, a method is indicated in which, after molding into a rod shape a uniform mixture of at least one kind of thermoplastic polymer (A) and of monomer (B) which when polymerized is compatible with polymer (A) and which becomes a polymer with a refractive index that differs from polymer (A), and after making a continuous concentration distribution of monomer (B) going from the surface of said molded product to the center by dispersing monomer (B) from the surface of the mo
REFERENCES:
patent: 3626194 (1971-12-01), Hirano et al.
patent: 3827785 (1974-08-01), Matsushita et al.
patent: 4215914 (1980-08-01), Muchel et al.
patent: 4587065 (1986-05-01), Kouichi et al.
patent: 4689000 (1987-08-01), Kouichi et al.
Rawson, et al., "Analysis of Refractive Index Distributions in Cylindrical Graded-Index Glass Rods (GRIN Rods) Used as Image Rays" Applied Optics, vol. 9, No. 3 Mar. 1970 p. 753.
Hoshide Yoshihiko
Mise Kouzou
Toyoda Nobuhiko
Uozu Yoshihiro
Lester Evelyn A.
Mitsubishi Rayon Co. Ltd.
Sugarman Scott J.
LandOfFree
Graded index type plastic optical transmission mediums and the m does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Graded index type plastic optical transmission mediums and the m, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Graded index type plastic optical transmission mediums and the m will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1211662