JPH0243502A - Plate lens - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention Summary of the Invention [In a flat plate lens in which at least one lens is formed on a plate-shaped substrate, at least one portion of the substrate other than the lens forming portion protrudes beyond the lens forming portion. form a protrusion. As a result, the planar lenses can be easily connected to each other and to other optical systems, and depending on the shape of the protruding portion, the lenses can be protected from scratches, lumps, etc.

TECHNICAL FIELD The present invention relates to a flat lens in which at least one lens having a protruding portion is formed on a flat substrate.

Prior art and its problems A typical example of a conventional flat plate lens is a flat Fresnel lens, particularly a flat micro Fresnel lens. This is a micro Fresnel lens having concentric circles, concentric ellipses, and other uneven structures in which the zone period becomes smaller toward the outer periphery on a transparent substrate.

Since such a flat micro Fresnel lens uses a flat substrate, other optical elements such as a deflection element and a lens element are integrated on the surface of the substrate opposite to the surface on which the Fresnel fist lens is formed. It has the advantage of being able to be formed precisely.

However, it is not easy to couple the surface of the substrate on which the Fresnel lens is formed with other optical elements. Furthermore, it is not necessarily easy to assemble an optical system that obtains an erect, equal-magnification image by laminating a plurality of such flat micro Fresnel lenses.

Furthermore, since the Fresnel lens is formed protruding from the transparent substrate, the Fresnel lens is easily damaged and scratched. Another problem is that dust tends to accumulate in the four zones of the Fresnel lens, which tends to adversely affect the optical properties of the lens.

Some of the above-mentioned problems are not limited to Fresnel lenses, but also lenses that protrude from the substrate surface (for example, aspherical lenses).
This applies to all flat lenses formed by

Summary of the Invention Purpose of the Invention The present invention can prevent damage to lenses, and also facilitates, simplifies, and miniaturizes the production of an optical system even when the optical system is produced by laminating multiple lenses. The purpose is to provide a flat plate lens.

Structure and Effects of the Invention The present invention provides a flat plate lens in which at least one lens is formed on a flat plate-shaped substrate, in which a protrusion that protrudes beyond the lens forming part at at least one part of the substrate excluding the lens forming part is provided. It is characterized by having a section.

The protruding portion may be integrally molded with the substrate or may be bonded to the substrate. It is preferable that the protrusion is formed on the entire periphery of the substrate, but it may be provided on a part of one periphery or a portion other than the periphery. There are various types of lenses formed on the substrate, such as micro Fresnel lenses and aspheric lenses. Further, one lens may be provided on the substrate, or a plurality of lenses may be arranged in an array.

According to this invention, J! A protrusion that protrudes beyond the lens formation part is formed in the part of the plate other than the part where the lens is formed, and the presence of this protrusion protects the lens on the board, making it difficult for the lens to be scratched. . Further, by providing a protective material using this protrusion or by combining another optical element or a flat lens to cover the lens, it becomes difficult for dust etc. to adhere to the lens.

Further, by utilizing the protrusion, it is possible to form a laminated structure containing a plurality of flat lenses, and the position of each flat lens can be made accurate. Since no coupling member is required, the optical system can be downsized.

Further, the flat lens according to the present invention can be easily applied to an optical fiber coupling device. For example, flat lenses can be attached to the end faces of optical fibers, and the projections can be used to combine the flat lenses on the end faces of two optical fibers to be combined. In this way, the flat lens can be attached directly to the optical fiber, and a coupling member is not required, making it possible to simplify the coupling optical system.

DESCRIPTION OF EMBODIMENTS FIG. 1 is a perspective view showing an embodiment of a flat lens according to the present invention. The flat plate lens 1 is a substrate 3. A Fresnel lens 4 provided on this substrate 3. and a protruding edge 2 protruding around the substrate 3 so as to surround the Fresnel lens 4. As is well known, the Fresnel lens 4 is composed of a concentric pattern of concave and convex portions whose intervals become narrower toward the outside. The protruding edge 2 is provided on the surface of the substrate 3 on which the Fresnel lens 4 is provided.
It has a height that projects more than the most protruding part of the convex part of the lens 4.

Such a flat plate lens 1 has a Fresnel lens 4 on a substrate 3.
injection molding method, optical polymerization method (Pboto-Polym
It can be manufactured by integrally molding using a method such as erlzatlon, and then adhering the protrusion 2 of a predetermined height to the substrate 3. Furthermore, the Fresnel lens 4 and the protrusion 2 can be integrally molded together with the substrate 3 by the method described above. Furthermore, the Fresnel lens 4 and the protrusion 2 may be manufactured separately and then grafted onto the substrate 3.

FIG. 2 shows an example in which the above-mentioned 1-polyte lens is applied to an optical fiber coupler. The two flat lenses 11 and 2I are arranged such that the two Fresnel lenses 14 and 24 formed on their respective substrates 13 and 23 are opposed to each other, and their respective projecting edges 12 and 22 are abutted and They are fixed to each other by suitable fixing means (not shown). An end of one optical fiber 5 is fixed to the center of the substrate 13 of one flat plate lens 11, and an end of the other optical fiber 6 is fixed to the center of the substrate 23 of the other 14-plate lens 21. - The optical fiber can be fixed to the substrate of the single-plate lens in various ways, but it is also possible to make an insertion hole in the substrate, insert the end of the optical fiber there, and fix it with adhesive, etc. A connector portion for fixing the optical fiber may be provided on the board.

The light propagating through one optical fiber 5 is emitted from its end face, becomes diverging light, passes through the transparent substrate 13 of one flat lens 11, and is collimated by the Fresnel lens 14. This parallel light propagates to the Fresnel lens 24 provided on the other flat lens 21 and is condensed by the Fresnel lens 24.

The light is incident on the end face of the other optical fiber 6.

FIG. 3 shows an example of the configuration of an optical system for obtaining an erect, same-magnification image. Three deck lenses 31° 41, 51 are provided, these flat lenses facing in the same direction. The ridge 42 of the second flat lens 41 is in close contact with the bottom surface of the first flat lens 31, and the ridge 52 of the third flat lens 51 is closely attached to the bottom surface of the second flat lens 41.

In a flat lens having such a laminated structure, an object 08 is placed at a distance of 1itLo in front of the first flat lens 31.
When placed, an erect equal-magnification image 01 with the same magnification as the object OR is formed at a position a distance L 1 behind the third flat lens 51.

In an optical system with such a laminated structure of plate lenses, the distance between the Fresnel lenses can be maintained accurately and constant depending on the thickness of each substrate and the thickness of each protrusion.
E i'/, the configuration of the optical system for the same magnification image is relatively easy. Furthermore, since a coupling member between flat lenses is not required, the optical system can be simplified and downsized.

Figure 4 shows an optical system that can obtain a royal equal magnification image by stacking three flat lenses 61, 71, 81 each with a plurality of Fresnel lenses 84, 74, 84 (H). JP-A-63-142319.

reference). In this way, a flat lens has multiple Fresnel lenses.
A lens can also be provided.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of a flat plate lens according to the present invention, Fig. 2 is a partially cutaway side view showing an example in which a single filter plate lens is applied to optical fiber coupling, and Fig. 3 is a perspective view showing an example of a planar lens according to the present invention. FIG. 3 is a partially cutaway side view showing an example in which a plate lens is applied to create a positive-y equal magnification image. FIG. 4 is a cross-sectional view showing an application example of a flat plate lens using an m-loss lens. Figure 2 1, 11. 2! , 31. 41. 51.
6+, 71. 81...Flat lens. 2, 12.22.32.42.52 ... ridge. 3, 13.23... Board. 4, 14.24.34.44.54.64.74.8
4... Fresnel lens. that's all

Claims (1)

[Claims] A flat plate lens in which at least one lens is formed on a flat plate-like substrate, characterized in that a protrusion that protrudes beyond the lens forming part is provided at at least one location on the substrate other than the lens forming part. Flat lens.