JPH04190301A - Manufacture of plate lens array - Google Patents

Abstract

PURPOSE:To facilitate with high accuracy manufacturing of a plate lens array with dense packed structure by performing the coating process in two stages by combining a non-wet type mask and consistent liquid. CONSTITUTION:In the first coating process, the surface of a substrate 1 is coated by means of a mask member 2 which consists of the liquid resistant non-wet type material which is provided with a group of openings 2A of the desired lens arrangement pattern, then the consistent liquid which turns transparent after solidification is coated on this surface. The mask member is removed, and the material 4 which turns transparent after solidification is applied or coated on this surface, and the convex surfaces are expanded in the radial direction by making lamination onto the lens convex surfaces 3 obtained in the first process, and the flat surface parts between the lenses which still remain after completion of the first process are reduced. This constitution allows the plate lens array of the dense packed arrangement where it is difficult to manufacture the plate lens array by the press-molding since the substrate is thin and the respective lens sizes are very small to be manufactured easily with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a flat lens array in which a large number of microlenses are densely arranged on a flat substrate.

[Conventional technology]

One of the uses of flat lens arrays is to use them in combination with solid-state imaging devices, liquid crystal panels, etc., thereby significantly increasing the amount of light received or transmitted by these devices.

For example, by placing microlenses facing each pixel of a liquid crystal panel, illumination light is focused by each microlens, and light that would normally enter the pixel wiring section or pixel transistor and be blocked is also removed. The purpose is to make the liquid crystal display brighter by effectively directing the light into the liquid crystal aperture window.

In flat lens arrays used for such applications, if there is a non-lens part on the λ lens base material surface, the incident light will be
0% light is not collected, and the light collection efficiency is reduced by the area of the non-lens portion. Therefore, it is preferable that the planar lens array used for the above-mentioned applications has a close-packed structure in which the outer shape of each lens is polygonal in plan view, and the lenses are in close contact with each other using the ridge lines as boundaries.

The present invention aims to provide a method for easily manufacturing such a flat lens array with a densely packed structure.

An example of a flat lens manufacturing method that has been proposed in the past is JP-A-52-27647.

The method disclosed in the above-mentioned document covers the surface of a transparent substrate with a non-wetting mask having a group of openings in a desired array pattern, and coats this surface with a viscous liquid that can solidify into a transparent material. , 20 Forming a viscous liquid film with a convex spherical or convex cylindrical surface on the base material surface exposed at the mask opening due to the surface tension of the viscous liquid itself, and then solidifying the viscous liquid. This is a method of making a lens array by combining the two.

[Problem that the invention seeks to solve]

However, in the conventional manufacturing method described above, the portion of the mask material placed on the surface of the lens base material other than the openings becomes a non-lens portion, and there is a serious problem that a flat lens array with a densely packed structure cannot be manufactured. .

[Means for solving problems]

The method of the present invention is similar to the conventional method described above in that it uses a combination of a non-wetting mask material and a viscous liquid, but
In order to solve the problems of the conventional method, the coating process is divided into two stages as follows.

The first coating step in the method of the present invention is the same as in the conventional method (
, the substrate surface is covered with a mask material made of a material that is non-wetting to liquids and has aperture groups with a desired lens arrangement pattern, and a viscous liquid that solidifies into a transparent material is applied to this surface. .

The diameter of the lens obtained after this first step is approximately the same as the aperture diameter of the mask.

Next, after removing the mask material, a material that solidifies to become a transparent body is applied or formed into a film, and is laminated onto the convex surface of the lens obtained in the first step to enlarge the convex curved surface in the radial direction. After completing one step, the remaining interlens plane portion is eliminated.

The coating material used in the second coating step described above does not necessarily have to be a viscous liquid.

A thick film of a substance such as Si or SiO□ may be formed.

In this specification, film formation in a broad sense, including film formation by particle deposition such as vapor deposition and sputtering, is referred to as "coating."

The thickness of the material applied in this second coating step must be such that, at the minimum, the flat parts remaining between the lenses after the first step are filled with the curved surfaces of the laminated film to form a densely packed structure. Further values are determined by the intended radius of lens curvature.

[For production]

According to the method described above, a film is laminated in the second coating process on the lens convex part formed in the first coating process, and the lens convex part is enlarged while maintaining its curved shape in cross section. Finally, a lens array in which adjacent lenses and convex portions are in close contact with each other is obtained.

In addition, in the second coating step, if a material with excellent weather resistance such as SiO□ is coated, this film also functions as a protective film.

〔Example〕

EMBODIMENT OF THE INVENTION Below, one embodiment of the present invention shown in the drawings will be described in detail.

First, as shown in FIG. 1A, one side of a transparent substrate is covered with a mask material 2 made of a non-uniform material in which a large number of openings 2A are formed at regular intervals in a desired lens arrangement pattern.

To give a numerical example, the glass substrate 1 is 100W square with a thickness of 1. The mask material 2 is a nickel sheet with a thickness of about 50 μm in which circular openings 2A each having a diameter of 50 μm are arranged in a staggered manner with a center-to-center distance of 70 μm. The glass substrate 1 with the mask material 2 adhered in this way is set above the evaporation source in a vacuum evaporation apparatus with the mask material side facing downward.

Next, after evacuating the inside of the apparatus to a vacuum level of about 10-'Tart, a material made of soda lime glass flakes is used as an evaporation source, and it is irradiated with an electron beam (for example, 4' Oe V) to evaporate it. and evaporate onto the glass substrate 1 via the mask material 2.

This first step of vapor deposition is carried out for about 30 minutes in the numerical example.

After that, stop the electro beam and leave it for 2 hours.
As shown in the same figure (b), the liquid glass adhering to the substrate surface in the mask material opening 2A is surrounded by a non-wetting wall, so it bulges into a convex spherical shape due to surface tension and solidifies. Microlens nuclei 3 are formed.

Next, the mask material 2 is removed from the substrate 1, the vapor deposition source is changed from soda lime glass to quartz, and a second stage vapor deposition process is performed for about 50 minutes in the same manner as the first stage vapor deposition.

Through this second stage vapor deposition process, the transparent film 4 is gradually laminated on each lens nucleus 3 and the substrate surface between them, as shown by the dotted line in FIG. As a result of the enlargement, a close-packed lens array 5 is finally formed in which the curved surfaces of adjacent lenses are successively arranged one after another without a flat part between them.

The individual lenses 5A forming this lens array 5 are made of a mask material 2 having an open pattern arranged in a staggered manner at equal intervals as described above.
When this lens is used, it becomes a substantially regular hexagon in plan view, and a honeycomb-shaped lens array is obtained in which the regular hexagonal lens groups are in contact with each other with the ridge line as the boundary.

The coating substance used in the method of the present invention may be a resin material other than glass in the first coating step, as long as it is a viscous liquid that can solidify at a relatively low melting point to become a transparent body.
There are no particular restrictions on the material. Further, since the coating material used in the second stage coating process forms the outer surface of the lens array, it is desirable to use a transparent material with good weather resistance such as quartz, but it may be the same as the first stage coating material.

〔Effect of the invention〕

According to the present invention, it is possible to easily manufacture with high precision a densely packed planar lens array in which the substrate thickness is thin and the individual lenses are very small in size, which is difficult to manufacture by press molding. I can do it.

[Brief explanation of drawings]

FIGS. 1(a) to 1(c) show an embodiment of the present invention step by step; FIG. 1(a) is a sectional view showing the process of disposing a non-wetting mask material on the substrate surface; FIG. 1(b) is a sectional view showing the same side. A cross-sectional view showing the process of forming a lens nucleus by applying a viscous liquid and solidifying it. ()\) shows a lens with a densely packed array by performing the second coating after removing the mask material. FIG. 3 is a cross-sectional view showing the process of forming an array. ■...Glass substrate, 2...Non-wetting mask material, 2A.
...Aperture, 3...Lens nucleus, 4...Transparent film, 5.
...Densely packed lens array. Patent applicant Nippon Sheet Glass Co., Ltd. Figure 1

Claims (1)

[Claims] By covering the surface of the transparent substrate with a mask material made of a material that is non-wetting to liquid and having a large number of openings in a desired lens arrangement pattern, and applying a viscous liquid to this surface and solidifying it, forming a convex spherical lens nucleus on the substrate surface of the mask opening by surface tension, and after removing the mask material, applying a transparent coating to this surface so that the curved protrusion of the lens nucleus is maintained and is adjacent to the substrate surface; and applying the coating to a thickness such that there are no flat areas between the protrusions.