JP2541584B2 - Microlens array manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a microlens array used in an optical device for optical communication or the like, for the purpose of preventing distortion of the lens shape that occurs when forming a one-dimensional lens array, When a film containing a photoreactive substance is locally irradiated with light and the concentration of the photoreactive substance or the concentration of the substance generated from the photoreactive substance changes, the photoreactive substance migrates to generate light. In the method of producing a one-dimensional microlens array by using the phenomenon that the volume of the irradiated portion increases, the excessive movement of the photoreactive substance near the array is suppressed,
It is configured by providing a photoreactive substance absorption region that suppresses distortion of the lens shape.

[Industrial applications]

The present invention relates to a method for manufacturing a microlens array used in an optical device for optical communication or the like.

Plastic lenses are required to be arrayed and miniaturized such as application to branching, coupling, multiplexing, and demultiplexing of light in optical fiber communication, light emitting diode focusing in optical integrated circuits, and application to waveguide lenses. There is. Therefore, a method of manufacturing a lens array of a thick film distribution film, which is easy to form an array and is inexpensive, has been developed.

[Conventional technology]

A conventional lens array manufacturing method using a film thickness distribution film is
First, as shown in FIG. 2A, a film 2 containing a photoreactive substance such as cinnamic acid, cholesterol cinnamate, vinyl cinnamate, etc. is formed on a substrate 1, and the windows 3 are arrayed on the film 2. By exposing using the mask 4 provided, a photoreaction product is generated in the light-irradiated portion, and the photoreactive substance moves from the light-unirradiated portion to the light-irradiated portion due to the permeation phenomenon. As shown in FIG.
Is formed.

[Problems to be solved by the invention]

In the conventional method of manufacturing a lens array described above, in the case of manufacturing a one-dimensional microlens array as shown in FIG. 3, if a mask having circular windows arranged in a row is used, the direction of the array and the direction perpendicular thereto are The amount of substances that move in the membrane is different (the array direction is small and the vertical direction is large). Further, in the unexposed region between adjacent lenses, the transfer substance is depleted to form a hard film, and the lens diameter is difficult to spread in the array direction, and conversely, the concentration of the transfer substance is high in the vertical direction and the lens diameter tends to spread. There is a problem that the lens 5 formed by these factors has an elliptical shape extending in a direction perpendicular to the array.

In view of the above problems, it is an object of the present invention to provide a method for manufacturing a microlens array that prevents distortion of the lens shape that occurs when forming a one-dimensional lens array.

[Means for solving problems]

The above-mentioned object is to locally irradiate a film containing at least the photoreactive substance M with light to change the concentration of the photoreactive substance M or the concentration of the substance M ′ produced from the photoreactive substance. In the method for producing a one-dimensional microlens array by using the phenomenon that the photoreactive substance M moves due to the increase in the volume of the light-irradiated portion, the excessive movement of the photoreactive substance M is suppressed beside the array. This is achieved by a method for manufacturing a microlens array, which is provided with a photoreactive substance absorption region 16 that suppresses distortion of the lens shape.

[Work]

By providing the photo-reactive substance absorption region 16 beside the array, it is possible to prevent the photo-reactive substance from excessively moving from the vertical direction of the array toward the lens, thereby preventing the lens shape distortion. It becomes possible to do.

〔Example〕

FIG. 1 is a view showing an embodiment of the present invention, in which a is a mask b is a microlens array.

As shown in FIG. 1A, the mask 10 used in the method for manufacturing the microlens array of this embodiment has a plurality of holes 11 for irradiating the lens portion arranged in a straight line, and the hole reactivity in the vicinity thereof. Holes for irradiating areas that absorb substances
12 are formed.

In this embodiment, the mask 10 is used to expose the film 13 containing the photoreactive substance M shown in FIG. In the film 13 thus exposed, the photo-reactive substance M in the light-irradiated portion becomes the photo-reaction product M ', so that the photo-reactive substance is irradiated as shown by the arrow from the non-irradiated portion due to the permeation phenomenon. Move to the irradiation area. As a result, the volume of the light-irradiated portion increases and a microlens array 15 in which a large number of lenses 14 are arranged in a straight line is formed. At this time, the photoreactive substance absorption region 16 is formed in the portion of the mask 10 which is irradiated with the light by the hole 12. Since the photo-reactive substance absorption region 16 absorbs the excess photo-reactive substance toward the lens 14, the lens 14 is prevented from spreading in the vertical direction of the array 15 and a lens with less distortion is formed.

As an example according to the method of this example, a film containing cinnamyl cinnamate as a photoreactive substance and polymethylmethacrylate (PMMA) as a binder, a lens diameter of 100 μm, and a pitch of 125 μm
m, the diameter of the absorption region 16 was 50 μm, and the center distance between the lens 14 and the absorption region 16 was 125 μm, when a microlens array was formed, there was almost no vertical expansion of the array.

〔The invention's effect〕

As described above, according to the present invention, the exposure region (photoreactive substance absorption region) that suppresses the movement of the excessive photoreactive substance is provided beside the microlens array, so that the array spreads in the vertical direction. It is possible to provide a microlens array that can be suppressed and has no distortion in the lens shape.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention, FIG. 2 is a diagram for explaining a conventional method for producing a lens array of a film thickness distribution film, and FIG. 3 is a problem to be solved by the invention. Explain the points. In the figure, 10 is a mask, 11 is a hole for irradiating a lens portion, 12 is a hole for irradiating a photoreactive substance absorption region, 13 is a film containing a photoreactive substance, 14 is a lens, 15 is a microlens array, and 16 is a microlens array. The photoreactive substance absorption region is shown.

Claims (1)

(57) [Claims] 1. A film containing at least a photoreactive substance (M) is locally irradiated with light to obtain a concentration of the photoreactive substance (M) or a substance (M ') produced from the photoreactive substance. In the method for producing a one-dimensional microlens array by using the phenomenon that the photoreactive substance (M) moves and the volume of the light-irradiated portion increases due to the change in the concentration of A method for producing a microlens array, comprising a photoreactive substance absorption region (16) for suppressing excessive movement of a substance (M) and suppressing distortion of a lens shape.