JPH11216761A - Microlens array manufacturing method, roll mold and indenter pressing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the formation of micro lens surfaces over a wide range without necessitating a large scale device by a method wherein a plurality of dented shapes of a roll mold, which is formed by forming a plurality of dents on the surface of the matrix of a cylindrical mold, are transferred to an optical member. SOLUTION: On the cylindrical surface of a mold matrix, a large number of dents are formed at the predetermined pitches spirally with high accuracy so as to form a pair of roll molds 15a and 15b, each having a cylindrical surface, on which a large number of dents corresponding to a large number of micro lens surfaces. The roll molds 15a and 15b are rotatably supported about center axis lines in the predetermined space. A sheet-like molten resin 16 is guided from an extruder 17 between the roll molds 15a and 15b and is cooled and solidified after being extruded. On the top surface and the under surface of the extruded resin sheet 16, a large number of micro lens surfaces are formed by the large number of dented shapes of the roll molds 15a and 15b through transferring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a microlens array, a roll mold suitable for carrying out the method, and an indenter pressing device suitable for molding the roll mold. is there.

[0002]

2. Description of the Related Art Conventionally, there is a reticle used in a single-lens reflex camera or the like in which a microlens array comprising a large number of microlenses arranged in a matrix is formed. This type of reticle is manufactured by injection molding, compression molding, or the like, using a mold having an inverted shape of a large number of microlens surfaces of a microlens array formed on a cavity surface and a suitable resin material. As a method of forming the inverted shape of the microlens array on the mold cavity surface,
There are an etching method and an indentation method. Japanese Patent Application Laid-Open No. 9-327860 filed by the present applicant discloses a method of manufacturing a microlens array using a mold formed by an indentation method.

FIG. 4 is a perspective view schematically showing a configuration of an indenter pressing device used in a conventional method of manufacturing a microlens array disclosed in Japanese Patent Application Laid-Open No. 9-327860. An indenter pressing device shown in FIG. 4 includes an XY stage 42 that holds a mold base material 41 and is movable along an XY plane.
And a moving coil 44 fixed to the support 43. The moving coil 44 has a shaft (not shown) that reciprocates in the Z direction, and an indenter 45 is attached to a tip of the shaft. The XY stage 42 and the moving coil 44 are electrically controlled by a control unit 46 such as a computer.

In the indenter pressing device shown in FIG. 4, while moving the XY stage 42 two-dimensionally in accordance with a command from the control unit 46, the moving coil 44 moves the indenter 45 in the Z direction.
Reciprocate periodically in the direction. Thus, the mold base material 4
A large number of indentations, that is, inverted shapes of the microlens array are formed in a predetermined range of one cavity surface.

[0005]

In the prior art as described above, when manufacturing a microlens array in which minute lens surfaces are formed over a wide range, the cavity surface of a mold base material is formed over a wide range. X to form an indent
It is necessary to largely move the Y stage two-dimensionally.
As a result, there is a disadvantage that the XY stage, and consequently the entire indenter pressing device, becomes large and expensive. Further, there is also a disadvantage that it takes a lot of time to form a large number of indentations and form a required mold.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is intended to manufacture a microlens array having a microlens surface formed over a wide range without requiring a large-sized device. An object of the present invention is to provide a method for manufacturing a lens array, a roll mold suitable for performing the manufacturing method, and an indenter pressing device suitable for molding the roll mold.

[0007]

According to the present invention, there is provided a method of manufacturing a microlens array having a plurality of minute lens surfaces, wherein a plurality of indentations are formed on the surface of a cylindrical mold base material. Forming a plurality of microlens surfaces by transferring a shape of the plurality of indentations of the roll mold to an optical member. provide. In this case, by rotating the roll mold on the optical member while bringing the surface of the optical member and the cylindrical surface of the roll mold into contact with a predetermined pressure, the cylindrical surface of the roll mold is It is preferable that the shapes of the plurality of indentations formed be transferred to the surface of the optical member. Further, by extruding the optical member from between the cylindrical surface of the roll mold rotatably supported around the central axis and the cylindrical surface of a predetermined roll member rotatably supported around the central axis, Preferably, the shapes of the plurality of indentations formed on the cylindrical surface of the roll mold are transferred to the surface of the optical member.

According to another aspect of the present invention, there is provided a roll mold having a cylindrical surface on which a plurality of minute curved surfaces corresponding to a plurality of minute lens surfaces of a micro lens array to be manufactured, The multiple small curved surfaces of the roll mold
A roll mold comprising a plurality of indentations formed by pressing an indenter having a tip portion having a shape corresponding to the minute curved surface against a cylindrical surface of a mold base material having a cylindrical shape as a whole. I will provide a.

Further, according to another aspect of the present invention, a mold base material having a cylindrical shape as a whole is held, and the mold base material is rotated about a center axis of the mold base material as a rotation axis. Holding the indenter having a tip having a shape corresponding to the shape of the indentation to be formed on the cylindrical surface of the mold base, and pressing the tip of the indenter against the cylindrical surface of the mold base. The indenter driving means for reciprocatingly driving the indenter along a predetermined axis, and the mold base material held by the rotary stage and the indenter held by the indenter driving means. Relative movement means for relatively moving along the center axis of the base material, the tip of the indenter while rotating the mold base material and relatively moving the mold base material and the indenter. Press against the cylindrical surface of the mold base material It allows to provide an indenter pressing device, which comprises forming a roll mold having a plurality of cylindrical surfaces which indentations are formed corresponding to the plurality of micro lenses surface of the microlens array to be manufactured. in this case,
The indenter driving means reciprocates the indenter along an axis perpendicular to the center axis of the mold base material, and the relative moving means holds the rotary stage and holds the center axis of the mold base material. It is preferable that the moving stage is configured to be two-dimensionally movable in a predetermined plane including a center axis of the mold base material.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a cylindrical surface (a surface corresponding to a side surface of a cylinder in a cylinder) of a mold base material having a cylindrical shape as a whole (a concept including a hollow cylindrical shape and a solid cylindrical shape) is used. A roll mold is formed by forming a plurality of indentations. Then, a microlens array having a plurality of microlens surfaces is manufactured by transferring the shapes of the plurality of indentations formed on the cylindrical surface of the formed roll mold to the optical member. In the present invention, the indenter pressing device of the present invention can be used for forming a roll die.

In the indenter pressing apparatus of the present invention, an indenter having a cylindrical shape as a whole and an indenter having a tip having a shape corresponding to the shape of the indentation to be formed on the cylindrical surface is formed by the indentation method. Form a roll mold. In particular,
While rotating the mold base material around its center axis as a rotation axis, while moving the mold base material and the indenter relatively along the center axis of the mold base material, for example, perpendicular to the center axis of the mold base material The tip of the indenter is periodically pressed against the cylindrical surface of the mold base material along the intersecting axis. Thus, a roll mold having a cylindrical surface on which a plurality of indentations corresponding to a plurality of microlens surfaces of a microlens array to be manufactured is formed.

As described above, in the present invention, a microlens array is manufactured using a roll die formed by the indentation method. Therefore, when manufacturing a microlens array in which a microlens surface is formed over a wide range, it is necessary to move the mold base material two-dimensionally over the same range as the microlens surface formation range. Unlike this, it is only necessary to move the mold base material one-dimensionally while rotating it. In other words, in the present invention, it is not necessary to largely control the drive of the XY stage two-dimensionally in a plane when the roll mold is formed. Therefore, according to the present invention, it is possible to manufacture a microlens array in which minute lens surfaces are formed over a wide range without requiring a large-sized device. Also, in the present invention, if the micro-lens array is manufactured by rotating the roll mold by one or more rotations, it is only necessary to form indentations smaller in number than the number of micro-lens surfaces of the micro-lens array to be manufactured. A mold can be formed, and as a result, a microlens array having a large number of microlens surfaces can be rapidly manufactured.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing a configuration of an indenter pressing device for forming a roll die used in a method of manufacturing a microlens array according to an embodiment of the present invention. In the indenter pressing device shown in FIG. 1, a moving stage 2 that can move two-dimensionally along an XY plane is fixed on a surface plate 1. The moving mechanism of the moving stage 2 includes, for example, a linear guide, a feed screw, a motor as driving means,
It consists of an encoder. In this case, the position of the moving stage 2 can be accurately controlled by using a stepping motor or a servomotor as the motor.

A rotary stage 4 is provided on the moving stage 2 via a support member 3. Rotary stage 4
Holds a cylindrical mold base material 5 to be subjected to indentation processing via a holding member (dedicated hire) 6, and holds the held mold base material 5.
Is rotated about its central axis (in FIG. 1, an axis parallel to the X axis). The rotating mechanism of the rotating stage 4 is composed of, for example, a bearing and a stepping motor as a driving unit. In addition, as a material of the mold base material 5, a copper alloy, a martensitic stainless steel alloy, or the like can be used.

Referring again to FIG. 1, the column 9 is a platen 1
The indenter driving section 8 is supported on the column 9. The indenter driving unit 8 holds the indenter 7 having a tip portion having a shape corresponding to the shape of the indentation to be formed on the cylindrical surface of the mold base material 5, and is positioned at a predetermined position with respect to the mold base material 5. In the machined state, a mechanism is provided for periodically driving the indenter 7 back and forth along an axis perpendicular to the central axis of the mold base material 5. As a driving mechanism of the indenter driving unit 8, a moving coil or a piezo element that can electrically control the oscillation period can be used. When a moving coil is used for the drive mechanism of the indenter drive unit 8, the moving coil has a shaft that reciprocates in a predetermined direction, and the indenter 7 is attached to the tip of this shaft.

As a method of attaching the indenter 7 to the indenter driving section 8, for example, fastening with a screw or gripping with a chuck can be used. Further, as a material of the indenter 7, for example, diamond, cemented carbide, or the like can be used. The moving stage 2, the rotating stage 4, and the indenter driving unit 8 are electrically controlled by a control unit 10 such as a computer. Also, in FIG. 1, for clarity of illustration, the indenter driving unit 8 is drawn so as to drive the indenter 7 along the Z-axis direction, but intersects perpendicularly with the center axis of the mold base material 5. The direction of the indenter drive unit 8 can be appropriately set so as to reciprocately drive the indenter 7 along an arbitrary axis.

When indenting the mold base material 5 on the cylindrical surface, the moving stage 2 is finely moved in the Y-axis direction so that the center axis of the mold base material 5 and the drive axis of the indenter 7 intersect. . The indenter 7 is periodically reciprocated by the indenter driving unit 8 in accordance with a command from the control unit 10, and the moving stage 2 is driven in the X-axis direction in synchronization with the oscillation cycle of the indenter driving unit 8, and the rotating stage is rotated. 4 is rotationally driven.
As a result, a large number of indentations are spirally formed at a predetermined pitch on the cylindrical surface of the mold base material 5 with high precision. In this manner, a roll mold having a cylindrical surface on which a number of indentations corresponding to a number of microlens surfaces of a microlens array to be manufactured is formed.

For example, when indentation is performed at a pitch of 20 μm ± 1 μm on a cylindrical surface of a mold base material 5 having an outer diameter of 50 mm, if the vibration frequency of the indenter driving unit 8 is 20 Hz, the rotation speed of the rotary stage 4 Is about 0.15 rpm, and the moving speed of the moving stage 2 in the X direction is about 0.26 μm / mi.
n. That is, the feed speed of the moving stage 2 and the rotation speed of the rotary stage 4 are set to extremely low speeds. Further, by setting the indentation speed by the indenter driving unit 8 which is an indentation vibration unit to be sufficiently higher than the rotation speed of the rotary stage 4 and the moving speed of the moving stage 2, the rotating stage 4 and the moving stage 2 are pitched during indentation processing. It is possible to continuously drive at a constant speed without feeding.

Next, a method of manufacturing a microlens array using a roll mold formed by the indenter pressing device of FIG. 1 will be described. FIG. 2 is a diagram illustrating a method of manufacturing a microlens array by an extrusion method using a pair of roll dies. In FIG. 2, a pair of roll dies 15a and 15b formed according to the present invention are rotatably supported around a central axis, and a predetermined space is formed between the roll dies 15a and 15b. An extruder 17 is provided on the left side of the pair of roll dies 15a and 15b in the drawing, and an appropriate sheet-like molten resin 16 is supplied from the extruder 17. The sheet-like molten resin 16 supplied from the extruder 17 is supplied to a roll mold 15a.
After being guided between the roll dies 15a and 15b and extruded from between the roll dies 15a and 15b, it is cooled and solidified.

As described above, a large number of indentations are formed on the cylindrical surfaces of the roll dies 15a and 15b corresponding to a large number of microlens surfaces of the microlens array to be manufactured. Therefore, the upper and lower surfaces of the resin sheet extruded from between the roll dies 15a and 15b have
Roll dies 15a and 1 by so-called embossing
The shape of the many impressions of 5b is transferred, and the many micro lens surfaces of the micro lens array to be manufactured are formed. That is, a desired microlens array can be formed on the upper surface and the lower surface of the resin sheet by cutting the resin sheet that has been extruded from between the roll dies 15a and 15b and then solidified according to predetermined dimensions. By using a roll member having a smooth cylindrical surface instead of one roll mold, the microlens array can be formed only on one side of the resin sheet.

FIG. 3 is a view for explaining a method of manufacturing a microlens array on the surface of the resin sheet by rotating a roll die on the surface of the resin sheet. In FIG. 3, the roll mold 19 is rotated on the surface of the resin sheet 18 such that the resin sheet 18 whose surface is heated to a temperature equal to or higher than the softening temperature and the cylindrical surface of the roll mold 19 are brought into contact with a predetermined pressure. After the movement, the resin sheet 18 is cooled. On the cylindrical surface of the roll mold 19, a number of indentations corresponding to a number of microlens surfaces of the microlens array to be manufactured are formed. Therefore, the resin sheet 18 in contact with the cylindrical surface of the roll mold 19 at a predetermined pressure.
Roll mold 1 by so-called embossing
Nine indentations are transferred to form numerous microlens surfaces of the microlens array to be manufactured.

As described above, in this embodiment, the microlens array is manufactured using the roll mold formed by the indentation method in the apparatus shown in FIG. Therefore, when manufacturing a microlens array having a large number of microlens surfaces formed over a wide range, it is necessary to two-dimensionally move the mold base material over the same range as the microlens surface formation range. Unlike the related art, it is only necessary to move the mold base material one-dimensionally while rotating it, and it is not necessary to largely control the drive of the XY stage two-dimensionally in a plane. In addition, if the micro-lens array is manufactured by rotating the roll die one or more times, the die can be formed by forming only a small number of indentations less than the number of micro-lens surfaces of the micro-lens array to be manufactured. can do. Therefore, in this embodiment, without the need for a large device,
A microlens array having a large number of microlens surfaces formed over a wide range can be manufactured quickly.

In the indenter pressing device shown in FIG. 1, the support member 3 and the holding member 6 are changed as required to make the rotary shaft of the rotary stage 4 stand upright (set along the Z-axis direction), thereby obtaining a circular shape. Indentations can be formed on the surface of the flat mold base material. Also, for the conical mold base material, the supporting member 3 and the holding member 6 are set in accordance with the angle of the cone.
In addition, it is possible to cope by adding necessary changes to the rotating stage 4.

Further, in the indenter pressing device shown in FIG. 1, the rotation axis of the rotary stage 4 is set upright, and the outer diameter (50
mm), when the same indentation processing as in the numerical example is spirally performed on the surface of the circular flat plate-shaped mold base material, the speed setting of each stage in the outer peripheral indentation processing is the same as the numerical example. If this processing is performed only on the XY stage according to the prior art, X
Not only does the control of the Y stage become complicated, but it becomes very difficult to perform the indentation processing with the accuracy described above due to backlash or the like generated when the feed mechanism of the XY stage rotates in the forward or reverse direction.

In the indenter pressing device shown in FIG. 1, the moving stage 2 is configured to be movable two-dimensionally in the XY plane, and when the indentation is processed, the moving stage 2 is driven in the X-axis direction. The moving stage 2 is driven in the Y-axis direction when adjusting with the center axis of the mold base material 5. However, the moving stage 2 can be configured to be movable only in the X-axis direction. In this case, an adjusting mechanism for adjusting the drive axis of the indenter 7 so that the center axis of the mold base material 5 intersects is required. Incidentally, the present invention is a convex lens,
The present invention is applicable to the manufacture of a microlens array in which a plurality of microlenses such as a concave lens and a prism are arranged.

[0026]

As described above, according to the present invention,
Since a microlens array is manufactured using a roll mold formed by an indentation method, a microlens array having a large number of microlens surfaces formed over a wide area can be quickly formed without requiring a large-sized device. Can be manufactured.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a configuration of an indenter pressing device for molding a roll die used in a method of manufacturing a microlens array according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a method of manufacturing a microlens array by an extrusion method using a pair of roll dies.

FIG. 3 is a diagram illustrating a method of manufacturing a microlens array on the surface of a resin sheet by rotating a roll die on the surface of the resin sheet.

FIG. 4 is a perspective view schematically showing a configuration of an indenter pressing device used in a conventional microlens array manufacturing method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 surface plate 2 moving stage 3 support member 4 rotation stage 5 mold base material 6 holding member 7 indenter 8 indenter drive unit 9 column 10 control unit 15 roll mold 16 molten resin 17 extruder 18 resin sheet 19 roll mold 41 mold Mold base material 42 XY stage 44 Moving coil 45 Indenter 46 Control unit

Claims (4)

[Claims] 1. A method of manufacturing a microlens array having a plurality of microlens surfaces, wherein a roll mold is formed by forming a plurality of indentations on the surface of a cylindrical mold base material; A method of manufacturing a microlens array, wherein the plurality of microlens surfaces are formed by transferring shapes of a plurality of indentations to an optical member. 2. The roll mold cylinder is rotated by rotating the roll mold on the optical member while bringing the surface of the optical member into contact with the cylindrical surface of the roll mold at a predetermined pressure. The method according to claim 1, wherein the shapes of the plurality of indentations formed on the surface are transferred to the surface of the optical member. 3. A roll mold having a cylindrical surface on which a plurality of minute curved surfaces corresponding to a plurality of minute lens surfaces of a micro lens array to be manufactured, wherein the plurality of minute curved surfaces of the roll mold are: A roll mold comprising a plurality of indentations formed by pressing an indenter having a tip portion having a shape corresponding to the minute curved surface against a cylindrical surface of a mold base material having a cylindrical shape as a whole. . 4. A rotating stage for holding a mold base material having a cylindrical shape as a whole and rotating the mold base material around a central axis of the mold base material as a rotation axis; Holding an indenter having a tip having a shape corresponding to the shape of an indentation to be formed on the cylindrical surface, and pressing the tip of the indenter against the cylindrical surface of the mold base along a predetermined axis to press the tip of the indenter against the cylindrical surface of the mold base material. Indenter driving means for reciprocatingly driving the indenter; and relative movement of the mold base material held by the rotary stage and the indenter held by the indenter driving means along a central axis of the mold base material. A relative moving means for causing the tip of the indenter to press against the cylindrical surface of the mold base while rotating the mold base and moving the mold base and the indenter relative to each other. Microphones to be manufactured by An indenter pressing device characterized by forming a roll mold having a cylindrical surface on which a plurality of indentations corresponding to a plurality of microlens surfaces of a lens array are formed.