JP2003098313A - Aspheric lens array, method for manufacturing die and method for manufacturing aspheric lens array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aspheric lens array in which the curved face of each lens is aspheric, to provide a method for manufacturing a die to manufacture the die for molding the aspheric lens array, and to provide a method for manufacturing the aspheric lens array, by which the aspheric lens array is molded by using the die. SOLUTION: In the aspheric lens array 51, the curved face of each lens is aspheric and the focuses of the lenses are aligned on one straight line or on one plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aspherical lens array in which the curved surface of each lens is an aspherical surface, a mold manufacturing method for manufacturing a mold for molding this aspherical lens array, and this mold. The present invention relates to a method for manufacturing an aspherical lens array, which is used to mold an aspherical lens array.

[0002]

2. Description of the Related Art Usually, in lenses and lens arrays, the curved surfaces of the lenses are spherical. However, even if the curved surface of the lens is a spherical surface, it is not possible to form an image at the focal point due to spherical aberration, chromatic aberration, etc. Aspherical spherical lenses have been developed and used.

This aspherical lens can be manufactured by cutting and polishing a lens base material based on the designed aspherical shape.

[0004]

As described above, although a single aspherical lens can be manufactured, an aspherical lens array in which aspherical lenses are arranged is limited by the technology of manufacturing a mold. It could not be manufactured. However, since the aspherical lens array has various uses and is highly useful, a mold for molding the aspherical lens array is desired.

The present invention has been made in order to meet the above-mentioned demand, and an aspherical lens array in which the curved surface of each lens is an aspherical surface, and a mold for manufacturing a mold for molding this aspherical lens array. Provided are a method and a method for manufacturing an aspherical lens array in which an aspherical lens array is molded using this mold.

[0006]

In the aspherical lens array according to the present invention, the curved surface of each lens is an aspherical surface, and the focal point of each lens is located on the same straight line or the same plane. Next, the manufacturing method of the mold according to the present invention,
Place a plurality of semicircles on a straight line, and place a mask between the semicircles and the left and right of the semicircles on the resist as transparent parts.
Set the mask so that the exposure time for forming the curved surface of the aspherical lens forming the aspherical lens array is such that the apex of the semicircle is from the upper end of each aspherical lens to the lower end of each aspherical lens. From the lower end of each non-curved lens to the upper end of each non-curved lens until the apex is reached, from the left end of each non-curved lens to the right end of each non-curved lens until the apex of the semicircle reaches the apex of each aspherical lens. Direction until the apex of the semicircle reaches the apex of each aspherical lens, from the right end of each aspherical lens to the left end of each aspherical lens until the apex of the semicircle reaches the apex of each aspherical lens. The resist is exposed by X-ray lithography by moving in order, and at least a female mold of a mold for manufacturing an aspherical lens array is manufactured by plating based on a master mold developed with this resist. Then, it is desirable that the metal used to manufacture the mold is a metal having a linear expansion coefficient similar to that of nickel. Next, in the method of manufacturing the aspherical lens array according to the present invention, the mold manufactured as described above is used, and the aspherical lens array is molded by using resin or glass as a molding material. Then, the metal used to manufacture the mold is a metal having a linear expansion coefficient similar to that of nickel, and the melting point is 350 ° C to 450 ° C.
It is desirable to mold the aspherical lens array using the above glass, or to mold the aspherical lens array using glass having a coefficient of linear expansion similar to that of nickel.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing a mask used in the mold manufacturing method of the present invention.

In FIG. 1, the mask 11 is, for example, 25.
For example, gold (Au) is used as the X-ray absorption film 13 on the membrane material 12 made of a polyimide film having a thickness of 2.5 μm.
It is patterned with a thickness of μm to 3.0 μm.

The X-ray absorption film 13 has a pattern in which the diameter of a semicircle 13a having a predetermined radius is located on a straight line so that the semicircles 13a are adjacent to each other.
p, first straight line portions 13q and 13q provided on the left and right sides of the semicircle 13a in which the semicircle 13a is arranged, and the first straight line portion 1
Second straight line portions 13r and 13r rising at a radius of the semicircle 13a at right angles from the ends of the semicircle 13a of 3q and 13q.
And the upper ends of the second straight line portions 13r, 13r are attached to the respective semicircles 13
The transparent portion 13b is surrounded by the third linear portion 13s connected so as to contact the apex of a.

FIG. 2 is a perspective view showing a resist and the like for manufacturing a mother die for manufacturing a die.

In FIG. 2, reference numeral 21 denotes a conductor substrate, 22 denotes a resist provided on the conductor substrate 22, for example, by sticking the resist 22. The resist 22 has a thickness of a radius of a semicircle 13a, for example. Now, it is a square in plan view that is slightly shorter than the third linear portion 13s of the transmissive portion 13b. As the resist 22, PMMA (polymethylmethacrylate), PTFE (polytetrafluoroethylene), or the like was used.

FIGS. 3 (a) and 3 (b) are explanatory views for forming the master mold of the spherical lens array and the master mold of the aspherical lens array on the resist, and FIG. 4 is the master mold of the spherical lens, and It is explanatory drawing for forming the mother die of a spherical lens, and attaches | subjects the same code | symbol to FIG. 1 or FIG. 2 or an equivalent part, and abbreviate | omits description.

In FIG. 3 or 4, reference numeral 22a denotes a spherical lens master block, which is formed by developing the exposed resist 22. Reference numeral 22b denotes an aspherical lens master block, which is formed by developing the exposed resist 22. Reference numeral 31A denotes a spherical lens array master block, and spherical lens master blocks 22a are formed in a matrix on one main surface. Reference numeral 31B indicates an aspherical lens array master block, and an aspherical lens master block 22b is formed in a matrix on one main surface.

Next, before describing the manufacture of the aspherical lens array master block 31B, the manufacture of the spherical lens array master block 31A will be described. First, as shown in FIG. 3A, the mask 11 is set at a predetermined position on the resist 22, and the mask 11 is moved from the upper side to the lower side in the spherical lens matrix 2 of the first row.
Since the upper side of 2a is mainly formed, a predetermined energy (the radius of the semicircle 13a can be exposed even if irradiation is continued so that the right half of the curve A forming the spherical surface shown in FIG. 4 is formed). The X-ray of (energy) is irradiated and the apex of the mask 11 is moved to the apex of the spherical lens master block 22a.

Then, the mask 11 is inverted and the semicircle 13
The mask 11 is set on the resist 22 at the position where the apex of a is the lower end of the spherical lens master block 22a of the first row, and the mask 11 is moved from the lower side to the upper side of the spherical lens master block 22 of the first row.
In order to mainly form the lower side of a, X-rays of predetermined energy are irradiated so that the left half of the curve A forming the spherical surface shown by the dotted line in FIG. Move to the top of the mold 22a.

After that, the above-described exposure of the spherical lens master block 22a of the first row is also performed on the second, third, and fourth rows. The spherical lens master blocks 22a of the first and second rows, the second and third rows, and the third and fourth rows are adjacent to each other.

Next, as shown in FIG. 3B, the semicircle 13
The mask 11 is set on the resist 22 at the position where the apex of a is the left end of the spherical lens master block 22a in the first column, and the mask 11 is moved from left to right in the spherical lens master block 22 in the first column.
In order to form mainly the left side of a, X-rays of predetermined energy are irradiated so that the left half of the curve A forming the spherical surface shown by the dotted line in FIG. Move to the top of 22a.

Further, the mask 11 is inverted so that the semicircle 13
The mask 11 is set on the resist 22 at the position where the apex of a is the right end of the spherical lens matrix 22a in the first column, and the mask 11 is moved from right to left in the spherical lens matrix 22 in the first column.
In order to mainly form the right side of a, X-rays of predetermined energy are irradiated so that the right half of the curve A forming the spherical surface shown by the dotted line in FIG. Move to the top of 22a.

After that, the above-mentioned exposure of the first-row spherical lens master block 22a is also performed on the second, third, and fourth columns.

After exposing the resist 22 as described above,
By developing, as shown in FIG. 3B, the spherical lens matrix 2 of the spherical lens of 4 rows and 4 columns is formed on the resist 22.
A spherical lens array matrix 31A having 2a can be obtained.

When the resist 22 is exposed as described above, the mask 11 is moved to expose the resist 22 so as to form a curve B forming an aspherical surface shown in FIG. 4 and then developed. As shown in FIG. 3B, it is possible to obtain the aspherical lens array matrix 31B having the aspherical lens matrix 22b of the aspherical lenses of 4 rows and 4 columns on the resist 22.

FIG. 5 is an explanatory view for manufacturing a mold for molding an aspherical lens array, FIG. 6 is an explanatory view for molding an aspherical lens array using the mold, and FIG. 7 is a perspective view showing the aspherical lens array. Therefore, the same or corresponding parts as those in FIGS.

In FIG. 5, reference numeral 42 denotes a female die which constitutes the die 41 for molding the aspherical lens array 31B shown in FIG. In FIG. 6, reference numeral 43 denotes a flat mold forming a mold 41 for molding the aspherical lens array 31B shown in FIG. In FIG. 7, reference numeral 51 indicates an aspherical lens array.

Next, the manufacture of the mold 41 will be described.
First, the production of the female die 42 will be described. As shown in FIG. 5, on the aspherical lens array mother die 31B side of the conductor substrate 21 on which the aspherical lens array mother die 31B manufactured as described above is placed. By growing a plating layer of platinum (Pt), for example, by electroplating, a female mold 42 that duplicates the aspherical lens array mother mold 31B can be manufactured.

As described above, when the female die 42 is manufactured by electroplating, a platinum metal layer is provided in advance on the portion to be plated by chemical plating or vapor deposition, and the aspherical lens matrix 22b is covered with the metal layer. , Electroplating on the metal layer, female mold 42
Since the electroplating isotropically grows on the metal layer when manufacturing, the surface accuracy of the surface of the female die 42 on which the aspherical lens array 51 is formed can be improved.

Then, by removing the aspherical lens array matrix 31B and the conductor substrate 21 from the female die 42, the female die 42 can be made as a single body. Next, the flat mold 43 is manufactured using the same metal as that used for electroplating, whereby the manufacture of the mold 41 for molding the aspherical lens array 51 is completed.

Next, the molding of the aspherical lens array 31B will be described. First, low-melting glass, for example, Vidron PG375 (trade name) manufactured by Sumita Optical Co., which has a melting point (molding temperature) of 370 ° C. to 375 ° C., or a melting point (molding temperature) of 4
K-PS50 (trade name) manufactured by Sumita Optical Co., Ltd. having a temperature of 10 ° C. to 415 ° C. or K-PSK100 (trade name) manufactured by Sumita Optical Co., Ltd. having a melting point (molding temperature) 420 ° C. to 425 ° C. or a melting point (molding temperature) K- manufactured by Sumita Optical Co., Ltd. at 440 ° C to 450 ° C
FIG. 6 shows a molten glass obtained by melting PSK11 (trade name).
As shown in FIG. 7, the aspherical lens array 51 shown in FIG. 7 can be molded by pouring into the space (cavity) formed by the female mold 42 and the flat mold 43, cooling and then opening the mold. it can.

As described above, according to the embodiment of the present invention, it is possible to obtain the desired aspherical lens array 51 in which the focal points of the respective lenses are located on the same plane. Also,
Since the resist 22 is exposed by using X-ray lithography to manufacture the aspherical lens array master block 31B, it is possible to manufacture a mold for molding the aspherical lens array 51 having a curved surface accuracy of submicron or less. .

In the above embodiment, the aspherical lens array 51 has a focal point on the same plane, but the aspherical lens array has a focal point on the same straight line, one row and a plurality of columns, or a plurality of rows and one column. Needless to say, it may be an aspherical lens array.

Further, although the example in which the molding material for molding the aspherical lens array 51 is low melting point glass is shown, the mold 41 is made of platinum (Pt) even if the molding material is ordinary glass or resin. Therefore, it is possible to mold the aspherical lens array 51 having a desired shape and a high surface accuracy without causing the shape deterioration of the mold 41 due to the molding temperature, and when the molding material is low melting point glass. , A metal for manufacturing the die 41 is nickel (Ni), a metal having a linear expansion coefficient similar to that of nickel (16.9 × 10 ⁻¹⁶ ), such as iron (Fe) -nickel alloy, nickel. −
Cobalt (Co) alloy, etc.] enables the die to be manufactured at low cost. As described above, when the mold 41 is made of nickel (Ni) or a metal having a linear expansion coefficient similar to that of nickel, the linear melting coefficient of the low melting point glass and the mold 41 are substantially the same. Since the mold 41 and the aspherical lens array 51 behave the same from the time of molding to the time of completion, the aspherical lens array 51 in which the shape of the mold 41 is accurately duplicated can be obtained.

[0031]

As described above, according to the aspherical lens array of the present invention, it is possible to obtain the desired aspherical lens array in which the focal points of the respective lenses are located on the same straight line or the same plane. .

Next, according to the mold manufacturing method of the present invention, since the resist is exposed by using X-ray lithography to manufacture the master mold of the aspherical lens array, the surface accuracy of the curved surface is less than submicron. It is possible to manufacture a mold for molding the aspheric lens array. Since the metal forming the die is a metal having a linear expansion coefficient similar to that of nickel, the die can be manufactured at low cost.

Next, according to the method for manufacturing an aspherical lens array of the present invention, it is possible to mold an aspherical lens array in which the surface accuracy of the curved surface is submicron or less. Then, since the aspherical lens array is formed by using a glass (low melting point glass) having a melting point of 350 ° C. to 450 ° C., or a glass having a linear expansion coefficient similar to that of nickel is used. Since the aspherical lens array is molded, the production cost of the aspherical lens array can be reduced. In addition, it is not necessary to manufacture the mold with platinum in consideration of the mold shape deterioration (deformation) due to the high molding temperature and the mold high temperature measures, and a metal having a linear expansion coefficient similar to that of nickel. The mold can be manufactured with. Therefore, the mold can be manufactured at low cost.

[Brief description of drawings]

FIG. 1 is a plan view showing a mask used in a mold manufacturing method of the present invention.

FIG. 2 is a perspective view showing a resist and the like for manufacturing a mother die for manufacturing a die.

3A and 3B are explanatory views for forming a master mold of a spherical lens array and a master mold of an aspherical lens array on a resist.

FIG. 4 is an explanatory diagram for forming a mother die of a spherical lens and a mother die of an aspherical lens.

FIG. 5 is an explanatory diagram for manufacturing a mold for molding an aspherical lens array.

FIG. 6 is an explanatory diagram of molding an aspherical lens array using a mold.

FIG. 7 is a perspective view showing an aspherical lens array.

[Explanation of symbols]

11 masks 12 Membrane material 13 X-ray absorption film 13a half circle 13b Transparent part 13p contour line 13q 1st straight line part 13r Second straight section 13s third straight line part 21 Conductor substrate 22 Resist 22a spherical lens matrix 22b Aspherical lens matrix 31A spherical lens array matrix 31B Aspherical lens array matrix 41 mold 42 female 43 flat type 51 Aspherical lens array A, B curve

Claims (6)

[Claims] 1. An aspherical lens array, wherein the curved surface of each lens is an aspherical surface, and the focal points of the respective lenses are located on the same straight line or the same plane. 2. A plurality of semicircles are arranged in a straight line, and a mask having transmissive portions between the semicircles and the left and right of the semicircles is placed on a resist, and the mask is formed into an aspheric lens array. The apex of the semicircle reaches the apex of each aspherical lens from the upper end of each aspherical lens toward the lower end of each aspherical lens so that the exposure time forms the curved surface of the aspherical lens to be formed. Until the apex of the semicircle reaches the apex of the aspherical lens from the lower end of the aspherical lens to the upper end of the aspherical lens, from the left end of the aspherical lens to the aspherical lens. Until the apex of the semicircle reaches the apex of the aspherical lens in the right end direction of the aspherical lens from the right end of the aspherical lens to the left end of the aspherical lens. Until reaching the top of The resist is exposed by X-ray lithography, and at least a female mold of the mold for manufacturing the aspherical lens array is manufactured by plating based on the master mold developed by developing the resist. Mold manufacturing method. 3. The mold manufacturing method according to claim 2, wherein the metal for manufacturing the mold is a metal having a linear expansion coefficient similar to that of nickel. Method. 4. A method for manufacturing an aspherical lens array, which comprises using the mold according to claim 2 or 3 and molding the aspherical lens array using a molding material of resin or glass. 5. The manufacturing of an aspherical lens array using the mold according to claim 3, wherein the aspherical lens array is molded using glass having a melting point of 350 ° C. to 450 ° C. Method. 6. The mold according to claim 3, wherein the aspherical lens array is molded using glass having a linear expansion coefficient similar to that of nickel. Manufacturing method of aspherical lens array.