JP2012087050A - Method for manufacturing lens array, and molding die assembly - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for manufacturing a lens array of stable quality with high productivity at a low cost by surely preventing the generation of an air pocket upon molding.SOLUTION: In a molding method, a flat convex-shaped molding material 40 is inserted into a space between a lower die 12 and an upper die 13 each inserted into a sleeve 11 of a molding die assembly 10 to face each other, and a plurality of small lens molding recessed faces 13b formed at the molding face 13a of the upper die 13 are transferred. The method includes positioning and molding the lens array in such a manner that the surface center part 43 of the convex-shaped surface 42 in the flat convex-shaped molding material 40 is made coincident with the recessed face tip 13c at the center of the arrangement of the plurality of small lens molding recessed faces 13b in the upper die 13, so that the air in the small lens molding recessed faces 13b is promptly exhausted to the outer circumferential direction with the deformation of the flat convex-shaped molding material 40, and the generation of an air pocket at the small lens molding recessed faces 13b is prevented.

Description

  The present invention relates to a lens array manufacturing technique and a mold assembly, for example, a technique for manufacturing a lens array, which is an assembly of a plurality of small lenses, by mold molding.

A lens array that is an assembly of a plurality of lenses is used as a lens for illumination, optical fiber communication, sensor condensing, and the like.
As a method of manufacturing this lens array, a method of manufacturing a lens array by pressing a single parallel flat plate-shaped molding material made of a material such as glass or plastic with a mold while softening is conventionally known. .

  In such a general method for manufacturing a lens array by molding, there is a technical problem that the quality of the lens array is difficult to stabilize and the yield is not good because air pockets are easily generated in the small lens portion.

For this reason, Patent Document 1 discloses a method of manufacturing a lens array by housing a molding die in a vacuum chamber, heat-softening a glass molding material in a vacuum, and pressing it with a mold.
Further, in Patent Document 2, a center nest on which a glass preform is placed is provided at the center of an array region of a plurality of microlens cavities in a mold, and a single glass preform is disposed on the center nest, and heating is performed. After pressing the mold in a state and deforming the molten glass preform so that it spreads from the central nest part to the surrounding microlens cavity, and molding the lens array, the small lens so that the central nest part is removed from the lens array The manufacturing method which cuts out a part and obtains a microlens array is proposed.

  However, in the technique of the above-mentioned Patent Document 1, in order to accommodate the entire mold in the chamber and heat it in vacuum, a large vacuum facility such as a chamber and a vacuum pump is required, which increases the cost of the entire molding apparatus. In turn, there is a technical problem that the cost of the molded product increases.

  In addition, there is a technical problem that a redundant required time such as a vacuum evacuation process before molding and a return process to atmospheric pressure after molding occurs, resulting in a decrease in productivity due to an increase in cycle time in the molding process.

  On the other hand, in the case of Patent Document 2, since the central nest portion where the glass preform is disposed cannot be used as an optical surface, the design of the moldable microlens array and the shape specification that can be molded are limited, and the When cutting the central nest located at the center of the lens array, the yield of the glass preform is reduced, and the cycle time is increased and the manufacturing cost is increased by the amount of the cutting process, resulting in a decrease in productivity. There is a technical problem.

JP-A-6-144842 JP 2001-48554 A

  The object of the present invention is to eliminate the need for manufacturing equipment larger than necessary, without causing an increase in cycle time and an increase in manufacturing cost in the molding process, without restricting the shape of the lens array, and at the time of molding. It is an object of the present invention to provide a technique capable of reliably preventing the occurrence of air accumulation and manufacturing a lens array of stable quality with high productivity and low cost.

The present invention includes a step of positioning so that the top of the convex molding material is aligned with the center of the array of the plurality of optical functional concave surfaces arranged on at least one molding surface of the upper mold and the lower mold,
Clamping the molding material between the molding surfaces of the upper mold and the lower mold, and deforming the molding material so that the molding material spreads in the peripheral direction from the center of the arrangement; and
Including
A plurality of the optical function concave surfaces are arranged on the molding surface such that a boundary portion between the adjacent optical function concave surfaces coincides with the arrangement center,
A lens array in which the shape of the molding material is set so as to satisfy Rp ≦ 2Ra, where Ra is the minimum curvature radius of each concave surface of the optical function and Rp is the curvature radius of the top of the molding material. A manufacturing method is provided.

  According to the present invention, an excessively large manufacturing facility is not required, the cycle time in the molding process is increased and the manufacturing cost is not increased, the shape of the lens array is not restricted, and molding is performed. Thus, it is possible to provide a technique capable of reliably preventing the occurrence of air accumulation and manufacturing a lens array of stable quality with high productivity and low cost.

1 is a schematic side view showing an example of a configuration of a molding apparatus in which a lens array manufacturing method according to an embodiment of the present invention is implemented. It is sectional drawing which shows an example of the assembly state in the normal temperature of the shaping | molding die assembly which implements the manufacturing method of the lens array which is one embodiment of this invention. It is sectional drawing which expands and illustrates a part of it. It is sectional drawing which shows the shaping | molding state under the heating. It is a side view which shows an example of the lens array shape | molded with the shaping | molding die assembly which is one embodiment of this invention. It is a top view which shows an example of the molding surface of the upper mold | type in the shaping | molding die assembly which is one embodiment of this invention. It is sectional drawing which shows the plano-convex shaped raw material used for shaping | molding which is one embodiment of this invention. It is sectional drawing which shows the assembly state of the shaping | molding die assembly in the normal temperature in the manufacturing method of the lens array of other embodiment of this invention. It is sectional drawing which shows the shaping | molding state under the heating. It is sectional drawing which shows an example of the lens array obtained by the manufacturing method. It is a top view which shows the arrangement | sequence state of the several small lens molding surface arrange | positioned at the molding surface of the upper mold | type which comprises the shaping | molding die assembly used for the manufacturing method of the lens array. It is explanatory drawing for demonstrating the deformation | transformation process of the shaping | molding raw material in the manufacturing method of the lens array. It is sectional drawing which shows the assembly state of the shaping | molding die assembly in normal temperature in the modification of the manufacturing method of the lens array of other embodiment of this invention. It is a perspective view which shows the shape of the molding surface of the upper mold | type in the modification. It is a top view which shows the shape of the molding surface of the upper mold | type in the modification. It is a perspective view which shows the rectangular lens array obtained in the modification. It is the perspective view which illustrated the external appearance of the convex lens cross-section shaping | molding raw material used for the other modification of the manufacturing method of the lens array of other embodiment of this invention. It is a perspective view which shows the external appearance of the lens array obtained from the convex lens cross-section molding raw material. It is a top view which shows the arrangement | sequence state of the some small lens molding surface which consists of a concave semi-cylindrical surface of the upper mold | type in the modification. It is a perspective view which shows the arrangement | sequence state of the some small lens molding surface which consists of the concave semi-cylindrical surface of the upper mold | type in the modification. It is a perspective view which shows the lens array shape | molded by the small lens molding surface. It is sectional drawing which shows the lens array by which the convex small lens part is arrange | positioned on both surfaces of the board | substrate part. It is a side view which shows an example of the shaping | molding raw material used for shaping | molding of the lens array.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a schematic side view showing an example of a configuration of a molding apparatus in which a lens array manufacturing method according to an embodiment of the present invention is implemented.

  FIG. 2A is a cross-sectional view showing an example of an assembly state at room temperature of a mold assembly for carrying out a method for manufacturing a lens array according to an embodiment of the present invention, and FIG. 2B is an enlarged view of a part thereof. FIG. 2C is a cross-sectional view illustrating a molded state under heating, and FIG. 2D is a side view illustrating an example of a lens array molded by the mold assembly of the present embodiment.

FIG. 3 is a plan view showing an example of the molding surface of the upper mold in the molding die assembly of the present embodiment, and FIG. 4 is a cross-sectional view showing a plano-convex molding material used for molding of the present embodiment. is there.
First, with reference to FIG. 2D, a lens array 40A manufactured by the lens array manufacturing method of the present embodiment will be described.

The lens array 40A manufactured in the present embodiment includes a substrate portion 41a and an array of a plurality of small lens portions 42a provided on one surface of the substrate portion 41a.
The substrate portion 41a has a circular parallel plate shape. Each of the small lens portions 42a has a convex shape, and is mainly a spherical surface having a certain radius of curvature.

In this case, the number of small lens portions 42a is, for example, 9 × 3 × 3, and is arranged as a square array at equal intervals on one surface of the substrate portion 41a.
As a material of the lens array 40A, that is, a plano-convex molding material 40 (molding material) described later used for molding the lens array 40A, optical glass transparent in the visible range is used. In this embodiment, an example in which commercially available L-BSL7 (glass transition point 498 ° C., yield point 549 ° C.) is used as the optical glass will be described.

As illustrated in FIG. 1, the molding apparatus 100 according to the present embodiment includes a molding stage 110, a lower plate 120, an upper plate 130, and a pressure device 140.
A lower plate 120 is disposed on the molding stage 110, and an upper plate 130 that is driven in the vertical direction by the pressurizing device 140 is provided at a position facing the lower plate 120 in the vertical direction.

  The molding apparatus 100 according to the present embodiment can be of any configuration that can operate in the atmosphere or in a replacement atmosphere such as nitrogen gas. That is, there is no need to attach a vacuum vessel, a vacuum pump, or the like to the molding apparatus 100.

  In the manufacturing process of the lens array using the molding apparatus 100, the molding die assembly 10 in which a molding material such as the plano-convex molding material 40 is incorporated is placed on the lower plate 120 in the molding apparatus 100. .

  A plurality of heaters 121 and 131 are mounted inside each of the lower plate 120 and the upper plate 130, and the mold assembly 10 sandwiched between the lower plate 120 and the upper plate 130 is provided. It is possible to heat to a desired molding temperature.

Note that an infrared lamp may be arranged around the side surface of the mold assembly 10 in place of the heater 121 and the heater 131 and heated.
As described above, the lower plate 120 is fixed to the molding stage 110, and the pressing device 140 is connected to the upper plate 130.

  By lowering the upper plate 130 by the pressurizing device 140, the mold assembly 10 is sandwiched between the lower plate 120 and the upper plate 130, and further pressed when being pressed by the upper plate 130. .

As illustrated in FIG. 2A, the mold assembly 10 of the present embodiment includes a cylindrical sleeve 11, a lower mold 12, and an upper mold 13 having a columnar outer shape.
The upper mold 13 and the lower mold 12 can be fitted into the sleeve 11 by being inserted from both ends of the sleeve 11 so that the respective molding surfaces 13a and 12a face each other.

When the sleeve 11, the lower mold 12, and the upper mold 13 constituting the mold assembly 10 are fitted, the central axes of the upper mold 13, the lower mold 12, and the sleeve 11 are configured to coincide with each other.
In the following, the central axis in the opposing direction of the upper mold 13 and the lower mold 12 is referred to as a central axis CZ, and two axes orthogonal to each other in a plane orthogonal to the central axis CZ are referred to as a central axis CX and a central axis CY. .

In the center of the molding surface 13a of the upper mold 13, a plurality of small lens molding concave surfaces 13b (optical functional concave surfaces) corresponding to the plurality of small lens portions 42a of the lens array 40A are arranged.
Each small lens molding concave surface 13b is formed to match the corresponding small lens portion 42a, and has a concave shape and a constant radius of curvature R0. In this case, the number of the small lens molding concave surfaces 13b is nine (L11 to L33), and the small lens molding concave surfaces 13b are arranged in an array state in which the centers of the small lens molding concave surfaces 13b coincide with the lattice points of the square lattice.

Here, the small lens molding concave surface 13b in the upper mold 13 of the mold assembly 10 of the present embodiment will be described in more detail.
The molding surface 13a of the cylindrical upper mold 13 as described above has a circular outer shape, and the center of the outer circle (center axis CZ) is set as the center of the molding surface 13a. The central portion of the molding surface 12a of the lower mold 12 is set in the same manner.

In the arrangement (L11 to L33) of the plurality of small lens molding concave surfaces 13b in the upper mold 13, attention is paid to one small lens molding concave surface 13b (L22) located at the center.
In the case of the upper mold 13 of the present embodiment, the apex of the small lens molding concave surface 13b (L22) (concave surface apex 13c (array central portion)) coincides with the central portion (central axis CZ) of the molding surface 13a. A plurality of small lens molding concave surfaces 13b are arranged in alignment.

In this case, the molding surface 12a of the lower mold 12 is formed on a flat surface orthogonal to the central axis CZ.
In the case of the present embodiment, for example, cemented carbide, silicon carbide, stainless steel, or the like can be used as the material constituting the upper mold 13, the lower mold 12, and the sleeve 11 of the mold assembly 10.

The shape of the small lens molding concave surface 13b is manufactured by selecting or combining appropriate processes among cutting, grinding, polishing and the like.
Next, the molding material used in the present embodiment will be described.

  In the present embodiment, a plano-convex molding material 40 having a lens shape with a plano-convex cross section is used. That is, the plano-convex molding material 40 has an appearance in which a bottom surface 41 is formed at one end of a cylinder and a convex surface 42 made of, for example, a spherical surface is formed at the other end. The plano-convex molding material 40 is composed of a single member.

  Further, the volume of the plano-convex molding material 40 is matched with the volume of the lens array 40A described above manufactured using the plano-convex molding material 40. Thereby, the lens array 40A having a target shape can be obtained without requiring additional processing such as cutting off after molding.

The convex surface 42 of the plano-convex molding material 40 has a certain radius of curvature, and the surface center portion 43 (top portion) is the highest vertex from the bottom surface 41.
Here, in the plano-convex molding material 40 of the present embodiment, the curvature radius Rp of the convex surface 42 is set as follows.

  Focusing on the minimum curvature radius Ra of the small lens molding concave surface 13b formed on the upper mold 13, the small lens molding concave surface 13b has a constant curvature radius R0. Therefore, the minimum curvature radius Ra is an individual small lens molding concave surface. This coincides with the curvature radius R0 of 13b.

In the present embodiment, the curvature radius Rp of the convex surface 42 of the plano-convex molding material 40 satisfies the relationship of the following formula (1) with respect to the minimum curvature radius Ra of the small lens molding concave surface 13b. Set as follows.
Rp ≦ Ra (1)

The material of the plano-convex molding material 40 to be the lens array 40A is made of optical glass and uses the above-described L-BSL7.
This plano-convex molding material 40 is manufactured in advance in the above-described shape by grinding, polishing, or molten glass pressing.
The operation of the lens array manufacturing method by glass molding in the present embodiment will be described below.

The manufacturing process of the lens array of the present embodiment includes an assembly process of the mold assembly 10, a heating process, a molding process, and a cooling process.
First, the assembly process of the mold assembly 10 will be described.

The plano-convex molding material 40 is placed on the molding surface 12a of the lower mold 12 with the bottom surface 41 facing downward.
At this time, the position of the plano-convex molding material 40 is positioned so that the center of the plano-convex molding material 40 coincides with the center of the molding surface 12a of the lower mold 12.

In this state, the sleeve 11 and the lower mold 12 are fitted together, and the upper mold 13 is fitted so that the molding surface 13 a faces the plano-convex molding material 40 on the lower mold 12.
When the upper mold 13 and the lower mold 12 are inserted into the sleeve 11, the central portion of the upper mold 13 and the central portion of the lower mold 12 are aligned on the central axis (center axis CZ) of the hole of the sleeve 11. become.

  That is, the surface center portion 43 (vertex) at the center of the convex surface 42 of the plano-convex molding material 40 is at the center of the molding surface 13a of the upper mold 13, that is, the array center of the plurality of small lens molding concave surfaces 13b. The small lens molding concave surface 13b (L22) is positioned so as to be aligned with the concave vertex 13c of the central axis CZ.

In this way, the plano-convex molding material 40 is sandwiched between the upper mold 13 and the lower mold 12 that are inserted so as to face the sleeve 11, thereby obtaining the mold assembly 10 as shown in FIG. 2A.
As shown in FIG. 2B, in a state where the plano-convex molding material 40 is sandwiched between the lower mold 12 and the upper mold 13, the small mold positioned at the center of the array of the plurality of small lens molding concave surfaces 13b in the upper mold 13 is used. The concave surface vertex 13c of the lens molding concave surface 13b (L22) and the surface center portion 43 of the convex surface 42 of the plano-convex molding material 40 are in contact with each other.

However, the small lens molding concave surface 13b (L22) and the plano-convex molding material 40 are not in contact with portions other than the concave vertex 13c.
Next, the heating process of the mold assembly 10 configured as described above will be described.

The molding die assembly 10 in which the plano-convex molding material 40 is assembled is placed between the lower plate 120 and the upper plate 130 in the molding apparatus 100.
Through the lower plate 120 and the upper plate 130, the mold assembly 10 and the plano-convex molding material 40 inside only a predetermined time so as to reach a molding temperature corresponding to the material of the plano-convex molding material 40. Heat.

This molding temperature is set to a temperature higher than the yield point temperature of the glass used for the plano-convex molding material 40. As a result, the plano-convex molding material 40 is softened at the molding temperature.
Next, the molding process will be described.

The mold assembly 10 is pressurized by the lower plate 120 and the upper plate 130 of the molding apparatus 100 while being held at the molding temperature described above.
In the molding die assembly 10, the plano-convex molding material 40 sandwiched between the lower die 12 and the upper die 13 is deformed, and the space between the molding surface 12a of the lower die 12 and the molding surface 13a of the upper die 13 is deformed. Will be filled.

  As the deformation progresses, the shape of the molding surface 12a and the molding surface 13a (small lens molding concave surface 13b) is transferred to the plano-convex molding material 40, whereby the substrate portion 41a and the plurality of small lens portions 42a of the lens array 40A are transferred. Is formed.

  Here, in the case of the present embodiment, in the initial stage of deformation, the softened plano-convex molding material 40 is surrounded from the center (concave surface vertex 13c) of the small lens molding concave surface 13b (L22) at the center of the array. It is pushed toward the adjacent line 13d.

  For this reason, the air existing inside the small lens molding concave surface 13b (L22) is sequentially pushed out by the plano-convex molding material 40 which deforms so as to spread outward from the concave vertex 13c, and the inside of the small lens molding concave surface 13b. Does not stay.

  That is, since the cross section opened in the outer peripheral direction is always formed as a substantially wedge-shaped space around the contact portion of the concave surface vertex 13c of the small lens molding concave surface 13b and the surface center portion 43 of the plano-convex molding material 40, the concave surface Along with the deformation of the convex surface 42 of the plano-convex molding material 40 that spreads in the outer circumferential direction around the vertex 13c, the air in the small lens molding concave surface 13b is reliably driven out and eliminated.

  In each peripheral small lens molding concave surface 13b adjacent to the small lens molding concave surface 13b (L22) located in the center, the soft plano-convex molding material 40 is directed from the center of the molding surface 13a toward the outer periphery. It enters along the surface shape of the small lens molding concave surface 13b.

  Along with this, the air existing inside each small lens molding concave surface 13b in the peripheral part is also pushed out in the outer peripheral direction of the molding surface 13a along the deformation flow of the plano-convex molding material 40, Absent.

Even if air remains in the small lens molding concave surface 13b, it remains at a level at which a slight air pocket is formed at the ridge line portion of the adjacent line 13d of each small lens molding concave surface 13b.
In this manner, the surface of each small lens portion 42a of the lens array 40A obtained from the plano-convex molding material 40, that is, the optical surface, can be molded with almost no air remaining.

  If the pressing of the upper plate 130 is stopped when the desired shape of the lens array 40A is obtained from the plano-convex molding material 40, the molding of the lens array 40A is completed, and the lens array 40A having the appearance illustrated in FIG. Is obtained.

  In order to obtain the desired shape of the lens array 40A, the amount of movement of the upper plate 130 is controlled when the mold assembly 10 is pressed between the upper plate 130 and the lower plate 120 as described above. Alternatively, the pressing force and the pressurizing time may be set and controlled.

Next, the cooling process after molding as described above will be described.
In the cooling process of the lens array 40A, the heated optical glass is shifted from the softened state to the solidified state to stabilize the shape of the lens array 40A.

The mold assembly 10 is cooled by a cooling device (not shown).
During cooling, a pressurized state may be necessary to ensure transfer accuracy and reduce distortion of the molded lens array 40A.

The pressure applied during cooling is set within a range that does not cause cracks in the molded product such as the lens array 40A.
Cooling is completed when the mold assembly 10 and the molded lens array 40A are cooled to near room temperature.

After this cooling is completed, the lens array 40A can be obtained by removing the upper mold 13 from the mold assembly 10 and taking out the molded product.
The shape of the lens array 40A formed in the present embodiment is an example, and the shape of the substrate portion 41a, the shape and number of the small lens portions 42a in the lens array 40A illustrated in FIG. About the kind of glass constituting the convex molding material 40 (lens array 40A), the arrangement of the small lens molding concave surface 13b in the upper mold 13, the shape of the plano-convex molding material 40, the order of the manufacturing process, etc. It is not limited to.

For example, the shape of the substrate portion 41a in the lens array 40A may be a rectangle, a polygon, or the like other than the circle exemplified in the present embodiment, depending on the application and the state of attachment to the frame.
Further, the shape and number of the small lens portions 42a in the lens array 40A can be changed according to the required optical performance and specifications.

The substrate portion 41a and the small lens portion 42a of the lens array 40A are made of the same glass, and the type of glass is not limited.
In the mold assembly 10, the small lens molding concave surface 13 b may be formed not on the upper mold 13 but on the molding surface 12 a of the lower mold 12.

In the present embodiment, the upper mold 13 and the lower mold 12 are each configured by a single component, but may be configured by combining a plurality of separate components.
For example, in the case of the upper mold 13, a structure in which a nested part having a small lens molding concave surface 13b is fitted to a basic part having a molding surface 13a may be used.

The molding material is not limited to the plano-convex molding material 40, and may be other than the plano-convex lens shape as long as it has a convex curved surface.
For example, a biconvex lens shape, a ball shape, an egg shape, a rugby ball shape, a gob shape, or the like can be used.

  Alternatively, although not particularly illustrated, a convex conical surface may be provided on the end surface of the cylinder, and the apex of the conical surface may be the surface center portion 43 so that the curvature radius Rp of the apex is arbitrarily set.

  In the manufacturing process of the lens array exemplified in the present embodiment, an example in which an assembly process, a heating process, a molding process, and a cooling process are combined has been described. However, when combined with an automatic assembly apparatus, the order of the assembly process and the heating process is switched. It is also possible to manufacture in the order in which the assembly process is inserted after the heating process.

As a post-process, in order to secure the outer dimensions of the lens array 40A, if necessary, a step of centering the substrate portion 41a may be added to scrape off the excess outer diameter portion.
Alternatively, the inner diameter of the sleeve 11 and the outer diameters of the lower mold 12 and the upper mold 13 are adjusted in order to eliminate the centering operation, and the inner wall surface of the sleeve 11 is used as a deformation restricting portion that defines the outer shape of the substrate portion 41a. It is also possible to do.

Further, the deformation restricting portion may be constituted by another member other than the sleeve 11.
Deformation in the outer diameter direction of the softened molding material is restricted by the deformation restricting portion. When molding is completed, the space surrounded by the inner wall surface of the sleeve 11, the upper mold 13 and the lower mold 12 is filled with the deformed molding material, and the lens array 40A having a desired outer dimension is obtained.

When a function such as antireflection is added, the surface of the lens array 40A is coated in a later process.
According to the manufacturing method of the lens array of the present embodiment, the small lens located at the center of the array of the plurality of small lens molding concave surfaces 13b on the molding surface 13a of the upper mold 13 is the surface center portion 43 of the plano-convex molding material 40. Due to the deformation of the plano-convex molding material 40, it is made to coincide with the concave vertex 13c of the molding concave surface 13b and the curvature radius Rp of the surface center portion 43 is smaller than the minimum curvature radius Ra of the small lens molding concave surface 13b. During molding, air inside the small lens molding concave surface 13b can be surely excluded from the center portion 43 of the surface of the plano-convex molding material 40 toward the outer periphery, and even if a single plano-convex molding material 40 is used. It is possible to manufacture a lens array 40A having a good quality free from air accumulation.

  Furthermore, it is not necessary to house the entire mold assembly 10 in a large vacuum chamber or the like for the purpose of avoiding molding defects caused by air trapping on the small lens molding concave surface 13b during molding. It is possible to suppress the cost increase of the molding equipment due to the addition and the like, and hence the cost increase of the lens array 40A, and the time required for the entire molding process (excessive time such as evacuation and return to atmospheric pressure) does not occur in the molding process. Productivity can be improved by shortening the cycle time.

  Further, it is necessary to provide a special shape portion different from the small lens molding concave surface 13b for arranging the plano-convex molding material 40 on the molding surface 13a of the upper mold 13 on which the plurality of small lens molding concave surfaces 13b are arranged. Therefore, the entire molding surface 13a can be effectively used for molding the lens array 40A, and the lens array 40A having a desired shape specification or design specification in which the small lens molding concave surface 13b having an arbitrary shape is freely arranged can be molded.

  Furthermore, an extra process such as excision after molding a special shape portion different from the small lens molding concave surface 13b for arranging the plano-convex molding material 40 is eliminated, eliminating the time required for the excision process, The yield can be improved by reducing the amount of molding material thrown away by excision, and the productivity is further improved.

In other words, according to the present embodiment, the shape of the lens array is restricted without requiring an unnecessarily large manufacturing facility, without causing an increase in cycle time or an increase in manufacturing cost in the molding process. Therefore, it is possible to reliably prevent the occurrence of air accumulation during molding, and to manufacture a lens array with stable quality with high productivity and low cost.
(Second Embodiment)
In the first embodiment described above, the surface center portion 43 of the plano-convex molding material 40 is brought into contact with the concave surface vertex 13c of the small lens molding concave surface 13b at the center of the arrangement of the plurality of small lens molding concave surfaces 13b on the molding surface 13a. In the second embodiment, the center portion 43 of the surface of the plano-convex molding material 40 is made to coincide with the edge-shaped boundary portions of a plurality of adjacent small lens molding concave surfaces. An example of assembling the mold assembly 10 will be described.

  Since the basic configurations of the molding apparatus 100 and the mold assembly are the same as those in the first embodiment, the same components are denoted by the same reference numerals, and duplicate descriptions are omitted, and the differences are described. To do.

  FIG. 5A is a cross-sectional view showing an assembled state of the mold assembly at room temperature in the manufacturing method of the lens array of the second embodiment, and FIG. 5B is a cross-sectional view showing a molded state under heating. FIG. 5C is a cross-sectional view showing an example of a lens array obtained after molding.

FIG. 6 is a plan view showing an arrangement state of a plurality of small lens molding surfaces arranged on the molding surface of the upper mold constituting the molding die assembly in the present embodiment.
FIG. 7 is an explanatory diagram for explaining a deformation process of the molding material according to the second embodiment.

First, the lens array 40B molded in the second embodiment will be described.
As illustrated in FIG. 5C, in the lens array 40B of the present embodiment, the number of small lens portions 42a is 2 × 2, and is arranged as a square array at equal intervals Xp on one surface of the substrate portion 41a. Is done.

  As the material of the lens array 40B, optical glass transparent in the visible range is used. In this embodiment, an example in which a commercially available L-BSL7 (glass transition point 498 ° C., yield point 549 ° C.) is used as the optical glass will be described.

  In order to mold the lens array 40B having such a shape, in the mold assembly 10A of the present embodiment, an upper mold having the shape of the molding surface illustrated in FIG. 6 is used instead of the upper mold 13 described above. 14 is used.

On the molding surface 14a of the upper mold 14, small lens molding concave surfaces 14b (optical functional concave surfaces) corresponding to the individual small lens portions 42a of the lens array 40B are arranged.
Each small lens molding concave surface 14b is formed such that the shape of each small lens portion 42a of the corresponding lens array 40B is transferred.

  The small lens forming concave surface 14b has a concave shape and a constant radius of curvature, and the total number formed on the molding surface 14a is four, arranged as a square array (L11 to L22), and adjacent small lenses. An edge-shaped adjacent boundary 14c exists between the molding concave surfaces 14b.

The arrangement state of the plurality of small lens molding concave surfaces 14b in the upper mold 14 of the present embodiment will be described.
The molding surface 14a of the upper mold 14 has a circular outer shape, and the center of the circle is set at the center of the molding surface 14a.

  In this case, in the arrangement (L11 to L22) of the plurality of small lens molding concave surfaces 14b on the molding surface 14a, the adjacent boundaries 14c in the central axis CY direction and the central axis CX direction intersect at the center of the molding surface 14a, It is an adjacent intersection 14d (arrangement center) (P1).

  That is, in the case of this mold assembly 10A, the plurality of small lens molding concave surfaces 14b are arranged so that the adjacent intersection 14d (P1) coincides with the center portion (center axis CZ) of the molding surface 14a of the upper mold 14. Arranged in line.

The molding surface 12a of the lower mold 12 is formed in a flat shape as in the first embodiment.
Next, the plano-convex molding material 40 used in the second embodiment will be described.

The plano-convex molding material 40 used in the second embodiment is substantially the same as that of the first embodiment described above, but the setting condition of the curvature radius Rp of the convex surface 42 on which the surface center portion 43 is formed is different. .
That is, when attention is paid to the minimum curvature radius Ra of the plurality of small lens molding concave surfaces 14b formed on the upper mold 14, the individual small lens molding concave surfaces 14b have a constant curvature radius R0. Ra coincides with each radius of curvature R0.

In the case of the second embodiment, the radius of curvature Rp of the convex surface 42 of the plano-convex molding material 40 is set to be a small lens molding concave surface in order to prevent air accumulation of the small lens molding concave surface 14b according to the principle described later. It sets so that the relationship of the following formula | equation (2) may be satisfied with respect to the minimum curvature radius Ra of 14b.
Rp ≦ 2Ra (2)

Next, in the second embodiment, an example of the operation of the lens array manufacturing method by glass molding using the mold assembly 10A will be described.
First, the assembly process of the mold assembly 10A will be described.

The flat bottom molding material 40 is placed on the molding surface 12a of the lower mold 12 with the flat bottom 41 side facing down.
At this time, the position of the plano-convex molding material 40 is such that the center of the plano-convex molding material 40 (in this case, the surface center portion 43) with respect to the center of the molding surface 12a of the lower mold 12 (center axis CZ). Position to match.

When the upper mold 14 and the lower mold 12 are inserted into the sleeve 11, the central portion of the upper mold 14 and the central portion of the lower mold 12 are aligned on the central axis of the sleeve 11.
The surface center portion 43 located at the apex of the center portion of the convex surface 42 of the plano-convex molding material 40 is the adjacent intersection 14d ( P1) and align on the central axis CZ.

In this manner, the mold assembly 10A is obtained by sandwiching the plano-convex molding material 40 between the upper mold 14 and the lower mold 12 through the sleeve 11.
In the state where the plano-convex molding material 40 is sandwiched between the upper mold 14 and the lower mold 12 inside the mold assembly 10A, the adjacent intersection 14d (P1) located at the center of the molding surface 14a and the plano-convex shape. The surface center portion 43 of the convex surface 42 of the molding material 40 is substantially in point contact.

However, the molding surface 14a of the upper mold 14 and the plano-convex molding material 40 are not in contact at portions other than the adjacent intersection 14d (P1).
Next, a molding process using the mold assembly 10A assembled as described above will be described.

  When the mold assembly 10A is heated to a predetermined molding temperature and pressed between the lower plate 120 and the upper plate 130 in the molding apparatus 100, the plano-convex molding sandwiched between the lower mold 12 and the upper mold 14 is performed. The material 40 fills the space between the lower mold 12 and the upper mold 14 while deforming.

In the initial stage of this deformation, the soft plano-convex molding material 40 is spread from the adjacent intersection 14d (P1) toward the outer periphery.
When the deformation progresses and the outer peripheral portion at the lower end of the plano-convex molding material 40 reaches the inner peripheral surface of the sleeve 11, the substrate portion 41a and the plurality of small lens portions 42a of the lens array 40B are formed.

  Here, when the molding surface 14 a of the upper mold 14 is displaced following the deformation of the plano-convex molding material 40, the individual small lens molding concave surface 14 b and the convex surface 42 of the plano-convex molding material 40. If control is performed so that a closed space is not created between them, the occurrence of air pockets can be prevented.

Referring to FIG. 7, the above-described conditions for not creating the closed space are as follows.
This condition includes a tangent line T1 formed by the spherical surface of the small lens molding concave surface 14b at the position of the adjacent intersection (adjacent boundary 14c) adjacent to the adjacent intersection 14d of interest, and the convex surface 42 of the plano-convex molding material 40. It is necessary not to intersect the tangent line T2 formed by the spherical surface.

  That is, the difference Δθ = θ2−θ1 between the angle θ2 formed by the tangent T2 of the convex surface 42 and the molding surface 14a and the angle θ1 formed by the tangent T1 of the small lens molding concave surface 14b and the molding surface 14a is Δθ ≧ 0. The tangent line T1 and the tangent line T2 do not intersect.

  Therefore, from the geometrical relationship, if the relationship of Rp ≦ 2Ra is satisfied with respect to the curvature radius Rp of the convex surface 42 and the minimum curvature radius Ra of the small lens molding concave surface 14b, each of the tangent line T1 and the tangent line T2 described above is satisfied. Conditions that do not intersect can be realized.

  As shown in the above formula (2), the curvature radius Rp of the convex surface 42 in the plano-convex molding material 40 of the second embodiment is equal to the minimum curvature radius Ra of the small lens molding concave surface 14b. The relationship of ≦ 2Ra is satisfied.

  As a result, in the case of the second embodiment, the deformation range of the plano-convex molding material 40 increases the contact range from the central portion toward the peripheral portion so as to sequentially follow the surface shape of the small lens molding concave surface 14b. Proceed as follows.

  Therefore, in each small lens molding concave surface 14b, the air existing inside is surely excluded so as to be pushed out from the center of the molding surface 14a in the outer peripheral direction along the flow of the deformed plano-convex molding material 40. .

Even if it remains, it remains at a level where a slight air pocket is formed at the ridge line portion of the adjacent boundary 14c of each small lens molding concave surface 14b.
Thereby, in the case of this Embodiment 2, it can be set as the state which hardly leaves air on the surface (optical surface) of each small lens part 42a of the lens array 40B.

If the pressing by the pressure device 140 (upper plate 130) is stopped when the desired shape is transferred from the molding surface 14a to the plano-convex molding material 40, the molding of the lens array 40B is completed.
Also in the second embodiment, the shape of the substrate portion 41a of the lens array 40B exemplified in the above description, the shape and total number of the small lens portions 42a, the type of material glass, the plurality of small lens molding concave surfaces 14b in the upper mold 14 are formed. The arrangement, the shape of the plano-convex molding material 40, the order of the manufacturing process, and the like are not limited to the above-described examples.

The shape and total number of the small lens portions 42a can be changed according to the optical required performance for the lens array 40B.
In the lens array 40B, the substrate portion 41a and each small lens portion 42a are made of the same glass material, and the type of the glass material is not limited.

Further, in the mold assembly 10A, the small lens molding concave surface 14b may be formed not on the upper mold 14 but on the lower mold 12 side.
As long as the molding material has a convex curved surface, it may have a lens shape other than the plano-convex lens shape like the plano-convex molding material 40.

For example, a biconvex lens shape, a ball shape, a gob shape, a rod shape having a convex lens cross section, or a rod shape can be used.
According to the lens array manufacturing method of the second embodiment, with respect to the adjacent intersection 14d of the adjacent boundary 14c located at the array center of the plurality of small lens molding concave surfaces 14b arranged on the molding surface 14a of the upper mold 14, In the case where the surface center portion 43 of the plano-convex molding material 40 is disposed so as to abut, the relationship between the curvature radius Rp of the surface center portion 43 and the minimum curvature radius Ra of the small lens molding concave surface 14b is a relationship of Rp ≦ 2Ra. By setting the radius of curvature Rp so as to satisfy the requirements, it is possible to manufacture a lens array 40B of good quality that does not retain air even if it is molded using a single plano-convex molding material 40.

  Further, as a measure for preventing air accumulation during molding on the small lens molding concave surface 14b, a large-scale equipment such as a vacuum chamber or a vacuum evacuation process is unnecessary, and the cost is increased by adding extra equipment to the molding apparatus 100 and the manufacturing process. Productivity can be improved by suppressing an increase in necessary processing time.

  Further, in the case of the second embodiment, compared with the first embodiment described above, the restriction on the radius of curvature Rp of the convex surface 42 in the plano-convex molding material 40 is relaxed. There is also an advantage that the degree of freedom of shape is large.

Next, a modification of the second embodiment will be described with reference to FIGS. 8A, 8B, 8C, and 9. FIG.
In this modified example, a method of manufacturing a rectangular lens array by providing a deformation restricting portion in which the inner peripheral surface of the sleeve is set to an arbitrary shape and using a ball-shaped molding material as a molding material will be described.

  8A is a cross-sectional view showing the assembled state of the mold assembly at room temperature, FIG. 8B is a perspective view showing the shape of the molding surface of the upper mold, and FIG. 8C is a plane showing the shape of the molding surface of the upper mold. FIG. 9 and FIG. 9 are perspective views showing a rectangular lens array obtained in this modification.

First, the shape of the lens array 50A obtained in this modification will be described with reference to FIG. The substrate portion 52 of the lens array 50A has a parallel plate shape with a rectangular outline.
A plurality of small lens portions 53 are arranged in a lattice pattern at equal intervals on one surface of the substrate portion 52. The total number of small lens units 53 is 16 (4 × 4).

Next, the mold assembly 20 used in this modification will be described.
As illustrated in FIGS. 8A and 8B, the mold assembly 20 includes a sleeve 21, a lower mold 22, and an upper mold 23.

  The cross section of the through hole of the sleeve 21 to which the lower mold 22 and the upper mold 23 are fitted has a rectangular shape corresponding to the outline of the lens array 50A described above, and the inner peripheral surface is a rectangular deformation regulating surface 21a. Function.

  The outer peripheral shape of the insertion end with respect to the sleeve 21 on which the molding surface 23a and the molding surface 22a of the upper mold 23 and the lower mold 22 are formed is formed so as to be fitted to the inner circumferential surface (deformation regulating surface 21a) of the sleeve 21. In this example, it becomes a rectangular shape.

  In this case, as illustrated in FIG. 8B, for example, a plurality of 4 × 4 (L11 to L44) small lens molding concave surfaces 23b are adjacent to the entire surface of the rectangular molding surface 23a of the upper mold 23 in a lattice shape. An edge-shaped adjacent boundary 23c is formed between adjacent small lens molding concave surfaces 23b.

Further, the intersection of the adjacent boundary 23c at the center in the vertical and horizontal directions, that is, the adjacent intersection 23d (arrangement center) coincides with the central axis CZ of the molding surface 23a.
On the other hand, the molding surface 22a of the lower mold 22 is a rectangular flat surface.

  In the molding die assembly 20 of this modification, when a molding material is arranged on the molding surface 22 a of the lower die 22, a plurality of penetrating through the side wall surfaces of the sleeve 21 is prevented in order to prevent the arrangement state from becoming unstable. Jig hole 21b is provided.

A pin-shaped positioning member 25 (positioning means) is detachably mounted in each jig hole 21b by a method such as screwing.
The length of each positioning member 25 is set so that the distal end portion of the positioning member 25 is in contact with the molding material arranged at the center when inserted into the jig hole 21b.

  In this modification, for example, a spherical ball-shaped molding material 50 (molding material) is used as the molding material. The volume of the ball-shaped molding material 50 is matched with the volume of the lens array 50A to be manufactured.

  Similar to the second embodiment, the curvature radius Rp of the ball-shaped molding material 50 is set so as to satisfy the relationship of Rp ≦ 2Ra with respect to the minimum curvature radius Ra of the small lens molding concave surface 23b.

In addition, when the ball-shaped molding material 50 is spherical, an arbitrary portion on the outer periphery functions as the surface center portion 51 (top portion).
An assembly process in the mold assembly 20 of this modification will be described.

In a state where the lower mold 22 is fitted to the sleeve 21, the positioning member 25 is inserted into each of the jig holes 21 b provided on the side surface of the sleeve 21.
A ball-shaped molding material 50 is placed at the center of the molding surface 22a of the lower mold 22.

The ball-shaped molding material 50 placed at the center of the deformation regulating surface 21a is in contact with the tip of each positioning member 25, and the position is fixed and stabilized.
If the upper mold 23 is fitted to the sleeve 21 in this state, the mold assembly 20 in which the ball-shaped molding material 50 is sandwiched between the upper mold 23 and the lower mold 22 is obtained.

  Thus, in a state where the ball-shaped molding material 50 is sandwiched between the upper mold 23 and the lower mold 22, the adjacent intersection 23d (P2) located at the center and the apex (surface center portion 51) of the ball-shaped molding material 50 and Are in contact.

Further, the positioning member 25 inserted into each jig hole 21b is removed so as not to interfere with the subsequent molding process.
Next, the molding process of the mold assembly 20 assembled as described above will be described.

  When the mold assembly 20 is pressurized in a heated state to a predetermined molding temperature, the ball-shaped molding material 50 sandwiched between the lower mold 22 and the upper mold 23 is deformed, and between the molding surface 22a and the molding surface 23a. Fill the space part of.

  At this time, as in the case of the second embodiment, the ball-shaped molding material 50 spreads in close contact with the small lens molding concave surface 23b in the outer circumferential direction from the surface center portion 51 in contact with the central adjacent intersection 23d. The occurrence of accumulation is reliably prevented. Then, by transferring the shapes of the upper and lower molding surfaces 23a (small lens molding concave surface 23b) and the molding surface 22a, the substrate portion 52 and the plurality of small lens portions 53 of the lens array 50A are formed.

Further, since the inner peripheral surface of the sleeve 21 is used as the deformation restricting surface 21a, the deformation of the ball-shaped molding material 50 proceeds along the deformation restricting surface 21a.
As described above, the deformation regulating surface 21a of the sleeve 21 has a rectangular cross section, and when the deformed ball-shaped molding material 50 fills the space formed by the upper mold 23, the lower mold 22, and the sleeve 21, the molding is performed. The outer shape of the lens array 50A is rectangular.

If the pressing of the mold assembly 20 is stopped when the lens array 50A having a desired shape is obtained, the molding of the lens array 50A is completed.
Then, after a cooling process from the molding temperature to room temperature, a rectangular lens array 50A in which small lens portions 53 are arranged on one entire surface of the substrate portion 52 is obtained.

  In the mold assembly 20 of this modification, the lens array 50A having the substrate portion 52 having an arbitrary contour shape can be molded by using the inner peripheral surface of the sleeve 21 as the deformation regulating surface 21a.

  In addition, since the positioning member 25 can be mounted on the sleeve 21, for example, not only a spherical ball-shaped molding material 50 but also a molding material having an unstable arbitrary shape such as an egg shape, a rugby ball shape, or a gob shape can be used. The mold assembly 20 can be assembled by accurately and stably positioning the central axis CZ between the lower mold 22 and the upper mold 23.

  In this modification, the shape of the substrate portion 52, the shape and number of the small lens portions 53 exemplified in the above description regarding the lens array 50A, the type of material glass, and the upper mold 23 of the mold assembly 20 The arrangement of the small lens molding concave surface 23b, the shape of the molding material, the order of the manufacturing process, etc. are not limited to the above description.

For example, the shape of the deformation restricting portion constituted by the deformation restricting surface 21a of the sleeve 21 can be changed according to the outer shape of the substrate portion of the target lens array.
Moreover, although the number of the jig holes 21b and the positioning members 25 in which the positioning members 25 are mounted is set to four, two or more are sufficient.

  Next, as a further modification of the second embodiment, a case where a rod-shaped convex lens cross-section molding material 60 (molding material) is used instead of the ball-shaped molding material 50 in the molding die assembly 20 of the above-described modification will be described.

FIG. 10A is a perspective view illustrating an appearance of a convex lens cross-section molding material, and FIG. 10B is a perspective view illustrating an appearance of a lens array obtained from the convex lens cross-section molding material.
As illustrated in FIG. 10A, the shape of the convex lens cross-section molding material 60 is a rod shape, and the cross-section in the length direction of the rod is constant and has the shape of a convex lens cross section. That is, it has a so-called bowl shape in which a cylindrical surface 62 is provided on the opposite side of the flat bottom surface 61.

Therefore, the apex of the cylindrical surface 62 of the convex lens cross-section molding material 60 is a straight line parallel to the central axis CY direction, and the central portion is the surface central portion 63 (top).
The curvature radius Rp of the cylindrical surface 62 forming the convex lens cross section is set so as to satisfy the relationship of Rp ≦ 2Ra with respect to the minimum curvature radius Ra of the small lens molding concave surface 23b of the upper mold 23.

Further, the volume of the convex lens cross-section molding material 60 is matched with the volume of the lens array 60A to be manufactured.
Next, the assembly process of the mold assembly 20 when using the convex lens cross-section molding material 60 described above will be described.

In a state where the lower mold 22 is fitted to the sleeve 21, the positioning member 25 is inserted into each of the jig holes 21 b provided on the side surface of the sleeve 21.
A convex lens cross-section molding material 60 is placed on the center of the molding surface 22a of the lower mold 22.

The direction of the convex lens section molding material 60 is determined in accordance with the side direction of the rectangular deformation regulating surface 21a of the sleeve 21.
The convex lens cross-section molding material 60 placed at the center of the molding surface 22a is adjusted in position in contact with the tip of each positioning member, so that the position is fixed and stabilized.

If the upper mold 23 is fitted to the sleeve 21 in this state, the mold assembly 20 in which the convex lens cross-section molding material 60 is sandwiched between the upper mold 23 and the lower mold 22 is obtained.
At this time, inside the mold assembly 20, the surface center portion 63 of the convex lens section molding material 60 coincides with the adjacent intersection 23d (P2) of the plurality of small lens molding concave surfaces 23b of the upper mold 23, and the central axis CY. Are positioned so as to coincide with the central adjacent boundary 23c passing through the adjacent intersection 23d.

The positioning member 25 inserted into the jig hole 21b is removed so as not to interfere with the subsequent molding process.
Next, the molding process of the mold assembly 20 assembled as described above will be described.

  By pressing the mold assembly 20 at a desired molding temperature, the convex lens cross-section molding material 60 sandwiched between the lower mold 22 and the upper mold 23 is deformed, and the space between the molding surface 23a and the molding surface 22a is deformed. Will be filled.

In the initial stage of deformation, the softened convex lens cross-section molding material 60 is pushed outward from the position of the center bisector (that is, the center axis CY) including the adjacent intersection 23d (P2).
When the deformation of the convex lens cross-section molding material 60 proceeds, the substrate portion 61a and the plurality of small lens portions 62a of the lens array 60A are transferred to the convex lens cross-section molding material 60 to be formed.

Furthermore, since the inner peripheral surface of the sleeve 21 is the deformation restricting surface 21a, the deformation of the convex lens cross-section molding material 60 proceeds along the deformation restricting surface 21a.
As described above, the cross section of the deformation restricting surface 21a has a rectangular shape, and is formed when the convex lens cross-section molding material 60 is filled in the molding space formed by the upper mold 23, the lower mold 22, and the sleeve 21. The outer shape of the lens array 60A is rectangular.

If the pressing of the mold assembly 20 is stopped when a desired shape is obtained, the molding of the lens array 60A is completed.
Here, the effect of suppressing air retention when the convex lens cross-section molding material 60 is used will be described.

  When the small lens molding concave surface 23 b of the upper mold 23 is displaced in a direction approaching the lower mold 22, a closed space is not formed between the small lens molding concave surface 23 b and the cylindrical surface 62 of the convex lens section molding material 60. This will prevent the accumulation of air.

  In the cross-sectional direction including the convex portion (cylindrical surface 62) of the convex lens cross-section molding material 60, as described above, the curvature radius Rp satisfies the relationship of Rp ≦ 2Ra with respect to the minimum curvature radius Ra of the small lens molding concave surface 23b. ing.

  By satisfying this condition, in the deformation of the convex lens cross-section molding material 60, contact is made sequentially along the surface shape of each small lens molding concave surface 23b from the position of the center bisector (center axis CY) toward the outer circumferential direction. It is controlled to expand the range.

  In the direction orthogonal to the convex lens section (the direction of the central axis CY), it appears that a closed region is formed between the small lens molding concave surface 23 b and the cylindrical surface 62 of the convex lens section molding material 60. Since the top of the straight line coincides with the adjacent boundary 23c passing through the central adjacent intersection 23d, a closed space is not formed in a three-dimensional space.

  In each small lens molding concave surface 23b, the air existing inside is moved and excluded so as to be pushed out in the outer peripheral direction of the molding surface 23a along the flow of the deformed convex lens cross-section molding material 60.

Even if it remains, it remains at a level where a slight air pocket is formed at the ridge line portion of the adjacent boundary 23c of each small lens molding concave surface 23b.
As a result, almost no air remains on the optical surface of the small lens portion 62a of the lens array 60A molded from the convex lens section molding material 60.

Thereafter, when a cooling process to room temperature is performed, a rectangular lens array 60A as illustrated in FIG. 10B is obtained.
In this modification, the shape of the substrate portion 61a in the lens array 60A, the shape and number of the small lens portions 62a, the type of material glass, the arrangement of the small lens molding concave surface 23b in the upper mold 23, and the shape of the molding material The order of the manufacturing process and the like are not limited to the above-described examples.

For example, the rod-shaped molding material is not limited to the convex lens section molding material 60 described above as long as it has a convex curved surface in its cross section, and may be a cylindrical rod-shaped molding material.
Next, as still another modification, a manufacturing method for obtaining a lens array having a small lens portion of a semi-cylindrical surface using a rod-shaped molding material will be described.

  FIG. 11A is a plan view showing an arrangement state of a plurality of small lens molding surfaces composed of concave semi-cylindrical surfaces of the upper mold in this modification, FIG. 11B is a perspective view thereof, and FIG. 11C is a lens molded thereby. It is a perspective view which shows an array.

  As illustrated in FIG. 11C, the substrate portion 61a of the lens array 60B obtained in the present modification has a rectangular parallel plate shape. A plurality of cylindrical small lens portions 62b are arranged in parallel on one plane of the substrate portion 61a.

The number of cylindrical small lens portions 62b is six, and has a convex semi-cylindrical surface.
As the mold assembly for molding this lens array 60B, the above-described mold assembly 20 is used.

In this case, in the mold assembly 20, the upper mold 24 illustrated in FIGS. 11A and 11B is used in place of the upper mold 23 described above.
On the molding surface 24a of the upper mold 24, a plurality of small lens molding concave surfaces 24b (optical function concave surfaces) (L1 to L6) are arranged adjacent to each other at a predetermined pitch with the axial direction being parallel. An adjacent boundary 24c composed of a linear edge is formed between the adjacent small lens molding concave surfaces 24b.

Among the plurality of adjacent boundaries 24c, the center adjacent boundary 24d (array center) corresponds to the symmetry center of the plurality of small lens molding concave surfaces 24b in the arrangement direction.
The outer peripheral shapes of the upper mold 24 and the lower mold 22 are formed in a rectangular shape so as to fit into the rectangular inner peripheral surface (deformation regulating surface 21 a) of the sleeve 21.

In order to ensure the stability of the molding material after placement, a jig hole 21b and a positioning member 25 provided in the sleeve 21 are used.
As the molding material, the rod-shaped convex lens section molding material 60 illustrated in FIG. 10A is used.

  Here, the curvature radius Rp of the convex cylindrical surface 62 in the convex lens cross-section molding material 60 satisfies the relationship of Rp ≦ 2Ra with respect to the minimum curvature radius Ra of the small lens molding concave surface 24b in the upper mold 24. Set to

Next, the process of the above-mentioned mold assembly 20 and the convex lens section molding material 60 will be described.
In the assembly process of the mold assembly 20, the convex lens cross-section molding material 60 is arranged so that the direction of the convex lens cross-section (center axis CY) is parallel to the longitudinal direction of the small lens molding concave surface 24b at the center of the molding surface 24a. Deploy.

If the upper die 24 is fitted to the sleeve 21 in this state, the molding die assembly 20 in which the convex lens cross-section molding material 60 is sandwiched between the upper die 24 and the lower die 22 is obtained.
In the mold assembly 20 with the convex lens cross-section molding material 60 sandwiched in this way, the adjacent boundary 24c (E4) located at the center, that is, the central adjacent boundary 24d, and the surface of the cylindrical surface 62 of the convex lens cross-section molding material 60 A center line (center axis CY) passing through the center portion 63 is in line contact over the entire length.

  In the molding step of heating and pressurizing the mold assembly 20 to a desired molding temperature, the convex lens cross-section molding material 60 sandwiched between the lower mold 22 and the upper mold 24 is deformed, and between the molding surface 24a and the molding surface 22a. To fill the space.

  At this time, at the surface center portion 63 in line contact with the central adjacent boundary 24d of the convex lens cross-section molding material 60, the small lens molding concave surface 24b is formed between each small lens molding concave surface 24b according to the principle described in FIG. Since the deformation progresses while an open space is formed in the arrangement direction, the air inside the small lens molding concave surface 24b is not retained and is excluded outward in the arrangement direction of the small lens molding concave surface 24b. The occurrence of air pockets on the small lens molding concave surface 24b is prevented.

  When the deformation of the convex lens section molding material 60 proceeds in this way, the substrate surface 61a of the lens array 60B and the plurality of cylindrical small lens portions 62b are transferred by the transfer of the molding surface 24a, the small lens molding concave surface 24b, and the molding surface 22a. It is formed.

As described above, the cross section of the deformation restricting portion including the deformation restricting surface 21a of the sleeve 21 is rectangular, and the outer shape of the molded lens array 60B is rectangular.
If the pressing of the mold assembly 20 is stopped when the desired shape is obtained, the molding of the lens array 60B is completed.

Thereafter, when a cooling process to room temperature is performed, a rectangular lens array 60B as illustrated in FIG. 11C is obtained.
In this modification, the shape of the substrate portion 61a of the lens array 60B, the shape and number of the cylindrical small lens portions 62b, the type of material glass, the arrangement of the small lens molding concave surface 24b in the upper mold 24, the molding material The shape, the order of the manufacturing process, and the like are not limited to the above-described examples.

For example, the rod-shaped molding material is not limited to the convex lens section molding material 60 as long as it has a convex curved surface in its cross section, and may be, for example, a cylindrical rod-shaped molding material.
In each of the above-described embodiments, the case where the small lens portion or the cylindrical small lens portion is formed on one surface of the lens array is exemplified, but the lens array may be formed on both surfaces.

Hereinafter, a manufacturing method for obtaining a lens array in which small lens portions are arranged on both surfaces of a substrate portion using a biconvex lens-shaped molding material will be described.
FIG. 12A is a cross-sectional view showing a lens array in which convex small lens portions are arranged on both surfaces of a substrate portion, and FIG. 12B is a side view showing an example of a molding material used for molding this lens array. .

  The substrate portion 71a of the lens array 70A illustrated in FIG. 12A has a rectangular parallel plate shape. A plurality of small lens portions 72b and small lens portions 73b are formed on each of both surfaces of the substrate portion 71a in plane symmetry with respect to the central surface of the substrate portion 71a.

Each of the small lens portions 72b and the small lens portions 73b has a convex shape, and is formed of, for example, a spherical surface having a constant radius of curvature for each surface of the substrate portion 71a.
The number of small lens portions 72b and small lens portions 73b is 16 × 4 × 4 on one side of the substrate portion 71a and 32 in total on both sides.

  The plurality of small lens portions 72b and the small lens portions 73b are arranged in a square array at equal intervals on both surfaces of the substrate portion 71a, and the alignment direction and the center position are aligned on both surfaces. Thereby, for example, the optical axes of the corresponding small lens portion 72b and the small lens portion 73b coincide with each other.

Needless to say, the necessary optical functions may be realized by intentionally disposing the corresponding small lens portions 72b and 73b.
As the mold assembly, the above-described mold assembly 20 can be used. However, in this case, the lower mold 26 is used instead of the lower mold 22. As shown in FIG. 8B, the lower mold 26 is formed with a small lens molding concave surface 26b (optical functional concave surface) (molding surface 26a) similar to the upper mold 23.

  That is, on the molding surface 23a and molding surface 26a of each of the upper mold 23 and the lower mold 26, there are 16 small lens molding concave surfaces corresponding to the small lens portions 73b and the small lens portions 72b on both surfaces of the lens array 70A. 23b and a small lens molding concave surface 26b are formed.

Regarding the arrangement of the small lens molding concave surface 23b and the small lens molding concave surface 26b of each of the upper mold 23 and the lower mold 26, it is necessary to match the arrangement direction.
In the case of the upper mold 23 and the lower mold 26 that are fitted to the rectangular deformation regulating surface 21a as in the mold assembly 20, the positions of the upper and lower small lens molding concave surfaces 23b and the small lens molding concave surface 26b are automatically set. Matching is done.

  When the deformation regulating surface 21a is circular, a guide shape (not shown) is provided on the sleeve 21 side as means for aligning the arrangement direction of the small lens molding concave surfaces 23b in each of the upper mold 23 and the lower mold 26. It is conceivable to provide a key shape (not shown) that fits in the guide shape on the 23 and the lower die 26.

In the case of the mold assembly 20 described above, the rectangular outer shape of the upper die 23 and the lower die 26 and the rectangular deformation regulating surface 21a of the sleeve 21 function as a key shape and a guide shape.
In this case, a biconvex molding material 70 (molding material) as illustrated in FIG. 12B is used. The biconvex molding material 70 has a shape in which a convex surface 72 and a convex surface 73 made of, for example, a spherical surface are provided at both ends of a cylindrical body 71. The volume of the biconvex molding material 70 is matched with the volume of the lens array 70A to be manufactured.

Radius of curvature _Rp 1, Rp ₂ spherical convex surface 73 and a convex surface 72 at both convex forming material 70, the molding surface 23a of the upper die 23 and lower die 26 corresponding, small arranged on the molding surface 26a The minimum curvature radii Ra ₁ and Ra _{2 of the} lens molding concave surface 23b and the small lens molding concave surface 26b are set so as to satisfy the following expression (3).
Rp ₁ ≦ 2Ra ₁ and Rp ₂ ≦ 2Ra ₂ , (3)

Next, the assembly process of the mold assembly 20 including the upper mold 23 and the lower mold 26 as described above will be described.
In the assembly process of the molding die assembly 20, the biconvex molding material 70 is arranged so that the surface central portion 72a (top portion) coincides with the central portion (P3 in FIG. 8C) of the molding surface 26a of the lower die 26.

If the upper mold 23 is fitted to the sleeve 21 in this state, the molding die assembly 20 in which the bi-convex molding material 70 is sandwiched between the upper mold 23 and the lower mold 26 is obtained.
In this assembled state, the adjacent intersection P2 (P3) located at the center of the molding surface 23a (molding surface 26a) of the upper die 23 (lower die 26) and the surface center portion 73a (surface center portion) of the biconvex molding material 70 72a) (top) is in contact.

Next, the molding process of the mold assembly 20 including the upper mold 23 and the lower mold 26 described above will be described.
When the mold assembly 20 heated to a desired molding temperature is pressurized, the biconvex molding material 70 sandwiched between the lower mold 26 and the upper mold 23 is deformed, and between the molding surface 23a and the molding surface 26a. Fill the space.

  At this time, the convex surface 72 and the convex surface 73 of the biconvex molding material 70 correspond to the above-described formula (3) with respect to the corresponding small lens molding concave surface 26b of the lower mold 26 and small lens molding concave surface 23b of the upper mold 23. ) Is set in a shape that satisfies the condition (2), the small lens molding concave surface 26b and the small lens molding concave surface 23b provided in each of the lower mold 26 and the upper mold 23 are in accordance with the principle described in FIG. Is eliminated outwardly from the adjacent intersection P3 (P2) located at the center of the molding surface 26a and the molding surface 23a, so that air pockets are prevented from occurring on the small lens molding concave surface 26b and the small lens molding concave surface 23b. The

  When the deformation of the biconvex molding material 70 proceeds, the substrate portion 71a, the plurality of small lens portions 72b, and the small lens portions 73b of the lens array 70A are transferred from the lower mold 26 and the upper mold 23 to be formed.

If the pressing of the mold assembly 20 is stopped when the desired shape is obtained, the molding of the lens array 70A is completed.
Then, after passing through the cooling step to room temperature, a rectangular lens array 70A illustrated in FIG. 12A is obtained.

The same effect can be obtained by setting the curvature radii of the convex surface 72 and the convex surface 73 of the both convex molding materials 70 to the same curvature radius Rp and satisfying the following equation (4). It is done.
Rp ≦ 2Ra ₁ and Rp ≦ 2Ra ₂ , (4)

  In this modification, the shape of the substrate portion 71a of the lens array 70A described above, the shape and number of the small lens portions 72b and the small lens portions 73b, the type of material glass, and the small size in the upper mold 23 and the lower mold 26 are used. The arrangement of the lens molding concave surface 23b and the small lens molding concave surface 26b, the shape of the biconvex molding material 70, the order of the manufacturing process, and the like are not limited to the above disclosure.

For example, the shape and number of the small lens portions can be changed according to the required performance, and are not limited to the above-described contents.
There are no restrictions on the guide shape and the key shape used as means for aligning the arrangement directions of the small lens molding concave surface 23b and the small lens molding concave surface 26b of the upper mold 23 and the lower mold 26, and various shapes can be used.

The shape of the molding material is not limited to the biconvex molding material 70 described above, but may be a ball shape, a gob shape, a rod shape with a biconvex lens cross section, or a rod shape.
As described above, according to each embodiment of the present invention, by devising the shape of the molding material, a lens array of good quality that does not retain air even when molded using a single molding material. Can be manufactured.

  Furthermore, it is possible to eliminate the need for a vacuum apparatus and a vacuum state during molding, which are conventionally required, and to suppress an increase in cost due to the addition of a manufacturing apparatus and an increase in processing time required in the manufacturing process.

  That is, there is no need for large-scale manufacturing equipment, and there is no increase in cycle time or manufacturing cost in the molding process, and there is no restriction on the shape of the lens array. It is possible to reliably prevent the occurrence and to manufacture a lens array with stable quality with high productivity and low cost.

  Needless to say, the present invention is not limited to the configuration exemplified in the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

(Appendix 1)
In a method of manufacturing a lens array in which a single molding material is molded with an upper mold and a lower mold, and an array of a plurality of small lens sections having a convex shape is arranged on at least one surface of a substrate section,
Each of the upper mold and the lower mold has a molding surface, and at least one of the upper mold and the lower mold is provided with a small lens molding surface corresponding to each of the plurality of small lens portions,
The surface of the molding material has a convex curved surface,
A step of aligning the center of the surface of the molding material with the center of the molding surface provided with the small lens molding surface and incorporating it between the upper mold and the lower mold;
Pressing the heat-softened molding material with the upper mold and the lower mold to mold the lens array so as to be deformed from the center direction to the outer circumferential direction;
A method of manufacturing a lens array, comprising:

(Appendix 2)
The molding surface having a plurality of small lens molding surfaces is arranged such that the top of the small lens molding surface located at the center of the array of the small lens molding surfaces is aligned with the center of the molding surface,
The plurality of small lens molding surfaces have concave curved surfaces, and when the minimum curvature radius of each curved surface is Ra,
The molding material has a curved surface with a radius of curvature Rp,
The curvature radius Rp is set so that the relationship with the minimum curvature radius Ra satisfies Rp ≦ Ra.
The method for manufacturing a lens array according to appendix 1, wherein:

(Appendix 3)
The molding surface having a plurality of small lens molding surfaces is arranged in such a manner that the adjacent portion formed by the adjacent small lens molding surfaces is positioned in the center of the array of the small lens molding surfaces with respect to the central portion of the molding surface. And
Each small lens molding surface has a concave curved surface, and when the minimum curvature radius of each curved surface is Ra,
The molding material has a curved surface with a radius of curvature Rp,
The curvature radius Rp is set so that the relationship with the minimum curvature radius Ra satisfies Rp ≦ 2Ra.
The method for manufacturing a lens array according to appendix 1, wherein:

(Appendix 4)
The lens array is arranged with an array of a plurality of small lens parts having convex shapes on both sides of the substrate part,
In the assembling process, the center part of the molding surface of the upper mold and the center part of the molding surface of the lower mold are on the same axis, and the arrangement of the small lens molding surfaces of the upper mold and the small lens molding surfaces of the lower mold are Arrangement is aligned with the arrangement direction,
The method for manufacturing a lens array according to any one of supplementary notes 1 to 3, wherein:

(Appendix 5)
Between the upper mold and the lower mold, provided with a deformation regulating portion for regulating the deformation state of the heat-softened molding material to obtain a desired outer shape,
The method for manufacturing a lens array according to any one of appendices 1 to 4, wherein:

(Appendix 6)
The material of the molding material is optical glass,
The method for manufacturing a lens array according to any one of appendices 1 to 5, wherein:

(Appendix 7)
The shape of the molding material is either a ball shape, a convex lens shape, a rod shape, or a rod shape having a convex lens cross section,
The method for manufacturing a lens array according to any one of appendices 1 to 6, wherein:

(Appendix 8)
The volume of the molding material matches the volume of the lens array.
The method for manufacturing a lens array according to any one of appendices 1 to 7, wherein:

DESCRIPTION OF SYMBOLS 10 Mold assembly 10A Mold assembly 11 Sleeve 12 Lower mold 12a Molding surface 13 Upper mold 13a Molding surface 13b Small lens molding concave surface 13c Concave surface vertex 13d Adjacent line 14 Upper mold 14a Molding surface 14b Small lens molding concave surface 14c Adjacent boundary 14d Adjacent intersection 20 Mold assembly 21 Sleeve 21a Deformation restriction surface 21b Jig hole 22 Lower mold 22a Molding surface 23 Upper mold 23a Molding surface 23b Small lens molding concave surface 23c Adjacent boundary 23d Adjacent intersection 24 Upper mold 24a Molding surface 24b Small lens molding Concave surface 24c Adjacent boundary 24d Center adjacent boundary 25 Positioning member 26 Lower mold 26a Molding surface 26b Small lens molding concave surface 40 Plano-convex molding material 40A Lens array 40B Lens array 41 Bottom surface 41a Substrate portion 42 Convex surface 42a Small lens portion 43 Center of surface 50 Ball-shaped molding material 50A Lens array 0B Lens array 51 Surface central part 52 Substrate part 53 Small lens part 60 Convex lens cross-section molding material 60A Lens array 60B Lens array 61 Bottom surface 61a Substrate part 62 Cylindrical surface 62a Small lens part 62b Cylindrical small lens part 63 Surface central part 70 Biconvex Molding material 70A Lens array 71 Body 71a Substrate part 72 Convex surface 72a Surface center part 72b Small lens part 73 Convex surface 73a Surface center part 73b Small lens part 100 Molding device 110 Molding stage 120 Lower plate 121 Heater 130 Upper plate 131 Heater 140 Pressurizing device

Claims (3)

Positioning so that the tops of the convex shaped molding materials coincide with the arrangement center of the plurality of optical functional concave surfaces arranged on at least one molding surface of the upper mold and the lower mold; and
Clamping the molding material between the molding surfaces of the upper mold and the lower mold, and deforming the molding material so that the molding material spreads in the peripheral direction from the center of the arrangement; and
Including
A plurality of the optical function concave surfaces are arranged on the molding surface such that a boundary portion between the adjacent optical function concave surfaces coincides with the arrangement center,
The shape of the molding material is set to satisfy Rp ≦ 2Ra, where Ra is the minimum curvature radius of each concave surface of the optical function and Rp is the curvature radius of the top of the molding material. A method of manufacturing a lens array. In the manufacturing method of the lens array of Claim 1,
The minimum curvature radius Ra _{1 of the} optical function concave surface arranged on the molding surface of the upper mold is different from the minimum curvature radius Ra _{2 of the} optical functional concave surface arranged on the molding surface of the lower mold,
When the plurality of optical function concave surfaces are arranged on the molding surfaces of the upper mold and the lower mold so that the boundary portion of the adjacent optical function concave surfaces coincides with the arrangement center,
The curvature radii Rp ₁ and Rp ₂ of each of the two top portions corresponding to the arrangement center of the molding surface of each of the upper mold and the lower mold of the molding material are Rp ₁ ≦ 2Ra ₁ and Rp ₂ ≦ 2Ra. _{2. A} method of manufacturing a lens array satisfying ₂ . In the manufacturing method of the lens array of Claim 1 or Claim 2,
When the plurality of optical functional concave surfaces each consisting of a semi-cylindrical surface are arranged on the molding surface with the axial direction of the semi-cylindrical surface being parallel,
A method of manufacturing a lens array, comprising arranging a rod-shaped or rod-shaped molding material having a convex lens cross section in parallel with an axial direction of the semi-cylindrical surface.