JPH01107204A - Molding method for lens array - Google Patents

Abstract

PURPOSE:To mold a lens array which has high accuracy and is optically nondirectional in a short time by transferring molding surfaces of an upper and a lower punch array to a heat-welded member to be worked. CONSTITUTION:The upper and lower punch arrays 17 and 18 are vibrated in opposite-phase relation and each body 30 to be molded is heated and softened with shearing heat generated by said vibration. Then the body 30 to be molded is vibrated and pressed by upper and lower molding actuators 15 and 16 through the upper and lower punch arrays 17 and 18. The shapes of the molding surfaces 17a and 18a of the upper and lower punch arrays 17 and 18 are transferred to the body to be molded which is heated and softened by said vibration pressing process respectively and adjacent bodies to be molded are heat-welded to mold a lens array in a desired shape. Consequently, the lens array which has high accuracy and is optically nondirectional is molded in a short time by the simple mold constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for molding a lens array used for optical coupling of imaging lens optical fibers of copying machines.

[Conventional technology]

As a method for processing this kind of lens array mentioned above, G
Except for the RIN lens, it is unclear whether it is made of plastic mold. There are two methods for molding a lens array using such a plastic mold: (1) injection molding, (2) hot press molding,
Various proposals have been made regarding such techniques.
It is disclosed in the publication No.-95912.

The technique disclosed in Japanese Patent Application Laid-Open No. 61-95912 is such that a lens material is placed on a pair of molds each having a through hole on at least one lens material pressing surface, and the lens material is placed in a predetermined moldable mold. By press-molding the lens material through the mold while heated to a temperature, the lens material is extruded into the through-hole, and then cooled and solidified so that the surface shape of the lens material becomes a desired lens. It is molded to have a certain shape.

[Problem that the invention seeks to solve]

However, the conventional lens array molding method described above has the following problems. That is, first, the method based on injection molding has the problem of high cost because it requires a large investment in equipment for molding molds and molding equipment. In addition, in the injection molding process, in order to cool and harden the molded product by flowing molten resin from the sprue of the mold,
There is a problem in that the flow of the resin causes directionality in the lens surface shape and the refractive index within the lens, resulting in the production of a lens array that is unfavorable in terms of optical performance.

In addition, the method using hot extrusion molding does not cause directionality in the lens surface shape or the refractive index within the lens due to the resin flow as in the injection molding method described above, but it molds a lens array with good optical performance. This poses a problem in that a long molding time is required and the molding cycle time becomes extremely long. In addition, in the hot pressing method, in order to mold a plate-shaped blank into a convex lens shape,
Air is likely to be trapped in the space formed between the blank and the mold, and if this air is poorly vented, there is a problem in that abnormalities occur on the optical surface of the molded product. Therefore, for this reason, the technique disclosed in the above-mentioned Japanese Patent Application Laid-open No. 617-95912 has the problem that it is not possible to obtain a lens array having a highly accurate surface shape, and the range of application is extremely narrow. .

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to produce a high-precision lens array with no optical directionality (isotropic) using a simple device and a short molding time. An object of the present invention is to provide a method for molding a lens array.

[Means and effects for solving the problem] The present invention provides a method for supplying and sandwiching a plurality of workpieces between upper and lower punch arrays having lens array forming surfaces, and then inserting the upper and lower punch arrays. is vibrated to heat-soften each of the workpieces through shear caused by the vibration, and the upper and lower punch arrays press the workpieces to separate them from each other or between the workpieces and the workpiece. By thermally welding the workpiece support frame to the workpiece support frame using vibration shear insulation to form an array, and by transferring the molding surfaces of the upper and lower punch arrays to the heat-welded workpiece, optical orientation can be achieved with high precision. This makes it possible to mold a neutral lens array in a short time.

[Examples] Examples of the present invention will be described in detail below, using drawings as necessary.

(First Embodiment) FIG. 1 is an explanatory cross-sectional view of a lens array molding apparatus l for carrying out a lens array molding method according to the present invention.

In the figure, 2 indicates a support base (fixed base) for the molding device 1, and this support base 2 has upper and lower vibration actuators 3.
．． An upper excitation frame 5 and a lower excitation frame 6 are installed via the frame 4 so as to be able to excite freely.

The upper excitation frame 5 is formed with mutually parallel sliding shaft portions 7 and 8, and each of the sliding shaft portions 7 and 8 is connected to a guide hole 9 recessed in the lower excitation frame 6 side. .10 is slidably inserted. A spring bearing part 11.12 is formed in each of the tW moving shaft part 7.8 and the guide hole parts 8, 10, and each spring bearing has an elastic force such as a compression coil spring between the parts 11.12. 13.14 is loaded. The axes of the sliding shafts 7 and 8 and the guide holes 9 and 10 are aligned with the upper and lower vibration actuators 3.
．． It is set in the same direction as the vibration direction by the vibration actuator 3.4, and when the vibration is driven via the vibration actuator 3.4, the
3. Due to the action of 14, the sliding shaft parts 7, 8 and the guide hole part 9,
It is set so that sliding with 1o can be performed smoothly.

A lower molding actuator 15 and a lower molding actuator 16 are fixedly attached to the upper and lower vibration frames 5 and 6, respectively, and molding surfaces 17a and 18a are provided at the ends of each actuator 15 and 16. Upper punch array with 17. The lower punch arrays 18 are each attached. The punch arrays 17 and 18 are arranged facing each other on the same axis, and are configured to be freely movable and driven in the axial direction via respective forming actuators 15 and 16. The upper and lower vibration actuators 3.4 and the upper and lower forming actuators 15.16 are connected to the hydraulic control device 23 via oil pipes (hydraulic control pipes) 19.20.21.22, The upper and lower punch arrays 17 and 18 are configured to be able to be controlled to operate in opposite phases, that is, in directions toward and away from each other, via a hydraulic control device 23.

Molding surface 17a of each punch array 17, 1B.

18a may be formed on the molding surface 17a (or 18a) on which a single row of lens arrays can be molded, as shown in FIG. 2a, or a matrix-like lens array can be formed as shown in FIG. Molding surface 17a (or 18a) that can be molded
It may be formed into

Next, a method of molding a lens array using the lens array molding apparatus 1 having the above configuration will be described.

First, top and bottom punch array 17.18.

They are moved away from each other via the lower shaping actuators 15,16.

Next, the object to be formed (
A predetermined number of workpieces 30 (see FIG. 3a) are supplied and placed. In this example, spherical bodies (beads) made of thermoplastic resin were used as objects to be molded, as shown in FIG. 3a.

Next, the upper punch array 17 or/and the lower punch array 1
8 is actuated via the lower molding actuator 15 and/or the lower molding actuator 16 to sandwich each molded object 30.

Next, operate the upper and lower vibration actuators 3.4,
Upper, lower via excitation frame 5.6.

Vibrate the lower punch array 17 and 18. During this vibration operation, the upper and lower punch arrays 17 and 18 are vibrated with opposite phases of vibration, and each molded object 30 is thermally softened by the shear heat generated by the vibration. And further up,
The molded object 30 is pressed through the upper and lower punch arrays 17.18, which are subjected to pressure by the lower molding actuator 15.16.
is vibrated and pressurized. In this vibration pressing step, the shapes of the molding surfaces 17a and 18a of the upper and lower punch arrays 17 and 18 are transferred to the heat-softened molded object 30, respectively, and
As shown in FIG. 3ab, adjacent molded objects are heat-sealed to form a lens array 31 having a desired shape as shown in FIG. 3(a).

As described above, according to the molding method of this embodiment, the only molds required for molding are the upper and lower punch arrays 17 and 18, which greatly simplifies the molding equipment, reduces equipment investment, and reduces molding costs. It is possible to reduce the cost of products. Furthermore, since there is no flow of resin as in injection molding, the lens array 31 can be molded without optical directionality. In addition, due to the shear heat caused by vibration, the area near the cavity (molding surface 17a) is locally reduced.

18a), the molding cycle time can be extremely shortened, and productivity and production efficiency can be improved. Furthermore, since this is a method of thermally softening and molding the spherical to-be-molded object 30, the molding surface 17a during molding is
, 18a and the molded object 30 (as a result, the lens array 31 having a highly accurate surface shape can be molded).

(Second Embodiment) FIGS. 4a and 4b show an apparatus for implementing a second embodiment of the lens array molding method according to the present invention.

In this embodiment, a plurality of spherical objects 30 formed by upper and lower punch arrays 17 and 18 are placed in a frame 30 having a plurality of holes 32 formed with a diameter suitably smaller than that of the objects 30 to be formed.
The molding is performed by supporting each of the three famous flowers 32. The name flower 32 in the frame 33 is arranged so that each supported molded object 30 is placed in the upper and lower punch arrays 17 during molding.
18 molding surfaces 17a, 18a at a predetermined pitch. Since the other configurations are the same as those of the first embodiment, illustration and description thereof will be omitted.

The molding process of this example is similar to that of the first example, but according to this example, each molded object 30 is
The lens array 31 is molded with the lens array 31 being welded to the frame 33 as shown in FIG. The lens array 31 after molding may be in a state in which adjacent molded objects 30 are welded to each other, but there is no particular need to be in a welded state, and each molded object 30 is welded to the frame 33 as described above. It is sufficient if it is molded in the same state.

According to this embodiment, since the frame 33 serves as a support for the object to be formed 30, the forming process becomes easier. In addition, it is possible for the frame 33 to maintain its function as a light-shielding frame, and if holes for mounting and fixing other components are provided on the outer circumference of the frame 33, mounting and fixing to other components is facilitated. There are advantages. Other effects are the first
Since this is the same as the embodiment, the explanation thereof will be omitted.

In addition, in each of the above embodiments, a plurality of spherical to-be-molded objects 3
Although the spherical molded objects 30 may be molded using a single material, for example, materials with different refractive indexes such as PMMA and polycarbonate may be mixed. The lens array 31 may be molded using the same method.

By setting and molding as described above, the lens array 31 useful for displaying differences in focus position can be highly functional. Furthermore, even if the basic physical properties are the same, it is possible to easily change the spectral transmittance by changing the additives.

Therefore, if the display section is colored, there is an advantage that special mounting, frames, and adjustments for equal spacing are not required.

In addition, in each of the above embodiments, only an example in which a biconvex lens is molded has been mainly described, but the invention is not limited to this example. It can also be applied when molding lenses. Further, the front surface 71 of the lens array 31 is not limited to a spherical surface or a flat surface, but can also be applied to the molding of lens surfaces such as toric surfaces such as cylindrical surfaces, and spherical surfaces.

Further, although only spherical objects are shown as the object to be formed 30, objects other than spherical objects, such as cylindrical pellets as shown in FIGS. It can also be applied to objects of any shape.

〔Effect of the invention〕

As described above, according to the present invention, a lens array with high precision and no optical directionality can be molded in a short time with a simple mold configuration.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a molding apparatus for carrying out the first embodiment of the method according to the present invention, FIGS. 2 a and b are explanatory diagrams of a lens array molding surface, and FIGS. 3 a and b are FIGS. 4a and 4b are explanatory views showing the forming process of the second embodiment of the method according to the present invention. FIGS. 5a and b are explanatory views showing the forming process of the second embodiment of the method according to the present invention. FIGS. It is a process explanatory diagram which shows an example. 3.4... Vibration actuator 15.16... Molding actuator 17.18... Upper and lower punch arrays 17a, 18a
... Molding surface 30 ... Workpiece member 31 ... Lens array 33 ... Frame Fig. 1 77a (18a) (a) Fig. 3 (b) Fig. 5 (a: (t)) Showa December 1, 1962 Kunio Ogawa, Commissioner of the Patent Office2, Title of the invention: Lens array molding method 3, Relationship to the person making the amendment case Patent applicant address: 2-43-2 Hatagaya, Shibuya-ku, Tokyo Name
(037) Representative of Olympus Optical Industry Co., Ltd.
Toshi Yamabe 4, Agent 105 Address 2-2-15 Hamamatsucho, Minato-ku, Tokyo "
Column 7 of ``Detailed Description of the Invention'', Contents of Amendment (1) The ``spherical surface'' described on page 12, line 14 of the specification is amended to be ``aspherical surface''.

Claims (1)

[Claims] (1) A plurality of workpieces are supplied and sandwiched between upper and lower punch arrays having lens array forming surfaces, and then the upper and lower punch arrays are vibrated to vibrate each workpiece. It is thermally softened by shear insulation,
Furthermore, the above-mentioned upper and lower punch arrays press the respective workpieces to thermally weld the workpieces together or the workpieces and the workpiece support frame by vibration shear heat insulation, thereby forming an array; A method for molding a lens array, characterized in that the molding surfaces of the upper and lower punch arrays are transferred to the heat-welded workpiece.