JP2002293553A - Method for producing optical element, production apparatus and molding raw material of optical element, mold for premolding and lens array of optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an optical element, with which occurrence of non-transcribed part due to existence of residual space at the interface between a plate-like forming raw material and a concave molding mold is reduced, or eliminated particularly in case of molding a lens array of optical elements, to provide a production apparatus for obtaining a lens array of the optical elements using a plate-like glass material, a method for producing an optical element using the, a molding material, a premolding mold. SOLUTION: This method for producing an optical element comprises molding a preliminary molded product having a convex shape with a pseudo-mirror face or pseudo-cylindrical face to avoid the residual space for a plate-like glass material by providing a preheating part Q1 and a premolding part Q2 in the course of a continuous production process. The lens array of the optical elements is obtained by regular molding of the premolded product at a regular molding part Q3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element mainly used for an illumination optical system of a projector using a halogen lamp, a metal halide lamp or the like as a light source. In the illumination optical system, a lens array is used as an optical element aiming at improvement of light use efficiency, improvement of brightness, improvement of color unevenness, and the like. Is a particularly suitable target. However, it is not necessary to limit the present invention to only the lens array, and it can be widely applied to any type of optical element.

[0002] The present invention also relates to a method and apparatus for manufacturing an optical element represented by a lens array. Further, the present invention relates to a preforming mold and a molding material for an optical element.

[0003]

2. Description of the Related Art FIG. 10 explains the principle of an illumination optical system in a liquid crystal projector using a lens array as the above optical element. The parallel rays emitted from the luminous body S of the lamp 71 using a halogen or metal halide as a light source are as follows.
After passing through the first lens 73 of the first lens array 72, the second lens
The light is condensed on the main plane of the second lens 75 of the lens array 74 to form a real image of the light emitter S, that is, a light emitter image S ′. Thereafter, the light that has passed through the second lens array 74 is uniformly applied to the liquid crystal panel surface P ′. Therefore, the first lens array 72 acts as one that is focused on the main plane of the second lens array 74 to form a real image of the illuminant, and the second lens array 74 The light beam incident on the liquid crystal panel is enlarged according to a predetermined magnification, and functions as light for illuminating the liquid crystal panel, which is the illuminated area.

[0004] There are the following two methods as conventional typical methods for manufacturing the optical element of the lens array as described above.

(1) A direct press method in which a molten and softened glass block is directly supplied into a mold having an optical function surface to form an optical element.

(2) A reheat molding method in which a molding material is molded into an optical element using a mold having a predetermined optical function surface and a glass preform under conditions in which both are at an isothermal and relatively low temperature.

In the above, all require a molding die having an optically functional surface, and the shape of the optically functional surface is transferred to a glass material.

However, in the above method (1), since the glass material supplied at the time of molding is high in temperature and the molding die is relatively low in temperature, the amount of shrinkage caused by the temperature difference between the two is too large, so Large thermal distortion and sink marks occur, making it difficult to precisely transfer the shape of the optically functional surface.
The generated thermal strain requires an annealing treatment, and has a complexity such that secondary processing by optical polishing or the like is required to avoid sink marks.

Further, since the molding is performed at a high temperature and usually in the atmosphere, the oxidation of the mold progresses. Therefore, it is necessary to perform the mold maintenance periodically. There is a risk that the shape of the functional surface will be damaged.

[0010] Since the mold is opened in a high temperature state where the glass material is not cooled, the mold releasability is good and the molding cycle time is relatively short.

On the other hand, the method (2) uses a molding die having a molding surface which is expensive but has excellent mold releasability, protects the mold from oxidation, and releases the molding material from a glass material. In order to stabilize the properties, it is common to perform pressure molding in a chamber filled with an inert gas. Normally, near the yield point of glass material (glass transition point + 100 ° C or less)
The molding is possible at a relatively low temperature and at the same temperature as the molding die. Due to the low temperature, the amount of shrinkage of the glass material is extremely small, and the mold releasability between the molding surface and the glass material is good, so it is possible to press down to the minimum temperature of the plastic deformation area and obtain precise transferability. And low thermal distortion. Therefore, there is no need for secondary processing or annealing.

On the other hand, because of the isothermal molding, it is difficult to shorten the cycle time required for raising and lowering the temperature between the room temperature and the molding temperature in the glass material. For that purpose, a large number of expensive molds that constitute a precisely processed optical functional surface must be used, and there are restrictions on the material shape of the glass to be supplied and cost problems.

FIG. 9 shows a molding method that can be considered with reference to the above-mentioned conventional method (2).

A molding material 64 is put into a molding die composed of a lower die 61, an upper die 62 and a body die 63, and the entire molding die is heated in an inert gas to form a molding material 64 made of a glass material. At the yield point or above and at the time when the temperature reaches a deformable temperature. In the upper mold 62 and the lower mold 61, a desired number of flat surfaces and a plurality of concave shapes of the optical function surface are precisely machined on the surfaces in contact with the molding material 64. In this case, the upper mold 62 having a flat optical function surface can be obtained at a low cost, but the lower mold 61 requires an extremely large number of processing man-hours instead of the ratio, and is therefore expensive.

As the shape of the molding material 64 to be supplied, a flat plate-shaped material has the best heating efficiency, and the amount of pressing deformation during molding is small, so that molding can be performed in a short time. Also, it is suitable for reheat molding because it can be easily obtained at low cost.

[0016]

However, there is a possibility that a residual space 65 is formed between the concave surface of the lower mold 61 and the flat surface of the molding material 64 so that the plastic deformation portion of the molding material does not enter. That is, an untransferred portion remains on the convex surface side of the optical element 64 to be molded, and the function as the optical element cannot be performed. Such a problem is unlikely to occur in the method (1), and therefore, the current technology (1)
Is the mainstream method. However, the method of (1) also
There are many problems as described above.

The present invention has been made in order to solve the above-mentioned problems, and eliminates the occurrence of untransferred portions due to the residual space even when a flat glass material having high thermal efficiency is used as a molding material. An object of the present invention is to provide a manufacturing method and a manufacturing apparatus which enable precise transfer on all optical functional surfaces of an array of optical elements and do not require secondary processing. Another object of the present invention is to provide an inexpensive lens array optical element by minimizing the required number of expensive molding dies and shortening the molding cycle time.

[0018]

Means for solving the problems in the method of manufacturing an optical element according to the present invention are as follows. Prepare a molding block in which the fitted lower mold, body mold and molding material made of flat glass material are integrated, and the molding material can be deformed by pressing by preliminarily heating the entire molding block. Preheat to a suitable temperature. Thereafter, the molding block is transported to a preforming step, and the molding material of the glass material is pressed by using a preforming mold having a plurality of recesses formed on a molding surface, and a plurality of projections are formed on the surface of the molding material. To form After the pressing is released, the molding block is transported to the main molding step, and the molding is completed by pressing again using the main molding die on which the desired optical functional surface is arranged in an array. After releasing the pressing, the molded block is transported to a cooling step to cool the entire molded block, and then the molded block is disassembled and the lens array optical element is taken out.

Even in the case of a flat forming material in the preforming, a plurality of convex portions are preliminarily formed on the surface thereof, so that the untransferred portion due to the remaining space, which is a conventional problem, is not formed. In the main molding step, it is possible to precisely transfer the entire optically functional surface.

The solution of the optical element molding apparatus according to the present invention is as follows. A molded block composed of a lower mold, a body mold, and a molding material placed on the lower mold that are fitted to each other with a taper will be handled. A pre-heating portion capable of heating the entire forming block, a pre-forming portion including a pre-forming die capable of heating and pressing the forming block, and a main forming die having a concave optical function surface formed in an array And a cooling unit for cooling the entire molding block, the main molding unit being capable of applying heat and pressure to the molding block. Then, the four parts are contained in a chamber. In the chamber, there is provided conveying means for sequentially conveying the forming block to each of a pre-heating unit, a pre-forming unit, a main forming unit, and a cooling unit. The chamber is provided with an inlet and an outlet having a shutter that can be opened and closed for loading and unloading the molding block into and out of the chamber, and a gas inlet for feeding an inert gas into the chamber. With this configuration, the number of expensive mold surfaces can be reduced. Further, only the molding block can be transported, and the cycle time can be reduced. Then, an inexpensive optical element can be provided as a whole.

In a preferred embodiment of the above-mentioned optical element manufacturing apparatus, the pre-forming section and the main forming section each include an upper heating plate,
There is a configuration in which a stripper pin is provided on a side of the upper heating plate to assist in releasing the preforming mold or the main molding die from the molding block. Parting of the preforming die or the main forming die into the forming material in the forming block causes resistance at the time of release, but the stripper pin resists the separation of the preforming die or the main forming die against the resistance. Make the mold easy.

In a preferred embodiment of the above-mentioned optical element manufacturing apparatus, the preforming section and the main forming section each include a lower heating plate and an L guide serving as a conveyance guide for the molding block on the lower heating plate. There is a configuration in which a character-shaped hook is provided. Parting of the preforming die or the main forming die into the forming material in the forming block becomes a resistance during release, and the tendency of the forming material to be lifted together when lifting the preforming die or the main forming die However, the hook prevents release of the preforming die or the main molding die while preventing the hook from being lifted.

The solution of the molding material of the optical element according to the present invention is as follows.
It is configured such that a substantially convex shape having a convex shape and corresponding to the optical functional surface of the optical element to be arranged in an array is arranged in an array. The main molding is performed through preheating and preforming, but preheating and preforming are performed based on a molding material in which shapes approximating the shape to be finally made in final molding, that is, approximately convex shapes are arranged in an array. Is performed, the occurrence of untransferred portions due to the residual space can be reliably suppressed in all of the optical function surfaces.

In a preferred embodiment of the molding material, the array-like substantially convex shape is formed on a pseudo spherical surface or a pseudo cylinder surface.

The solution of the preforming mold for forming a molding material in the present invention is that a plurality of recesses or through holes are formed on the surface of a flat plate made of a metal member, and an optical glass material is formed on the surface of the recess or through hole. And a platinum release film having low reactivity with the film is formed.

A plurality of recesses or through-holes are provided on the surface of the flat metal member so as to face the optical function surface of the optical element, and a part of the molding material is inserted into the recesses to form a plurality of projections. Is formed, and then the molding material is released from the mold.However, since a release film having low reactivity with the optical glass material is formed on the surface of the concave portion, the release is extremely excellent. Thus, a molding material that does not hinder the main molding can be obtained.

The solution of the lens array optical element in the present invention is obtained by the above-mentioned manufacturing method or the above-mentioned manufacturing apparatus using an optical glass material, one of which is flat and the other is a plurality of spherical or pseudo cylinders. It is shaped into an array of surfaces. By performing pre-heating and pre-forming using a flat molding material, an inexpensive lens array optical element having excellent transferability can be obtained.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method and an apparatus for manufacturing an optical element according to the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1A is a vertical sectional view for explaining the structure of an optical element manufacturing apparatus. In the chamber 1, a preheating section Q1 and a preforming section Q are arranged along the lateral direction.
2, the main forming section Q3, and the cooling section Q4 are arranged in this order. The preheating section Q1 is composed of a lower preheating section and an upper preheating section. The preforming section Q2 is also composed of a lower preforming section and an upper preheating section. The main forming section Q3 is composed of a lower main forming section and an upper main forming section. The cooling unit Q4 includes a lower cooling unit and an upper cooling unit.

A lower cooling plate 3 and a lower heating plate 4 are stacked on a gantry 2 provided in the chamber 1 and fixed on the gantry 2 to constitute a lower preheating unit. The same configurations as those described above are arranged at four places in the horizontal direction in the figure, and a lower preforming portion, a main forming portion, and a cooling portion are configured.

On the other hand, the upper preheating section, the preforming section, the main forming section and the cooling section are provided above the lower side facing the lower section, and are provided on the lower end surface of the shaft 5 suspended from the chamber 1. The upper cooling plate 7 and the upper heating plate 8 are laminated and fixed to the flange 6. However, a preforming die 9 and a main forming die 10 are fixed to the upper heating plate 8 of the preforming portion and the main forming portion, respectively.

The shaft 5 is connected to a pressure mechanism (not shown), for example, an air cylinder or a hydraulic cylinder, and is configured to be movable up and down in the direction of the arrow in the figure.

Also, a molding block 11, which will be described later, is divided into a preliminary heating section Q1, a preliminary molding section Q2, a main molding section Q3, and a cooling section Q4.
The chamber 1 is provided with a rod 12 for sequentially transporting to the chamber 1. Further, the molding block 11 is moved to the chamber 1
Slot 13 for loading and unloading inside and outside
And an outlet 14. A shutter 15 that can be opened and closed is provided at the input port 13 and the take-out port 14. Further, a gas inlet 16 for introducing an inert gas for securing an atmosphere in the chamber 1 for suppressing oxidation of a mold used for molding is provided in the chamber 1.
Is provided.

FIG. 1B is a horizontal sectional view for explaining the conveying means H of the molding apparatus. This figure also describes a method of transporting the molding block 11 described later.

The prepared molding block 11 is first placed on a preparation table 17. The rod 12 sends the cylinder 19 forward in the -Y direction in the figure from the position shown by the broken line, and then moves the cylinder 20 by the distance of the lower heating plate equally arranged in the -X direction by the cylinder 20 so that the upper surface of each lower heating plate 4 Is transported leftward in the figure. At the time of transport, the shutter 15 of the take-out port 14 is lifted in the direction of the arrow + Z shown in FIG. 1 (A) to be opened, and in this state, the molding block 11 is discharged from the chamber 1 and then moved in the -Z direction. To close. Thereafter, the rod 12 moves in the + Y direction and the + X direction, and returns to the original position indicated by the broken line in the figure. The molding block 11 placed on the preparation table 17 is loaded into the chamber 1 by the cylinder 18 via the push rod 21 while the shutter 15 on the loading port 13 side is moved in the + Z direction. Close in the -Z direction.

The transport means H is one which periodically repeats the above-mentioned operation. That is, the molding block 11
Is placed in each of the pre-heating section Q1, the pre-forming section Q2, the main forming section Q3, and the cooling section Q4 for a certain period of time, and then is conveyed using the conveying means H to perform continuous molding. It is.

The transfer means H and the cylinders used for opening and closing the shutters use ordinary air cylinders and the like, and are controlled using an ordinary sequence circuit.

FIGS. 2A and 2B show a molded block 1.
1 is a perspective view and a front view for explaining FIG. FIG.
(A) shows a flat plate-shaped molding material 31 which is one of the components of the molding block, and both surfaces thereof are mirror-finished.

FIG. 2B shows a molding block 11, which is composed of a lower mold 32, a body mold 33, and the above-mentioned molding material 31. The lower mold 32 and the body mold 33 are fitted by a tapered portion 34.

Next, FIGS. 3 (A) and 3 (B) each explain in detail the configuration of the preheating section Q1 and the main forming section Q3.

FIG. 3A shows a state immediately before pressurization in the preforming section Q1. An upper cooling plate 7 and an upper heating plate 8 are stacked on the flange 6 of the shaft 5 and fastened to each other by screws 35. A preforming die 9 is provided on the lower end surface of the upper heating plate 8.
Are fastened with screws 37. Outside the upper heating plate 8,
Stripper pin 38 and compression spring 3 penetrating upper cooling plate 7
9 is provided for releasing the preforming die 9 and the molding material 31 from each other. The lower end of the stripper pin 38 is pressed downward through the body mold 33, and as shown in FIG.
Has an effect of being deformed to a certain extent, biting into the tapered portion 34 provided on the body die 33, and releasing from the preforming die 9.

The structure shown in FIG. 3B shows an initial stage of pressurization of the main molding part Q3.
Indicates a state in which is attached. Using a drive source (not shown), the molding material 31 is configured to generate and pressurize a force F in the figure, and can be moved up and down freely.

Incidentally, the temperature control of the upper and lower cooling plates and the heating plate can be performed by using a usual technique, and a sensor and a control device for the control are provided. Further, the opening and closing of the shutter and the timing of the conveyance are configured to be performed using a sequence control technique.

As described above, the molding apparatus according to the present embodiment constitutes a molding block, is provided with a preheating section capable of heating the entire molding block from above and below, and only the molding block is subjected to the preforming section, the main molding section, A transport means capable of sequentially transporting to the cooling unit is provided, a chamber containing them and a gas inlet for introducing an inert gas into the chamber, and the molding block is put into and out of the chamber,
An opening for taking out and a shutter that can be opened and closed are provided, and the preforming section and the main forming section are provided with a pressing mechanism capable of pressing and deforming the forming material.

(Embodiment 2) A method for manufacturing an optical element according to the present invention will be described with reference to the molding apparatus of Embodiment 1 and FIGS. 1 to 3 and FIGS.

FIG. 2A is a perspective view of a molding material 31 made of a glass material. The molding material 31 is 40 mm × 40
A plate having a size of 3.5 mm × 3.5 mm and both surfaces of which were optically polished was prepared. Glass material is commercially available B2
70-SUPERWITE (transition temperature: 521 ° C, softening temperature: 708 ° C) was used.

FIG. 2B is a front view of the molding block 11. The molding block 11 is made up of a molding material 31 and a lower mold 3.
2 and a body mold 33. Lower mold 32 and body mold 3
3 is fitted by a tapered portion 34. A molding material 31 is placed on a lower mold 32 optically polished on a flat surface. The surface of the lower mold 32 in contact with the molding material 31 is optically polished and further plated with a platinum film having low reactivity with glass. As a constituent material of the lower mold 32 and the body mold 33, tungsten carbide (WC), which is a material having a smaller thermal expansion coefficient than the molding material 31, was employed.

As shown in FIGS. 1A and 1B, the molding block 11 is placed on a preparation table 17. After the forming block 11 in the chamber 1 is transferred by the transfer means H, the preparation table 1
The molding block 11 on 7 was conveyed onto the lower heating plate 4 in the chamber 1 by the push rod 21, and a preliminary heating step of the molding block 11 was performed in the preliminary heating section Q <b> 1. The upper and lower heating plates 4 and 8 are heated at a steady state of 650 ° C. Immediately after the injection of the molding block 11, the temperatures of the upper and lower heating plates temporarily decrease, but gradually recover to the original temperature. In the embodiment, about 2 minutes was set as the standby time until the lower heating plate 4 returned to the temperature. It is desirable that the distance between the upper heating plate 8 and the molding material 31 as the upper surface of the molding block 11 be as close as possible. In this embodiment, the distance is set to 0.5 mm.

Next, by using the above-described conveying means H, the forming block 11 is preheated to the preheating section Q which is constantly set at 720 ° C.
After being transported to 1, using a drive source and a pressure mechanism (not shown), the shaft 5 is lowered to bring the preforming die 9 into contact with the forming material 31, and heating is continued for 1 minute in the contact state. A pressing force of 12000 N (Newton) was applied to the molding material 31 and held for 1 minute. This is the preforming step.

FIGS. 4A and 4B show the preform 9 and the preform 4 attached to the upper heating plate 8 of the preform Q2.
5 is described in detail.

The preforming die 9 of the present embodiment shown in FIG.
In the flat plate-shaped surface made of a stainless steel member, a concave portion 41 having the same arrangement pitch as the lens array to be obtained is carved, and a mounting hole 42 for the upper heating plate 8 is provided. ing. About the concave part 41, the thing with a 1.2 mm engraving depth was machined using a ball end mill having a radius of curvature of R4 and a machining center in 80 places.
After polishing the surface to a mirror surface, a platinum film was plated on the mirror surface.

FIG. 4B shows a preformed product 45 obtained after pressing deformation in the preformed portion Q2. This preform 45
On the flat plate-like surface, a convex portion 43 having a shape substantially opposite to the concave portion 41 of the preforming die 9 was faithfully formed. Preform 4
Numeral 5 is the one that is conveyed to the main forming section Q3 in the actual manufacturing process and further formed by the main forming die 10 having a shape opposite to the lens array shape to be obtained.

FIG. 5A shows another embodiment of the preforming die 9. In this preforming die 9, a plurality of straight grooves 46 are carved, and mounting holes 47 are formed. The shape of the concave portion is different from that in FIG. 4A, and the lens array is equally divided (eight divisions).
A plurality of grooves were formed. Polishing of the processed surface and formation of a platinum film employ the same method as that shown in FIG.

FIG. 5B shows a preformed product 49 obtained by using the preforming die 9 at the same temperature setting, time setting and pressing force setting as described above. This preform 4
In No. 9, a convex portion (protrusion) 48 having a shape substantially opposite to the straight groove 46 of the preforming die 9 was faithfully formed.

The preforms 9 in FIGS. 4 and 5 are all engraved with a bottom.
If the convex shapes of the arrayed convex portions 43 and 48 can be formed in
The through-hole or through-hole may be processed, and the bite into the mold is slightly large, but if the chamfering of the through-hole and the amount of pressing deformation are controlled, it is confirmed that almost the same preform is obtained. I have.

The preforms 45 and 49 obtained in the description of FIG. 4B and FIG.
In the main molding step performed in the above, there is no formation of a residual space between the molding die and the molding material as described in the conventional example, so that there is no untransferred portion, and it works so that precise transfer can be performed. .

It is needless to say that the preforms 45 and 49 can also be used as molding materials in the molding described in the conventional example.

FIG. 6 is a perspective view of the main forming die 51 provided for explaining the main forming step. The main mold 51 has a lens array 52 in which concave lens surfaces 52 are arranged at 80 positions. The lens surface 52 has a radius of curvature R of 13.5 mm and is carved by 0.2 mm. 53 is a mounting hole. Tungsten carbide is used as a constituent material of the main mold 51, and the surface of the lens surface 52 is precision-polished to an optical mirror surface and then a platinum film is applied by plating. Immediately after the upper and lower heating plates 8 and 4 are conveyed to the main molding step set at 720 ° C., the molding block 11 presses with a pressing force of 10,000 N,
After the pressurization is continued for 2 minutes and the pressurization is released, the forming block 11 is transported to the cooling section Q4 having the same configuration as the preheating section Q1, and the upper and lower heating plates 8, 4 are kept at 500 ° C. The set cooling step was performed for 2 minutes.

Thereafter, the molding block 11 is
Out of the outlet 14 and let it cool down enough
The molding block 11 was disassembled.

FIG. 7 shows a lens array-shaped optical element 5 obtained as a result of performing the above-mentioned preheating step, preforming step, main forming step and cooling step with a cycle time of 2 minutes.
4 shows a perspective view of FIG. In the optical element 54, the convex optical surfaces 55 were arranged and arranged, so that the transfer could be faithfully and precisely performed on all the opposite shapes of the lens surface 52 of the main mold 51.

When the shape accuracy of the optical surface was measured three-dimensionally, only the shrinkage of the molding material had a deviation from the desired shape. The plane accuracy opposite to that of the optical surface was measured with a Fizeau optical interferometer.
A flatness of 33 nm) or less was obtained, and it was confirmed that a lens array optical element capable of being practically used could be manufactured.

(Embodiment 3) FIG. 8 shows another mold releasing means M for a preforming die, a main die and a molding material. An L-shaped hook 56 is fixed to a side surface of the lower heating plate 4 with a screw 57. The hook 56 is attached in the conveying direction of the forming block 11 and also serves as a guide when the forming block 11 is transferred. When the upper preforming portion and the main forming portion are lifted upward, the trunk die 33 is restricted by the hook 56 and does not lift upward. Also, since the molding material 31 is deformed and enters the tapered portion 34 of the body mold 33,
Acts on mold release from the mold.

When an optical element was molded under the same conditions as in the second embodiment, an optical element 54 shown in FIG. 7 was obtained. Evaluation of the shape accuracy using a three-dimensional measuring device and the flatness using an optical interferometer confirmed that a device having almost the same accuracy as the optical element obtained in the second embodiment was obtained.

[0064]

According to the present invention, only the forming block composed of the lower mold, the body mold, and the flat forming material is sequentially subjected to the steps of a pre-heating section, a pre-forming section, a main forming section, and a cooling section to form a flat plate. Even if a molding material is used, an optical element of a lens array in which an untransferred portion due to a residual space does not remain can be manufactured at low cost. Further, the number of expensive molds having an optical lens surface formed thereon can be reduced, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view and a horizontal sectional view illustrating an optical element manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view and a front view illustrating a molded block according to each embodiment of the present invention.

FIG. 3 is a front view showing details of the optical device manufacturing apparatus according to the first embodiment of the present invention;

FIG. 4 is a perspective view showing a preforming die and a preformed product used in the embodiment of the present invention.

FIG. 5 is a perspective view showing another form of a preform and a preform used in the embodiment of the present invention.

FIG. 6 is a perspective view of a main mold according to a second embodiment of the present invention.

FIG. 7 is a perspective view of a lens array-shaped optical element obtained in the embodiment of the present invention.

FIG. 8 is a front view showing an optical element manufacturing apparatus according to a third embodiment of the present invention.

FIG. 9 is a front view for explaining a molding method in a conventional technique.

FIG. 10 is a diagram illustrating the principle of a liquid crystal projector using a lens array optical element.

[Explanation of symbols]

 Q1 Preheating section Q2 Preforming section Q3 Main forming section Q4 Cooling section H Conveying means M Demolding means 1 Chamber 2 Stand 3 Lower cooling plate 4 Lower heating plate 5 Shaft 6 Flange 7 Upper cooling plate 8 Upper heating plate 9 Preforming die REFERENCE SIGNS LIST 10 molding die 11 molding block 12 rod 13 inlet 14 outlet 15 shutter 16 gas inlet 17 preparation table 18, 19, 20 cylinder 21 push rod 31 molding material 32 lower mold 33 trunk mold 34 taper 35, 37 fixing screw Reference Signs List 38 stripper pin 39 compression spring 41 concave part 42, 47, 53 mounting hole 43 convex part 45, 49 preformed product 46 straight groove 48 convex part 51 main molding die 52 lens surface 54 optical element 55 optical surface 56 hook

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) G02B 3/00 G02B 3/00 A (72) Inventor Takahisa Kondo 1006 Kazuma, Kazuma, Kazuma, Osaka Matsushita Electric Industrial (72) Inventor Masaaki Sunohara 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 4G015 HA01

Claims (9)

[Claims] 1. A pre-heating device for pre-heating an entire molding block including a lower mold, a body mold fitted to the lower mold, and a molding material guided by the body mold and placed on the lower mold. A heating step; a preforming step of pressing and deforming the forming material softened by the preheating with a preforming mold to obtain a preformed article; and the preforming article by a main forming die having an optical function surface configured in an array. And a cooling step of cooling the entire molding block, and sequentially transporting the molding block to at least the respective steps of the preheating, preforming, main molding and cooling. A method for producing an optical element, comprising: 2. A pre-heating unit which can pre-heat an entire molding block composed of a lower die, a body die, and a molding material placed on the lower die, which are fitted to each other with a taper; A preforming part capable of heating and pressing the molding material of the molding block; and a main molding die having an upwardly concave optical function surface formed in an array, and heating and pressing the molding material of the molding block. A possible main molding section, a cooling section for cooling the entire molding block, a chamber containing the four sections, and a preheating section, a preforming section, a main molding section and a cooling section for the molding block. Transport means for sequentially transporting the molding block into and out of the chamber; an inlet and an outlet having a shutter for loading and unloading the molding block into and out of the chamber; and a gas guide for feeding an inert gas into the chamber. Apparatus for producing an optical element characterized in that it comprises a mouth. 3. The preforming section and the main forming section each include an upper heating plate, and a side surface of the upper heating plate for assisting release of the preforming die or the main molding die from the forming block. The apparatus for manufacturing an optical element according to claim 2, further comprising a stripper pin. 4. The preforming section and the main forming section each include a lower heating plate, and an L-shaped hook serving also as a conveyance guide of the molding block on the lower heating plate. The optical device manufacturing apparatus according to claim 2 or 3, wherein: 5. A flat plate made of a glass material is provided on one or both sides thereof with a convex shape and a substantially convex shape corresponding to an optical functional surface of an optical element to be arranged in an array. A molding material for an optical element, comprising: 6. The molding material for an optical element according to claim 5, wherein the array-like substantially convex shape is formed on a pseudo spherical surface or a pseudo cylinder surface. 7. A plurality of recesses or through-holes are formed on the surface of a flat plate made of a metal member, and a platinum release film having low reactivity with an optical glass material is formed on the surface of the recesses or through-holes. A preforming mold for producing a molding material, characterized in that: 8. An optical glass material obtained by the manufacturing method according to claim 1, wherein one is formed into a flat surface and the other is formed into an array of a plurality of spherical surfaces or pseudo cylinder surfaces. Lens array optical element. 9. An optical glass material obtained by the manufacturing apparatus according to claim 2, wherein one is formed into a flat surface and the other is formed into an array of a plurality of spherical surfaces or pseudo cylinder surfaces. Lens array optical element.