JP2004107172A - Method of forming optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of forming an optical element provided with an excellent optical functional surface free from recessed part due to residual air in a cavity. <P>SOLUTION: The method of forming the optical device is composed of a process for preparing a nearly barrel type optical base material 10 provided with two plane surfaces 10a formed by holding a nearly spherical lumpy optical base material 10' between an upper die 12 for base material and a lower die 13 for base material and press forming to transfer a plane upper die face 12a or a plane lower die surface 13a and a side surface 10b having a bulged center part, a process for press forming the nearly barrel type optical base material 10 by setting in a cavity of an optical device forming die provided with a drum die 1, an upper die 2 and a lower die 3, arranging so that the side surface 10b of the optical base material faces an upper die transfer surface 2a and a lower die transfer surface 3a, holding the optical base material 10 between the upper die 2 and the lower die 3 and heating and pressing and a process for obtaining the optical element 20 provided with the optical functional surface 20a by decreasing the temperature of the inside of the cavity to cool the optical base material 10. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for molding an optical element (or glass molded product) by sandwiching an optical material (or glass material) between an upper mold and a lower mold and applying heat and pressure.
[0002]
[Prior art]
In recent years, an optical material (or glass material) is arranged in a cavity of an optical element molding die having a body mold, an upper mold, and a lower mold, and the optical material (or glass material) is sandwiched between the upper mold and the lower mold. The press-forming method, in which an optical element (or a glass molded product) is formed by pressurizing while heating at, has come to be performed.
[0003]
Then, for example, when the slit type optical element 20 having the optical function surface 20A as shown in FIG. 5 is formed, according to the related art, a columnar optical material (or glass material) 100 as shown in FIG. After being set in the cavity of the optical element molding die having the body die 1, the upper die 2 and the lower die 3, the upper die 2 and the lower die 3 are used to form a cylindrical optical material (or glass material) 100. , And press-molding by applying pressure while heating, the transfer surfaces of the upper mold 2 and the lower mold 3 are transferred to the side surface 100b of the optical material (or glass material), and the slit-type optical element having the optical function surface 20A is provided. 20 (or a glass molded product) (see FIG. 7).
[0004]
According to the related art, a plate-shaped material such as a glass plate is cut into a disk shape by cutting, and as shown in FIG. 6, a columnar glass plate surface 100a cut into a circular shape and a side surface 100b thereof. An optical material 100 is prepared, the optical material 100 is set in a cavity of an optical element molding die, and press-molded to transfer the transfer surfaces of the upper mold 2 and the lower mold 3 to the side surface 100b, thereby obtaining an optical material. The slit type lens 20 having the functional surface 20A was molded.
[0005]
FIG. 7 shows an example of an optical element molding die for molding the slit type optical element 20 shown in FIG. 5, and FIG. 7 (a) shows a cylindrical optical material (or glass material) 100. FIG. 7B is a cross-sectional view of the optical material (or glass material) when viewed from the surface 100a of the plate-like glass plate when set in the cavity of the mold for molding an optical element. It is sectional drawing when a raw material (or glass material) is seen from the side surface 100b side.
Reference numeral 1A in the figure denotes an air passage formed in the body mold 1 for guiding the upper mold 2 and the lower mold 3 and for discharging air in the cavity.
[0006]
[Problems to be solved by the invention]
As in the prior art, when a columnar optical material produced by cutting out a plate-like glass material is used, the optical material 100 is set in the cavity of the optical element molding die, and the upper die 2 or the lower die 3 When the transfer surface and the side surface 100b of the optical material are opposed to each other, as shown in FIG. 7A, in the circumferential direction of the side surface 100b, the center of the transfer surface of the upper mold 2 or the lower mold 3 and the optical element. Although the material 100 fits and no sealed space is generated between the transfer surface and the optical material, as shown in FIG. 7B, in the longitudinal direction of the side surface 100b (the thickness direction of the glass plate), A sealed space is generated between the central portion of the transfer surface and the optical material 100, and it is difficult to remove air in the sealed space.
[0007]
FIG. 8 is a diagram for explaining a method of molding an optical element according to the related art.
FIG. 8A is a partially enlarged view of FIG. 7B, and is a cross-sectional view of the optical material (or glass material) 100 set in the optical element molding die as viewed from the side surface 100b side.
As shown in FIG. 8A, a columnar optical material (or glass material) 100 produced by cutting out a glass plate or the like is set in a cavity of an optical element molding die, and a side surface 100b of the optical material is When the transfer surface is arranged so as to face the upper transfer surface 2A or the lower transfer surface 3A, if the curvature of the transfer surface is large (the concave R is sharp), a closed space is formed between the central portion of the transfer surface and the optical material 100. When the optical material (or glass material) 100 is pressurized while being heated while being heated, as shown in FIG. 8B, the optical material (or glass material) 100 and the upper mold transfer surface A (or lower mold transfer surface A) are formed. A recess 101 is formed in the optical material (or glass material) 100 due to the air remaining between the mold transfer surface 3A) and the surface accuracy of the optical function surface of the formed slit optical element 20 is reduced. Not had.
[0008]
In other words, when molding an optical material having a large curvature of the optical function surface such as a slit-type optical element, for example, a columnar optical material (or glass material) 100 formed by cutting out a glass plate and forming it as in the related art was used. In this case, since the longitudinal direction of the side surface 100b is flat, when the optical element (or glass molded product) is formed using a transfer surface having a large curvature (a transfer surface with a concave R being tight), the transfer surface and the optical material are formed. And a closed space was created between them.
When air in the cavity is removed from the air passage 1A at the time of press molding, air in the closed space tends to remain, and this air causes a problem in shape transfer performance such as formation of a dent 101. The quality of the optical element (or glass molded product) is deteriorated, for example, the surface accuracy of the optical functional surface 20A of the molded optical element (or glass molded product) 20 is reduced.
Although a method for preventing air from remaining between an optical material (or a glass material) and a transfer surface is also known (see Patent Documents 1 and 2), in the case of Patent Document 1, a groove is formed in the optical material. It is necessary to perform such processing as described above, which increases the processing cost. In the case of Patent Document 2, a special pressurization control is required, and the operation is complicated.
In addition, it is conceivable that the side surface 100b of the cylindrical optical material (or the glass material) produced by cutting out a glass plate or the like is subjected to a curved surface polishing process and the side surface 100b is rounded, but also in this case, the processing cost is increased. I will.
[0009]
Therefore, the present invention prevents a closed space from being generated between the optical material (or glass material) and the transfer surface, provides a good optical function surface without dents or the like due to residual air in the cavity, and provides a low cost. It is an object of the present invention to provide a method for molding an optical element which can be manufactured at a high speed.
[0010]
[Patent Document 1]
JP-A-5-163026 (page 3, FIG. 2)
[Patent Document 2]
JP-A-7-315855 (pages 3-6)
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a method for molding an optical element according to the present invention includes the steps of: preparing a substantially spherical massive optical material having the same volume as the volume of an optical element to be obtained; A substantially barrel-shaped optic having two flat surfaces formed by pressing and pressing between a mold and a lower mold for a material, and transferring a flat upper mold surface or a lower mold surface, and a center portion bulging side surface. A step of preparing a material, setting the substantially barrel-shaped optical material in a cavity of an optical element molding die having a barrel die, an upper die, and a lower die, and setting a side surface of the optical material to an upper die transfer surface; And after being arranged so as to face the lower mold transfer surface, the optical material is sandwiched between an upper mold and a lower mold, press-molded by applying pressure in a heated state, and cooling the optical material by lowering the temperature in the cavity. And obtaining an optical element having an optical function surface That.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 illustrates a manufacturing process of an optical material (or glass material) 10 according to an embodiment of the present invention.
In this embodiment, when producing the optical material (or glass material) 10, first, a molten optical material (or molten glass material) heated and melted is dropped from a nozzle 11 having a predetermined shape and diameter. A substantially spherical massive optical material (or massive glass material) 10 'is produced (see FIG. 1A). The dropped molten optical material (or molten glass material) is cooled while falling in the air and becomes substantially spherical.
[0014]
At this time, the temperature and viscosity of the molten optical material (or the molten glass material), the shape and diameter of the nozzle 11, the method of extrusion from the nozzle 11, and the like are appropriately set, and the amount of the dropped optical material is adjusted by adjusting the dropping amount. The volume of the raw material (or bulk glass material) 10 ′ can be adjusted to a desired volume, and the drop amount can be equalized with high accuracy, and a plurality of bulk optical elements (or bulk glass material) 10 ′ are produced. In this case, high volume accuracy can be maintained.
[0015]
Then, after forming a substantially spherical massive optical material (or massive glass material) 10 'having the same volume as the optical element (or glass molded product) 20 to be acquired, as shown in FIG. The above-mentioned substantially spherical massive optical material (or massive glass material) 10 ′ is sandwiched between a material upper mold 12 and a material lower mold 13 and pressed to form a flat upper mold surface 12 a and lower mold surface 13 a. By the transfer, an optical material (or glass material) 10 having two flat surfaces 10a and a side surface 10b whose central portion is swollen is produced.
That is, a substantially barrel-shaped optical material (or glass material) 10 ′ is obtained by crushing a substantially spherical massive optical material (or massive glass material) 10 ′ from above and below with a plane, so that the central portion of the cylindrical body expands. It is manufactured (see FIG. 1C).
[0016]
As shown in FIG. 1 (b), after a plurality of substantially spherical massive optical materials (or massive glass materials) 10 ′ are arranged between a material upper mold 12 and a material lower mold 13, The material (or lump glass material) is heated and softened, and then the upper mold for material 12 is lowered to compress the lump optical material (or lump glass material) 10 ′, thereby obtaining a substantially barrel-shaped optical material ( (Or glass material) 10 can be produced at a time.
[0017]
Also, compared to the optical material 100 produced by cutting as in the prior art, higher volume accuracy can be maintained, and after the cutting, the side surface 100b of the columnar optical material is curved and the side surface is rounded. The optical material (or glass material) 10 can be produced more easily and cheaply.
[0018]
In this embodiment, after heating and softening a lump optical material (or lump glass material) 10 ′ using an upper mold for material 12 and a lower mold for material 13, it is gradually cooled, and then gradually cooled. The mold 12 is raised to obtain a substantially barrel-shaped optical material (or glass material) 10.
[0019]
Subsequently, the substantially barrel-shaped optical material (or glass material) 10 produced as described above is set in the cavity of the optical element molding die, and the optical element (or glass molded product) is molded.
[0020]
2 and 3 illustrate a process of forming an optical element (or glass molded product) 20 according to an embodiment of the present invention.
The optical element molding die shown in FIGS. 2 and 3 is an optical element molding die for molding the slit optical element 20 shown in FIG. 5, and FIG. FIG. 2 is a cross-sectional view of the optical material (or glass material) 10 viewed from the plane 10a side, and FIG. 2 shows the optical material (or glass material) 10 set in the cavity of the optical element molding die from the side surface 10b side. It is sectional drawing at the time of seeing.
Reference numeral 1A in the figure denotes an air passage formed in the body mold 1 for guiding the upper mold 2 and the lower mold 3 and for discharging air in the cavity.
[0021]
In this embodiment, the substantially barrel-shaped optical material 10 (or glass material) is set in a cavity of an optical element molding die having a body die 1, an upper die 2, and a lower die 3, and the optical material is set. (Or a glass material) 10 is sandwiched between the upper mold 2 and the lower mold 3, and pressurized while heating to form a slit-type optical element 20 as shown in FIG. 5.
[0022]
In setting the optical material 10 in the cavity of the optical element molding die, as shown in FIGS. 2A and 3A, the side surface 10b of the substantially barrel-shaped optical material 10 is moved to the upper mold transfer surface 2a and the upper mold transfer surface 2a. After being arranged so as to face the lower mold transfer surface 3a, the optical material is sandwiched between the upper mold 2 and the lower mold 3 as shown in FIGS. While softening 10, the upper mold 2 is lowered and pressurized to perform press molding.
[0023]
FIG. 4 is a partially enlarged view of FIG. 3, and is a cross-sectional view of the optical material (or glass material) 10 set in the optical element molding die as viewed from the side surface 10b side.
As shown in FIG. 4A which is a partially enlarged view of FIG. 3A, a substantially barrel-shaped optical material (or glass material) 10 is set in a cavity of an optical element molding die. When the side surface 10b whose central portion is expanded is opposed to the upper mold transfer surface 2A and the lower mold transfer surface 3A, the center portion of the side surface 10b and the transfer surface fit, and both ends of the side surface 10b are open. Therefore, it is possible to prevent the generation of a closed space between the transfer surface and the optical material 10.
[0024]
Then, as shown in FIG. 4B, which is a partially enlarged view of FIG. 3B, the upper mold 2 is lowered and pressurized while heating the optical material 10 set in the cavity. Since there is no closed space between the material 10 and the air, the air between the transfer surface and the optical material 10 can be easily removed, and the air in the cavity can be easily discharged from the air passage 1A. That is, unlike the molding method of the optical element according to the prior art, there is no fear that the air element forms the dent 101 due to the residual air, the transfer performance by the transfer surface is improved, and the optical element having the optical function surface 20A with high surface accuracy is provided. 20 can be molded.
[0025]
In addition, for example, by disposing an optical element molding die in a chamber (not shown) and increasing the vacuum characteristics in the chamber, the air in the cavity during press molding is reduced by the body mold 1. The air is discharged from the cavity while being sucked from the air passage 1A formed in the cavity, and the air in the cavity is easily removed.
[0026]
Also, the curvature of the central portion on the side surface 10b of the substantially barrel-shaped optical material is set to the upper mold transfer surface 2a or the lower mold transfer mold of the optical element molding die so as not to form a closed space between the transfer surface and the optical material. It is preferable to manufacture the optical material 10 so as to be larger than the curvature of the surface 3a (see FIG. 4A).
[0027]
Furthermore, when the substantially barrel-shaped optical material 10 is set in the cavity of the optical element molding die, and the side face 10b whose central portion is expanded is placed on the lower mold 3, the optical material 10 is inclined by 10 ° or more. It is preferable to adjust the material thickness of the optical material 10 so that it does not occur (see FIG. 4A).
In the optical material 10 according to the present invention, since the central portion of the side surface 10b is bulged, the central portion of the side surface 10b is grounded to the lower mold transfer surface 3a, and the arrangement becomes unstable. Therefore, for example, when the optical material 10 having a small material thickness of the optical material 10 is set in the cavity of the optical element molding die, the optical material 10 is largely tilted in the cavity, which adversely affects the molding of the optical element. By adjusting the material thickness of the optical material 10, a large inclination of the optical material 10 in the cavity surrounded by the inner peripheral surface of the barrel mold 1 can be suppressed. It can be adjusted so that it does not tilt more than 10 °.
[0028]
The curvature of the side surface 10b of the optical material and the adjustment of the material thickness of the optical material 10 are adjusted when the substantially spherical massive optical material 10 'is sandwiched between the material upper mold 12 and the material lower mold 13 and pressed. It can be easily adjusted by adjusting the force (for example, the degree of lowering the material upper die) of pressing the bulk optical material 10 ′ from above and below.
[0029]
That is, as in this embodiment, a substantially barrel-shaped optical material (or glass material) 10 produced by press-molding a substantially barrel-shaped optical material by substantially spherical bulk optical pressure molding is used as an optical element molding die. When the optical material 10 is set in the cavity and the side surface 10b of the optical material is arranged so as to face the upper mold transfer surface 2a and the lower mold transfer surface 3a, as shown in FIG. In the circumferential direction, the center of the transfer surface of the upper mold 2 or the lower mold 3 fits with the optical material 10, and as shown in FIG. 2A, the longitudinal direction of the optical material side surface 10b (optical material In the thickness direction of the upper mold 2 or the lower mold 3, the central portion of the transfer surface of the upper mold 2 or the lower mold 3 fits with the optical material 10, thereby preventing the occurrence of a closed space between the transfer surface and the optical material 10. it can.
[0030]
In this embodiment, the substantially barrel-shaped optical material (or glass material) 10 softened by heating is press-molded by the upper mold 2 and the lower mold 3, and then gradually cooled, and thereafter, The upper mold 12 was raised to obtain an optical element (or glass molded product) 20 having an optical functional surface 20A having high surface accuracy.
[0031]
【The invention's effect】
As described above, according to the present invention, after producing a substantially spherical bulk optical material having the same volume as the volume of the optical element to be obtained, the bulk optical material is formed into a material upper mold and a material lower mold. Forming a substantially barrel-shaped optical material having two flat surfaces formed by transferring a flat upper mold surface or a lower mold surface, and a central portion bulging; Setting the substantially barrel-shaped optical material in a cavity of an optical element molding die having a body die, an upper die, and a lower die, and setting the side surfaces of the optical material to an upper die transfer surface and a lower die transfer surface. After being arranged so as to face each other, the optical material is sandwiched between an upper mold and a lower mold, and a step of press-molding by pressurizing in a heated state, cooling the optical material by lowering the temperature in the cavity, and cooling the optical functional surface. Forming the optical element from the step of obtaining the provided optical element.
Thereby, for example, even when a slit type optical element having a large curvature of the optical function surface is formed (when an upper mold or a lower mold having a transfer surface with a large curvature is used), the transfer surface and the optical material (or glass material) are used. ) Does not form a closed space, and air in the cavity can be easily removed. Since there is no possibility that the transfer surface is adversely affected by the residual air, an optical element having a high shape transfer performance when transferring the transfer surface to an optical material (or a glass material) and having an optical functional surface with high surface accuracy is obtained. be able to.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a method for producing an optical material according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view of an optical material set in a cavity of an optical element molding die when viewed from a plane side.
FIG. 3 is a cross-sectional view of an optical material set in a cavity of an optical element molding die when viewed from a side.
FIG. 4 is a partially enlarged view of FIG. 3;
FIG. 5 is a perspective view of an optical element.
FIG. 6 is a perspective view of an optical material according to the related art.
FIG. 7 is a sectional view of an optical material set in a cavity of an optical element molding die.
FIG. 8 is a diagram illustrating a method for molding an optical material according to a conventional technique.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Drum 2 Upper mold 2a Upper mold transfer surface 3 Lower mold 3a Lower mold transfer surface 10 'Block optical material (or block glass material)
10 Optical material (or glass material)
10a flat surface 10b side surface 20 optical material (or glass material)

Claims (4)

After producing a substantially spherical massive optical material (10 ') having the same volume as the volume of the optical element to be acquired, the massive optical material (10') is divided into an upper mold for material (12) and a lower mold for material ( 13) and press-molded.
A substantially barrel-shaped optical material (2) having two flat surfaces (10a) formed by transferring the flat upper mold surface (12a) or lower mold surface (13a) and a side surface (10b) whose central portion is bulged. 10) a step of producing;
The substantially barrel-shaped optical material (10) is set in a cavity of an optical element molding die having a body die (1), an upper die (2) and a lower die (3), and a side surface of the optical material. After arranging (10b) so as to face the upper mold transfer surface (2a) and the lower mold transfer surface (3a), the optical material (10) is sandwiched between the upper mold (2) and the lower mold (3), A step of press-forming by applying pressure in a heated state;
Cooling the optical material (10) by lowering the temperature in the cavity to obtain an optical element (20) having an optically functional surface (20a). The curvature of the center part of the side surface (10b) of the substantially barrel-shaped optical material is larger than the curvature of the upper die transfer surface (2a) or the lower die transfer surface (3a) of the optical element molding die. 2. The method for molding an optical element according to 1. While adjusting the pressing force, the substantially spherical block-shaped optical material (10 ') is sandwiched between the upper mold for material (12) and the lower mold for material (13) and press-molded to adjust the material thickness. While producing the optical material (10),
The optical material (10) is set in a cavity of an optical element molding die, and when the optical material (10) is placed on the lower mold (3), the optical material (10) is not inclined by more than 10 °. The method for molding an optical element according to claim 1. The molten optical material which has been heated to a molten state is dropped from a nozzle (11) to produce a substantially spherical massive optical material (10 '). Optical element molding method.

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