JP3199461B2 - Optical element molding method and molding die - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding method for press-molding an optical element and a mold for press molding.

[0002]

2. Description of the Related Art Hitherto, as examples of this type of lens molding method and molding die, the inventions disclosed in JP-A-2-149436 and JP-A-3-45521 are known.

[0003] The invention described in the former publication is a mold for forming a multi-cavity concave lens, and one surface is made flat by pressing a heat-softened sheet glass material between upper and lower molds. A plurality of concave lenses whose other surfaces form a concave curved surface are simultaneously formed.

[0004] The molding die has a plurality of flat surfaces formed at the tip end and a plurality of flat surfaces formed at the other end, facing the flat molding surface formed on the lower die. An upper mold equipped with a cylindrical mold is provided.

[0005] Since the ends forming the plane of the cylindrical mold are in contact with the plane of the upper mold, the plurality of molds move integrally with the upper mold in the pressing direction, and the moving distance. Is limited by the distance between the parallel surfaces of the cylindrical body mold provided between the upper and lower molds so that the desired minimum thickness of the concave lens is determined.

In the molding die, since a curved surface for forming a lens is formed on the molding surface of each cylindrical mold attached to the upper die, various concave lenses having different curved surface shapes are used. By manufacturing in advance a cylindrical mold having curved surfaces corresponding to the curved surfaces of various concave lenses to be molded, the mold can be selected from the molds and used, so that versatility can be improved. Further, it is easy to manufacture a molding die.

The invention described in the latter publication is a method for simultaneously molding a plurality of lenses using a pair of upper and lower molds, and the upper and lower molds are provided with a lens molding surface on each of both opposing molding surfaces. Are mounted. A lattice-shaped glass material holder is provided between the upper and lower molds at a position corresponding to each of the plurality of molds, and a hole having a diameter corresponding to the finished surface of the mold.

At the time of pressing the lenses, the heat-softened sheet glass material is placed on the lattice-shaped glass material holder, and the upper mold is lowered to simultaneously form a plurality of lenses.

In this case, since the glass material which has been heated and softened is placed on a lattice-shaped glass material holder and molded, the molding can be performed without much consideration of the area, weight, thickness and temperature of the glass material, and the lens is taken out. There is little distortion of the lens.

Also, conventionally, when adjusting the distance between the upper and lower dies when the optical element is pressed and molded by a pair of upper and lower molding dies, the upper and lower dies are brought close to each other, and the telescope is provided from outside the molding dies. By directly measuring the distance between the apex of the upper mold forming surface and the apex of the lower mold forming surface, the distance between the upper mold and the lower mold (thickness of the optical element) is adjusted or molded. 2. Description of the Related Art The thickness of a lens is measured, and the numerical value is fed back to adjust the mold interval. This method is widely used because the apparatus is simple and high accuracy can be easily obtained.

[0011]

However, according to the conventional method for adjusting the distance between a pair of upper and lower molds, the shape of the upper and lower mold surfaces is convex or flat, and the optical function surface optical axes are aligned with each other. If so, you can set the mold spacing by directly measuring the top of the mold on the optical axis, or if you want to measure the top of the pressed lens For example, the thickness measurement can be performed regardless of the shape of the lens.

However, like the optical element 20 shown in FIGS. 16 to 18 (FIG. 16 is a plan view of the optical element, FIG. 17 is a side view thereof, and FIG. When the optical axis 20d of the upper optical function surface 20c is inclined with respect to the optical axis 20b, when setting the interval between a pair of upper and lower molding dies for molding the optical element 20, the molding on the inclined side is performed. It is difficult to accurately recognize the vertex of the surface even when trying to view it with a telescope. Even if the distance between the vertices of the surface is measured by such a method, high mold-to-mold accuracy (thickness of the optical element) is obtained. I couldn't do that.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and an optical element in which the optical axis of one optical function surface is inclined with respect to the optical axis of the other optical function surface,
With a simple device, high-precision wall thickness can be easily obtained.
An object of the present invention is to provide an optical element molding method and a molding die.

[0014]

In order to achieve the above object, the present invention provides a method for forming an optical element by press-forming a softened optical element material with a pair of molding dies.
By setting the plane portions provided on portions other than the optical function surface portion of the molding surfaces of the pair of molding dies as reference surfaces, by measuring the distance between the reference surfaces, the distance between the pair of molding dies is measured. Is measured, and the optical element material is press-molded by the pair of molding dies. Further, the present invention provides a method for molding an optical element, in which a heat-softened glass material is press-molded with a pair of molding dies, wherein the glass material is provided on a portion other than the optical function surface portion of the molding surface of the molding die of the optical element. With the flat surface portion as a reference surface, the interval between the molding dies is set while measuring the interval between the reference surfaces of both molding dies, and thereafter, the glass material is supplied between the pair of molding dies. And press forming.

Further, the mold for molding the optical element of the present invention is
Forming a molding surface of a plurality of optical function surfaces on a molding surface of an optical element molding die composed of a single member, and providing a reference surface having a flat surface formed on a molding surface other than the plurality of optical function surfaces. It is a feature.

[0016]

According to the method for molding an optical element and the mold for molding of the present invention, a plane portion is provided on the molding surface of the mold other than the optical function surface portion. By using it as a reference plane, it is possible to determine the mold interval with high accuracy while measuring the mold interval.

Also, when measuring the thickness of the molded optical element, a pair of planes is transferred to the optical element by the plane part of the mold. Thickness can be measured with high accuracy. Further, for example, even in the case of obtaining a plurality of optical elements by one press molding, by measuring one location of a molded article including a plurality of optical elements, the thickness of the plurality of optical elements can be simultaneously determined. And it can be easily confirmed.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

[0019]

Embodiment 1 FIGS. 1 to 7 show Embodiment 1 of the present invention. 6 and 7 (FIG. 6 is a plan view of an optical element,
FIG. 7 is a columnar shape as shown in FIG.
The optical element 6 having the lower optical function surface 6c in which the upper optical function surface 6a is flat and the optical axis 6d of the lower optical function surface 6c is inclined with respect to the optical axis 6b of the upper optical function surface 6a. A method of press molding and an apparatus therefor will be described.

As shown in FIG. 1, a mold for press-molding the optical element 6 is provided with a horizontal optical function surface portion 6a1 on a molding surface 1a of the upper mold 1, and a molding surface 2a of the lower mold 2 as shown in FIG. As shown in FIG. 3 (FIG. 2 is a plan view of the lower die, and FIG. 3 is a sectional view taken along the line AA), two inclined circular optical function surface portions 6c1 are arranged equiangularly with respect to the optical axis. A flat portion 2b1 is provided on a portion other than the two optical function surface portions 6c1 to connect the surface top portions 2c to each other.

In press-molding using the upper and lower dies 1 and 2, first, the optical function surface portion (reference surface) 6a1 of the molding surface 1a of the upper die 1 and the flat portion (reference surface) of the molding surface 2a of the lower die 2 are formed. )
2b1 is attached to a molding device (not shown) so as to be parallel.

Then, the upper and lower dies 1, 2 are provided from outside the molding apparatus.
A telescope equipped with a scale for measurement is installed at a position where the distance between the telescopes can be measured, and the optical axis of the telescope and the scale provided in the telescope are aligned with the reference planes of the upper and lower dies 1 and 2 (planes). Part) The position is adjusted so as to be parallel to 6a1 and 6b1.

At the time of measurement with the telescope, the distance between the reference planes (flat portions) 6a1 and 6b1 of the upper and lower dies 1 and 2 is read by operating the scale in the telescope up and down, and the numerical values of this measurement are used to read the upper and lower dies 1 and 2. Is adjusted so that a desired mold spacing (thickness of the optical element) is obtained.

After the mold interval is set, the mold is opened, and the glass material as the optical element material placed on the transport member 3 is removed.
4A and 4B, two optical elements 6 shown in FIG. 6 are included by being conveyed between the upper and lower dies 1 and 2 by the transfer arm 5 and press-molded by the upper and lower dies 1 and 2 to the above set mold interval. A molded product 7 shown in FIG. 5 (FIG. 4 is a bottom view of the molded product, and FIG. 5 is a sectional view taken along line AA of FIG. 5) is obtained.

On the upper and lower surfaces of the molded product 7, a flat portion (reference surface) 6a1 of the upper die 1 and a flat portion (reference surface) 2 of the lower die 2 are provided.
b1 are respectively transferred, and the two transferred planes 6
The thickness of the optical element is confirmed by measuring the distance between a and 2b. Thereafter, the molded article 7 including the two optical elements is cut from the center thereof to separate the optical elements one by one.

The separated molded product 7 is centered on the basis of the outer diameter of the optical function surface (inclined surface) 6c of the optical element included in each of the molded products 7, and is processed and finished to a desired outer diameter as shown in FIGS. An optical element 6 as shown in FIG. 7 is obtained.

According to the present embodiment, the reference surfaces 6a1, 6a
By measuring the interval of b1, the mold interval can be set with high accuracy, and the plurality of optical elements 6 included in the molded article 7 are also transferred from the molding surfaces of the upper and lower dies 1, 2. By measuring the distance between the planes (reference planes) 6a and 2b, the thickness can be confirmed.
An optical element 6 having a high-precision thickness can be obtained, an optical element having the same outer diameter accuracy as the conventional one can be obtained, and the molding efficiency can be improved.

[0028]

Second Embodiment FIGS. 8 to 11 show a second embodiment of the present invention. In the case of this embodiment as well, as in Embodiment 1, for the purpose of molding the optical element 6 shown in FIGS. 6 and 7, as shown in FIG. The optical function surfaces 6c1 are arranged at four equally spaced positions with respect to the optical axis thereof, and a flat portion 2b1 is provided at a portion other than the optical function surface portion 6c1 to connect the top portions 2c thereof.
Other molding methods and configurations of molding dies are described in Example 1.
The description is omitted here.

Reference surfaces 6a1, 2b1 of the upper and lower dies 1, 2
10 and 11 (FIG. 10 is a bottom view of the molded product 8, FIG. 11).
The molded product 8 as shown in FIG.

On the upper and lower surfaces of the molded product 8, a flat portion (reference surface) 6a1 of the upper die 1 and a flat portion (reference surface) 2 of the lower die 2 are provided.
Since b1 has been transferred, the thickness of the four optical elements 6 included in the molded article 8 can be checked at the same time by measuring the distance between the two opposing parallel planes.

According to this embodiment, molding or measurement of four optical elements can be performed simultaneously, so that the molding and measurement efficiency can be further improved as compared with the first embodiment. Further, since the optical function molding surfaces are arranged at equal intervals, the heat distribution of the entire molded product 8 becomes uniform, and the quality can be improved.

[0032]

Third Embodiment FIGS. 12 to 15 show a third embodiment of the present invention. In the case of this embodiment, as shown in FIGS. 14 and 15 (FIG. 14 is a plan view of the optical element, FIG. 15 is a side view of the same), it has a columnar shape, the upper optical function surface 9a has a curved surface, and the lower surface has a curved surface. The optical axis 9c of the side optical function surface 9b is
The optical element 9 which is a circular and flat optical function surface inclined with respect to the optical axis 9d of FIG.

For this purpose, the lower mold surface 2a of the first embodiment is used.
As shown in FIG. 12, two inclined optical function surface portions 9b are arranged equiangularly with respect to the optical axis thereof, and a plane portion connecting the surface top portions 2c to each other other than the optical function surface portion 9b ( Reference surface) 2b1 is provided.

As shown in FIG. 12, on the molding surface of the upper die 1, two curved optical function surface portions 1b are formed, and a flat portion (reference surface) 1a1 is provided on a portion other than the optical function surface portion 1b. The distance between the dies is set while measuring the distance between the reference surfaces 1a1 and 2b1 of the upper and lower dies 1, 2.

If the optical axes of the upper and lower dies 1 and 2 are displaced from each other, no good optical element can be obtained. Therefore, as shown in FIG.
And align the axes.

The molded product 10 including the two optical elements shown in FIG. 13 is molded by the upper and lower dies 1 and 2 having the above-described structure.
Since the flat portion 1a1 of the upper die 1 and the flat portion 2b1 of the lower die 2 are transferred to the upper and lower surfaces of the molded product 10, respectively.
By measuring the distance between the reference surfaces, the thicknesses of the two optical elements can be checked at the same time.

After confirming the thickness of the molded article 10, the molded article 1
0 is separated from its center, and two optical elements are cut out and processed into a desired optical element 9.
When the optical function surface is a spherical surface as in this embodiment, the centering can be performed based on the spherical surface.

The other forming method and structure are the same as those of the first embodiment, and the description is omitted.

According to the present embodiment, molding or measurement of the thickness of a plurality of optical elements can be performed at the same time even if the surface on which the optical function surface is not inclined is a curved surface.

[0040]

According to the present invention, it is possible to mold a highly accurate optical element by setting the mold spacing while measuring the spacing between the reference surfaces provided on the molding surfaces of the upper and lower molds. The thickness of the optical element can be easily and accurately confirmed by measuring the distance between the reference surfaces of the molded product transferred from the molding surfaces of the upper and lower dies to the molded product. Further, since the molding or the thickness measurement of a plurality of optical elements is performed simultaneously, the efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical element molding apparatus according to a first embodiment of the present invention.

FIG. 2 is a plan view of a lower die showing the first embodiment of the present invention.

FIG. 3 is a sectional view taken along the line AA in FIG.

FIG. 4 is a bottom view of a molded product according to the first embodiment of the present invention.

FIG. 5 is a sectional view taken along line AA of FIG.

FIG. 6 is a plan view of an optical element molded by the molding method according to the first embodiment of the present invention.

FIG. 7 is a side view of the same.

FIG. 8 is a plan view of a lower die showing a second embodiment of the present invention.

FIG. 9 is a sectional view taken along line AA of FIG.

FIG. 10 is a bottom view of a molded product according to the second embodiment of the present invention.

FIG. 11 is a sectional view taken along line AA of FIG.

FIG. 12 is a sectional view using a positioning ring in a molding die according to a third embodiment of the present invention.

FIG. 13 is a bottom view of a molded product according to the third embodiment of the present invention.

FIG. 14 is a plan view of an optical element molded by a molding method according to a third embodiment of the present invention.

FIG. 15 is a side view of the same.

FIG. 16 is a plan view of an optical element for which accurate wall thickness measurement cannot be performed by a conventional technique.

FIG. 17 is a side view of the same.

FIG. 18 is a sectional view of the same.

[Explanation of symbols]

 Reference Signs List 1 upper die 2 lower die 3 transfer member 4 glass material 5 transfer arm 6,9 optical element 7,8,10 molded product 11 positioning ring

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuyoshi Iwasaki 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industrial Co., Ltd. (56) References JP-A-62-207729 (JP, A) JP-A-1-208334 (JP, A) JP-A-5-85754 (JP, A) JP-A-5-178631 (JP, A) JP-A-5-301727 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) C03B 9/00-17/06

Claims (3)

(57) [Claims] 1. A method for molding an optical element, which comprises press-molding a heat-softened optical element material with a pair of molding dies, wherein each of the molding surfaces of the pair of molding dies is provided on a portion other than the optical function surface portion. The distance between the pair of molding dies is measured by measuring the distance between the reference surfaces with the flat surface portion as a reference surface, and the optical element material is pressed and molded by the pair of molding dies. A method for molding an optical element. 2. A method for molding an optical element, comprising press-molding a heat-softened glass material with a pair of molding dies, wherein the optical element is provided on a portion of the molding surface of the molding die other than the optical functional surface portion. With the flat portion as the reference surface, the interval between the molding dies is set while measuring the interval between the reference surfaces of both the molding dies, and then the glass material is supplied between the pair of molding dies. A method for forming an optical element, comprising performing pressure molding. 3. A molding die for an optical element for molding an optical element, wherein a plurality of optical function surface portions for molding an optical function surface of the optical element are formed on a molding surface of the mold, and A molding die for an optical element, wherein a reference surface composed of a flat portion is provided on a molding surface other than the optical function surface portion.