Patent Application
20210002161
The present disclosure relates to a method of molding an optical element and optical element molding molds.
A molding method, in which a glass material that is a molding material is heated and press molded by means of molds to transfer forms of the molds to the glass material, as disclosed in JP2003292327A, for example, has been known as one method of molding an optical element, such as a glass lens. This molding method for an optical element enables the cost including that for any downstream process to be reduced, by molding of, in addition to optically functional surfaces provided on upper and lower surfaces of the optical element, a side surface of the optical element, together at once.
According to one aspect of the present disclosure, there is provided a method of molding an optical element, the method including: preparing a molding material; preparing: an upper mold having an upper surface molding surface provided on an end portion of a neck portion of the upper mold; a lower mold having a lower surface molding surface provided on an end portion of a neck portion of the lower mold; and a side mold having a side surface molding surface provided on an inner surface of a hole portion of the side mold; inserting the neck portion provided in the upper mold and the neck portion provided in the lower mold into the hole portion provided in the side mold; positioning a distal end of the neck portion of the lower mold below an opening rim of the hole portion of the side mold, and ejecting oxygen that is in the molds through a gap formed between the opening rim of the hole portion of the side mold and the molding material that has been placed on the lower surface molding surface; heating up the molding material; and press molding the molding material by bringing the upper mold and side mold, and the lower mold, closer to each other.
According to another aspect of the present disclosure, there is provided an optical element molding mold including: an upper mold having a neck portion; a lower mold having a neck portion; a side mold having, provided therein, a hole portion where the neck portions of the upper mold and the lower mold are inserted; an upper surface molding surface provided on an end portion of the neck portion of the upper mold; a lower surface molding surface provided on an end portion of the neck portion of the lower mold; and a side surface molding surface provided on an inner surface of the hole portion of the side mold, wherein at a first position where a gap between a distal end of the neck portion of the lower mold and an opening rim of the side mold becomes the largest, before or after a molding operation in a state where the optical element molding mold has been fitted in a molding machine, the gap is smaller than a thickness of a molding material that has been placed on the lower surface molding surface.
According to still another aspect of the present disclosure, there is provided an optical element molding mold including: an upper mold having a neck portion; a lower mold having a neck portion; a side mold having, provided therein, a hole portion where the neck portions of the upper mold and the lower mold are inserted; an upper surface molding surface provided on an end portion of the neck portion of the upper mold; a lower surface molding surface provided on an end portion of the neck portion of the lower mold; and a side surface molding surface provided on an inner surface of the hole portion of the side mold, wherein at a first position where a gap between a distal end of the neck portion of the lower mold and an opening rim of the side mold becomes the largest, before or after a molding operation in a state where the optical element molding mold has been fitted in a molding machine, the gap is smaller than a side surface thickness of an optical element.
The above and other features, advantages and technical and industrial significance of this disclosure will be better understood by reading the following detailed description of the disclosure, when considered in connection with the accompanying drawings.
Embodiments of a method of molding an optical element and an optical element molding mold, according to the present disclosure will be described below while reference is made to the drawings. The present disclosure is not limited to the following embodiments, and components in the following embodiments include any component that is easily substitutable by a person skilled in the art, or any component that is substantially the same.
A molding apparatus 1 molds an optical element, for example, a glass lens, by press molding a molding material (for example, a glass material) M that has been softened by heating. The molding apparatus 1 mainly includes, as illustrated in
At the mold supply unit 11, a mold supplying process of supplying a mold 20 before molding to the molding apparatus 1, and a mold ejecting process of ejecting the mold 20 after the molding from the molding apparatus 1, are performed. The mold supply unit 11 has, provided therein, a placement unit 111 for placement of the mold 20 that has been conveyed by a conveying mechanism not illustrated in the drawings.
At the oxygen electing unit 12, an oxygen ejecting process of ejecting oxygen that is inside the mold 20 to replace the atmosphere inside the mold 20 with inert gas, such as nitrogen, is performed. The oxygen electing unit 12 has, provided therein, a placement unit 121 for placement of the mold 20 that has been conveyed by a conveying mechanism not illustrated in the drawings.
At the molding unit 13, a heating process, a press molding process, and a cooling process, are performed. The molding unit 13 has, provided therein, an upper plate 131 and a lower plate 132 that are for heating and pressing the mold 20, with the mold 20 interposed between the upper plate 131 and the lower plate 132, the mold 20 having been conveyed by a conveying mechanism not illustrated in the drawings. Each of the upper plate 131 and the lower plate 132 has, provided therein, a heating mechanism and a cooling mechanism, which are not illustrated in the drawings. Furthermore, the lower plate 132, has, provided therein, a pressing mechanism (a pressing pin) 133 for pressing a lower mold 22 in the press molding process.
A configuration of the mold (an optical element molding mold) 20 according to an embodiment will be described while reference is made to
An upper mold 21 includes a neck portion 211 that extends toward the lower mold 22, the neck portion 211 being columnar. This neck portion 211 of the upper mold 21 is a portion to be inserted into a hole portion 231 of the side mold 23. An end portion of the neck portion 211 has, provided thereon, an upper surface molding surface 212 for molding an optically functional upper surface of an optical element.
The lower mold 22 includes a neck portion 221 that extends toward the upper mold 21, the neck portion 221 being columnar. This neck portion 221 of the lower mold 22 is a portion to be inserted into the hole portion 231 of the side mold 23. An end portion of the neck portion 221 has, provided thereon, a lower surface molding surface 222 for molding an optically functional lower surface of an optical element.
The lower mold 22 is configured to, as described later, enable a distal end of the neck portion 221 of the lower mold 22 to be positioned at a position (hereinafter, referred to as a “first position”) lower than an opening rim 233 of the hole portion 231 of the side mold 23. The “distal end of the neck portion 221 of the lower mold 22” specifically means an outer peripheral rim 223 at a distal end of the neck portion 221 of the lower mold 22 illustrated in
The side mold 23 has, provided therein, the hole portion 231 vertically penetrating the side mold 23. An inner surface of this hole portion 231 has, provided thereon, a side surface molding surface 232 for molding a side surface of an optical element. The upper mold 21 and the lower mold 22 are disposed at positions where their molding surfaces face each other, with the side mold 23 interposed between the upper mold 21 and the lower mold 22. Furthermore, the upper mold 21, the lower mold 22, and the side mold 23 are disposed inside the sleeve 24.
The sleeve 24 is for housing therein the upper mold 21, the lower mold 22, and the side mold 23. The sleeve 24 has a cylindrical shape. Furthermore, the sleeve 24 has, formed therein, vents 241 and 242, through which the interior and the exterior of the sleeve 24 communicate, and which are for introducing inert gas into the mold 20 in an oxygen ejecting process of a later described method of molding an optical element.
An assembling process for the mold 20 before molding be described below. Firstly, the lower mold 22 and the side mold 23 are fitted in the sleeve 24.
Specifically, the side mold 23 is disposed on a stepped portion provided inside the sleeve 24, and the lower mold 22 is disposed such that a lower end surface of the lower mold 22 becomes coplanar with a lower end surface of the sleeve 24. As illustrated in
Subsequently, a molding material M is placed on the lower surface molding surface 222 of the lower mold 22.
The molding material M may be placed as follows. For example, before the molding material M is placed on the lower surface molding surface 222, the lower mold 22 is lifted up to a position (a position higher than the first position) where the outer peripheral rim 223 of the lower surface molding surface 222 is higher than the opening rim 233 of the side mold 23. After the molding material M has been placed on the lower surface molding surface 222 at that position, the lower mold 22 is lowered to the first position. As a result, the distance by which the molding material M is inserted into the hole portion 231 of the side mold 23 is shortened and placement of the molding material M is thus facilitated.
If the distance by which the molding material M is inserted into the hole portion 231 of the side mold 23 is long, for example, when a spherical molding material M is released from suction by a jig, which conveys the molding material M, and is dropped, the molding material M may bounce and jump out of the hole portion 231. Furthermore, if the distance by which the molding material M is inserted into the hole portion 231 of the side mold 23 is long, for example, when a lens shaped molding material M that has been processed approximately spherical is released from suction by a jig, which conveys the molding material M, and is dropped, the molding material M may rotate in the hole portion 231 and be in a wrong posture, for example, upside down.
As described above, by placing a molding material M after lifting the lower mold 22 to a position where the outer peripheral rim 223 of the lower surface molding surface 222 is higher than the opening rim 233 of the side mold 23, the molding material M is able to be prevented from lumping out or rotating.
Furthermore, the molding material M has been processed to have a diameter DM smaller than an inner diameter D231 of the hole portion 231 for the purpose of enabling press molding by the upper mold 21 and the lower mold 22 inside the hole portion 231 of the side mold 23. As a result, when the molding material M is inserted in the hole portion 231, a predetermined clearance is formed between the molding material M and the inner surface (the side surface molding surface 232) of the hole portion 231.
Subsequently, the upper mold 21 is fitted in the sleeve 24. Specifically, the upper mold 21 is placed on an upper end surface of the sleeve 24, and the neck portion 211 of the upper mold 21 is inserted in the hole portion 231 of the side mold 23.
The neck portion 221 of the lower mold 22 has been formed to be equal in length to or larger in length than the hole portion 231 of the side mold 23. Being “equal” includes a state where the length of the neck portion 221 of the lower mold 22 is the same as the length of the hole portion 231 of the side mold 23, a state where the length of the neck portion 221 of the lower mold 22 is minutely shorter than the length of the hole portion 231 of the side mold 23, and a state where the length of the neck portion 221 of the lower mold 22 is minutely longer than the length of the hole portion 231 of the side mold 23.
As a result, in a demolding process in a later described method of molding an optical element, lifting the lower mold 22 relatively to the side mold 23 in a state where the upper mold 21 has been removed (see
A first embodiment of a method of molding an optical element using the mold 20 will be described below while reference is made to
In the method of molding an optical element, an oxygen ejecting process is performed at the oxygen ejecting unit 12, after the mold 20 (see
In the oxygen ejecting process, the inside of the mold 20 conveyed to the oxygen ejecting unit 12 is filled with inert gas, such as nitrogen, to eject the oxygen that is in the mold 20 (Step S1). In the oxygen electing process, specifically, in a state where the outer peripheral rim 223 of the neck portion 221 of the lower mold 22 has been positioned at the first position lower than the opening rim 233 of the hole portion 231 of the side mold 23, the oxygen that is in the mold 20 is ejected through the clearance Cl formed between the opening rim 233 of the hole portion 231 of the side mold 23 and the molding material M that has been placed on the lower surface molding surface 222. Setting of the positional relation where the outer peripheral rim 223 of the neck portion 221 of the lower mold 22 is positioned at the first position is performed in the above described assembling process for the mold 20.
In the oxygen ejecting process, more specifically, the oxygen that is inside the mold 20 is ejected through: the vents 241 and 242 formed in the sleeve 24; and the clearance Cl formed between the opening rim 233 of the hole portion 231 of the side mold 23 and the molding material M that has been placed on the lower surface molding surface 222, and the atmosphere inside the mold 20 is replaced with the inert gas. To ensure the replacement with the inert gas in the oxygen ejecting process, the atmosphere in the oxygen ejecting unit 12 may be decompressed by a vacuum pump not illustrated in the drawings, and the inside of the mold 20 may thereafter be filled with the inert gas.
In the heating process, the mold 20 that has been conveyed to the molding unit 13 is interposed between the upper plate 131 and the lower plate 132, and the molding material M is heated up to a temperature equal to or higher than a yield point of the molding material M (Step S2).
In the press molding process, the upper mold 21 and side mold 23, and the lower mold 22 are brought closer to each other, and the molding material M is thereby press molded (Step S3). In the press molding process, specifically, as illustrated in
In the cooling process, after slowly cooling the mold 20 to a temperature equal to or lower than a transition temperature of the molding material M, the mold 20 is further cooled to a room temperature (Step S4).
In the demolding process, after the upper mold 21 has been removed from the side mold 23, by lifting the lower mold 22 by means of the pressing mechanism 133 as illustrated in
The above described method of molding the optical element O enables the oxygen in the mold 20 to be elected and replaced with the inert gas, through the clearance Cl formed between the opening rim 233 of the hole portion 231 of the side mold 23 and the molding material M that has been placed on the lower surface molding surface 222, as illustrated in
A second embodiment of the method of molding an optical element O using the mold 20 will be described below while reference is made to
Similarly to the first embodiment, in the assembling process for the mold 20 according to the second embodiment, the lower mold 22 is disposed such that the lower end surface of the lower mold 22 becomes coplanar with the lower end surface of the sleeve 24. As illustrated in
In the mold 20 according to the second embodiment, the clearance Cl is set to be smaller than a thickness TM of a molding material M. That is, when viewed in the horizontal direction as illustrated in
If the molding material M used is spherical as illustrated in
In this method of molding an optical element O according to the second embodiment, similarly to the first embodiment: the mold 20 assembled outside the molding apparatus 1 and before molding is supplied to the mold supply unit 11 of the molding apparatus 1; an oxygen ejecting process, a heating process, a press molding process, and a cooling process are performed; and a demolding process is thereafter performed outside the molding apparatus 1. The heating process, the press molding process, the cooling process, and the demolding process are similar to those according to the first embodiment and description thereof will thus be omitted.
In the oxygen ejecting process according to the second embodiment, as illustrated in
Furthermore, according to the second embodiment, this state, in which the gap G between the outer peripheral rim 223 of the neck portion 221 of the lower mold 22 and the opening rim 233 of the hole portion 231 of the side mold 23 is smaller than the thickness TM of the molding material M (or the side surface thickness TM1 of the molding material M1) that has been placed on the lower surface molding surface 222, is maintained from the placement of the molding material N onto the lower surface molding surface 222 in the assembling process until the press molding process is started.
According to the method of molding an optical element O as described above, the gap G between the outer peripheral rim 223 of the neck portion 221 of the lower mold 22 and the opening rim 233 of the hole portion 231 of the side mold 23 is made smaller than the thickness TM of the molding material M (or the side surface thickness TM1 of the molding material M1) that has been placed on the lower surface molding surface 222. Therefore, the molding material M is able to be prevented from falling off the lower surface molding surface 222 due to, for example: flow of gas generated when the oxygen is ejected to be replaced with inert gas; or minute vibration generated when the mold 20 is conveyed before press molding or when the lower mold 22 is lifted at the time of press molding. As a result, for example, the risk of performing press molding in a state where a molding material M is not on the lower surface molding surface 222 or a state where a molding material M juts out from the lower surface molding surface 222, and thereby damaging the mold 20, at the time of press molding, is able to be avoided.
A third embodiment of the method of molding an optical element O using the mold 20 will be described below while reference is made to
Similarly to the first embodiment, in the assembling process for the mold 20 according to the third embodiment, the lower mold 22 is disposed such that the lower end surface of the lower mold 22 becomes coplanar with the lower end surface of the sleeve 24. As illustrated in
In the mold 20 according to the third embodiment, this clearance Cl is made smaller than a side surface thickness TO of an optical element O that has been molded, the side surface thickness TO being a thickness of the optical element O at its side surface. That is, when viewed in the horizontal direction as illustrated in
In this method of molding an optical element O according to the third embodiment, similarly to the first embodiment: the mold 20 that has been assembled outside the molding apparatus 1 and before molding is supplied to the mold supply unit 11 of the molding apparatus 1; an oxygen ejecting process, a heating process, a press molding process, and a cooling process are performed; and a demolding process is thereafter performed outside the molding apparatus 1. The heating process, the press molding process, the cooling process, and the demolding process are similar to those according to the first embodiment and description thereof will thus be omitted.
In the oxygen ejecting process according to the third embodiment, as illustrated in
Furthermore, the state, in which the gap G between the outer peripheral rim 223 of the neck portion 221 of the lower mold 22 and the opening rim 233 of the hole portion 231 of the side mold 23 is smaller than the side surface thickness TO of the optical element O that has been molded, is maintained from the end of the press molding process until the optical element O that has been molded is taken out in the demolding process.
According to the method of molding an optical element O as described above, the gap between the outer peripheral rim 223 of the neck portion 221 of the lower mold 22 and the opening rim 233 of the hole portion 231 of the side mold 23 is made smaller than the side surface thickness TO of the optical element O that has been molded. Therefore, the optical element O is able to be prevented from falling off the lower surface molding surface 222 due to minute vibration generated when, for example the mold 20 is conveyed after press molding or the lower mold 22 is lowered after press molding. As a result, for example, the risk of performing a push-out operation (see
For example, according to the above described demolding process in the method of molding an optical element O, the upper mold 21 is removed from the mold 20 and an optical element O is taken out by lifting the lower mold 22 using the pressing mechanism 133, but the side mold 23, in addition to the upper mold 21, may be removed from the mold 20 and the optical element O may be directly taken out from the lower mold 22 without using the pressing mechanism 133.
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the disclosure in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general concept as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-069225 | Mar 2018 | JP | national |
This application is a continuation of PCT international application Ser. No. PCT/JP2019/010011 filed on Mar. 12, 2019 which designates the United States, incorporated herein by reference, and which claims the benefit of priority from Japanese Patent Applications No. 2018-069225, filed on Mar. 30, 2018, incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2019/010011 | Mar 2019 | US |
| Child | 17026358 | US |
