JP3134173B2 - Optical glass mold and optical glass molding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical glass molding die and an optical glass for forming a high-precision optical glass element and a material such as a lens, a prism, and a molding glass material used in optical equipment by an ultra-precision glass molding method. It relates to a molding method.

[0002]

2. Description of the Related Art In recent years, many attempts have been made to form a high-precision optical lens, particularly an aspherical glass lens, by one-shot molding without a polishing step, and it is being put to practical use. As one of the forming methods, a method of heating a supplied glass material processed into a desired shape to a deformable temperature, for example, a temperature near a softening point, and forming the material using a method such as press forming (for example, Published Japanese Utility Model Application No. 61-21927)
There is. In this method, a molding die and a molding method having a highly accurate surface shape and structure are required.

A conventional optical glass molding die and an optical glass molding method will be described below with reference to the drawings.

FIGS. 7 (a), 7 (b) and 7 (c) show steps of forming an optical glass element by molding a supply glass material having a plano-convex shape using a conventional optical glass molding die. In the figure, 48 is an upper mold, 49 is a lower mold, 50a is a barrel mold, 50b is an optical glass element outer diameter transfer surface, 50c is a lower mold sliding surface, 51
Is a thickness regulating cylinder, 52a is a supply glass material, 52b is a molded optical glass element, and 46 and 47 are parts of a press head provided with a heating and pressing mechanism.

Next, the operation of the mold composed of the above members will be described. The glass material 52a whose weight and shape are adjusted is supplied to a space (shown in FIG. 7A) formed by the upper mold 48, the lower mold 49, and the body mold 50a, and the press head 46 provided with a heating and pressing mechanism. , 47. Glass material 5
When 2a reaches a deformable temperature, the press head 46 is lowered to start pressurizing. As the pressing is performed, the glass material 52a starts to be deformed, and the molding surface and the outer diameter surface are gradually transferred from the mold. The outer diameter portion of the glass material 52a is partially transferred. That is, when the glass material 52a reaches the optical glass element outer diameter transfer surface 50b on the inner wall of the body mold 50a,
FIG. 7 shows a state in which the body mold 50a and the glass material 52a are in close contact with each other.
The deformation further proceeds as shown in FIG. The deformation of the upper and lower surfaces of the glass material 52a at this time is affected by the shapes of the molding surfaces of the upper mold 48 and the lower mold 49, and the side surface of the glass material 52a deforms while being in close contact with the body mold 50a. Body type 50
In FIG. 7A, when the press head 46 comes into contact with the thickness regulating body mold 51 and the pressing deformation is completed, it moves to the position shown in FIG. 7C and stops. After the pressing deformation is completed, the upper mold 48 and the lower mold 4
9, body mold 50a, thickness regulating body mold 51, optical glass element 5
Cool 2b slowly. When the optical glass element 52b is cooled to a temperature at which the optical glass element 52b can be taken out, the upper mold 48 is raised to open the mold, and the optical glass element 52b is taken out.

[0006]

However, in the conventional optical glass molding die and molding method as described above, in the pressing and deforming step, a part of the glass material 52a is partially removed from the body die 50a.
When the inner wall of the optical glass element comes into contact with the outer diameter transfer surface 50b of the optical glass element, the deformation further proceeds in a state of being in close contact with the body mold, and the body mold 50a moves together with the deformation of the supply glass material 52a, and the body before pressurization deformation It will be different from the position of the mold 50a. When the position of the trunk die 50a changes, the position of the lower die sliding surface 50c of the trunk die inner wall moves upward, and a part of the outer diameter of the optical glass element 52b is also transferred and formed at this position. The phenomenon that the surface state of the lower die sliding surface 50c becomes extremely poor due to oxidation or the like is observed. When molding is continued several times, glass adheres to the body mold at the outer diameter portion of the optical glass element in contact with the lower mold sliding surface 50c, and the molded optical glass element 52b becomes poor in appearance and yield. Make you worse. Further, a step of removing the glass adhered to the inner wall of the barrel mold is required, which has a problem that productivity is adversely affected.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and when molding a glass material, the barrel does not move in accordance with the deformation of the glass material, the appearance and surface accuracy are excellent, and the optical glass molding with high productivity is achieved. It is an object of the present invention to provide a mold and an optical glass molding method.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method in which a positional relationship between a body die and a lower die before press deformation and a positional relationship between the drum die and the lower die after pressurization are completed are the same. The molding is performed while restricting the position of the body die.

Also, a molding die having a lower die sliding surface and a contact support surface in contact with a surface facing the lower die molding surface on the body die, or an outer diameter portion of an optical glass element in which the lower die is slidably housed. And a molding die having a second drum having a support surface for transmitting the pressing force to the first drum.

In addition, the upper die, the lower die, and the die are separately controlled in pressure and temperature while controlling the position of the die.

[0011]

By using the molding method and the molding die as described above, the molding die can be prevented from moving and the lower sliding surface of the inner wall of the molding die can be formed without contacting the outer diameter portion of the optical glass element. Glass is no longer attached to the barrel mold.

Further, in a mold having a second body die for transmitting a pressing force to the first body die, the first body die moves until the pressing deformation, and the lower mold sliding surface has an optical glass. Although the contact is made with the outer diameter portion of the element, when the pressurization is completed, the position of the first barrel mold can be regulated by the second barrel mold so as not to make contact, so that the glass does not adhere.

Further, by using a molding method in which the upper mold, the lower mold and the body mold are individually heated and pressed, not only the position of the body mold can be regulated, but also more molding conditions can be set, and various conditions can be set. Optimal temperature and pressure conditions can be given to each part with respect to the shape of the optical glass element, and the range of molding conditions can be expanded.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical glass molding die and an optical glass molding method according to one embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 shows a state of an optical glass forming die and an optical glass element after completion of forming a glass material by an optical glass forming method according to a first embodiment of the present invention. In the drawing, reference numerals 1 and 2 denote a part of a press head having a heating and pressing mechanism, 3 denotes an upper die, 4 denotes a lower die, 5a denotes a trunk die, 5b denotes a lower die sliding surface, and 6 denotes a molded optical glass. The element 7 is a part of the barrel-type fixed head.

Next, the operation of the optical glass molding die constituted by the above members will be described. The lower mold 4 is slidably stored in the lower part of the body mold 5a, and a glass material is placed on the lower mold 4. Thereafter, the upper mold 3 is inserted from above the body mold 5a, and is set between the press heads 1 and 2. Thereafter, the press heads 1 and 2 having the heating and pressing mechanism are brought into contact with the upper mold 3 and the lower mold 4, and the heat of the press heads 1 and 2 heats the upper mold 3 and the lower mold 4. The glass material and the barrel mold 5a are heated via upper and lower molds 3 and 4. When the temperature of the glass material reaches a deformable temperature, the barrel mold fixing head 7 clamps and fixes the barrel mold 5a to regulate the position. After that, the upper die 3 is moved by a predetermined amount by the press head 1 to perform pressure deformation.

In the pressing and deforming step, the glass material is gradually deformed, and when the side end of the glass material reaches the inner wall of the body die, the body die 5a is lifted by the shape of the optical glass element, that is, the shape of the molding surface. The force which tries to be generated. However, since the position of the barrel mold 5a is regulated by the barrel mold fixed head 7, the glass material continues to deform without moving upward. After the pressure deformation is completed, the torso fixed head 7
Releases the restriction on the position of the torso. Then, upper and lower mold 3,
4. When the molded optical glass element 6 and the barrel mold 5a are gradually cooled to reach a temperature at which the optical glass element 6 can be taken out, the press head 1 is opened, the upper mold 3 is opened, and the optical glass element 6 is taken out.

According to this molding die, the barrel die does not move as the supply glass material is deformed in the heating step, the pressing deformation step, and the cooling step. Therefore, the outer diameter portion of the optical glass element does not come into contact with the lower die sliding surface 5b of the inner wall of the trunk die, so that glass does not adhere to the lower die sliding surface 5b. Therefore, a good optical glass element can be obtained.

In this embodiment, the position of the torso 5a is restricted by the torso fixed head 7, but the position of the torso may be restricted by another method. Further, the position of the drum may be regulated not only in the pressing and deforming step but also in the heating step and the cooling step.

(Embodiment 2) FIG. 2 shows a state of an optical glass mold and an optical glass element after a glass material is pressed by using an optical glass mold according to a second embodiment of the present invention and deformation is completed. . In the figure, reference numerals 8 and 9 denote a part of the press head provided with a heating / pressing mechanism, 10 denotes an upper die, 11 denotes a lower die, 12a denotes a trunk die, 12b denotes a lower die sliding surface, 12c denotes a contact support surface, and 13 denotes a contact surface. Is a molded optical glass element.

Next, the operation of the optical glass molding die constituted by the above members will be described. The lower mold 11 is slidably stored in the body mold 12a, a glass material is placed on the lower mold 11, and then the upper mold 10 is arranged. The body mold 12 a has a lower mold sliding surface 12 b with the lower mold 11 and a contact support surface 12 c having the same shape as the surface facing the molding surface of the lower mold 11, and is in contact with the lower mold 11. Thereafter, a press head 8 having a heating and pressing mechanism,
The upper mold 10 and the body mold 12a are directly heated by contacting with the mold 9, and the lower mold 4 and the glass material are heated via the body mold 12a and the upper mold 3. When the temperature of the supplied glass material reaches a deformable temperature, the press head 8 performs pressure deformation.

In the pressing and deforming step, the glass material is deformed, and when the side end of the glass material reaches the inner wall of the body die, the shape of the optical glass element, that is, the shape of the forming surface of the mold, causes the body mold 12a to be deformed. The force which tries to lift up arises. However, the contact support surface 12c of the body mold 12a is
Since the body mold 12a is in contact with the bottom surface of the first glass body 1, the supply glass material is deformed under pressure without moving. After the completion of the pressure deformation, the upper and lower dies 10, 11, the molded optical glass element 13, and the body mold 12a are gradually cooled. When the temperature reaches a temperature at which the upper mold 10 can be taken out, the press head 8 is opened, and the upper mold 10 is opened.
The optical glass element 13 is taken out.

In the cooling step as well as the temperature raising step and the pressure deformation step, the barrel mold 12a does not move upward due to the deformation of the glass material. Therefore, the outer diameter portion of the optical glass element comes into contact with the lower mold sliding surface 12b of the inner wall of the body mold having a poor surface condition, so that no transfer is formed and no glass adheres. As a result, an optical glass element having good appearance and shape accuracy can be obtained.

In the present embodiment, the contact support surface of the body mold has a flat shape. However, the shape of the contact support surface of the body mold may be any shape as long as it matches the bottom shape of the lower mold. But it goes without saying that there is no problem. In addition, the thickness of the optical glass element is regulated by means other than the press head. In other words, there is no problem at all even when the thickness regulating cylinder is provided.

(Embodiment 3) FIG. 3 shows the state of the optical glass mold and the optical glass element after the glass material is pressed by using the optical glass mold of the third embodiment of the present invention and the deformation is completed. . In the figure, 14 and 15 are parts of a press head provided with a heating and pressing mechanism, 16 and 17 are upper and lower dies, 18a is a barrel type, 18b is a lower die sliding surface, 18c is a contact support surface, 18d
Is a through-hole, 19 is a thickness-regulating barrel, and 20 is a molded optical glass element.

An optical glass element 20 is obtained through a heating step, a pressure deformation step, and a cooling step in the same manner as in the second embodiment, using the optical glass mold composed of the above members.

This embodiment is different from the second embodiment in that the body mold 18a has a lower mold sliding surface 18b, a contact support surface 18c in the form of a part of a conical surface, and a through hole 18d. And the bottom surface of the lower mold 17 is in direct contact with the press head 15. Further, the thickness of the optical glass element 20 is not regulated by the press head 14 but is regulated by the thickness regulating cylinder 19.

The provision of the contact support surface 18c on the body mold 18a has the same effect as in the second embodiment, that is, the body mold 1a can be used in the cooling step as well as in the temperature raising step and the pressure deformation step.
8a does not move. Therefore, the outer diameter portion of the optical glass element is not transferred and formed by the lower die sliding surface 18b of the barrel inner wall, glass does not adhere to the barrel inner wall, and an optical element having a good appearance and shape accuracy. A glass element is obtained.

In the third embodiment, the contact support surface of the body mold is a part of a conical surface shape similar to that of the lower mold. However, the shape of the contact support surface of the body mold is different from that of the lower mold. At least a portion of the contact support surface of the body mold, such as a shape that matches the shape of the part that comes into contact with the surface, a combination shape where the lower mold makes point contact with the body contact support surface, It goes without saying that there is no problem as long as the shape is such that it can always come into contact with and support the device.

Further, by providing a through hole 18d in addition to the body mold 18a, the lower mold 17 comes into direct contact with the press head 15, and unlike the second embodiment, the lower mold 17 and the supply glass are not interposed through the body mold. Since the material can be heated and cooled, the heat transfer efficiency is improved.

(Embodiment 4) FIGS. 4 (a) and 4 (b) show steps of forming an optical glass element by molding a glass material with an optical glass mold according to a fourth embodiment of the present invention. . In the figure, reference numerals 21 and 22 denote a part of a press head provided with a heating / pressing mechanism, 23 denotes an upper die, 24 denotes a lower die, 25a denotes a first die, 25b denotes a lower die sliding surface, and 26a denotes a second die. Mold, 26b is a support surface, 27a is a supply glass material in a deformation process, 2
7b is a molded optical glass element.

Next, the operation of the optical glass mold formed of the above members will be described. The first body mold 25a is slidably inserted into the lower mold 24, and the glass material is placed on the lower mold 24. Thereafter, the upper mold 23 and the second body mold 26a are inserted and arranged from above. The second body mold 26a has a stepped support surface 26b so as to be able to contact the upper surface of the first body mold 25a.
Then, press heads 21 and 22 each having a heating and pressing mechanism are provided.
The upper and lower molds 23 and 24 are directly heated by contact with the glass material, the first body mold 25a and the second body mold 26a
Heating takes place via 24. In consideration of the coefficient of thermal expansion of the material of the first body mold 25a and the upper and lower molds 23 and 24, the bottom position dimension of the second body mold is different from that of the press head 21 at normal temperature as shown in FIG. The dimensions are such that some space is provided between them. If the coefficients of thermal expansion are the same, no space is needed. When the glass material reaches a deformable temperature, the press head 21 is lowered to perform pressure deformation.

In this pressurizing step, the supply glass material is deformed, and when the side end of the glass material reaches the inner wall of the first barrel mold, the shape of the optical glass element, that is, the shape of the molding surface of the mold, causes A force for lifting the one-body mold 25a is generated. By this force, as shown in FIG. 4A, the first body mold 25a moves together with the second body mold 26a that has been arranged in contact, that is, floats. However, when the pressing deformation of the glass material is completed, the upper surface of the second body mold 26a is pressed by the press head 21, and the first body mold 25a is also pressed via the support surface 26b of the second body mold 26a. FIG. 4 (b)
As shown in (1), the first barrel mold 25a returns to the original position before pressurization. After the completion of the pressure deformation, the upper and lower dies 23 and 24, the formed optical glass element 27, the first body mold 25a, and the second body mold 26a
Is gradually cooled to a temperature at which it can be taken out, the press head 21 is opened, the upper mold 23 is opened, and the optical glass element 2 is opened.
Take out 7.

During the pressure deformation, the first barrel mold 25a moves upward due to the deformation of the supply glass material, and a part of the outer diameter portion of the optical glass element is moved by the lower sliding surface 25b of the barrel inner wall. Is transferred and formed when the pressure deformation is completed.
The first body mold 25a moves downward through the support surface 26b of the lower mold 6a, returns to the position before the pressure deformation, and slides on the lower mold surface 25b.
And the contact with the outer diameter portion of the optical glass element is eliminated. As described above, when the lower die sliding surface 25b of the first body mold 25a is not in contact with the outer diameter portion of the optical glass element when the pressing deformation is completed, the outer diameter portion of the optical glass element is transferred in the pressing deformation process. Even if it is formed, adhesion of glass to the first barrel mold 25a does not occur.

As described above, at least when the pressing deformation is completed, the positional relationship between the lower sliding surface of the lower die of the first barrel type and the positional relationship between the lower sliding surface of the lower die before the pressing deformation and the lower die are determined. By using a mold having the same relationship, an optical glass element having good appearance and transferability can be obtained without adhesion of glass.

In the present embodiment, the support surface of the second body die has a planar shape. However, the shape of the support surface of the second body die may be the same as the shape of the contact portion with the first body die. Even if the shape is such that only a part of the shape is in contact, there is no problem as long as the shape of the first body is pressurized and movable by the second body when the pressing deformation is completed.

(Embodiment 5) FIG. 5 shows a state where an optical glass element is formed by molding a glass material using an optical glass mold according to a fifth embodiment of the present invention. In the figure, 28, 29
Is a part of a press head provided with a heating / pressing mechanism, 30 is an upper die, 31 is a lower die, 32a is a first die, 32b is a lower die sliding surface, 33a is a second die, and 33b is a support surface. And 34 are molded optical glass elements.

As in the fourth embodiment, an optical glass element 34 is obtained through a heating step, a pressure deformation step, and a cooling step.

Unlike the molding die used in the fourth embodiment, the second body die 33a of the molding die of this embodiment has a structure having three kinds of inner diameters. Since the support surface 33b of the two-body mold 33a presses the upper surface of the first body mold 32a, the first body mold does not move similarly to the molding mold of the fourth embodiment.

(Embodiment 6) FIG. 6 shows the state of an optical glass mold and an optical glass element when a glass material is completely deformed under pressure using the optical glass mold of the sixth embodiment of the present invention. Show. In the figure, 35 and 36 are part of the press head for the upper and lower molds provided with the heating and pressing mechanism, 37 and 38 are the parts of the press head for the first body mold having the heating and pressing mechanism, 39,
40 is a part of the press head for the second body mold provided with the heating and pressing mechanism, 41 is the upper mold, 42 is the lower mold, 43a is the first body mold, 4a
3b is a lower mold sliding surface, 44 is a second body mold, and 45 is a molded optical glass element.

Next, the operation of the optical glass molding die constituted by the above members will be described. The first body mold 43a is slidably inserted into the lower mold 42 from above, the glass material is placed on the lower mold 42,
Thereafter, the second body mold 44 and the upper mold 41 are sequentially arranged. After that, the complete set of molds is moved and arranged on the press head.
The press head includes upper and lower dies 41 and 42, a first trunk die 43a,
The mechanism is such that the temperature and pressurization can be controlled independently for each of the second barrel dies 44. When a set of molding dies is placed on the press head, the upper and lower press heads 35 and 36 move the upper and lower dies 41 and 42 to the first body press heads 37 and 3.
8 presses the first cylinder die 43a to the second cylinder press heads 39, 4
0 sandwiches the second body molds 44 respectively. In this state, it is heated to a desired temperature through the press heads of the respective parts. When the desired temperature is reached and the supply glass material becomes deformable, pressurization is performed by the upper die press head 35 to deform the supply glass material. In this pressure deformation step, the supply glass material is deformed, and when the side end of the glass material reaches the inner wall of the first barrel mold, the shape of the optical glass element, that is, the shape of the forming surface of the molding die, causes the first barrel to be deformed. A force for lifting the mold 43a is generated. Thereby, the first body mold 43
a is moving, that is, trying to float up, but the press heads 37 and 38 for the first body mold press and fix the first body mold 43a,
Since the position of the first trunk die 43a is regulated, it does not move. After the completion of the pressure deformation, the upper and lower dies 41 and 42, the formed optical glass element 45, the first body mold 43a, and the second body mold 44 are gradually cooled by each press head to reach a temperature at which it can be taken out. Is opened, the upper mold 41 is opened, and the optical glass element 45 is taken out.

By using a molding method in which the upper, lower, first and second body dies are individually pressed, the sliding surface of the lower mold can be used in any of the heating step, the pressure deformation step, and the cooling step. The position of the first body mold that is provided can be regulated. Therefore, the first glass mold does not move due to the shape of the optical glass element, and the outer diameter portion of the optical glass element is not transferred and formed by the lower mold sliding surface. The production of an optical glass element having a stable and good appearance and surface shape without generation of blemishes becomes possible.

At the same time, since a molding method for individually controlling the temperature of the upper, lower, first and second barrel dies is used, more molding conditions can be set. For example, in the case of an optical glass element having an uneven thickness ratio, in the heating step, the temperature gradient is increased as compared with the thin portion, or the temperature is increased so that the temperature of the thick portion is quickly raised. In the cooling step, it is possible to rapidly cool a thick part in comparison with a thin part. That is, optimum temperature conditions can be given to each part for various shapes of optical glass elements, and the range of molding conditions can be expanded.

In the molding dies of the embodiments, the second body mold is arranged and used for keeping the temperature of the first body mold. However, any molding mold can be formed by the method of the present invention. Alternatively, the number of individually controllable press mechanisms may be changed according to the structure of the molding die. Also, there is no problem if the molding method of the present invention is used in a molding step in which each step is divided, as well as in a case where the temperature is raised, pressed, and cooled by one press head.

[0045]

As is clear from the above description of the embodiments, according to the optical glass molding die and the optical glass molding method of the present invention, at least the pressure deformation can be performed without being affected by the shape of the optical glass element. The relative position of the former die and the lower die becomes the same relative position of the die and the lower die after the completion of the pressure deformation. Furthermore, since the outer diameter portion of the optical glass element does not come into contact with the lower die sliding surface of the inner wall of the barrel die, it is possible to prevent glass from adhering to the lower die sliding surface, and has a good appearance and shape accuracy. Optical glass elements can be produced with good yield.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state at the time of completion of molding of an optical glass mold and an optical glass element according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state at the time of completion of molding of an optical glass mold and an optical glass element of Example 2;

FIG. 3 is a cross-sectional view showing a state at the time of completion of molding of the optical glass mold and the optical glass element of Example 3;

FIG. 4 is a cross-sectional view showing a state at the time of completion of molding of the optical glass mold and the optical glass element of Example 4;

FIG. 5 is a cross-sectional view showing a state at the time of completion of molding of the optical glass mold and the optical glass element of Example 5;

FIG. 6 is a cross-sectional view showing a state at the time of completion of molding of the optical glass mold and the optical glass element of Example 6;

FIG. 7 is a cross-sectional view showing a state during a molding process of a conventional optical glass mold and an optical glass element.

[Explanation of symbols]

1,8,14,21,28,35 Upper die press head 2,9,15,22,29,36 Lower die press head 3,10,16,23,30,41 Upper die 4,11,17 , 24, 31, 42 Lower mold 5a, 12a, 18a Body mold 5b, 12b, 18b, 25b, 32b, 43b Lower mold sliding surface 6, 13, 20, 20, 27, 34, 45 Optical glass element 7 Body fixed head 12c, 18c Contact support surface 18d Through hole 19 Thickness control drum 25a, 32a, 43a First drum 26a, 33a, 44 Second drum 26b, 33b Support surface 37, 38 Press head 39, 40 for first drum Press head for second cylinder

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C03B 11/16 C03B 11/00 C03B 11/08 C03B 11/12

Claims (9)

(57) [Claims] Claims: 1. In a press forming in which a glass material is supplied to a space formed by a pair of a forming die and a body mold, and the temperature is increased by pressurization, at least the relative positions of the lower mold and the body mold at the time of completion of the press deformation are: An optical glass molding die that regulates the position of the barrel so that it is at the same relative position as the lower mold and the barrel before pressure deformation. 2. The optical glass mold according to claim 1, wherein the body mold is provided with a lower mold sliding surface and a contact support surface in contact with a surface facing the lower mold molding surface. 3. The optical glass mold according to claim 2, wherein the shape of the contact support surface is a flat surface or a part of a conical surface. 4. The optical glass mold according to claim 1, wherein a through-hole is provided in a lower part of the body in a sliding direction of the mold. 5. A second body die having a support surface for slidingly housing a molding die, making contact with a first body die forming an outer diameter portion of the optical glass element, and having a support surface for transmitting a pressing force to the first body die. The optical glass mold according to claim 1. 6. The optical glass mold according to claim 5, wherein at least the inside of the second barrel mold has a stepped shape and is constituted by two or more different inner diameters. 7. A press-forming method in which a glass material is supplied to a space formed by a pair of a forming die and a body mold, and then the temperature is increased by pressurization. An optical glass molding method for molding while regulating the position of the body die so as to be at the same relative position as the lower mold and the body mold before the pressure deformation. 8. In a press forming in which a glass material is supplied to a pair of forming dies and a body mold, and then the temperature is increased and pressurized, the relative position of the lower mold and the body mold at least at the time of completion of the pressure deformation is changed before the pressure deformation. An optical glass forming method in which the position of the body die is regulated so as to be the same as the relative position of the lower die and the body die, and the temperature and pressure of the forming die and the body die are separately controlled. 9. The optical glass forming method according to claim 8, wherein the position of the barrel mold is regulated by a pressing force in the same direction as the sliding direction of the mold.