JPH0445457B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for manufacturing an optical element, and more particularly to a method for continuously press-molding an optical element with high precision.

[Prior Art] Conventionally, many optical elements such as lenses, prisms, and filters have been molded by a method of polishing a material for molding optical elements, such as glass. However, the polishing process requires considerable time and skill, and in particular, molding optical elements with complex shapes such as aspherical lenses requires even more sophisticated polishing techniques. It took a long time, and it was difficult to produce large quantities in a short period of time.

Therefore, a method of molding an optical element such as a lens by simply inserting and arranging an optical element molding material into a pair of molds and pressurizing the material is attracting attention.

FIGS. 1 and 2 are schematic diagrams showing conventional molds for manufacturing optical elements. 1 is an upper mold for molding one functional surface of the optical element. The surface 1a that contacts the functional surface of the optical element is finished as a mirror surface. 2 is the lower mold,
Molding the opposite functional surface of the optical element. The surface 2a of the lower mold 2 is also finished to a mirror surface. 3 is a molding material, 4 is a molded optical element, 5 is a pressure rod, and 6 is a barrel mold for molding the side surface of the optical element 4.

In order to mold the optical element 4 using this conventional mold for manufacturing optical elements, first the molding material 3 is placed on the lower mold 2, and the upper mold 1 is placed on top of it (FIG. 1). Next, it is heated in this state and set in a pressurizing device (not shown). Once heated to the temperature required for molding, the upper mold 1 is pressurized with a pressure rod 5, as shown in FIG. 2, to mold the optical element 4. After pressurizing the molding material 3 for a sufficient time to mold it into the optical element 4,
The pressurizing rod 5 is separated from the upper die 1 to remove the pressurizing force.
Thereafter, the optical element 4 is cooled while being in contact with the surfaces 1a and 2a of the upper mold 1 and the lower mold 2, respectively. In this way, the desired optical element 4 is obtained.

However, conventional optical element manufacturing has the following problems. That is, the process (first
), the contact points 1b, 2b between the molds 1, 2 and the molding material 3 are caused by the reaction between the mold and the material 3 for molding an optical element.
Then types 1 and 2 are violated, so the violated types 1,
The surface condition of No. 2 was transferred to the optical element 4, and a good optical surface could not be obtained. In addition, in conventional optical element manufacturing, the molding material 3 is held between a pair of molding molds as shown in FIG. Defects remained on the surface of the molded product.

[Objective] An object of the present invention is to provide an optical element manufacturing method for eliminating the above-mentioned drawbacks and obtaining an optical element having predetermined quality, precision, etc.

[Summary] The object of the present invention is to provide a method for manufacturing an optical element, which comprises: a. between an upper mold for molding a functional surface of the optical element and a lower mold for molding other functional surfaces of the optical element; b. heating at least the optical element molding material to a molding temperature while keeping the optical element molding material in a floating state; c. the upper mold and the lower mold. a pressurizing step of bringing the above floating state closer to each other and releasing the floating state and pressurizing the molding material heated to the molding temperature with the upper mold and the lower mold to mold the functional surface; d. after the pressurizing step, the upper molding material A cooling step of cooling the mold and the lower mold while keeping them in contact with the molded optical element molding material.

[Example] An example of the optical element manufacturing method according to the present invention will be described with reference to FIGS. 3 to 5.

Reference numeral 1' denotes an upper mold, which has a mirror-finished surface 1'a and a flange 7 for molding one functional surface of the optical element. 2' is a lower mold having a mirror-finished surface 2'a for molding the opposite functional surface of the optical element. 3 is a molding material, such as optical glass or optical transparent resin. The molding material 3 is located between the upper mold 1' and the lower mold 2' and is held without contacting them. 6' is the body type, and the molding material 3
It has steps 8 to keep it floating. The material of the body mold 6' is a heat-resistant member, and the body mold 6' and the lower mold 2' may be separate bodies or may be an integral body. Further, they may be made of different materials or may be made of the same material. For example, it is made of metal, ceramic, composite material, etc. 9
is a holder that holds the upper mold 1'. The holder 9 has a hole 1 that is slightly larger than the cylindrical diameter of the upper mold 1'.
0, and the upper mold 1' is suspended and held by the hole 10 and the collar 7 of the upper mold 1'. A pin 12 penetrates a hole 11 of the holder 9 in order to determine the position of the holder 9. Reference numeral 13 denotes a heat-resistant spring that lifts up the holder 9 and serves as a means for holding the upper die 1' away from the molding material 3. 14
1 is a clamp, and 15 is a clamp spring fixed to the lower part of the clamp 14. Clamp 14
moves in accordance with the upward and downward movements of the holder 9 and hangs on the holder 9. 16 is an auxiliary pressure rod,
Push down the holder 9 to urge the holder 9 to engage the clamp 14.

As shown in FIG. 3, the molding material 3 is held at the step 8 of the body mold 6' in a state separated from the surface 2'a of the lower mold 2'. The upper mold 1' is held apart from the molding material 3 by a holder 9 and a heat-resistant spring 13. Since the molding material 3 is placed at a predetermined location in a pressurizing device (not shown) without contacting the upper mold 1' and the lower mold 2', the material before molding may be damaged due to vibration etc. The surface will not be damaged. Even during heating to the molding temperature, the molding material 3 is not in contact with the upper mold 1' and the lower mold 2', and the molding material 3 is not in contact with the molding material 3 during molding.
The contact time with the upper mold 1' and the lower mold 2' can be shortened, and deterioration of the mold can be prevented.

As shown in FIG. 4, a molding material 3, an upper mold 1',
Once the lower mold 2' is heated to the temperature required for molding,
Pressure is applied to the upper die 1' by the pressure rod 5'. At this time, the holder 9 is pushed down with the auxiliary pressure rod 16 fixed to the pressure rod 5', and an air space 1 is created between the upper mold 1' and the holder 9.
Let 7 occur. Surface 1'a of upper mold 1', surface 2'a of lower mold 2' and body mold 6' under weight
As a result, the molding material 3 becomes an optical element 19. That is, the upper mold 1' press-deforms the molding material 3 until it comes into contact with the abutment surface 18 of the body mold 6'. Once the molding material 3 is transformed into the desired optical element 19, cooling is started. During cooling, in order to use the production mold efficiently, the pressure rod 5' and the auxiliary pressure rod 16 are removed from the mold, and the clamp 14 is hung on the holder 9.

As shown in FIG. 5, when the pressure rod 5' and the auxiliary pressure rod 16 are separated from the upper mold 1' and the holder 9, the holder 9 is caught by the clamp 14, preventing the holder 9 from rising. The position of the clamp 14 is adjusted in advance so that a gap 17 is created between the upper mold 1' and the holder 9, and the upper mold remains even after the pressing force from the pressure rod 5' and the auxiliary pressure rod 16 is removed. 1' is cooled by its own weight while in contact with the molded optical element 19, so that an optical surface with highly precise functions can be obtained. The manufacturing mold encloses and holds the optical element 19 in a cooling zone (not shown).
pass through.

In the above embodiments, a pair of upper and lower molds were described, but in the present invention, two or more pairs of upper and lower molds are arranged in a matrix, and holes corresponding to these arrangements are formed. It is also possible to operate simultaneously with one upper die holder.

[Effects] According to the present invention, the molding material is held floating between the upper mold and the lower mold until immediately before pressure molding, so there is little deterioration of the mold surface, and The material is resistant to scratches, and as a result, the resulting optical element and the upper and lower molds that are used repeatedly can be maintained with high precision.

In addition, after pressing and molding, in order to cool the molded optical element while keeping it in contact with the upper and lower molds, the molded optical element is passed through a heating zone, a press zone, a cooling zone, and a manufacturing mold in succession to improve precision. Optical elements with good quality can be molded with good mass productivity.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views of conventional molds for manufacturing optical elements. FIG. 3 is a state diagram in which a molding material is held in an optical element manufacturing mold in the method of the present invention;
FIG. 4 is a state diagram when the optical element manufacturing mold is being pressurized and molded, and FIG. 5 is a state diagram when the optical element manufacturing mold is being cooled. DESCRIPTION OF SYMBOLS 1... Upper mold, 2... Lower mold, 3... Molding material, 9... Holder, 15... Clamping spring, 16... Auxiliary pressure rod, 18... Abutment surface, 19... Optical element, 1'... Upper mold, 1'a...surface, 2'...lower die, 2'a...plane, 5'...pressure rod, 6'...body mold.

Claims (1)

[Scope of Claims] 1. A method for manufacturing an optical element, comprising: a. A mold for molding an optical element between an upper mold for molding a functional surface of the optical element and a lower mold for molding another functional surface of the optical element. b. keeping the optical element molding material in a floating state and heating at least the optical element molding material to a molding temperature; c. bringing the upper mold and the lower mold closer to each other. a pressing step of releasing the floating state and pressing the molding material heated to the molding temperature with the upper mold and the lower mold to mold the functional surface; d. after the pressing step, pressing the molding material with the upper mold and the lower mold; A method for manufacturing an optical element, comprising: a cooling step of cooling the molded optical element while keeping it in contact with the molded optical element molding material.