JPH11130448A - Optical element and its production and mold for forming optical element used for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element efficiently and inexpensively joined with >=2 kinds of optical elements with high accuracy by heating and pressurizing the first optical element blank by a pair of first and second molds and master mold, removing the second mold, placing a second optical element blank and a third mold and molding the optical element by heating and pressurizing and a process for producing the same as well as dies for forming the optical element using the same. SOLUTION: The first optical element 9 exists on the first mold 1 having the optical surface shape of the first optical element 9 and the second optical element blank 6 is placed thereon. Further, the third mold 5 having the optical surface shape of the second optical element is placed thereon. The first optical element 9 is formed and thereafter the second optical element blank 6 having a lower m.p. is formed between the first optical element 9 and the third mold, by which the joined optical element is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an optical element used for an optical system such as a photographing lens and an optical pickup, a method for manufacturing the same, and a mold for molding an optical element used for the same.

[0002]

2. Description of the Related Art Conventionally, an optical element in which two or more kinds of lenses or prisms are joined is manufactured by joining an optical element which has been finished in advance by grinding, polishing or press molding with an adhesive represented by an ultraviolet curing type. Have been. However, this method requires a step of manufacturing each optical element, a step of positioning and arranging the two kinds of optical elements with high precision, and a step of uniformly applying and curing an adhesive evenly without bubbles. This is an obstacle to improving accuracy and production efficiency.

On the other hand, in order to eliminate the positioning step and the bonding step, a raw material is arranged between a first optical element and a molding die, and a second optical element is molded by heating and pressing. A manufacturing method using a step of integrating this into the first optical element has been proposed in Japanese Patent Application Laid-Open No. 60-67118. This method uses an optical element that has already been processed, places it on a holder, and places a second material and a molding die on it sequentially, and heats and presses it to produce a synthetic optical element. Is what you do.

[0004]

In the above conventional example, the first
This optical element is a manufacturing method in which a pre-processed optical element is brought in the same manner as the bonding with an adhesive, and the step of bonding to the second optical element is omitted. In this case, after the first optical element is processed, it is gripped and transported by some means, and contaminants from the gripping / transfer jig or in the air adhere to the optical element surface, and the second optical element is processed. Defective products are liable to occur due to dirt and insufficient adhesive force on the bonding surface with the optical element. Further, when placing the first optical element on the holder jig, it is necessary to insert and arrange the first optical element while taking care not to cause eccentricity and to prevent chipping on the holder. For this reason, a significant improvement in production efficiency cannot be achieved. Also, in order to insert the already processed optical element into the holder, a gap must be created by making the inner diameter of the holder larger than the outer diameter of the optical element, resulting in eccentricity between the first optical element and the holder. In this case, the first optical element and the second optical element become eccentric, which causes poor optical performance.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an optical element in which two or more types of optical elements are joined with high accuracy, efficiently, and inexpensively, a method of manufacturing the same, and an optical element molding die used therefor. Aim.

[0006]

In order to achieve the above object, an optical element according to the present invention comprises a first and a second pair of molds and a barrel mold, which heat and pressurize a first optical element material to form a first optical element. An optical element is formed, the second mold is removed, the second optical element material and the third mold are placed, and the structure is formed by heating and pressing.

In the optical element, holes having diameters corresponding to the first mold, the second mold and the third mold are formed in the body mold, and the first mold and the first optical element are formed. It is preferable to use an optical element molding die capable of molding the second optical element by mounting the second optical element material and the third die while keeping the body in the mold.

In the above optical element, the sum of the lengths of the third mold and the second optical element in the central axis direction is equal to or longer than the length of the second mold in the central axis direction. Is preferred.

Next, the method for manufacturing an optical element according to the present invention comprises the following steps.
The first optical element material is heated and pressurized with a pair of second mold and body mold to form a first optical element, the second mold is removed, and the second optical element material and the third mold are removed. It has a configuration in which it is placed, heated and pressed to form.

In the above method, holes having diameters corresponding to the first mold, the second mold and the third mold are formed in the body mold, and the first mold and the first optical element are formed. It is preferable to use an optical element molding die capable of molding the second optical element by mounting the second optical element material and the third die while being fitted to the body mold.

In the above method, the sum of the lengths of the third mold and the second optical element in the center axis direction may be equal to or longer than the length of the second mold in the center axis direction. preferable.

Next, in the optical element molding die of the present invention, the first optical element material is heated and pressed by the first and second pair of molds and the body mold to form the first optical element. In the optical element molding die in which the mold is removed, the second optical element material and the third mold are placed, and the body is molded by heating and pressing, the first mold, the second mold and the third mold are added to the body mold. A hole having a diameter corresponding to each of the molds is formed, and the second optical element material and the third mold are placed while the first mold and the first optical element are still fitted in the body mold. A mold capable of molding the second optical element.

In the mold, it is preferable that the sum of the lengths of the third mold and the second optical element in the center axis direction is equal to or longer than the length of the second mold in the center axis direction. .
In the present invention, the first optical element material is heated and pressed by the first and second pair of molds and the body mold to form the first optical element,
The optical element is manufactured by removing the second mold, placing the second optical element material and the third mold, and applying heat and pressure to mold the optical element. Then, holes having diameters corresponding to the first mold, the second mold, and the third mold are formed in the body mold, and the first mold and the first optical element are kept fitted in the body mold. In this state, an optical element molding die having a configuration in which the second optical element material and the third mold can be placed to mold the second optical element is used. Furthermore,
For the length of the second mold in the direction of the central axis, the third mold and the second mold
An optical element molding die is used in which the sum of the lengths of the optical elements in the central axis direction is equal or longer.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
This will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a diagram showing a method for manufacturing an optical element of the present invention. A first mold 1 having an optical surface shape of a first optical element 9 (for example, boric glass VC79 (manufactured by Sumita Optical Glass Co., Ltd.) or the like) (for example, a base material of a cemented carbide mainly composed of WC) The first optical element 9 is provided on a mold on which a platinum alloy is formed on the molding surface), and the second optical element material 6 (for example, lead glass SF8) is placed thereon. A third mold 5 having the optical surface shape of the element (for example, the same mold as the first mold is used) is mounted. This represents an intermediate step in a series of manufacturing steps of one embodiment of the present invention, in which the first optical element is molded,
The second optical element material having a lower melting point is combined with the first optical element and the third optical element.
Molding is performed between the molds to obtain a bonded optical element. The deformation point temperature, which is one of the deformable temperatures of the first optical element (borate glass VC79), is 553 ° C., and the deformation point temperature of the second optical element material (lead glass SF8) is 459 ° C. Therefore, the temperature difference is 94 ° C.

Next, the manufacturing method of the present invention will be described step by step. First, as shown in FIG.
The spherical first optical element material 3 is placed on the first mold 1, and the second mold 2 is inserted into the body mold 4 from above. In this state, the optical element material is heated to a deformable temperature and the mold is pressurized.
The first optical element 9 shown in FIG. Then, as shown in FIG. 4, the second mold 2 is pulled out by the mold transport jig 10a, the second optical element material 6 held by the glass material holder 11 is placed on the first optical element 9, and the mold transport jig is further provided. Third by 10b
The mold 5 is inserted and placed. Since the second optical element material and the third mold are successively placed without touching the optical element after the molding of the first optical element, the clean surface of the first optical element immediately after molding may be stained. Absent. In addition, the first mold, the body mold, and the first optical element are fitted without being disassembled, and the first optical element has the same positional relationship as the shape transferred from the first mold forming surface and the inner surface of the body mold. Since it is kept, there is no shape error such as eccentricity. Inevitably, an accident such as chipping when the optical element is inserted into the mold, which is a problem of the conventional example, does not occur.

Also, in this embodiment, a neck portion to be inserted into the first, second and third mold dies as holes having diameters corresponding to the first, second and third dies, respectively. Since the outer diameters are all the same, a hole having an inner diameter is formed in the body mold by adding a clearance of several microns required for insertion to the outer diameter of the mold. Therefore, it is possible to form the second optical element by placing the second optical element material and the third mold while keeping the first mold and the first optical element in the body mold. Become the second
The above effects can be obtained as a minimum disassembling step of exchanging the mold and the third mold.

In this state, the material of the second optical element is heated to a temperature at which the material can be deformed, and the mold is pressed. As shown in FIG.
The optical element is molded, and at the same time, the joined optical element 8 is obtained. This is cooled, and the third mold, the first mold, and the body mold are disassembled and taken out to obtain the bonded optical element 8 shown in FIG.

As described above, the first optical element is formed by merely exchanging the second mold and the third mold without disassembling the first mold, the body mold, and the first optical element. The accuracy of the eccentric position such as the inclination and axis deviation of the second optical element and the second optical element can be obtained according to only the accuracy of the shape of the molding die, and a joint optical element equivalent to the high precision of a normal single molded optical element can be obtained.

Further, by making the sum of the lengths of the third mold and the second optical element in the center axis direction equal to or longer than the length of the second mold in the center axis direction, The first optical element and the second optical element can be molded with the same body mold and first mold.

Further, when the second optical element is formed, the first optical element is held not by a holder having an approximate shape but by a molding die having a predetermined optical function surface. Therefore, the second optical element is formed. Sometimes, the shape of the first optical element does not change.

In this embodiment, the total length of the second die in the central axis direction is equal to the total length of the third die and the second optical element in the central axis direction. However, the present invention is not limited to this. The length of the mold does not affect the length of the optical element to be molded.
It is effective if the sum of the lengths in the central axis direction of the second optical element and the length of the second optical element is equal to or longer than that of the second optical element. The third type is shorter than the second type, so that the total length is
The present invention is effective even if the sum of the mold and the second optical element is shorter.

(Embodiment 2) In this embodiment, the inner diameter of the body mold is the same over the entire length, and the first mold, the second mold and the third mold are used.
Although the diameter of the neck inserted into the mold of the mold has the same dimensional configuration as the inside diameter of the mold, the present invention is not limited to this embodiment. For example, as shown in FIG. 7, the outer diameter of the second die 12 and the third die 13 and the outer diameter of the first die 11 are different, and the inner diameter of the body die 14 is a stepped hole correspondingly. Obviously, the same effect can be obtained. The present invention relates to the first
Holes having a diameter corresponding to each of the first mold, the second mold and the third mold are formed, and the second optical system is kept in a state where the first mold and the first optical element are still fitted in the body mold. It is effective if the element material and the third mold are placed and the second optical element can be molded.

In this embodiment, the material of the optical element has a spherical shape and a disk shape. However, the present invention is not limited to such a shape, but various shapes such as a disk and a free-form surface can be used. It is effective to use. Also, the mold is not limited to the shape shown in the present embodiment, and it is also effective to use a mold having another shape such as a brimless type, a double trunk type.

Further, as shown in the above embodiment, the first mold is not limited to the lower mold, and the second mold is not limited to the upper mold. After the first optical element is molded, it is inserted into the body mold. The original mold is the first mold, and the mold to be removed is the second mold.

[0025]

As described above, according to the present invention,
An optical element in which the first optical element and the second optical element are molded and joined in a series of steps can be obtained. The conventional alignment and bonding processes are not required, and high-precision and efficient production has become possible. In addition, the above-described mold configuration allows the first mold and the body mold to be used in common, and can be a process in which only the second mold and the third mold are exchanged, so that high precision and improvement in production efficiency can be realized.

[Brief description of the drawings]

FIG. 1 shows a second example of a manufacturing process according to an embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view before optical element molding.

FIG. 2 is a view before molding a first optical element.

FIG. 3 is a view after molding a first optical element.

FIG. 4 is a view showing a process of exchanging a mold and placing an optical element material in the same manner.

FIG. 5 is a view after molding a second optical element.

FIG. 6 is a perspective view of the same optical element.

FIG. 7 is a schematic diagram of another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1,11 First type 2,12 Second type 3 First optical element material 4,14 Body type 5 Third type 6 Second optical element material 7,16 Second optical element 8,17 Joint optical element 9,15 Reference Signs List 1 optical element 10a, 10b type transfer jig 11 glass holder 13 third type

Claims (8)

[Claims] A first pair of first and second molds and a body mold form a first mold.
An optical element formed by heating and pressurizing the optical element material to form a first optical element, removing the second mold, placing the second optical element material and the third mold, and heating and pressurizing. 2. The body mold has holes of diameters corresponding to the first mold, the second mold, and the third mold, respectively, and the first mold and the first optical element are formed in the body mold. 2. The optical element according to claim 1, wherein an optical element molding die having a configuration in which the second optical element material and the third mold can be placed in a state of being fitted to form the second optical element is used. 3. With respect to the length of the second mold in the direction of the central axis,
3. The optical element according to claim 1, wherein the sum of the lengths of the third mold and the second optical element in the central axis direction is equal to or longer than the third mold. 4. A first pair of first and second molds and a body mold,
The first optical element is molded by heating and pressing the optical element material of (1), the second mold is removed, the second optical element material and the third mold are placed, and the optical element is molded by heating and pressing. Production method. 5. The body mold has holes of diameters corresponding to the first mold, the second mold, and the third mold, respectively, and the first mold and the first optical element are formed in the body mold. 5. The method for manufacturing an optical element according to claim 4, wherein the second optical element material and the third mold are placed in a state where they are fitted, and an optical element molding die capable of molding the second optical element is used. . 6. The length of the second mold in the direction of the central axis,
The method for manufacturing an optical element according to claim 4, wherein the sum of the lengths of the third mold and the second optical element in the central axis direction is equal to or longer than each other. 7. A first pair of first and second molds and a body mold,
Forming the first optical element by heating and pressing the optical element material of (1), removing the second mold, placing the second optical element material and the third mold, and forming the optical element by heating and pressing In the mold, holes having diameters corresponding to the first mold, the second mold, and the third mold are formed in the body mold, and the first mold and the first mold are formed.
Wherein the second optical element material and the third mold are placed in a state in which the optical element of (1) is still fitted in the body mold, and the second optical element is molded. . 8. With respect to the length of the second mold in the direction of the central axis,
The mold for molding an optical element according to claim 7, wherein the sum of the lengths of the third mold and the second optical element in the central axis direction is equal or longer.