JP2007055008A - Demolding method of composite optical element and mold assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a demolding method of a composite optical element high in quality and productivity capable of easily demolding the composite optical element without applying large load to an optical element substrate. <P>SOLUTION: An up and down movable member 2b for changing the R of the surface 1a of a mold 1 and an actuator 2a for moving the up and down movable member 2b up and down are provided to the lower part of the mold 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for releasing a composite optical element and a mold apparatus for the composite optical element.

  In a method of molding a composite optical element, a technique for forming a non-adhesive layer made of a mold release agent is generally used as a method for facilitating mold release when the resin and the optical element substrate are integrally released from the mold. It is. For example, Japanese Patent Application Laid-Open No. 60-73816 proposes a method in which a release agent is applied to a mold by a dipping method, a spray method, a spin method, a brush coating method, or the like.

  Further, as a method different from the above-mentioned method, Japanese Patent Laid-Open No. 54-6006 discloses a method of giving a temperature difference between a resin and a mold material and releasing the mold by utilizing the difference in coefficient of thermal expansion, or Japanese Patent Laid-Open No. 60-76319. As disclosed in Japanese Laid-Open Patent Publication No. Hokukai, a method has been proposed in which an ultrasonic vibrator is brought into contact with a close contact body between a molded product and a mold to release the mold by applying ultrasonic vibration to the close contact body.

Further, in JP-A-06-270170, an elastic member made of a shape memory alloy is provided on the outer periphery of the optically effective diameter of the mold forming surface, the resin is brought into contact with the elastic member, the resin is cured, and then the elastic member There has been proposed a method in which the resin and the mold are separated by deforming.
Japanese Patent Laid-Open No. 60-73816 Japanese Patent Laid-Open No. 54-6006 JP 60-76319 A Japanese Patent Laid-Open No. 06-270170

  However, in the method of applying the release agent described in JP-A-60-73816 to the entire molding surface, it is difficult to control the thickness of the coating layer, and thus coating unevenness occurs. In addition, since the release agent is non-adhesive, the resin shrinks during curing, and the phenomenon that the resin partially peels, that is, the disadvantage that the upper face cannot be formed with high accuracy due to the occurrence of sink marks, There are problems in the work process, such as handling of the organic solvent for diluting the mold release agent and consideration of the working environment.

  Furthermore, if the mold release is repeated, the release agent gradually shifts to the resin and the non-adhesiveness of the surface is prevented from deterioration over time. Decreases. In order to avoid this, it is necessary to prepare many expensive molds.

  According to Japanese Patent Application Laid-Open No. 54-6006, since the deformation due to the difference in linear expansion between the mold and the resin due to heating at a predetermined temperature is used for mold release, all members are in a heat-deformed state compared to the initial shape, In order to return the mold to the initial shape, it has been confirmed by experiments that a mold shape regeneration time of 8 hours is required after returning to room temperature. Therefore, there is a problem that the time for applying a temperature change to the mold is long and the molding time period is long.

  Further, according to Japanese Patent Laid-Open No. 60-76319, an ultrasonic crack is applied to the adhesion body to induce an initial crack for releasing the molded product and the mold, but the time for which the vibration is continuously applied is long and stable. As a result, there is a problem that the molding time period becomes long. Further, according to Japanese Patent Laid-Open No. 06-270170, an elastic member made of a shape memory alloy is brought into contact with the resin on the concave lens substrate to cure the resin, and then the elastic member is deformed to separate the resin and the mold. To do. This presupposes that the shape of the elastic member is restored to the initial shape without the elastic member deforming beyond the critical stress.

  However, when the above configuration is adopted for a convex surface lens, the lens surface shape is in a direction opposite to the mold release direction. Therefore, a force exceeding the critical stress is applied to the elastic member at the time of mold release, so that the elastic member has an initial shape. May not play properly.

  In recent years, not only circular lens substrates but also microlenses, liquid crystal modules, etc. have been developed in which element substrates have been made thinner, and it is even more likely to give a large mechanical load to the outer diameter of the substrate when released. It has become difficult.

  The present invention has been made in consideration of the above problems, and its purpose is not limited by the surface shape of the element substrate, and is excellent in quality and productivity that can be easily released without applying a heavy load to the element substrate. Another object of the present invention is to provide a mold release method and a mold apparatus for a composite optical element.

  In the present invention, an energy curable resin is placed on the surface of a glass substrate, and the resin is cured by irradiating energy in a state where a mold forming surface having a desired shape inverted is pressure-bonded. In a mold release method for a composite optical element that is released from a mold, an actuator capable of moving up and down is built in the mold, and a surface shape portion is formed by pushing up or down the outer peripheral surface of the mold with the actuator. This is a method in which R is changed and the resin and the mold are peeled off.

[Action]
The operation of the present invention will be described below. In the prior art, when an external force F for peeling the resin 3 from the mold 2 is applied to the outer peripheral portion of the glass substrate 4 as shown in FIG. 2, the force is distributed in an arc shape on the contact surface between the resin and the mold, and the resin and the mold Mold peeling does not occur at all. Therefore, if the external force F is increased to peel the substrate, the substrate 4 is damaged, and the mold cannot be released.

  On the other hand, in the present invention, as shown in FIG. 1, by providing a movable member 2b that can move up and down inside the mold 1 and an actuator 2a for moving, the R of the mold surface 1a can be changed. By changing R of the mold surface 1a, a force Fc that promotes peeling is generated between the resin 3 and the mold surface 1a as shown in FIG. Conversely, as shown in FIG. 4, it is also possible to generate a force Fd that increases the internal stress of the resin.

  As is apparent from the above description, according to the present invention, there is no occurrence of unevenness in the appearance of the molding surface due to unevenness in the mold release process, and it is not necessary to apply a long-term external load such as temperature change and ultrasonic waves for each molding. Therefore, the molding time is shortened and the cost of the molded product can be reduced.

Example 1
5 to 8 show the present embodiment, FIG. 5 is a schematic view of the apparatus, and FIGS. 6 to 8 are schematic views showing the molding process. The mold 1 is held on a base 6 so as to be movable up and down, and an ejector 5 for holding a glass substrate and generating a release force F is attached to the outer periphery of the mold 1.

  A substrate 4 placed on the same axis is disposed above the mold 1. A urethane acrylate ultraviolet curable resin 3 is interposed between the mold 1 and the substrate 4, and the mold 1, the substrate 4 and the resin 3 are in close contact with each other. An ejector 5 for holding the substrate 4 is provided on the outer peripheral portion of the substrate 4.

  Next, the molding process will be described with reference to FIGS. First, an appropriate amount of uncured resin is discharged onto the upper surface of the substrate 4 formed of the optical glass BK. In order to improve the adhesion to the resin 3 on the molding surface of the substrate 1 in advance, an aluminum oxide thin film is coated to a thickness of about 300 nm by a vapor deposition method, and further a silane coupling agent is dip coated and dried at 80 ° C. for 30 minutes. Process. The coupling agent used here is 1 to 2 wt% of a silane coupling agent A-174 (trade name; Nippon Unica Co., Ltd.) in a solvent solution in which acetic acid is adjusted to Ph5 in a water: ethanol 1: 9 solution. Stations diluted at a rate of Next, the substrate 4 is inverted and placed on the ejector 5. Further, the mold 1 is raised and brought closer to the substrate 4 to spread the resin 3, and stops at a position where the resin 3 has a desired thickness.

In this state, the resin 3 is cured by irradiating ultraviolet rays from above the substrate 4. As a result, an adhesion body in which the mold 1, the substrate 4 and the resin 3 are in close contact with each other is formed. Next, the movable member 2b is raised by the actuator 2a of FIG. 1 installed inside the mold 1 to change the R of the mold surface 1a, and the force Fd in FIG. As a result, an internal stress is generated in the resin 3, and when the ejector 5 is raised and brought into contact with the outer peripheral portion of the substrate 4 to release the mold, the internal stress of the resin 3 serves to assist the mold release, and easily and instantly The composite optical element that is an adhesive body of the substrate 4 and the resin 3 is released from the mold 1. (Fig. 8)
According to the present embodiment, continuous release can be easily performed without subjecting the surface 1a of the mold 1 to the release treatment.

  In this embodiment, when the movable member 2b is moved, the actuator 2a uses a piezo element to cause an R change of Δh = 0.005 to 0.01 mm with respect to a radius of 30 mm. May be performed manually using an inexpensive micro head or the like instead of an expensive piezo element actuator.

(Example 2)
In this embodiment, the movable member 1a in the first embodiment described above is arranged so as to be hooked on the lower part of the outer peripheral portion, and a force Fc that promotes the separation of the resin 3 and the mold 1 is generated as shown in FIG. It is the structure made to let it be. The configuration is the same as that of the first embodiment, and a description thereof will be omitted.

  The present embodiment has the same operation as that of the first embodiment, and the description of the operation is omitted.

  According to the present invention, the same effect as in the first embodiment can be obtained, and the force Fc is generated in the direction of directly promoting the peeling, so that the mold release is easier. In particular, it is possible to release the composite optical element formed with a fine shape that is not spherical or aspherical, such as a diffractive optical element, while maintaining the shape.

(Comparative Example 1)
As a comparative example of the present invention, a mold, a substrate, and a resin adhesion body similar to the present invention are formed using a mold in which the outer periphery of the optical effective diameter of the mold is mirror-finished in the same manner as the optical effective surface, When the mold was released using the same ejector as in the present invention, the adhesion between the mold and the resin was large, and the substrate was damaged by the mold release.

(Comparative Example 2)
As a comparative example of the present invention, a mold, a substrate and a resin adhesion body similar to the present invention are formed using a mold in which a mold release agent treatment is applied to the outer periphery of the optical effective diameter of the mold and the optically effective surface. However, when the mold was released using the same ejector as that of the present invention, it was not possible to release the mold easily by several tens, and the substrate was damaged as in Comparative Example 1, so that the mold could not be released.

Mold internal view of the present invention Explanatory drawing showing a conventional example Explanatory drawing which shows Example 2. Explanatory drawing of the molding process of Example 1 Explanatory drawing of the molding process of Example 1 Explanatory drawing of the molding process of Example 1 Explanatory drawing of the molding process of Example 1 Explanatory drawing of the molding process of Example 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold structure part 1a Mold surface part 2a Actuator 2b Vertical movable member 3 Resin 4 Glass substrate 5 Ejector 6 Mold base

Claims (3)

  An energy curable resin is placed on the surface of the optical element substrate, and the resin is cured by irradiating energy in a state where a mold forming surface having a desired shape reversed is pressed, and the cured resin is removed from the mold. In the mold release method of the composite optical element to be released, a movable member is disposed at the lower part of the outer periphery of the mold molding surface, and after the resin is cured, the lower peripheral part of the mold molding surface is pushed onto the molding surface. A method for releasing a composite optical element, wherein the resin and the mold are separated by changing R.   An energy curable resin is placed on the surface of the optical element substrate, and the resin is cured by irradiating energy in a state where a mold forming surface having a desired shape reversed is pressed, and the cured resin is removed from the mold. In a mold release method for a composite optical element to be released, the movable portion according to claim 1 is moved in advance and the molding surface is deformed to a desired R, then the resin is cured, and after the cure, the movable member is moved to move the mold. A mold release method for a composite optical element, wherein peeling of a resin and a mold is advanced by changing R of a molding surface.   3. The method of releasing a composite optical element according to claim 1, wherein the mold molding surface has elasticity and is easily deformed by being pushed from below, and as a result, R of the molding surface is changed.

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