JP2005186513A - Forming having minute shape, optical element, forming method, and forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a forming method for a formed article having a minute structure with a high aspect ratio or a small angle R simply at low costs, an apparatus for the method, the formed article, and an optical element. <P>SOLUTION: By moving movable dies 3 and 3' at a speed of 10 mm/s or above toward a resin material, impact energy is given to the resin material, so that a minute shape having a high aspect ratio, which has been unable to form by a conventional technique, can precisely be transferred/formed. Since the heated movable dies 3 and 3' are brought into contact with the resin material for a short time, even when the surface of the minute shape is melted/deformed by heat transmitted from the dies, an inside part is kept to be rigid. By quick releasing, the formed minute shape is maintained to increase a successful transfer area as compared with a conventional case. Moreover, as a secondary effect of increasing the moving speed, a forming time can be curtailed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a molded article having a fine shape, an optical element, a molding method, and a molding apparatus, and more particularly to a molded article having a fine shape having a high aspect ratio, an optical element, a molding method, and a molding apparatus.

  In recent years, optical elements such as objective lenses with extremely high accuracy are used in the field of optical pickup devices that are rapidly developing. When a material such as plastic or glass is molded into such an optical element using a mold, a product having a uniform shape can be quickly produced. It can be said that it is suitable for mass production.

  Furthermore, recent optical pickup devices use a light beam from a semiconductor laser with a shorter wavelength to record high-density information on a recording medium such as an AOD (Advanced Optical Disc) or BD (Blueray Disc) and / or What can be reproduced has been developed, and in order to improve aberration characteristics of the optical system, a diffractive structure which is a fine structure is provided on the optical surface. Further, even in an optical pickup device capable of recording and / or reproducing such high-density information, it is necessary to ensure the recording and / or reproducing of information even with respect to CDs and DVDs that have conventionally been supplied in large quantities. For this reason, a diffractive structure having wavelength selectivity is also provided.

  Here, although the diffraction structure depends on the wavelength of the light source to be used, for example, since the step is a ring zone structure having a minimum level of about 2 μm, in ordinary injection molding, the molten resin is simply injected into the mold. There is a problem that the material is difficult to enter deep in the depth of the formed fine structure, so that the fine structure is not accurately transferred. If the designed diffractive structure is not formed due to transfer defects (sagging of the material), the diffraction characteristics deteriorate, and there is a possibility that a write error or the like occurs in the optical pickup device using such an optical element. For this reason, various ideas such as selection of materials and adjustment of the temperature and pressure of the molten resin have been made. However, it is difficult to completely eliminate sagging with conventional methods.

On the other hand, Patent Document 1 below discloses a method of molding an optical element having a fine pattern on the surface by pressing a glass material in a heat-softened state.
Japanese Patent Laid-Open No. 2002-220241

  However, the technique described in Patent Document 1 is limited to molding a fine shape having a width of about 100 to 50 μm and a height of about 20 to 10 μm with an aspect ratio of about 0.2 on the surface of the glass material. . This is because the elastic modulus of inorganic glass at room temperature is as high as about 70 GPa, so even if a mold heated with a very large force of 3000 N is pressed on its surface, the glass material does not flow smoothly into the back of the microstructure, As a result, only a fine shape having an aspect ratio of about 0.2 could be formed. Therefore, for example, a molded product having a fine shape with an aspect ratio of 1 or more may exist as a prototype, but it does not yet exist as an industrial product with a uniform shape.

  In addition, in recent years, an attempt has been made to add a new optical function to an optical element by applying a fine structure smaller than several times the wavelength of a light source to be used to the optical surface. For example, the normal focusing function due to refraction of a molded lens and the positive dispersion that occurs as a side effect at that time are utilized by utilizing the large negative dispersion due to diffraction obtained by forming a diffraction groove on the surface of the aspheric optical surface. Of these, it has been put to practical use with a pickup objective lens for an optical disk compatible with DVD / CD to add an achromatic function, which is essentially impossible with refraction alone, to a single optical element. This utilizes the diffractive action of a diffraction groove having a size several tens of times the wavelength of light transmitted through the optical element, and the region that handles the diffractive action by a structure sufficiently larger than the wavelength is called a scalar region. It is.

  On the other hand, it has been found that the light reflection suppressing function can be exhibited by forming the conical projections densely on the surface of the optical surface at a minute interval of a fraction of the wavelength of the light transmitted through the optical element. Yes. That is, the refractive index change at the interface with the air when the light wave enters the optical element is not instantaneously changed from 1 to the medium refractive index as in the conventional optical element, but is arranged at a fine interval. By changing the shape of the protrusions gradually, the reflection of light can be suppressed. The optical surface on which such protrusions are formed has a fine structure called a so-called “eyes”, and individual structures can no longer be obtained by arranging structures finer than the wavelength of light with a period shorter than the wavelength. It works as an average refractive index for light waves without being diffracted. Such a region is generally called an equivalent refractive index region. Regarding such an equivalent refractive index region, see, for example, IEICE Transactions C Vol. J83-C No. 3pp. 173-181, described in March 2000.

  According to the microstructure of the equivalent refractive index region, it is possible to obtain a large antireflection effect while reducing the angle dependency and wavelength dependency of the antireflection effect as compared with the conventional antireflection coating, but according to plastic molding or the like, Since the optical surface and fine structure can be created at the same time, the lens function and the antireflection function can be obtained at the same time, and there is also a great merit in production such that post-processing such as antireflection coating treatment after molding is unnecessary as in the past. It is considered and is attracting attention. Furthermore, if such a fine structure of the equivalent refractive index region is arranged so as to have directionality with respect to the optical surface, it is possible to give the optical surface strong optical anisotropy. Thus, the birefringent optical element produced can be obtained by molding, and a new optical function can be added in combination with a refractive or reflective optical element. The optical anisotropy in this case is called structural birefringence.

  Between the above-described scalar region and equivalent refractive index region, there is a resonance region in which the diffraction efficiency changes rapidly due to a slight difference in incident conditions. For example, when the groove width of the diffraction ring zone is narrowed, a phenomenon (anomaly) occurs in which the diffraction efficiency rapidly decreases and increases by several times the wavelength. By utilizing the characteristics of this region, a waveguide mode resonance grating filter that reflects only a specific wavelength can be realized with a fine structure, and the same effect as a normal interference filter can be realized with less angular dependence.

  By the way, when an optical element is formed using a scalar region, an equivalent refractive index region, a resonance region, or the like, it is necessary to form fine protrusions (or depressions) on the optical surface. In order to mass-produce optical elements having such fine protrusions (or dents), it can be said that it is generally suitable to perform molding using a resin as a raw material. The problem is how to form an optical surface transfer surface having a depression (or protrusion) corresponding to the depression.

  That is, for the projections (or depressions) in the equivalent refractive region and the resonance region as described above, the projections (or depressions) must be formed on the optical surface of the optical element at intervals of several tens to several hundreds of nanometers. In conventional injection molding, the resin does not reach the depth of the fine shape of the mold corresponding to it, and it is extremely difficult to accurately transfer the fine shape.

  The present invention has been made in view of such problems of the prior art, and more easily and at low cost, a molding method and a molding apparatus capable of molding a molded product having a fine structure with a high aspect ratio or a small angle R, and An object of the present invention is to provide a molded product and an optical element.

  The molded product according to the first aspect of the present invention is a molded product formed by pressing a mold, has an elastic modulus at normal temperature of 1 to 4 (GPa), and a thickness after molding of 0.1 mm to 20 mm. The aspect ratio of the fine shape formed on the molding surface is 1 or more, and the fine shape has a shearing surface.

  In view of the above-mentioned problems, the present inventors have devised a method capable of forming a molded product having a fine shape from a completely different viewpoint as a result of intensive studies. That is, in the case of a resin material having an elastic modulus of 1 to 4 (GPa) at room temperature, when a mold having a fine shape is heated and pressed against the mold surface, the pressed surface is melted to a fine shape. As a result, it was found that even if the aspect ratio is 1 or more, a molded product in which the fine shape of the mold is accurately transferred can be obtained. In such a case, as described in Patent Document 1, a pressing force of 3000 N is unnecessary, it is sufficient to improve the conventional injection molding machine, the manufacturing equipment is reduced in cost, and a large amount of molding is performed in a short time. It becomes possible to manufacture a thing.

  However, through further experiments by the present inventors, it has been found that the defect rate increases when an attempt is made to form a fine shape with a very small line width and a high aspect ratio using the fine shape transfer method described above. . For example, if a fine shape with a line width of 100 nm and an aspect ratio exceeding 1 is formed, the releasability when the mold is peeled off from the molded product is poor, and the fine shape is destroyed by the mold release. There are things that end up.

  Therefore, the present inventors have conducted further intensive studies to derive a technique that is effective for reducing the defect rate particularly when a fine shape with a high aspect ratio is formed. This is based on an extremely innovative idea that combines mechanical processing with molding processing of a resin material.

  Here, the transfer method that has been found to increase the defect rate is that the heated mold is brought close to the resin material at a very slow speed of, for example, 0.05 mm / s, and the heat of the mold is sufficiently applied to the resin material. A fine shape is formed while being melted and deformed. However, in this technique, the present inventors have a problem that the fine shape melts and deforms due to the temperature of the mold being transferred to the resin material, the strength decreases, and the mold cannot be withstood at the time of mold release and breaks. I found it. On the other hand, after transferring the fine shape, the mold and the resin material can be cooled as they are, and then the mold is released after the fine shape is solidified. Since the thermal shrinkage rate of the resin material is different from that of the resin material, there is a problem that the fine shape is damaged during cooling. Further, even when the heated mold is pressed against the resin material for a long time, there is a problem that the resin material is gradually deformed by creep.

Therefore, the present inventors changed the way of thinking and examined whether a fine shape could be formed by applying impact energy to the resin material. Impact energy E is the type of mass m, when the moving speed to v, from being represented by E = mv ^2/2, by increasing the moving velocity v, a stunner energy E to the resin material It was decided. According to the results of experiments by the present inventors, when the mold is brought close to the resin material at a moving speed of 10 mm / s or more, impact energy is imparted to the resin material, thereby making it impossible to form with a conventional technique. A fine shape with an aspect ratio could be accurately transferred and formed. In addition, since the time for which the heated mold is in contact with the resin material is short, even if the surface of the fine shape is melted and deformed by heat transfer from the mold, the inner part remains rigid, so that the mold can be released quickly. By doing so, the formed fine shape was maintained, and the transfer success area was increased as compared with the conventional case. Furthermore, as a secondary effect of increasing the moving speed, the molding process time has been shortened. A sheared surface formed by applying impact energy was confirmed in the formed fine shape. The present invention is particularly effective when a fine shape having a line width of 500 nm or less is formed.

  In order to increase the impact energy E, it is conceivable to increase the mass m of the mold. However, since the apparatus may be increased in size, it is more convenient to increase the moving speed v as in the present invention. It can be said that there are many things.

  Incidentally, materials having an elastic modulus of 1 to 4 (GPa) at room temperature include, for example, PMMA (elastic modulus of 1.5 to 3.3 GPa), polycarbonate (elastic modulus of 3.1 GPa), polyolefin (elastic modulus of 2). It is preferable to contain, as a composition component, a resin having an elastic modulus in the range of 1 to 4 such as .5 to 3.1 GPa). Here, room temperature means 25 ° C. These resins preferably have a glass transition point of 50 to 160 ° C. The elastic modulus can be obtained according to JIS-K7161, 7162, and the like. The glass transition temperature can be determined according to JIS R3102-3: 2001.

  As shown in FIGS. 1A and 1B, the “aspect ratio” is represented by B / A, where A is the width of the concave or convex portion of the microstructure and B is the depth or height. Value. “Fine shape” means a shape having a value of A of 10 μm or less. The thickness after molding refers to the thickness of the molded product in the direction in which the mold is pressed, and is, for example, the value of T shown in FIG. The thickness after this molding is 0.1 to 20 mm, preferably 1 to 5 mm.

  Furthermore, it is preferable that the fine shape causes structural birefringence.

  Furthermore, it is preferable that the fine shape has a periodic structure with a size equal to or smaller than the wavelength of light and has an antireflection function.

  Further, the molded product is preferably an optical element because good optical characteristics can be obtained, but it can also be applied to an inkjet printer head or the like.

  The optical element of the second aspect of the present invention is an optical element whose optical surface is molded by pressing a mold, and has an elastic modulus at normal temperature of 1 to 4 (GPa) and a thickness after molding of 0.1 mm or more. 20 mm or less, the radial pitch in the annular diffraction structure formed on the optical surface is 10 μm or less, the radius of curvature of the corner in the cross section in the optical axis direction of the diffraction structure is less than 1 μm, and the diffraction The structure is characterized by having a shear surface.

  In conventional injection molding, since it is difficult for the resin to penetrate deep into the microstructure of the mold corresponding to the diffractive structure, the resulting diffractive structure of the optical element has a sagging corner in the cross section in the optical axis direction and its curvature. The radius greatly exceeds 1 μm, and the light transmittance may be deteriorated. On the other hand, in the optical element of the present invention, a high-aspect-ratio diffractive structure can be precisely transferred by the above-described method, the radius of curvature of the corner in the cross section in the optical axis direction of the diffractive structure is less than 1 μm, and higher light transmittance. Can be obtained. Such a molded product or optical element can be obtained by the following molding method or molding apparatus.

  The molding method according to the third aspect of the present invention includes a step of setting a temperature of a mold having a fine shape higher than a glass transition temperature of a material having an elastic modulus at room temperature of 1 to 4 (GPa), By pressing toward the material at a speed of 10 mm / s or more, there are a step of transferring the fine shape to the material and a step of releasing the mold having the fine shape from the resin material. It is possible to easily mold a molded article having a fine shape with a specific ratio or an optical element having a diffractive structure with a radius of curvature of a corner in an optical axis direction cross section of less than 1 μm.

  Furthermore, before pressing the mold toward the material, it is preferable to have a step of injecting the material and a step of cooling the material between the mold having the fine shape, and the mold facing the mold.

  A molding apparatus according to a fourth aspect of the present invention includes a movable mold having a fine shape, a fixed mold that shields the movable mold so as to surround the fine shape, a heater that heats the movable mold, the movable mold, and the fixed mold. A drive unit that relatively moves the mold, and in a space closed by the movable mold and the fixed mold, a material having an elastic modulus of 1 to 4 (GPa) at room temperature is disposed, and at least the In a state where the inside of the material is solidified, the movable mold is heated by the heater, and the moving part relatively moves the movable mold toward the material at a speed of 10 mm / s or more, thereby making the movable mold fine. Since the shape is transferred, it is possible to easily mold a molded product having a fine shape with a high aspect ratio or an optical element having a diffractive structure with a radius of curvature of a corner portion in an optical axis direction cross section of less than 1 μm.

  In addition, when molding using the molding apparatus of the present invention, a mother shape other than a fine shape is molded in advance by injection molding or the like, and then heated above the glass transition point of the material with the inside of the material solidified. By pressing the movable mold against the material, the fine shape is transferred to the material while maintaining the mother shape. Therefore, the material is preferably injected into a space closed by the movable mold and the fixed mold. However, the mold for forming the mother shape and the movable mold for forming the fine shape may be separated, and in such a case, the material can be cooled at the time of mold replacement.

  According to the present invention, it is possible to provide a molding method and molding apparatus, a molding product, and an optical element that can mold a molding having a microstructure with a high aspect ratio or a small angle R more easily and at low cost. .

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a cross-sectional view of an optical element molding apparatus capable of performing the molding method according to the present embodiment. In FIG. 2, a circular tubular upper mold 2 is movably disposed on the lower mold 1. A cylindrical movable mold 3 is slidably included with respect to the upper mold 2, and a movable mold 3 ′ is slidably included with respect to the lower mold 1.

  On the lower surface of the movable mold 3, an aspherical shape 3a of an optical element to be molded and a fine shape 3b corresponding to a shape that causes structural birefringence are formed. A heater 4 is installed inside the movable mold 3. On the upper surface of the movable mold 3 ', an aspherical shape 3a' of the optical element to be molded and a fine shape 3b 'corresponding to the diffractive structure are formed. A heater 4 'is installed inside the movable mold 3'. In the present embodiment, the lower mold 1 and the upper mold 2 constitute a fixed mold.

  FIG. 3 is a flowchart showing the molding method according to the present embodiment. With reference to FIG. 3, the forming method will be described. First, in step S101, the lower mold 1, the upper mold 2, the movable mold 3, 3 'are arranged in the state shown in FIG. 2, and so-called mold clamping is performed. Subsequently, in step S102, the resin material heated and melted by an external heating cylinder (not shown) is injected into the lower mold 1 and the upper mold 2 through the gate G (step of injecting the material).

  In step S103, the injected material is cooled (either natural cooling or forced cooling in which at least one of the movable molds 3 and 3 'is retracted to expose the material to the atmosphere). At this time, the aspherical shape 3a of the movable mold 3 is transferred to the surface of the material, but it is difficult to transfer the fine shape 3b sufficiently only by injection of the material. Therefore, in step S104, the movable molds 3 and 3 'are heated by the heaters 4 and 4' to a temperature equal to or higher than the glass transition point of the resin material (step of setting the mold temperature higher than the glass transition temperature of the material). . After that, in step S105, when the movable molds 3 and 3 ′ are pressed against the resin material at a speed of 10 mm / s or more by a driving unit (not shown), the surface of the resin material to which the fine shapes 3b and 3b ′ hit is melted. Then, it reaches the groove bottoms of the fine shapes 3b and 3b '(step of transferring the fine shapes). Therefore, even a fine shape having an aspect ratio of 1 or more and a fine shape having a radius of curvature of a corner of the cross section in the optical axis direction of 1 μm or less can be accurately transferred.

  After that, in step S106, pressure holding is performed for about 1 to 5 seconds (stationary while the movable mold is pressed against the resin material), and in step S107, the lower mold 1 to the upper mold 2 and the movable mold are used using a driving unit (not shown). An optical element that obtains a highly accurate fine shape can be formed by mold opening (releasing) for retracting 3, 3 ′.

  In the conventional injection molding, a cycle time of about several tens of seconds is required when the fine shape is not transferred, and about one minute is required when the fine shape is transferred, but according to the molding method of the present invention, In the case where the fine shape is transferred to the surface of the object that has been previously molded within the design shape error range and the shape is molded, the molding is completed in a cycle time of 1 to 10 seconds. The fact that the holding time is significantly shortened also contributes to shortening the cycle time.

  In addition, by moving the movable molds 3 and 3 'toward the resin material at a speed of 10 mm / s or more, impact energy is imparted to the resin material, thereby making the fineness of the high aspect ratio that could not be formed by the conventional technology. The shape can be accurately transferred and formed. In addition, since the time for which the heated movable molds 3 and 3 ′ are in contact with the resin material is short, even if the surface of the fine shape is melted and deformed by heat transfer from the mold, the inner part remains rigid. Therefore, by rapidly releasing the mold, the formed fine shape is maintained, and the transfer success area is increased as compared with the conventional case. Further, as a secondary effect of increasing the moving speed, the molding process time is shortened. The formed fine shape is formed with a sheared surface formed by applying impact energy.

  FIG. 4 is a diagram showing an example of an optical element molded by the above molding method. The optical element 10 having the shape shown in the perspective view of FIG. 4 (a) has a fine shape 10a of structural birefringence on the surface as shown in FIG. 4 (b). As shown, the back surface has a diffraction structure 10b having a sawtooth cross section in the optical axis direction. The fine shape 10a of structural birefringence has a ring-shaped rectangular groove, and has a cross-sectional shape shown in FIG. Here, as an example, if the refractive index of the material of the optical element 10 is 1.92 and the wavelength of incident light is λ, the dimensions of each part in the fine shape 10a of structural birefringence are d1 = 0.25λ, d2 (Groove width) = 0.39λ, d3 = 2λ, d4 (groove depth) = 1.22λ. Further, in FIG. 4C, the radius of curvature R of the corner in the cross section in the optical axis direction of the sawtooth diffraction structure 10b is less than 1 μm.

  FIG. 5 is a diagram showing another example of an optical element molded by the above molding method. The optical element 20 having the shape shown in the cross-sectional view of FIG. 5A has a diffractive structure 20a having a serrated cross section in the optical axis direction on the surface, as shown in FIG. 5B. Furthermore, a large number of conical holes 20b having a diameter reduced in the depth direction are formed on the inclined surface of the diffractive structure 20a. The hole 20b having the antireflection function occupies 20% to 40% (preferably 30%) of the area of the inclined surface.

  The inventors of the present application confirmed the effect of the present invention through experiments. 6 and 7 are graphs showing the results of experiments conducted by the present inventors. The experimental result shown in FIG. 6 shows how deep a fine shape can be formed when forming a line-shaped protrusion having a line width of 100 nm, that is, in the state shown in FIG. The level of B is obtained when the thickness is 100 nm.

On the other hand, the experimental result shown in FIG. 7 shows the transfer success area. For example, 100% indicates that the transfer is successful in the entire region, and conversely if 0%, the transfer is in the entire region. Indicates failure. The present inventors conducted an experiment using the molding apparatus shown in FIG. 2 while changing the conditions as follows.
[Test conditions]
(A) Mold temperature: 150 ° C., moving speed: 0.05 mm / s, holding pressure: 600 sec (with cooling)
(B) Mold temperature: 150 ° C., moving speed: 50 mm / s, holding pressure: 2 sec
(C) Mold temperature: 130 ° C., moving speed: 0.05 mm / s, holding pressure: 2 sec
(D) Mold temperature: 130 ° C., moving speed: 0.05 mm / s, holding pressure: 10 sec
(E) Mold temperature: 130 ° C., moving speed: 5 mm / s, holding pressure: 3 sec
(F) Mold temperature: 130 ° C., moving speed: 50 mm / s, holding pressure: 2 sec

  Referring to the graphs of FIGS. 6 and 7, at a mold temperature of 150 ° C. (conditions (a) and (b)), a high fine shape with an aspect ratio of 3.5 to 4.5 can be formed. It can be seen that there is room for improvement as low as 10 to 20%. On the other hand, at a mold temperature of 130 ° C. (conditions (c) to (f)), the aspect ratio is relatively low, 1.0 to 2.0, but the transfer success area is 100% at the maximum. It is feasible.

  Furthermore, the experimental results under the condition of a mold temperature of 130 ° C. will be examined in detail. First, when the conditions (c) and (d) are compared, when the holding pressure time is 10 sec (c), a fine shape with an aspect ratio of 2.0 can be obtained, but the transfer success rate is 30%, which is improved. It can be seen that there is room for. On the other hand, when the pressure holding time is 2 sec (d), the aspect ratio remains at 1.0, but the transfer success rate is 100%.

  Next, comparing the conditions (c) and (e), it can be seen that when the moving speed is 0.05 mm / s and 5 mm / s, the aspect ratio and the transfer success area of the formed fine shape are hardly changed. When (c) and (f) are compared, when the moving speed is changed from 0.05 mm / s to 50 mm / s, the aspect ratio of the formed fine shape increases, but the transfer success area decreases to 70%. I understand. From the above, it was found that when a fine shape having an aspect ratio of 1.5 with a line width of 100 nm is obtained with a transfer success area of 70% or more, it should be performed under the condition (f).

  FIG. 8 is a diagram showing the relationship between the phase velocity of the mold and the maximum aspect ratio (filling depth) of the fine shape to be formed, obtained by the experiments of the present inventors. As shown in FIG. 8, when the mold speed is set to 10 mm / s or more, a fine shape having a line width of 100 nm and a maximum aspect ratio of 1.1 or more can be obtained.

  The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. The present invention is not limited to an optical element for an optical pickup device, but can also be applied to molding various optical elements or an inkjet printer head.

It is a figure for demonstrating an aspect-ratio. It is sectional drawing of the shaping | molding apparatus of the optical element which can implement the shaping | molding method concerning this Embodiment. It is a flowchart figure which shows the shaping | molding method concerning this Embodiment. It is a figure which shows the example of the optical element shape | molded by the shaping | molding method concerning this Embodiment. It is a figure which shows another example of the optical element shape | molded by the shaping | molding method concerning this Embodiment. It is a graph which shows the experimental result which the present inventors conducted. It is a graph which shows the experimental result which the present inventors conducted. It is a figure which shows the relationship between the phase velocity of a type | mold obtained by experiment of the present inventors, and the maximum aspect ratio (filling depth) of the fine shape formed.

Explanation of symbols

1 Lower mold 2 Upper mold 3 Movable mold 4 Heater

Claims (17)

In a molded product formed by pressing a mold,
The elastic modulus at normal temperature is 1 to 4 (GPa), the thickness after molding is 0.1 mm or more and 20 mm or less, the aspect ratio of the fine shape formed on the molding surface is 1 or more, and the fine shape is A molded product having a fine shape characterized by having a shearing surface. The molded article according to claim 1, wherein the fine shape causes structural birefringence. The molded product according to claim 1, wherein the fine shape has a periodic structure with a size equal to or smaller than the wavelength of light and has an antireflection function. The molded article having a fine shape according to any one of claims 1 to 3, which is an optical element. In an optical element whose optical surface is molded by pressing a mold,
The elastic modulus at normal temperature is 1 to 4 (GPa), the thickness after molding is 0.1 mm or more and 20 mm or less, and the radial pitch in the annular diffraction structure formed on the optical surface is 10 μm or less. An optical element, wherein a radius of curvature of a corner portion in a cross section in the optical axis direction of the diffractive structure is less than 1 μm, and the diffractive structure has a shear plane. Setting the temperature of the mold having a fine shape higher than the glass transition temperature of the material having an elastic modulus at room temperature of 1 to 4 (GPa);
Transferring the fine shape to the material by pressing the mold toward the material at a speed of 10 mm / s or more;
Releasing the mold having the fine shape from the resin material. 2. The method according to claim 1, further comprising a step of injecting the material between the finely shaped die, a die facing the die, and a step of cooling the material before pressing the die toward the material. 6. The molding method according to 6. The molding method according to claim 6, wherein the material is a material of an optical element. The fine shape is a ring-shaped diffractive structure, the pitch of the diffractive structure in the radial direction is 10 μm or less, and the radius of curvature of the corner in the cross section in the optical axis direction of the diffractive structure is less than 1 μm. The molding method according to claim 8. The molding method according to claim 8, wherein the fine shape has an aspect ratio of 1 or more and causes structural birefringence. The molding method according to claim 8, wherein the fine shape has an aspect ratio of 1 or more, a periodic structure with a size equal to or smaller than the wavelength of light, and an antireflection function. A movable mold having a fine shape;
A stationary mold that shields the movable mold so as to surround the fine shape;
A heater for heating the movable mold;
A drive unit that relatively moves the movable mold and the fixed mold;
A material having an elastic modulus of 1 to 4 (GPa) at room temperature is disposed in a space closed by the movable mold and the fixed mold, and at least the interior of the material is solidified, and the movable by the heater. The mold is heated, and the moving part moves the movable mold relative to the material at a speed of 10 mm / s or more, whereby the fine shape of the movable mold is transferred. Forming equipment. The molding apparatus according to claim 12, wherein the material is injected into a space closed by the movable mold and the fixed mold. The molding apparatus according to claim 12, wherein the material is a material of an optical element. The fine shape is a ring-shaped diffractive structure, the pitch of the diffractive structure in the radial direction is 10 μm or less, and the radius of curvature of the corner in the cross section in the optical axis direction of the diffractive structure is less than 1 μm. The molding apparatus according to claim 14. The molding apparatus according to claim 14, wherein the fine shape has an aspect ratio of 1 or more and causes structural birefringence. The molding apparatus according to claim 14, wherein the fine shape has an aspect ratio of 1 or more, has a periodic structure with a size equal to or smaller than the wavelength of light, and has an antireflection function.

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