JP2014024223A - Optical element manufacturing method and optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element manufacturing method to reduce production cost.SOLUTION: The optical element manufacturing method to form, by curing resin material, a DOE molding section stacked on a glass substrate comprises supplying the resin material which is molding material to the surface of the glass substrate formed almost in a disk shape, spreading the resin material by bringing a mold 50 to the surface of the resin-supplied glass substrate, and curing the spread resin material. In the mold 50, a groove section 52 with a pair of wall surfaces of V-shaped cross-section is extending like a circular ring in a facing surface section 53 facing the periphery vicinity of the glass substrate.

Description

  The present invention relates to an optical element and a method for manufacturing the same.

  For manufacturing an optical element, molding is often used (see, for example, Patent Document 1). For example, when molding a composite type diffractive lens using a glass material and a resin material, the mold is pressed against a resin material applied on a disk-shaped glass substrate, and formed on the transfer surface of the mold. The predetermined shape (that is, the shape of the diffraction grating) is transferred to the resin material. After forming the disk-shaped resin layer to which the shape of the diffraction grating is transferred in this way, it is inspected whether the diffraction grating is formed at the center of the diffraction lens (glass substrate).

JP 2007-131466 A

  Despite the fact that the diffraction grating is formed at the center of the glass substrate, the resin material is spread unevenly by the molding die, and the outer peripheral portion of the molded resin layer is eccentric with respect to the outer peripheral portion of the glass substrate. There may be deviation. On the other hand, a method in which an excessively large glass substrate is prepared in advance in anticipation of the deviation of the resin layer after molding, and the glass substrate (resin layer if necessary) is cut to a predetermined size after molding the resin layer. Can be considered. However, in such a method, it takes time to cut the glass substrate, and the yield of the material of the glass substrate decreases, which contributes to an increase in manufacturing cost.

  The present invention has been made in view of such problems, and an object thereof is to provide an optical element manufacturing method and an optical element capable of reducing manufacturing costs.

  In order to achieve such an object, an optical element manufacturing method according to the present invention supplies a molding material to the surface of a first member formed in a substantially disc shape, and the first member to which the molding material is supplied is supplied. An optical for forming a molding material close to the first member by bringing a molding die close to the surface to spread the molding material and curing the spread molding material. A method for manufacturing an element, comprising: a pair of wall surfaces having a V-shaped cross-sectional view in the vicinity of the outer peripheral portion of the surface of the first member, or on the facing surface portion facing the vicinity of the outer peripheral portion of the first member in the mold The groove part which has is extended in the annular | circular shape, and the following conditional expressions are satisfied.

3 ° ≦ θ1 ≦ 60 °
3 ° ≦ θ2 ≦ 60 °
30 ° ≦ θ1 + θ2 ≦ 120 °
However,
θ1: an inclination angle to one wall surface of the pair of V-shaped wall surfaces in cross section,
θ2: An inclination angle of the pair of V-shaped wall surfaces to the other wall surface in the cross-sectional view.

  In the above-described manufacturing method, it is preferable that the groove portion has an arc-shaped bottom surface connected to the pair of V-shaped wall surfaces when viewed in cross section and satisfies the following conditional expression.

0.5μm ≦ R ≦ 5μm
However,
R: radius of curvature of the bottom surface.

  Further, in the above manufacturing method, the mold has a transfer surface portion having a shape for transferring a predetermined element shape required for the optical element, and the groove portion is opposed to the mold. The surface portion is preferably formed in an annular shape surrounding the transfer surface portion.

  Further, the transfer surface portion is formed in a circular shape, the rotational symmetry axis of the groove is coaxial with the rotational symmetry axis of the transfer surface portion, and when the mold is brought close to the surface of the first member, the transfer surface portion and It is preferable that the rotational symmetry axis of the groove is arranged so as to be coaxial with the rotational symmetry axis of the first member.

  In the manufacturing method described above, the predetermined element shape is preferably a diffraction grating shape constituting a diffractive optical element.

  In the manufacturing method described above, it is preferable to use an ultraviolet curable resin as the molding material.

  Moreover, the optical element according to the present invention is manufactured using the method for manufacturing an optical element according to the present invention.

  According to the present invention, it becomes possible to reduce the manufacturing cost of an optical element.

It is a sectional side view of the shaping | molding die in 1st Embodiment. It is a sectional side view of a diffractive lens. It is a fragmentary sectional view (enlarged view) of the shaping | molding die in 1st Embodiment. It is an expanded sectional view of a groove part. It is a flowchart which shows the manufacturing method of a diffractive lens. It is the schematic diagram shown to (a)-(d) in order about the formation process of the diffraction lens in 1st Embodiment. It is a schematic diagram which shows the modification of the shift inspection process in 1st Embodiment. It is a plane sectional view showing the example which formed the DOE fabrication part on the glass substrate. It is an expanded sectional view which shows the modification of a groove part. It is the schematic diagram shown to (a)-(d) in order about the formation process of the diffraction lens in 2nd Embodiment. It is a sectional side view showing an example of a phase Fresnel lens. It is a sectional side view showing an example of a phase Fresnel lens.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. A diffractive lens 1 is shown in FIG. 2 as an optical element of the present embodiment. The diffractive lens 1 includes a DOE molding part 2 that constitutes a diffractive optical element (DOE) and a transparent support part 3 that supports the DOE molding part 2. The DOE molding part 2 is molded into a disk shape using a transparent resin material, and a diffraction grating 21 in which a plurality of annular zones are arranged concentrically is formed on the surface of the DOE molding part 2. In each figure, for ease of explanation, the number of annular zones of the diffraction grating 21 is described to be small, but the actual number of annular zones is assumed to be sufficiently large to be usable. The support portion 3 is made of a transparent glass substrate or the like, and is formed in a disk shape having a slightly larger diameter (or the same diameter as the DOE molding portion 2) than the DOE molding portion 2.

  As a first embodiment of the method for manufacturing the diffractive lens 1, a molding die 50 used for molding the DOE molding unit 2 is shown in FIG. The mold 50 in the first embodiment is a mold (also referred to as a stamper) formed in a disk shape as shown in FIG. 1, and the DOE molding section 2 is provided on the surface side of the mold 50. In addition to the transfer surface portion 51 having a shape (inverted shape) for transferring the shape of the (diffraction grating 21), a plurality of groove portions 52 extending in an annular shape surrounding the transfer surface portion 51 are formed. The transfer surface portion 51 has a circular transfer surface 51a formed in accordance with the shape of the DOE molding portion 2 (diffraction grating 21).

  As shown in FIG. 3, the plurality of groove portions 52 surrounding the transfer surface portion 51 are formed in concentric circles arranged at equal pitch intervals in the radial direction of the mold 50. As shown in FIG. 4, each groove portion 52 has a pair of wall surfaces 52a and 52b having a V-shaped cross-sectional view and a bottom surface 52c having an arc-shaped cross-sectional view connected to the pair of wall surfaces 52a and 52b. In the present embodiment, an axis that extends in the depth direction of the groove 52 (parallel to the rotational symmetry axis of the groove 52) and passes through the center of the bottom surface 52c is referred to as a reference axis Sx. One of the pair of wall surfaces 52a and 52b of each groove 52 (left side in FIG. 4) is referred to as a first wall surface 52a, and the other wall surface (right side in FIG. 4) is referred to as a second wall surface 52b.

  The transfer surface portion 51 and the groove portion 52 are formed in the same process by performing cutting while rotating around the rotational symmetry axis of the mold 50 using a precision lathe (not shown). For this reason, the rotational symmetry axis of the groove portion 52 is formed so as to be coaxial with the rotational symmetry axis of the transfer surface portion 51.

  A method of manufacturing the diffractive lens 1 in the first embodiment will be described with reference to the flowchart shown in FIG. First, a resin material 20 for molding the DOE molding part 2 and a glass substrate 30 to be the support part 3 are prepared in advance, and then a projecting annular zone as shown in FIG. The DOE molding part 2a having 22 is molded (step ST101).

  In this forming step, first, as shown in FIG. 6A, the glass substrate 30 is placed on a stage (not shown). Here, the glass substrate 30 is a transparent glass substrate formed in a disk shape. Next, as shown in FIG. 6 (b), an uncured (liquid) resin material 20 having an ultraviolet curing property for molding the DOE molded portion 2 a is applied to the center of the surface of the glass substrate 30. In addition, an ultraviolet curable resin is used as a molding material (resin material 20) used for the DOE molding part 2a. Next, as shown in FIG. 6C, the molding die 50 is brought close to the surface of the glass substrate 30 coated with the resin material 20 from above, and the resin material 20 is pushed out in a substantially disk shape. In this state, ultraviolet rays are irradiated from the back surface side of the glass substrate 30 toward the resin material 20 by a predetermined irradiation amount, the uncured resin material 20 is cured, and then released. Then, the shape of the diffraction grating 21 is transferred to the resin material 20 by the transfer surface 51 a of the mold 50 coming into contact with the resin material 20, and a part of the resin material 20 that is spread by the mold 50 is formed in the mold 50. It enters into the groove portion 52. Therefore, as shown in FIG. 6 (d), a DOE forming portion 2 a having a protruding annular zone 22 surrounding the diffraction grating 21 is formed on the glass substrate 30.

  In this way, the DOE forming part 2a as shown in FIG. 6 (d) is formed on the glass substrate 30. Thereafter, the shift amount of the central axis AX2 of the diffraction grating 21 with respect to the central axis AX1 of the glass substrate 30 is measured (step ST102). In this shift inspection process, when the obtained shift amount is within a predetermined threshold range, it is determined as normal, and when the obtained shift amount exceeds the predetermined threshold value, it is determined as abnormal. Then, after measuring the shift amount, the DOE molding is performed through a finishing process for cutting the outer periphery of the DOE molding part 2a including the glass substrate 30 and the protruding annular zone 22 with a lathe, a final product inspection process, and the like. The diffractive lens 1 including the part 2 and the support part 3 is manufactured.

  In the first embodiment, a circular transfer surface portion 51 is formed in the center portion on the surface side of the mold 50. An annular groove 52 surrounding the transfer surface portion 51 is coaxial with the transfer surface portion 51 in the vicinity of the outer peripheral portion on the surface side of the mold 50, that is, on the facing surface portion 53 facing the vicinity of the outer periphery of the glass substrate 30 in the mold 50. Formed. Therefore, when the molding die 50 is brought close to the surface of the glass substrate 30, if the rotational symmetry axes of the transfer surface portion 51 and the groove portion 52 are arranged so as to be coaxial with the rotational symmetry axis of the glass substrate 30, the molding die 50 becomes the resin material 20. When the resin material 20 is spread, a part of the resin material 20 enters the groove portion 52 connected in an annular shape, so that the resin material 20 can be uniformly spread (rotationally symmetric). Thereby, not only the diffraction grating 21 but also the DOE molding portion 2 a itself is formed coaxially with the glass substrate 30. As a result, according to the first embodiment, it is not necessary to manufacture the glass substrate 30 in advance excessively in anticipation of the shift of the DOE molding portion 2a. The yield of the material of the substrate 30 is improved, and the manufacturing cost of the diffractive lens 1 can be reduced.

  In addition, it is preferable that the 1st wall surface 52a and the 2nd wall surface 52b of each groove part 52 are formed so that the conditions represented by following conditional expression (1)-(3) may be satisfied. However, the inclination angle from the reference axis Sx to the first wall surface 52a is θ1, and the inclination angle from the reference axis Sx to the second wall surface 52b is θ2 (see FIG. 4).

3 ° ≦ θ1 ≦ 60 ° (1)
3 ° ≦ θ2 ≦ 60 ° (2)
30 ° ≦ θ1 + θ2 ≦ 120 ° (3)

  If the groove portion 52 is formed so as to satisfy the conditions expressed by the conditional expressions (1) to (3), the resin material 20 can easily flow along the groove portion 52, so that the resin material 20 is more uniformly (rotated). (Symmetrically) can be spread out, and as described above, the manufacturing cost of the diffractive lens 1 can be reduced. Moreover, since the mold release can be easily performed, the diffractive lens 1 can be easily manufactured.

  Moreover, it is preferable that the bottom surface 52c of each groove part 52 is formed so that the conditions represented by the following conditional expression (4) may be satisfied. However, the radius of curvature of the bottom surface 52c is R (see FIG. 4).

  0.5 μm ≦ R ≦ 5 μm (4)

  If the groove 52 is formed so as to satisfy the condition expressed by the conditional expression (4), the groove 52 can be easily processed without impairing the ease of flow of the resin material 20 in the groove 52. The diffractive lens 1 can be easily manufactured.

  Further, in the shift inspection process in the first embodiment, the shift amount of the central axis AX2 of the diffraction grating 21 with respect to the central axis AX1 of the glass substrate 30 is measured using the annular zone 22 formed in the DOE molding portion 2a. Can do. Specifically, as shown in FIG. 7, first, using a shift inspection camera (not shown), a high-magnification enlarged image including the outer peripheral portion of the glass substrate 30 and the annular zone 22 is displayed at a plurality of measurement positions (for example, 90 Images are taken at four measurement positions at intervals of degrees. When a plurality of (four) enlarged images A1 to A4 including the outer peripheral portion of the glass substrate 30 and the annular zone 22 are imaged, the glass substrate at each measurement position is obtained by performing image processing on each of the enlarged images A1 to A4. The distances L1 to L4 in the radial direction between the outer peripheral portion 30 and the annular zone 22 (the outermost zone among the plurality of annular zones 22) are measured.

  The mold 50 of the first embodiment has a transfer surface portion 51 and a groove portion 52 coaxial with the transfer surface portion 51, and an annular ring zone 22 surrounding the diffraction grating 21 is formed coaxially with the diffraction grating 21. The Therefore, the shift amount can be measured with high accuracy via the annular zone 22 based on the high-magnification enlarged images A1 to A4 including the outer peripheral portion of the glass substrate 30 and the annular zone 22. At this time, since the outer peripheral portion of the glass substrate 30 and the annular zone 22 are circular, the central axis AX2 of the diffraction grating 21 (that is, the central axis of the annular zone 22) is aligned with the central axis AX1 of the glass substrate 30. The distances L1 to L4 in the radial direction at each measurement position are the same, but when the central axis AX2 of the diffraction grating 21 is shifted with respect to the central axis AX1 of the glass substrate 30, the radial direction at each measurement position. The intervals L1 to L4 are different. Accordingly, the shift amount can be obtained with high accuracy based on the radial intervals L1 to L4 at the plurality of measurement positions.

  Note that the measurement of the shift amount is not limited to the method described above. For example, a high-magnification enlarged image including the outer peripheral portion of the glass substrate 30 and the annular zone 22 is captured at three measurement positions at intervals of 120 degrees. The distance in the radial direction at each measurement position may be measured, and images may be taken at a plurality of measurement positions. In addition, for example, by using a shift inspection camera, an image including the outer periphery of the glass substrate 30 and the outer periphery of the diffraction grating 21 is captured, and predetermined image processing is performed on the image. You may make it measure the space | interval of the radial direction of an outer peripheral part and the outer peripheral part of the diffraction grating 21 in several measurement positions (positions which differ in the circumferential direction).

  By the way, the inventor of this application experimented about the manufacturing method of the diffraction lens 1 which concerns on 1st Embodiment. First, as shown in FIG. 3, the total width of the plurality of grooves 52: L = 2 mm, the pitch of the grooves 52: P = 0.04 mm, the depth of the grooves 52: h = 0.02 mm, The mold 50 was produced so that the innermost diameter: φ1 = 16.6 mm and the outermost diameter of the plurality of groove portions 52: φ2 = 18.6 mm. Further, as shown in FIG. 4, the inclination angle from the reference axis Sx to the first wall surface 52a: θ1 = 45 °, the inclination angle from the reference axis Sx to the second wall surface 52b: θ2 = 45 °, and the curvature radius of the bottom surface 52c. : The groove 52 was formed so that R = 1 μm. A glass substrate 30 having a diameter of 28 mm and a thickness of 2.8 mm was prepared in advance. In addition, an uncured resin material 20 having a viscosity at 25 ° C. of 500 mPa · s was prepared in advance. Then, in the same manner as in the first embodiment described above, the uncured resin material 20 is applied to the center of the surface of the glass substrate 30, and the molding material 50 is brought close to the surface of the glass substrate 30 from above to substantially reduce the resin material 20. A DOE molded part 2 a having a thickness of 0.1 mm was formed on the glass substrate 30 by spreading it into a disk shape.

  Here, as shown in FIG. 8, the maximum distance between the central axis (rotation symmetry axis) of the glass substrate 30 and the outer periphery of the DOE molding portion 2a is Dmax, and the central axis of the glass substrate 30 and the outer periphery of the DOE molding portion 2a. Let Dmin be the minimum distance to the part. A plurality of samples were produced under the above-described experimental conditions, and Dmax and Dmin were measured. As a result, the average difference between Dmax and Dmin was 0.59 mm, and the standard deviation was 0.17. According to this embodiment, it turns out that the shift amount (eccentricity) of the DOE shaping | molding part 2a (outer peripheral part) with respect to the glass substrate 30 (outer peripheral part) will be 1 mm or less.

  In the first embodiment described above, the glass substrate 30 is used as the support portion 3. However, the present invention is not limited to this. For example, a plastic substrate may be used as long as it is a transparent material. .

  Moreover, in the above-mentioned 1st Embodiment, although the DOE shaping | molding part 2 and the support part 3 (DOE shaping | molding part 2a and the glass substrate 30) are each formed in disk shape, it is not restricted to this, At least these of these Either surface may be spherical or aspheric.

  Further, in the first embodiment described above, the plurality of groove portions 52 are arranged at equal pitch intervals in the radial direction of the mold 50. However, the present invention is not limited to this and may not be equal pitch. Moreover, the groove part 52 may be single according to conditions.

  In the first embodiment described above, after measuring the shift amount, the outer peripheral portion of the DOE molding portion 2a including the annular zone 22 is cut. However, the present invention is not limited to this, and there is no problem in optical performance. For example, the annular zone 22 may be left without cutting the outer peripheral portion.

  Further, in the first embodiment described above, the cross section of the groove 52 is formed symmetrically. However, the present invention is not limited to this, and the groove 52 may be formed asymmetrical. For example, as shown in FIG. 9A, the first wall surface 52a ′ of the groove portion 52 may be inclined with respect to the second wall surface 52b ′. For example, as shown in FIG. The two wall surfaces 52b ″ may be inclined with respect to the first wall surface 52a ″. That is, the groove 52 may be formed so as to satisfy the conditions represented by the conditional expressions (1) to (3) described above.

  Then, 2nd Embodiment of the manufacturing method of the diffraction lens 1 is described. The manufacturing flow in the second embodiment is different from the manufacturing flow in the first embodiment in that a shift inspection process is not provided. First, the resin material 20 for molding the DOE molding part 2 and the glass substrate 60 to be the support part 3 are prepared in advance, and then the annular zone 63 as shown in FIG. The DOE molding part 2b that is provided on the side is molded.

  The mold 55 according to the second embodiment is a mold formed in a disk shape as shown in FIG. 10B, and the shape of the DOE molding part 2 (diffraction grating 21) is formed on the surface side of the mold 55. Only the transfer surface portion 51 having a shape (inverted shape) for transferring the image is formed. The transfer surface portion 51 of the second embodiment is formed in the same manner as in the first embodiment, and has a circular transfer surface 51a formed in accordance with the shape of the DOE molding portion 2 (diffraction grating 21).

  The glass substrate 60 of the second embodiment is a transparent glass substrate formed in a disc shape as shown in FIG. 10A, and a plurality of groove portions 62 are provided in the vicinity of the outer peripheral portion on the surface side of the glass substrate 60. It is formed to extend in an annular shape. The groove portions 62 of the second embodiment are formed in concentric circles arranged at equal pitch intervals in the radial direction of the glass substrate 60. Each groove portion 62 has the same shape (vertically inverted shape) as the groove portion 52 of the first embodiment and is not shown in detail, but is connected to a pair of V-shaped wall surfaces in cross section and the pair of wall surfaces. And a bottom surface having an arc shape in cross section. Moreover, in the groove part 62 of 2nd Embodiment, a reference axis, a 1st wall surface, and a 2nd wall surface shall be defined similarly to the groove part 52 of 1st Embodiment, These detailed description and illustration are abbreviate | omitted.

  In addition, the groove part 62 of 2nd Embodiment grinds, rotating around the rotational symmetry axis of the glass substrate 60 using a grinder which is not illustrated, so that the rotational symmetry axis of the groove part 62 is the same as that of the glass substrate 60. It is formed so as to be coaxial with the rotational symmetry axis.

  In the molding process of the second embodiment, first, as shown in FIG. 10A, the glass substrate 60 is placed on a stage (not shown). Next, as shown in FIG. 10B, an uncured (liquid) resin material 20 similar to that of the first embodiment is applied to the center of the surface of the glass substrate 60. Next, as shown in FIG. 10C, the molding die 55 is brought close to the surface of the glass substrate 30 coated with the resin material 20 from above to spread the resin material 20 in a substantially disk shape. In this state, ultraviolet rays are irradiated from the back surface side of the glass substrate 60 toward the resin material 20 by a predetermined irradiation amount, the uncured resin material 20 is cured, and then released. Then, the shape of the diffraction grating 21 is transferred to the resin material 20 by the transfer surface 51 a of the mold 55 coming into contact with the resin material 20, and a part of the resin material 20 that is spread by the mold 55 is part of the glass substrate 60. The groove 62 enters. Therefore, as shown in FIG. 10 (d), a DOE molding portion 2b having an annular zone 63 that is visually recognized so as to surround the diffraction grating 21 on the glass substrate 60 is molded.

  In this manner, the DOE forming portion 2b as shown in FIG. 10 (d) is formed on the glass substrate 60. After that, a diffractive lens composed of the DOE molding part 2 and the support part 3 is subjected to a finishing process for cutting the outer peripheral part of the DOE molding part 2b including the glass substrate 60 and the annular zone 63 by a lathe, a final product inspection process, and the like. 1 is manufactured.

  In the second embodiment, an annular groove 62 having a diameter larger than that of the transfer surface portion 51 of the molding die 55 is formed coaxially with the glass substrate 60 in the vicinity of the outer peripheral portion of the glass substrate 60. Therefore, when the molding die 55 is brought close to the surface of the glass substrate 60, if the rotational symmetry axis of the transfer surface portion 51 is arranged so as to be coaxial with the rotational symmetry axis of the glass substrate 60, the molding die 55 spreads the resin material 20. At this time, since a part of the resin material 20 enters the groove portion 62 connected in an annular shape, the resin material 20 can be uniformly spread (rotationally symmetric). Thereby, not only the diffraction grating 21 but also the DOE molding part 2 b itself is formed coaxially with the glass substrate 60. As a result, according to the second embodiment, the manufacturing cost of the diffractive lens 1 can be reduced as in the first embodiment.

  In addition, it is preferable that the 1st wall surface and 2nd wall surface of each groove part 62 are formed so that the conditions represented by the above-mentioned conditional expression (1)-(3) may be satisfied. As in the first embodiment, the inclination angle from the reference axis to the first wall surface in the groove 62 is θ1, and the inclination angle from the reference axis to the second wall surface is θ2. In this way, the manufacturing cost of the diffractive lens 1 can be reduced as in the first embodiment. Moreover, since the mold release can be easily performed, the diffractive lens 1 can be easily manufactured.

  In addition, the bottom surface of each groove 62 is preferably formed so as to satisfy the condition represented by the conditional expression (4). Note that the radius of curvature of the bottom surface of the groove 62 is R, as in the first embodiment. In this way, the diffractive lens 1 can be easily manufactured as in the first embodiment.

  In the second embodiment described above, the glass substrate 60 is used as the support portion 3, but is not limited to this. For example, a plastic substrate may be used as long as it is a transparent material. .

  Further, in the second embodiment described above, the DOE molding part 2 and the support part 3 (DOE molding part 2b and glass substrate 60) are each formed in a disk shape, but are not limited thereto, and at least these Either surface may be spherical or aspheric.

  In the second embodiment described above, the plurality of groove portions 62 are arranged at equal pitch intervals in the radial direction of the glass substrate 60. However, the present invention is not limited to this and may not be equal pitch. Moreover, the groove part 62 may be single according to conditions.

  In the second embodiment described above, the outer peripheral portion of the DOE molding portion 2b including the annular zone 63 is cut. However, the present invention is not limited to this, and if there is no problem in optical performance, the outer peripheral portion can be cut. Instead, the annular zone 63 may be left.

  Further, in the second embodiment described above, the cross section of the groove 62 is formed symmetrically. However, the present invention is not limited to this, and may be formed asymmetrical as in the first embodiment. That is, the groove portion 62 may be formed so as to satisfy the conditions expressed by the above conditional expressions (1) to (3).

  In the first and second embodiments described above, the diffractive lens 1 having the single-layer DOE molded portion 2 has been described as an example. The present invention can be applied even to a PF lens. For example, as shown in FIG. 11, a first DOE layer 72 and a first DOE layer 72 formed by the above-described mold 50 (or mold 55) using a resin material having a low refractive index and high dispersion are used. A first support layer 73 which is a glass substrate to be supported, a second DOE layer 74 laminated on the first DOE layer 72 using a resin material having a high refractive index and low dispersion, and a second DOE layer 74 It may be a PF lens 71 having a second support layer 75 that is a glass substrate to be supported. Further, for example, as shown in FIG. 12, a first DOE layer 82 and a first DOE layer 82 formed by the above-described mold 50 (or mold 55) using a resin material having a low refractive index and high dispersion. Even a PF lens 81 having a support layer 83 that is a glass substrate that supports the second DOE layer 84 laminated on the first DOE layer 82 using a resin material having a high refractive index and low dispersion. Good.

  In the first and second embodiments described above, the diffractive lens 1 which is a kind of diffractive optical element has been described as an example. However, the present invention is not limited to this, and a general Fresnel lens, an aspheric lens, a micro lens, The present invention can also be applied to an optical element such as a lens array.

1 Diffraction lens (optical element)
2 DOE molding part 3 Support part 20 Resin material (molding material)
21 Diffraction grating 22 Ring zone 30 Glass substrate (first embodiment)
50 Mold (first embodiment)
51 Transfer surface (51a Transfer surface)
52 Groove (52a first wall surface, 52b second wall surface, 52c bottom surface)
55 Mold (Second Embodiment)
60 Glass substrate (second embodiment)
62 Groove 71 PF lens (modified example of diffractive optical element)
81 PF lens (modified example of diffractive optical element)

Claims (7)

A molding material is supplied to the surface of the first member formed in a substantially disc shape, and a molding die is brought close to the surface of the first member to which the molding material is supplied to spread the molding material, and the spread A method for producing an optical element, wherein a second member obtained by curing the molding material is overlaid on the first member by curing the molding material,
A groove portion having a pair of V-shaped wall surfaces in a cross-sectional view extends in an annular shape in the vicinity of the outer peripheral portion of the surface of the first member or in the opposing surface portion facing the vicinity of the outer peripheral portion of the first member in the mold. Formed,
The manufacturing method of the optical element characterized by satisfying the following conditional expressions:
3 ° ≦ θ1 ≦ 60 °
3 ° ≦ θ2 ≦ 60 °
30 ° ≦ θ1 + θ2 ≦ 120 °
However,
θ1: an inclination angle to one wall surface of the pair of V-shaped wall surfaces in cross section,
θ2: An inclination angle of the pair of V-shaped wall surfaces to the other wall surface in the cross-sectional view. The groove portion has a bottom in an arc shape in cross section connected to a pair of wall surfaces in the V shape in cross section,
The optical element manufacturing method according to claim 1, wherein the following conditional expression is satisfied.
0.5μm ≦ R ≦ 5μm
However,
R: radius of curvature of the bottom surface. The molding die has a transfer surface portion having a shape for transferring a predetermined element shape required for the optical element,
3. The method of manufacturing an optical element according to claim 1, wherein the groove portion is formed in an annular shape surrounding the transfer surface portion on the facing surface portion of the mold. The transfer surface portion is formed in a circular shape,
The rotational symmetry axis of the groove is coaxial with the rotational symmetry axis of the transfer surface,
4. When the mold is brought close to the surface of the first member, the rotational symmetry axis of the transfer surface portion and the groove portion is arranged so as to be coaxial with the rotational symmetry axis of the first member. The manufacturing method of the optical element of description.   5. The method of manufacturing an optical element according to claim 1, wherein the predetermined element shape is a diffraction grating shape constituting the diffractive optical element.   6. The method for manufacturing an optical element according to claim 1, wherein an ultraviolet curable resin is used as the molding material.   It manufactures using the manufacturing method of the optical element as described in any one of Claim 1 to 6, The optical element characterized by the above-mentioned.

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