JP2006138924A - Composite type diffraction optical element by light energy setting type resin and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily adjust the position of each grating plane in a stacked diffraction optical element in a short period of time. <P>SOLUTION: The alignment of each grating plane in an adhesion type stacked diffraction grating in molding is performed in such a manner that a projecting part or a hole part having a width of ≤30 μm has been formed in the center of resin with the grating formed, and the projecting part or the hole part is fitted to a hole part or a projecting part provided in the center of a die for resin molding to be stacked, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a diffractive optical element and a method for manufacturing the same, and more particularly to a diffractive optical element used for a plurality of wavelengths or band lights and a method for manufacturing the same.

  Since the diffractive optical element uses the diffraction action to control the light beam, the diffracted light is divided into a plurality of orders of light. For example, when used as a lens for a camera or the like, the separated light becomes unnecessary light, and the optical performance is reduced. It will deteriorate. Therefore, when using a diffractive optical element as a lens system, it is necessary to determine the grating structure (grating height) and the optical characteristics (refractive index and dispersion) of the material so that the light flux in the wavelength range to be used is concentrated in a specific order. is there. As a method for improving the diffraction efficiency for this specific order, in Japanese Patent Laid-Open No. 9-127322 and Japanese Patent No. 3472902, the diffraction efficiency is improved by laminating different materials and forming a diffraction grating surface on each material. (Hereinafter referred to as a laminated diffractive optical element). As a method of manufacturing such a laminated diffractive optical element, a method of forming a desired surface shape by forming a thin layer of a light energy curable resin on a substrate and curing it as in JP-A-2001-141918 is used. .

If the diffraction grating planes of different materials laminated here are misaligned in the direction perpendicular to the optical axis, the diffracted light other than the specific order increases, resulting in a decrease in optical performance. Therefore, regarding the alignment of the grating surface, in Japanese Patent Laid-Open No. 2001-141918, a convex portion or a concave portion is formed on one grating surface outside the optically effective area, that is, outside the grating surface, and a diffraction grating surface made of another material is formed on this. The mold used for molding is provided with a concave portion or a convex portion corresponding to the convex portion or the concave portion, and the positioning is performed by fitting the concave portion or the convex portion.
JP-A-9-127322 Japanese Patent No. 3472922 JP-A-2001-141918

  3A is a front view, and FIG. 3B is a cross-sectional view of a concentric laminated diffractive optical element. The alignment of the lattice surface 23a of the formed first layer resin 23 and the lattice surface of the lattice forming mold used when forming the second layer 24 is outside the effective optical diameter as in the conventional example. In other words, when performing on the outside of the lattice plane, the mold and the lattice plane must be aligned with at least two alignment marks or uneven portions used for fitting. In addition, at least triaxial adjustment of xy-θ is necessary and time is required, and the positional deviation between the two alignment marks and the optical axis center is directly added to the alignment accuracy. Big element In the more unfavorable.

  Therefore, in the first and second aspects of the present invention, a protrusion or hole having a width of 30 μm or less is formed by molding in the resin center where the lattice is formed, and a hole provided in the mold center for resin molding to be laminated with this. Positioning is performed by fitting the part or the protrusion. Since the size is 30 μm or less and the optical performance is not affected and the alignment is performed at the center of the optical axis, only one alignment and xy biaxial adjustment are required. In addition, because it is aligned at one center, there is little deviation from the center of the optical axis of the diffraction grating of the mold hole or protrusion, especially in the case of bite machining while rotating the mold material as a mold manufacturing method. In most cases, this shift disappears.

  According to the third and fourth aspects of the present invention, the center of the optical axis of the diffraction grating surface of the mold coincides with the axis of the outer shape of the mold, and the outer shape of the base material forming the grating surface and the outer shape of the mold are fitted to each other. By performing the alignment, the center of the optical axis of the grating forming surface and the substrate outer shape are positioned in the order of several tens of μm. Further, the protrusion or hole provided at the center of the optical axis of the diffraction grating surface of the mold and the hole or protrusion of the resin center that has already been molded are positioned using position recognition by image processing. Positioning by external shape enables rough positioning for position recognition by image recognition, and positioning by submicron order can be performed in a short time by position recognition by image processing.

  As described above, according to the first to fourth inventions of the present application, since the position adjustment of each grating surface of the laminated diffractive optical element is one place and xy biaxial adjustment, it can be easily adjusted in a short time. It becomes possible.

Example 1
FIG. 1 is a schematic view (cross-sectional view) showing one embodiment of a shape of a laminated diffractive optical element and a manufacturing method thereof according to the present invention. In FIG. 1, 1 is a mold for molding the lattice plane of the first layer, 2 is a glass substrate on which resin is molded on the surface, 3 is a ring for fitting and aligning the mold and the glass substrate, and 4 is the first layer. UV curable resin used for forming the eye, 5 is a glass substrate on which the first layer is formed, 6 is a first resin layer which is formed and cured and the surface is a diffraction grating surface, and 7 is a second layer. 8 is an ultraviolet curable resin used for molding the second layer, 9 is a laminated diffractive optical element in which two types of grating surfaces are formed by molding, and 10 is molded and cured. The second resin layer whose surface is a diffraction grating surface. First, the mold 1 is set in the ring 3 as shown in FIG. Here, the outer shape 1c of the mold is processed to be slightly smaller than the inner surface 3a of the ring, and the clearance is 10 μm. In addition, since the protrusion 1a having a width of 30 μm formed at the center of the mold and the axis of the grating forming surface 1b (symmetrical shape of rotation) and the outer shape 1c of the mold are processed with a coaxiality of 0.5 μm or less, The protrusions at the center of the mold and the grid forming surface with respect to the inner surface are set with a maximum axial misalignment of about 5.5 μm. Here, a required amount of the ultraviolet curable resin 4 is dropped onto the mold 1 using a resin supply device (not shown). (FIG. 1B) Next, as shown in FIG. 1C, the glass substrate is fitted in the ring and brought into contact with the resin 4, and then the ultraviolet curable resin 4 is cured by irradiation with ultraviolet rays. Here, the resin thickness is determined by the glass substrate coming into contact with the outer peripheral projection 1d of the mold. The glass substrate 5 on which the resin was molded was released by an ejector mechanism (not shown). (FIG. 1 (d)) Since the outer shape of the glass substrate was 20 μm smaller than the inner surface of the ring, the resin lattice plane 6b and the hole 6a at the center of the resin formed on the outer shape of the glass were at most 15.5 μm. It is formed with a certain degree of axial misalignment. Next, as shown in FIG. 1E, the mold is replaced with a mold 7 for forming the second layer, and a required amount of the ultraviolet curable resin 8 is dropped onto the mold 7 using a resin supply device (not shown). This second layer mold is also processed slightly smaller than the inner surface of the ring, and the clearance is 7 μm. Further, the projection 7a having a width of 30 μm formed at the center of the mold and the axis of the lattice forming surface 7b (symmetrical shape of rotation) and the outer shape 7c of the mold are processed with a coaxiality of 0.5 μm or less, so that the ring The protrusion at the center of the mold and the grid forming surface with respect to the inner surface are set with an axis deviation of about 4 μm at the maximum. Next, the glass substrate on which the first layer is formed is fitted into the ring. (FIG. 1 (f)) In this state, an image recognition device (not shown) is used to detect the misalignment between the projection 7a at the center of the mold and the hole 6a at the center of the resin formed at the first layer molding, and a handling mechanism (not shown) After adjusting the position of the protrusion 7a and the hole 6a to 1 μm or less, the liquid 8 was in contact with the resin 8 and the protrusion 7a in the mold center and the hole 6a in the first resin center were fitted together The resin 8 was cured by irradiating with ultraviolet rays. (FIG. 1 (g)) Here, the resin thickness is determined by the glass substrate coming into contact with the outer peripheral projection 7d of the mold. The glass substrate 9 having a hole 9a having a width of 30 μm in the center and molded with resin was released by an ejector mechanism (not shown). The formed multilayer diffraction grating 9 has a measurement result of a positional deviation between the first-layer grating surface 6a and the second-layer grating surface 10a of 1 μm or less. It was 1% or less, and there was no performance deterioration due to the hole at the center of the resin.

(Example 2)
FIG. 2 is a schematic view (cross-sectional view) showing an embodiment of the second shape of the laminated diffractive optical element and the manufacturing method thereof according to the present invention. In FIG. 2, 11 is a mold for forming the lattice plane of the first layer, 12 is a glass substrate on which resin is formed on the surface, 13 is a ring for fitting and aligning the mold and the glass substrate, and 14 is the first layer. UV curable resin used for forming the eye, 15 is a glass substrate on which the first layer is formed, 16 is a first resin layer which is formed and cured and has a diffraction grating surface, and 17 is a second layer. 18 is an ultraviolet curable resin used for molding the second layer, 19 is a laminated diffractive optical element in which two types of grating surfaces are formed by molding, and 20 is molded and cured. This is a second resin layer whose surface is a diffraction grating surface. First, the die 11 is set in the ring 13 as shown in FIG. Here, the outer shape 11c of the mold is processed to be slightly smaller than the inner surface 13a of the ring, and the clearance is 10 μm. Further, the hole 11a having a width of 30 μm formed in the center of the mold and the axis of the lattice forming surface 11b (symmetrical shape of rotation) and the outer shape 11c of the mold are processed with a coaxial degree of 0.5 μm or less, so that the ring The hole at the center of the mold and the grid forming surface with respect to the inner surface are set with a maximum axial misalignment of about 5.5 μm. Here, a required amount of the ultraviolet curable resin 14 is dropped on the mold 11 using a resin supply device (not shown). (FIG. 2 (b)) Next, as shown in FIG. 2 (c), the glass substrate is fitted into the ring and brought into contact with the resin 14, and then the ultraviolet curable resin 14 is cured by irradiation with ultraviolet rays. Here, the resin thickness is determined by the glass substrate coming into contact with the outer peripheral projection 11d of the mold. The glass substrate 15 on which the resin was molded was released by an ejector mechanism (not shown). (FIG. 2 (d)) Since the outer shape of the glass substrate was about 30 μm smaller than the inner surface of the ring, the resin lattice surface 16b and the protrusion 16a at the center of the resin formed on the outer shape of the glass were 20. It is formed with an axis deviation of about 5 μm. Next, as shown in FIG. 2E, the mold is replaced with a mold 17 for forming the second layer, and a required amount of ultraviolet curable resin 18 is dropped onto the mold 17 using a resin supply device (not shown). This second layer mold is also processed slightly smaller than the inner surface of the ring, and the clearance is 10 μm. In addition, since the axis of the hole portion 17a having a width of 30 μm and the lattice forming surface 17b formed in the center portion of the die and the outer shape 17c of the die are processed with a coaxiality of 0.5 μm or less, the center of the die is in relation to the inner surface of the ring. The hole portion and the grid forming surface are set with a maximum axial misalignment of about 5.5 m. Next, the glass substrate on which the first layer is formed is fitted into the ring. (FIG. 2 (f)) In this state, an image recognition device (not shown) is used to detect the misalignment between the hole 17a at the center of the mold and the protrusion 16a at the center of the resin formed during the first layer molding, and handling (not shown) The position was adjusted using the mechanism, and the positional deviation between the hole 17a and the protrusion 16a was reduced to 1 μm or less, and then contacted with the resin 18 to fit the hole 17a in the mold center and the protrusion 16a in the first resin center. Thereafter, the resin 18 was cured by irradiating ultraviolet rays. (FIG. 2 (g)) Here, the resin thickness is determined by the glass substrate coming into contact with the outer peripheral projection 17d of the mold. The glass substrate having a protrusion 19a having a width of 30 μm in the center and molded with resin was released by an ejector mechanism (not shown). The formed laminated diffraction grating 19 was measured to have a positional deviation between the grating surface 16a of the first layer and the grating surface 20a of the second layer and found to be 1 μm or less. It was 1% or less, and there was no performance deterioration due to the hole at the center of the resin.

  As described above, the first layer and the second layer are formed by providing a hole or a protrusion in the molded first layer resin and fitting the protrusion or the hole provided in the second layer mold. The position of the lattice plane of the layer can be adjusted with a deviation of 1 μm or less. In this embodiment, the mold and the first layer resin are desirably mated, but the second layer resin is cured while maintaining the position after the position adjustment without mating. The same effect can be obtained. In addition, although the embodiment has been described with respect to the lamination of the diffraction grating surface on the flat substrate, the present invention is not limited to the flat surface but can be applied to the formation of the grating surface on the spherical surface.

Schematic which shows the composite type | mold diffractive optical element in a 1st Example, and its manufacturing process. Schematic which shows the composite type | mold diffractive optical element in 2nd Example, and its manufacturing process. 1 is a schematic diagram of a laminated diffractive optical element targeted in the present application. FIG.

Explanation of symbols

1, 7, 11, 17 type 2, 12, 22 glass substrate 3, 13 ring 4, 8, 14, 18 UV curable resin
5, 15 Glass molded with first layer resin 6, 10, 16, 20, 23, 24 Molded and cured resin 9, 19, 21 Multilayer diffractive optical element

Claims (4)

  This process forms a light energy curable resin having a required lattice shape on a substrate by releasing the shape after curing the shape by transferring the shape of the light energy curable resin using a mold on which a lattice is formed, light irradiation, and this process. In the diffractive optical element in which the light energy curable resin is laminated by repeating the above, a protrusion or hole having a width of 30 μm or less is provided at the center of the resin part.   In the step of laminating the composite diffractive optical element according to claim 1, in a state in which the protrusion or hole provided at the center of the optical axis of the diffraction grating surface of the mold is fitted to the hole or protrusion of the resin A method for producing a composite optical element, comprising curing a light energy curable resin.   3. The manufacturing method according to claim 2, wherein the center of the optical axis of the diffraction grating surface of the mold coincides with the axis of the outer diameter of the mold, and the base and the first layer forming mold and base And a method for producing a composite diffractive optical element, wherein the second layer grating forming die is fitted and positioned by an outer diameter.   3. The method according to claim 2, wherein the projection or hole provided in the mold is performed by using position recognition by image processing for alignment of the resin hole or projection. A method for manufacturing an optical element.

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