JPWO2016051851A1 - Lens, lens manufacturing method, and projection apparatus - Google Patents

Abstract

A lens having a non-circular shape formed by cutting a circle along at least one secant line in the optical axis direction and having an end surface extending along the secant line L. The end surface includes a thin region and an extending direction of the end surface A thick region adjacent to both sides of the thin region, and each of the thick regions is provided with at least one pressed portion except for an edge along the front and back surfaces of the lens. .

Description

  The present invention relates to a lens, a lens manufacturing method, and a projection apparatus.

  The lens described in Patent Document 1 is a biconvex lens formed in a substantially rectangular shape when viewed in the optical axis direction, and the thickness of each part of the end surface along the longitudinal direction is thick at the center and toward both ends in the longitudinal direction. The end surface is monotonously thin, and a convex portion or a concave portion substantially similar to the contour of the end surface is provided on the end surface.

  And the manufacturing method of the lens described in patent document 1 manufactures the said lens by injection molding of resin, and the type | mold which shape | molds said convex shape part or a concave shape part is made into a movable compression piece. In the injection molding, the convex portion or the concave portion is compressed by the compression piece. Thereby, it is possible to suppress the difference in volume shrinkage due to the thickness deviation and to improve the shape accuracy of the lens surface.

Japanese Laid-Open Patent Publication No. 10-133004

  The lens described in Patent Document 1 is a biconvex lens having a relatively simple shape, but in recent years, in order to improve the optical performance of the lens, the lens surface is formed in a relatively complicated shape such as an aspherical shape. Tend to be.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to improve the shape accuracy of a lens having a lens surface formed in an aspherical shape.

  The lens of one embodiment of the present invention is a lens that is formed in a non-circular shape formed by cutting a circle along at least one secant line in the optical axis direction, and has an end surface extending along the secant line, and the end surface is A thin region, and a thick region adjacent to both sides of the thin region in the extending direction of the end surface, and an edge along the front and back surfaces of the lens is provided in each of the thick regions. Except for this, at least one pressed part is provided.

  According to another aspect of the present invention, there is provided a lens manufacturing method that emits a lens having a non-circular shape formed by cutting a circle along at least one secant line in the optical axis direction and having an end surface extending along the secant line. A method of manufacturing a lens manufactured by molding, wherein the end surface includes a thin region and a thick region adjacent to both sides of the thin region in the extending direction of the end surface, and injection molding. Sometimes, in each of the thick regions, at least a portion of the thick region is pressed except for the edges along the front and back surfaces of the lens.

  In addition, a projection device of one embodiment of the present invention includes at least one lens.

  According to the present invention, it is possible to increase the shape accuracy of a lens whose lens surface is formed in an aspherical shape.

(A), (B), (C) is a figure which shows the structure of an example of the lens for describing embodiment of this invention. It is a figure which shows the structure of the end surface of the lens of FIG. 1 (A), (B), (C). It is a figure which shows the structure of the modification of the end surface of FIG. It is a figure which shows the structure of the other modification of the end surface of FIG. It is a figure which shows the structure of an example of the injection mold used for manufacture of the lens of FIG. 1 (A), (B), (C). (A), (B) is a figure which shows the manufacturing method of the lens using the injection mold of FIG. It is a figure which shows the structure of the other example of the lens for describing embodiment of this invention.

  FIGS. 1A, 1B, and 1C show a configuration of an example of a lens for explaining an embodiment of the present invention. 1A is a plan view of the lens, FIG. 1B is a front view of the lens, and FIG. 1C is a side view of the lens.

  A lens 1 shown in FIGS. 1A, 1 </ b> B, and 1 </ b> C has a non-circular shape formed by cutting a circle along a dividing line L as viewed in the optical axis direction, and has an end surface 2 extending along the dividing line L. Have. The secant L is a straight line that intersects the circumference at two points. In the illustrated example, the lens 1 is formed in a non-circular shape cut by one dividing line L. However, the lens 1 is cut by two or more dividing lines such as two dividing lines that are symmetric with respect to the optical axis. It may be formed in a non-circular shape.

  The end surface 2 includes a thin region 3 and thick regions 4 and 5 that are adjacent to both sides of the thin region 3 in the extending direction of the end surface 2. In the illustrated example, one optical surface 6 of the lens 1 is formed in a substantially symmetrical convex curved surface with a surface S including the optical axis and perpendicular to the end surface 2 as a boundary, and the other optical surface 7 is approximately defined with the surface S as a boundary. It is formed in a symmetrical concave curved surface, the thin region 3 intersects the surface S, is formed substantially symmetrically with respect to the surface S, and the thick regions 4 and 5 are also substantially symmetrical across the thin region 3. Is formed.

  The boundary between the thin region 3 and the thick regions 4 and 5 is an offset line 6a along one optical surface 6 when the contour of the end surface 2 is offset inward by a distance of ½ or more of the minimum thickness of the thin region 3. And a line segment passing through the intersection with the offset line 7a along the other optical surface 7.

  Note that the minimum thickness of the thin region 3 refers to the value of the minimum diameter of the circle C1 inscribed in the contour line along the one optical surface 6 and the contour line along the other optical surface 7 of the lens 1, The inside of the circle to be given is a part that gives the minimum thickness of the thin region 3.

  FIG. 2 shows the configuration of the end face 2.

  Each of the thick regions 4 and 5 is provided with at least one pressed portion 9 except for the edge portion 8 along one optical surface 6 and the other optical surface 7 of the lens 1. Although the details will be described later, the pressed portion 9 is a portion that is pressed in the process of injection molding of the lens 1 formed by resin injection molding.

  In the injection molding of the lens 1, the resin is cooled and solidified from the surface side in contact with the mold, and the cooling rate of each part is related to the thickness of each part of the lens 1. A state in which fluidity is maintained without being inhibited by the thinned region 3 or the edge 8 that solidifies in advance by providing the pressed portion 9 in the region other than the edge 8 of each of the thick regions 4 and 5. Can be pressed. From this point of view, it is preferable that the edge 8 has a thickness that is 1/2 or more of the minimum thickness Tmin of the thin region 3.

  In the example shown in the figure, the entire area excluding the edge 8 from each of the thick areas 4 and 5 is the pressed part 9, but the pressed part 9 is not limited to the example shown in FIG. Absent. For example, as shown in FIG. 3, it may be provided in a part of the region excluding the edge 8 from each of the thick regions 4 and 5, and as shown in FIG. A plurality may be provided dispersed in the area excluding the edge 8 from each. Further, the pressed portion 9 may be formed in a concave shape on the end surface 2, may be formed in a convex shape on the end surface 2, or may be formed substantially flush with the end surface 2.

  Here, it is preferable that at least a part of the pressed portion 9 is included in a portion that gives the maximum thickness of each of the thick regions 4 and 5. By pressing the portion that gives the maximum thickness of each of the thick regions 4 and 5, it is possible to press the resin in a state where the fluidity is maintained more reliably in the process of injection molding of the lens 1.

  Note that the maximum thickness of the thick regions 4 and 5 refers to the value of the maximum diameter of the circle C2 inscribed in the contour line along one optical surface 6 of the lens 1 and the contour line along the other optical surface 7; The inside of the circle that gives the maximum diameter is the part that gives the maximum thickness of the thick regions 4 and 5.

  FIG. 5 shows a configuration of an example of an injection mold used for manufacturing the lens 1.

  An injection mold 10 shown in FIG. 5 includes an upper mold 11, a lower mold 12, and a nest 13.

  The upper mold 11 is provided with a molding surface 14 for molding one optical surface 6 of the lens 1, and the lower mold 12 is provided with a molding surface 15 for molding the other optical surface 7 of the lens 1. The nest 13 is provided with a molding surface 16 for molding the end surface 2 of the lens 1.

  The insert 13 includes an upper die 11, a lower die 12, and a compression piece 18 that presses resin filled in a cavity 17 surrounded by the insert 13. The compression piece 18 is supported by the insert 13 so as to be able to advance and retreat in a direction substantially orthogonal to the mold opening direction of the upper mold 11 and the lower mold 12, and the front end surface 19 of the compression piece 18 is exposed to the molding surface 16. As the compression piece 18 advances, the resin filled in the cavity 17 is appropriately compressed. The insert 13 is also supported by the upper mold 11 and the lower mold 12 so as to be movable in the advancing and retreating direction of the compression piece 18.

  The compression piece 18 forms a pressed portion 9 provided in each of the thick areas 4 and 5 of the end surface 2 of the lens 1, and although not shown, the nest 13 has a cover of the thick area 4. At least one compression piece 18 corresponding to the pressing portion 9 and at least one compression piece 18 corresponding to the pressed portion 9 in the thick region 5 are provided.

  The molding surface 16 and the tip surface 19 of the compression piece 18 may be roughened. According to this, the pressed surface 9 molded by the end surface 2 of the lens 1 molded by the molded surface 16 and the distal end surface 19 of the compression piece 18 can be roughened. Reflection of the generated light can be suppressed.

  Further, the configuration of the injection mold 10 described above is an example, and a molding surface 16 may be provided on the lower mold 12, and the compression piece 18 may be supported by the lower mold 12 so as to advance and retreat. Alternatively, the molding surface 16 may be provided on the upper die 11 and the compression piece 18 may be supported by the upper die 11 so as to be able to advance and retreat.

  6A and 6B show a method for manufacturing the lens 1 using the injection mold 10.

  As shown in FIG. 6A, the resin M is filled from the gate 20 into the cavity 17. The gate 20 is provided on the surface of the cavity 17 except for the molding surfaces 14 and 15 for molding the optical surfaces 6 and 7 of the lens 1 and the molding surface 16 for molding the end surface 2 of the lens 1, respectively. Then, it is provided on the outer peripheral edge of the cavity 17 on the opposite side to the molding surface 16.

  After the cavity 17 is filled with the resin M, as shown in FIG. 6B, before the resin M is cooled and solidified, the compression piece 18 is gradually advanced to compress the resin M, and the resin M accompanying the cooling and solidification. The pressure shrinkage is compensated for. Thereby, the occurrence of sink marks is suppressed in the lens 1 formed by solidifying the resin M, and the shape accuracy of the lens 1 can be increased.

  The sink marks in the lens 1 occur more prominently in the thicker part and in the part farther from the gate 20, and the compression piece is formed so as to form the pressed portion 9 in each of the thick areas 4 and 5 of the end surface 2 of the lens 1. By pressing the resin M with 18, the occurrence of sink marks can be effectively suppressed.

  As described above, the resin M is cooled and solidified from the surface side in contact with the mold, and the cooling rate of each part is related to the thickness of each part, but in the areas other than the edge parts 8 of the thick areas 4 and 5. By pressing the resin M with the compression piece 18 so as to provide the pressed portion 9, the resin M in a state in which the fluidity is maintained without being obstructed by the thinned region 3 or the edge portion 8 that solidifies in advance. Can be pressed.

  In the injection molding of the lens 1 in which the thick regions 4 and 5 are formed substantially symmetrically across the thin region 3, the pressed portion 9 of the thick region 4 and the pressed portion 9 of the thick region 5 are also thin. They are provided approximately symmetrically across the region 3. According to this, the pressing of the resin M by the compression piece 18 corresponding to the pressed part 9 of the thick region 4 and the pressing of the resin M by the compression piece 18 corresponding to the pressed part 9 of the thick region 5 are balanced. The occurrence of sink marks can be more effectively suppressed.

  In the filling process of the resin M shown in FIG. 6A, for example, when the front end surface 19 of the compression piece 18 is substantially flush with the molding surface 16, each of the thick regions 4 and 5 The pressed portion 9 is formed in a concave shape on the end surface 2, and the pressed portion 9 is formed substantially flush with the end surface 2 or convex so that the front end surface 19 of the compression piece 18 is retracted from the molding surface 16. Is done.

  When removing the lens 1 from the injection mold 10, the compression piece 18 is retracted when the pressed portion 9 is formed in a concave shape, and the insert 13 is retracted when the pressed portion 9 is formed in a convex shape. You can do it.

  As an example of the optical device including the lens 1 described above, in a projection apparatus further including an image display element such as an LCD (liquid crystal display) panel, the shape accuracy of the lens 1 is high. Image quality can be improved.

  Although the present invention has been described above by taking the lens 1 as an example, the configuration of the lens 1 is an exemplification, and appropriate modifications and changes can be made without departing from the scope of the present invention.

  For example, in the lens 101 shown in FIG. 7, both of the optical surfaces 106 and 107 are formed as concave surfaces that are substantially symmetrical with respect to a surface S that includes the optical axis and is perpendicular to the end surface 102. , The thin region 103 intersecting the surface S, and the thick regions 104 and 105 adjacent to both sides of the thin region 103 in the extending direction of the end surface 102. A pressed portion 109 is provided in a region excluding the edge portion 108 of each of the thick regions 104 and 105. By pressing the resin so as to form the pressed portion 109 by the injection molding of the lens 101, sinking is performed. Can be suppressed, and the shape accuracy of the lens 101 can be increased.

  As described above, the lens disclosed in the present specification is a lens having a non-circular shape formed by cutting a circle along at least one secant line in the optical axis direction and having an end surface extending along the secant line. The end face has a thin area, and thick areas adjacent to both sides of the thin area in the extending direction of the end face, and each of the thick areas includes a surface of the lens and Except for the edge part along a back surface, at least 1 to-be-pressed part is provided.

  In the lens disclosed in the present specification, at least a part of the pressed portion is included in a portion that gives the maximum thickness of the thick region.

  Further, in the lens disclosed in the present specification, the edge portion has a thickness that is 1/2 or more of the minimum thickness of the thin region.

  Further, in the lens disclosed in the present specification, the thick region adjacent to both sides of the thin region is symmetric with respect to the thin region, and the pressed portion provided in each of the thick regions. The part is also symmetric with respect to the thin region.

  Further, in the lens disclosed in this specification, the pressed portion is roughened.

  Further, the lens manufacturing method disclosed in the present specification is a lens having a non-circular shape formed by cutting a circle along at least one secant line in the optical axis direction and having an end surface extending along the secant line. A method of manufacturing a lens manufactured by injection molding, wherein the end surface includes a thin region and a thick region adjacent to both sides of the thin region in the extending direction of the end surface, and injection At the time of molding, in each of the thick regions, at least a part of the thick region is pressed except for edge portions along the front and back surfaces of the lens.

  Further, in the lens manufacturing method disclosed in the present specification, at least a part of a portion that gives the maximum thickness of the thick region is pressed.

  Further, in the lens manufacturing method disclosed in the present specification, the thickness of the edge portion is set to be 1/2 or more of the minimum thickness of the thin region.

  Further, in the method for manufacturing a lens disclosed in the present specification, the thick regions adjacent to both sides of the thin region are symmetrical with respect to the thin region, and each of the thick regions is Then, press symmetrically across the thin region.

  Further, in the lens manufacturing method disclosed in this specification, the thick region is roughened by pressing the thick region.

  Moreover, the projection apparatus disclosed in this specification has at least one lens.

  The present invention is particularly convenient and effective when applied to a lens or the like.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on September 30, 2014 (Japanese Patent Application No. 2014-200078), the contents of which are incorporated herein by reference.

DESCRIPTION OF SYMBOLS 1 Lens 2 End surface 3 Thin area | region 5 Thick area | region 6 Optical surface (surface)
7 Optical surface (back)
8 Edge 9 Pressed part L Split line

Claims (11)

A lens having a non-circular shape formed by cutting a circle along at least one secant in the optical axis direction and having an end surface extending along the secant,
The end surface has a thin region, and a thick region adjacent to both sides of the thin region in the extending direction of the end surface,
A lens in which at least one pressed portion is provided in each of the thick regions except for an edge portion along a front surface and a back surface of the lens. The lens according to claim 1,
At least a part of the pressed portion is a lens included in a portion that gives the maximum thickness of the thick region. The lens according to claim 1 or 2,
The edge is a lens having a thickness of 1/2 or more of the minimum thickness of the thin region. The lens according to any one of claims 1 to 3,
The thick region adjacent to both sides of the thin region is symmetric with respect to the thin region,
The pressed part provided in each of the thick regions is also a lens that is symmetrical with respect to the thin region. The lens according to any one of claims 1 to 4,
The pressed portion is a lens having a roughened surface. A lens manufacturing method for manufacturing a lens having a non-circular shape formed by cutting a circle along at least one secant in the optical axis direction and having an end surface extending along the secant, by injection molding,
The end face has a thin area, and a thick area adjacent to both sides of the thin area in the extending direction of the end face,
A method of manufacturing a lens, wherein at least a part of the thick region is pressed in each of the thick regions at the time of injection molding, except for edges along the front and back surfaces of the lens. A method of manufacturing a lens according to claim 6,
A method of manufacturing a lens that presses at least a part of a portion that gives the maximum thickness of the thick region. A method for manufacturing a lens according to claim 6 or 7,
A method for manufacturing a lens, wherein the thickness of the edge is set to a thickness equal to or greater than ½ of the minimum thickness of the thin region. A method for manufacturing a lens according to any one of claims 6 to 8,
The thick region adjacent to both sides of the thin region is symmetrical with respect to the thin region,
A method for manufacturing a lens, wherein each of the thick regions is pressed symmetrically across the thin region. A method for manufacturing a lens according to any one of claims 6 to 9,
A method for manufacturing a lens in which the thick region is roughened by pressing the thick region.   A projection apparatus comprising at least one lens according to any one of claims 1 to 5.

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