JP2008023758A - Method for manufacturing optical element mold and optical element mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an optical element mold which can accurately produce the optical element mold and the optical element mold. <P>SOLUTION: In a processing method for manufacturing a mold for molding the optical element having a plurality of independent optical function surfaces by processing a workpiece 1A mounted on work employment, a linear groove extending in the X-axis direction is formed in a dummy workpiece 1B fitted to the work employment 50 by using a single crystal diamond bite 42 as a tool to obtain the coordinates of the terminal end of the groove. After that, the provisional center coordinates of the workpiece 1A are obtained from the coordinates of four points in the peripheral part of the workpiece 1A to be processed based on the obtained coordinates. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical element mold manufacturing method and an optical element mold.

  Conventionally, when a lens array mold is manufactured by cutting, there are fly cutting, shaper, and planar processing as processing methods for the base material (workpiece) of the mold. In general, a workpiece is fixed to a work (table) using a screw (see the following patent document).

During the manufacturing of the lens array mold, a recess corresponding to one lens of the lens array mold is formed on the processed surface of the workpiece, the workpiece is removed from the hire, and the recess is formed from the outer periphery of the workpiece. Are measured and the measured value is used for correcting the misalignment of the recess.
JP 11-179601 A

  However, despite the fact that the machining accuracy when manufacturing the mold depends on the positional accuracy between the cutting edge and the workpiece, it is not possible to hire the workpiece with high accuracy due to screw tolerance etc. Because it was difficult, it was difficult to manufacture the mold accurately.

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

  In order to solve the above-mentioned problem, the invention according to claim 1 includes a tool for processing a workpiece, a holding portion for holding the workpiece, a stage for relatively moving the tool and the holding portion, In the manufacturing method of an optical element mold for forming a mold for forming an optical element having an optical functional surface by processing using a processing apparatus having a microscope movable with the tool by moving the stage, A linear groove extending in the X-axis direction is formed in the dummy workpiece using the tool while moving the stage, and the stage position coordinate of the final end of the groove is obtained based on the output from the stage, The X coordinate of the final end of the groove, the Y coordinate of one ridge line of the groove, and the Y coordinate of the other ridge line of the groove are observed using the microscope to obtain the coordinate of the final end of the groove, When processing grooves A first step for obtaining a difference amount from a stage position coordinate of the final end and a coordinate of the final end of the groove observed using the microscope, and an outer peripheral portion of the workpiece to be processed after the first step And calculating the position of the cutting edge of the tool from the mold design data based on the reference coordinates. The second step of obtaining the reference coordinates of the workpiece based on the coordinates of the four points and the difference amount It is characterized by.

  According to a second aspect of the present invention, in the method of manufacturing an optical element mold according to the first aspect, the second step includes a reference coordinate of the workpiece from the coordinates of four points on the outer peripheral portion of the workpiece. A step of performing a plurality of times, and a step of setting the coordinates when the obtained reference coordinates are the same as the reference coordinates two or more times as reference coordinates.

  The invention described in claim 3 is an optical element mold manufactured by the manufacturing method described in claim 1 or 2.

  According to this invention, the optical element mold can be manufactured with high accuracy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  Fig.1 (a) is a side view of the processing apparatus used for use of the manufacturing method of the optical element metal mold | die which concerns on one Embodiment of this invention, FIG.1 (b) is the top view.

  This processing apparatus includes a Z-axis stage 10, a Y-axis stage 20, an X-axis stage 30, and a B-axis stage (stage) 40.

  The machining apparatus of this embodiment is, for example, an NC machining apparatus, and a motor that drives the Z-axis stage 10, the Y-axis stage 20, the X-axis stage 30, and the B-axis stage 40, for example, according to an instruction from an NC controller (not shown). The start / stop of the actuator (not shown) and the rotation speed are controlled.

  The Z-axis stage 10 is disposed on the surface plate 5. The Z-axis stage 10 is movable on the surface plate 5 along the Z-axis stage guide 11 in the Z-axis direction. The position of the Z-axis stage 10 is detected by, for example, an encoder, and the detection result is fed back to the NC controller.

  A work hire (holding portion) 50 is attached to the tip end portion of the spindle unit 15 disposed on the Z-axis stage 10 in the Z-axis direction. When the work hire 50 is caused to move to the main spindle unit 15, the work hiring 50 starts to run relative to the main spindle unit 15 (tilt adjustment with respect to the X, Y, and Z axes).

  The X-axis stage 30 is disposed on the surface plate 5 so as to face the Z-axis stage 10 at a predetermined interval in the Z direction. The X-axis stage 30 is movable on the surface plate 5 in the X-axis direction. The position of the X-axis stage 30 is detected by, for example, an encoder, and the detection result is fed back to the NC controller.

  The Y axis stage 20 is disposed on the X axis stage 30. The Y-axis stage 20 can move in the Y-axis direction (height direction) along the Y-axis stage guide 21. The position of the Y-axis stage 20 is detected by, for example, an encoder, and the detection result is fed back to the NC controller.

  The B-axis stage 40 is disposed on the Y-axis stage 20. The B-axis stage 40 can be rotated around the Y-axis perpendicular to the Z-axis and the X-axis by a B-axis stage motor 41 disposed on the lower surface of the Y-axis stage 20. The rotation angle of the B-axis stage 40 is detected by, for example, an encoder, and the detection result is fed back to the NC controller.

  The B-axis stage 40 is provided with a diamond bit holder 43 that holds a diamond bit (tool) 42. As the diamond tool 42, a single crystal diamond tool is generally used. The single crystal diamond tool has a feature that the outer periphery of the groove 2 and the recess 44a shown in FIGS. 3 and 4 can be formed so as not to generate a flash.

  A processing surface (XY surface) 44 of the workpiece 1A (see FIG. 2) is ground using a diamond tool 42 to form a recess 44a corresponding to the lens shape of the microlens.

  The Y axis stage 20 is provided with a microscope 25. An index is provided in the field of view of the microscope 25. By positioning the X-axis stage 30 and the Y-axis stage 20 so that the center of the index comes to a desired position on the work hire 50, the XY on the work hire 50 is obtained. Find the plane coordinates.

  FIG. 2A is a plan view of an optical element mold according to an embodiment of the present invention, and FIG. 2B is a side view thereof.

  A workpiece 1A and a dummy workpiece (dummy workpiece) 1B which are base materials of the microlens mold (optical element mold) 1 shown in FIG.

  As a material of the workpiece 1A, for example, there is a material obtained by applying Ni-P (electroless nickel plating) to Stabux.

  An example of the material of the dummy workpiece 1B is brass.

  Next, a method for calculating the machining position of the workpiece 1A will be described.

  FIG. 3 is an enlarged plan view of the grooved dummy workpiece, FIG. 4A is an enlarged plan view of the workpiece for explaining a method for obtaining the center coordinates of the workpiece, and FIG. 4B is a workpiece. FIG. 5 is a flowchart for explaining the manufacturing method, and FIG. 5 is an enlarged plan view of the workpiece for explaining the positional relationship between the center position of the substrate and the recess. In FIG. 5, S1 to S11 indicate processing steps.

  First, the workpiece 1A (workpiece) and the dummy workpiece 1B are fixed to the workpiece hire 50 (S1).

  Next, the work hire 50 is attached to the spindle unit 15 of the machining apparatus (S2).

  Thereafter, a linear groove 2 extending in the X-axis direction is formed on the processed surface of the dummy workpiece 1B (see FIG. 2) (S3).

  Next, the position (XY coordinate (stage position coordinate)) of the end of the groove 2 on the machining surface of the dummy workpiece 1B in the tool coordinate system is obtained based on the output value of each encoder, and stored in the memory of the NC controller. (S4).

  Thereafter, the X-axis stage 30 and the Y-axis stage are arranged so that the X coordinate Xe of the final end of the groove 2, the Y coordinate Y1 of one ridge line of the groove, and the other Y coordinate Y2 of the groove 2 are respectively located at the index center of the microscope 25. 20 is driven, and the position at that time is obtained based on the output value of each encoder (see FIG. 3) (S5). At this time, the Y coordinate Yc of the final end is obtained from the Y coordinate Y1 and the Y coordinate Y2 using one equation. Then, a difference amount is obtained based on the coordinates of the final end of the groove 2 in the tool coordinate system and the coordinates (Xe, Yc) observed using the microscope 25, and is stored in the memory of the NC controller.

Yc = (Y1 + Y2) / 2 (1 formula)
Steps S1 to S5 correspond to the first step.

  Next, the coordinates x1, x2, y1, and y2 of the four points on the outer peripheral portion of the workpiece 1A are obtained while observing with the microscope 25 ((see FIG. 4A)) (S6). The center coordinates (KX, KY) of the workpiece 1A are obtained using the equations 2 and 3, and the center coordinates (KX, KY) of the diamond bit 42 are determined based on the difference amount obtained in the previous step (S5). The coordinates (tool coordinates) are converted and stored in the NC controller ((see FIG. 3B)) (S7).

KX = (x1 + x2) / 2 (2 formulas)
KY = (y1 + y2) / 2 (3 formulas)
Thereafter, four points that are the same as or different from the four points on the outer periphery of the workpiece 1A are observed again with a microscope, and the center coordinates (KX, KY) is obtained (S8).

  Next, it is determined whether or not the center coordinates (KX, KY) of the workpiece 1A obtained in step S7 coincide with the center coordinates (KX, KY) of the workpiece 1A obtained in step S8 (S9). ).

  When the center coordinates (KX, KY) of the workpiece 1A obtained in step S7 and the center coordinates (KX, KY) of the workpiece obtained in step S8 do not coincide (NO), the outer peripheral portion of the workpiece 1A The coordinates of the four points are again observed with a microscope, and the center coordinates (KX, KY) of the workpiece 1A are obtained from these coordinates (not shown) in the same manner as in step S8 (S10), and the process returns to step S9. . By these steps S9 and S10, the center coordinates KX and KY can be obtained more accurately.

  When the center coordinates (KX, KY) of the workpiece obtained in step S7 coincide with the center coordinates (KX, KY) of the workpiece obtained in step S8 (YES), the center coordinates (KX, KY) Calculate the machining position of the workpiece 1A (the position of the cutting edge of the diamond tool 42) from the mold design data (the position of the concave portion of the microlens mold is defined as the design value) on the tool coordinates with reference as the reference coordinate. (S11).

  Steps S6 to S11 correspond to the second step.

  Through the above steps, the positional relationship between the diamond tool 42 and the workpiece 1A is determined.

  In the case of a workpiece employer 50 that can fix a plurality of types of microlens molds 1, before attaching the workpiece employer 50 to the machining apparatus, the dimensions between the workpieces 1A are measured in advance, and the measurement results are stored in the memory of the NC controller. Just remember. By using this measurement result, the machining positions of all the workpieces 1A can be obtained.

Thereafter, the workpiece 1A is processed by, for example, the following method.
(1) The diamond bit 42 is simultaneously moved in the X-axis and Z-axis directions according to the radius of curvature of the concave portion of the microlens mold to cut the processed surface 44 of the workpiece 1A.
(2) After cutting the workpiece 1A by a predetermined amount, the workpiece 1A is moved in the Y-axis direction by a predetermined pitch (see FIG. 2A).
(3) Similarly to (1), the diamond cutting tool 42 is simultaneously moved in the X-axis and Z-axis directions to cut the processed surface 44 of the workpiece 1A.

  Thereafter, the microlens mold 1 is created by repeating the steps (1) to (3).

  When the present inventor created a so-called four-eye microlens mold 1 (diameter: 12 mm) having a curvature radius of 2.5 mm of the concave portion 44a by the above processing method, the positioning error was 3 μm or less at the worst (conventional method) (On average, there was a positioning error of about 10 μm).

  According to this embodiment, since it is not necessary to remove the workpiece 1A from the work hire 50 in order to measure dimensions during the manufacturing of the lens array mold, the positional relationship between the diamond tool 42 and the workpiece 1A is increased. It is required for accuracy, and the workpiece 1A can be processed easily and with high accuracy. As a result, each lens array can be manufactured with high accuracy.

FIG. 1A is a side view of a processing apparatus used for carrying out an optical element mold manufacturing method according to an embodiment of the present invention, and FIG. 1B is a plan view thereof. FIG. 2A is a plan view of an optical element mold according to one embodiment of the present invention, and FIG. 2B is a side view thereof. FIG. 3 is an enlarged plan view of a dummy workpiece having a groove formed therein. 4A is an enlarged plan view of a workpiece for explaining a method for obtaining the center coordinates of the mold, and FIG. 4B is a diagram of the workpiece for explaining the positional relationship between the center position of the mold and the microlens. It is an enlarged plan view. FIG. 5 is a flowchart for explaining the processing method.

Explanation of symbols

  1: Micro lens mold (optical element mold), 1A: work piece, 1B: dummy work piece (dummy work), 2: groove, 25: microscope, 40: B axis stage (stage), 42: diamond tool (Tool), 50: Work hire (holding part), x1, x2, y1, y2: coordinates of four points.

Claims (3)

A tool for processing a workpiece, a holding portion for holding the workpiece, a stage for relatively moving the tool and the holding portion, and a microscope movable with the tool by moving the stage In a manufacturing method of an optical element mold for forming a mold for forming an optical element having an optical function surface by processing using a processing apparatus having
A linear groove extending in the X-axis direction is formed in the dummy workpiece using the tool while moving the stage, and the stage position coordinate of the final end of the groove is obtained based on the output from the stage,
Next, the X coordinate of the final end of the groove, the Y coordinate of one ridge line of the groove, and the Y coordinate of the other ridge line of the groove are observed using the microscope, and the coordinate of the final end of the groove is determined. Seeking
A first step of obtaining a difference amount from a stage position coordinate of the final end at the time of processing of the groove and a coordinate of the final end of the groove observed using the microscope;
After the first step, a second step of obtaining reference coordinates of the workpiece based on the coordinates of the four points of the outer peripheral portion of the workpiece to be machined and the difference amount,
A method of manufacturing an optical element mold, wherein the position of a cutting edge of a tool is calculated from mold design data based on the reference coordinates.   In the second step, the step of obtaining the reference coordinates of the workpiece from the coordinates of the four points on the outer periphery of the workpiece is performed a plurality of times, and the obtained reference coordinates are the same two or more times. 2. The method of manufacturing an optical element mold according to claim 1, further comprising a step of using coordinates as reference coordinates.   An optical element mold manufactured by the manufacturing method according to claim 1.

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