JP2006123114A - Polishing tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing tool capable of uniform polishing by following after an aspheric surface, when a polishing surface of an optical element is the aspheric surface. <P>SOLUTION: A polishing material 2 is composed of a pattern body 1 for imitating a member for pressing to the optical element 5 from a polishing object surface, that is, the aspheric surface 5F of the optical element 5. This pattern body 1 is composed of an elastic material having proper hardness represented by, for example, a silicon rubber material, and has both of the function of following after the aspheric surface 5F of the optical element 5 and the function of making an aspheric surface shape of the elastic material on a polishing surface of the polishing material 2, that is, polishing cloth. a shock absorbing material 3 has the function of adjusting hardness of the pattern body 1 being the eleastic material. A holding frame 4 of a metal mold integrally holds these polishing tools KD. The holding frame 4 is composed of, for example, stainless steel and an aluminum material, and surely holds the pattern body 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polishing tool for accurately polishing an optical element whose surface to be polished is an aspherical surface.

Normally, in polishing of this type of optical element, the optical element to be polished is fixedly installed on the machine base of the polishing apparatus, and an abrasive (for example, a polishing cloth) is surface-bonded to the aspherical surface of this optical element, and the polishing is performed. The material is moved (reciprocated) with respect to the optical element while being pressed from above with a constant pressure via a pressing member or the like, and polished. As a polishing material in such a polishing tool, a thin polishing material (cloth) of about 1 millimeter that is directly bonded to an aspherical surface or a polishing sheet of several tens of microns is used, and an aspherical surface of an optical element is used as a pressing member. Compared to this, a small component or a tool constituting a large device is employed. In such a polishing tool, it is important how accurately the abrasive is aligned with the aspherical surface, and various methods have been proposed (see, for example, Patent Document 1). As the pressing member and the pressing device, a small member smaller than the aspherical size of the optical element is employed. For example, there is a method in which a mold body having a size of the entire aspherical surface is pressed (molded) using, for example, a mold, and polished using this mold body, or a method of manufacturing by machining.
JP 2002-307280 A

The tools according to the two processing methods described above have the following problems. That is, it is difficult to mold a polishing tool that uses a molded product of a mold as a mold, or has a large difference in thickness of the mold or a non-circular outer shape, and has various limitations. This has a special circumstance that the aspherical surface of the optical element is formed by an 8th order equation or the like, and there is a limit in terms of accuracy in press working or the like. On the other hand, when a die body is manufactured by machining by grinding or grinding, it is an aspherical body having a complicated shape by an 8th-order equation, and therefore a tool having the same size as that for polishing a flat surface or a spherical shape is used. Polishing significantly deteriorates the shape of the surface to be polished. Therefore, in general, partial polishing is performed using a tool smaller than the size of the optical element on the surface to be polished, and the entire surface is polished by connecting the polishing. However, in this method, the joining portion tends to be a discontinuous surface, which adversely affects the optical performance.
The present invention provides a polishing tool that solves such problems.

In order to solve the above-described problems, the polishing tool provided by the present invention provides an abrasive that is bonded to the aspheric surface with respect to an optical element whose surface to be polished is an aspheric surface, and the abrasive is aspherical. In a polishing tool having a pressing member to be pressed and polishing the optical element by moving the pressing member relative to the optical element, the pressing member is formed of a mold imitating the aspherical surface. is there. Therefore, the polishing tool is approximately the same size as the optical element, and can polish the entire aspheric surface uniformly and accurately. Further, according to the present invention, the mold body is made of an elastic material, and the abrasive can be adapted to an aspherical surface.
Furthermore, according to the present invention, a cushioning material is interposed between the abrasive and the mold body, and a finer familiarity is realized.

  By using an elastic material, the contact surface of the abrasive with the optical element fits into the aspheric surface, and a highly smooth aspheric surface can be realized. Further, the entire surface can be evenly polished, and an aspherical surface can be realized while maintaining the aspherical shape created by machining.

  A feature of the present invention resides in that a member that presses an abrasive against an optical element is constituted by a mold body imitating the polished surface of the optical element, that is, an aspherical surface, and this mold body is constituted by an elastic material. Thus, a polishing surface that is most familiar to the surface to be polished can be realized as a polishing tool.

The features of the present invention will be described below with reference to FIGS.
FIG. 1 is a longitudinal sectional view showing a state in which a simulated mold body 1 is held by a mold holding frame 4, and a lower surface 1 F of the mold body 1 has a shape close to an aspheric surface 5 F of an optical element 5. ing. In the illustrated example, a material such as a cushioning material 3 such as a urethane pad is attached to a surface 1F on which the mold body 1 presses the aspherical surface 5F, and an abrasive 2 (specifically, a polishing cloth) is further provided below the cushioning material 3. It is pasted.

  The mold 1 is made of an elastic material having an appropriate hardness represented by, for example, a silicon rubber material, and has a function that follows the aspheric surface 5F of the optical element 5 and a polishing surface of the polishing material 2 (that is, a polishing cloth). It has both the function of creating an aspherical shape of elastic material. The cushioning material 3 has a function of adjusting the hardness of the mold 1 that is an elastic material. Each element of these polishing tools is integrally held by a holding frame 4 of the mold. The holding frame 4 is made of, for example, stainless steel or aluminum material, and holds the mold body 1 securely. Polishing is performed in the state shown in FIG. 2 by the polishing tool KD having such a configuration. The entire polishing tool KD is surface bonded to the entire upper surface of the optical element 5. In this case, the entire weight of the holding frame 4 and the mold 1 acts on the optical element 5, and the abrasive 2 is pressed against the aspherical surface 5F.

  Usually, the optical element 5 is fixedly installed on the machine base 6 of the polishing apparatus shown in FIG. Then, the polishing tool KD is placed above the optical element 5. Specifically, the lower end of the kanzashi 7 is locked to the upper center portion of the holding frame 4, and the load of the holding body 8 that holds the kanzashi 7 acts on the polishing tool KD. One end of a link 9 for giving a moving motion is connected to the holding body 8, and the other end of the link 9 is connected to one end side of a reciprocating plate 10 whose reciprocating motion is restricted by a guide rod 11. . Further, the other end of the reciprocating plate 10 is connected to the other end of a crank 12 connected to a pin 14 that is displaced from a rotating plate 13 that is rotated by a motor 15. With the above configuration, the link 9 reciprocates in the longitudinal direction by the rotation of the motor 15. The polishing tool KD is usually given a reciprocating movement of about several centimeters depending on the shape of the surface to be polished. Further, a mechanism (not shown) for displacing the optical element 5 little by little in the direction perpendicular to the reciprocating motion direction for each reciprocating motion is installed.

  The optical element 5 is polished by such a polishing apparatus. As described above, in the polishing tool KD, the mold holding frame 4 and the mold body 1 have a constant weight and press the abrasive (cloth) 2 against the optical element 5 by itself. The mold body 1 presses the optical element 5 even with the weight of the body 8. Therefore, the mold body 1, the buffer material 3, and the polishing material 2 are deformed so as to follow the aspherical surface 5F of the optical element 5. In this case, since the mold body 1 has a shape close to an aspherical shape, the amount of deformation is small. Therefore, if the momentum in the left-right direction or the vertical direction is adjusted in consideration of the aspherical shape of the optical element 5 and the deformed shape of the mold body 1, the abrasive (cloth) 2 and the optical element 5 are always used during polishing. The aspherical surface 5F in the entire area contacts, and uniform polishing can be realized without impairing the shape.

  The characteristics of the polishing tool KD provided by the present invention are as described in detail above, but the present invention is not limited to the above and illustrated examples, and includes all embodiments including the gist of the present invention. For example, in the illustrated example, the mold body 1 is held by the metallic holding frame 4 and the Kanzashi 7 is locked to the holding frame 4, but the holding frame 4 is omitted and the mold 1 is engaged with the Kanzashi 7. It is also possible to adopt a method in which a stop recess is formed and the Kanzashi 7 is directly locked to the mold body 1 and moved. Normally, the optical element 5 is fixedly installed on the machine base 6 and the mold 1 is moved. However, the mold 1 is fixedly installed and the optical element 5 is mechanically moved. You can also Furthermore, the material of the mold 1 is not limited to the above, and the material of the buffer material 3 is not limited to the above material.

It is a figure which cuts and shows the polish tool of the present invention longitudinally. It is an example which shows the grinding | polishing state by the grinding | polishing tool of this invention. It is a figure which shows an example of the grinding | polishing apparatus which attached the grinding | polishing tool of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Type body 1F surface 2 Abrasive material 3 Buffer material 4 Holding frame 5 Optical element 5F Aspherical surface 6 Machine stand 7 Kanzashi 8 Holding body 9 Link 10 Reciprocating plate 11 Guide rod 12 Crank 13 Rotary disk 14 Pin 15 Motor KD Polishing tool

Claims (5)

  For an optical element whose surface to be polished is an aspherical surface, the optical element has an abrasive that is bonded to the aspherical surface, and a pressing member that presses the abrasive against the aspherical surface. A polishing tool for polishing an optical element by moving the polishing element according to claim 1, wherein the pressing member is formed of a mold imitating the aspherical surface.   2. The polishing tool according to claim 1, wherein the mold is made of an elastic material.   3. The polishing tool according to claim 2, wherein the mold body is made of a silicon rubber material.   The polishing tool according to claim 1, wherein a buffer material is interposed between the mold body and the abrasive. The polishing tool according to claim 4, wherein the cushioning material is formed of a urethane pad.

Images