JPH02154203A - Manufacture of prism - Google Patents

Abstract

PURPOSE:To shorten a machining process and to improve the performance by providing a process wherein both main surfaces are cut to form a quadrangular prism body and a process wherein a surface almost perpendicular to the reflecting surface of the quadrangular prism body is cut to form a right-angled isosceles triangular prism body having the reflecting surface as its base. CONSTITUTION:Multi-layered reflecting films are vapor-deposited on both surfaces of ground glass 1b to form reflecting surfaces 9a and 9b, which are adhered and fixed to a glass base and cut to specific size by multislicing into triangular prism bodies 10. The triangular prism bodies 10 are adhered and fixed in grooves 13a of a cutting jig 13 while having the reflecting surfaces 9a and 9b held vertically and the multiblade is set at 45 deg. to the reflecting surface to perform a cutting process. The jig is rotated by a specific angle (90 deg.) to perform a cutting process at 45 deg. similarly. Thus, prisms are formed by the cutting. Consequently, the man-hours of the machining of the right-angled isosceles triangular prism bodies is reduced to half, the prisms are machined in quantities in a short time by multislicing, and the performance of the reflecting surfaces is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing a prism, and particularly to a method of manufacturing a prism mirror used in a pickup head or the like.

(Prior art) In general, a method for manufacturing a right isosceles triangular prism as shown in FIG.
o10 (1987), p. 623. Third
Figures (a) to (g) outline the process.

The press-shaped triangular prism glass material 31 in FIG. 3(a) is
In the same figure (b), the first jig 3 has a groove at an angle of 90 degrees.
A glass material 31 is bonded and fixed to 2. Next, this glass material is processed into a flat surface by surface grinding (rough processing and precision processing),
It is then polished to a mirror finish. Next, cut the two prism materials 33.
Divide into 34 parts. In the same figure (C), this divided prism material is glued and fixed to a second jig 35 having a groove portion at an angle of 451 degrees with the above-mentioned cut surface 36 facing upward. Next, this second surface is also subjected to surface grinding and polishing in the same manner as described above.

The figure (d) shows a third jig 37 having a groove at an angle of 90 degrees.
Glue and fix the slope portion 3B upward. Next, this surface is also subjected to surface grinding and polishing to obtain the mirror surface of the third surface. Figure (e) shows the polishing process, for example (d).
) is ground on the rotating surface plate 3 of the polishing device.
Polishing is performed by applying an abrasive such as cerium oxide to a polishing pad 40 made of polyurethane, for example, which is adhered to the pad 9 .

Although a triangular prism can be obtained by the above method, a right isosceles triangle can be manufactured by processing only the sloped portion into a mirror surface by limiting the surface grinding to the surface grinding of the outside of the sloped portion.

Figure (f') shows a triangular prism with a reflective film deposited on the inclined surface 41, and Figure (g) shows a triangular prism that is glued and fixed to a cutting jig 42, and then cut into a single prism using a cutting wheel. 43 performs cutting. After that, it is peeled off, washed, etc., and the Brism is completed.

(Problems to be Solved by the Invention) However, the conventional technology has three main problems. The first problem is that the material is pressed into the shape of a prism. (requires a process of heating the glass material, semi-melting it, and pressing it). This makes it difficult to reduce material costs. The second problem is that the edges of the prism tend to sag during polishing, making it difficult to finish the entire surface to a highly flat surface. The part that becomes the outside of the prism when the polishing surface of the prism is pressed against the polishing pad, i.e.
The edges are the most susceptible to abrasive agents and will become sagged. The third problem is that there are many processing steps for the prism. Adhesion, polishing, and peeling.

It is necessary to repeat cleaning etc. several times, which is an impediment to cost reduction.

The problems listed above are all related to the use of triangular shaped prisms as the material.

In order to solve these problems, the present invention uses flat glass, which is an inexpensive material, shortens the processing process without repeating work, uses a double-sided polishing method for the reflective surface that does not cause edge sag, and further reduces material loss. It is an object of the present invention to provide a method of manufacturing a prism that allows for a reduction in the number of prisms.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides a process F7 for mirror-finishing both main surfaces of a flat plate for a prism.
a step of depositing a reflective film on both main surfaces to form a reflective surface; and a step of cutting both main surfaces to form a square prism.
The method is characterized by comprising the step of: forming a right-angled isosceles triangular prism with the reflective surface as a base by cutting a surface in a direction substantially perpendicular to the reflective surface of the quadrangular prism. . (Function) The material of the prism is flat glass. Flat glass is processed into a mirror surface on both sides using a double-sided polisher.

The thickness of the glass is taken as the square root of the length of the right-angled side of the prism. Next, after cleaning, reflective films are deposited on both surfaces to form reflective surfaces. These reflective surfaces on both sides become the slopes of the prism.

Next, one side of the reflective surface is fixed using a vacuum chuck or adhesive method, and the prism is cut to size in the width direction using a cutting wheel to form a square prism. Next, glue and fix it to the cutting jig with the reflective surface facing vertically and horizontally. Set the cutting wheel at a 45 degree angle to the reflective surface and cut. Next, set the jig 9
Rotate 0 degrees and cut again at a 45 degree angle. The cut product is peeled off from the jig and washed to obtain the prism.

The flatness of the prism reflective surface is determined by using a polishing method that provides excellent flatness for the entire flat glass, so there is no sag at all in the area that will become the prism reflective surface.

Furthermore, it has superior flatness compared to conventional products.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 2 is a perspective view of a completed right-angled isosceles triangular prism 20 whose sloped portion serves as a reflective surface 9, and is made of borosilicate glass or the like. The dimensions of the prism are as follows: the dimension of the right angle surface 21 is 6 degrees, the width dimension H is 61111 degrees, and the dimension of the reflective surface is approximately 8 degrees.
The explanation will be based on the size of 4 x 6 mm.

The reflected wavefront aberration (RMS) of the characteristics of the reflective surface is 0.02λ (
λ-780 ns) or less, and the angle accuracy is generally within 10 minutes.

FIGS. 1(a) to (f') show an overview of the steps of the present invention. In FIG. 1(a), the base material 1 is obtained by cutting a commercially available flat glass, and the material used is borosilicate glass or the like. The embodiment shown in FIG. 2 is a rectangular flat glass with a side of 70+u and a thickness of 5.5 mm.
5 points are used. The thickness of the plate is the thickness of the prism (in the prism mentioned above, the right angle side is 6III11, so it is approximately 4.2
The wall thickness is the sum of 4 m+i) plus the wrap allowance.

In the figure (b), both sides of the flat glass 1a are first wrapped. Upper and lower surface plates of double-sided wrapping IIl/C 2.
Parallel and plane processing is performed between 3. The lap pressure is tens of grams/c! The free abrasive grains used are GCJf200.
Use an abrasive such as 0 to 2500. The finished dimensions of the wrapping are the thickness dimensions of the prism.

As mentioned above, the finished dimensions are approximately 4.24 am.

In the same figure (C), both sides are polished to a mirror finish using double-sided polishing 1IllC. Polyurethane polishing pads 8 provided on the upper and lower surface plates 6 and 7 are rotated by the carrier 4 to polish the glass to a mirror finish. Get 1b. The polishing allowance is approximately 20 μm. The abrasive used is generally cerium oxide or the like.

In FIG. 4(d), a multilayer reflective film is deposited on both sides of the polished glass 1b to form reflective surfaces 9a and 9b.

In the same figure (e), the reflecting surfaces 9a and 9b are glued and fixed to a glass base, and cut into a predetermined size using multi-slice Al/C to form a rectangular prism 10. The width of the cutting is that of the prism. Corresponds to the width. In the above example, it is 6fl111. The cutting multi-blade uses a diamond wheel with an abrasive grain size of 600.

In the same figure (r), a square prism 10 is cut into a cutting jig 13 with a reflective surface 9.
; t, 9 are oriented vertically and glued and fixed in the groove 13a of the jig. The multi-blade is set at a 45 degree angle to the reflective surface to perform cutting. Next, set the jig at a predetermined angle (90
degree) and cut at the same NA at a 45 degree angle. The jig 13 has a multi-blade relief groove 13b.

13c is provided. These cuts form prisms, which are then removed from the jig and cleaned.

The reflective surface of the prism has no edges due to polishing, and Z
YGO-MARK2+: Reflected wavefront aberration (RMS)
A value of 0.005λ (λ-780nm) can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the number of processing steps for prisms of right-angled isosceles triangular prisms can be halved, and a large number can be processed in a short time by double-sided polishing and multi-slicing, and the performance of the reflective surface can be improved. can be improved.

[Brief Description of the Drawings] Figures 1(a) to (f) are explanatory diagrams showing one embodiment of the prism manufacturing process of the present invention, and Figure 2 is a perspective view showing a completed product of a right-angled isosceles triangular prism. , Figures 3(a) to (g)
FIG. 1 is an explanatory diagram showing a conventional prism manufacturing process. 1...Substrate 9.9a, 9b...Reflecting surface 20...Right-angled isosceles triangular prism Agent Patent attorney Noriyuki Chika Yudo Kikuo Takehana Figure 1

Claims (1)

[Claims] A step of mirror-finishing both main surfaces of a flat plate for a prism, a step of depositing a reflective film on the both main surfaces to form a reflective surface, and cutting both the main surfaces to form a quadrangular prism. and a step of forming a right-angled isosceles triangular prism whose cross-sectional shape has the reflective surface as its base by cutting a surface substantially perpendicular to the reflective surface of the quadrangular prism. Characteristic prism manufacturing method.