JPH06134661A - Holding tool for polishing len of large diameter - Google Patents

Abstract

PURPOSE:To polish a lens uniformly to the peripheral part by providing a clearance between the center part of a holding pan and a pressure-applying cap. CONSTITUTION:The rotational movement of a polishing pan 11 and the reciprocating movement of a lens 19 by a swaying shaft 13 allow the lower surface of the lens 19 to be polished. Since the clearance S is provided between the center part of the pressure-applying cap 3 and a holding pan 2, the load to be applied by a weight 20 to the center of the pressure-applying cap 3 through the swaying shaft 13 is transmitted to the periphery of a recessed part 4 of the holding pan 2, and distributed from the periphery to the whole upper surface of the lens 19. Thus, the load applying on the lens 19 forms the distribution of the shape of two triangles where the load becomes maximum at the position corresponding to the peripheral part of the recessed part 4 of the holding pan 2 and decreases toward the center part and the periphery of the lens 19, and an approximately uniform load distribution can be obtained over the whole surface of the lens 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing holder particularly suitable for a large-diameter lens of 60 mm or more.

[0002]

2. Description of the Related Art FIG. 4 shows a lens polishing machine, which comprises a polishing dish 11, a lens holder 12 and a swing shaft 13.
And a swing arm 14. The polishing dish 11 is provided on the upper end of a drive shaft 18 that is rotationally driven by a motor 15 via a belt 16 and a pulley 17. Holder 1
The reference numeral 2 holds the lens 19 placed on the polishing dish 11. The lower end of the swing shaft 13 is rotatably connected to the center of the upper surface of the holder 12, the upper end is appropriately supported, and a weight 20 is added. Swing arm 14
Is swingably provided on the fixed base 21 in the horizontal direction (perpendicular to the plane of the drawing), and its tip is connected to the swing shaft 13. The swing arm 14 has a drive shaft 24 that is rotationally driven by a motor 15 via a belt 22 and a pulley 23.
A crank arm 26 provided on the rotary plate 25 of FIG.

In this polishing machine, a lens 19 held by a holder 12 and given a constant load by a weight 23 shakes on a polishing dish 11 rotating in the direction of arrow R, as shown in FIG. Arrows P and P'by moving arm
As a result of reciprocating movement in the meridian direction indicated by, the lower surface of the lens 19 is polished. As shown in FIG. 6, this holder 12 is a holder 1 directly attached to the upper surface of the lens 19 with an adhesive.
2a or a cross 2 on the upper surface of the lens 19 as shown in FIG.
There is a holder 12b which is composed of a holding plate 28 placed via the holder 7 and a holder 29 which covers and holds the holding plate 28 and the lens 19.

[0004]

However, in the above-mentioned conventional holders 12a and 12b, the lens 19 is pressed against the entire surface and a load is applied to the center thereof, and therefore, as shown in FIG. At the additional point, the triangular distributed load that decreases at the maximum at the additional point acts on the lens 19. That is, the load is applied to the center of the lens 19, but the load is hardly applied to the periphery.
For this reason, the outer circumference of the lens 19 is not sufficiently polished, and the spherical curvature accuracy of the center of the polishing dish 11 is deteriorated, so that the polishing dish 11 must be replaced every time several lenses 19 are polished. This tendency becomes more remarkable as the lens 19 has a larger diameter, and the plastic lens having a large diameter which has been popular recently cannot be polished by the above method. The present invention has been made in view of the above problems, and an object of the present invention is to provide a polishing holder for a large-diameter lens that can hold the lens in a substantially uniform distribution load state.

[0005]

In order to achieve the above object, the present invention is for polishing a large-diameter lens that reciprocates by holding a lens placed on a polishing dish from above. The holder includes a holding plate installed on the upper surface of the lens and a pressure cap attached on the holding plate, and a gap is provided between the center portion of the holding plate and the pressure cap. It is a thing. Here, the term “lens” is a concept that includes not only an original lens but also a lens mold. That is, it also includes a mold holder of a polishing machine for polishing the surface of a mold for molding a lens.

[0006]

Since there is a gap between the pressure cap and the central portion of the holding tray, the load acting on the center of the pressure cap is transmitted to the peripheral portion excluding the central portion of the holding tray, and the peripheral portion of the holding tray. The particles are almost evenly dispersed on the lens surface.

[0007]

Embodiments of the present invention will now be described with reference to the accompanying drawings. FIG. 1 shows a lens holder 1 according to the present invention, and since the polishing machine to which the holder 1 is attached is the same as the conventional one described above (see FIG. 4), its explanation is omitted. The holder 1 includes a circular holding plate 2 and a pressure cap 3. The holding plate 2 is made of a casting having substantially the same diameter as the lens 19 to be polished, the lower surface thereof has the same curved surface as the upper surface of the lens 19, and the upper surface thereof is a flat surface. A circular recess 4 is formed in the center of the upper surface of the holding plate 2. The pressure cap 3 is made of a casting having the same diameter as the holding tray 2, a convex portion 5 that fits into the concave portion 4 of the holding tray 2 is formed on the lower surface, and the lower end of the swing shaft 13 of the polishing machine is formed on the upper surface. Is formed with a spherical recess 6 into which is freely rotatably fitted. When the convex portion 5 of the pressure cap 3 is fitted into the concave portion 4 of the holding tray 2, the convex portion 5 and the concave portion 4
A gap S is formed between them.

The holder 1 having the above structure is attached to the polishing machine as follows. First, the lower surface of the holding dish 2 is adhered to the upper surface (non-polished surface) of the lens 19 with an adhesive, and the lens 19 is placed on the polishing dish 11. Next, the pressure cap 3 is attached to the lower end of the rocking shaft 13 of the polishing machine, and the pressure cap 3 is placed on the holding plate 2 so that the convex portion 5 of the pressure cap 3 and the concave portion 4 of the holding plate 2 are formed. Mating.
Then, as shown in FIG. 4, a weight 20 is added to the swing shaft 13. Then, when the polishing machine is operated as described above, the lens 1 is rotated by the rotary motion of the polishing plate 11 and the swing shaft 13.
By the reciprocating movement of 9, the lower surface of the lens 19 is polished.

Since there is a gap S between the central portion of the pressure cap 3 and the holding plate 2, the load applied to the center of the pressure cap 3 by the weight 20 through the swing shaft 13 is the holding plate 2.
Is transmitted to the peripheral edge of the concave portion 4 and is dispersed from the peripheral edge to the entire upper surface of the lens 19. Therefore, as shown in FIG. 2, the load acting on the lens 19 has an apex at a position corresponding to the peripheral edge portion (shown by the diameter A) of the concave portion 4 of the holding dish 2, and from the apex to the central portion and the periphery of the lens 19. There are two triangular distributions that decrease toward the edges, and as is clear from comparison with the conventional load distribution shown in FIG. 8, there is a substantially uniform load distribution over the entire surface of the lens 19. Therefore, the lens 19
Since the load is distributed to the peripheral portion of the lens, even if it has a large diameter like a plastic lens, the lower surface of the lens 19 is uniformly polished over the entire surface. Further, the polishing plate 11 does not have uneven wear only in the center unlike the conventional case.

FIG. 3 shows a holder 1a according to another embodiment of the present invention. The holder 1a comprises a holding plate 2, a pressure cap 3a and a holder 7. The holding tray 2 and the pressure cap 3a are almost the same as those in the above-described embodiment, but the central portion of the upper surface of the pressure cap 3a projects upward for mounting the holder 7. The holder 7 is made of a synthetic resin such as Bakelite, and includes a flat portion 8 that covers the upper surface of the pressure cap 3a, and a cylindrical portion 9 that fits around the pressure cap 3a, the holding tray 2 and the lens 19. There is.

To attach the holder 1a to the polishing machine, first, the holding dish 2 is placed on the lens 19 placed on the polishing dish 11 via the cloth 10. Next, the pressure cap 3 a having the holder 7 mounted thereon is put on the holding tray 2, and the tubular portion 9 of the holder 7 is fitted around the holding tray 2 and the lens 19. As a result, the upper surface of the lens 19 is covered with the holding dish 2 and the side surface is held by the holder 7. The load acting on the center of the pressure cap 3a is almost evenly distributed over the entire surface of the lens 19 as in the holder 1 of the above-described embodiment.
In this embodiment as well, the lens 19 is uniformly polished to the periphery, and uneven wear of the polishing dish 11 is eliminated, which is the same effect as the above-described embodiment.

In the above embodiment, the holding plate 2 is provided with the concave portion 4 to form the gap S. However, the pressure caps 3 and 3a are provided.
A recess may be provided on the side to form a gap. Also, the recess 4
The diameter A should be determined by the size of the lens 19, but as a guide, it is preferably about 1/3 of the diameter of the lens 19. The lens holder according to the present invention can hold a round, square, or rectangular lens, and the polishing surface is not limited to a spherical surface, and a flat surface, an aspherical surface, or an astigmatic lens surface having different radii of curvature in two directions orthogonal to each other. It can be held even by a lens having It is also possible to replace the lens of the above embodiment with a mold, hold the mold with the holder of the present invention, and polish the surface of the mold with a polishing dish.

[0013]

As is apparent from the above description, according to the present invention, since the gap is provided between the central portion of the holding plate and the pressure cap, the load acting on the pressure cap is applied to the lens surface. The particles are evenly dispersed on the upper side, whereby the lens is uniformly polished to the peripheral portion, and even a plastic lens having a large diameter is highly accurately polished. Further, as a result of the load acting on the lens becoming substantially uniform as described above, the polishing dish also wears uniformly, so that as in the conventional case, only the central portion is unevenly worn and the polishing dish of the polishing dish is polished every time several lenses are polished. There is no need to replace the lens, and dozens of lenses can be polished by the same polishing dish, which is economical and improves productivity.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a holder according to the present invention.

FIG. 2 is a distribution diagram of a load acting on a lens when the holder according to the present invention is used.

FIG. 3 is a cross-sectional view showing another embodiment of the holder according to the present invention.

FIG. 4 is a schematic front view of a polishing machine.

5 is a plan view of the polishing machine of FIG.

FIG. 6 is a cross-sectional view showing an example of a conventional holder.

FIG. 7 is a cross-sectional view showing another example of a conventional holder.

FIG. 8 is a distribution diagram of a load acting on a lens when a conventional holder is used.

[Explanation of symbols]

1, 1a ... Holder, 2 ... Holding dish, 3, 3a ... Pressure cap, 11 ... Polishing dish, 19 ... Lens,
S ... gap.

Claims (1)

[Claims] 1. A holder for polishing a large-diameter lens that presses and holds a lens placed on a polishing dish from above to reciprocate the lens, and a holding dish installed on the upper surface of the lens. A holding tool for polishing a large-diameter lens, comprising: a holding cap attached on the holding plate, and a gap is provided between a central portion of the holding plate and the pressing cap.