HK1160418B - Molding for optical purposes, particularly filter ring or lens holder - Google Patents

Description

Moulding component for optical applications, in particular filter ring or lens frame

Technical Field

The invention relates to a molding unit for optical applications, in particular a filter ring or filter frame, comprising a disk-shaped optical body made of glass, such as a lens, a filter or shutter, and a frame, in particular an additional filter or an additional filter, in particular a filter ring.

Background

In photographic practice it is often necessary to use additional color filters, filters and light shields that are temporarily attached to the frame of the camera lens.

Most typically, these additional filters, filters or shades have a metal circular frame, which is often internally or externally threaded. The frame can be screwed into the corresponding internal thread through the external thread on the outer side surface of the filter ring. Other filter frames of the same type can be fixed in the inner threads of the frame on the inner side surface of the frame. The threaded connection can mount various optical lenses on the lens according to the needs of the user.

The circular frame used today is made up of a plurality of individual parts, an outer ring and an inner ring mounted on the outer ring, and a kind of snap ring. The outer ring has a concentric ring of steps on its inner face, the steps being disposed at a position which is half the axial height of the ring. The disc-shaped filter (or other optical lens) is placed on the step, which is held in this position by a snap ring, so that the inner ring screwed into the outer ring supports the snap ring and has, on its front side, a ring of steps projecting in the direction of the axis of rotation of the rim, which steps are directed against the disc-shaped filter. So that the inner ring does not screw completely into the outer ring but projects beyond the axial direction. The outer frame of the extension of the inner ring supports the external thread of the rim that can be fixed to the lens. On the inner frame surface of the outer ring, the inner frame surface is adjacent to the side edge of the step, the side edge avoids the filter lens, the inner thread of the frame seat is formed, and other frames of the same type can be fixed.

The parts of the frame are made of metal, usually brass, and they almost all have a black coating.

The manufacture of such additional lenses or filters is labor intensive and requires numerous steps from the manufacture of the individual components to the assembly of the components and optical elements. In addition, the coatings of the additional lenses or filters tend to whiten after multiple uses, particularly in the region of the threads, and secondly in the region where the frame is exposed. Further, the optical component cannot be moved within the bezel.

Such additional lens, filter or lens-like rim is known from AT 140645 and is made of a resilient, elastic material. The frame body surface of the frame at the inner side is provided with a circle of concentric grooves, the lens can be embedded into the grooves, and the lens can be conveniently embedded due to the characteristics of elastic and flexible materials. Due to the elastic characteristic, the frame can be clamped on the lens clamping seat.

However, the frame made of elastic material needs to be screwed into the lens mount on one hand and needs to be matched with other frames of the same type on the other hand. Furthermore, the use of such a frame does not guarantee whether additional lenses, additional filters, etc. can be in the optical axis of the lens in practice, which may affect the quality of the photographic image.

DE 19615371C 2 discloses a glass plate, in particular for kitchen cooktops, which is injection-molded into a plastic frame. The frame is formed into a glass sheet by a closed hot pressing process, which functions to provide a shrinkage-absorbing member disposed between the frame and the injection-molded glass body. In addition, the shrinkage absorbing member should prevent the glass sheet from being broken because it can absorb various stresses generated in the case of normal use of the glass.

However, shrinking the absorbing member also causes a shifting of the lens or filter, since it is hardly guaranteed that the shrinking process is performed at a constant rate.

Disclosure of Invention

The object of the present invention is to overcome the drawbacks of the prior art and in particular to provide a molding assembly for optical applications having an optical component and a frame, which is inexpensive to manufacture, ensures an exact or even unchanged position of the optical component in the frame and can be fixed precisely on the lens.

The problems posed by the invention are solved in the statements of claims 1 and 10. Practical arrangements of the invention can be derived from the features of claims 2 to 9 and 10 to 12.

According to the manufacturing method of the present invention, there is provided a molded component for optical use, which includes a disk-shaped glass optical body, and an injection-molded frame in which the disk-shaped optical body is enclosed by a hard plastic material. The frame is used for embedding the disc-shaped optical body in the disc-shaped optical body according to the shape of the disc-shaped optical body. The preferred rim is annular.

The disk-shaped optical body is made of glass. Such optical bodies should have very high mechanical strength values in order to achieve the required optical properties and the required mechanical stability.

The disk-shaped optical body is, for example, a filter, in particular a polarizing filter or a UV filter, or a filter. The disk-shaped optical body is preferably a cylinder.

The preferred molding element for optical applications according to the invention is an additional filter, in particular a filter ring.

In contrast to the state of the art, the molding assembly of the present invention can be completed in one process step, since the frame of the molding assembly does not have to be formed from individual parts. Furthermore, it is avoided that the threads of the individual components have to be aligned with each other during the manufacture of the components. The injection molding process based on the disk-shaped optical body and the tight combination of the shape matching between the frame and the optical body can avoid the slippage phenomenon of the optical body under any condition, thereby leading the whole molding assembly to achieve high stability.

The plastic part may optionally be painted. But the frame or parts thereof need not be painted. Therefore, no paint layer will peel off.

In a preferred embodiment of the present invention, the outer body surface of the annular frame is provided with external threads, and the inner body surface of the annular frame is provided with internal threads.

In addition, a first step and a second step are arranged on the inner main body surface of the annular frame in a concentric whole circle mode according to the application. This allows the disk-shaped optical body to be embedded between the first step and the second step.

Preferably, the second step is adjacent to a first vertical surface of the annular frame, wherein the first step is spaced apart from both the first vertical surface and a second vertical surface of the annular frame. In addition, the inner main body surface range of the annular frame is provided with internal threads arranged between the first step and the second vertical surface of the annular frame. The main body surface on the outer side is mainly provided with a concentric circle of grooves or a cone, wherein the main body surface of the grooves or the cone is provided with external threads.

First, the plastic is a thermoplastic polymer, mainly polyamide or polyamide 6, especially glass-particle-cast polyamide 6, depending on the application. The plastic should have sufficient mechanical strength and elasticity and a small cross section so that large stresses can be counteracted and/or absorbed. The plastic has good elasticity at ambient temperatures of-25 to +85 ℃, so that different temperature coefficients between the glass and the plastic can be balanced. The stress difference is thus adjusted by the elastic force of the plastic.

The optical body and the frame of the disk are mutually connected in a shape matching elastic deformation mode.

Further, according to an embodiment of the present invention, there is provided a method of manufacturing a novel molding assembly for optical use, the method comprising the steps of:

(a) inputting the disc-shaped optical body into an injection mold of an injection molding machine;

(b) the disc-shaped optical body is shaped in the injection mold through a mold insert, the mold insert is contacted with the surface side of the disc-shaped optical body, and the optical body is exposed out of the main body surface of the optical body;

(c) injecting plastic into a mold cavity, the mold cavity defining the dimensions of the disc-shaped optical body; and is

(d) During the process of forming the one-piece injection molded rim, the plastic begins to harden.

Finally, the finished molded assembly can be removed from the injection molding machine. The surface unevenness of the disc-shaped optical body is flattened by a mold insert. This has the advantage that the injection mould is closed by the closing pressure after injection of the disc-shaped optical body and determines the position of the mould insert which is reached when it comes into contact with the disc-shaped optical body, wherein the mould insert is arranged such that irregularities on the surface side of the optical body are leveled.

In the embodiment of the invention for manufacturing optical filters, the filter glass is treated (also referred to as machined) in the mold cavity, for which purpose the position of the filter glass is fixed precisely. The correctly positioned and pre-fixed filter glass plate, called insert, is then processed in the cavity of the opened injection mold. The injection mold holds the insert by means of a vacuum pump and is then removed from the opened injection mold. The injection mould is then passed through the closing pressure and the mould insert corrects the thickness tolerance of the filter glass plate by about +/-0.2 mm. In this case, the filter glass plate remains fixed in its position without radial contact with the inner wall of the injection mold. The mold members, in particular the mold inserts, the slide blocks and the adjusting screws, shape the contour of the plastic frame on the filter glass. The pellets are injected through a gate system of an injection molding machine through a mold cavity formed by the mold insert and the filter glass sheet. And after the material particle melt is cooled, opening the injection mold to expose the molding assembly. When the mold is opened, the sprue will fall off from the molding assembly automatically after the filter ring is taken down. After the treatment of the injection mould, the cast glass filter can be taken out.

Drawings

The invention is not limited to the embodiments described above, but is further illustrated below with reference to the following figures and examples:

FIG. 1 is a perspective view of a filter ring according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of the filter ring shown in FIG. 1;

FIG. 3a is a front view of the filter ring shown in FIG. 1;

FIG. 3b is a side view of the filter ring shown in FIG. 3;

FIG. 3c is a cross-sectional view of the filter ring shown in FIG. 3 taken along line A-A;

FIG. 3d is a cross-sectional view of the filter ring shown in FIG. 3 taken along line B-B;

FIG. 4 is an enlarged cross-sectional view of section Y of FIG. 3 c;

FIG. 5 is an enlarged cross-sectional view of section X of FIG. 3 d;

FIG. 6 is an enlarged cross-sectional view of section Z of FIG. 3 b;

fig. 7 is an enlarged cross-sectional view of section W of fig. 3 a.

Detailed Description

As can be seen from the figure, the filter ring 1 according to the invention is composed of a cylindrical filter glass plate 2 and an injection-molded frame 3 which encases the filter glass plate 2. The frame is made of polyamide 6 containing 30% by weight of glass frit (product name: Akromid B3 GK 30, available from Akro-Plastic responsibility Co., Ltd., Niederzissen, DE).

The frame 3 is circular. The inner main body surface of the circular frame is provided with a first step 4 which concentrically surrounds the whole circle and a second step 5 which concentrically surrounds the whole circle, and the second step 5 and the first step 4 are mutually separated. The second step 5 is adjacent to the first end face 6 of the annular frame, while the first step 4 is spaced from both the end face 6 and the second end face 7 of the annular frame 3, at a height approximately half the axial extent of the frame 3. The filter glass sheet 2 is fitted between the first step 4 and the second step 5.

In the region 8a of the inner main body surface 8 of the annular frame 3, which is arranged between the first step 4 and the second end surface 7 of the annular frame 3, the internal thread of the frame 3, to which a further additional lens or a further additional filter, for example a filter ring, is connected, is injection-molded. Preferably, a concentric, full-circle cone structure 10 is provided on the outer body surface 9, which concentric, full-circle cone structure has external threads, by means of which the molded component can be screwed into the lens frame.

The outer body surface 9 may also be provided with a complete circumferential groove 11 to facilitate screwing the molding assembly 1 into and out of the lens frame.

Description of the reference numerals of the main components

1 Filter ring

2 Filter glass

3 rims

4 first step

5 second step

6 first end face

7 second end face

8 inner main body surface

8a inner body surface area

9 outer main body surface

10 vertebral body

11 groove line

Claims (9)

1. A filter ring for optical use, comprising a sheet-like optical body (2) made of a glass, and an annular single injection-molded rim (3) in which the sheet-like optical body (2) is fitted with a hard plastic material, wherein the sheet-like optical body (2) is a cylindrical body or a lens body having unevenness on the surface side thereof; and wherein the step of (a) is,

the frame (3) embeds the sheet optical body (2) with tolerance according to the shape thereof;

the outer side main body surface (9) of the annular frame (3) is provided with external threads, and the inner side main body surface (8) of the annular frame (3) is provided with internal threads;

the inner main body surface (8) of the annular frame (3) is provided with a 1 st-level concentric one-circle surrounding step (4) and a 2 nd-level concentric one-circle surrounding step (5) which keeps an interval with the 1 st-level concentric one-circle surrounding step (4), wherein the sheet-shaped optical body (2) is embedded between the 1 st-level concentric one-circle surrounding step (4) and the 2 nd-level concentric one-circle surrounding step (5); and

the optical use filter ring is obtained by the following steps:

-inserting the sheet-like optical body (2) into an injection mould of an injection moulding machine;

-fixing the sheet-like optical body (2) in the injection mold with a mold insert, the mold insert being in contact with both surface sides of the sheet-like optical body, wherein the sheet-like optical body (2) is exposed at its main body surface;

-injecting pellets into the mould cavity, which are defined in position by the mould insert and the sheet-like optical body (2); and

-during the formation of the individual injection-moulded rim (3), the plastic begins to solidify;

wherein the uneven portion on the surface side of the sheet-like optical body (2) is leveled by means of the mold insert.

2. A filter ring according to claim 1, wherein: the 2 nd-level concentric surrounding ring step (5) is adjacent to the 1 st end side (6) of the annular frame (3), the 1 st-level concentric surrounding ring step (4) is separated from the 1 st end side (6) and the 2 nd end side (7) of the annular frame (3), wherein the range (8a) of the inner main body surface (8) of the annular frame (3) is provided with internal threads, and the internal threads are arranged between the 1 st-level concentric surrounding ring step (4) and the 2 nd end side (7) of the annular frame (3).

3. A filter ring according to claim 1, wherein: the outer main body surface (9) of the annular frame (3) forms a concentric circular cone structure (10), wherein the main body surface of the cone structure (10) is provided with external threads.

4. A filter ring according to claim 1, wherein: the sheet-like optical body (2) is a filter.

5. The filter ring of claim 4, wherein: the sheet-like optical body (2) is a polarizer or a UV filter.

6. A filter ring according to claim 1, wherein: the plastic material is a thermoplastic polymer.

7. The filter ring of claim 6, wherein: the plastic material is polyamide.

8. A method of manufacturing a filter ring according to any of claims 1 to 7, comprising the steps of:

-injecting the sheet-like optical body (2) into an injection mould of an injection moulding machine;

-fixing the sheet-like optical body (2) in the injection mold with a mold insert, the mold insert being in contact with both surface sides of the sheet-like optical body, wherein the sheet-like optical body (2) is exposed at its main body surface;

-injecting pellets into the mould cavity, which are defined in position by the mould insert and the sheet-like optical body (2); and

-during the formation of the individual injection-moulded rim (3), the plastic begins to solidify;

-the uneven part of the surface side of the sheet-like optical body (2) is leveled by means of a mold insert.

9. The manufacturing method according to claim 8, characterized in that: after the sheet-shaped optical body (2) is placed, the injection mold is closed by a closing pressure, the position of the mold insert is fixed, and the mold insert is in contact with the sheet-shaped optical body (2), wherein the mold insert is arranged so that uneven portions on the surface side of the sheet-shaped optical body (2) are leveled.