JPH01167804A - Optical parts mold - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is designed to prevent the need for blocking unnecessary light beams other than the effective diameter with mounts or coatings when using optical components such as lenses, mirrors, and prisms. This invention relates to an optical component mold that can transfer a rough surface on which light rays are scattered.

Conventional technology Optical instruments such as cameras, microscopes, binoculars, and telescopes include
Optical components such as lenses, mirrors, and prisms are often used. These optical instruments are mainly intended to form two-dimensional or three-dimensional images. Therefore, if a portion of the surface of each optical component is not mirror-finished, light rays will be scattered there and the image will appear to have flare, resulting in an image with poor contrast. To block unnecessary light, we cover that area with a mount or paint it with black paint. On the other hand, recently, devices such as optical disk devices and laser beam printers that use a laser as a light source and whose purpose is not to form an image but rather to concentrate energy have been developed. Since these optical systems image a point light source emitted from a laser onto a negative point, scattering in the optical system, for example in the case of a laser beam printer, does not pose a problem as long as it is below the sensitivity of the photosensitive material.

Furthermore, in recent years, many molded products of glass and plastic have been used in these laser optical systems, and since they are laser optical systems, there is no need to correct chromatic aberration, which has led to a significant reduction in the number of optical parts. ing. (For example, Yoshitomi Nagaoka et al., “Industrial Materials J (April 1987 issue) P42~).

Problems to be Solved by the Invention However, even in the above-mentioned laser optical system, each optical component has a problem in that it blocks unnecessary light rays outside the effective diameter.
Since it requires means such as attaching a mount or applying black paint, it has problems such as complicated assembly and adjustment and high cost.

In view of the above problems, the present invention provides an optical component mold for molding an optical component that does not require a mount or painting to block unnecessary light rays.

Means for Solving the Problems In order to solve the above problems, the optical component mold of the present invention roughens all or part of the surface of the mold that forms the portion of the surface of the optical component that needs to block light rays. It is constructed so that it is a surface.

Effect of the Invention With the above-described configuration, the present invention can transfer the rough surface to the optical component by pressing the portion of the optical component that needs to block light with a mold that originally has a rough surface. When a light ray enters this portion, the light ray is scattered there, and as a result, the influence of unnecessary light rays on the image point can be significantly reduced.

EXAMPLE Hereinafter, an optical component mold according to an example of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of an optical component mold according to a first embodiment of the present invention. The lens mold 1 is for molding a convex surface. When actually molding the lens, prepare another mold similar to this one,
A desired lens shape is obtained by filling the space between two molds with a lens medium such as plastic or glass and pressing while keeping the mold at high temperature. A flat part 2 is provided at the upper part of the lens mold 1. This is because when the lens is molded, a flat portion is also formed on the lens side, making it easier to hold the lens. The lens effective surface forming portion 3 is a portion processed to form a designed lens surface. The lens effective surface forming portion 3 is processed to have a mirror surface, and the molded lens surface also has a mirror surface. On the other hand, an effective diameter outside lens surface forming section 4 exists between the lens effective surface forming section 3 and the flat section 2 . If there were no lens surface forming part 4 outside the effective diameter, the lens molded by the lens mold 1 would have a flat part from just outside the effective diameter. In this case, the direction of the light rays incident on the effective diameter and the light rays incident on the flat portion are different after refraction, which has the effect of blocking unnecessary light rays. However, when lens molding is performed, the mold shape is not sufficiently transferred to the lens at the edge portion between the flat portion 2 and the lens surface forming portion 3. This is because the surface shape changes rapidly. Therefore, in a general optical component mold, a lens surface forming part 4 outside the effective diameter is provided between the lens effective surface forming part 3 and the flat part 2, which is an extension of the shape of the effective diameter of the lens. In a lens molded with this type of mold, the lens surface outside the effective diameter and the lens surface inside the effective diameter are smoothly and continuously connected, so that the light rays incident on the lens surface outside the effective diameter are focused on the imaging point. have a large impact on Therefore, by making the lens surface forming part 4 outside the effective diameter and the flat part 2 a rough surface instead of a mirror surface, the outside of the effective diameter of the molded lens also becomes a rough surface, and light rays can be scattered. FIG. 2 is a side view of a lens molded with the lens mold 1. FIG. The effective diameter outer surface 5 of the lens is formed into a rough surface, and the effective diameter inner surface 6 of the lens is formed into a mirror surface. The flat part 7 of the lens can be used as a part to hold the lens.

FIG. 3 shows a sectional view of an optical system using a combination of three lenses molded by the optical component mold of the present invention. Each lens 8 and spacer 10 are sequentially dropped into the lens barrel 9 and assembled. Conventionally, when assembling such lenses, spacers have had the role of maintaining the distance between the lenses and at the same time setting the effective diameter of each lens. Therefore, the spacer and the lens were in contact with each other at the curved surface of the lens, that is, in the case of a spherical lens, at the spherical surface. Therefore, it has been difficult to assemble the lenses so that the optical axes of each lens are not tilted. However, when combining lenses molded using the optical component mold of the present invention, as shown in FIG. It is easy to keep them parallel.

On the other hand, light rays incident outside the effective diameter are scattered because the lens surface is rough. Generally, when a two-dimensional image is formed using a camera or a microscope, such scattered light becomes flare and deteriorates the image quality. However, in collimating lenses and fθ lenses for laser beam printers, and collimating lenses and objective lenses used in optical disc pickups,
The purpose is to concentrate the laser beam on one point, and unnecessary scattered light has almost no effect.

FIG. 4 is a perspective view of an optical component mold showing a second embodiment of the present invention. The molding surface of the mold 11 for molding the prism surface is divided into a mirror surface portion 12 and a rough surface portion 13. Mirror surface part 12
The prism surface transferred with the rough surface part 13 becomes a mirror surface and transmits or reflects the light beam, but the prism surface transferred with the rough surface part 13 becomes a rough surface and scatters the light beam. Therefore, the prism surface formed by the mold 11 can have a circular opening while having a square shape.

In the first embodiment shown in FIG. 1, the flat portion 2 is also made of a rough surface, but when the flat portion is covered with a spacer 10 as shown in FIG. Good too.

Further, in FIG. 2, both surfaces of the lens are provided with rough surfaces, but if it is sufficient to scatter light rays on only one surface, it is not necessary to provide rough surfaces on both surfaces of each lens.

Furthermore, we will discuss the surface roughness required for rough surfaces.

For example, in the case of precision molding of glass, sufficient transfer can be achieved even with a surface roughness of about 100 angstroms.

However, this surface roughness is insufficient for scattering light rays, so it is desirable for the optical component mold of the present invention to have a surface roughness of 0.1 micron or more.

Effects of the Invention As described above, the present invention provides a method for scattering light rays incident outside the effective diameter by roughening the surface of the mold that forms the portion of the surface of the optical component that needs to block the light rays. This eliminates the need for mounts and painting, which were conventionally required, and enables the molding of optical components that are easy to assemble.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an optical component mold according to the first embodiment of the present invention, Fig. 2 is a side view of a lens molded by the mold, and Fig. 3 is an optical system when three lenses are combined. The sectional view and FIG. 4 are perspective views of an optical component mold according to a second embodiment of the present invention. 1... Lens mold, 2... Flat part, 3... Lens effective surface forming part, 4...
- Effective diameter outer lens surface forming part. Name of agent: Patent attorney Toshio Nakao (1 person)

Claims (1)

[Claims] A mold for forming the surface shape of an optical component, characterized in that all or part of the surface of the mold that forms a portion of the surface of the optical component that needs to block light rays is roughened. Optical parts mold.