JPH01147403A - Molded glass lens - Google Patents

Abstract

PURPOSE:To properly scatter incident rays on an optical function surface so that a soft focus image is obtd. with simple constitution by specifying the surface roughness of the optical function surface. CONSTITUTION:The surface roughness of the optical function surface 3a of a molded glass lens 3 is specified to 0.05-1.00mum Rmax. The respective rays 4a-4c are changed in direction by the positions where the rays pass the optical function surface 3a formed with ruggedness and are not condensed at one point. The resulted image is not sharp and is blurred. The soft focus image is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molded glass lens, and particularly to a molded glass lens for a rough 1 focus lens.

[Conventional technology]

-A molded glass with a desired optical function surface is formed by press-molding a heat-softened glass material into a flu with a pair of molds, without any post-processing such as polishing. Molded glass lenses are often used in optical devices such as cameras.

By the way, as a lens for a camera, a soft focus lens that can obtain a soft 1 meter photograph is known. Conventionally, soft focus lenses have been specially designed so that the lens itself has a soft focus from the beginning.
5! ■, only the y-plane aberration is intentionally made thicker (while leaving it, other aberrations are corrected as much as possible).
has been done.

[Problem that the invention seeks to solve]

However, with the above-mentioned conventional soft focus lenses, the design is extremely difficult, and it is complicated to design three lenses for each type of lens. It is known that a special butane (-) software or filter is installed as a means of illuminating the depiction, but in this case, the blurred image is
There were problems such as an odd shape and a decrease in the number of light meters, which resulted in moderate limitations in use.

The present invention has been made in view of such problems, and provides a molded glass lens that can produce a soft-focus image with a fold-over structure that does not require a new design of the lens optical system. 4 objectives.

547 Means for Resolving Problems] In order to solve the above-mentioned conventional problems, the present invention improves the surface roughness of the optical functional surface of a molded glass lens by R11ax0.0.
5 to 1.00 it m In the present invention, the surface 1'll of the optical performance surface is set to Rmax0.05.
The reason for setting it to ~1.00 μm is that, for example, when the surface roughness is about llv + x = o, ol // m like a normal Tokenai lens, and Rmax = less than 0.05 am, it is too smooth and exhibits a soft focus function. Also, if the surface t exceeds Riax = 1.00 μm, it will be too rough and unsuitable as an optical lens.6 Usually, foreign matter is embedded in the optically functional surface of a molded glass lens, or unevenness occurs. However, the present invention attempts to obtain a soft-focus image by taking advantage of the fact that foreign matter is embedded in the optical functional surface or that the surface is uneven. That is, in the present invention, foreign matter is embedded in the optically functional surface of the molded glass lens, or fine irregularities are provided to increase the surface roughness to Rmaxo, 05~
The objective is to construct a soft focus lens by incorporating this molded glass lens into an optical system.

[Effect]

In an optical system incorporating the molded glass lens of the present invention, the direction of the light ray changes slightly due to the irregularities provided on the optically functional surface of the molded glass lens, resulting in blurring at the focal point and soft focus. You can get a good image. Here, in the optical system, there is no need for a special design that increases spherical aberration, and one or more surfaces of the lenses in the normal optical system can be replaced with the molded glass lens of the present invention. Just that is enough.

[Example] (First example) SKI 1 was used as the glass material, outer diameter 25ml 1g
, with a thickness of 2.5++u and polished on both sides, is heated and softened in a nitrogen gas atmosphere to a temperature near the glass softening point (preferably 639°C ± 50°C in the case of SK11). A molded glass lens was obtained by press molding with a mold at a temperature lower than the glass transition point (if the glass transition point is 535°C, preferably 515 to 335°C). The optical functional surface of this molded glass lens is Rraa
x-0, 10 μm, and the uneven period was 3 to 15 μm.

The mold used in this example was aluminum nitride (80N
), which was produced by sintering 0.6 μm HEIN fine particles using a hot press method and then polishing, and the mold surface has fine irregularities caused by grain boundaries. The surface roughness of this mold is l1a as shown in 2nd L1.
ax=0.12 μm, and the uneven period was 3 to 15 μm. Here, the reason why the optically functional surface of the molded glass lens is smoother than the surface of the mold is that glass cannot flow into the minute recesses on the surface of the mold. Incidentally, the unevenness on the surface of the mold can be appropriately controlled by adjusting the /IN particle size, sintering conditions, polishing method, etc.

In this example, a 17-inch molded glass lens is used for light! 7. Figure 3 shows a lens configuration diagram of the soft focus lens when it is incorporated into a system. In Figure 3, l&! With mirror frame, mirror frame l
The lens 2 has four lenses 2 with smooth surfaces formed by ordinary grinding and polishing and one molded glass lens 3 obtained in this example, and has a R5 configuration of 4 m5 lenses. As described above, the optical functional surface 3a of the molded glass lens 3 is formed with fine irregularities, so the direction of the light ray changes slightly, causing blurring at the focal point, resulting in soft focus. Can be done.

On the other hand, all five lenses were ground by normal grinding and rIIF.
If you use a lens with a smooth surface given r=, you will not get a soft focus, but you will get a sharp image i'.

That is, it operates as shown in FIGS. 1a and 1b.

FIG. 1a shows a case where the molded glass lens 3 of this embodiment is used, and the direction of each light ray 4a, 4b', 4c changes depending on the position where it passes through the optical functional surface 3a on which the unevenness is formed, and one point Does not focus light on Therefore, f+1. In the 16th,
5. The image is not sharp but blurred. It is possible to create 17 soft focus images. The amount of blur can be controlled by the level difference and period of the unevenness of the optical functional surface 3a, and can be made into the optimal shape as appropriate.

On the other hand, with the lens 2 whose surface has been made smooth by ordinary grinding and polishing (U), each of the light rays 5a, 5b, and 5c are all focused at the focal point F, as shown in Figure 1a. , resulting in a sharp image.

(Second Example) SF as a glass material? (Glass softening point 592°C)
, @ used, the surface roughness of the optical functional surface is Rmaxo, 05 ~
1.00μm molded glass lens (also.

In particular, in this example, the melting point is sufficiently high (350
0'C) carbon powder is distributed almost uniformly on the lower part of the mold, and is compressed by this mold, thereby forming the optically functional surface of the molded glass lens made of carbon powder. The microparticles were pushed in and attached.

That is, as shown in FIG. 4, a concave portion 61 and a convex portion 62 are formed on the optically functional surface 6a of the molded glass lens 6 of this embodiment. Carbon powder 7 is attached to the recess 61.

In this molded glass lens 6, the convex portion 62 is a lens surface with a regular curvature that is not affected by the carbon powder, and the light ray passing through the convex portion 62 is focused as shown in FIG. focus on. On the other hand, the direction of the light rays passing through the four parts 61 formed by pushing the carbon powder 7 changes depending on the position, and the light rays are not focused on the focal point, but are blurred. Due to this blur, it is possible to obtain a soft-focus image with respect to °ζ in this embodiment. Furthermore, as in this example, by interposing fine particles between the glass material and the mold, mold release became easier than in normal molding.

In this example, ζ carbon powder was used as the fine particles, but the particles are not limited to this. For example, glass particles, carbon (Zuzu), (II'I!
It may be made of ceramic or the like, as long as it has a softening point higher than the softening point of the glass used for the lens.

Moreover, the fine particles may be shaped into a shape (J"6) by electric force, for example, by applying an electric field, regardless of the method of scattering the fine particles onto the lower mold.

(Third Example) 5FII was used as the glass material, which was finely ground with a grindstone in which diamond abrasive grains with a grain size of No. 1500 were embedded in resin. The shape of the material is finished to be close to the final lens shape, and while it is held between a pair of molds, it is heated to the glass yield point, and molded by applying a pressure of lOkgr/(・I. After slow cooling to a temperature below 100 mL, the molded glass lens was taken out from between the molds.

The surface size of the optically functional surface of this molded glass lens is R+n
IIx=0.2 μm, and when this lens was incorporated into an optical system, the light rays were appropriately disturbed by 11′i, and a soft focus image could be obtained.

As described above, by using each of the molded glass lenses of Examples 1 to 3, it is possible to easily construct a soft focus lens even if the optical system (lens configuration) is the same as the optical system that can obtain a sharp image. can.

Here, there is no limitation as to which lens in the optical system should be replaced with the molded glass lens of the present invention. Effective aspects and ineffective aspects differ depending on the lens type.

(Effects of the Invention) As described above, according to the molded glass lens of the present invention, the surface roughness of the optical functional surface can be reduced to R+aax0.05 to 1.00μ.
rn, the incident light ray is scattered appropriately on the optical functional surface, and a soft) focused image is created with a simple 171 composition in the extremely 'ζ section. ), and it can also be made into a soft focus lens without designing a new lens optical system.

[Brief explanation of the drawing]

Fig. 1a is a side view showing the direction of light rays passing through a molded glass lens according to the first embodiment of the present invention, and Fig. 1A shows light passing through a normal lens! , Figure 2 is a graph showing the surface roughness of the mold used in the first embodiment of the present invention, and Figure 3 is a diagram showing the molded glass lens of the first embodiment of the present invention. Vertical sectional view showing the state where SJI is included in the optical system, No. 4r
A is a vertical sectional view showing the main parts of a molded glass lens according to a second embodiment of the present invention. 3.6... Molded glass lens 3a, Ga... Optical '7 Functional surface 7... Carbon powder 61... Fourth part 62... Convex portion °17 Allowance 1 + Person A Olympus Optical Industry Co., Ltd. No. 3 Figure 4

Claims (1)

[Claims] (1) The surface roughness of the optical functional surface is Rmax0.05-1.
A molded glass lens characterized by having a diameter of 00 μm.