JPH0949908A - Mirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mirror excellent in environmental resistance and usable in a photographing system and a polarization scanning system at a low production cost without requiring a skillful technique such as polishing by forming a mirror body having a required reflection surface by die-casting a low m.p. metal or alloy. SOLUTION: A roof mirror as an example of the mirror of a finder is composed of a sprue 1, a runner 2, a mirror body 3 as a cast article and mirror faces 4, 4' of the roof mirror. The mirror body 3 is formed by injection-casting a low m.p. metal or alloy with a prescribed injection casting machine. The m.p. of the metal or alloy is <=500 deg.C. The low m.p. metal is selected from among Sn, Bi, Pb, Cd and In. The low m.p. alloy is preferably an alloy of two or more kinds of low m.p. metals such as Si, Bi, Pb, Cd and In.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a mirror provided as a finder system mirror or a deflection scanning system mirror.

[0002]

2. Description of the Related Art Conventionally, a finder system mirror or a deflection scanning system mirror is used to form a reflection surface of an optical glass blank or a metal blank such as an aluminum alloy after mirror-polishing it. In general, a metal thin film is formed by vapor deposition means.

In recent years, in order to cope with the complicated shape of the reflecting surface and to reduce the manufacturing cost of the mirror body, a blank is molded with synthetic resin, and a metal thin film is vapor-deposited on the portion corresponding to the reflecting surface. Then, the mirror is completed.

[0004]

However, according to the above-mentioned conventional technique, the process of mirror-polishing a blank made of optical glass or metal requires a lot of labor and time, and requires a skilled technique. Also, when the blank is molded with synthetic resin, the intention of complicating the shape and reducing the cost is satisfied when the mirror body is formed, but unlike the case of optical glass or metal, the coefficient of thermal expansion is large. thing,
Due to the small heat transfer coefficient and physical weaknesses such as hygroscopicity, even if a highly accurate reflective surface is formed, the accuracy may change due to changes in the ambient temperature and humidity of the environment in which the mirror is used. is there.

The present invention has been made in view of the above circumstances, has a low manufacturing cost, does not require a skilled technique such as polishing, and has excellent environmental resistance, and can be used in a mirror or a scanning system. Is intended to provide.

[0006]

Therefore, in the present invention,
Molding low melting point metal material or low melting point alloy material,
It is characterized in that a mirror body having a required reflection surface is constructed.

As a result, since the material has a low melting point, the mirror body can be molded by using a molding die, a device, and a method for synthetic resin. Therefore, it is possible to cope with the complicated shape and reduce the manufacturing cost. Further, since the material is a metal or an alloy, the thermal expansion coefficient, which is a problem with synthetic resin, is large, the heat transfer coefficient is large, and there is no physical weakness such as hygroscopicity. Therefore, there is an advantage in that the accuracy of the reflecting surface does not change during the use process.

In this case, the low melting point alloy material is Sn, B.
Binary low melting point metals such as i, Pb, Cd and In,
It is preferably a ternary or multi-component alloy. Also,
The mirror body may be a hollow body.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 shows an example of a roof mirror, which is a viewfinder mirror, as an embodiment of the present invention, in which reference numeral 1 is a sprue, 2 is a runner,
3 is a mirror body (blank) as a molded product, 4, 4 '
Is the mirror surface of the Dach mirror.

The mirror body is injection-molded by using a low-melting metal material or a low-melting alloy material by means of an injection molding machine as shown in FIG. The material used here is a metal or alloy having a melting point of 500 ° C. or lower, and as the low melting point metal, Sn, Bi, P
b, Cd and In can be selected, and the low melting point alloy is preferably a binary, ternary or multi-component alloy of a low melting point metal such as Sn, Bi, Pb, Cd and In. The alloys used in this embodiment include those shown in Table 1.

[0011]

[Table 1] At the time of molding the mirror body, the ingot of the above-mentioned low melting point metal or low melting point alloy is crushed into pellets (indicated by reference numeral 10), which are supplied from the hopper 11 to the heating cylinder 13 via the feeder 12. , In a semi-molten state (state below the melting point of the metal material and above the freezing point), through the nozzle 14, the movable mold 1
It is injected into the cavity 19 formed by 7 and the fixed mold 18. In the figure, reference numeral 15 is a fixed platen, and 16 is a movable platen.

[0012] The mold temperature is set below the freezing point of the metal material and above the transition temperature, and after solidification, the metal material is gradually cooled near the transition temperature of the metal material.
After quenching to a temperature that does not deform, open the mold,
Take out the molded product. The sprue 1 left after molding
The or runner 2 can be crushed again and reused as pellets.

As an example of molding conditions, Bi
In the case of —Sn (melting point 170 ° C.), the temperature of the heating cylinder is 160 ° C., the injection speed is 1000 mm / sec, the temperature of the mold is raised to 90 ° C., and then slowly cooled to 70 ° C. at 1 ° C./min. It is controlled by a temperature cycle in which it is rapidly cooled to 50 ° C at 5 ° C / min.

The reflecting surface of the molded mirror body is 80%
When the above reflectance is required, a metal film is laminated on the surface by a known film forming method, and this is used as a reflection enhancing film or a protective film.

As described above, by using the low melting point metal and the low melting point alloy, particularly by using the low melting point multi-component alloy, it is possible to use the molding machine, the mold, the mold temperature adjusting device and the like in the equipment used. , No special high temperature measures are required, and equipment cost can be reduced. Further, the molding method is not limited to the above-mentioned injection molding,
Most molding methods used in synthetic resin molding such as compression molding, vacuum molding and blow molding can be applied.

(Embodiment 2) FIG. 2 shows a rotary polygon mirror as a deflection scanning system mirror, which is formed by injection molding the above-mentioned low melting point metal or low melting point alloy. In the figure, reference numeral 5 is a sprue, 6 is a molded product,
Reference numerals 7 and 7 ′ are reflective surfaces. Further, FIG. 2B shows a state after the gate is cut.

(Embodiment 3) FIG. 3 is a cross-sectional view of a hollow-molded product obtained by injecting air or a gas such as nitrogen or argon into a molding die during injection molding. In this way, the weight and thickness of the product can be reduced, the cooling time can be shortened, and the molding cycle can be shortened. In particular, since the rotary polygon mirror has a problem of inertia during rotation, unlike the optical element made of aluminum or synthetic resin, Bi or B having a large specific gravity is used.
In the case of the i-based alloy, the use of the i-type alloy is of great significance in order to reduce the motor load and reduce the power consumption. This not only reduces the weight of the optical element, but also contributes to the reduction of the weight of parts of the scanner unit and the cost reduction by reducing the weight of the motor and the like.

In the figure, reference numeral 8 is a hollow portion, and 9 is a trace of an air or gas injection port. Of course, the sprue 5 may be provided with a gas charging port.

[0019]

As described above, according to the present invention, a low melting point metal material or a low melting point alloy material is molded to form a mirror main body having a required reflection surface. The mirror body can be molded by using a mold, an apparatus, and a method. Therefore, it is possible to cope with the complicated shape and reduce the manufacturing cost. Further, since the material is a metal or an alloy, the thermal expansion coefficient, which is a problem with synthetic resin, is large, the heat transfer coefficient is large, and there is no physical weakness such as hygroscopicity. Therefore, there is an advantage in that the accuracy of the reflecting surface does not change during the use process.

[Brief description of drawings]

FIG. 1 is a side view of a molded product showing an example of an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional side view of a molded product showing another embodiment of the present invention.

FIG. 3 is a vertical sectional side view showing still another embodiment of the present invention.

FIG. 4 is a side view in which a part of the molding apparatus used in the embodiment of the present invention is vertically cut.

[Explanation of symbols]

 1,5 Sprue 2 Runner 3 Dach mirror 4, 4 ', 7, 7'Reflecting surface 6 Rotating polygon mirror 8 Cavity 9 Trace of gas inlet 10 Pellet 11 Hopper 12 Material supply device 13 Heating cylinder 14 Nozzle 15 Fixed platen 16 Movable Platen 17 Movable mold 18 Fixed mold 19 Cavity 20 Heater

Claims (3)

[Claims] 1. A mirror, characterized in that a low melting point metal material or a low melting point alloy material is molded to form a mirror body having a required reflecting surface. 2. The low melting point alloy material is Sn, Bi, P
The mirror according to claim 1, which is a binary, ternary or multi-component alloy of a low melting point metal such as b, Cd and In. 3. The mirror according to claim 1, wherein the mirror body is a hollow body.