JPH03189603A - Optical reflecting mirror - Google Patents

Abstract

PURPOSE:To form the reflecting mirror to the high plane accuracy thereof and to contrive the improvement in efficiency and the reduction in cost by providing grooves for strain absorption on the rear surface of the mirror corresponding to the specular surface of the optical reflecting mirror and molding the mirror without exerting a holding pressure on the mirror. CONSTITUTION:A plastic material flows in a gate 11 through a sprue 14 and a runner 12 and is packed into a cavity 9 when the material is injected from a sprue bushing 13 mounted in the side wall surface of a stationary side mounting plate 1 and a stationary side mold plate 2. The plastic is packed into the cavity without applying the holding pressure thereon. The material packed into the cavity 8 begins to shrink on cooling and the plastic material in contact with the molding surface 28 of a stationary side piece 4 begins to peel. Linear projecting parts are provided on the molding surface 18 of the stationary piece 4 and, therefore, the rear surface of the molded mirror is eventually provided with the grooves for strain absorption and the mirror molding surface 10 of a movable side piece 8 is molded to the plane of the high accuracy and is transferred in this state to the molding member.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical reflective mirror molded from plastic.

[Conventional technology]

The conventional method for molding optical reflective mirrors was to fill an injection mold with plastic material under high pressure and use the pressure to invert the shape of the mold to obtain a highly accurate flat surface. Another method has been considered in which the temperature of the injection mold is controlled to prevent the molded reflective mirror from being deformed due to distortion.

Furthermore, some injection molded products had a hairline-like uneven pattern extending in the circumferential direction and perpendicular to the mold release direction on the circumferential surface.

[Problem to be solved by the invention]

A method of filling a plastic material into an injection molding mold under high pressure and using this pressure to invert the shape of the mold to obtain a highly accurate flat surface is already commonly used. However, with the method of injection molding under high pressure, it is possible to obtain good surface accuracy in the mold, but when the molded product is released from the mold, it is deformed (distorted) due to internal stress generated during molding.
occurs, and the plane accuracy is often distorted to such an extent that it cannot be used as an optical reflecting mirror.

Furthermore, regarding the above-mentioned method of controlling the mold temperature of the injection mold to prevent plane deformation, it is difficult to accurately and stably control the temperature difference between the stationary mold and the movable mold. Therefore, the molded product is warped and the surface accuracy is significantly deteriorated.

Furthermore, the above-mentioned method of forming a hairline-like uneven pattern extending in the circumferential direction and perpendicular to the mold release direction on the circumferential surface of the molded product cannot be applied because its purpose is different from that of molding an optical reflective mirror. Even if it were applied to an optical reflective mirror, it would be impossible to improve the flatness accuracy of the molded product.

The present invention was created in view of the above-mentioned problems.
The purpose of this invention is to efficiently and inexpensively provide an optical reflecting mirror that is molded without applying molding pressure, which is the main cause of deformation, and has the desired flatness accuracy.

[Means and effects for solving the problems] The present invention provides an optical reflecting mirror made of plastic, in which a plurality of straight, edged, or endless annular grooves for strain absorption are formed on the back surface of the mirror. It is a reflective mirror.

By forming the grooves as described above, the structure of the optical reflection mirror can be formed with high plane accuracy and angular accuracy, and can be provided efficiently and at a low cost.

〔Example〕

The configuration of the present invention will be explained based on the drawings.

In the drawings, members having the same shapes and configurations as in each of the embodiments are designated by the same reference numerals, and the description thereof will only be given to the first embodiment and subsequent embodiments will be omitted.

(First Embodiment) FIG. 1 is a plan view showing a cross section from the side of a molding die for molding an optical reflection mirror of the present invention.

FIG. 2 is an enlarged plan view showing the configuration of the cavity section shown in FIG. 1.

FIG. 3(a) is a perspective view showing the back side of the optical reflecting mirror according to the present invention molded by the mold shown in FIGS. 1 and 2. FIG.

FIG. 3(b) is a plan view showing a cross section taken along line AA shown in FIG. 3(a).

As shown in Figure 1, the fixed side mounting plate 1 has a flat plate shape at the top.
A cylindrical fixed side mold plate 2 is integrally attached to the outer peripheral edge of the lower end surface of the fixed side mounting plate 1. The fixed side template 2 has a cylindrical shape with a flange-shaped flange formed on the outer periphery of the upper end so as to protrude to match the step formed on the inner periphery of the upper end of the fixed side template 2. Fixed side sleeve 3
are integrally constructed. Furthermore, a cylindrical fixed piece 4 is integrally inserted into the inner periphery of the fixed sleeve 3. That is, the upper end faces of each of them are attached to the fixed side mounting plate 1, and the inner peripheral surfaces of each of them are tightly attached.

In addition, the lower end surface (molding surface) 18 of the fixed side piece 4 is made of a plastic material that has poor wettability, such as a molded plastic material, in order to improve the peelability between the molded member and the lower end surface 18 of the fixed side piece 4 after molding. A Teflon coat is formed. Further, although not shown, a long convex portion (protrusion) is formed on the lower end surface 18 of the fixed side piece 4 in order to form a groove for preventing deformation of the molded member near both side edges during molding of the molded member. There is.

A cylindrical movable mold plate 5 having the same dimensions as the outer and inner diameters of the fixed mold plate 2 of the fixed upper mold having the above structure is integrally mounted on the receiving plate 6. Furthermore, a cylindrical movable sleeve 7 is integrally formed on the inner periphery of the movable template 5 and has a flange-shaped flange that protrudes to match the step formed on the outer periphery of the upper end of the movable template 5. It is worn properly.

A cylindrical movable piece 8 is fitted onto the inner periphery of the movable sleeve 7 so as to be slidable in the vertical direction (axial direction).

The movable piece 8 has an upper end surface attached to the movable sleeve 7.
and the movable side mold plate 5, each of which has a lengthwise dimension shorter than the upper end surface thereof by a predetermined dimension to form a space. That is, a cavity 9 configured in a predetermined shape is provided between the upper fixed mold and the lower end surface of the fixed piece 4 to form a space (cavity) 9 in which a molded member is to be molded.

The upper end surface (molding surface) of the movable piece 8 of this cavity 9
Reference numeral 10 is formed to have a mirror finish with extremely high flatness in order to transfer and mold an optical reflective surface onto the molded member.

The respective boundary ends of the movable template 5 and the fixed template 2 on the lateral position of the receiving plate 6, that is, the lower end surfaces of the fixed sleeve 3 and the fixed template 2, and the movable sleeve As shown in the figure, a gate 11 and a runner 1 are provided on a part of the upper end surface of each of the mold plate 7 and the movable mold plate 5 to supply the plastic material into the cavity 9, which communicates with the cavity 9.
2 are connected in series.

Further, a funnel-shaped spool bush 13 is attached to the side wall surface of the fixed side mounting plate 1 and the fixed side mold plate 2 in one direction (right side), and a through hole, that is, a spool bush 13, is attached to the side wall surface of the fixed side mounting plate 1 and the fixed side mold plate 2 in one direction (right side). The tip opening of 14 is configured to communicate with one end of the runner 12, and when the plastic material is introduced into the spool bush 13, it is injected into the runner 12 through the spool 14, and further through the gate 11. It is configured to flow into the cavity 9 and fill it.

At the center position of the lower end surface of the movable piece 10 of the movable mold, at the lower end surface position on the tip side (gate 11 side) of the runner 12, and at the tip of the spool 14, that is, at the tip of the spool 14 in the axial direction. The core pin 15 and the runner protruding pin 16 are fitted into holes drilled in the receiving plate 6, the movable template 5, and the movable sleeve 7, which are disposed at the lower positions, respectively. and a spool ejecting pin 17 respectively, and the molded member after being molded in the cavity 9 is placed in the lower mold (movable mold).
They are configured to operate synchronously to improve mold release.

Further, the reference numeral 19 shown between the stationary mold and the movable mold is a parting line.

Next, a molding method using the molding die configured as described above will be explained.

First, as shown in the figure, when plastic material is injected from the spool bushing 13 attached to the side wall surfaces of the fixed side mounting plate 1 and the fixed side mold plate 2, the material flows through the spool 14 which is in communication with the spool bushing 13. It passes downward and flows into and passes through the runner 12 which is in communication with the spool 14. Further, from the tip of the runner 12, it passes through the gate 11, flows into the cavity 9, and is filled.

In the above case, the plastic material is filled without applying a holding pressure.

The plastic material filled in the cavity 9 is heated and begins to shrink as it cools. Along with this shrinkage, the plastic material in contact with the molding surface 18 of the stationary piece 4
Start peeling.

In this case, the above-mentioned shrinkage occurs with the upper end surface (molding surface) 10 of the movable piece 8 as a reference, and as a result, the mirror-finish molding surface lO1 of the movable piece 8 is molded while being molded to a high precision plane. It will be transferred to the member 20.

Furthermore, due to the linear protrusions formed on the molded surface of the fixed piece 4, the molded member (optical reflective mirror) 20 is molded near both side edges as shown in FIGS. 3(a) and 3(b)). Since the deformation absorbing grooves 21 and 22 are formed to have the thinnest thickness, they are cooled and hardened most quickly. Therefore, for the inside of the molded member 20, it serves as a kind of octagonal shield, and prevents deterioration of the plane precision of the mirror due to occurrence of warpage.

After waiting for the inside of the cavity 9 in which the molded part 20 has been molded to cool down, the lower mold is separated from the upper mold from the parting line 19.

In this case, the plastic material is in close contact with the movable piece 4, and since the plastic material peels off from the fixed side, it will shrink from the peeled side as it cools.
Thereafter, the whole is cooled and thinned, and the high precision of the surface 10 of the movable piece 8 is directly transferred to the molded product. Although not shown, the core pin 15, the runner ejecting pin 16, and the spool ejecting pin 17, each of which is slidably fitted into a hole drilled in the receiving plate 6, are actuated.
The optical reflection mirror 20 having a highly precise plane is released from the cavity 9 and the molded product is taken out.

In the above embodiment, the molded member (optical reflecting mirror) 2
Long grooves (deformation absorbing grooves) 21 and 22 formed on the back surface 24 of 0
Although one strip each was formed near the left and right side edges of the square shape, the present invention is not limited to this, and an appropriate number of strips may be formed in the direction in which warping is likely to occur.

For example, one groove may be formed near both vertical and horizontal edges of the molded member 20, and two grooves may be formed on each longitudinal edge and two grooves may be formed on each horizontal edge depending on the strength of the warp. This also includes forming one groove on each side edge of the groove.

(Second example) A second embodiment of the present invention will be explained with reference to FIGS. 4 and 5.

FIG. 4 is a plan view showing the shape of the back surface of a molded member according to a second embodiment of the present invention.

Figure 5 (a) (b) (C) (d) (el (f)
) (g) and (h) are plan views showing the shape of each back surface of the molded member according to the present invention.

A description will be given of different configurations of the molding molds made up of the stationary mold and the movable mold described in the first embodiment.

Lower end surface (molding part) 1 of fixed side piece 4 in cavity 9
8, that is, a long convex shape is formed near the inner vertical edge of the lower end surface 18 of the square corresponding to the molded member 20 shown in FIG.
A deformation absorbing protrusion of the same shape is formed between the lower end of the right side edge and the upper end of the left side edge of the long convex portion.

When the fixed side piece 4 formed in this way is molded, the back surface 24 of the optical reflection mirror 20 has an N shape as shown in FIG.
A deformation absorbing groove 25 in the shape of a letter is formed, and the optical reflecting mirror 2
It is possible to absorb distortion in both the vertical and horizontal directions when the warpage occurs at zero.

Further, as shown in FIG. 5(a), a U-shaped annular deformation absorbing groove 25 is formed on the back surface 24 of the optical reflection mirror 20.

In addition, as shown in FIG. 5, etc., the back surface 2 of the optical reflection mirror
4 is formed with a V-shaped deformation absorbing groove 25 (a combination of a plurality of linear shapes).

Further, as shown in FIG. 5(C), a circular (endless annular) deformation absorbing groove 25 is formed on the back surface 24 of the optical reflection mirror 20.

Further, as shown in FIG. 5(d), endless annular deformation absorbing grooves 25 are formed along the vicinity of the edges in four directions on the back surface 24 of the optical reflection mirror 20.

Also shown in box 5) is the back surface 2 of the optical reflection mirror 20.
4, a deformation absorbing groove 25 having a W-shaped ring shape with ends is formed.

Further, as shown in FIG. 5(b), deformation absorbing grooves 25 are formed on the back surface 24 of the optical reflection mirror 20, and are a combination of a plurality of semi-arched linear shapes.

Further, as shown in FIG. 5(g), N-shaped deformation absorbing grooves 25 are formed on the back surface 24 of the optical reflection mirror 20.

Furthermore, as shown in FIG. 5(5), deformation absorbing grooves 25, which are a combination of a plurality of rhombic linear shapes, are formed on the back surface 24 of the optical reflection mirror 20.

Each of the above-mentioned sides is provided in order to prevent deformation (warpage) in response to various warpages that occur in the optical reflection mirror 20, that is, warpage that occurs in the vertical or horizontal direction, or in both vertical and horizontal directions. This is a modification of the strain absorbing groove 25 shown in FIG.

(Third Embodiment) FIG. 6 is a perspective view showing a molded member according to a third embodiment of the present invention.

As shown in FIG. 6, in this embodiment, each reflective surface 23 of a plurality of optical reflective mirrors 20 is arranged inside,
Warp deformation due to distortion of the molded member (optical reflecting mirror) 20 formed in the vicinity of and along the ridge line 26 by matching one end edge surface of each and molding it into a roof-shaped shape (ridge line) 26 The groove 25 and the 25° are integrally molded to absorb the vibration.

As described above, the deformation absorbing grooves 25 and 25' provided along the ridgeline 26 can quickly cool the ridgeline 26 where heat tends to remain in the mold, and the structure of the plurality of optical reflection mirrors 20 can be quickly cooled. It is possible to maintain extremely stable corner accuracy.

In addition, deformation occurring on the surface away from the ridge line 26 is also caused by the deformation absorbing groove 2.
5 and 25 degrees, the angle up to the ridgeline 26 is not affected, so the angular accuracy of the ridgeline 26 can be kept stable.

(Fourth Embodiment) FIG. 7 is a perspective view showing a molded member according to a fourth embodiment of the present invention.

As shown in FIG. 7, a plurality of reflective mirrors 24 and a 24° reflective surface are arranged inside, and the ends thereof are slanted at 90° (an optical reflective surface formed to match the roof-shaped shape (ridgeline) 26). mirror 2
Warpage (deformation) prevention (absorption) grooves 25 and 25° are integrally molded in the vicinity of the ridgeline 26 of 0 (in the direction perpendicular to the 90° angle of both end edges of the roof mold).

As described above? To ensure the flatness of the entire surface by the absorption grooves 25 and 25° near both edges along the roof shape of the optical reflection mirror 20 formed by combining optical reflection mirrors of IE (IE), and to maintain the angle of the ridge line 26 with high precision. I can do it.

In the third and fourth embodiments described above, the deformation absorption groove 25 and the 25° angle are aligned with the ridgeline 26 of the optical reflection mirror 20.
Although the deformed absorption grooves 25 and 25' are formed along the roof shape of the optical reflecting mirror 20, or near both edges along the roof shape of the optical reflection mirror 20, the present invention is not limited thereto. Depending on the degree of deformation, it is also possible to use it in combination with the groove shapes shown in the first, second, and third embodiments. For example, it is easy to use the third embodiment and the fourth embodiment in combination. That is, the roof mold (
It is also easy to form an optical reflecting mirror 20, which is provided with absorption grooves 25 and 25° near the edge along the 90° angle.

Further, in each of the above embodiments, a Teflon coat with poor wettability was formed on the deformation absorbing protrusion on the fixed piece I8 and on the movable piece 10, but the present invention is not limited to this, and the pieces constituting the cavity 9 It also includes the provision of convex portions for forming absorption grooves on any of the surfaces that are likely to be deformed, and means for reducing wettability with the plastic material.

〔Effect of the invention〕

According to the present invention having the above configuration, by providing strain absorbing grooves on the back surface of the mirror corresponding to the mirror surface of the optical reflection mirror, improving wettability to the plastic material, and molding without applying holding pressure, It is highly effective to improve the surface precision and angle precision of a mirror structure consisting of a plane of an optical reflection mirror and a plurality of planes of optical reflection mirrors, and to provide it efficiently and at low cost.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a cross section from the side of a molding die for molding an optical reflection mirror according to the present invention. FIG. 2 is an enlarged cross-sectional plan view of the structure of the cavity shown in FIG. 1. FIG. 3(a) is a perspective view showing the back side of the optical reflection mirror according to the first embodiment of the present invention, which is molded by the mold shown in FIGS. 1 and 2. FIG. FIG. 3 (bl is a plan view showing a cross section taken along line A-A shown in FIG. 3(a). FIG. 4 is a perspective view showing the back side of an optical reflection mirror according to a second embodiment of the present invention. Fig. 5 (a) (b) (C) (d) (e) (f) (g)
(h) is a plan view showing the back side of each modified example of the optical reflection mirror according to the second embodiment. FIG. 6 is a perspective view showing the back side of an optical reflection mirror according to a third embodiment of the present invention. FIG. 7 is a perspective view showing the back side of an optical reflection mirror according to a fourth embodiment of the present invention. ■...Fixed side mounting plate 2...Fixed side template 3...Fixed side sleeve 4...Fixed side piece 5...Movable side template 6...Batch plate 7...Movable side Sleeve 8... Movable piece 9... Cavity lO... Movable piece surface (mirror surface) °11... Gate 12... Runner 13... Spool bush 14... Spool 15... - Core pin l6... Runner protruding bottle 17... Sprue protruding pin 18... Fixed side piece surface 19... Parting line 20... Molded member (optical reflective mirror) 21.22,2
5, 25°...Groove 23...Mirror surface 24...Mirror back surface 26...Ridge line

Claims (1)

[Claims] (1) An optical reflective mirror made of plastic, characterized in that a plurality of linear grooves for strain absorption or an annular groove with ends or ends are formed on the back surface of the mirror.