JP2006137179A - Injection-molded object - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a molded object with a microunevenness such as a light-proof line from becoming warped in injection molding. <P>SOLUTION: A mirror cylinder 20 has an extension part 22 which extends axially from one end side of a cylindrical part 21 of a cylindrical shape, and is molded by injection molding using a resin. Simultaneously with the injection molding of the cylinder 20, the light-proof line 23 of a continuous uneven shape is formed on the inner peripheral surface of the cylindrical part 21 and the inner peripheral surface of the extension part 22 which follows the former, while a false light-proof line 24 of a continuous uneven shape which extends, in the same direction, at the same interval and amplitude as the light-proof line 23. is formed on the outer peripheral surface of the extension part 22. The light-proof line 23 and the false light-proof line 24 are formed on the inner peripheral surface and the outer peripheral surface of the extension part 22 at the same time as the injection molding. Consequently, the resin temperature is distributed in almost the same condition on the inner peripheral side and the outer peripheral side of the extension part 22, and thus no difference in the molding shrinkage factor occurs. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin injection-molded product, and more particularly to an injection-molded product that can be applied to optical components such as a lens barrel and a finder in an optical apparatus such as a camera and a microscope.

Many optical components such as camera barrels and viewfinders are molded by resin injection molding, but the surface facing the optical path, such as the inner surface, of injection molded optical components is used to prevent light from reflecting off the surface. The light shielding lines are often formed at the same time.
As shown in FIG. 18, the light shielding line 1 is formed so as to periodically repeat a wavy uneven shape on one side of the optical component 2, and in the case of a camera component such as a lens barrel, The pitch is about 1 mm and the amplitude is about 0.3 mm.

When the uneven shape such as the shading line is formed simultaneously with the injection molding, deformation such as warpage due to the uneven shape may occur in the molded product (injection molded product).
19 and 20 explain the cause of this warpage. (A) is a cross-sectional view showing a mechanism in which warpage occurs due to a difference in resin temperature, and (b) is a characteristic diagram (graph). Yes, the vertical axis indicates the position in the thickness direction where the irregularities are formed, and the horizontal axis indicates the temperature.

  When the light shielding line 1 is deep as shown in FIG. 19A, the resin 3 has a large area in contact with the mold 4 in the vicinity of the light shielding line 1, so that the resin temperature at the contact portion is lowered. On the other hand, since the resin in the vicinity of the light shielding line 1 having a low temperature acts as a heat insulating material, the heat of the resin slightly inside the light shielding line 1 is hardly transmitted to the mold 4, and as a result, the temperature curve on the graph is , The temperature peak 5 becomes asymmetric. As shown in (b), the temperature of the part near the light shielding line 1 in the molded product is higher than the part of the center line 5 of the cavity. For this reason, the molding shrinkage rate in the vicinity of the light shielding line 1 becomes larger than the molding shrinkage rate in the vicinity of the side opposite to the light shielding line 1, and the upward warping indicated by the arrow A occurs in the molded product.

  As shown in FIG. 20 (a), when the light shielding line 1 is shallow, the area where the resin 3 contacts the mold 4 is large in the vicinity of the light shielding line 1 as in FIG. 19 (a). Becomes lower. However, since the light shielding line 1 is shallow, the low-temperature resin that acts as a heat insulating material is less in amount than the situation of FIG. 19A and is distributed around the cavity. Therefore, it is less likely that the heat of the resin slightly inside the light shielding line 1 is prevented from being conducted to the mold. For this reason, the heat of the resin is more easily transmitted to the mold 4 on the light shielding line 1 side in the molded product than on the opposite side, and as shown in FIG. The temperature near 1 is lower. For this reason, the molding shrinkage rate in the vicinity of the side opposite to the light shielding line 1 becomes larger than the molding shrinkage rate in the vicinity of the light shielding line 1, and the downward warping indicated by the arrow B occurs in the molded product.

In contrast to the warp as described above, Japanese Patent Laid-Open No. 2002-36309 controls the resin temperature distribution by providing a temperature difference between the fixed mold and the movable mold. In JP-A-6-55597, the resin temperature is controlled between the vicinity of the gate and the flow end portion of the resin.
JP 2002-36309 A JP-A-6-55597

  However, the methods disclosed in JP-A-2002-36309 and JP-A-6-55597 provide a temperature difference with respect to the mold, and provide a temperature difference when the molded product has a complicated shape. Have difficult problems. In addition, for minute uneven shapes such as light-shielding lines, the temperature distribution cannot be controlled in the thickness direction of the molded product, so that the occurrence of warpage cannot be effectively prevented. Yes.

  The present invention has been made in consideration of such problems, and even when it has minute irregularities such as light shielding lines, the molded product does not warp and has a good shape. It is an object of the present invention to provide an injection molded product that can be used.

  The injection molded product of the invention according to claim 1 has a plurality of concave and convex shapes formed on the surface of the molded product molded by resin injection, and a plurality of concave and convex shapes corresponding to the concave and convex shapes are formed on the back surface of the surface. It is characterized by.

  The invention according to claim 2 is the injection-molded product according to claim 1, wherein the molded product has a cylindrical portion, and the surface and the back surface thereof are provided in the cylindrical portion. .

  The invention according to claim 3 is the injection molded product according to claim 1, wherein the molded product has a planar shape portion, and the surface and the back surface thereof are provided in the planar shape portion. .

  A fourth aspect of the present invention is the injection molded product according to the first to third aspects, wherein the surface and the back surface thereof are cantilever portions.

  A fifth aspect of the present invention is the injection molded product according to the first to third aspects, wherein the surface and the back surface thereof are doubly supported beam portions.

  A sixth aspect of the present invention is the injection molded product according to the first to fifth aspects of the present invention, and is characterized by a wave shape having a pitch shifted between the uneven surface and the back surface thereof.

  The injection molded product of the invention according to claim 7 is an injection molded product molded by resin injection, wherein the first region which is a partial region of the injection molded product and the other partial region of the injection molded product. A second region, and the second region projects continuously from the first region in a beam shape, and a plurality of irregularities are repeatedly formed on both sides of the second region. It is characterized by.

  The invention according to claim 8 is an injection molded product molded by resin injection, wherein a first region which is a partial region of the injection molded product and a second region which is another partial region of the injection molded product. The second region is surrounded by the first region, and a plurality of irregularities are repeatedly formed on both surfaces of the second region. .

  A ninth aspect of the present invention is the injection molded product according to the seventh to eighth aspects, wherein the plurality of irregularities on both surfaces of the second region have the same shape.

  The invention according to claim 10 is the injection-molded article according to claims 7 to 9, characterized in that the shape of the unevenness is a wave shape with a pitch shifted between one surface and the back surface thereof. The said surface to perform and the back surface are cantilever parts, It is characterized by the above-mentioned.

  An eleventh aspect of the invention is an injection-molded article according to the seventh to tenth aspects, wherein the first region has a cylindrical shape.

  A twelfth aspect of the present invention is the injection-molded article according to the seventh to eleventh aspects, wherein the one surface provided with the plurality of irregularities is a light shielding line.

  A thirteenth aspect of the invention is an injection-molded article according to the seventh to twelfth aspects, wherein the second region is formed to extend in a flat plate shape.

  A fourteenth aspect of the invention is an injection-molded article according to the seventh to thirteenth aspects, wherein the second region has a cylindrical surface.

  The invention according to claim 15 is the injection-molded article according to claims 7 and 9 to 13, including a cylindrical portion, wherein the first region is the cylindrical portion, and the second region is the It is a cantilever-like portion protruding from a cylindrical portion.

  A sixteenth aspect of the present invention is the injection-molded article according to the fifteenth aspect, wherein the cantilevered portion of the second region projects in a plate shape.

  The invention according to claim 17 is the injection-molded article according to claim 15, wherein the cantilever portion has a cross section on an arc.

  The invention according to claim 18 is the injection-molded article according to claim 8, wherein the second region is separated from the first region by a pair of elongated holes on both sides and is provided in a doubly supported beam shape. It is characterized by.

  The invention according to claim 19 is the injection-molded product according to claim 18, wherein the injection-molded product further includes a cylindrical portion, the first region is the cylindrical portion, and the second The region is characterized in that it is provided in the form of a cantilever beam in the cylindrical part.

  The invention according to claim 20 is characterized in that a plurality of uneven shapes are formed on the surface of a U-shaped molded product formed by resin injection, and the plurality of uneven shapes corresponding to the uneven shapes are formed on the back surface of the surface. It is formed.

  A twenty-first aspect of the invention is the injection-molded article according to the twentieth aspect, wherein the molded article is rectangular and has a flat plate-like bottom surface portion and a pair protruding in parallel with each other from the bottom surface portion and at right angles from the bottom surface portion. A plurality of concave and convex shapes are respectively formed in the direction perpendicular to the longitudinal axis on the inner surface and the outer surface of the bottom surface portion and the side wall portion. And

  According to the present invention, the temperature distribution of the resin on the surface at the time of injection molding and the back surface thereof becomes substantially symmetrical, and the resin shrinks evenly. For this reason, there is little warp etc. and a good-shaped injection-molded article is obtained. This also eliminates the need to complicate a mold for resin injection molding and to complicate a molding apparatus in order to prevent warping.

  That is, in the invention according to claim 1, in addition to the formation of the concavo-convex shape on the surface of the injection-molded molded product, the concavo-convex shape is formed on the back surface thereof, so that the injection molding into the mold is performed. Since the temperature distribution of the resin on the surface and the back surface thereof is substantially symmetrical, a difference in the shrinkage rate of the resin during molding does not occur on the surface and the back surface thereof. For this reason, deformation such as warpage does not occur, and an injection-molded article having a good shape can be obtained.

  In the inventions of claims 2 and 3, even if the molded product has a cylindrical portion or a planar shape portion, the cylindrical shape portion or the planar shape portion does not warp. Is obtained.

  In the inventions according to the fourth and fifth aspects, since the surface and the back surface thereof are provided on the cantilever portion or the both-end cantilever portion, the warp does not occur in these portions, and a good injection molded product can be obtained.

  In the invention described in claim 6, the wavy pitch in the concavo-convex shape is shifted, whereby the thickness of the surface and the back surface thereof can be ensured, and the moldability can be improved.

  According to the seventh and eighth aspects of the present invention, a plurality of irregularities are repeatedly formed on both surfaces of the second region continuously projecting from the first region in the form of a beam, and warpage occurs in the second region. Therefore, a good injection molded product can be obtained. A difference in resin shrinkage during molding does not occur on both sides of the second region. For this reason, deformation such as warpage does not occur, and an injection-molded article having a good shape can be obtained.

  In the invention according to claim 9, since the plurality of irregularities on both surfaces of the second region have the same shape, the resin temperature distribution inside the injection-molded product is substantially symmetrical, and there is no difference in the resin molding shrinkage rate. . Therefore, a warp does not occur in the second region, and a good injection molded product can be obtained.

  In the invention described in claim 10, the wavy pitch in the concavo-convex shape is shifted, whereby the thickness of the surface and the back surface thereof can be secured, and the moldability can be improved.

  In the invention described in claim 11, even if the first region is cylindrical, no warpage occurs in the cylindrical first region, so that a good injection molded product can be obtained.

  In the invention of claim 12, since one surface provided with a plurality of irregularities is a light shielding line, reflection of light on the surface can be prevented.

  In the invention described in claim 13, warpage does not occur even in the second region extending in a flat plate shape, and a good injection molded product can be obtained.

  In the invention described in claim 14, since the warp does not occur even in the second region having the cylindrical surface, a good injection molded product can be obtained.

  According to the fifteenth aspect of the present invention, no warp occurs in any of the first region of the cylindrical portion and the second region of the cantilevered portion, so that a good injection molded product can be obtained.

  In the invention described in claim 16, since the warp does not occur in the second region of the cantilever-like portion projecting in a plate shape, a good injection molded product can be obtained.

  In the invention according to claim 17, since the warp does not occur in the second region of the cantilevered portion in the arc-shaped cross section, a good injection molded product can be obtained.

  In the invention described in claim 18, since a warp does not occur in the second region of the cantilever beam separated from the first region by a pair of elongated holes on both sides, a good injection molded product can be obtained. .

  In the invention according to claim 19, the injection-molded product includes a cylindrical portion, and warpage occurs in both the first region of the cylindrical portion and the second region of the cantilever beam in the cylindrical portion. Therefore, a good injection molded product can be obtained.

  In the invention according to claim 20, in addition to the formation of the concavo-convex shape on the surface of the injection-molded U-shaped molded product, the concavo-convex shape is formed on the back surface thereof, so that the mold is formed. Since the temperature distribution of the resin on the surface and the back surface thereof during injection molding is substantially symmetrical, a difference in the shrinkage of the resin during molding does not occur on the surface and the back surface thereof. For this reason, deformation such as warpage does not occur, and an injection-molded article having a good shape can be obtained.

  In the invention of claim 21, a plurality of irregularities are respectively formed on the inner side surface and the outer side surface of the bottom surface portion and the side wall portion, and warpage does not occur in either the bottom surface portion or the side wall portion. An injection molded product is obtained.

  Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. In each embodiment, the same member is assigned the same reference numeral.

  In the present invention, a plurality of uneven shapes that are periodically repeated are formed on a surface (surface) of a molded product that is molded by resin injection molding, and a plurality of uneven shapes that are periodically repeated corresponding to the uneven shape. Is formed on the back surface. The uneven shape on the front surface and the back surface thereof is formed simultaneously with the injection molding of the molded product. 1 to 3 show respective forms in Embodiment 1 of the present invention. In these forms, the molded product to be injection-molded has a flat plate shape, and a plurality of concave and convex shapes are formed on both sides thereof.

  In the first mode of the first embodiment of the present invention shown in FIG. 1 (FIGS. 1A to 1C), the upper surface 11a which is the first surface of the flat molded product (injection molded product) 11 is formed. A plurality of periodically repeated irregularities 12 are formed so as to be continuous in the length direction, and a plurality of periodically repeated irregularities 12 corresponding to the irregularities 12 on the upper surface are formed on the lower surface 11b as the second surface. The concavo-convex shape 13 is formed so as to be continuous in the length direction. The molded product 11 is formed by injection molding a thermoplastic resin, and the concavo-convex shapes 12 and 13 are formed simultaneously with the injection molding of the molded product 11.

  The concavo-convex shapes 12 and 13 on the upper and lower surfaces are formed so that peaks and troughs are alternately continued and extend in the same direction, and are the same concavo-convex shapes 12 and 13. These concavo-convex shapes 12 and 13 correspond to light shielding lines of the optical component. Thus, by forming the same uneven shapes 12 and 13 on the upper and lower surfaces of the molded product 11, the resin temperature distribution inside the molded product 11 when the resin is injection-molded into the mold is the front side and the back side. Therefore, there is no difference in resin molding shrinkage. Thereby, warp does not occur in the molded product 11 and a good molded product 11 is obtained.

  Also in another form (second form) of Example 1 in FIG. 2 (FIGS. 2A to 2C), the upper surface 11a and the upper surface 11a, which are the first surfaces of the flat molded article 11, are shown. A plurality of concave and convex shapes 12 and 14 are formed on the lower surface 11b which is the back surface of the first and second surfaces. In the second embodiment, the plurality of uneven shapes 14 on the lower surface 11b are formed in a direction orthogonal to the plurality of uneven shapes 12 on the upper surface 11a. That is, the crests and troughs in the concavo-convex shape 14 of the lower surface 11b extend in the orthogonal direction with respect to the direction in which the crests and troughs in the concavo-convex shape 12 of the upper surface 11a extend. As described above, even if the concavo-convex shapes 12 and 14 extend in different directions, the resin temperature distribution inside the molded product 11 is substantially the same on the front surface side and the back surface side, so that a difference in the resin molding shrinkage ratio occurs. There is no warpage in the molded product 11.

  In this case, in the first embodiment shown in FIG. 1, since the directions restrained by the mold when the resin undergoes molding shrinkage are the same on the upper surface 11a and the lower surface 11b, the molding shrinkage rate of polyacetal resin, polyethylene, etc. It is preferable to apply to a large crystalline resin. On the other hand, in the 2nd form shown in FIG. 2, it is preferable to apply to amorphous resin with a comparatively small mold shrinkage rate, such as polycarbonate resin and ABS resin. Needless to say, the first embodiment shown in FIG. 1 may be applied even to an amorphous resin, or the second embodiment shown in FIG. 2 may be applied to a crystalline resin.

  In the third mode in Example 1 of FIG. 3 (FIGS. 3A to 3D), the concavo-convex shapes 15 and 16 are formed of cross stitches continuous with the upper surface 11a and the lower surface 11b of the flat plate-shaped molded article 11. Is formed. The concavo-convex shapes 15 and 16 are formed by continuously forming minute quadrangular pyramids in the XY direction with respect to the upper and lower surfaces 11a and 11b, and the upper and lower surfaces 11a and 11b have the same concavo-convex shape. . Thereby, since the resin temperature distribution inside the molded product 11 becomes substantially the same on the front surface side and the back surface side, there is no difference in molding shrinkage of the resin, and the molded product 11 is not warped.

  The concavo-convex shape formed on one surface of the molded product 11 and the concavo-convex shape formed on the back surface corresponding thereto are not limited to the above shapes, and dimples, threads, and other shapes having continuous spherical concavo-convex shapes. Even in this case, it is possible to similarly prevent the occurrence of warpage of the molded product.

  FIG. 4 shows a second embodiment of the present invention applied to the lens barrel 20 of the camera.

  The lens barrel (molded product) 20 includes a cylindrical tube portion 21 to which a plurality of lenses are inserted and fixed, and an extension portion of an arc-shaped cross section in a cross section orthogonal to an axis extending in the axial direction from one end side of the tube portion 21. 22 and is formed by resin injection molding. The extension part 22 extends integrally from the cylinder part 21 so as to be divided into three equal positions on the circumference, and is a cantilever part with respect to the cylinder part 21. On the inner peripheral surface of the cylindrical portion 21 and the inner peripheral surface of the extension portion 22 subsequent thereto, a light shielding line 23 as a continuous uneven shape is formed. This prevents light from being reflected from the inner periphery of the cylinder portion 21. The light shielding line 23 is formed to have a wave shape with a pitch of about 1 mm and an amplitude of about 0.3 mm, for example.

  The outer peripheral surface of each extension portion 22 in the lens barrel 20 is a back surface of the inner peripheral surface of the portion 22, and a pseudo light-shielding line 24 corresponding to the light-shielding line 23 is formed on each outer peripheral surface. Yes. The pseudo light-shielding lines 24 are formed to have the same pitch and amplitude as the light-shielding lines 23 and extend in the same direction. Such light shielding lines 23 and pseudo light shielding lines 24 are formed simultaneously with the injection molding of the lens barrel 20.

  Thus, simultaneously with the injection molding of the lens barrel 20, the light shielding line 23 is formed on the inner peripheral surface of each extension portion 22 and the pseudo light shielding line 24 is formed on the outer peripheral surface. Since the inner peripheral side and the outer peripheral side are substantially the same, there is no difference in the resin molding shrinkage rate, and no warpage occurs in the extension portion 22 having a cylindrical surface and having an arcuate cross section. In particular, in Example 2, since the extension 22 is a cantilever portion projecting in a plate shape, warping is likely to occur during injection molding, but the pseudo-light-shielding corresponding to the light-shielding line 23 is thus obtained. By forming the line 24, it is possible to prevent warpage at the extended portion 22 of the cantilever portion protruding in a plate shape. That is, not only the cylindrical portion 21 but also the cantilever-like extension portion 22 is not warped, and a good lens barrel 20 without warping can be obtained.

  FIG. 5 shows a lens barrel 20A having a conventional configuration in which the pseudo light-shielding line 24 is not formed in the extension portion 22 with respect to the second embodiment. In this case, the direction of the arrow C or the direction opposite to the arrow C is shown. This causes a problem that warpage occurs and assembly with another lens barrel that fits into the lens barrel 20A is impossible.

  6 (a) to 6 (b) show a third embodiment of the present invention applied to the finder frame 30 of the camera.

  The finder frame (molded product) 30 is composed of a frame body 31 having a U-shaped cross section, and a light shielding line 33 is formed on the inner surface thereof. The frame 31 has a pair of opposed pieces 32, and one of the opposed pieces 32 has a horizontally long opening 35. The opening 35 is formed so as to be positioned at the intermediate portion in the height direction of the facing piece 32, and the end (upper end) 32 a on the free side of the opening 35 in the facing piece 32 is a doubly supported beam portion. Even if it is, it becomes a region where warpage is likely to occur.

  The light shielding line 33 is formed on the entire inner surface of the opposing piece 32, and thus the light shielding line 33 is also formed on the upper end portion 32a. In the third embodiment, a pseudo light shielding line 34 is formed on the outer surface which is the back surface of the inner surface of the facing piece 32. The pseudo light shielding line 34 corresponds to the light shielding line 33 on the inner surface side, and is formed to extend in the same direction with the same pitch and amplitude as the light shielding line 33. The pseudo light-shielding line 34 is formed on the outer surface of the upper end portion 32 a of the facing piece 32.

  In this way, by forming the pseudo light-shielding line 34 on the outer surface of the upper end portion 32a of the facing piece 32 corresponding to the light shielding line 33 on the inner surface side of the facing piece 32, the upper end portion 32a of the facing piece has the inner and outer surfaces thereof. Corrugated shapes are formed correspondingly. For this reason, the resin temperature distribution in the upper end portion 32a becomes substantially the same on the inner surface side and the outer surface side, and a difference in molding shrinkage of the resin does not occur. Therefore, since both sides are in the form of a cantilever beam separated from the frame body 31 by a pair of long holes (opening 35), the warp is prevented from occurring even in the upper end portion 32a where warpage is likely to occur, and a finder having a good shape is obtained. A frame 30 is obtained.

  FIG. 7 shows a finder frame 30A having a conventional configuration in which the pseudo light-shielding line 34 is not formed on the upper end portion 32a with respect to the third embodiment. In this case, the upper end portion 32a is warped. It becomes a defective product.

  FIGS. 8A, 8B and 9 show a fourth embodiment applied to a lens frame 40 which is a kind of lens barrel part of a camera.

  The lens frame (molded product) 40 of Example 4 includes a ring-shaped lens insertion frame 41 into which a lens is inserted and fixed, a leg portion 43 extending from the lens insertion frame 41 in the optical axis direction, and a leg portion 43. The cam floor 44 is formed and engaged with a cam of another lens barrel, and these are integrally formed by injection molding of resin.

  The leg portion 43 is a cantilever portion with respect to the lens insertion frame 41 by extending from the lens insertion frame 41 and having an extended end portion as a free end. In the fourth embodiment, a light shielding line 46 is formed on a part of the inner surface which is the surface on the optical axis side of the leg portion 43. The light shielding line 46 has a plurality of minute wave shapes traversing the leg portion 43. In addition, a pseudo light-shielding line 47 of the same shape corresponding to the light-shielding line 46 is formed on a part of the outer peripheral surface of the leg portion 43. The pseudo light-shielding line 47 is formed on the outer surface which is the back surface of the inner surface of the leg portion 43, and is formed in the same shape as the light-shielding line 46 on the inner surface.

  By forming the light shielding lines 46 and the pseudo light shielding lines 47 on both surfaces of the leg portion 43 in this way, the resin temperature distribution in the leg portion 43 becomes substantially the same on the inner surface side and the outer surface side, and the difference in the resin molding shrinkage rate is reduced. It will not occur, and the leg 43 will not be warped. Therefore, even when it is a cantilever portion and warpage is likely to occur, the warpage can be effectively prevented.

  FIGS. 10A, 10B, and 11 show a lens frame 40A having a conventional configuration in which the pseudo light-shielding line 47 is not formed on the leg 43 with respect to the fourth embodiment. In this case, FIG. Since the concave / convex shape is formed only on the inner surface of the leg portion 43 and the outer surface is flat, the molding shrinkage rate of the resin differs between the inner and outer surfaces and warping occurs in the radial direction of the leg portion 43, resulting in defective parts. .

  12 and 13 show the second and third modes of the fourth embodiment. In the second form of FIG. 12, the pitch of the pseudo light shielding lines 47 formed on the outer surface is shifted from the light shielding lines 46 formed on the inner surface of the legs 43. That is, the light shielding line 46 and the pseudo light shielding line 47 are formed by continuing a minute wave shape, but the valley part 47b of the pseudo light shielding line 47 corresponds to the peak part 46a of the light shielding line 46, and the light shielding line 46 The light shielding lines 46 and the pseudo light shielding lines 47 are formed so as to be relatively displaced at a 1/2 pitch so that the peak portions 47a of the pseudo light shielding lines 47 correspond to the valleys 46b.

  Thus, by shifting the pitch of the light shielding lines 46 and the pseudo light shielding lines 47, it is possible to ensure the thickness of the leg portions 43. That is, in the first mode of the fourth embodiment shown in FIG. 9, the pitches of the light shielding lines 46 and the pseudo light shielding lines 47 coincide with each other. In this case, the thickness of the base portion of the leg 43 is 1.0 mm. When the angle of the crest and trough is 90 ° and the pitch is 0.4 mm, the thickness of the leg 43 is 0.6 mm, because a thin part of 0.6 mm is formed. Formability is somewhat inferior. On the other hand, in the 2nd form of FIG. 12, since the thickness of the leg part 43 will be 0.8 mm on the same conditions as the above, thickness can be ensured and a moldability can be improved.

  In the form of FIG. 13, in addition to the form of FIG. 2, the inner and outer light shielding lines 46 and the pseudo light shielding lines 47 are formed so as to ensure the thickness of the base part of the leg part 43. Thereby, the thickness of the formation part of the light shielding line 46 and the pseudo | simulated light shielding line 47 can be 1.0 mm, and it becomes possible to further improve a moldability.

  FIG. 14 shows a fifth embodiment applied to the lens barrel 50 of the camera of the present invention.

  The lens barrel 50 has a cylindrical shape as a whole, and long grooves 51 along the axial direction for positioning a lens inserted therein are formed at six locations on the circumference. The long grooves 51 form a pair of two adjacent grooves, and a bridging portion 52 is formed between the long grooves 51 that form a pair, and the bridging portion 52 becomes a doubly supported beam-like portion in the cylindrical portion. ing. The long groove 51 may extend in a direction other than the axial direction such as a circumferential direction or an oblique direction.

  A light shielding line 53 is formed on the inner peripheral surface facing the optical axis of the lens barrel 50. In addition to this, a pseudo light-shielding line 54 similar to the light-shielding line 53 is formed on the outer peripheral surface which is the back surface of the inner peripheral surface. The light shielding line 53 and the pseudo light shielding line 54 are also formed in the bridge portion 52 having a doubly supported beam shape. Thus, by forming the pseudo light-shielding line 54 corresponding to the light-shielding line 53, the resin temperature distribution becomes substantially the same at the inner peripheral part (inner peripheral face) and the outer peripheral part (outer peripheral face), and the molding shrinkage rate of the resin No difference occurs. Therefore, warp does not occur in any of the cylindrical barrel 50 and the doubly-supported bridge portion 52 in the barrel 50, and a good barrel 50 without warp is obtained.

  FIG. 15 shows a second mode of the fifth embodiment. In the second embodiment, the pseudo light shielding line 54 is formed on the outer surface of the bridging portion 52 sandwiched between the long grooves 51 that form a pair, and the pseudo light shielding line 54 is formed on the other part of the outer surface of the lens barrel 50. Is not formed. Since the bridging portion 52 is a both-sided ridge portion sandwiched between the adjacent long grooves 51, the bridging portion 52 is likely to warp during injection molding, but the pseudo light-shielding line 54 is provided on the outer surface of the bridging portion 52. The formation of warpage can be prevented by forming. Therefore, in such a form, since the range which processes the formation site | part for forming the pseudo light-shielding line 54 to the metal mold | die for injection molding becomes small, the man-hour and cost of metal mold | die preparation can be reduced.

  FIG. 16 shows a sixth embodiment of the present invention. The sixth embodiment is applied to a finder frame of a camera.

  The finder frame (molded product) 60 is a U-shaped part molded from a synthetic resin, and the finder frame 60 has a rectangular and flat bottom portion 60a so as to surround the optical axis O. A pair of flat side wall portions 60b projecting from the bottom surface portion 60a in parallel with each other at a right angle from the bottom surface portion 60a are formed. A plurality of light shielding lines 63 and 64 are provided on the inner and outer surfaces of the bottom surface portion 60a and the side wall portion 60b, respectively, in the direction perpendicular to the optical axis as described above.

  Specifically, a light-shielding line 63a is provided on the U-shaped inner surface that is one surface of the bottom surface portion 60a, and a pseudo-light-shielding line 64a is provided on the outer surface that is the back surface thereof, and the side wall portion 60b. The U-shaped inner side surface is provided with a light shielding line 63b, and the back side thereof is provided with a pseudo light shielding line 64b.

  By doing so, the resin temperature distribution inside the molded product 60 when the resin is injection-molded into the mold is substantially symmetric between the front surface side and the back surface side, so that there is no difference in the resin molding shrinkage rate. . Therefore, the bottom surface portion 60a does not warp, and the flat side wall portion 60b protruding at a right angle from the bottom surface portion does not warp itself and does not tilt with respect to the bottom surface portion 60a. Can be injection molded.

  FIG. 17A shows a finder frame 60 </ b> A having a conventional configuration composed of a U-shaped part for the sixth embodiment. The light shielding line 63Aa is provided on the inner surface side of the bottom surface portion 60Aa of the finder frame 60A, and the light shielding line 63Ab is merely provided on the inner surface of the side wall portion 60Ab. That is, the conventional finder frame 60A is not provided with the pseudo light shielding line 64a on the outer surface of the bottom surface portion 60Aa and the pseudo light shielding line 64b on the outer surface of the side wall portion 60Ab.

  In this conventional configuration, as shown in FIG. 17B as an example, the finder frame 60A can be seen from the direction indicated by the arrow E (optical axis direction), which is the direction in which the light shielding lines are arranged, and the finder frame after injection molding As shown in FIG. 17B, the shape of 60A is warped and deformed so that the bottom surface 60Aa is convex as indicated by a two-dot chain line. Accordingly, the side wall portion 60Ab falls due to deformation of only the bottom surface portion 60Aa, and the side wall portion 60Ab itself is warped and deformed so that the outer surface becomes convex. That is, it is difficult to obtain a desired shape with such a conventional configuration.

  In addition, the 1st area | region which is a partial area | region of the injection-molded product in a claim, and the 2nd area | region which is another partial area | region of an injection-molded product are the cylinders of the lens-barrel 20 in FIG. The part 21 corresponds to the first region, and the extension 22 of the lens barrel 20 corresponds to the second region. In FIG. 6, the frame body 31 of the finder frame 30 corresponds to the first region, and the pair of opposed pieces 32 corresponds to the second region. In FIG. 8, the lens insertion frame 41 of the lens frame 40 corresponds to the first region, and the leg portion 43 corresponds to the second region. In FIG. 14, the lens barrel 50 of the cylindrical portion corresponds to the first region, and the bridging portion 52 corresponds to the second region.

(A), (b), (c) is the perspective view, front view, and side view which show the 1st form in Example 1 of this invention. (A), (b), (c) is the perspective view, front view, and side view which show the 2nd form in Example 1 of this invention. (A), (b), (c), (d) is the perspective view, front view, side view, and top view which show the 3rd form in Example 1 of this invention. It is a perspective view which shows Example 2 of this invention. 10 is a perspective view showing a conventional configuration corresponding to Example 2. FIG. (A), (b) is the perspective view and D arrow side view which show Example 3 of this invention. (A), (b) is the perspective view and D arrow side view which show the conventional structure corresponding to Example 3. FIG. (A), (b) is the perspective view which shows Example 4 of this invention, and the perspective view from a back surface. It is sectional drawing of the leg part of FIG. (A), (b) is the perspective view which shows the conventional structure corresponding to Example 4, and the perspective view from a back surface. It is sectional drawing of the leg part of FIG. It is a perspective view which shows the 2nd form of Example 4. FIG. It is a perspective view which shows the 3rd form of Example 4. FIG. It is a perspective view which shows Example 5 of this invention. It is a perspective view which shows the 2nd form of Example 5. FIG. It is a perspective view which shows Example 6 of this invention. (A), (b) is the perspective view and E side view which show the conventional structure corresponding to Example 6. FIG. (A), (b) is the perspective view and front view of the conventional molded product which formed uneven | corrugated shape. (A), (b) is sectional drawing and the characteristic view which show the mechanism in which curvature generate | occur | produces. (A), (b) is sectional drawing and the characteristic view which show the mechanism in which curvature generate | occur | produces.

Explanation of symbols

11 Molded products (injection molded products)
12, 13, 14, 15, 16 Uneven shape 20, 40, 50 Lens barrel (molded product)
23, 33, 46, 53, 63a, 63b Shading line 24, 34, 47, 54, 64a, 64b Pseudo shading line 30, 60 Finder frame (molded product)

Claims (21)

  An injection-molded product, wherein a plurality of uneven shapes are formed on a surface of a molded product formed by resin injection, and a plurality of uneven shapes corresponding to the uneven shapes are formed on the back surface of the surface.   The injection-molded article according to claim 1, wherein the molded article has a cylindrical portion, and the surface and the back surface thereof are provided in the cylindrical portion.   The injection-molded product according to claim 1, wherein the molded product has a planar shape portion, and the surface and the back surface thereof are provided in the planar shape portion.   The injection molded product according to claim 1, wherein the surface and the back surface thereof are cantilever portions.   The injection molded product according to claim 1, wherein the surface and the back surface thereof are both-end supported beam portions.   6. The injection-molded product according to claim 1, wherein the uneven shape has a wave shape with a pitch shifted between the surface and the back surface thereof. In injection molded products molded by resin injection,
A first region which is a partial region of the injection molded product;
A second region which is another partial region of the injection molded product,
The injection molded product, wherein the second region projects continuously from the first region in a beam shape, and a plurality of irregularities are repeatedly formed on both surfaces of the second region. In injection molded products molded by resin injection,
A first region which is a partial region of the injection molded product;
A second region which is another partial region of the injection molded product,
The injection-molded article, wherein the second region is surrounded by the first region, and a plurality of irregularities are repeatedly formed on both surfaces of the second region.   9. The injection-molded product according to claim 7, wherein the plurality of irregularities on both surfaces of the second region have the same shape.   The injection-molded article according to any one of claims 7 to 9, wherein the uneven shape is a wave shape with a pitch shifted between one surface and the back surface thereof.   The injection-molded article according to claim 7, wherein the first region has a cylindrical shape.   The injection molded product according to claim 7, wherein one surface provided with the plurality of irregularities is a light shielding line.   The injection molded product according to claim 7, wherein the second region is formed to extend in a flat plate shape.   The injection molded product according to claim 7, wherein the second region has a cylindrical surface.   The injection-molded article includes a cylindrical portion, wherein the first region is the cylindrical portion, and the second region is a cantilever portion protruding from the cylindrical portion. The injection molded product according to claim 7, 9 to 13.   The injection-molded article according to claim 15, wherein the cantilever-like portion of the second region projects in a plate shape.   The injection-molded article according to claim 15, wherein the cantilevered portion has an arc-shaped cross section.   9. The injection-molded product according to claim 8, wherein the second region is provided in a doubly supported beam shape on both sides separated from the first region by a pair of elongated holes.   The injection-molded product includes a cylindrical part, the first region is the cylindrical part, and the second region is provided in a doubly supported beam shape in the cylindrical part. The injection-molded article according to claim 18.   A plurality of concavo-convex shapes are formed on the surface of a U-shaped molded product formed by resin injection, and a plurality of concavo-convex shapes corresponding to the concavo-convex shapes are formed on the back surface of the surface. Injection molded products. The molded product is formed to have a rectangular and flat bottom portion and a pair of flat side wall portions projecting at right angles from the bottom portion in parallel to the bottom portion. 21. The injection-molded product according to claim 20, wherein a plurality of concave and convex shapes are formed on the inner side surface and the outer side surface in a direction perpendicular to the longitudinal axis.

Images