JP2005254660A - Mold for molding and molded component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide surely and simply a marking having information on histories or the like of a molded component and a mold for molding on the molded component simultaneously with molding of the molded component. <P>SOLUTION: A plurality of processed marks consisting of a surface roughness more rougher than the surface roughness of the molded surface and with 5,000 nm or less are arranged so as to express marks, characters or the like on the molding face of the mold for molding, for molding the molded component from a glass material or a resin material. The marking parts such as marks and characters made by the processing marks on the mold are transferred on the molded component molded by the mold, to give the information to the marking parts. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a molded part for optics used in a digital versatile disk apparatus, an optical recording / reproducing apparatus for a computer, for example, a molded part such as an objective lens used for recording or reproducing information on an optical disk, and a molding die thereof. Is.

  Conventionally, for example, an optical component used in a digital versatile disk device, an optical recording / reproducing device for a computer, for example, an objective lens is manufactured from a glass material or a resin material by a molding die. It is known that astigmatism occurs in a lens molded by this molding die due to various conditions such as accuracy of the molding die, pressurizing conditions, and heating temperature.

  As described above, the aberration generated in the lens ignores this, and if it is incorporated in the optical pickup device, it affects the optical performance. Therefore, it is necessary to adjust the installation position in the optical pickup device. A mark indicating the direction of astigmatism is provided on the outside of the surface.

  As a method of attaching this marking to a lens, as disclosed in Patent Document 1, a method of marking one by one by an inkjet printer or the like after molding of a lens, for example, as disclosed in Patent Document 2, By roughing the flat part around the molding die by irradiating it with an electron beam, or by forming a concave slow-thickness part or convex part, There is a method in which convex or concave marks are transferred.

However, the method of marking one by one after molding the lens requires a marking process and requires time to dry the ink after marking, which is one of the causes of increasing the manufacturing cost of the lens. Yes. In addition, it is possible to determine the direction of astigmatism from the position of the marking by simply roughing the molding die or forming a simple recess or projection and transferring this to the lens, For example, it is not possible to know a history or the like necessary when investigating for improving the quality of a lens, for example, from lens defect analysis or production quantity management.
JP 2003-114307 A Japanese Patent No. 3204031

  According to the present invention, a molding part is formed by providing a plurality of fine processing marks in advance on a transfer surface of a limited area of a molding die and arranging the processing marks so that symbols or characters are formed. At the same time, marking having information such as the history of the molded part and the molding die is surely and easily applied to the molded part.

  The present invention relates to a molding die for molding a molded part such as a lens from a glass material or a resin material, and a plurality of surface roughnesses that are rougher than the surface roughness of the molding transfer surface and less than or equal to 5000 nm in advance. By arranging the machining traces to represent symbols or characters and molding the molded part with this molding die, the machining traces are transferred to the molded parts to have information by symbols or letters etc. Is.

  According to the present invention, a marking part having information can be added to a molded part by arranging a plurality of processing marks on the molding die in advance so as to represent symbols or characters. It is possible to know the history of the molded part from the information held in the marking part at the time of inspection such as defect analysis or production quantity management. Therefore, for example, molding accuracy etc. for molded parts molded with the same molding die When a problem occurs, it is easy to distinguish a molded part of the same marking part by looking at the marking part of the molded part and take measures against it.

  Further, when the molded part is made of, for example, a lens, the marking portion is also used as a mark indicating the lens mounting direction, so that the convenience during assembly is good and the effect is great.

(Example 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.

  1A and 1B show an optical element in Example 1 of the present invention, where FIG. 1A is a side view, FIG. 1B is a bottom view, FIG. 1C is a top view of a marking portion, and FIG. It is sectional drawing. 2 shows a molding block in Example 1 of the present invention, (a) is a schematic sectional view, (b) is a perspective view of the lower mold, and FIG. 3 is a lower mold of the molding block in Example 1 of the present invention. (A) is a top view of a symbol by a plurality of processing marks, (b) is a cross-sectional view of a main part of the lower mold, (c) is an enlarged cross-sectional view of a main part of the lower mold, and FIG. It is a schematic sectional drawing of the shaping | molding apparatus in Example 1 of this invention.

  Reference numeral 1 denotes a molded part (optical element in the first embodiment), 2 denotes an optical surface of the optical element 1, and 3 denotes an outer shape formed integrally around the optical surface 2. Reference numeral 4 denotes a mark (marking portion) formed on the flat surface 3a of the outer shape portion 3 and made up of characters and symbols such as numerals, kanji and alphabets. The marking part 4 of “M105” shown here is set in advance so as to have information such as the manufacturing mold and date of manufacture of the optical element 1, and this marking part 4 is optical as will be described later. A plurality of machining marks arranged in advance so as to represent characters and symbols by electric discharge machining are added to a mold for molding the element 1 by being transferred in advance.

  The characters and symbols constituting the marking portion 4 are transferred from a plurality of concave processing marks arranged to represent the characters or symbols on the surface of the mold by electric discharge machining. Therefore, one of the marking portions 4 is transferred. One letter or symbol is a plurality of transfer elements having a height dimension h and an outer diameter c projecting from the flat surface 3a of the outer portion 3 of the optical element 1 in a substantially semicircular shape, for example, as shown in FIG. It is composed of five.

  FIG. 2A is a schematic cross-sectional view of a mold block 6 for molding the optical element 1, and a glass material 10 is inserted between an upper mold 8 and a lower mold 9 that are fitted to the upper and lower sides of the body mold 7. The glass material 10 is molded by being heated and pressed by the upper mold 8 and the lower mold 9. As shown in FIG. 2B, the flat portion 9a of the lower mold 9, that is, the surface forming the flat surface 3a of the outer portion 2 of the optical element 1 is subjected to electric discharge machining as described above. A plurality of concave processing marks 11 arranged so as to represent are formed, and the plurality of processing marks 11 are transferred to the optical element 1. In addition, you may provide this process trace 11 in the upper mold | type 8 side as needed.

  FIG. 3A shows one of symbols formed by a plurality of machining marks 11 on the flat portion 9a of the lower mold 9, and FIG. 3B shows a portion of the lower mold 9 where the machining marks 11 are located. FIG. 3C is an enlarged cross-sectional view of the main part of the lower mold.

  The marking portion 4 is added at a position indicating the direction of astigmatism generated in the optical element 1 according to various conditions such as accuracy of the molding die for molding the optical element 1, pressing conditions, or heating temperature. . When the optical element 1 having this astigmatism is composed of, for example, an objective lens of an optical pickup, when the objective lens is incorporated, the assembling position is set in advance in order to suppress the influence on the optical characteristics due to astigmatism. For example, in the case of the marking portion “M105” in the first embodiment, the center position of the entire character string may be set as a position indicating the direction of astigmatism. it can.

  The marking for the alignment is not limited to indicating the direction of astigmatism but may also be used as a mark indicating the direction of other aberrations such as coma.

  Here, when a processing mark is formed on a molding die, and this marking 11 is transferred to a molded part and a marking is added, the marking added to the molded part after molding is visually recognized by the surface roughness of the processing mark. Sex changes. Usually, the surface roughness of the flat surface 3a of the optical element 1 to which the marking portion 4 is added is a mirror surface of about Ry 100 nm due to the surface roughness of the flat portion 9a of the lower mold 9.

  Visibility of the marking part 4 partially added to the optical element 1 (surface roughness Ry 100 nm of the flat surface 3a) formed as described above and electric discharge machining into a mold (lower mold 9) made of super hard metal When the relationship with the surface roughness of the processing mark 11 (surface roughness of each transfer element 5) was examined, the evaluation results shown in Table 1 were obtained.

  From Table 1 above, it was found that the surface roughness Ry of the processing trace of the mold is Ry = 100 nm or more, preferably 300 nm or more, in order to ensure the visibility of the marking portion 4. That is, the surface roughness of each transfer element 5 constituting the marking portion 4 is not less than the surface roughness of the flat surface 3a of the optical element 1, and desirably not less than three times the surface roughness of the flat surface 3a.

  In addition, when the surface roughness of the processing trace of the mold is too large, particularly when the molded part is an optical element, since the antireflection film is generally formed on the surface, the adhesion of the marking portion film is deteriorated, Peeling may occur.

  In addition to improving the light transmittance of the optical element, the antireflection film has the effects of preventing scratches and preventing the generation of static electricity. A multilayer film is formed using a plurality of materials such as tantalum, zirconium, and yttrium. The film thickness of this film formation is about 1000 to several 1000 mm. Since this film formation is performed on the outer shape of the optical element so as to be surely attached to the optically effective surface of the optical element, the film is also formed on the marking unit 2.

  Table 2 shows the surface roughness of the transfer element 5 constituting the marking part 4 of the optical element, and after forming an antireflection film on the molded optical element, after 300 hours at 60 ° C. under high temperature and high humidity of 95% The result of having verified the relationship with the adhesiveness which did the film | membrane peeling test is shown.

  From Table 2 above, when the surface roughness of the transfer element 5 exceeds 5000 nm, the adhesion of the antireflection film is deteriorated. Therefore, the surface roughness of each transfer element 5 is desirably 5000 nm or less. From the above evaluation results, it was found that the surface roughness Ry of the marking portion should be rougher than the surface roughness of the molding surface to which the marking portion is added and the surface roughness should be 5000 nm or less. The adhesion varies slightly depending on the material of the antireflection film and the film formation conditions. The relationship between the surface roughness of the transfer element constituting the marking portion and the adhesion of the antireflection film is the result shown in Table 2 above. And no different.

  Next, when machining marks are made on the mold by electric discharge machining, depending on the distance from the edge of the machining surface of the electric discharge machining part, abnormalities such as shape defects in the machining marks and chipping on the machining surface may occur due to electric discharge abnormalities, etc. It turns out that there is a possibility. As shown in FIG. 3 (b), Table 3 shows the results of investigation on the distance Y1 (Y2) from the end of the flat portion 9a (processed surface) of the lower mold 9 to the process mark 11 (end of the process mark). .

  From the results shown in Table 3 above, the distance Y1 (Y2) from the end of the processed surface to each processed mark is preferably at least 20 μm or more, preferably 30 μm or more.

  Next, with respect to the dimensions of the machining marks 11 attached to the lower die 9 by electric discharge, the outer diameter of the machining marks 11 is described as C and the depth is H as shown in FIG. Is too large, the position of the center of gravity of the optical element 1 changes due to the weight of the plurality of transfer elements 5 formed by that portion. There is a risk that accurate optical characteristics cannot be obtained. In addition, the mold releasability during molding may be deteriorated, resulting in poor shape as marking. On the other hand, when the dimension of the machining mark 11 is small, the machining becomes difficult due to the limit value due to the electrode dimension of the electric discharge machining, and the visibility is deteriorated. Therefore, it is necessary to consider this minimum dimension.

  As for the relationship between the outer diameter C and the depth H of the processing mark 11, when the depth H is larger than the outer diameter C, the material is difficult to enter during molding and a defective shape occurs in the transfer element 5. There is a possibility that the shape accuracy of the marking portion is deteriorated.

  Table 4 shows the results of various verifications based on the above. In this table, ◯ is good, Δ is slightly bad, and x is bad. As can be seen from this, if the depth H is equal to or less than the outer diameter C with respect to the outer diameter C of the machining mark 11, molding is performed. Sometimes, the shape of the processing mark 11 of the mold is transferred to the optical element 1 satisfactorily. In this verification, the outer diameter C of the machining mark 11 was difficult to be 10 μm or less due to the limitation of the dimension of the electric discharge machining electrode. It is presumed that transfer is performed well under good processing as well. Therefore, it was found that if the relationship of “depth H of machining trace / outer diameter C of machining trace C ≦ 1” is satisfied, the moldability is good.

  Further, the depth dimension H of the processing mark 11 is convex in the molded part to which the processing mark 11 is transferred. Therefore, if the height dimension h is too large, a problem occurs during the assembly process. In the optical element 1 of the first embodiment, as a result of preliminary studies, if the height dimension h of each transfer element 5 of the marking unit 4 is 0.05 mm or less, this type of optical element, for example, a lens is assembled as a pickup device. It has been found that positioning during the process and fixing by bonding or the like do not hinder the performance as an optical component. If the height dimension h of each transfer element 5 is 0.05 mm or more, the height of the transfer element 5 may be affected by positioning during the assembly process or when fixed by bonding or the like, and the entire optical element 1 may be affected. There is a possibility that the volume of the marking portion 4 occupying increases and the center of gravity of the optical element shifts, affecting the optical performance. Therefore, it is desirable that the depth H of the processing mark of the mold is 0.05 mm or less.

  In addition to the size of each transfer element 5, if the number of transfer elements 5, that is, the number of markings 4, the number of symbols, etc., is increased, the performance of the optical element 1 may increase due to weight increase or center of gravity deviation. These may need to be taken into account as they can be problematic.

  In the above description, the height dimension h of the transfer element 5 and the depth dimension H of the processing mark 11 are substantially equal, and the outer diameter c of the transfer element 5 and the outer diameter C of the processing mark 11 are substantially equal. .

  The marking portion 4 is positioned on the flat surface 3a of the outer portion 3 on the receiving surface side of the optical element 1 or on the side opposite to the fixing surface or the adhesive surface in the assembly process of the optical element 1 to the pickup device or the like. If added, there is no visual inconvenience at the time of assembly. Therefore, not only can the marking indicate the direction of astigmatism, but it can also be used for subsequent failure analysis even when incorporated in a pickup device or the like. At this time, it is possible to easily discriminate between the optical elements molded by the same molding die or visually inspecting the marking portion at the time of history investigation such as production time.

  Next, a molding example of the optical element 1 will be described with reference to FIG. FIG. 4 is a schematic configuration diagram of a molding apparatus that continuously molds the optical element 1. A processing mark for marking is applied to the lower mold of each mold block 6, and a glass material is placed inside. Sequentially moved from left to right in FIG.

  More specifically, the molding block 6 for molding the optical element 1 from a glass material is conveyed by a robot (not shown) to the charging stage 41 of the molding apparatus 40, where the glass material 10 is charged. The mold block 6 is conveyed from the door (not shown) of the chamber chamber 42 to the preheating stage 43a, and the door is closed. The door is kept closed until the next molding block is carried in.

  The mold block 6 is a door (not shown) after being heated and pressurized by each press head 44 and cooled at each press stage of the preheating stage 43a, the molding stage 43b, the first cooling stage 43c, and the second cooling stage 43d. ) To the take-out stage 45, where it is disassembled by the robot and the optical element 1 is taken out. The conveyance in the molding apparatus 40 is performed by a conveyance arm.

  Here, the molding of the optical element 1 will be described in detail. As the glass material 10 constituting the optical element 1, VC79 (Tg = 507 ° C., At = 553 ° C.) manufactured by Sumita Optical Glass Co., Ltd. is used. Preliminarily processed into a substantially ball shape in advance, and then finished to a desired dimension by polishing.

  The upper mold 8 and the lower mold 9 of the mold block 6 are formed by processing a hard metal material into a desired shape, and the body mold 7 is made of stainless steel. The optical element 1 has an outer diameter of 3 mm and a center thickness of 1 mm. A plurality of machining marks 11 are arranged on the flat portion 9a of the lower mold 9 by electric discharge machining so as to represent numbers and symbols.

  One size of the processing mark 11 was an outer diameter C = Φ20 μm and a depth H = 10 μm. Further, it is known that the roughness of the electric discharge machining surface of the optical element 1 substantially matches the surface roughness of the electric discharge machining electrode, so that the surface roughness of the machining mark 11 is Ry = 1000 nm. The surface roughness was set to Ry = 1000 nm. And the distance from the edge of the flat part 9a (processed surface) of the lower mold | type 9 and each process trace 11 (end of process trace) ensured 0.05 mm or more all.

  The press stages 43a to 43d and the press heads 44 of the molding apparatus 40 shown in FIG. 4 each have a built-in heater so that the temperature can be set freely. Each press stage is heated in advance to a desired temperature, and after a predetermined time has passed, the mold block 6 is conveyed to the next press stage. In Example 1, the molding was performed at 50 sec tact.

  Table 5 shows the set temperatures for each press stage.

  In the molding apparatus 40, after the molding die block 6 is conveyed to the preheating stage 43a, the press head 44 is brought into contact with the upper die 8 and the glass material 10 is heated to a deformable temperature.

  Then, after a predetermined time has elapsed, the mold block 6 is transported to the next molding stage 43b by the transport arm. In this molding stage 43b, as in the preheating stage 43a, the press head is brought into contact with the upper mold and heated, and the optical element is molded with a pressing force of about 29.4 N (3 kgf) or less. At this time, the ball-shaped glass material 10 is deformed by the optical molding surfaces of the upper mold 8 and the lower mold 9.

  Next, the molding die block 6 is conveyed to the first cooling stage 43c, and the press head 44 is lowered and brought into contact with the upper die 8 in the same manner as the preheating stage 43a, and is pressurized with a pressure of about 980 N (about 100 kgf). The first cooling stage 43c is set to a temperature at which the molded optical element becomes lower than the deflection temperature under load at the end of the tact time.

  Then, the mold block 6 is transported to the second cooling stage 43d, and the press head 44 is brought into contact with the upper mold for cooling as in the first cooling stage 43c. The applied pressure at this time is the same applied pressure as that of the first cooling stage 43c. Then, after cooling the optical element to a temperature that can be taken out by the robot, the shaping block 6 is taken out of the shaping apparatus 40 and conveyed to the stage 45. Thereafter, the molding block 6 is transferred to a disassembly / assembly stage (not shown) by a robot and disassembled, and the optical element 1 is taken out.

  The surface roughness Ry of the marking portion 4 added to the flat surface 3a of the outer shape portion 3 of the optical element 1 molded as described above was 900 nm. And the visibility of the marking part 4 was also favorable, there was no peeling of an antireflection film, and the optical element performance was also favorable.

(Example 2)
FIGS. 5A and 5B show a part of the marking portion 50 added to the optical element in the second embodiment of the present invention, and a processing mark 52 applied to the molding die 51 for transferring it. It is the figure which showed the shape, and each transcription | transfer element which comprises the marking part 50 was made into elliptical shape, and the shape of the process mark 52 was also made elliptical.

(Example 3)
FIGS. 6A and 6B show a part of the marking portion 60 added to the optical element according to the third embodiment of the present invention, and a processing mark 62 applied to the molding die 61 for transferring it. It is a diagram showing the shape, each transfer element constituting the marking portion 60 is a square shape, and the shape of the processing mark 62 is also a square concave shape, and the same applies to the shapes of these embodiments. In addition, the above-described shape may be configured in a polygonal shape such as a cone, an elliptical cone, a triangular pyramid, a quadrangular pyramid, or other shapes.

  In each of the above embodiments, an optical element for molding a glass material has been described. However, the same applies to an optical element manufactured by injecting a resin material into a mold, except for the optical functional surface of an injection mold. By arranging a plurality of processing marks so as to form symbols or numbers by electrical discharge machining at the location, a marking portion having information can be added to the optical element to be injection molded.

  In the case of an optical element manufactured by the above injection molding, for example, since the gate portion which is a resin inflow passage into the mold at the time of lens molding is molded integrally with the lens, the gate portion from the lens body after these molding Cutting is done.

  However, as shown in FIG. 7, the trace 3b obtained by cutting the gate portion remains on the outer periphery of the lens main body, and the trace protrudes from the outer peripheral portion of the lens main body, that is, the outer peripheral surface of the outer shape, usually by 0.1 to 0.3 mm. Remain in. In order to absorb the trace on the bobbin for fixing the lens having such a trace, a concave portion is provided on the inner surface of the fitting portion of the lens body, and the protruding trace is inserted into the concave portion during assembly. At this time, a mark (marking) is provided on the upper surface of the outer portion in the vicinity of the gate portion in order to align the trace with the concave portion. The present invention is extremely useful because it can provide information such as the history of the lens in addition to the marking for such alignment.

  In each of the above descriptions, the marking portion is added to the outer portion of the optical element. However, this may be applied to the peripheral portion of the optical surface of the optical element, that is, the portion having no optical function in the optical surface. Good.

  In the above description, an optical element, particularly a lens, has been described as an example of a molded part. However, the same applies to other molded parts molded from a glass material or a resin material by a molding die.

  The present invention is extremely useful as a method for adding information such as the history of a molded part and a marking part indicating the mounting direction to a molded part such as an optical element molded from a glass material or a resin material by a molding die. It can be applied to various molded parts.

The optical element in Example 1 of this invention is shown, (a) is a side view, (b) is a bottom view, (c) is a top view of a marking part, (d) is sectional drawing of a marking part. The shaping | molding die block in Example 1 of this invention is shown, (a) is a schematic sectional drawing, (b) is a perspective view of a lower mold | type. FIG. 2 shows a lower die processing portion of the mold block in Example 1 of the present invention, (a) is a top view of a symbol by a plurality of processing marks, (b) is a cross-sectional view of a main part of the lower die, and (c) is a lower portion. Expanded sectional view of main part of mold Schematic block diagram of the molding apparatus in Example 1 of the present invention (A), (b) is the top view of the marking part added to the optical element in Example 2 of this invention, and sectional drawing which shows the process trace of a lower mold | type (A), (b) is the top view of the marking part added to the optical element in Example 3 of this invention, and sectional drawing which shows the processing trace of a lower mold | type The top view of the optical element in Example 4 of this invention

Explanation of symbols

1 Optical elements (molded parts)
2 Optical surface 3 External part 3a Flat surface 3b Trace 4 Marking part (mark)
DESCRIPTION OF SYMBOLS 5 Transfer element 6 Mold block 8 Upper mold 9 Lower mold 9a Flat part 10 Glass material 11 Processing trace 40 Molding apparatus

Claims (8)

A molding die for molding a molded part from a glass material or a resin material, and a plurality of processes having a surface roughness of 5000 nm or less, which is rougher than the surface roughness of the molding transfer surface, on the molding transfer surface of the molding die A molding die characterized by providing traces and arranging the plurality of machining traces so as to represent symbols or characters. 2. The molding die according to claim 1, wherein the machining trace is formed into a substantially circular, elliptical or polygonal concave shape by electric discharge machining. The size of machining marks by electric discharge machining is
Depth of machining mark / Outer diameter of machining mark ≦ 1
The molding die according to claim 2, wherein The molding die according to any one of claims 1 to 3, wherein an interval of at least 20 µm or more is provided between an end of a processing surface for forming a processing trace of the mold and an end of the processing trace. Type. A molded part formed by the molding die according to any one of claims 1 to 4, wherein a marking portion such as a symbol or a character is transferred and added by a processing mark. 6. The molded part according to claim 5, wherein the molded part is made of a lens, and the marking portion also serves as a marking for indicating the direction of aberration of the lens. 6. The molded part is made of a resin lens, and the marking portion also serves as a marking indicating a position of a cutting trace of the gate portion formed by an inflow passage of the resin material when the lens is molded. Molded parts. The molded part according to any one of claims 5 to 7, wherein the height of the marking portion transferred and added by the processing mark is 0.05 mm or less.

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