JP2003119038A - Lens, method of manufacturing lens, and optical pickup device - Google Patents

Abstract

(57) [Summary] [Problem] To reduce the adhesive force between an upper mold and a lens when manufacturing a glass lens by press molding, and to attach the lens to the upper mold when the mold is opened. To improve productivity and reduce costs. When a lens 1 is manufactured, a portion for transferring a shape to a surface of a flange 2 facing the same direction as an optical surface of a transfer surface 14a of a first molding die 14 is used as a second molding die 17.
The surface roughness of the surface of the flange is larger than that of the surface of the flange facing the same direction as the optical surface of the transfer surface 17a, and the lens formed by the transfer shape of the mold is in the same direction as the optical surface of the flange. Out of the two surfaces facing each other, the surface roughness is different between one surface and the other surface, so that the first mold has better mold release than the second mold, When the mold was opened, the lens was always held on the second mold side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup optical system for forming a light beam incident from an object on an image plane, a laser optical system for condensing a laser light beam emitted from a light source on a recording surface of a recording medium, and the like. TECHNICAL FIELD The present invention relates to a technique for improving the productivity of a lens made of glass used in.

[0002]

2. Description of the Related Art Glass used for an image pickup optical system for forming a light beam incident from an object on an image plane or a laser optical system for condensing a laser light beam emitted from a light source on a recording surface of a recording medium. The lens is generally manufactured by transferring the shape of the transfer surface of the mold by press molding.

FIG. 11 shows a conventional glass lens press molding process using a press molding machine a in order from (a) to (d).

In the press molding machine a, a first molding die (upper insert) e is attached to a vertically moving press cylinder b through a joint c and an upper die d, and a joint f and a lower die are mounted on a base (not shown). The second molding die (lower insert) h is attached via g.

In the press molding machine a, the glass material j conveyed by the conveying means i is placed on the second molding die h on the lower side, and when the glass material j is heated and softened, As shown in FIG. 11A, by moving the press cylinder b downward, the first molding die e and the second molding die e
When the glass material j is sandwiched between the glass material j and the molding die h, the shapes of the transfer surfaces of the first molding die e and the second molding die h are transferred to the glass material j and molded into a predetermined shape, The lens k is formed. After that, the lens k is transported by the transport means i.

The lens k has optical surfaces 1 and m formed on the front and back surfaces, and a flange n for attachment to a holding member such as a lens barrel is integrally formed on the outer peripheral edges of the optical surfaces 1 and m. ing.

[0007]

By the way, at the time of manufacturing the lens k using the press molding machine a, the lens k does not stay on the lower second molding die h but the upper second molding die h when the mold is opened. There is a problem in that the phenomenon that the molding die e of No. 1 remains in close contact frequently occurs. FIG. 11B
If the lens k remains attached to the upper first molding die e as shown in FIG. 11, not only the lens k cannot be automatically conveyed by the conveying means i, but also as shown in FIG.
When the adhesive force with the first molding die e becomes weaker with time and suddenly comes off from the first molding die e, and in extreme cases, it falls to the outside of the press molding machine a as shown in FIG. 11 (d). hand,
It was sometimes damaged. Further, even if the lens k that has come off the first molding die e falls on the second molding die h, the position will be displaced compared to the case where the lens k stays in the second molding die h from the beginning. However, even in this case, the automatic transfer by the transfer means i cannot be performed.

[0008] The above-mentioned problem is caused, in particular, as shown in FIG.
This often occurs when so-called free-edge molding is adopted in which the outer peripheral shape of the lens (outer peripheral shape of the flange) is not defined by a molding die. That is, the lens o formed by the free-edge molding has the same shape as the second outer surface of the flange p during molding.
Since there is no friction with the molding die h of the second molding die h of FIG.
This is because it is easy to remain attached to the upper first molding die e instead of staying on the upper side.

Even if the above-mentioned free edge molding is not adopted, if the shape of the outer peripheral surface of the flange is regulated, friction between the lower die g and the flange is reduced, and the flange having a small thickness in the optical axis direction (thickness Is less than or equal to 1 mm) or the radius of curvature of the optical surface transferred by the first mold e is much larger than the radius of curvature of the optical surface transferred by the second mold h. , When the mold is opened, the lens does not remain on the lower second molding die h,
It tends to remain attached to the upper first molding die e.

If the lens cannot be automatically conveyed, the lens must be conveyed manually, and personnel must be arranged on the side of the press molding machine, which makes it impossible to automate the production of the lens.

Therefore, due to the above problems, in the conventional production of glass lenses by press molding, productivity cannot be improved, yield is deteriorated, and personnel must be allocated due to failure of automatic transfer by the transfer means or damage. There was an unavoidable increase in costs due to the necessity.

In view of the above-mentioned problems, the present invention reduces the adhesive force between the upper mold and the lens when manufacturing a glass lens by press molding, so that the upper mold has a lens when the mold is opened. It is an object of the present invention to improve productivity and reduce cost by eliminating the adherence of ash.

[0013]

In order to solve the above problems, the present invention provides a first transfer pattern including an optical surface.
And a second molding die, a glass material is placed between the second molding die and the glass material, the glass material is heated to a predetermined temperature to be softened, and then the two molding dies are pressed to transfer the transfer shape. A method for manufacturing a lens integrally having a flange for attachment to a holding member on an outer peripheral edge of an optical surface,
The part that transfers the shape to the surface of the flange that faces the same direction as the optical surface of the transfer surface of the mold is transferred to the surface of the flange that faces the same direction as the optical surface of the transfer surface of the second mold. The surface of the lens formed by the transfer shape of the molding die is made rougher than that of the surface of the flange, and the surface of one of the two surfaces facing the same direction as the optical surface of the flange is rough. The first mold has better mold release than the second mold because there is a difference in the degree, and the lens is always held on the second mold side when the mold is opened. It is the one.

Therefore, when the mold is opened, the lens is prevented from adhering to the upper molding die, and one of the two surfaces facing the same direction as the optical surface of the flange is roughened and the other is rough. It is possible to provide lenses with different degrees.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the lens, the lens manufacturing method and the optical pickup device of the present invention will be described below with reference to the accompanying drawings.

First, the lens of the present invention will be described.

The lens 1 of the present invention is manufactured by a manufacturing method described later, and as shown in FIGS. 1 to 3, a flange 2 for attachment to a holding member is provided on the outer peripheral edge of the optical surfaces S1 and S2. It is made of glass and is used as an optical element of an imaging optical system that is integrally formed and forms a light flux from an object on the image plane, or an optical element of a laser optical system that focuses a laser light flux emitted from a light source on the recording surface of a recording medium. It is a lens.

Ring-shaped flat surfaces (hereinafter referred to as "ring surfaces") 2a and 2b of the flange 2 of the lens 1 facing the same sides as the optical surfaces S1 and S2, respectively, have surface roughnesses. In the comparison by the Ra (center line average roughness) value representing the surface roughness, there is a difference of at least 3 times or more.

Specifically, as shown in FIGS. 1 and 3,
By devising the shape of the transfer surface of the corresponding part of the mold at the manufacturing stage by press molding (details will be described later),
The surface roughness of the ring surface 2b on the optical surface S2 side is made rough. That is, the ring surface 2b is the optical surface S
Compared to the ring surface 2a on the side of 1 and other portions, the surface is rough so that the difference can be visually confirmed. The surface shape of the ring surface 2b is exaggeratedly shown in the partially enlarged view in FIG. 1, but is not in the shape of a sawtooth, and is in a so-called textured state. Has become.

Therefore, the lens 1 is used as an optical element of an imaging lens system or a laser optical system because the ring surface 2b of the flange 2 has a surface roughness higher than that of other portions. Sometimes, stray light generated from the flange 2 can be eliminated, and at the time of assembly, the difference in surface roughness of this surface is caused by the fact that only the ring surface 2b of the flange 2 has a rough surface. It can also be used to confirm the orientation of the lens 1 (determine the front and back sides that have been specified in advance).

Next, a method of manufacturing the lens 1 will be described. The lens 1 is manufactured by a so-called glass press molding method, which is a method of obtaining a lens by heating a glass material to a predetermined temperature to soften it, and transferring a transfer surface shape of a molding die (insert) processed into an optical mirror surface. To be done.

FIG. 4 shows the steps of press molding the lens 1 using the press molding machine 10 based on the lens manufacturing method of the present invention.

In the press molding machine 10, a first molding die (upper insert) 14 is attached to a vertically moving press cylinder 11 via a joint 12 and an upper die 13, and a joint 15 and a lower die are attached to a base (not shown). A second molding die (lower insert) 17 is attached via 16.

In the press molding machine 10, as shown in FIG. 4A, the glass material 19 conveyed by an appropriate conveying means 18 is placed on the lower insert 17 on the lower side, and the glass material 19 is placed. When the is heated and softened, as shown in FIG. 4B, when the press die 11 is moved downward to press the upper die 13 to the lower die 16, the upper insert 14, the lower insert 17, and A space having the outer shape of the lens 1 is formed by the lower die 16, and the glass material 19 is molded into a predetermined shape between these to form the lens 1.

Then, after cooling the molded lens 1, as shown in FIG. 4 (c), the press cylinder 11
The upper insert 14 and the lower insert 1 by moving the
When the mold is opened by separating the lens 7 from the lens 7, the lens 1 remains held on the lower insert 17. Finally, as shown in FIG. 4D, the lens 1 on the lower insert is conveyed by the conveying means 18. In addition, press molding machine 1
The outer peripheral surface of the flange 2 of the lens 1, which is molded by 0, as shown in FIG. 4 (b), is the inner peripheral surface 1 of the lower die 16 protruding above the transfer surface 17 a of the lower insert 17.
The shape is defined by 6a.

The upper insert 14 and the lower insert 1
Reference numeral 7 denotes a surface for transferring a predetermined lens shape to the glass material 19, which is formed by grinding a block-shaped member made of ceramics (SiC or the like) or cemented carbide.
The transfer surfaces 14a and 17a are formed. The transfer surfaces 14a and 17a are the optical surfaces S2 and S2 of the lens 1, respectively.
An optical surface transfer portion 14b which is a portion for forming S1;
17b, and flange transfer portions 14c and 17c which are portions for forming the flange 2. In the flange transfer portions 14c and 17c, the surface of one flange transfer portion 14c has a rougher surface than the surface of the other flange transfer portion 17c.

The transfer surface 1 of the upper insert 14 and the lower insert 17 is secured in order to ensure the mold release with the glass.
CVD (Chemical Vapor Depositio) is provided on 4a and 17a.
n: Chemical vapor deposition) method or PVD (Physical Vapor)
Deposition: a film of DLC (Diamond Like Carbon), which is a kind of carbon material, formed by physical vapor deposition, platinum (Pt), iridium (Ir), etc. formed by a sputtering method. In addition, the upper die 13 and the lower die 16
Is made of cemented carbide. Both the above ceramics and cemented carbide are brittle materials that can withstand high temperatures.

The lens 1 molded as described above is
In particular, in the case of being used as an optical element of an image pickup lens system, in order to prevent flare, the optical surfaces S1 and S
The surface roughness of the surface of No. 2 is required to be extremely good.
Therefore, the upper insert 1 used in the press molding machine 10
4 and the transfer surfaces 14a and 17a of the lower insert 17, especially the optical surface transfer portions 14b and 17b for forming the optical surfaces S2 and S1 of the lens 1 can be subjected to not only grinding processing but also polishing processing. is necessary. Optical surface transfer portions 14b and 17 of the upper insert 14 and the lower insert 17
By performing the polishing process on b, the grinding marks (opening) are eliminated, so that the lens 1 formed by using the upper insert 14 and the lower insert 17 does not transfer the opening, and thus the It becomes possible to suppress the scattering.

In general, when materials having a good surface roughness are brought into close contact with each other, air is not introduced into the close contact surfaces, which results in a vacuum state and the two stick to each other. The better the surface roughness of each other, the higher the degree of vacuum between them becomes, and the more likely they are to stick. This means that the press molding machine 1 shown in FIG.
In a lens manufacturing process using 0, the lens sticks to the upper insert 14 when the press cylinder 11 is moved upward to separate the upper insert 14 and the lower insert 17 and mold opening is performed. Also applies to

For example, when a lens is formed by using an insert having a transfer surface polished with fine abrasive grains, since the surface of the lens and the transfer surface of the insert have good surface roughness, the degree of adhesion between them is high. Will rise.
On the contrary, when the transfer surface of the insert is only ground, or when the transfer surface of the insert is polished with coarse abrasive grains, the surface roughness of the transfer surface of the insert and the surface of the lens become rough. The adhesion of is also poor.

Further, the larger the radius of curvature of the optical surface of the lens to be molded, the looser the connecting angle of the surface shape at the boundary between the optical surface transfer portion and the flange transfer portion of the insert transfer surface, and the insert transfer surface. Since the shape of is close to flat, during press working as shown in FIG.
The flow of softened glass in the upper and lower inserts is improved, and it becomes easier to fill the outer peripheral parts of the upper and lower inserts with glass, increasing the contact area between the transfer surface and the lens surface, and the adhesion between the two Will rise. On the contrary, as the radius of curvature of the optical surface of the lens to be molded is smaller and the depth of the surface is deeper, the shape of the transfer surface of the insert has a deeper concave surface, so the softened glass flow in the upper and lower inserts. Is deteriorated, and it becomes difficult to fill the outer peripheral portion of the mold with the glass, and the contact area between the transfer surface and the lens surface is reduced, so that the adhesiveness between the two is lowered.

When molding glass with a high filling rate to form a lens having a flange like the lens 1, it is important to center the optical surface transfer portion of the insert and the glass material.
Therefore, as shown in FIG. 4A, the spherical glass material 1
9 and the glass material 19 is attached to the lower insert 17 by its own weight.
In general, the optical surface transfer portion 17c is rolled to perform positioning (centering). In the press molding machine 10, the optical surface transfer portion 17c of the lower insert 17 is
In order to facilitate the positioning between the glass material 18 and the glass material 18 and the maintenance of the position after positioning, the insert having the smaller radius of curvature of the optical surface forming surface of the transfer surface and the deeper surface is the lower insert 1.
7, the insert having a large radius of curvature of the optical surface forming surface of the transfer surface and a shallow surface depth is used as the upper insert 14. As a result, the upper insert 14 inevitably has a shape of the transfer surface 14a that is nearly flat. Therefore, as described above, the lens after molding has the transfer surface 14a of the upper insert 14 more than the transfer surface 17a of the lower insert 17. The adhesion to the transfer surface 14a becomes large, and the phenomenon that the upper insert 14 remains stuck to the transfer surface 14a when the mold is opened easily occurs.

Therefore, as shown in FIGS. 5 and 7, the upper insert 14 used in the press molding machine 10 using the lens manufacturing method of the present invention has only the surface of the flange transfer portion 14c of the transfer surface 14a as appropriate. The surface is roughened by the rough surface forming means. Specifically, at the time of polishing after the transfer surface 14a of the upper insert 14 has been ground, the optical surface transfer portion 14b is polished with a coarser abrasive grain than the abrasive grain, and the surface roughness of the surface of the flange transfer portion 14c is increased. Is a large one. The surface of the flange transfer portion 17c of the lower insert 17 is polished with finer abrasive grains than the abrasive grains for polishing the flange transfer portion 14c, as shown in FIG. The abrasive grains for polishing the surface of the flange transfer portion 17c of the lower insert 17 may be the same as the abrasive grains for polishing the optical surface forming portions 14b, 17b of the upper insert 14 and the lower insert 17.

Then, in the lens 1 molded by the press molding machine 10, as described above, the surface roughness of the ring surfaces 2a and 2b of the flange 2 represents the surface roughness R described above.
In order to make a difference of at least 3 times or more in the comparison by the a value, the ring surface 2b having the larger surface roughness is used.
The surface roughness of the surface of the flange transfer portion 14c of the upper insert 14, which is the surface on which the transfer is performed, is at least 5 times or more different in Ra value compared to the surface roughness of the surface of the flange transfer portion 17c of the lower flange 17. Is being done.

The lens 1 is formed by the press molding machine 10 having the structure described above. Therefore, the optical surface S in which the radius of curvature of the flange 2 of the lens 1 is large
The ring surface 2b on the second side is in a state where the surface is textured.

FIG. 8 shows the lens manufacturing method of the present invention applied to a press molding machine 10A for performing free edge molding.

As shown in FIG. 8, the press molding machine 10A is slightly different from the press molding machine 10 in the shapes of the upper die 13, the upper insert 14, the lower die 16 and the lower insert 17. That is, the upper insert 14 and the lower insert 17 used in the press molding machine 10A have larger outer diameters than those used in the press molding machine 10, and the upper die 13 and the lower die 16 are used in the press molding machine 10A.
By making the inner diameter larger than that used in the above, it is possible to prevent the glass material 19 that is pressed and deformed from contacting the inner peripheral surface 16a of the lower die 16 during the press forming shown in FIG. 8 (a). is there. Therefore, the press molding machine 1
The same reference numerals as those used for each part of the press molding machine 10 are used for 0A, and detailed description thereof will be omitted.

By the way, in free-edge molding in which the glass softened by heating is not filled up to the side wall of the die, the centering of the optical surface forming portion of the insert and the glass material is not a problem, so the gob glass material (costly glass material) A glass material that is not a true sphere only for weight management) is often used. Although it is not necessary to center the optical surface forming portion of the insert and the glass material to the same extent as in the case of the press molding machine 10, it is better to place the glass material at the center of the optical surface forming portion of the insert to some extent. It is advantageous in terms of the surface accuracy of the lens and the fact that the machining allowance for the centering processing of the lens can be reduced.

Therefore, also in the above press molding machine 10A, the optical surface transfer portion 17b of the lower insert 17 and the glass material 19 are formed.
In order to make it easier to position and to maintain the position after positioning, the optical surface forming surface of the transfer surface has a smaller radius of curvature and the deeper surface is used as the lower insert 17 to form the optical surface of the transfer surface. An insert having a large radius of curvature of the surface and a shallow surface depth is used as the upper insert 14.

In the press molding machine 10A, since free edge molding is performed, interference between the inner peripheral surface 16a of the lower die 16 and the outer peripheral surface of the lens flange is eliminated regardless of the wall thickness of the lens to be molded. In many cases, the lens remains attached to the upper insert 14 when the mold is opened.
Therefore, in the press molding machine 10A as well, the upper insert 14 is used by using the upper insert 14 of the press molding machine 10.
The adhesion between the lens 4 and the lens 1A is reduced.

Finally, as an example of an apparatus using the lens of the present invention as an objective lens of an optical pickup apparatus, a disk-shaped recording medium (magneto-optical disk, optical disk, etc.) having a diameter of 64 mm is rotatable in a flat case. 1 shows a disk drive device which uses a disk cartridge housed therein and reproduces an information signal recorded on the disk-shaped recording medium and / or records an information signal on the disk-shaped recording medium.

As shown in FIG. 9, the disk drive device 30 comprises a thin box-shaped outer casing 31 in which required members and mechanisms are arranged.

A laterally long rectangular insertion / removal opening 31a is formed on the front surface of the outer casing 31, and a door 31b is provided on the outer casing 31 to close the insertion / removal opening 31a to prevent dust and the like from entering.

Inside the outer casing 31, as shown in FIG. 9, a chassis 32 is arranged. A drive motor (spindle motor) (not shown) is arranged on the lower surface side of the chassis 32 substantially at the center, and the rotation shaft of the drive motor penetrates through the chassis 32 and projects upward, and the disk table 33 is fixed to the rotation shaft. ing.

An arrangement hole 32a is formed in the chassis 32, and the disc table 33 is in a state of protruding above the upper surface of the chassis 32. A lead screw 34 and a guide shaft 35 are arranged in parallel with each other on the lower surface side of the chassis 32. Then, at a position corresponding to the arrangement hole 32a of the chassis 32, the optical pickup device 36 is mounted in the disc table 33 in the radial direction (radial direction) of the disc-shaped recording medium, that is,
It is movably supported in the direction indicated by arrow A in FIG.

In the optical pickup device 36, as shown in FIGS. 9 and 10, each member required for the moving base 37, that is, the objective lens driving mechanism (biaxial actuator).
38, a laser coupler (integrated optical element) 39, etc. are arranged.

The objective lens driving mechanism 38 has a support base (fixed portion) 40 and a movable portion 41 supported by the support base 40. The movable portion 41 has a lens holder portion 42 formed integrally therewith, and an objective lens 43 having a predetermined shape is held by a holding frame 44 with its outer edge portion pressed.

As shown in FIG. 10, the movable portion 41 is slidable in the axial direction of the support shaft 45 by being externally fitted to the support shaft 45 of the support base 40. It is supported rotatably around the axis.

By the way, the objective lens 43 is formed by the press molding machine 10, and although detailed illustration is omitted, it has a flange like the lens 1, and has the same side as the two optical surfaces. The annular ring surface of the facing flange has a surface roughness of at least three times or more as compared with the Ra value representing the surface roughness, and is likely to be textured. It has a surface shape.

As described above, according to the present invention, the flange transfer portion of the transfer surface of the upper insert of the press molding machine has a surface roughness higher than that of the flange transfer portion of the lower insert by an Ra value of at least 5 times or more. The lenses formed by the transfer surfaces of the upper insert and the lower insert are roughened so that there is a difference, and one of the two surfaces of the flange facing the same direction as the optical surface and the other surface Ra for surface roughness
There is at least a three-fold difference in the values, so that the upper insert makes better mold release than the lower insert, and the lens is always held at the predetermined position of the lower insert when the mold is opened. Therefore, when the mold is opened, the lens does not adhere to the upper insert, so that the lens can be automatically conveyed at the time of manufacturing, which makes it possible to achieve high productivity and reduce damage to the lens. The yield can also be improved.

Further, it is possible to provide a lens in which one of the two surfaces facing the same direction as the optical surface of the flange has a different surface roughness, and it is possible to discriminate between the front surface and the back surface of the lens. It becomes possible to easily perform the above, and it is also possible to reduce stray light by the surface having a rough surface roughness and a surface shape such as a textured surface.

Further, in the optical pickup device using the lens of the present invention as the objective lens, the surface roughness of the flange when the lens is attached is rough and the direction of one surface having the surface shape such as the texture is preliminarily set. By prescribing, when assembling the optical pickup device, it becomes easy to arrange the optical surfaces of the objective lens so as to be in the prescribed directions, and it is possible to improve the productivity of the optical pickup device. become. Also,
It is also possible to reduce stray light by using a surface having a rough surface and a textured surface shape.

It should be noted that the specific shapes and structures of the respective parts shown in the above-mentioned embodiments are merely examples of specific embodiments in carrying out the present invention, and the technical features of the present invention are thereby obtained. The scope should not be limitedly interpreted.

[0054]

As is apparent from the above description, the lens of the present invention is a glass lens in which a flange for attachment to a holding member is integrally formed on the outer peripheral edge of the optical surface. Among the two surfaces facing in the same direction, one surface and the other surface are different in surface roughness.

Therefore, of the two surfaces facing the same direction as the optical surface of the flange, there is a difference in surface roughness between the one surface and the other surface, so that it is possible to easily determine the front surface and the back surface of the lens. At the same time, the surface of the flange having a rough surface can reduce stray light.

In the invention described in claim 2, of the two surfaces facing the same direction as the optical surface of the flange, the surface roughness of one surface is three times as large as the surface roughness of the other surface. Since it is roughened as described above, it becomes possible to more easily discriminate between the front surface and the back surface of the lens, and it is possible to further reduce stray light.

In the invention described in claim 3, of the two surfaces facing in the same direction as the optical surface of the flange, the surface whose surface roughness is rougher than one is the two optical surfaces. Since the surface facing the same side as the optical surface having a large radius of curvature is formed, the releasability on the side of the optical surface having a large radius of curvature can be improved at the time of manufacturing the lens.

In the invention described in claim 4, the surface roughness of the two surfaces facing the same direction as the optical surface of the flange is:
Since the difference is made to the extent that the difference in the surface shape can be visually recognized, the front and back of the lens can be visually determined.

Further, in the lens manufacturing method of the present invention, the glass material is placed between the first and second molding dies on which the transfer shape including the optical surface is formed, and the glass material is heated to a predetermined temperature. After being softened by softening, the two molding dies are pressed together to transfer the transfer shape, and the lens having the flange for mounting to the holding member integrally on the outer peripheral edge of the optical surface is manufactured. In the method, a portion of the flange whose surface is oriented in the same direction as the optical surface of the transfer surface of the first mold is a portion of the flange which is oriented in the same direction as the optical surface of the transfer surface of the second mold. The surface roughness is made rougher than the part where the shape is transferred to the surface, and the lens molded by the transfer shape of the molding die faces the same direction as the optical surface of the flange.
Of the two surfaces, one surface and the other surface have a difference in surface roughness so that the first molding die is better than the second molding die, and when the mold is opened, It is characterized in that the lens is always held on the second molding die side.

Therefore, when the mold is opened, the lens does not adhere to the first mold, and the lens is always held at the predetermined position of the second mold, so that the lens is automatically conveyed at the time of manufacturing. Therefore, it is possible to always achieve high productivity, and at the same time, it is possible to reduce lens damage and improve yield.

In the invention described in claim 6, the first
Since the rough surface forming means roughens the surface of the portion that transfers the shape to the surface of the flange facing the same direction as the optical surface of the transfer surface of the molding die, the two surfaces of the flange facing the same direction as the optical surface. In addition, the surface roughness can be made different.

According to the seventh aspect of the invention, the surface of the second molding die is smoothed by polishing the portion for transferring the shape to the surface of the flange facing the same direction as the optical surface of the transfer surface. Therefore, the two surfaces of the flange facing the same direction as the optical surface can have different surface roughness.

In the invention described in claim 8, the portion for transferring the shape to the surface of the flange facing the same direction as the optical surface of the transfer surface of the first molding die has a relatively large abrasive grain. By polishing with a relatively small abrasive grain, the portion of the second mold that transfers the shape to the surface of the flange facing the same direction as the optical surface of the transfer surface is polished. Since the respective surface roughnesses are different from each other, it is possible to make the two surface surfaces of the flange facing the same direction as the optical surface have a clear difference in surface roughness.

According to the ninth aspect of the invention, after the mold is opened, the lens held in the second molding die is conveyed by the conveying means, so that the lens production efficiency can be improved. it can.

Further, the optical pickup device of the present invention has an optical system including a laser light emitting element, a light receiving element and an objective lens, and the laser light emitted from the laser light emitting element by the objective lens is recorded on the recording surface of the disc-shaped recording medium. An optical pickup device, which is configured to perform recording and reproduction of a signal to and from the disc-shaped recording medium, or to perform only reproduction, wherein an objective lens is attached to a holding member on an outer peripheral edge of an optical surface. The flange of is integrally formed,
Of the two surfaces facing the same direction as the optical surface of the flange,
It is characterized in that there is a difference in surface roughness between one surface and the other surface.

Therefore, by predefining the orientation of the surface with rough surface roughness of the flange when the objective lens is mounted,
At the time of assembling the optical pickup device, it becomes easy to arrange the respective optical surfaces of the objective lens so as to be in a prescribed direction, so that the productivity of the optical pickup device can be improved and the surface roughness is rough. By face
Stray light can also be reduced.

[Brief description of drawings]

FIG. 1 shows, together with FIGS. 2 to 10, an embodiment of a lens, a lens manufacturing method, and an optical pickup device of the present invention. Is

FIG. 2 is a front view of a lens.

FIG. 3 is a rear view of the lens.

FIG. 4 shows steps (a) to (d) of the lens manufacturing method.
It is the schematic which shows in order.

FIG. 5 is an enlarged vertical sectional view of a first molding die.

FIG. 6 is an enlarged vertical sectional view of a second molding die.

FIG. 7 is an enlarged plan view showing a transfer surface of the first mold.

FIG. 8 is a schematic view showing a part of the manufacturing process in the free edge molding method in order from (a) to (b).

FIG. 9 is a perspective view schematically showing the structure of a disk drive device as an example of a device using an optical pickup device.

FIG. 10 is a perspective view schematically showing the structure of an optical pickup device.

FIG. 11 is a schematic view showing part of the steps in the conventional method for manufacturing a lens, in order from (a) to (d).

FIG. 12 is a schematic view showing a part of the manufacturing process in the conventional free edge molding method in order from (a) to (b).

[Explanation of symbols]

1 ... Lens, 2 ... Flange, 2a ... One surface, 2b ... Other surface, S1 ... Optical surface, S2 ... Optical surface, 14 ... First molding die, 14a ... Transfer surface, 17 ... Second molding die , 17a ...
Transfer surface, 36 ... Optical pickup device, 43 ... Objective lens

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[Procedure amendment]

[Submission date] November 28, 2001 (2001.11.
28)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

In the press molding machine a, a first molding die (upper insert) e is attached to a vertically moving press cylinder b through a joint c and an upper die (upper frame die) d, and is mounted on a base (not shown). A second molding die (lower insert) h is attached through a joint f and a lower die (lower frame die) g.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

[0013]

In order to solve the above-mentioned problems, the present invention provides a structure in which a transfer shape including an optical surface is supported between upper and lower frame dies, and a transfer shape is formed between the first and second molding dies. It is formed by placing a glass material on it, heating it to a predetermined temperature to soften it, then pressing the upper and lower frame dies into contact with each other to transfer the transfer shape, and attaching it to the holding member on the outer peripheral edge of the optical surface. In the method of manufacturing a lens integrally having a flange for use in molding, a portion for transferring the shape to the surface of the flange facing the same direction as the optical surface of the transfer surface of the first molding die is used as a portion of the transfer surface of the second molding die. The surface roughness is made rougher than the part that transfers the shape to the surface of the flange facing the same direction as the optical surface, and the lens formed by the transfer shape of the molding die has two surfaces facing the same direction as the optical surface of the flange. Among the surfaces, there is a difference in surface roughness between the one surface and the other surface. In this way, the first molding die is better than the second molding die in releasing, and the lens is always held on the second molding die side when the mold is opened. .

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

The press molding machine 10 includes a press cylinder 11 that moves up and down, a joint 12 and an upper frame die (hereinafter,
It is called "upper die". ) 13 through the first molding die (hereinafter
Lower, "upper insert". ) 14 is attached, a joint 15 and a lower frame type (hereinafter referred to as “lower die” ) to a base not shown.
Say. ) 16 through the second molding die (hereinafter referred to as “lower in
"Sart". ) 17 is attached.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

In the press molding machine 10, as shown in FIG. 4A, the glass material 19 conveyed by an appropriate conveying means 18 is placed on the lower insert 17 on the lower side, and the glass material 19 is placed. When the upper die 13 is heated and softened, as shown in FIG. 4 (b), the press die 11 is moved downward to press the upper die 13 to the lower die 16, so that the upper insert 14 and the lower insert 17 A space having the outer shape of the lens 1 is formed by the lower die 16 and the glass material 19 is formed into a predetermined shape between them to form the lens 1.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0059

[Correction method] Change

[Correction content]

Further, in the lens manufacturing method of the present invention, the glass material is placed between the first and second molding dies which are respectively supported by the upper and lower frame dies and on which the transfer shape including the optical surface is formed. after heated and softened a the nitric material to a predetermined temperature, the upper and lower
In the method for manufacturing a lens, which is formed by pressing the frame die of FIG. 1 and transferring the above-mentioned transfer shape, and integrally has a flange for attaching to the holding member on the outer peripheral edge of the optical surface, the transfer of the first molding die Surface of the surface that transfers the shape to the surface of the flange that faces the same direction as the optical surface of the second molding die, than the surface that transfers the shape to the surface of the flange that faces the same direction as the optical surface of the transfer surface of the second mold. The surface of the lens, which has a roughened surface and is molded by the transfer shape of the molding die, has a difference in surface roughness between one of the two surfaces facing the same direction as the optical surface of the flange. In this way, the first mold is better than the second mold in releasing the mold, and when the mold is opened, the second mold is always used.
The lens is held on the side of the mold.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 shows, together with FIGS. 2 to 10, an embodiment of a lens, a lens manufacturing method, and an optical pickup device of the present invention. Is

FIG. 2 is a front view of a lens.

FIG. 3 is a rear view of the lens.

FIG. 4 shows steps (a) to (d) of the lens manufacturing method.
It is the schematic which shows in order.

FIG. 5 is an enlarged vertical sectional view of a first molding die.

FIG. 6 is an enlarged vertical sectional view of a second molding die.

FIG. 7 is an enlarged plan view showing a transfer surface of the first mold.

FIG. 8 is a schematic view showing a part of the manufacturing process in the free edge molding method in order from (a) to (b).

FIG. 9 is a perspective view schematically showing the structure of a disk drive device as an example of a device using an optical pickup device.

FIG. 10 is a perspective view schematically showing the structure of an optical pickup device.

FIG. 11 is a schematic view showing part of the steps in the conventional method for manufacturing a lens, in order from (a) to (d).

FIG. 12 is a schematic view showing a part of the manufacturing process in the conventional free edge molding method in order from (a) to (b).

[Explanation of Codes] 1 ... Lens, 2 ... Flange, 2a ... One surface, 2b ... Other surface, S1 ... Optical surface, S2 ... Optical surface, 13 ... (top) frame
Mold, 14 ... First mold, 14a ... Transfer surface, 16 ...
(Bottom) Frame die, 17 ... Second molding die, 17a ... Transfer surface, 3
6 ... Optical pickup device, 43 ... Objective lens

Claims (10)

[Claims] 1. A lens made of glass, wherein a flange for attachment to a holding member is integrally formed on an outer peripheral edge of an optical surface, and the lens is one of two surfaces facing the same direction as the optical surface of the flange. A lens having a difference in surface roughness between one surface and the other surface. 2. The optical element facing the same direction as the optical surface of the flange.
The lens according to claim 1, wherein one of the two surfaces has a surface roughness three times or more higher than that of the other surface. 3. A flange facing the same direction as the optical surface of the flange.
The surface of which the surface roughness is rougher than one of the two surfaces is a surface facing the same side as the optical surface of the two optical surfaces having a large radius of curvature. The listed lens. 4. The optical fiber of the flange is oriented in the same direction as the optical surface of the flange.
2. The lens according to claim 1, wherein the surface roughness of the two surfaces is different to the extent that the difference in surface shape can be visually recognized. 5. A first transfer pattern including an optical surface is formed.
And a second molding die, a glass material is placed between the second molding die and the glass material, the glass material is heated to a predetermined temperature to be softened, and then the two molding dies are pressed to transfer the transfer shape. A method for manufacturing a lens integrally having a flange for attachment to a holding member on an outer peripheral edge of an optical surface, wherein the flange surface is oriented in the same direction as the optical surface of the transfer surface of the first mold. The transfer surface of the second mold is made rougher than that of the transfer surface of the flange, which is oriented in the same direction as the optical surface of the transfer surface of the second mold, and is molded by the transfer shape of the mold. Of the two surfaces of the lens facing the same direction as the optical surface of the flange, there is a difference in surface roughness between the one surface and the other surface, and the first mold is the second surface. The mold release is better than that of
A method for manufacturing a lens, wherein the lens is always held on the second molding die side when the mold is opened. 6. The rough surface forming means roughens the surface of the portion for transferring the shape to the surface of the flange facing the same direction as the optical surface of the transfer surface of the first molding die. A method for manufacturing the lens according to. 7. The surface of the second molding die is smoothed by polishing the portion for transferring the shape to the surface of the flange facing the same direction as the optical surface of the transfer surface. A method for manufacturing the described lens. 8. A portion for transferring the shape to the surface of the flange facing the same direction as the optical surface of the transfer surface of the first molding die is polished with relatively large abrasive grains, and at the same time, the second It seems that there is a difference in surface roughness by polishing the part that transfers the shape to the surface of the flange facing the same direction as the optical surface of the transfer surface of the mold by using relatively small abrasive grains. The lens manufacturing method according to claim 5, wherein 9. The method of manufacturing a lens according to claim 5, wherein after the mold is opened, the lens held by the second molding die is conveyed by a conveying means. 10. An optical system including a laser light emitting element, a light receiving element, and an objective lens, wherein the laser light emitted from the laser light emitting element by the objective lens is condensed on a recording surface of a disk-shaped recording medium, Is an optical pickup device for recording and / or reproducing a signal to / from a recording medium, wherein the objective lens is integrally formed with a flange for attachment to a holding member on an outer peripheral edge of an optical surface. The optical pickup device is characterized in that, of the two surfaces facing the same direction as the optical surface of the flange, one surface and the other surface have a difference in surface roughness.