JP6957133B2 - Glass molding lens, lens molding equipment and lens manufacturing method - Google Patents

Description

The present invention relates to a glass molding lens, a lens molding apparatus, and a lens manufacturing method.

Lenses for optical communication include, for example, a laser diode and one that is surface-mounted on a substrate on which an end portion of an optical fiber is mounted and collects light output from the laser diode on the end face of the optical fiber. It has been known.

As such a lens, a glass lens is generally used instead of a resin lens (see, for example, Patent Document 1).
Patent Document 1 uses a square lens having a square outer peripheral shape of the glass lens. For surface mounting on a substrate, it is preferable that the outer circumference of the lens has a flat surface (reference surface). That is, the lens can be stably arranged on the mounting surface of the substrate by mounting the lens on the mounting surface (flat surface on the substrate) of the substrate so that the outer peripheral plane of the lens is in contact with the mounting surface of the substrate. .. Also, if the arrangement relationship between the optical axis of the lens and the plane is determined and the plane is the reference plane, the distance of the optical axis from the substrate can be determined simply by bringing the reference plane into contact with the mounting surface. become. Therefore, the square lens can be easily adhered and fixed to the mounting surface of the substrate by using, for example, an ultraviolet curable resin.

According to such a square lens, after molding the preform, it is mounted on the substrate in a state where the optical axis height (distance from the substrate surface) is determined as described above, without performing post-processing such as dicing and polishing. It is possible. As a result, the cost of the lens used for optical communication or the like can be reduced.

Further, when fixing a lens to an optical fiber or a semiconductor laser, downsizing is possible as compared with the case of using a lens barrel or a can for fixing, and it can be used as a mounting component surface-mounted on a substrate like a lens. As a close size, it can be used by adhering to the substrate surface as described above. As a result, it is possible to reduce the thickness of the device including the substrate on which the lens is mounted.

Japanese Unexamined Patent Publication No. 2008-150265

By the way, in the square lens surface-mounted on a substrate as described above, further downsizing and cost reduction are required. However, when the square lens as described above is miniaturized, the effective diameter of the lens becomes small. For example, when the cross section of a quadrangle orthogonal to the optical axis direction of a square lens is a square having a side length of a, the effective diameter of the lens is a or less. Here, if the effective diameter of the lens is too small, for example, it becomes difficult to make most of the light from the semiconductor laser enter the optical fiber, and there is a limit to downsizing when the optical function of the lens is taken into consideration.

The present invention has been made in view of the above circumstances, and is a glass that is provided with a flat portion that abuts on the substrate, can be surface-mounted on the substrate, and can be downsized while suppressing a decrease in effective diameter. It is an object of the present invention to provide a forming lens, a lens forming apparatus, and a lens manufacturing method.

In order to achieve the above object, the glass molded lens of the present invention has a square cylindrical outer peripheral molded surface having four surfaces along the optical axis direction and lens coverings provided at both ends of the outer peripheral molded surface. With a molding surface,
The periphery of the lens-molded surface has a shape joined to the outer peripheral molded surface.
The periphery of at least one lens-molded surface of the two lens-molded surfaces has a shape joined to the outer peripheral molded surface.
The effective diameter of the lens formed on at least one of the two lens-molded surfaces along the diagonal direction of the lens-molded surface is the light of the outer peripheral molded surface. is longer than the length of the shortest side of the four sides of its when regarded as a cross section perpendicular to the axial direction a square,
It is characterized in that plane portions orthogonal to the optical axis are individually formed corresponding to the four corner portions of the lens-molded surface.

According to such a configuration, the effective diameter of the lens is not limited by the length of the four sides of the square lens, but is limited by the diagonal length, and the lens of the glass molded lens. The effective diameter of the lens that functions as a lens can be increased. In this case, the effective diameter of the lens can be increased to the length of the diagonal line. The effective diameter of the conventional square lens is the diameter of the inscribed circle of the quadrangle of the square lens at the maximum, and the portion between the square and the inscribed circle, which is the outer shape of the square lens, does not function as a lens. On the other hand, in the present invention, a range larger than the inscribed circle can be made to function as a lens surface, and a surface of a square lens on the incident side (lens molded surface) and a surface on the reflecting side (lens molded surface) can be used at the maximum. ) Can function as a lens surface. That is, the area of the lens surface can be maximized by cutting off the lens that is the circumscribed circle of the quadrangle that is the outer shape of the square lens to the maximum, and the lens is effective up to the diagonal length of the square of the outer shape of the lens at this time. The diameter can be extended. As a result, substantially the entire surface of the lens-molded surface of the glass-molded lens can be made into a lens surface that effectively functions as a lens, so that the effective effective diameter is substantially larger than that of a conventional square lens.

As a result, when downsizing the glass molded lens, by shortening the lengths of the four sides of the square lens, the effective diameter of the lens becomes too small and the function as a lens becomes insufficient for the purpose of use. Can be prevented. In other words, as compared with the conventional product, the outer shape of the square lens can be reduced while maintaining the required effective diameter, and downsizing can be performed while ensuring the performance as a lens mounted on a substrate for optical communication or the like.

In the configuration of the present invention, at least one lens-molded surface is a convex surface, and the flat surface formed at the four corners of the lens-molded surface is the four corners of the lens-molded surface. preferably Rukoto in comparison with the portion adjacent to the inner having a gentle slope portion the angle formed between the plane becomes smaller orthogonal to the optical axis.

According to such a configuration, when manufacturing a glass-molded lens, for example, when the lens-molded surface is molded by a mold, if the lens-molded surface is a convex surface, the lens-molded surface of the mold is molded. When the lens-molded surface is concave and the lens-molded surface is substantially the entire surface of the portion surrounded by the outer peripheral molded surface of the glass-molded lens, the four corners of the lens-molded surface of the mold have a substantially triangular cross section and the tip. A sharp edge with a sharp edge will be formed. If there is a sharp edge, it may cause damage such as cracks in the mold, and there is a risk that the mold may be chipped due to chipping during lens molding.
Therefore, if the four corners of the mold have no sharp edges, gently inclined portions having a small inclination angle with respect to a plane orthogonal to the optical axis are formed at the four corners of the lens-molded surface of the glass-molded lens. .. The gently inclined portion may be, for example, a flat surface orthogonal to the optical axis, a curved surface instead of a flat surface, or an angle slightly smaller than the angle orthogonal to the optical axis. , As described above, it is formed corresponding to the shape without the sharp edge of the lens forming surface of the mold.

Further, in the configuration of the present invention, it is preferable that the gently inclined portion is a plane orthogonal to the optical axis. According to such a configuration, the sharp edge of the mold for molding the lens-molded surface of the glass-molded lens can be eliminated as described above, and the problem due to the sharp edge can be solved.

Further, in the configuration of the present invention, at least one lens-molded surface is a convex surface, and at least one outer surface of the four outer surfaces constituting the outer peripheral molded surface is joined to the lens-molded surface. It is preferable that at least the central portion of the edge portion is formed in an arc shape having a convex shape.

According to such a configuration, when the glass is molded, the glass thinly protrudes from the clearance between the molds to form a beam-like structure in the glass-molded lens, or the glass-molded lens is cracked from this burr-like structure portion. Etc. can be prevented from occurring.

That is, the cross-sectional shapes of the outer peripheral surfaces of the upper and lower molds in the sleeve are substantially the same as the cross-sectional shapes of the inner peripheral surfaces of the sleeve, but between these inner peripheral surfaces and the outer peripheral surfaces, the upper and lower molds are formed. A clearance that allows the mold and sleeve to move relatively is required. As a result, when the preform is pressed in the sleeve by the upper mold and the lower mold, the glass may be extruded into the clearance to form a burr-like structure. In particular, if the side of the outer surface (outer peripheral surface) of the upper and lower molds on the side where the preform is sandwiched is straight, the center of the ellipse when the pressed preform hits the inner surface of the sleeve and spreads in an elliptical shape. The part easily protrudes to the clearance side.
Here, when the spherical preform is pressed in the sleeve by the upper mold and the lower mold, the preform is large enough to fit into the sleeve when the capacity of the preform and the capacity of the glass molded lens are taken into consideration. It becomes. That is, the preform has a diameter close to the diameter of the inscribed circle of the quadrangular cross section of the sleeve.

Therefore, when the preform is pressed by the upper mold and the lower mold and crushed from above and below, the preform comes into contact with each other at a portion close to the inner surface of the sleeve of the preform, and the contact portion becomes elliptical. .. Here, the outer surface to be the outer peripheral molded surface of the glass-molded lens molded as described above has an arc-shaped side that is convex outward, and correspondingly, at least one of the upper die and the lower die. The side of the outer surface that contacts the inner surface of the sleeve of the mold is recessed in an arc shape, and as described above, the preform that spreads on the inner surface of the sleeve fits in without protruding. It becomes difficult for glass to get in between the upper and lower molds.

Further, in the configuration of the present invention, on the outer surface formed in an arc shape in which at least the central portion of the edge portion is convex, a straight line portion is continuously formed in the central portion formed in the convex arc shape. Is preferable. According to such a configuration, the structure corresponding to the above-mentioned gently sloping portion is provided on the outer surface, and the effect of providing the above-mentioned gently sloping portion can be obtained.

Further, in the configuration of the present invention, it is preferable that the four corners of the lens-molded surface are provided with an arc shape centered on the optical axis.

According to such a configuration, the position of the optical axis can be detected from the center of the arc even if the optical axis is shifted to manufacture the glass molded lens. When the optical axis coincides with the central axis of the outer peripheral molded surface of the square columnar shape, for example, when mounting the glass molding lens on the substrate, the substrate may come into contact with any of the four outer surfaces of the outer peripheral molded surface. The distance from the surface to the optical axis is the same, but when the optical axis is shifted with respect to the central axis of the outer peripheral molded surface to form the glass molded lens, any surface of the outer peripheral molded surface comes into contact with the substrate surface. The distance (height) of the optical axis from the substrate surface differs depending on whether or not the optical axis is used. At this time, by finding the centers of the arcs at the four corners of the lens molded surface as described above, the distance from each outer surface of the outer peripheral molded surface to the optical axis can be known, so that the optical axis position of the glass molded lens is correct. It can be installed on the substrate so as to be. For the arc, for example, the effective diameter of the lens in the diagonal direction is slightly shorter than the diagonal, and the arc-shaped outer edges of the effective surface of the lens are provided at the four corners of the lens-molded surface, or the sharp edges are chamfered. When the gently inclined portion is formed, the arc surface at the boundary between the gently inclined portion and the lens surface can be used.

Further, in the configuration of the present invention, the outer peripheral edge of the lens-molded surface has an inclination angle with respect to the plane orthogonal to the optical axis of the portion of the lens-molded surface inside the outer peripheral edge with respect to the plane. It is preferable that the chamfered portion having a small inclination angle is provided.

According to such a configuration, when the peripheral edge of the lens molding surface of the mold has an edge shape, the glass molding lens is provided with a shape corresponding to the chamfered shape, and the edge of the mold is chamfered. As a result, the durability of the mold can be improved and the cost can be reduced.

The lens molding apparatus of the present invention is a lens molding apparatus for molding the glass-molded lens.
A first mold having an internal space penetrating in a substantially square columnar shape to form the outer peripheral molded surface, and the first mold inserted into the internal space of the first mold from opposite directions. It is provided with a second mold and a third mold having a substantially square columnar shape, which is substantially the same as the internal space of the above.
A lens forming surface for forming the lens-molded surface is provided at the tips of the second mold and the third mold.

According to such a configuration, the effective diameter of the lens can be increased even if the lens diameter of the square lens is reduced, and it is possible to suppress the problem of the lens characteristics of the glass molded lens due to the miniaturization. That is, downsizing can be achieved while ensuring the performance of the lens mounted on the substrate and condensing the light emitted from the laser diode on the substrate.

In the lens molding apparatus having the above configuration of the present invention, at least one of the lens molding surfaces is a concave surface, and the four corner portions of the lens molding surface are adjacent to the inside of the four corner portions of the lens molding surface. In comparison, it is preferable that a non-edge portion having a smaller angle with the plane orthogonal to the central axis of the lens molding surface is formed.

According to such a configuration, sharp edges at four corners of the lens forming surface of the second mold and the third mold for forming the lens surface as an effective convex surface on substantially the entire surface of the lens molded surface of the glass molded lens are removed. By doing so or not providing sharp edges, it is possible to prevent the four corners of the lens molding surface of the mold from being chipped due to chipping or being damaged such as cracks.

Further, in the lens molding apparatus having the above configuration of the present invention, it is preferable that the non-edge portion is a plane orthogonal to the central axis. According to such a configuration, as described above, the lens molded surface has no sharp edges, the structure can be suppressed from becoming complicated, and the cost increase can be suppressed.

Further, in the lens molding apparatus having the above configuration of the present invention, it is preferable that the four corners of the lens molding surface are provided with an arc shape centered on a predetermined position of the lens molding surface.

According to such a configuration, for example, even when the position corresponding to the optical axis of the glass-molded lens to be molded is shifted with respect to the central axis of the outer peripheral molded surface as a predetermined position of the lens-molded surface. , The position corresponding to the optical axis of the lens forming surface of the second mold and the third mold can be obtained by the center of the arc. In the lens forming apparatus, for example, the first mold, the second mold, and the second mold When combining the molds, the positions corresponding to the optical axes can be aligned between the second mold and the third mold.

The lens manufacturing method of the present invention is a lens manufacturing method using the above-mentioned lens molding apparatus.
A spherical preform made of a glass material for an optical element and heat-softened between the lens-molded surface of the second mold and the lens-molded surface of the third mold in the internal space of the first mold. Place and
The preform is pressed into the glass-molded lens by bringing the second mold and the third mold relatively close to each other in the first mold.

According to such a lens manufacturing method, since a spherical preform is supplied to the above-mentioned lens molding apparatus to form a glass-molded lens, the same action and effect as those of the above-mentioned glass-molded lens and lens-molding apparatus can be obtained. can. Further, when the lens molding surface is a concave surface, when the preform is pressed by the second mold and the third mold, the preform moves to the most recessed central portion of the lens molding surface, and the preform is lens-molded. Since the preform is pressed and molded while being aligned with a predetermined position on the surface, when molding many glass-molded lenses, the preform is regarded as a glass-molded lens based on the same deformation of the softened glass. Therefore, in each glass molded lens, the lens characteristics are stabilized, and the quality and the yield can be improved.

According to the present invention, downsizing and cost reduction can be achieved while maintaining the performance of the glass molded lens surface-mounted on the substrate.

It is a figure which shows the glass molding lens of 1st Embodiment of this invention, (a) is a front view, (b) is a cross-sectional view of AA of (a), (c) is a side view. The same is the figure which shows the 2nd mold (third mold) of the lens molding apparatus for molding a glass molding lens, (a) is a front view, (b) is a BB cross section of (a). FIG. 3C is a side view. It is a cut end view which shows the outline of the mold of the lens molding apparatus. It is a cut end view which shows the outline of the mold of the lens molding apparatus. It is a figure which shows the glass molding lens of the 2nd Embodiment of this invention, (a) is a front view, (b) is a CC sectional view of (a), (c) is a side view. The same is the figure which shows the 2nd mold (third mold) of the lens molding apparatus for molding a glass molding lens, (a) is a front view, (b) is a DD cross section of (a). FIG. 3C is a side view.

Hereinafter, the first embodiment of the present invention will be described with reference to the drawings.
The glass-molded lens 1 of the present embodiment shown in FIGS. 1 (a) to 1 (c) is made of a glass material for an optical element and is pressurized by heating and softening a preform which has become spherical by spherical processing. It is molded by In addition, in a mold or the like used for manufacturing a glass molded lens, in order to prevent damage such as chipping or cracking at the edge portion, a curved surface or a flat surface having a radius of curvature R is provided on the edge portion as a chamfer to prevent the edge. However, in the first embodiment, the chamfering of the mold and the shape of the glass-molded lens based on the chamfering will be omitted, and the gold will be described in the second embodiment described later. The chamfering of the mold and the shape of the glass molded lens based on the chamfering will be described. Here, FIG. 1A is a front view of the glass-molded lens 1 and shows a lens-molded surface 5 on the side where light is emitted (lens-molded surface 4 on the side where light is incident). FIG. 1B is a cross-sectional view of an optical axis portion along the optical axis of the glass molded lens 1. FIG. 1C is a side view of the glass molded lens 1, in which a solid line indicates an end face and a broken line indicates a portion other than the end face.

The glass-molded lens 1 has an outer peripheral surface to be molded whose outer peripheral surface along the optical axis direction is formed into a square cylinder. Further, the four corners of the outer peripheral molded surface 2 having a square cylinder shape, for example, have a rounded shape so that the preform does not completely reach the corners of the mold during molding. In addition, the cross section orthogonal to the optical axis of the outer peripheral surface to be molded has a square shape, ignoring the roundness of the corners, but it is not a square shape but a rectangular shape in which the lengths of two of the four sides are different. There may be.

Further, the outer peripheral surface to be molded 2 is formed in a square cylinder shape from the four outer surfaces 3, and each outer surface 3 has two parallel linear sides along the optical axis direction as shown in FIG. 1 (c). , The shape is surrounded by two sides formed of a substantially arc-shaped curve intersecting the direction of the optical axis, and each of the two sides having a substantially arc shape is a curve that is convex toward the outside. Each outer surface 3 has a substantially quadrangular shape from two straight lines along the optical axis and two substantially arc-shaped curves intersecting the optical axis, but the two straight lines correspond to the two arc-shaped curves. It is short, and each outer surface 3 has a shape close to an ellipse due to two arc-shaped curves. In this embodiment, the left and right ends of the two arcuate sides of the outer surface 3 are formed by the outer flat surface portion 6 having the effective lens diameter (R) along the diagonal line of the lens molded surface 5 (lens molded surface 4). It has a linear shape orthogonal to the optical axis, but as described above, it has a curved shape at the corners where the preform cannot be completely filled. The effective lens diameter (R) on the diagonal line of the lens-molded surface 5 (lens-molded surface 4) is the length of one side when the lens-molded surface 5 (lens-molded surface 4) is regarded as a square. It is longer than (D) and has a maximum diagonal length. When the effective lens diameter (R) on the diagonal of the lens-molded surface 5 (lens-molded surface 4) is the same as the diagonal, a curved surface is formed on the entire surface of the lens-molded surface 5 (lens-molded surface 4). It is formed so that the flat surface portion 6 disappears from the corner portion. However, in reality, when the curved surface of the lens is formed up to the corners, sharp edges that are likely to be worn or chipped are generated on the mold side. Therefore, by eliminating the sharp edges, the lens molded surface 5 is formed. A flat surface portion 6 is formed at a corner portion of the (lens molded surface 4). The flat surface portion 6 is, for example, a plane orthogonal to the optical axis, but may be a gentle curved surface or an angle slightly deviated from 90 degrees with respect to the optical axis. It is a gently sloping portion that is gently inclined with respect to a plane that is orthogonal to the unsharp optical axis or a plane that is orthogonal to the optical axis. The gently sloping portion includes a plane orthogonal to the optical axis and also includes a gentle curved surface. Here, the effective lens diameter represents the size of a surface (lens surface) capable of exhibiting a desired lens function in terms of diameter.

Further, at both ends of the outer peripheral molded surface 2 of the glass molded lens 1, light is emitted from the lens molded surface 4 on the side where light is incident so as to close the openings at both ends of the square tubular outer peripheral molded surface 2. A lens-molded surface 5 on the emitting side is provided.
These lens-molded surfaces 4 and 5 have a lens surface and serve as an incident surface and an exit surface. In the present embodiment, the lens-molded surfaces 4 and 5 are convex surfaces. The lens-molded surface 4 and the lens-molded surface 5 may have substantially the same shape or different shapes. Further, the glass molded lens 1 is molded from a spherical preform, and the lens molded surfaces 4 and 5 are aspherical lenses.

As shown in FIG. 1, each lens molded surface 4 and 5 has a convex lens surface, and the effective lens diameter (R) along the diagonal direction of the cross section of the glass molded lens 1 is the cross section. It is longer than the shortest side (D) of each side. The length of the effective diameter on the diagonal line may be substantially the same as the length of the diagonal line. Therefore, on the lens-molded surfaces 4 and 5, a circular lens surface inscribed in the outer shape of the quadrangle is not formed. It may be a lens having a shape cut out by a square of the outer shape of the molded lens 1. In the lens molded surface 5 (lens molded surface 4) of FIG. 1, the effective lens diameter on the diagonal line is longer than one side of the lens molded surface 5 (lens molded surface 4) and shorter than the diagonal line. ..
That is, for each lens molded surface 4 and 5 having a square outer shape, the effective diameter of the lens on the diagonal line is approximately the diagonal length, and the lens is effectively formed on substantially the entire surface of the lens molded surface 5 (lens molded surface 4). It is a surface, and if it is approximately the same size as a conventional square lens, the effective diameter of the lens is substantially larger. However, the lens-molded surfaces 4 and 5 are provided with substantially triangular flat surface portions 6 at the corner portions (corner portions) of the four corners. Therefore, a portion having a slightly smaller area than the entire surface of the lens-molded surfaces 4 and 5 is an effective lens surface. In this embodiment, the plane portion 6 is a plane orthogonal to the optical axis. The plane as the flat surface portion 6 has an effective lens diameter on the lens-formed surfaces 4 and 5 shorter than the diagonal line of the substantially square lens-formed surfaces 4 and 5 and longer than the length of one side on the substantially square. The mold surface is formed, and the four corner portions (corner portions) of the lens-molded surfaces 4 and 5 are formed as a flat surface outside the effective lens diameter. Alternatively, the shape of the mold surface corresponds to removing the sharp edges at the four corners of the mold after making the effective diameter of the lens substantially the same as the diagonal lines of the lenses to be molded surfaces 4 and 5. ..

Further, the inner side of the flat surface portion 6, that is, the boundary portion between the flat surface portion 6 and the curved surface as a lens surface that functions as a lens adjacent to the flat surface portion 6 is an arc 7. The center positions of the radii of curvature of the four arcs 7 at the four corners overlap one point and coincide with the position of the optical axis, and this point is designated as the coincidence point 8. The arc 7 indicates the effective diameter of the lens at the corner portion when the above-mentioned flat surface portion 6 is outside the effective diameter of the lens as described above, and is a part of one circle. Therefore, the center positions of the radii of curvature of these arcs 7 coincide with each other, and the coincidence points 8 are the optical axis positions of the glass molded lens 1. Therefore, the position of the optical axis can be found by finding the center of the radius of curvature of the arc 7. Therefore, even when the optical axis position is designed to be shifted from the center position of the glass molded lens 1, the optical axis position can be specified from the arc 7.

As shown in FIG. 1 (b), in the cross section of the optical axis portion of the glass molded lens 1 along the optical axis, the portions of the lens molded surfaces 4 and 5 are basically arcuate curved surfaces, and the convex lens. However, the diagonal effective diameter of the glass molded lens 1 is wider than the left-right width of the cross section as the effective diameter in the cross section shown in FIG. 1 (b). As shown in FIGS. 1 (a) and 1 (c), the four outer surfaces 3 around the glass molded lens 1 are basically surfaces on the outer peripheral side of the convex lens along the optical axis direction and orthogonal to the radial direction. In the glass molded lens 1, the above-mentioned flat surface portions 6 are provided at the four corners, and as described above, the four corners of the glass molded lens are rounded without the preform spreading to these portions. Since the shape is tinged with, the shape is such that both ends of the arc-shaped side are provided with a linear portion instead of an arc-shaped portion and a rounded portion on the end side thereof.

In such a glass-molded lens 1, even if the length of each side of the cross section of the outer peripheral surface to be molded 2 is shortened by downsizing, the effective effective diameter of the glass-molded lens 1 becomes too small. It is possible to suppress, for example, even when a square lens having a side of about 3 mm or less (for example, 1 mm) is manufactured as the glass molded lens 1, it can be used as a lens with a sufficient effective diameter secured. It is possible, and even if one side is about 1 mm, it can sufficiently function as a lens.

Next, a lens molding apparatus for molding the glass molding lens 1 will be described with reference to FIGS. 2 (a) to 2 (c) and FIGS. 3 and 4. The lens molding apparatus is formed by applying pressure to a preform that has been softened by heating, and includes a first mold 11, a second mold 12, and a third mold 13 as shown in FIGS. 3 and 4. The first mold 11 is a square sleeve and includes a square columnar internal space 21 penetrating the inside. The cross section of the internal space 21 is square. The outer peripheral molded surface 2 of the glass molding lens 1 is molded into a square cylinder shape by the inner peripheral molding surface which is the inner surface of the square columnar internal space 21.

The second mold 12 is an upper mold arranged on the upper side and a movable mold that moves up and down. The lower end of the second mold 12 is the first insertion portion 22 to be inserted into the internal space 21 of the first mold 11, and the cross-sectional shape of the first insertion portion 22 is the cross-sectional shape of the internal space 21. However, the outer shape of the first insertion portion 22 is reduced by the amount of clearance. The front end surface (lower end surface) of the first insertion portion 22 is the lens forming surface 14.

The third mold 13 is a lower mold arranged below the second mold 12 and is a fixed mold that does not move up and down. The upper end portion of the third mold 13 is a second insertion portion 23 that is inserted into the internal space 21 of the first mold 11, and the cross-sectional shape of the second insertion portion 23 is the cross-sectional shape of the internal space 21. However, the outer shape of the second insertion portion 23 is reduced by the amount of the clearance. The tip surface (upper end surface) of the second insertion portion 23 is the lens molding surface 15.
2 (a) to 2 (c) show the first insertion portion 22 of the second mold 12 (the second insertion portion 23 of the third mold), and FIG. 2 (a) is a front view. 2 (b) is a cross-sectional view taken along the central axis. FIG. 2C is a side view. The cross section is a curved line that is a concave cross section over the entire width, but in the side view, there are straight lines corresponding to the flat surface portion (non-edge portion) 16 described later at both left and right ends, and the space between them is It is a curve corresponding to the concave surface.

The lens-molded surfaces 14 and 15 have a surface shape corresponding to the lens-molded surfaces 4 and 5 of the glass-molded lens 1, and are concave surfaces. The lens forming surfaces 14 and 15 are provided with a concave surface corresponding to the lens surface in a quadrangle as a cross-sectional shape of the first insertion portion 22 or the second insertion portion 23. Here, the lens molding surfaces 14 and 15 of the dies 12 and 13 have concave surfaces that correspond to the lens molded surfaces 4 and 5 of the glass molding lens 1 and that form a portion within the effective diameter of the lens. A lens effective diameter longer than one side of the rectangular lens molding surfaces 14 and 15 is set along the diagonal direction of the molding surfaces 14 and 15, but the lens effective diameter is larger than the diagonal length of the lens molding surfaces 14 and 15. When it is short, the flat surface portion (non-edge portion) 16 is formed at the four corners of the lens forming surfaces 14 and 15 of the second mold 12 and the third mold 13.

When the effective lens diameter is the diagonal length of the lens forming surfaces 14 and 15, the entire lens forming surfaces 14 and 15 become concave, but sharp edges are formed at the four corners of the concave surface. Assuming that the shape is a plane orthogonal to the optical axis of the glass-molded lens 1 molded in the 1st to 3rd molds 11 to 13 and the sharp edges are removed, the lens-molding surfaces 14 and 15 are formed in substantially the same manner as in the above case. The flat surface portion 16 is provided with, for example, a flat surface orthogonal to the optical axis at the corner portions of the four corners. The flat surface portion 16 is not limited to a plane orthogonal to the optical axis, and may be a curved surface or may be slightly deviated from the state orthogonal to the optical axis. However, on the lens forming surfaces 14 and 15, the inclination angle of the plane portion 16 with respect to the plane orthogonal to the optical axis must be smaller than the inclination angle of the portion adjacent to the inside of the plane portion 16 with respect to the plane orthogonal to the optical axis. In this embodiment, the optical axis corresponds to the central axis of the first insertion portion 22 of the second mold 12 (the second insertion portion 23 of the third mold). This central axis is the same as the central axis of the lens forming surfaces 14 and 15, and when the first insertion portion 22 and the second insertion portion 23 are inserted into the internal space 21 of the first mold 11, they are centered. The axes are almost aligned.

Further, the lens forming surfaces 14 and 15 of the second mold 12 and the third mold 13 are adjacent to the inside of the flat surface portion 16 which is a plane substantially orthogonal to the optical axis by providing the flat surface portions 16 at the four corner portions thereof. An arc 17 is formed as a boundary with the portion to be formed. The centers based on the radius of curvature of each arc 17 of the flat surface portions 16 at the four corners of the lens forming surfaces 14 and 15 coincide with each other at the coincidence point 18 at the center of the lens forming surfaces 14.15.

The coincidence point 18 is a portion corresponding to the optical axis of the glass molded lens 1 in this embodiment. The coincidence point 18 coincides with the central axis of the first insertion portion 22 of the second mold 12, and coincides with the central axis of the second insertion portion 23 of the third mold 13. Further, the coincidence point 18 which is the center position of each arc 17 is a position corresponding to the optical axis position of the glass-molded lens 1 to be molded. When the portion for forming the optical axis of the glass molding lens 1 is shifted with respect to the central axes of the first insertion portion 22 and the second insertion portion 23, the position for forming the optical axis from the arc 17 is determined. Can be sought.
When assembling the molding apparatus by assembling the first mold 11, the second mold 12, and the third mold 13, the first mold 11 to the third mold 13 are based on the above-mentioned coincidence point 18. In particular, by determining the positions of the second mold 12 and the third mold 13, the lens forming apparatus can be assembled accurately, and finally the glass forming lens 1 in which the optical axis is arranged at a desired position is obtained. be able to.

A lens manufacturing method using the above-mentioned lens molding apparatus will be described with reference to FIGS. 3 and 4.
As shown in FIG. 3, the upper mold 12 is moved upward, and the upper opening of the internal space 21 of the first mold 11 as a square sleeve is opened. The second insertion portion 23 of the third mold 13, which is the lower mold, is inserted from the opening on the lower side of the internal space 21 of the first mold 11. As a result, the lower opening of the internal space 21 of the first mold 11 is closed by the second insertion portion 23 of the third mold 13.

Next, the spherical preform 71 is inserted and placed on the lens forming surface 15 of the third mold 13 in the internal space 21 from the upper opening of the first mold 11 in the opened state. The first mold 11, the second mold 12, the third mold 13, and the preform 71 are in a heated state, and the preform 71 is in a moldable state.

Further, the outer diameter of the preform 71 is slightly shorter than the inner diameter (side length) of the internal space 21, and is large enough to fit into the internal space.
Next, the second mold 12 which is the upper mold is moved downward, and the preform 71 is sandwiched between the second mold 12 and the third mold 13 and pressed to form.
At this time, the preform 71 is in a state of being relatively pressurized from above and below in the internal space 21, and is molded so as to be crushed from above and below.
At this time, the shapes of the lens-molded surface 14 of the second mold 12 and the lens-molded surface 15 of the third mold 13 are transferred to the portions to be the lens-molded surfaces 4 and 5 of the preform 71. At this time, the preform 71 is crushed so as to bulge outward in the direction orthogonal to the optical axis, but immediately hits the four inner surfaces of the internal space 21 of the first mold 11 in the direction orthogonal to the optical axis. It becomes a long ellipse and is molded so that this ellipse expands.
Here, the inner surface of the internal space 21 of the first mold 11 does not come into contact with the outer peripheral surface of the first insertion portion 22 of the second mold 12, and further, the second insertion portion 23 of the third mold 13 The portion that does not come into contact with the outer peripheral surface of the glass molding lens 1 has a shape close to an ellipse as described above, and this portion constitutes the outer peripheral molded surface 2 of the glass molding lens 1. In this portion, the preform 71 pressurized as described above expands in the shape of an ellipse. As described above, in this portion, the inner surface of the internal space 21 and the first insertion portion 22 and the second insertion portion 22 are inserted. Since the outer surfaces of the portions are not in contact with each other, the preform is prevented from entering between them to form a beam-like structure, and the preform 71 stays until the molding of the glass molding lens 1 is completed. It is possible to suppress entry into the portion where the inner surface of the internal space 21 and the outer surfaces of the first insertion portion 22 and the second insertion portion 23 are in contact with each other, and it is possible to suppress the formation of the above-mentioned beam-like structure. In other words, the preform 71 is pressurized and filled in the space formed by the mold until the beam-like structure is generated, so that it is not necessary to perform vacuum forming.

Further, according to the lens molding method using such a lens molding apparatus, it is possible to further downsize while securing the effective lens surface area of the glass molded lens 1 which is a square lens as described above. Glass molded lenses can be manufactured. Further, since the flat surface portion 16 having a shape obtained by removing the sharp edges at the four corners of the concave lens forming surfaces 14 and 15 of the second mold 12 and the third mold 13 is provided, the second mold 12 by chipping or the like is provided. And the damage of the third mold 13 can be suppressed.

The glass-molded lens 1 of the present embodiment can be used for an optical communication device, an optical waveguide, a head-up display, and the like, and can be particularly preferably used as a lens surface-mounted on a substrate.

Next, a second embodiment of the present invention will be described. The glass molding lens 31, the lens molding apparatus, and the lens manufacturing method of the second embodiment are substantially the same as those of the glass molding lens 1, the lens molding apparatus, and the lens manufacturing method of the first embodiment, but the lens molding apparatus. The chamfering portions 49 are provided on the four sides surrounding the outer periphery of the lens forming surface 44 of the second mold 42 and the lens forming surface 45 of the third mold 43, which is different from the first embodiment. As a result, the shape of the glass molded lens 31 is different from that of the first embodiment. Other configurations are substantially the same in the first embodiment and the second embodiment.

Before explaining the glass molded lens 31 of this embodiment, the second mold 42 (third mold 43) shown in FIG. 6 will be described. The second mold 42 (third mold 43) has a first insertion portion 52 (second insertion portion 53) inserted into the internal space 21 of the first mold 11 as in the first embodiment. The tip surface thereof is a lens molding surface 44 (lens molding surface 45). The lens molding surface 44 (lens molding surface 45) is a concave surface corresponding to the lens surface of the convex lens, but the flat surface portion 46 is formed at the four corners of the substantially quadrangular concave surface as in the first embodiment. ing. The flat surface portion 46 is the outer surface of the lens effective diameter when the effective diameter of the lens is shorter than the diagonal length of the lens molding surface 44 (lens molding surface 45) as described above, and the lens effective diameter is the diagonal line described above. This is the part where the sharp edge is removed in the same case as. In the production of the second mold 42 and the third mold 43, the four corners are used, for example, as a part of chamfering after the diagonal length is set as the effective diameter of the lens and the entire lens forming surfaces 44 and 45 are made concave. The flat surface portion 46 may be formed by removing the sharp edge of the lens, or the effective diameter of the lens may be shorter than the diagonal line so that the four corners of the lens forming surfaces 44 and 45 do not have sharp edges at the design stage. It may be manufactured so as to form a portion 46.
Further, as in the first embodiment, an arc 47 is provided at the boundary portion between the flat surface portion 46 and the concave surface, and the centers of the radii of curvature of the arc 47 at each of the four corners coincide with each other, and the coincidence point 48 is formed. , The position corresponding to the optical axis of the glass molded lens 31. In this embodiment, the chamfered portion 49 is provided in a portion between the flat portions 46 of the four sides surrounding the lens forming surface 44 (lens forming surface 45). The chamfered portion 49 is a portion where an edge is generated by forming a concave surface corresponding to the lens surface up to the four sides of the lens forming surface 44 (lens forming surface 45), and the edge is eliminated by chamfering. This is to prevent the edge portion of the second mold 42 (third mold 43) from being chipped or cracked. On the lens molding surface 44 (lens molding surface 45), the flat surface portion 46 was substantially triangular in the first embodiment, but in the second embodiment, a strip-shaped chamfered portion is formed on the side portion connected to the four corners. By providing 49, it has a substantially pentagonal shape. Further, each side between the flat surface portions 46 is a curved (arc-shaped) edge, and in the chamfered state, the chamfered portion 49 of each side is a band-shaped curved surface that bends in an arc shape. That is, each side of the outer edge of the lens molding surface 44 (lens molding surface 45) is a strip-shaped curved surface that is narrow in width and curved in an arc shape in the length direction. Since the edge portion of the second mold 42 (third mold 43) has been removed to form a gentle surface, damage that is likely to occur at the edge can be suppressed.

The glass molding lens 31 is formed by using the second mold 42 and the third mold 43 in the same manner as in the first embodiment. As shown in FIG. 5, the glass molded lens 31 of the second embodiment has a shape corresponding to the chamfered portion 49 of the above-mentioned molds 42 and 43. The structure is the same as that of the first embodiment except for the portion corresponding to the chamfered portion 49. The glass-molded lens 31 has a square cylindrical outer peripheral molded surface 32 composed of four outer surfaces 33 on the outer peripheral portion as in the first embodiment. Lens molded surfaces 34 and 35, which are incident surfaces or exit surfaces of the lens, are provided at both ends of the outer peripheral molded surface 32, respectively. Further, at the four corners of the lens-molded surfaces 34 and 35, a flat surface portion 36 corresponding to the above-mentioned flat surface portion 46 of the mold is provided, and the boundary between the flat surface portion 36 and the lens surface is an arc 37. ing. The center positions of the radius of curvature of the arc 37 at each of the four corners coincide with each other, and the coincidence point 38 overlaps with the optical axis.

The glass-molded lens 31 is provided with a chamfered portion 39 corresponding to the chamfered portion 49 of the second mold 42 and the third mold 43 described above. The chamfered portion 39 is formed on the outer peripheral edge of the convex surface of the glass molded lens 31 by removing the sharp edge portion along the outer edge in the second mold 42 and the third mold 43. The angle with respect to the orthogonal plane is small, but since the original edge portion is an arc-shaped curve, it does not become a plane, and the chamfered portion 39 is a strip-shaped curved surface that bends in an arc shape like the chamfered portion 49 described above. It has become. In the chamfered portion 39, the inclination angle with respect to the plane orthogonal to the optical axis is gentler than the lens surface in the vicinity of the inside of the chamfered portion 39.
According to the second embodiment, the durability of the second mold 42 and the third mold 43 can be improved, and the manufacturing cost can be reduced.

In each of the above-described embodiments, basically, the center of the glass-molded lenses 1 and 31 (the point in the lens through which the optical axis passes) and the center of the quadrangle that is the outer shape of the glass-molded lens (the intersection of the two diagonal lines). Although they are supposed to match (overlap) with each other, they may be different without matching their positions. That is, the position of the optical axis may be shifted with respect to the intersection of the two diagonal lines.

1, 31 Glass molded lens 2, 32 Outer surface molded surface 3, 33 Outer surface 4, 34 Lens molded surface 5, 35 Lens molded surface 6, 36 Flat surface portion 7, 37 Arc 8, 18, 38, 48 Coincidence point 11 1st mold 12, 42 2nd mold 13, 43 3rd mold 14, 44 Lens molding surface 15, 45 Lens molding surface 16, 46 Flat surface portion (non-edge portion)
17, 47 Arc 21 Internal space 22, 52 First insertion part 23, 53 Second insertion part 71 Preform

Claims (12)

A square cylindrical outer peripheral molded surface having four surfaces along the optical axis direction and a lens molded surface provided at both ends of the outer peripheral molded surface are provided.
The periphery of the lens-molded surface has a shape joined to the outer peripheral molded surface.
The periphery of at least one lens-molded surface of the two lens-molded surfaces has a shape joined to the outer peripheral molded surface.
The effective diameter of the lens formed on at least one of the two lens-molded surfaces along the diagonal direction of the lens-molded surface is the light of the outer peripheral molded surface. is longer than the length of the shortest side of the four sides of its when regarded as a cross section perpendicular to the axial direction a square,
A glass-molded lens characterized in that flat surfaces orthogonal to the optical axis are individually formed corresponding to the four corners of the lens-molded surface. At least one lens-molded surface is convex, and the flat surface formed at the four corners of the lens-molded surface is compared with a portion of the lens-molded surface adjacent to the inside of the four corners. The glass-molded lens according to claim 1, further comprising a gently inclined portion having a small angle formed with a plane orthogonal to the optical axis. The gentle slope portion, the glass molded lens according to claim 2, characterized in that it comprises a curved surface that is inclined relative to a plane perpendicular to the optical axis. At least one lens-molded surface is a convex surface, and at least one outer surface of the four outer surfaces constituting the outer peripheral molded surface has a convex at least a central portion of an edge portion to be joined to the lens-molded surface. The glass-molded lens according to any one of claims 1 to 3, wherein the lens is formed in an arc shape. A claim that the outer surface is formed in an arc shape in which at least the central portion of the edge portion is convex, and a straight line portion is continuously formed in the central portion formed in the convex arc shape. 4. The glass molded lens according to 4. The glass-molded lens according to any one of claims 1 to 5, wherein an arc shape centered on an optical axis is provided at four corners of the lens-molded surface. The outer peripheral edge of the lens-molded surface is chamfered so that the tilt angle with respect to the plane is smaller than the tilt angle of the portion of the lens-molded surface inside the outer peripheral edge with respect to the plane orthogonal to the optical axis. The glass-molded lens according to any one of claims 1 to 6, wherein the portion is provided. A lens molding apparatus for molding the glass molding lens according to any one of claims 1 to 7.
A first mold having an internal space penetrating in a substantially square columnar shape to form the outer peripheral molded surface, and the first mold inserted into the internal space of the first mold from opposite directions. It is provided with a second mold and a third mold having a substantially square columnar shape, which is substantially the same as the internal space of the above.
A lens molding apparatus characterized in that a lens molding surface for molding the lens-molded surface is provided at the tips of the second mold and the third mold. At least one of the lens molding surfaces is concave, and at the four corners of the lens molding surface, on the central axis of the lens molding surface as compared with the portion of the lens molding surface adjacent to the inside of the four corners. The lens molding apparatus according to claim 8, wherein a non-edge portion having a small angle formed with an orthogonal plane is formed. The lens molding apparatus according to claim 9, wherein the non-edge portion is a plane orthogonal to the central axis. The lens molding according to any one of claims 8 to 10, wherein the four corners of the lens molding surface are provided with an arc shape centered on a predetermined position of the lens molding surface. Device. A lens manufacturing method using the lens molding apparatus according to any one of claims 8 to 11.
A spherical preform made of a glass material for an optical element and heat-softened between the lens-molded surface of the second mold and the lens-molded surface of the third mold in the internal space of the first mold. Place and
A lens manufacturing method characterized in that the preform is pressed to obtain the glass molded lens by bringing the second mold and the third mold relatively close to each other in the first mold.

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