WO2010050651A1

WO2010050651A1 - Glass molding press machine for manufacturing a plurality of coupling lenses

Info

Publication number: WO2010050651A1
Application number: PCT/KR2009/000124
Authority: WO
Inventors: Sang Do Kang; Soo Kyung Lee; Kook Hyun Yang; Hee Su Kim; Seung Jun Baek
Original assignee: Agoptics Co Ltd
Current assignee: Agoptics Co Ltd
Priority date: 2008-10-27
Filing date: 2009-01-09
Publication date: 2010-05-06
Anticipated expiration: 2011-04-27
Also published as: JP2012506836A; JP5327565B2

Abstract

The present invention relates to a glass molding press machine for manufacturing a plurality of coupling lenses. The glass molding press machine includes an upper die including an upper holder and a plurality of upper cores; a lower die including a lower holder and a plurality of lower cores; and an up-down driving unit which drives the upper die up or down relative to the lower die. An intermediate die is disposed between the upper die and the lower die and has fixing holes which are formed at locations corresponding to the plurality of upper cores and the plurality of lower cores, wherein the lens holder is inserted into and fixed to the fixing hole during a press working, and an intermediate die guide pin couples the intermediate die to the upper die and the lower die. The glass molding press machine can manufacture a plurality of coupling lenses by the press working of one time.

Description

GLASS MODLING PRESS MACHINE FOR MANUFACTURING A PLURALITY OF COUPLING LENSES

The present invention relates to a glass molding press machine, and more particularly, to a glass molding press machine that at least one fixing hole which at least one lens holder is inserted into and fixed to is formed in an intermediate die disposed between an upper die and a lower die and so a plurality of coupling lenses can be manufactured by a press working of one time.

A mold is used to produce an injection product by processing and molding using properties of a material such as plasticity, malleability and fluidity and is commonly made of a metal material. A mold is classified into a press mold, a plastic mold, a die-casting mold, a casting mold, a forging mold, a glass mold, and a powder metallurgy mold according to its usage. Such a mold is widely used to produce, for example, a home appliance, an optical machine, a transportation machine, an industrial machine, an electrical machine, a glass container, a construction material, a toy, and miscellaneous goods. The present invention relates to a press mold among the above-listed molds, particularly, a glass molding press machine which is used to manufacture a coupling lens employed in an optical machine.

A press mold is a machine which produces various shapes by applying compressive force to a metal material such as sheet steel to be plastically deformed and performing processes such as bending, shearing and contraction. A press machine can process a metal material such as sheet steel without heating and is thus widely used. A glass molding press machine manufactures an optical glass lens by applying compressive force to a mold core which has a shape and toughness of a sub-nanometer degree at a high temperature which is close to a glass transition temperature and a glass yield point to thermally deform an optical glass material and copying an optical surface which is a shape of the mold core to the material. Such a glass molding press machine is divided into a batch type that a mold is fixed to a press and a progressive type that a press working is performed while a mold is moving and is used to produce an aspheric glass lens.

FIGs. 1A and 1B show a conventional glass molding press machine which is used to manufacture a coupling lens. Referring to FIGs. 1A and 1B, if a coupling lens is manufactured by the conventional glass molding press machine of FIGs. 1A and 1B, one coupling lens is pressed and manufactured by one glass molding press machine 2. For example, in the conventional glass molding press mold 2, one upper core is formed in an upper die, and one lower core is formed in a lower die, and so one coupling lens is manufactured by a press working of one time.

In more detail, a lens holder in which a shape of a predetermined dimension is previously formed by a cutting process is installed in the lower core, and a lens glass material is inserted into the inside diameter of the lens holder. Then, the upper core is moved down to pressurize the glass material. As a result, the pressurized glass material becomes one body inside the lens holder, and is molded in a form of a spherical convex lens, whereby a coupling lens is manufactured.

In summary, since the conventional glass molding press machine manufactures one coupling lens through a press working of one time, a coupling lens manufacturing time is lengthy.

Also, in the conventional glass molding press machine, if either of the upper core and the lower core for molding a coupling lens gets destroyed or deformed, a press working should be stopped for replacement, so that not only work efficiency is greatly lowered, but also an additional cost occurs, leading to high cost.

Moreover, the upper core or the lower core may get deformed due to a long time press working, and when the lens holder is manually or automatically placed inside the glass molding press machine, a bottom surface which is a mounting reference surface of the lens holder may be improperly placed inside the glass molding press machine. Therefore, since a norm such as a location of a lens coupled to the inside of the lens holder is not identical, coupling lens manufactured are different in norm and characteristics. Therefore, a percent defective of the coupling lens is increased, and in the worst case, all of coupling lens manufactured may be discarded, leading to low reliability.

It is an object of the present invention to provide a glass molding press machine that a fixing hole which a lens holder is fixed to during a press working is formed in an intermediate die disposed between an upper die and a lower die, at a location corresponding to a potion that the upper core and the lower core contact.

It is another object of the present invention to provide a glass molding press machine which has at least upper core and lower core and a fixing hole of an intermediate die and can manufacture at least one coupling lens.

The present invention provides a glass molding press machine for manufacturing a coupling lens which includes a lens which transmits light and a lens holder made of a metal which accommodates and fixes the lens, comprising: an upper die including an upper holder and a plurality of upper cores; a lower die including a lower holder and a plurality of lower cores; an intermediate die which is disposed between the upper die and the lower die and has fixing holes which are formed at locations corresponding to the plurality of upper cores and the plurality of lower cores, wherein the lens holder is inserted into and fixed to the fixing hole during a press working; an intermediate die guide pin which couples the intermediate die to the upper die and the lower die; and an up-down driving unit which drives the upper die up or down relative to the lower die.

Preferably, the intermediate die has either of a structure for resistance welding by a laser stem and a structure for laser-welding to an optical transceiver housing.

Preferably, the lower holder of the lower die has a groove portion for protection of a protruding portion at a predetermined location that a protruding portion of the lens holder contacts in order to protect a protruding portion formed in a lower portion of the lens holder.

Preferably, the glass molding press machine further comprises a moving plate which is installed below the lower die and functions to keep a dimension of the machine and protect the machine when the glass molding press machine is moved for a plurality of processes.

Preferably, a bottom surface of the lens holder inserted into and fixed to the intermediate die contacts a top surface of the lower die.

Preferably, the coupling lens manufactured by the glass molding press machine includes a lens holder which has one side of a cylindrical shape made of a metal material and a fixing portion which is formed to protrude inwardly along an inner circumferential surface so that a central portion is inclined from both sides; and an aspheric glass lens which has a groove portion which is collapsed inwardly along an outer circumferential surface to be coupled and fixed to the fixing portion of the lens holder.

Preferably, the aspheric glass lens is an axis-symmetric aspheric glass lens that an aspheric form portion is formed non-axially from an optical axis in a perpendicular direction to an optical axis (Z-axis).

Preferably, the lens holder further includes a protruding portion which is formed to protrude along a circumferential direction at an end portion of one side.

Preferably, the fixing portion has a cross section of a triangular shape.

Preferably, the fixing portion has a cross section of a trapezoid shape.

The glass molding press machine according to the present invention has the following advantages.

At least one fixing hole is formed in the intermediate die disposed between the upper die and the lower die, and at least one lens holder is inserted into and fixed to the fixing hole. At least one coupling lens can be manufactured by a press working of one time, thereby reducing a manufacturing time of the coupling lens and improving manufacturing efficiency and productivity.

A bottom surface of the lens holder inserted into the fixing hole of the intermediate die contacts a top surface of the lower holder, and so even though a plurality of coupling lenses are manufactured, the coupling lenses are manufactured in a state that distances between lenses inside the lens holder are equal. This improves the quality of the coupling lens and reduces a percent defective of the coupling lens, leading to high reliability of a product.

Also, if a norm of the coupling lens gets deformed due to long time working or the coupling lens of a different norm needs to be manufactured, the intermediate die is replaced without installing another glass molding press machine, whereby the manufacturing cost is reduced, and the factory area can be effectively used.

The coupling lens manufactured according to the present invention can be applied to an asymmetric aspheric glass lens that one axis has an asymmetric shape, and can improve optical coupling efficiency even though the rate of a slow axis and a fast axis of a laser diode is increased and can focus a standardized beam to a photo diode and a fiber.

Moreover, the asymmetric aspheric glass lens is accurately coupled to and fixed to a protruding portion of a fixing portion. Accordingly, the installation accuracy is improved, and a phenomenon that the fixing portion and the asymmetric aspheric glass lens are separated is prevented, so that an optical characteristic of high accuracy is secured, and durability is improved, thereby improving mechanical reliability of a product.

The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail preferred embodiments thereof with reference to the attached drawings in which:

FIGs. 1A and 1B cross-sectional views illustrating a conventional glass molding press machine for manufacturing a coupling lens;

2A and 2B are views illustrating a conventional axis-symmetric aspheric glass lens;

FIGs. 3A to 3B are views illustrating am axis-asymmetric aspheric glass lens according to the exemplary embodiment of the present invention;

FIG. 4 is a graph illustrating coupling efficiency and curvature with respect to a divergence angle ratio of a laser beam in an optical coupling lens system;

FIG. 5 shows a coupling lens for an optical communication module which is manufactured by a glass molding press machine according to an exemplary embodiment of the present invention;

FIGs. 6A and 6B are cross-sectional views illustrating the coupling lens for the optical communication module which is manufactured by the glass molding press machine according to the exemplary embodiment of the present invention;

FIG. 7 is a cross-sectional view illustrating a modification of the coupling lens for the optical communication module which is manufactured by the glass molding press machine according to the exemplary embodiment of the present invention;

FIG. 8 shows one example of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention;

FIG. 9 shows another example of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention;

FIGs. 10A and 10B show an intermediate die of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention;

FIGs. 11A and 11B show another embodiment of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention;

FIG. 12 shows another embodiment of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention; and

FIG. 13 is a flowchart illustrating a manufacturing procedure of the glass molding press machine according to the exemplary embodiment of the present invention.

* Description of Major Symbol in the above Figures

1　:　press machine

2　:　conventional press machine

3　:　lens　　　　　　　　　　　　　　　　　　　　　　

4　:　lens holder

10　:　upper die　

20 :　　intermediate die　

30　:　lower die 　　　　　　　　　　　

40　:　moving plate

100 :　upper holder

110 :　upper core　　　　　　　　　

200 :　intermediate die guide pin

210 :　fixing hole

300 :　lower holder

310 :　upper core　　　　　　　　　　　　　　

320 :　groove portion

500 :　laser diode　　　　　

600 :　fixing portion

610 :　protruding portion　　　　　　　　

700 :　grooving portion

Hereinafter, an exemplary embodiment of the present invention will be described. However, the present invention is not limited to the exemplary embodiment of the present invention described below and can be embodied in various forms without departing from the spirit of essential characteristics thereof.

Coupling Lens

A coupling lens is a sort of an optical device which connects an optical cable and a photo diode to perform an optical transceiving operation such as optical connection and transmission and that a lens is formed integrally with a metal housing (hereinafter, lens holder) including a cylindrical metal case that an incident terminal has a cylindrical shape. The lens is commonly made of a glass-based material in order to secure reliability against heat generated in a laser, and an aspheric glass lens that a focus resolution is improved by minimizing a spherical aberration by an aspheric equation is preferably used as the lens. At this time, the aspheric glass lens has an axis-asymmetric or axis-symmetric aspheric shape, and in the exemplary embodiment of the present invention, the aspheric glass lens preferably has an axis-asymmetric aspheric shape.

An axis-asymmetric aspheric glass lens according to the exemplary embodiment of the present invention will be described in detail with reference to FIGs. 2 to 4.

FIGs. 2A and 2B are views illustrating a conventional axis-symmetric aspheric glass lens, and FIGs. 3A to 3B are views illustrating am axis-asymmetric aspheric glass lens according to the exemplary embodiment of the present invention. FIG. 4 is a graph illustrating coupling efficiency and curvature with respect to a divergence angle ratio of a laser beam in an optical coupling lens system.

An optical communication module transmits or receives a laser beam emitted from a laser diode 500 which is a light source using a glass focus lens or a glass collimator lens.

At this time, as shown in FIG. 2A, a laser beam emitted from the laser diode 500 is emitted in a slow axis (Y axis) direction and a fast axis (X axis) direction and has an elliptical shape according to a radiation ratio of each axis. If the elliptical beam is focused onto a fiber, as shown in FIG. 2B, optical efficiency is reduced.

When a glass lens 3′ having an axis-symmetric aspheric shape collimates and couples light having astigmatism of a laser diode, if a ratio of a slow axis and a fast axis of a laser diode is large, optical coupling efficiency is greatly reduced.

Commonly, optical transmission efficiency is more increased as {(θY/θX) ×100} is closer to 100 because (overlap integral in X direction)×(Overlap integral in Y direction) = coupling efficiency, but it is very difficult to make θX and θY identical to each other in manufacturing a laser chip.

For this reason, in the exemplary embodiment of the present invention, an axis-asymmetric aspheric glass lens 3 is used to improve optical transmission efficiency and improve transmittance by applying anti-reflection coating to both sides of a lens and coupling efficiency.

In detail, as shown in FIG. 3A, in the conventional axis-symmetric aspheric glass lens 3′, efficiency is lowered due to light diffusion when a beam that θX and θY are different is emitted from the laser diode 500, passes through a lens and is focused onto a fiber.

However, in an axis-asymmetric aspheric glass lens 3 according to the exemplary embodiment of the present invention, as shown in FIG. 3B, even though a beam that θX and θY are different passes through a lens and is focused onto a fiber, since an incident side of a lens which receives a laser beam is inclined, light is refracted, so that light diffusion is prevented, thereby improving optical transmission efficiency.

If the axis-asymmetric aspheric glass lens 3 is applied to an optical communication module, the axis-asymmetric aspheric glass lens 3 can be mounted opposite to the laser diode 500. In order to focus a beam standardized in the axis-asymmetric aspheric glass lens 3 onto a photo diode or a fiber, the conventional axis-symmetric aspheric glass lens can be used to condense and transmit or receive light. In this instance, connection efficiency can be improved.

The axis-asymmetric aspheric glass lens 3 can be employed in a structure which standardizes and focuses a laser beam as well as a general optical communication module.

The graph of FIG. 4 shows coupling efficiency and curvature with respect to a divergence angle ratio of a laser beam in an optical coupling lens system. In FIG. 4, a reference numeral 501 denotes a coupling efficiency curve of the axis-asymmetric aspheric glass lens, and a reference numeral 502 denotes a coupling efficiency curve of the conventional axis-symmetric aspheric glass lens. Also, in the graph of FIG. 4, a horizontal axis denote a divergence angle ratio {(θY/θX)100} of a θbeam of a light emitting device, and a vertical axis denotes coupling efficiency and a curvature 503 of an axis-asymmetric optical surface.

If the coupling efficiency curve 501 of the axis-asymmetric aspheric glass lens 3 is used, when a ratio of light divergence angles θX and θY is 2:1, the best efficiency is shown, and a efficiency limit is 10:1.5, whereas if the conventional axis-symmetric aspheric glass lens 3´ is used, in case of 2:1, the worst efficiency is shown, and it reaches a limit.

For example, Table 1 is an experimental table measured when a wavelength of light emitted from a light emitting device is 1550nm to compare the axis-asymmetric aspheric glass lens 3 with the axis-symmetric aspheric glass lens 3′.

Table 1

classification	Y Radius	X Radius	Thickness	Glass
Axis-asymmetric aspheric glass lens	Infinity		503 of graph	1.0	LBAL35 glass
Axis-asymmetric aspheric glass lens	-0.9336	-0.9336	5.0		LBAL35 glass
Axis-symmetric aspheric glass lens	0.9336	0.9336	1.0	LBAL35 glass
Axis-symmetric aspheric glass lens	Infinity	Infinity	1.0	LBAL35 glass

Here, the graph and the coupling efficiency of FIG. 4 and Table 1 are an experimental example to describe the axis-asymmetric aspheric glass lens according to the exemplary embodiment of the present invention, and the present invention is not limited to the graph and Table described above.

It is because in the experimental example described above, as shown in FIGs. 3A and 3B, a beam emitted from the laser beam source is standardized and collimated by the axis-asymmetric aspheric glass lens and is then coupled to an optical fiber by the typical axis-symmetric aspheric glass lens.

Meanwhile, a lens holder 4 of the coupling lens functions to accommodate and fixe the axis-asymmetric aspheric glass lens 3. In order to manufacture the lens holder 4 having a receptacle structure with a weldable structure, preferably, the lens holder is formed to protrude in an inside diameter direction thereof. The lens holder 4 according to the exemplary embodiment of the present invention will be described in detail with reference to FIGs. 5 to 7.

FIG. 5 shows a coupling lens for an optical communication module which is manufactured by the glass molding press machine according to the exemplary embodiment of the present invention. FIGs. 6A and 6B are cross-sectional views illustrating the coupling lens for the optical communication module which is manufactured by the glass molding press machine according to the exemplary embodiment of the present invention. FIG. 7 is a cross-sectional view illustrating a modification of the coupling lens for the optical communication module which is manufactured by the glass molding press machine according to the exemplary embodiment of the present invention.

The lens holder 4 has a cylindrical shape and is preferably made of ferrite stainless steel which is more excellent in corrosion resistance and heat resistance than austenite stainless steel or aluminum.

In detail, a material of the lens holder 4 is ferrite stainless steel and DHS1, and is excellent in outgas characteristic than SF2OT. Outgas is a phenomenon that a component adhered to a material surface is seceded into a process gas or a component accumulated in a material is emitted and is a factor which hurts supply of ultrapure gas when molding a glass lens. In order to remove outgas, an actual surface area should be minimized by improving surface toughness, and therefore it requires very precise processing.

However, DHS1 is excellent in outgas characteristic and so is excellent in processing efficiency for precise processing, and has a characteristic that high temperature molding corrosion resistance at a nitrogen atmosphere and surface cleaning property of a finished product are excellent.

The lens holder 4 which has a cylindrical shape having a predetermined inside diameter is formed such that an incident terminal has a cylindrical shape, a laser stem (not shown) is coupled to the cylinder space inside and is formed to protrude inwardly in an inside diameter direction.

In detail, the lens holder 4 includes a fixing portion 600 that is formed to protrude inwardly such that the width gets narrower as it gets farther from the inner circumferential surface as shown in a cross-sectional view of FIG. 5 taken along line A-A´. That is, the fixing portion 600 is formed such that its central portion is inclined from both ends which contact the inner circumferential surface of the lens holder 4. Preferably, the fixing portion 600 has a cross section of a triangular shape.

The axis-asymmetric aspheric glass lens 3 is coupled to and fixed to the fixing portion 600, and the fixing portion 600 protects the axis-asymmetric aspheric glass lens 3. The fixing portion 600 is formed to protrude in an inside diameter direction of the lens holder 4, and thus it becomes easier to process the lens holder 4 which is a cylindrical metal case, and coupling force of the axis-asymmetric aspheric glass lens 3 is increased.

That is, as shown in FIG. 5, the lens holder 4 has a structure that the inside diameter gets smaller as it is closer to a central portion from both ends. Therefore, the lens holder 4 is not processed inside the lens holder 4, and a shape of the lens holder 4 can be externally easily processed using a cutting tool. Accordingly, a processing time is reduced, and processability is improved.

Meanwhile, the axis-asymmetric aspheric glass lens 3 has a groove portion 700 to which the fixing portion 600 of the lens holder 4 is coupled and fixed as shown in FIGs. 6A and 6B. That is, the groove portion 700 which is collapsed inwardly along the outer circumferential surface is formed in the axis-asymmetric aspheric glass lens 3 to be coupled to the fixing portion 600 which is formed to protrude.

The groove portion 700 formed along the outer circumferential surface of the axis-asymmetric aspheric glass lens 3 is coupled with the fixing portion 600 of the lens holder 4, so that the axis-asymmetric aspheric glass lens 3 is accurately fixed to the lens holder 4.

Also, since the axis-asymmetric aspheric glass lens 3 is filled at a location adjacent to the fixing portion 600, a filled area becomes firm, and so the lens holder 4 made of a metal material and the axis-asymmetric aspheric glass lens 3 can be firmly integrated.

As a result, a phenomenon that the lens holder 4 and the axis-asymmetric aspheric glass lens 3 are separated or seceded from each other is prevented, an optical characteristic of high accuracy is secured, and durability is improved, whereby mechanical reliability of a product is improved.

Further, in the lens holder 4, even though a material is pressed by the fixing portion 600 which is formed to protrude, since the fixing portion 600 is formed to be inclined, the material is pushed out toward both sides of the fixing portion 600, and so an over flow area of the material can be secured.

Therefore, a phenomenon that the axis-asymmetric aspheric glass lens 3 is separated in the lens holder can be prevented, so that the installation accuracy can be more improved, and a lens performance can be satisfied with respect to randomicity of a material used, whereby a performance of a product can be more improved.

Furthermore, since a portion of the axis-asymmetric aspheric glass lens 3 that light transmits is locally restricted to a central portion, the fixing portion 600 of the lens holder 4 can be expanded or modified, and the groove portion 700 of the axis-asymmetric aspheric glass lens 3 can be performed with a corresponding structure to the fixing portion 600.

Therefore, the size of the axis-asymmetric aspheric glass lens 3 can be minimized.

Therefore, since the size of the axis-asymmetric aspheric glass lens 3 can be minimized, the product price can be reduced. That is, as the size of the axis-asymmetric aspheric glass lens 3 can be minimized, a use of a high cost material can be reduced, and so the price of the coupling lens including the axis-asymmetric aspheric glass lens 3 can be reduced.

FIG. 6B shows a protruding portion according to the exemplary embodiment of the present invention, and the protruding portion can be employed in a structure that a laser stem is resistance-welded and coupled to an incident end side of the lens holder 4 having the cylindrical shape.

In detail, the lens holder 4 further includes a protruding portion 610 which is formed at an end portion of its one side to protrude along a circumferential direction.

One side of the lens holder 4 has a cylindrical shape, and the laser stem including a laser diode is coupled thereto. At this time, due to the protruding portion 610, the laser stem can be easily resistance-welded and coupled, thereby improving reliability of sealing force after welding.

FIG. 7 is a cross-sectional view illustrating a modification of the coupling lens for the optical communication module according to the exemplary embodiment of the present invention. The fixing portion 600 of the lens holder 4 for fixing the axis-asymmetric aspheric glass lens 3 has a cross section of a trapezoid shape as shown in FIG. 7.

As described above, the cross section of the fixing portion 600 of the lens holder 4 is not limited to a triangular shape and can include various protruding shapes such as a trapezoid shape. In this instance, the groove portion 700 of the axis-asymmetric aspheric glass lens 3 can has a shape corresponding to the protruding shape of the fixing portion 600.

Glass Molding Press Machine for Manufacturing the Coupling Lens

A glass molding press machine for manufacturing the coupling lens according to the exemplary embodiment of the present invention will be described below in detail.

FIG. 8 shows one example of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention, and FIG. 9 shows another example of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention.

The glass molding press machine 1 of the present invention includes an upper die 10, a lower die 30 and an up-down driving unit which drives the upper and lower dies 10 and 30 up or down. Also, an intermediate die 20 is disposed between the upper die 10 and the lower die 30, and an intermediate die guide pin 200 is disposed to connect the intermediate die 20 and the lower die 30.

The upper die 10, the intermediate die 20 and the lower die 30 constitutes a basic frame of the glass molding press machine 1 of the present invention. The upper die 10 goes up or down by the up-down driving unit with respect to the lower die 30. The up-down driving unit is divided into an oil pressure type and a mechanical type according to a structure which generates compressive force.

A press working is performed in a state that an upper holder 100 and an upper core 110 are mounted in the upper die 10 and a lower holder 300 and a lower core 310 are mounted in the lower die 30. In the exemplary embodiment of the present invention, at least one upper core 110 and at least one lower core 310 are disposed, and thus a plurality of coupling lenses can be manufactured by a press working of one time. At this time, the intermediate die 20 is disposed between the upper die 10 and the lower die 30 and is coupled to the upper die 10 and the lower die 30. At this time, the intermediate die 10 is coupled to a lower portion of the upper die 10 and an upper portion of the lower die 20 using the intermediate guide pin 320.

The intermediate die 20 coupled to the upper die 10 and the lower die 30 has a fixing hole 210 which is formed at a location corresponding to the upper core 110 of the upper die 10 and the lower core 310 of the lower die 30. The fixing hole 210 functions to fix the lens holder 4 when the lens holder 4 is inserted thereinto. Ball glass similar to a lens volume is inserted into the inside diameter of the lens holder 4 inserted into and fixed to the fixing hole 210 of the intermediate die 20, and then a press working is performed to mold the ball glass into a lens 3, whereby the coupling lens coupled to the lens holder 4 is manufactured. A procedure for manufacturing the coupling lens by the glass molding press machine according to the exemplary embodiment of the present invention will be described later in detail with reference to FIG. 13.

A moving plate 40 is coupled to the lower portion of the lower die and functions to keep a dimension of the die and to protect the die when the lower die of the glass molding pres machine is moved for each process.

FIGs. 10A and 10B show the intermediate die of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention. The intermediate die 20 of the glass molding press machine 1 can be replaced and used according to a kind of the coupling lens to be press-processed. For example, as shown in FIGs. 10A and 10B, a structure of the intermediate die 20 can be different according to the coupling lens to be press-processed. FIG. 10A shows a structure of the intermediate die 20 for resistance-welding by a laser stem, and FIG. 10B shows a structure of the intermediate die 20 for laser-welding to an optical transceiving housing. The intermediate dies 20 having different structures can be used in one glass molding press machine by replacement, thereby reducing the cost and saving a space of, for example, a factory.

Meanwhile, if the intermediate die 20 has a structure for resistance-welding by the laser stem as shown in FIG. 10A, a protruding portion is formed in the lower portion of the lens holder 4 for resistance-welding. The protruding portion has to maintain a precise processing state, and so a groove portion 320 for protection of the protruding portion is preferably formed at a predetermined location of the lower holder 300 which contacts the lens protruding portion to protect the protruding portion 610.

FIGs. 11A and 11B show another embodiment of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention. The glass molding press machine of FIG. 11 includes an upper die 10 including a plurality of upper cores 110, a lower die 30 including a plurality of lower cores 310, and an intermediate die 20 disposed between the upper die 10 and the lower die 30.

In FIGs. 8 to 10 and FIG. 11, like reference numerals denote like parts, and thus the duplicated description on like parts will not be repeated. As shown in FIGs. 11A and 11B, a plurality of upper cores 110 and a plurality of lower cores 310 are disposed. The intermediate die 20 has a plurality of fixing holes 210 which are formed at locations corresponding to a plurality of upper cores 110 and a plurality of lower cores 310. Therefore, a plurality of coupling lenses can be manufactured by the press working of one time.

Also, FIG. 12 shows another embodiment of the glass molding press machine for manufacturing a plurality of coupling lenses according to the exemplary embodiment of the present invention.

As shown in the drawing, in the present embodiment, the press machine 1 can be used to manufacture a general aspheric glass lens such as a coupling lens (bare type aspheric coupling lens, hereinafter bare type lens ) which comprises only a lens without a lens holder and a camera lens.

As described above, the intermediate die 20 of the glass molding press machine 1 according to the present invention can be replaced according to a kind of a coupling lens to be press-processed, and thus there is an advantage that a plurality of bare type lenses which do not have a lens holder as well as a plurality of coupling lenses which have a lens holder can be manufactured.

Process for Manufacturing the Coupling Lens

FIG. 13 is a flowchart illustrating a manufacturing procedure of the glass molding press machine according to the exemplary embodiment of the present invention. As shown in FIG. 13, the lower holder 300 and the lower core 310 that an aspheric shape is processed are assembled to form the lower die 30. The lower die 30 is fixed to the moving plate 40. The moving plate 40 functions to keep a dimension of the machine and to protect the machine when the glass molding pres machine 1 is moved for each process, thereby preventing the glass molding press machine 1 from being damaged or deformed during the press working (step s10). Then, the intermediate die 20 is inserted and installed on the lower die 30. At this time, the intermediate die 20 is installed on the lower die 30 using the intermediate die guide pin 200 (step s20). The intermediate die 20 has at least one fixing hole 210 which the lens holder 4 is inserted into and fixed to.

The lens holder 40 is inserted into and fixed to the intermediate die 20, and ball glass similar to a lens volume is putted (step s30). Ball glass is a material of a glass lens and is melted at a high temperature to be transformed in a lens 3 form. If it is assumed that a volume of ball glass is A and a volume of a completed lens is B, a volume A of ball glass is preferably B * 0.975 to 0.999 because it can prevent a phenomenon that a lens is broken and increase a lifespan of each core of the glass molding press machine 1. All bottom surfaces of the lens holders 4 respectively inserted into and fixed to a plurality of fixing holes 210 contact a top surface of the lower die 30. When a plurality of coupling lenses are manufactured, the bottom surfaces of the lens holders 4 which are a mounting reference surface are installed on the top surface of the lower die 30 at the same height, and thus distances between the lenses in the lens holder 4 are equal, whereby an optical axis of the lens 3 can be more precisely manufactured. Accordingly, the percent defective of the coupling lens can be significantly reduced.

The upper die 10 including the upper core 110 and the upper holder 100 is coupled to the lower die 20 coupled to the intermediate die 30 by the intermediate die guide pin 200 and a lower die guide pin (step s40). Thereafter, the press working is performed, and the lens height randomly set by a user is adjusted by pressing the upper core 110. A metal ring is preferably used to adjust the lens height to the press height of the glass molding press machine. The metal ring is coupled to the external diameter of the glass molding press machine. Ball glass is preferably heated at the temperature of 105 to 115% of a glass yield point (At). Ball glass is gradually molded into a lens form by pressing the upper core 110 which protrude from the upper die 10 by the protruding length (step s50). At this time, in order to prevent the lens holder 4 from being oxidized, the inside of the glass molding press machine preferably maintains a nitrogen atmosphere. After finishing the press working of the coupling lens, the inside of the glass molding press machine is cooled down to an opening temperature, and then a plurality of coupling lenses are extracted (step s60).

Claims

A glass molding press machine for manufacturing a coupling lens which includes a lens which transmits light and a lens holder made of a metal which accommodates and fixes the lens, comprising:

an upper die including an upper holder and a plurality of upper cores;

a lower die including a lower holder and a plurality of lower cores;

an intermediate die which is disposed between the upper die and the lower die and has fixing holes which are formed at locations corresponding to the plurality of upper cores and the plurality of lower cores, wherein the lens holder is inserted into and fixed to the fixing hole during a press working;

an intermediate die guide pin which couples the intermediate die to the upper die and the lower die; and

an up-down driving unit which drives the upper die up or down relative to the lower die.
The glass molding press machine of claim 1, wherein the intermediate die has either of a structure for resistance welding by a laser stem and a structure for laser-welding to an optical transceiver housing.
The glass molding press machine of claim 1, wherein the lower holder of the lower die has a groove portion for protection of a protruding portion at a predetermined location that a protruding portion of the lens holder contacts in order to protect a protruding portion formed in a lower portion of the lens holder.
The glass molding press machine of claim 1, further comprising, a moving plate which is installed below the lower die and functions to keep a dimension of the machine and protect the machine when the glass molding press machine is moved for a plurality of processes.
The glass molding press machine of claim 1, wherein a bottom surface of the lens holder inserted into and fixed to the intermediate die contacts a top surface of the lower die.
The glass molding press machine of claim 1, wherein the coupling lens manufactured by the glass molding press machine includes

a lens holder which has one side of a cylindrical shape made of a metal material, a fixing portion which is formed to protrude inwardly along an inner circumferential surface so that a central portion is inclined from both sides and a protruding portion which is formed to protrude along a circumferential direction at an end portion of the one side; and

an aspheric glass lens which has a groove portion which is collapsed inwardly along an outer circumferential surface to be coupled and fixed to the fixing portion of the lens holder.
The glass molding press machine of claim 6, wherein the aspheric glass lens is an axis-symmetric aspheric glass lens that an aspheric form portion is formed non-axially from an optical axis in a perpendicular direction to an optical axis (Z-axis).