U.S. patent application number 10/140282 was filed with the patent office on 2002-09-19 for method of manufacturing optical lens.
This patent application is currently assigned to HAMAMATSU PHOTONICS K.K.. Invention is credited to Kusuyama, Yutaka.
Application Number | 20020129621 10/140282 |
Document ID | / |
Family ID | 18114898 |
Filed Date | 2002-09-19 |
United States Patent
Application |
20020129621 |
Kind Code |
A1 |
Kusuyama, Yutaka |
September 19, 2002 |
Method of manufacturing optical lens
Abstract
An optical lens manufacturing method according to the present
invention is characterized by including the first optical member
preform forming step of forming a first optical member preform 40
formed of a first transparent material into a columnar shape and
having a first optical acting portion 11 that forms a curved
surface on a side surface thereof, the primary drawing step of
drawing the first optical member preform formed by the first
optical member preform forming step, and the first optical member
forming step of slicing the first optical member preform drawn 40
in the primary drawing step, thus forming a first optical member 2
with a columnar shape. According to this optical lens manufacturing
method, the shape of the optical lens, and particularly the shape
of the first optical acting portion 11, can be determined at the
stage of the preform before primary drawing. Thus, the preform can
be machined with a sufficiently large size, and machining
operations can be performed simply and accurately.
Inventors: |
Kusuyama, Yutaka;
(Hamamatsu-shi, JP) |
Correspondence
Address: |
MORGAN LEWIS & BOCKIUS LLP
1111 PENNSYLVANIA AVENUE NW
WASHINGTON
DC
20004
US
|
Assignee: |
HAMAMATSU PHOTONICS K.K.
|
Family ID: |
18114898 |
Appl. No.: |
10/140282 |
Filed: |
May 8, 2002 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10140282 |
May 8, 2002 |
|
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PCT/JP00/07955 |
Nov 10, 2000 |
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Current U.S.
Class: |
65/61 ;
65/64 |
Current CPC
Class: |
C03B 23/047 20130101;
G02B 3/0012 20130101; G02B 3/0056 20130101; C03B 37/025 20130101;
B29D 11/00009 20130101; G02B 3/06 20130101; G02B 3/005
20130101 |
Class at
Publication: |
65/61 ;
65/64 |
International
Class: |
C03C 019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 10, 1999 |
JP |
P1999-319847 |
Claims
What is claimed is:
1. An optical lens manufacturing method characterized by
comprising: the first optical member preform forming step of
forming a first optical member preform formed of a first
transparent material into a columnar shape and having a first
optical acting portion that forms a curved surface on a side
surface thereof; the first drawing step of drawing the first
optical member preform formed in the first optical member preform
forming step; the first optical member forming step of slicing the
first optical member preform drawn in the first drawing step, thus
forming a first optical member with a columnar shape; the optical
lens preform forming step of forming an optical lens preform formed
such that a first optical member array, formed by arraying a
predetermined number of first optical members fabricated in the
first optical member forming step in one or two rows is surrounded
by a second optical member made of a second transparent material;
the secondary drawing step of drawing the optical lens preform
fabricated in the optical member preform forming step; the optical
lens form forming step of slicing)the optical lens preform drawn in
the secondary drawing step, thereby forming an optical lens form;
and the optical lens form machining step of cutting the optical
lens form fabricated in the optical lens form forming step, thereby
forming an optical lens with a desired shape.
2. An optical lens manufacturing method according to claim 1,
wherein the second optical member has a cylindrical tube and a
plurality of spacers arranged to fill a gap between the cylindrical
tube and one or two rows of the first optical member arrays
inserted at a center in the cylindrical tube.
3. An optical lens manufacturing method according to claim 1,
wherein the first transparent material has a thermal expansion
coefficient which is higher than that of the second transparent
material.
4. An optical lens manufacturing method according to claim 1,
wherein the first transparent material has a refractive index which
is different from that of the second transparent material.
5. An optical lens manufacturing method according to claim 1,
wherein the first transparent material has a yielding point which
is higher than a temperature necessary for the secondary drawing
step, and the second transparent material has a yielding point
which is lower than a temperature necessary for the secondary
drawing step.
6. An optical lens manufacturing method according to claim 1,
wherein when the optical lens preform is to be sliced in the
optical lens form forming step, the optical lens preform is sliced
while inclined with respect to a drawing direction.
7. An optical lens manufacturing method according to claim 1,
wherein the first optical member preform has a semicircular
cylindrical shape.
8. An optical lens manufacturing method according to claim 1,
wherein the first optical member preform has a cylindrical
shape.
9. An optical lens manufacturing method according to claim 1,
wherein the first transparent material has a refractive index which
is different from that of the second transparent material.
10. An optical lens manufacturing method according to claims 1,
wherein the optical lens form machining step includes machining
such that either one of respective side surfaces of the first
optical member array which does not have a first optical acting
portion is exposed.
11. An optical lens manufacturing method according to claim 1,
wherein the optical lens form machining step includes the second
optical acting portion forming step of forming a second optical
acting portion by polishing the second optical member.
12. An optical lens manufacturing method according to claims 1,
wherein the optical lens form machining step includes the second
optical acting portion forming step of forming a second optical
acting portion by adhering an optical member made of the second
transparent material to the second optical member.
13. An optical lens manufacturing method characterized by
comprising: the first optical member preform forming step of
forming a first optical member preform formed of a first
transparent material into a columnar shape and having a first
optical acting portion that forms a curved surface on a side
surface thereof; the first drawing step of drawing the first
optical member preform formed in the first optical member preform
forming step; the first optical member forming step of slicing the
first optical member preform drawn in the first drawing step, thus
forming a first optical member with a columnar shape; the optical
lens preform forming step of forming an optical lens preform formed
such that the first optical member array, formed by arraying a
predetermined number of first optical members fabricated in the
first optical member forming step in one or two rows is surrounded
by a second optical member made of a second transparent material;
the heating/compressing step of heating and compressing the optical
lens preform fabricated in the optical lens preform forming step;
the optical lens form forming step of slicing the optical lens
preform heated and compressed in the heating/compressing step,
thereby forming an optical lens form; and the optical lens form
machining step of cutting the optical lens form fabricated in the
optical lens form forming step, thereby forming an optical lens
with a desired shape.
14. An optical lens manufacturing method according to claim 13,
wherein the first transparent material has a yielding point which
is higher than a temperature necessary for the heating/compressing
step, and the second transparent material has a yielding point
which is lower than a temperature necessary for the
heating/compressing step.
15. An optical lens manufacturing method according to claim 13,
wherein the first optical member preform has a semicircular
cylindrical shape.
16. An optical lens manufacturing method according to claim 13,
wherein the first optical member preform has a cylindrical
shape.
17. An optical lens manufacturing method according to claim 13,
wherein the first transparent material has a refractive index which
is different from that of the second transparent material.
18. An optical lens manufacturing method according to claim 13,
wherein the optical lens form machining step includes machining
such that either one of respective side surfaces of the first
optical member array which does not have a first optical acting
portion is exposed.
19. An optical lens manufacturing method according to claim 13,
wherein the optical lens form machining step includes the second
optical acting portion forming step of forming a second optical
acting portion by polishing the second optical member.
20. An optical lens manufacturing method according to claim 13,
wherein the optical lens form machining step includes the second
optical acting portion forming step of forming a second optical
acting portion by adhering an optical member made of the second
transparent material to the second optical member.
21. An optical member manufacturing method comprising: the first
optical member preform forming step of forming a first optical
member preform formed of a first transparent material into a
columnar shape and having a side surface including a plurality of
curved surface portions formed parallel to the column axis and
arranged in contact with each other; the first drawing step of
drawing the first optical member preform formed in the first
optical member preform forming step; and the first optical member
forming step of slicing the first optical member preform drawn in
the first drawing step, thus forming a first optical member with a
columnar shape.
22. An optical lens manufacturing method comprising: the optical
lens preform forming step of forming an optical lens preform formed
such that the first optical member formed in the optical member
manufacturing method according to claim 21 is surrounded by a
second optical member made of a second transparent material; the
secondary drawing step of drawing the optical lens preform
fabricated in the optical lens preform forming step; the optical
lens form forming step of slicing the optical lens preform drawn in
the secondary drawing step, thereby forming an optical lens form;
and the optical lens form machining step of cutting the optical
lens form fabricated in the optical lens form forming step, thereby
forming an optical lens with a desired shape.
Description
RELATED APPLICATIONS
[0001] This is a Continuation-In-Part application of International
Patent application serial No. PCT/JP00/07955 filed on Nov. 10,
2000, now pending.
BACK GROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method of manufacturing
an optical lens that acts on a light beam emitted from a
light-emitting device and, more particularly, to a method of
manufacturing an optical lens that acts on light beams emitted from
a light-emitting device in which a plurality of light-emitting
portions are arrayed.
[0004] 2. Related Background Art
[0005] In the manufacture of an optical lens for a semiconductor
laser array in which a plurality of light-emitting portions are
arrayed, conventionally, the manufacture with a precision mold or
manufacture by applying a silicon semiconductor manufacturing
process or LIGA process has been performed.
SUMMARY OF THE INVENTION
[0006] In the conventional optical lens manufacturing method, the
size itself of the required optical lens is very small, and
accordingly it is very difficult to form an optical acting portion
that collimates or condenses light beams emitted from the
light-emitting portions of the semiconductor laser array.
[0007] It is, therefore, an object of the present invention to
provide an optical lens manufacturing a method which can form an
optical acting portion easily.
[0008] In order to achieve the above object, an optical lens
manufacturing method according to the present invention is
characterized by comprising the first optical member preform
forming step of forming a first optical member preform formed of a
first transparent material into a columnar shape and having a first
optical acting portion that forms a curved surface on a side
surface thereof, the primary drawing step of drawing the first
optical member preform formed in the first optical member preform
forming step, and the first optical member forming step of slicing
the first optical member preform drawn in the primary drawing step,
thus forming a first optical member with a columnar shape.
[0009] According to this optical lens manufacturing method, the
shape of the optical lens, and particularly the shape of the first
optical acting portion, can be determined at the stage of the
preform before primary drawing. Thus, the preform can be machined
with a sufficiently large size. Note that the "optical acting
portion" refers to a portion that can emit an incident divergent
light beam after reducing its divergent angle. The "first optical
member" is included in the optical lens. Concerning a term with a
prefix "first", the portion corresponding to the "first" may be
omitted if consideration is made with only the contents described
above.
[0010] The optical lens manufacturing method may comprise the
optical lens preform forming step of forming an optical lens
preform formed such that a first optical member array formed by
arraying a predetermined number of first optical members fabricated
in the first optical member forming step in one or two rows is
surrounded by a second optical member made of a second transparent
material, the secondary drawing step of drawing the optical lens
preform fabricated in the optical member preform forming step, the
optical lens form forming step of slicing the optical lens preform
drawn in the secondary drawing step, thereby forming an optical
lens form, and the optical lens form machining step of cutting the
optical lens form fabricated in the optical lens form forming step,
thereby forming an optical lens with a desired shape.
[0011] According to this optical lens manufacturing method, an
optical lens in which one optical member is buried in the other
optical member is fabricated. The first optical member array can be
arranged to be surrounded by the second optical member at the stage
of the preform before the secondary drawing step. Thus, the
arranging operations can be performed with a sufficiently large
size.
[0012] For example, the second optical member may have a
cylindrical tube and a plurality of spacers arranged to fill a gap
between the cylindrical tube and one or two rows of first optical
member arrays inserted at a center in the cylindrical tube. Since
the second optical member is divided into a plurality of portions,
it can be arranged more easily.
[0013] The first transparent material preferably has a thermal
expansion coefficient which is higher than that of the second
transparent material. When an optical lens is manufactured by
covering a material with a high thermal expansion coefficient with
a material with a low thermal expansion coefficient, a strong
structure which is not broken easily can be obtained due to a
caulking effect.
[0014] The first transparent material preferably has a refractive
index which is different from that of the second transparent
material. Then, the operation with the optical acting portion
functions effectively by utilizing a difference in refractive
index.
[0015] The first transparent material preferably has a yielding
point which is higher than a temperature necessary for the
secondary drawing step, and the second transparent material
preferably has a yielding point which is lower than a temperature
necessary for the secondary drawing step. Then, in the secondary
drawing step, while the first optical member made of the first
transparent material maintains its shape, the second optical member
made of the second transparent material is dissolved, and the
second transparent material fills the gap between the first and
second optical members.
[0016] When the optical lens preform is to be sliced in the optical
lens form forming step, it may be sliced while inclined with
respect to a drawing direction. Then, an optical lens in which
first optical members are arrayed to be inclined with respect to
the axial direction of the first optical member array can be
fabricated.
[0017] The optical lens manufacturing method may comprise the
optical lens preform forming step of forming an optical lens
preform formed such that the first optical member array formed by
arraying a predetermined number of first optical members fabricated
in the first optical member forming step in one or two rows is
surrounded by a second optical member, the heating/compressing step
of heating and compressing the optical lens preform fabricated in
the optical lens preform forming step, the optical lens form
forming step of slicing the optical lens preform heated and
compressed in the heating/compressing step, thereby forming an
optical lens form, and the optical lens form machining step of
cutting the optical lens form fabricated in the optical lens form
forming step, thereby forming an optical lens with a desired
shape.
[0018] According to this manufacturing method, an optical lens can
be fabricated by performing drawing operation once.
[0019] The first transparent material preferably has a yielding
point which is higher than a temperature necessary for the
heating/compressing step, and the second transparent material
preferably has a yielding point which is lower than a temperature
necessary for the heating/compressing step. Then, in the
heating/compressing step, while the first optical member made of
the first transparent material maintains its shape, the second
optical member made of the second transparent material is
dissolved, and the second transparent material fills the gap
between the first and second optical members.
[0020] The optical lens manufacturing method may comprise the
optical lens preform forming step of solidifying a first optical
member array, formed by arraying a predetermined number of first
optical members fabricated in the first optical member forming step
in one or two rows, with a light-transmitting resin from around,
thereby forming an optical lens preform, the optical lens form
forming step of slicing the optical lens preform fabricated in the
optical lens preform forming step, thereby forming an optical lens
form, and the optical lens form machining step of cutting the
optical lens form fabricated in the optical lens form forming step,
thereby forming an optical lens with a desired shape.
[0021] According to this manufacturing method, an optical lens can
be fabricated by performing drawing operation once. Also, since the
resin used for hardening transmits light, it serves as an optical
member.
[0022] The first optical member preform described above has, e.g.,
a semicircular cylindrical shape. Note that the "semicircular
cylindrical shape" refers to a columnar shape, as shown in FIG. 1A,
with one side surface (the bottom surface in FIG. 1A) that forms a
flat surface and the other side surface (the upper surface in FIG.
1A) that forms a convex curved surface. The curved surface may be
aspherical, and a pair of side surfaces 42 formed of flat surfaces
may be formed, as shown in FIG. 1A.
[0023] The first optical member preform described above may
alternatively have a cylindrical shape.
[0024] The first transparent material preferably has a refractive
index which is different from that of the second transparent
material. Then, the operation with the optical acting portion
functions effectively.
[0025] The optical lens form machining step may include machining
such that either one of respective side surfaces of the first
optical member array which does not have a first optical acting
portion is exposed. When a portion with no optical acting portion
is removed, the optical lens can be downsized.
[0026] The optical lens form machining step may include the second
optical acting portion forming step of forming a second optical
acting portion by polishing the second optical member.
Alternatively, the optical lens form machining step may include the
second optical acting portion forming step of forming a second
optical acting portion by adhering an optical member made of the
second transparent material to the second optical member. Then,
optical acting portions are formed on the first and second optical
members, respectively, so an optical lens that can optically act on
the incident light beams in various manners is realized.
[0027] An optical member manufacturing method according to the
present invention comprises the first optical member preform
forming step of forming a first optical member preform formed of a
first transparent material into a columnar shape and having a side
surface including a plurality of curved surface portions formed
parallel to the column axis and arranged in contact with each
other, the first drawing step of drawing the first optical member
preform formed in the first optical member preform forming step,
and the first optical member forming step of slicing the first
optical member preform drawn in the first drawing step, thus
forming a first optical member with a columnar shape.
[0028] An optical lens manufacturing method according to the
present invention comprises the optical lens preform forming step
of forming an optical lens preform formed such that the first
optical member formed in the optical member manufacturing method
according to the present invention is surrounded by a second
optical member made of a second transparent material, the secondary
drawing step of drawing the optical lens preform fabricated in the
optical lens preform forming step, the optical lens form forming
step of slicing the optical lens preform drawn in the secondary
drawing step, thereby forming an optical lens form, and the optical
lens form machining step of cutting the optical lens form
fabricated in the optical lens form forming step, thereby forming
an optical lens with a desired shape.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIGS. 1A to 1C are schematic views showing the steps in a
method of manufacturing an optical lens according to the first
embodiment;
[0030] FIGS. 2A to 2C are schematic views showing the steps in a
method of manufacturing an optical lens according to the first
embodiment which is an example different from that shown in FIG.
1;
[0031] FIGS. 3A to 3C are schematic views showing the steps in a
method of manufacturing an optical lens according to the first
embodiment which is an example different from those shown in FIGS.
1 and 2;
[0032] FIGS. 4A and 4B are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
first embodiment;
[0033] FIGS. 5A and 5B are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
first embodiment which is an example different from that shown in
FIG. 4;
[0034] FIGS. 6A and 6B are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
first embodiment which is an example different from those shown in
FIGS. 4 and 5;
[0035] FIGS. 7A to 7D are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
first embodiment;
[0036] FIGS. 8A and 8B are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
first embodiment which is an example different from that shown in
FIG. 7;
[0037] FIGS. 9A and 9B are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
first embodiment which is an example different from those shown in
FIGS. 7 and 8;
[0038] FIGS. 10A to 10D are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
second embodiment; and
[0039] FIGS. 11A to 11C are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
third embodiment.
DESCTIPRION OF THE PREFERRED EMBODIMENTS
[0040] The embodiments of the present invention will be described
in detail with reference to the accompanying drawings. In the
following description, the same or identical portions are denoted
by the same reference numerals, and a repetitive explanation will
be omitted.
[0041] FIGS. 1A to 1C are schematic views showing the steps in a
method of manufacturing an optical lens according to the first
embodiment. First, an optical material made of a first transparent
material (glass material) is prepared, and is molded into a
semicircular cylindrical shape with a bottom surface 41 and convex
curved surface 43, as shown in FIG. 1A, to form a first optical
member preform 40. The upper convex curved surface 43 is a portion
that forms a first optical acting portion 11 in a first optical
member 2 as an optical lens to be formed. In this manner, in an
optical lens manufacturing method employing drawing, the shape of
an optical lens to be fabricated, and particularly the shape of an
optical acting portion, can be formed at the stage of the first
optical member preform 40 with a sufficiently large size. Thus, the
operations of forming the shape of the optical lens and the shape
of the optical acting portion can be performed easily and
accurately. As shown in FIG. 1B, the molded first optical member
preform 40 is fused by heating in an electric furnace 35 or the
like and is subjected to primary drawing to obtain a desired
diameter. That portion which has been subjected to primary drawing
to reach the desired diameter is cut to form the first optical
member 2 (this will be called the "core 45" in the description from
FIG. 4). Because of the characteristics of the drawing process, the
first optical member 2 has the same sectional shape as that of the
first optical member preform 40. The first optical member 2
fabricated in this manner collimates an incident light beam 6 with
the first optical acting portion 11 formed on the light-incident
side and then emits an exit light beam 7.
[0042] FIGS. 2A to 2C and 3A to 3C show examples in which first
optical member preforms 40 have different shapes. As shown in FIG.
2A, the first optical member preform 40 may be formed into a
cylindrical shape. In this case, as shown in FIG. 2C, a first
optical member 2 to be manufactured has first optical acting
portions 11 on both the light-incident and light-exit sides. Each
first optical acting portion 11 collimates a divergent incident
light beam 6 and emits an emerging light beam 7. As shown in FIG.
3A, the first optical member preform 240 may be fabricated by a
plurality of first optical member preforms 40 with a semicircular
cylindrical shape shown in FIG. 1A, which are arrayed side by side
in tight contact with each other. The first optical preform 240
thus fabricated has a side surface including a plurality of curved
surface portions formed parallel to the column axis and arranged in
contact with each other. In this case, as shown in FIG. 3C, a first
optical member with a plurality of first optical acting portions 11
is formed. Thus, one first optical member can cope with a
semiconductor laser array serving as a light-emitting device in
which a plurality of light-emitting portions are arrayed.
[0043] FIGS. 4A and 4B are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
first embodiment. FIG. 4A shows the overall image of an optical
lens preform 50. First, cores 45 each formed as shown in FIG. 1B
are arrayed, with a second optical member, in one row at the center
in a cylindrical pipe 47 which has the same length 31 as those of
the cores 45 (the aligned cores 45 form a first optical member
array 9). The second transparent material (example: BK7 (available
from Schott), with a refractive index of 1.52, thermal expansion
coefficient of 71.times.10.sup.-7/K, and yielding point of
614.degree. C.) has a refractive index which is lower than that of
the first transparent material (example: LaSFn14 (SUMITA KOGAKU),
with a refractive index of 1.83, thermal expansion coefficient of
82.times.10.sup.-7/K, and yielding point of 689.degree. C.) (if the
refractive index of the first transparent material is higher than
that of the second transparent material, the curved surfaces of
first optical acting portions 11 are formed into convex curved
surfaces; if the refractive index of the first transparent material
is lower than that of the second transparent material, the curved
surfaces of the first optical acting portions 11 are formed into
concave curved surfaces). When aligning the cores 45, a central
axis O.sub.47 of the cylindrical pipe 47 and central axes O.sub.45
of the plurality of cores 45 are parallel to each other and are
also directed in the same direction as that of secondary drawing to
be described next. The plurality of cores 45 are aligned such that
their side surfaces 42 come into contact with each other. When a
cylindrical one shown in FIG. 2A is to be used as each core 45, the
vertical directions of the cores 45 need not be considered, and it
suffices if the cores 45 are aligned such that their side surfaces
come into contact with each other. Then, to fix the positions of
the plurality of aligned cores 45, a pair of spacers 46 made of the
same constituent material as that of a second optical member 3,
i.e., the second transparent material, are inserted in the gap of
the cylindrical pipe 47 to sandwich the plurality of cores 45
aligned in one row, thus forming the optical lens preform 50. The
optical lens preform 50 is subjected to secondary drawing until a
desired diameter is obtained, as shown in FIG. 4B, and is cut off
the optical lens preform 50, thus obtaining a rod portion 48.
[0044] Since the operations of aligning the plurality of cores 45
and arranging the cores 45 and spacers 46 in the cylindrical pipe
47, as described above, are performed at the stage before the
secondary drawing process, they are done with a sufficiently large
size. As in an optical path converter disclosed in Japanese Patent
Laid-Open No. 7-98402, first optical members may be arranged one by
one in an array to correspond to the respective light-emitting
portions of a semiconductor laser array. It is, however, very
difficult to perform such operation within a very small area. With
the optical lens manufacturing method according to this embodiment,
the alignment operation and arranging operation as described above
can be performed with a sufficiently large size. Hence, the above
inconvenience is eliminated.
[0045] Alternatively, as shown in FIGS. 5A and 5B, cores 45 may be
aligned in two rows at the center of a cylindrical pipe 47 made of
the second transparent material such that the two rows are parallel
to each other, and gaps may be filled with three spacers 46, thus
forming an optical lens preform 51 (see FIG. 5A). In this case, an
optical lens is formed in which two rows of the first optical
member arrays 9 are buried in the second optical member.
Alternatively, as shown in FIGS. 6A and 6B, an optical lens preform
52 may be formed by using cores 245 shown in FIG. 3B. As has been
described earlier, the cores 245 are integrally molded, so the step
of aligning a plurality of cores in a cylindrical pipe 47 can be
omitted.
[0046] FIGS. 7A to 7D are schematic views showing the steps in a
method of manufacturing a buried type optical lens according to the
first embodiment, which follow the step in FIG. 4B. The rod portion
48 obtained in FIG. 4B is subjected to slicing (note that the step
of cutting the cores 45 and rod portion 48 off the drawn optical
lens preform may also be included in this "slicing"), to obtain an
optical lens form 60 shown in FIG. 7A. The optical lens form 60 is
subjected to cutting to remove unnecessary portions of a spacer 46,
and its outer portion is polished, thus forming an optical lens 1
with a desired size (see FIG. 7B).
[0047] Since the optical lens 1 fabricated in this manner has a
first optical member array 9 formed by arraying first optical
members 2, it can cope with a semiconductor laser array in which a
plurality of light-emitting portions are arrayed. As the first
optical member array 9 is buried in a second optical member 3, the
uneven portions of first optical acting portions 11 are not exposed
to the outside. Hence, dust will not be accumulated in the uneven
portions to form a shadow, and the optical lens 1 with a good
light-emitting performance is realized. As the optical lens 1 is
reinforced by the second optical member 3, it has a large strength
as well.
[0048] With the optical lens manufacturing method according to the
first embodiment, the manufacture is performed by using two optical
members. Thus, the manufacture can be performed by appropriately
setting the refractive indices of the two optical members, and
particularly by setting a large difference between the refractive
indices. As is disclosed in Japanese Patent Laid Open Nos. 7-287104
and 7-98402, lenses with different refractive indices may be formed
on the outer surface of one optical lens by utilizing ion exchange.
In this case, however, a sufficiently large refractive index
difference cannot be provided between that portion which has been
subjected to ion exchange and that portion which has not, which is
inconvenient. In the optical lens manufacturing method according to
this embodiment, since the optical lens can be formed of different
optical members, this inconvenience is solved.
[0049] Furthermore, the temperature required for the secondary
drawing process is set to be lower than the yielding point of the
first transparent material and higher than that of the second
transparent material. Thus, the first optical members 2 made of the
first transparent material are not dissolved in the secondary
drawing process, and the second optical member 2 made of the second
transparent material is dissolved in the secondary drawing process.
The dissolved optical member fills the gap between the first and
second optical members 2 and 3. Hence, an optical lens with no gap
is fabricated.
[0050] In the first embodiment, a second optical acting portion 12
is formed by cutting and polishing the spacer 46 portion in the
final process, so the optical lens 1 as shown in FIG. 7C can be
fabricated. Alternatively, a second optical acting portion 12 may
be formed by adhering optical members made of the second
transparent material. As a result, the first and second optical
acting portions are respectively formed on the first optical member
2 and the second optical member, so an optical lens 71 capable of
optically acting on the incident light beams in various manners is
realized. Furthermore, at the stage of the optical lens form 60,
machining may be performed so that any one of the respective side
surfaces of the first optical member array 9 which does not have a
first optical acting portion may be exposed, thereby forming an
optical lens 72 as shown in FIG. 7D. As the portion not having an
optical acting portion is removed, the optical lens can be
downsized.
[0051] As shown in FIGS. 8A and 8B, when the rod portion 48
obtained in FIG. 4B is to be sliced, slicing may be performed thick
to form an optical lens form 61 (see FIG. 8A). Then, an optical
lens 73 that can cope even with a semiconductor laser array formed
by stacking a plurality of stages is realized. As shown in FIGS. 9A
and 9B, when the rod portion 48 is to be sliced, slicing may be
performed to be inclined by 45.degree. with respect to the axial
direction (i.e., the drawing direction of secondary drawing) of the
rod portion 48. Then, an optical lens form 63 in which the
respective first optical members are arrayed to be inclined with
respect to the axial directions of first optical member arrays 9
can be fabricated. FIG. 9B shows an optical lens 74 fabricated by
cutting this optical lens form 63. In the optical lens 74, two rows
of first optical member arrays 9, in each of which respective first
optical members 2 are inclined by 45.degree., are arrayed. The
light beams becoming incident on an optical lens 1 are rotated by
the two rows of the first optical member arrays 9 through
90.degree. about the optical axis as the central axis, and are
emitted.
[0052] FIGS. 10A to 10D are schematic views showing the steps in a
method of manufacturing an optical lens according to the second
embodiment. A plurality of first optical members 2 each fabricated
by either one of the methods of FIGS. 1 to 3 are arrayed in one
row, as shown in FIG. 10A, to form a first optical member array 9.
The first optical member array 9 is vertically sandwiched by a pair
of second optical members 3, thereby forming an optical lens
preform 50 (see FIG. 10B; in FIG. 10B, the optical lens preform 50
is mounted in a heating compressor 80 (to be described later)).
Each first optical member 2 fabricated by either one of the methods
of FIGS. 1 to 3 has been subjected to drawing until it corresponds
to the pitch width of each light-emitting portion of the
semiconductor laser array. In the second embodiment, the first
transparent material as the material that forms the first optical
members 2 and the second transparent material as the material that
forms the second optical members 3 may be glass or a plastic
material. The optical lens preform 50 is set in the heating
compressor 80, as shown in FIG. 10C, and is heated (700.degree. C.
) and compressed (50 kg/cm.sup.2) from the above and below, the
forward and backward, and the left and right. In this manner, an
optical lens form 64 is formed (see FIG. 10D). The subsequent steps
are the same as those in the first embodiment. With the
manufacturing method according to the second embodiment, an optical
lens can be fabricated by performing drawing operation once.
[0053] FIGS. 11A to 11C are schematic views showing the steps in a
method of manufacturing an optical lens according to the third
embodiment. A plurality of first optical members 2 each fabricated
by either one of the methods of FIGS. 1 to 3 are arrayed in one
row, as shown in FIG. 11A, to form a first optical member array 9.
The first optical member array 9 is solidified with a transparent
resin 90 from around to form an optical lens preform 50. In the
same manner as in the second embodiment, each first optical member
2 fabricated by any one of the methods of FIGS. 1 to 3 has been
subjected to drawing until it corresponds to the pitch width of
each light-emitting portion of the semiconductor laser array. In
the third embodiment, the first transparent material as the
material that forms the first optical members 2 may be glass or a
plastic material. This optical lens preform 50 is sliced to obtain
an optical lens form 65 as shown in FIG. 11C. The subsequent steps
are the same as those in the first embodiment. With the
manufacturing method according to the third embodiment, an optical
lens can be fabricated by performing drawing operation once, in the
same manner as in the second embodiment. Since the resin used for
hardening transmits light, it serves as an optical member, and can
also form the second optical acting portion 12 as shown in FIG.
7C.
[0054] As has been described above, with the optical lens
manufacturing methods according to the respective embodiments of
the present invention, the shape of the optical lens, and
particularly the shape of the first optical acting portion, can be
determined at the stage of the preform before primary drawing.
Thus, the preform is machined with a sufficiently large size.
Therefore, the machining operations can be performed simply and
accurately, and the burden in the manufacture is also reduced.
[0055] With the buried type optical lens manufacturing methods
according to the respective embodiments of the present invention,
at the stage of the preform before secondary drawing, the first
optical member array can be arranged to be surrounded by the second
optical member. Thus, the preform is fabricated with a sufficiently
large size. Therefore, the arranging operations can be performed
simply and accurately, and the burden in the manufacture is also
reduced.
[0056] Although the present invention has been described in detail
by means of the first to third embodiments, note that the present
invention is not limited to these embodiments that merely indicate
the best mode in practicing the present invention, but incorporates
any modifications of the present invention within the scope of the
claims of the present invention, and that the shape, size,
arrangement, and constitution of the present invention can be
changed.
[0057] For example, as the action against the light beam, a case
has been described wherein the light beams emitted from the
respective light-emitting portions of a semiconductor laser array
are collimated and emitted. Alternatively, the light beams may be
condensed in place of being collimated.
[0058] As described above, the optical lens manufacturing method
according to the present invention is suitable for acting on a
light beam emitted from a light-emitting device, and particularly
suitable for acting on light beams emitted from the respective
light-emitting portions of a light-emitting device in which a
plurality of light-emitting portions are arrayed.
* * * * *