U.S. patent application number 14/700217 was filed with the patent office on 2015-08-20 for method and device for producing a microlens.
This patent application is currently assigned to EV GROUP GMBH. The applicant listed for this patent is EV Group GmbH. Invention is credited to Michael Kast, Erich Thallner, Markus Wimplinger.
Application Number | 20150231840 14/700217 |
Document ID | / |
Family ID | 42555430 |
Filed Date | 2015-08-20 |
United States Patent
Application |
20150231840 |
Kind Code |
A1 |
Thallner; Erich ; et
al. |
August 20, 2015 |
METHOD AND DEVICE FOR PRODUCING A MICROLENS
Abstract
A method for producing a microlens with a carrier wafer, in
which a lens in one opening of the carrier wafer is molded into the
carrier wafer by stamping of the lens and to a corresponding device
for executing the method and to a microlens which has been produced
using the method.
Inventors: |
Thallner; Erich; (St.
Florian, AT) ; Wimplinger; Markus; (Ried im Innkreis,
AT) ; Kast; Michael; (Wels, AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EV Group GmbH |
St. Florian am Inn |
|
AT |
|
|
Assignee: |
EV GROUP GMBH
St. Florian am Inn
AT
|
Family ID: |
42555430 |
Appl. No.: |
14/700217 |
Filed: |
April 30, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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13583652 |
Sep 28, 2012 |
9052422 |
|
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PCT/EP10/02065 |
Mar 31, 2010 |
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14700217 |
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Current U.S.
Class: |
264/1.7 |
Current CPC
Class: |
G02B 3/0031 20130101;
B29D 11/00375 20130101 |
International
Class: |
B29D 11/00 20060101
B29D011/00 |
Claims
1. Method for producing a microlens with a carrier wafer, the
carrier wafer having an inner ring extending between opposite
facing surfaces of the carrier wafer, the inner ring defining an
opening of the carrier wafer for accommodating the microlens
therein, the method comprising a step of: molding the microlens
into the carrier wafer by stamping of the microlens using two lens
dies each having a contact surface dimensioned to adjoin a
corresponding mating surface of the carrier wafer for coplanar
alignment of the lens dies during stamping, wherein a thickness of
the carrier wafer defines a thickness of the formed micro lens.
2. Method as claimed in claim 1, wherein the carrier wafer is
located outside a beam path of the microlens.
3. Method as claimed in claim 1, wherein each of a plurality of
microlenses is molded into a corresponding opening of a carrier
wafer matrix which encompasses corresponding carrier wafers during
stamping.
4. Method as claimed in claim 1, further comprising the following
sequence: alignment and fixing of a lower lens die with the opening
of the carrier wafer, delivery of a lens material which forms the
microlens into the opening, stamping of the microlens by acting on
the lens material with an upper lens die and curing of the
microlens.
5. Method as claimed in claim 1, wherein a holding structure
extends from an annular surface of the inner ring at a location
spaced from both of the opposite facing surfaces of the carrier
wafer, and wherein the holding structure is an annular projection
extending from the annular surface of the inner ring.
6. Method as claimed in claim 1, wherein a holding structure
extends from an annular surface of the inner ring at a location
spaced from both of the opposite facing surfaces of the carrier
wafer, and wherein the holding structure is a plurality of
projections extending from the annular surface of the inner
ring.
7. Method for producing a microlens with a carrier wafer, the
carrier wafer having an inner ring extending between opposite
facing surfaces of the carrier wafer, the inner ring defining an
opening of the carrier wafer for accommodating the microlens
therein, the method comprising a step of: molding the microlens
into the carrier wafer by stamping of the microlens using two lens
dies each having a contact surface dimensioned to adjoin a
corresponding mating surface of the carrier wafer for coplanar
alignment of the lens dies during stamping, wherein a coefficient
of thermal expansion of the microlens is greater than a coefficient
of thermal expansion of the carrier wafer such that gap is formed
between the microlens and the carrier wafer during said step of
molding.
8. Method as claimed in claim 7, wherein the carrier wafer is
located outside a beam path of the microlens.
9. Method as claimed in claim 7, wherein each of a plurality of
microlenses is molded into a corresponding opening of a carrier
wafer matrix which encompasses corresponding carrier wafers during
stamping.
10. Method as claimed in claim 7, further comprising the following
sequence: alignment and fixing of a lower lens die with the opening
of the carrier wafer, delivery of a lens material which forms the
microlens into the opening, stamping of the microlens by acting on
the lens material with an upper lens die and curing of the
microlens.
11. Method as claimed in claim 7, wherein a holding structure
extends from an annular surface of the inner ring at a location
spaced from both of the opposite facing surfaces of the carrier
wafer, and wherein the holding structure is an annular projection
extending from the annular surface of the inner ring.
12. Method as claimed in claim 7, wherein a holding structure
extends from an annular surface of the inner ring at a location
spaced from both of the opposite facing surfaces of the carrier
wafer, and wherein the holding structure is a plurality of
projections extending from the annular surface of the inner
ring.
13. Method for producing a microlens with a carrier wafer, the
carrier wafer having an inner ring extending between opposite
facing surfaces of the carrier wafer, the inner ring defining an
opening of the carrier wafer for accommodating the microlens
therein, wherein a holding structure extends from an annular
surface of the inner ring at a location spaced from both of the
opposite facing surfaces of the carrier wafer, the method
comprising a step of: molding the microlens into the carrier wafer
by stamping of the microlens using two lens dies each having a
contact surface dimensioned to adjoin a corresponding mating
surface of the carrier wafer for coplanar alignment of the lens
dies during stamping, wherein a plurality of minor projections
define the holding structure.
14. Method as claimed in claim 13, wherein the carrier wafer is
located outside a beam path of the microlens.
15. Method as claimed in claim 13, wherein each of a plurality of
microlenses is molded into a corresponding opening of a carrier
wafer matrix which encompasses corresponding carrier wafers during
stamping.
16. Method as claimed in claim 13, further comprising the following
sequence: alignment and fixing of a lower lens die with the opening
of the carrier wafer, delivery of a lens material which forms the
microlens into the opening, stamping of the microlens by acting on
the lens material with an upper lens die and curing of the
microlens.
17. Method for producing a microlens with a carrier wafer, the
carrier wafer having an inner ring extending between opposite
facing surfaces of the carrier wafer, the inner ring defining an
opening of the carrier wafer for accommodating the microlens
therein, the method comprising a step of: molding the microlens
into the carrier wafer by stamping of the microlens using two lens
dies each having a contact surface dimensioned to adjoin a
corresponding mating surface of the carrier wafer for coplanar
alignment of the lens dies during stamping, wherein a spacer
extends from a surface of at least one of the two lens dies, said
spacer dimensioned to extend through an opening formed in the
carrier wafer to contact an opposite lens die such that the spacer
defines a thickness of the formed microlens.
18. Method as claimed in claim 17, wherein the carrier wafer is
located outside a beam path of the microlens.
19. Method as claimed in claim 17, wherein each of a plurality of
microlenses is molded into a corresponding opening of a carrier
wafer matrix which encompasses corresponding carrier wafers during
stamping.
20. Method as claimed in claim 17, further comprising the following
sequence: alignment and fixing of a lower lens die with the opening
of the carrier wafer, delivery of a lens material which forms the
microlens into the opening, stamping of the microlens by acting on
the lens material with an upper lens die and curing of the
microlens.
21. Method as claimed in claim 17, wherein a holding structure
extends from an annular surface of the inner ring at a location
spaced from both of the opposite facing surfaces of the carrier
wafer, and wherein the holding structure is an annular projection
extending from the annular surface of the inner ring.
22. Method as claimed in claim 17, wherein a holding structure
extends from an annular surface of the inner ring at a location
spaced from both of the opposite facing surfaces of the carrier
wafer, and wherein the holding structure is a plurality of
projections extending from the annular surface of the inner ring.
Description
RELATED APPLICATIONS
[0001] The present application is a continuation of U.S.
application Ser. No. 13/583,652, filed Sep. 28, 2012, which is a
U.S. National Stage Application of International Application No.
PCT/EP2010/002065, filed Mar. 31, 2010, said patent applications
hereby fully incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to a microlens, a method for
producing a microlens and a device for producing a microlens.
BACKGROUND OF THE INVENTION
[0003] Primarily microlenses are used for devices which require an
optical focusing means, such as for example cameras and mobile
phones. As a result of miniaturization pressure, the functional
components are becoming increasingly smaller; this also applies to
microlenses of the generic type. The further the microlenses are to
be miniaturized, the more difficult their optically correct
production becomes because at the same time there is enormous cost
pressure for microlenses to be ideally produced in large-scale
production.
[0004] In the prior art microlenses are produced on a carrier
substrate by various production methods, as shown for example in
U.S. Pat. No. 6,846,137 B1, U.S. Pat. No. 5,324,623, US 5,853,960
and U.S. Pat. No. 5,871,888. It is common to all the aforementioned
methods that a certain thickness is necessary in principle and the
light which passes through the microlens must pass through not only
the lens, but also the carrier substrate.
[0005] As a result of the simultaneously required high quality and
the demands for higher resolution with simultaneously high
brilliance, which depends among others on the thickness and the
number of optics along the optical axis, therefore the beam path,
further optimization of the microlenses according to the prior art
is desirable.
[0006] Moreover there is a requirement for radiant efficiency which
is as high as possible and which is decisive especially for micro
optics systems, since the image sensor occupies a generally very
small area on which light is incident.
[0007] U.S. Pat. No. 6,049,430 shows a lens which has been inserted
in an opening of a carrier substrate, and the production process
shown in FIG. 2 requires a plurality of steps and is therefore
complex and due to the production accuracies which can be attained
here would be too inaccurate for the aforementioned requirements.
The plurality of materials to be used is also a disadvantage.
SUMMARY OF THE INVENTION
[0008] Therefore the object of this invention is to devise a
microlens which can be produced especially in large-scale
production with a radiant efficiency and brilliance as high as
possible, which can be produced by a method as claimed in the
invention and a device as claimed in the invention in a simple
manner which is suitable for large-scale production with a flexible
mold.
[0009] This object is achieved with the features of the claims.
Advantageous developments of the invention are given in the
dependent claims. All combinations of at least two of the features
given in the specification, the claims and/or the figures also fall
within the framework of the invention. At the given value ranges,
values within the indicated limits will also be disclosed as
boundary values and will be claimed in any combination.
[0010] The invention is based on the idea of producing a microlens
by molding a lens directly into the carrier wafer so that the
carrier wafer does not obstruct the light beam passing through the
lens or is located outside the beam path. Thus the lens is molded
from two sides of the carrier wafer by an upper and a lower lens
die so that a high precision microlens can be produced by
especially collinear alignment of the upper lens die to the lower
lens die and/or to the carrier wafer. Deviating from the existing
procedure in the prior art makes it possible as claimed in the
invention to make the lens mold more flexible, especially in the
region of the lower lens side which had been previously covered by
the carrier wafer.
[0011] The rigid carrier wafer provides for stability of shape in
the production of the lens since it generally entails
expansion/shrinkage of the lens.
[0012] In particular, in the simultaneous production of a plurality
of lenses with one carrier wafer matrix and two lens die matrices
which is enabled by this method and the device as claimed in the
invention, the carrier wafer ensures moreover the integrity of the
optical axes of the lenses to one another. The respective grid
positions of each corresponding upper and lower die and the
corresponding opening of the carrier wafer can thus be exactly
aligned since the carrier wafer is not subjected to changes in size
in production. With one carrier wafer matrix and the two
corresponding lens die matrices, at a carrier wafer diameter of 200
mm roughly 2000 lenses can be produced with one process run as
claimed in the invention.
[0013] As claimed in the invention, there is a microlens negative
on each lens die whose shape determines the curvature of the
respective side of the microlens produced with the method as
claimed in the invention. The shape of the lenses can be made
convex, planar or concave. The lens profile can be spherical or
aspherical as claimed in the invention.
[0014] The lens is formed from UV-curable or thermally curable lens
material, one of the two lens dies being made UV-transparent in the
case of the UV-curable lens material. The lens material as claimed
in the invention is at least largely, preferably completely free of
solvent and is suitable for complete crosslinking.
[0015] The carrier wafer which is provided as claimed in the
invention and into which the lens can be molded or is molded, is
used for holding and fixing of the lens in the microlens which has
been produced as claimed in the invention and especially as spacer
between the upper and the lower lens die so that among others the
thickness of the microlens is influenced by the thickness of the
carrier wafer. The carrier wafer can also be advantageously used
for producing a plurality of microlenses by many lenses being
molded into the carrier wafer and being divided later into
individual microlenses. To the extent the carrier wafer is made as
a ring with an opening for holding the lens, the lens is held and
stabilized on its entire circumference by the carrier wafer. The
lens ring can be made square, semicircular, triangular, elliptical
on its inside and/or its outside, on the inner ring be
advantageously a holding structure, especially projections, being
designed for more effective fixing of the lens in the carrier
wafer, preferably as openings of the carrier wafer, therefore in
one piece with the carrier wafer. Preferably the holding structures
project over the inside of the ring by at least one fifth of the
thickness of the carrier wafer.
[0016] Alternatively the holding structure is made as surface
roughness of the inner ring of the carrier wafer on which the lens
material and the cured lenses are held in the direction of the
optical axis.
[0017] To avoid thermal expansion or thermal stresses it is
advantageously provided that the lens material and the carrier
wafer have a coefficient of thermal expansion of roughly the same
magnitude. To the extent the lens and the carrier wafer have a
different coefficient of thermal expansion the lens as claimed in
the invention is made such that the shape of the lens at different
temperatures essentially scales so that the lens in different
temperature states is self-similar and hardly changes its optical
properties. In this case it is advantageous if the lens as claimed
in the invention has a greater coefficient of thermal expansion in
the cured state than the carrier wafer. In this way, in the
production of the microlens a minimum empty space is formed between
the carrier wafer and the lens which is used as a buffer for the
expansion of the lens at different temperatures in the production
of the microlens due to the larger coefficient of thermal expansion
of the lens when the lens is cooled during production. As claimed
in the invention in the production of the microlens, especially in
a UV-curing lens material there can be heating during curing of the
lens material in order to achieve the aforementioned effect.
[0018] Accordingly the lens as claimed in the invention is
connected positively to the carrier wafer, especially to the inner
ring of the carrier wafer.
[0019] The lens dies in one advantageous embodiment consist of a
carrier substrate and a microlens negative which is fixed on the
carrier substrate. According to one embodiment of the lens die at
least one lens die is provided with a drain for excess lens
material.
[0020] The process for producing the microlens preferably proceeds
as follows:
[0021] The microlens negative of the lower lens die is fixed,
especially by fixing of the lens die by a receiving means for
accommodating the lower lens die. Then the carrier wafer is
aligned/adjusted to the microlens negative of the lower lens die
such that the optical axis of the microlens negative and the
longitudinal center axis of the carrier wafer are collinear.
Alternatively and especially for production of several lenses
simultaneously with a carrier wafer the carrier wafer is adjusted
coplanarly with the carrier substrate of the lower lens die. Then
the carrier wafer is placed and fixed on the carrier substrate of
the microlens negative, therefore on the lens die. Fixing is
conceivable by vacuum structures in the lens die or
electrostatically by electrostatic means machined into the lens
die, but also mechanically by clamping and/or adhesion.
[0022] Then lens material, especially a UV-curable or
thermoplastically curable polymer, is introduced into the opening
of the carrier wafer by way of the microlens negative of the lower
lens die, the viscosity of the lens material during introduction
being chosen such that the lens space formed by the inner ring of
the carrier wafer and the lens die can be filled free of bubbles.
The amount of lens material added is such that in subsequent
embossing of the lens there is enough lens material to fill the
microlens negative of the upper lens die.
[0023] In one alterative embodiment introduction takes place over
the entire surface on the carrier wafer/carrier wafer matrix, as a
result of which the opening/openings is/are filled and excess lens
material or lens material which is needed for the lens structures
which project over the carrier wafer covers the carrier
wafer/carrier wafer matrix.
[0024] According to another alternative embodiment of the
invention, the lens material is delivered individually into the
opening(s) of the carrier wafer/carrier wafer matrix, especially by
metering with a droplet dispenser or with a pipette.
[0025] Then the optical axis of the upper lens die is calibrated
collinearly with the optical axis of the lower lens die or the lens
negative of the lower lens die and/or with the longitudinal center
axis of the carrier wafer. Then the upper lens die is pressed with
pressure onto the lower lens die and the carrier wafer which is
located in between. In the case of UV curing the lens material is
irradiated by means of UV light with relatively high intensity
through the upper lens die which in this case is transparent or
UV-permeable, and/or through the lower lens die, and the polymer is
crosslinked. In thermoplastic curing the material of the lens die
is provided with relatively high thermal conductivity in order to
promote heat transport.
[0026] The alignment of the lens dies with the carrier wafer takes
place by an alignment mechanism, especially with an alignment
precision of less than 500 .mu.m, especially less than 200 .mu.m,
preferably less than 100 .mu.m, ideally less than 70 .mu.m
deviation and/or with optical alignment means with an alignment
precision of less than 10 .mu.m, especially less than 5 .mu.m,
preferably less than 3 .mu.m deviation. Optical alignment is
especially advantageous for the alignment of the upper and lower
lens die or the upper and lower lens die matrix. Optical means are
especially lasers or microscopes which enable exact alignment by
markings on the lens dies or on the lens die matrices.
[0027] According to one especially preferred embodiment of the
invention the lens die is aligned, especially in addition to the
alignment on the carrier wafer, by parallel alignment of the lens
dies to one another, the position of the optical axis/axes of the
lens negatives being taken into account.
[0028] By the contact surfaces of the lens dies adjoining the
corresponding mating surfaces of the carrier wafer for coplanar
alignment of the lens dies during stamping, the lens dies are
aligned using the especially parallel opposite mating surfaces of
the carrier wafer, as a result of which the optical axes of the
lens negatives are exactly aligned.
[0029] As claimed in the invention a deviation of less than 10
.mu.m over the width of each lens which is between 100 .mu.m and 6
mm means parallel. At most the deviation of the parallelism is
therefore 10%, especially less than 7%, preferably less than 5%,
even more preferably less than 3%, ideally less than 1.5%. Thus
essentially ideal agreement of the optical axes is enabled. The
height of the lenses is conventionally between 50 and 500 .mu.m,
and the height for the microlens as claimed in the invention
compared to the prior art can be reduced essentially by the width
of the carrier wafer.
[0030] According to one embodiment of the invention, on the
microlens, especially parallel to the optical axis of the lens,
there is a self-centering structure, especially as an opening of
the carrier wafer, which is used for example for automatic
alignment of the microlens with another microlens which has a
corresponding, inverted structure, especially in the form of
orientation ribs. The self-alignment works according to the
key-lock principle or in the manner of a tongue-in groove joint. A
cone-like configuration of the tongue-in-groove joint is especially
preferred.
[0031] The description of the method and of the device for
producing an individual microlens relates analogously to the
production of a plurality of microlenses with the feature that it
is enabled only by the configuration as claimed in the invention.
Instead of an upper lens die an upper lens die matrix is used which
comprises several lens dies, especially as a one-piece lens die
structure. The lower lens die matrix is formed analogously. The
carrier wafer as a carrier wafer matrix, especially in the form of
a one-piece carrier wafer structure, is provided with a plurality
of openings.
[0032] For action in the preferred alternative in which the lens
die matrices are aligned on the contact surfaces of the lens die
matrices, the carrier wafer matrix can be penetrated by a spacer of
the upper and/or lower lens die matrix which forms the contact
surface at the time and dictates the thickness of the lens.
[0033] According to one independent version of the invention, the
carrier wafer after producing the microlens is at least partially,
preferably completely removed. In this way the dimensions and the
weight of the lens are further reduced. Removal takes place
preferably by ejecting the lens from the carrier wafer which is
provided especially with a holding structure with minor
projections. Minor projections are made especially as surface
roughness of the inner ring.
[0034] Other advantages, features and details of the invention will
become apparent from the following description of preferred
exemplary embodiments and using the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 shows a schematic cross sectional view of a microlens
matrix as claimed in the invention consisting of a plurality of
lenses molded into a carrier wafer structure,
[0036] FIG. 2 shows a schematic of a device as claimed in the
invention for producing a microlens as claimed in the
invention,
[0037] FIG. 3 shows a schematic of a microlens matrix as claimed in
the invention consisting of a plurality of lenses molded in a
carrier wafer structure according to one alternative
embodiment,
[0038] FIG. 4 shows a schematic of a device as claimed in the
invention for producing a microlens as claimed in the invention
according to one alternative embodiment,
[0039] FIG. 5 shows a schematic of shapes of a holding structure as
claimed in the invention, and
[0040] FIG. 6 shows a schematic of a device as claimed in the
invention for producing a plurality of microlenses.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0041] In the figures the same parts and parts with the same
function are labeled with the same reference numbers.
[0042] FIG. 1 shows a microlens matrix 31 in cross section which
consists of a carrier wafer structure 32 and a plurality of lenses
14 molded into openings 2 of the carrier wafer structure 32 or the
later carrier wafer 17. The microlens matrix 31 can be separated by
known cutting methods into individual microlenses 1, as is shown
isolated in the exploded representation in FIG. 2.
[0043] The microlenses 1 can be produced as microlens matrix 31 in
large-scale production, but can also be produced individually. FIG.
2 schematically shows production using an individual microlens
1.
[0044] As shown in FIG. 2, a lower lens die 18 consisting of a
carrier substrate 21 and a lens mold 20 which has been fixed,
especially cemented, on the carrier substrate 21 can be
accommodated on receiving means of the device as claimed in the
invention which are not shown. In large-scale production on the
carrier substrate 21 there can be a plurality of lens molds 20 or
one lens mold 20 with a plurality of lens negatives 19, the lens
negatives 19 or the lens molds 20 being applied to the carrier
substrate 21 such that they can be aligned flush with the openings
2 which are shown in FIG. 1.
[0045] The lens negative 19 is surrounded by a contact surface 22
which is located orthogonally to the optical axis of the lens
negative 19 and on which the carrier wafer 17 comes into contact
with a corresponding mating surface 23 which is annular in this
exemplary embodiment, forming a seal.
[0046] As soon as the carrier wafer 17, as shown in FIG. 2, is
aligned with its longitudinal center axis to the optical axis A,
the carrier wafer 17 with its mating surface 23 is fixed on the
contact surface 22 so that an inner ring 16 of the carrier wafer 17
and the lens mold 20 form a lens space 3 into which the lens
material which forms the lens 14 can be introduced via delivery
means. After delivering the lens material into the lens space 3 the
lens 14 is stamped as described below.
[0047] For this purpose an upper lens die 9 which is provided by
receiving means for accommodating an upper lens die 9 can be
aligned by alignment means for alignment of the upper lens die 9
with the opening 14 and/or the lower lens die 18, especially to the
optical axis A of a lens negative 12 of a lens mold 11 applied on a
carrier substrate 10. The upper lens die 9 is formed analogously to
the lower lens die 18 and has a contact surface 8 for especially
sealing contact of the upper lens die 9 with one mating surface 7
of the carrier wafer 17. The mating surface 7 is located opposite
the mating surface 23 and parallel to it.
[0048] After alignment of the upper lens die 9, the upper lens die
9 is lowered along the optical axis A onto the carrier wafer 17 and
subjected to pressure, the corresponding counter pressure being
applied via the lower lens die 18. The lens material fills the lens
space 3 without bubbles and possible excess lens material can drain
or be sucked out of the lens space 3 via a drain system which is
not shown in the figures.
[0049] According to one preferred embodiment of the invention the
lens material can be optimally subjected to pressure when a vacuum,
especially with a pressure <500 mbar, preferably <300 mbar,
even more preferably <than 200 mbar, ideally <100 mbar, is
applied by vacuum means at the same time in the opening, especially
between the upper lens die and the carrier wafer.
[0050] According to one still more preferred embodiment the vacuum
during pressurization is <70 mbar, especially <40 mbar,
preferably <15 mbar, even more preferably <5 mbar.
[0051] The lens material is cured via curing means of the device so
that a hard lens 14 is formed which corresponds to the shape
according to the lens space 3. The curing means can be a light
source for UV light for UV-curable lens material or heating means
for thermoplastically curable polymer as lens material.
[0052] By the carrier wafer 17 which has the inner ring 16 and an
outer ring 24 having a holding structure 25 in the form of a
projection which projects sharply in the direction of the optical
axis A of the inner ring 16 in the illustrated exemplary embodiment
as shown in FIG. 2, the lens 14 and the carrier wafer 17 form a
positive connection which cannot be nondestructively broken. As
shown in FIG. 2, holding structure 25 extends from inner ring 16 at
a location spaced from mating surfaces 7, 23 of carrier wafer 17.
As such, holding structure 25 projects into an outer peripheral
portion of lens 14.
[0053] Alternative shapes of the holding structure 25 are shown in
FIG. 5. The alternative embodiment shown in FIGS. 3 and 4
corresponds, with the difference that the lens 14' in the exemplary
embodiment shown here acquires a different shape, to the exemplary
embodiment of the invention shown in FIGS. 1 and 2. Other changes
of shape without functional changes relate to the lens 1', the
upper carrier wafer 9' and the lower carrier wafer 18'. Reference
is made to the explanation for FIGS. 1 and 2 as well as 5.
[0054] FIG. 6 shows a device for executing the method as claimed in
the invention with receiving means 50 for accommodating the upper
lens die matrix 4 which has a plurality of upper lens dies 9, 9'
and receiving means 51 for accommodating the lower lens die matrix
5 which has a plurality of lower lens dies 18, 18'. The receiving
means 50, 51 each consist of a chuck 52, 53 and one die holder 54,
55 which is U-shaped in cross section and which is attached to the
respective chuck 52, 53 for example via vacuum paths (not
shown).
[0055] The upper and/or the lower receiving means 50, 51 can be
moved up and down by a control which is not shown.
[0056] On the lower lens die matrix 5 there are alignment means 56
for alignment of the lower lens die matrix 5. On the upper lens die
matrix 4 there are alignment means 57 for alignment of the upper
lens die matrix 4. On the carrier wafer matrix 32 there are
alignment means 58 for alignment of the carrier wafer matrix
32.
[0057] The alignment means 56, 57 and/or 58 comprise at least one
optical system (not shown) and are controlled by a control unit
which is not shown. Furthermore the alignment means 56, 57 and/or
58 comprise movement means for moving the receiving means 50 and/or
51 parallel to the carrier wafer matrix 32.
[0058] On the lower receiving means 51 there are fixing means 59
for fixing the carrier wafer matrix 32 with the lower lens die
matrix 5 after alignment by the alignment means 56.
[0059] Furthermore, there is delivery means 60 in the form of an
injection means 61 with an especially interchangeable injector 62
which is connected to a storage tank for the lens material via a
flexible fluid line 62. The injection means 61 is made as a drop
dispenser and can approach each opening 2 of the carrier wafer
structure and add a given amount of lens material to it.
[0060] Stamping means for applying pressure apply an adjustable
superficial force along the carrier wafer matrix, especially by
forces Fo and Fu which are applied to the alignment means 50, 51
and which act oppositely in the direction of the carrier wafer
matrix, for example transferring the force by one hydraulic
cylinder at a time.
[0061] Furthermore the device comprises means for curing of the
lens material during stamping, especially a UV light source and/or
heating means which acts on the lens material.
* * * * *