# US 2014/0153104 A1 · Fabrication of Lenses Using High Viscosity Liquid

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- Number: US 2014/0153104 A1
- Document ID: US20140153104A1
- Status: Published application
- Kind: A1
- Application number: 13/693,870
- Filed: 2012-12-04
- Published: 2014-06-05
- Earliest claimed: 2012-12-04
- Assignees: Ricoh Company, Ltd.
- Inventors: Sri Rama Prasanna Pavani; Brian P. McCall
- Web page: https://patentgrep.com/patent/US20140153104A1

## CPC

- G02B 3/0012: {characterised by the manufacturing method}
- B29D 11/00307: {Producing lens wafers}
- B29D 11/00365: {Production of microlenses (lenticular sheets B29D11/00278)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)

## Abstract

A method for fabricating millimeter and sub-millimeter size lenses using a high viscosity curable liquid, such as epoxy. The method comprises dispensing a predetermined volume of the curable liquid onto a substrate. The curable liquid preferably has a viscosity higher than 100 cps. Additionally, to reduce spherical aberration, the curable liquid can be cured upside down to leverage the effects of gravity.

## Claims

### Claim 1

A method for fabricating a lens on a substrate, the method comprising:
making contact between a drop of curable liquid and a substrate;
dispensing a predetermined volume of the curable liquid from a dispenser onto the substrate while the curable liquid is in contact with the substrate, the curable liquid having a viscosity of at least 100 cps; and
curing the curable liquid to a solid form.

### Claim 2 (depends on 1)

The method of claim 1, wherein the curable liquid is a liquid epoxy or a liquid polymer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the lens has a circular aperture with diameter of not more than 1 mm.

### Claim 4 (depends on 1)

The method of claim 1, wherein the lens has a circular aperture with diameter of not more than 500 μm.

### Claim 5 (depends on 1)

The method of claim 1, wherein the curable liquid has a viscosity of at least 200 cps.

### Claim 6 (depends on 1)

The method of claim 1, wherein the curable liquid is cured while supported by the substrate.

### Claim 7 (depends on 1)

The method of claim 1, wherein the curable liquid is cured while suspended from the substrate.

### Claim 8 (depends on 1)

The method of claim 1, wherein the substrate is a featureless, planar substrate.

### Claim 9 (depends on 1)

The method of claim 1, wherein the substrate is transparent.

### Claim 10 (depends on 1)

The method of claim 1, wherein the substrate is homogeneous with a uniform refractive index.

### Claim 11 (depends on 1)

The method of claim 1, wherein the substrate is inhomogeneous with a gradient in refractive index.

### Claim 12 (depends on 1)

The method of claim 1, further comprising:
dispensing predetermined volumes of curable liquid from the dispenser onto the substrate at multiple locations, the liquid having a viscosity of at least 100 cps; and
curing the curable liquid to a solid form to form an array of lenses.

### Claim 13 (depends on 12)

The method of claim 12, wherein the predetermined volumes of curable liquid are dispensed simultaneously at multiple locations on the substrate.

### Claim 14 (depends on 12)

The method of claim 12, wherein the predetermined volumes of liquid are dispensed sequentially at each of the multiple locations on the substrate.

### Claim 15 (depends on 1)

An lens manufactured by the process of claim 1.

### Claim 16 (depends on 1)

An array of lenses, wherein each lens is manufactured by the process of claim 1.

### Claim 17

An epoxy or polymer lens on a substrate, the lens characterized by a circular aperture having a diameter, wherein the lens has a height that is at least equal to a height of a curable liquid drop of a same diameter supported by the substrate, the liquid drop having a viscosity of at least 100 cps.

### Claim 18 (depends on 17)

The lens of claim 17 wherein the substrate is a featureless, planar substrate.

### Claim 19 (depends on 17)

The lens of claim 17 wherein a surface of the lens is characterized by
z

(
r
)
=
r
/
R
2
1
+
1
-
(
r
/
R
)
2
+
∑
n
=
2
N

a
n

r
2

n
where z(r) is a height of the lens at radius r, R is a radius of curvature at the center of the lens,
a
2
=
-
1
32

R

(
1
R
2
+
1
L
c
2
)
a
3
=
-
1
576

R

(
23
R
4
+
1
2

L
c
4
+
47
R
2

L
c
2
)
a
4
=
-
1
819

R

(
375
R
6
+
1
9

L
c
6
+
3745
9

R
4

L
c
2
+
371
9

R
2

L
c
4
)
and Lc is a characteristic length of the epoxy or polymer forming the lens.

### Claim 20 (depends on 17)

The lens of claim 17 wherein a surface of the lens is characterized by
z

(
r
)
=
r
/
R
2
1
+
1
-
(
r
/
R
)
2
+
∑
n
=
2
N

a
n

r
2

n
where z(r) is a height of the lens at radius r, R is a radius of curvature at the center of the lens,
a
2
=
-
1
32

R

(
1
R
2
-
1
L
c
2
)
a
3
=
-
1
576

R

(
23
R
4
+
1
2

L
c
4
-
47
R
2

L
c
2
)
a
4
=
-
1
819

R

(
375
R
6
-
1
9

L
c
6
-
3745
9

R
4

L
c
2
+
371
9

R
2

L
c
4
)
and Lc is a characteristic length of the epoxy or polymer forming the lens.