# US 12,007,084 B2 · Natural light homogenization lighting device and method based on free-form surface and sawtooth grating

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- Number: US 12,007,084 B2
- Document ID: US12007084B2
- Status: Granted
- Kind: B2
- Application number: 18/095,398
- Filed: 2023-01-10
- Published: 2023-07-13
- Granted: 2024-06-11
- Earliest claimed: 2022-01-11
- Assignees: Glory Light Technology Co., Ltd.
- Applicants: Glory Light Technology Co., Ltd.
- Inventors: Jian Liu; Xumin Ding; Xinwei Wang; Chenguang Liu
- Web page: https://patentgrep.com/patent/US12007084B2

## CPC

- F21S 11/00: Non-electric lighting devices or systems using daylight {(hybrid lighting devices combining artificial and natural light F21S19/00; roofs with sky-light opening E04D13/03; sun blinds for windows with means for redirecting light onto ceiling of a room E06B9/00; solar heat collectors F24S)}
- F21S 11/002: {characterised by the means for collecting or concentrating the sunlight, e.g. parabolic reflectors or Fresnel lenses}
- F21S 11/007: {characterised by the means for transmitting light into the interior of a building}
- F21V 5/02: of prismatic shape (F21V5/04 takes precedence)
- Y02E 10/52: PV systems with concentrators
- F21S: NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
- F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The present invention discloses a natural light homogenization lighting device and method based on free-form surface and sawtooth grating, and the device can be used as lighting curtains, indoor shutters, window glasses and the like. The device includes a front surface and a rear surface in an array form, the first surface is a free-form surface array, the second surface is a sawtooth surface array, and the free-form surface array is used for collecting outdoor natural light, and transmitting to the sawtooth surface array through the intermediate medium made of the same material between the two surfaces; and the sawtooth surface array is used for deflecting the incident natural light to the indoor space after being refracted by an inclined surface. The present invention can efficiently collect the natural light incident into the window, disperse the light evenly to all directions indoors, homogenize the indoor lighting, and effectively protect the indoor privacy. The device is thin and easy to mass produce, environmentally friendly and pollution-free.

## Claims

### Claim 1

A natural light homogenization lighting device, comprising a front surface array and a rear surface array,
wherein the front surface array is a free-form surface array, the rear surface array is a sawtooth surface array, and the free-form surface array is configured to collect outdoor natural light, and to transmit the outdoor natural light to the sawtooth surface array through an intermediate medium; and
wherein the sawtooth surface array is configured to deflect the incident natural light to an indoor space after the outdoor natural light is refracted by an inclined surface;
wherein the lens form of the free-form surface array is a convex free-form surface or a concave free-form surface, the convex free-form surface or concave free-form surface faces the incident direction of natural light, and the normal of the lens surface forms an acute angle to the incident angle of natural light;
for the convex free-form surface, an expression of the thickness d 1 at different positions x1 and y1 is
d
1
(
x
1
,
y
1
)
=
1
n
⁢
(
x
1
2
+
y
1
2
r
+
r
2
+
(
x
1
2
+
y
1
2
)
+
y
·
sin
⁢
ϑ
3
)
:
wherein n represents the refractive index, r represents the radius of curvature at the vertex of the convex free-form surface, ϑ3 represents a surface-type inclination angle of the convex free-form surface, which makes the light propagate in the horizontal direction through refraction, and the radius of curvature is 1-5 times the minimum spacing between the free-form surface and the sawtooth grating; for the concave free-form surface, an expression of the thickness d2 at different positions x1 and y1 on the concave free-form surface array is
d
1
(
x
1
,
y
1
)
=
1
n
⁢
(
x
1
2
+
y
1
2
r
+
r
2
-
(
x
1
2
+
y
1
2
)
+
y
1
·
sin
⁢
ϑ
3
)
:
where n represents the refractive index, r represents the radius of curvature at the vertex of the concave free-form surface, and ϑ3 represents a surface-type inclination angle of the concave free-form surface, which makes the light propagate in the horizontal direction through refraction, and the radius of curvature is 1-5 times the minimum spacing between the free-form surface and the sawtooth grating.

### Claim 2 (depends on 1)

The natural light homogenization lighting device according to claim 1, wherein an additional phase modulation φ1 of the free-form surface array to the incident light is expressed as
φ
1
=
±
π
⁡
(
x
1
2
+
y
1
2
)
λ
⁢
f
-
2
⁢
π
λ
⁢
y
1
·
sin
⁢
θ
1
,
wherein ϑ1 represents the incident angle of natural light on the free-form surface, λ represents the central wavelength of the incident light, f represents the equivalent focal length of the free-form surface, x1 and y1 are the positions of the incident wavefront of the free-form surface array, while an additional phase modulation φ2 of the sawtooth surface array to the incident natural light is expressed as
φ
2
=
-
2
⁢
π
λ
⁢
y
2
·
sin
⁢
ϑ
2
,
wherein y2 represents the position of the incident wavefront of the sawtooth surface array, and ϑ2 represents the incident angle of incident natural light on the sawtooth surface.

### Claim 3 (depends on 1)

The natural light homogenization lighting device according to claim 1, wherein an inclination angle of the sawtooth in the sawtooth surface array is in a range of 20°-70°.

### Claim 4 (depends on 1)

The natural light homogenization lighting device according to claim 1, wherein both the front surface array and the real surface array are in the form of square full-aperture arrays with a filling rate above 95%.

### Claim 5 (depends on 1)

A method of using the natural light homogenization lighting device of claim 1, comprising:
collecting light by the free-form surface array, and transmitting the light to the sawtooth surface array through the intermediate medium; and
deflecting the light with the sawtooth surface array to the indoor space after the light is refracted by the inclined surface.