# US 9,040,808 B2 · Light-guide solar panel and method of fabrication thereof

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- Number: US 9,040,808 B2
- Document ID: US9040808B2
- Status: Granted
- Kind: B2
- Application number: 12/705,415
- Filed: 2010-02-12
- Published: 2011-01-20
- Granted: 2015-05-26
- Earliest claimed: 2007-05-01
- Assignees: Morgan Solar Inc.
- Applicants: John Paul Morgan; Philip M. Chang; Stefan H. S. Myrskog
- Inventors: John Paul Morgan; Philip M. Chang; Stefan H. S. Myrskog
- Web page: https://patentgrep.com/patent/US9040808B2

## CPC

- H10F 77/488: {Reflecting light-concentrating means, e.g. parabolic mirrors or concentrators using total internal reflection}
- G02B 7/183: specially adapted for very large mirrors, e.g. for astronomy, {or solar concentrators}
- H02S 40/22: Light-reflecting or light-concentrating means (directly associated with the PV cell or integrated with the PV cell H10F77/42)
- H10D 48/34: Bipolar devices
- H10F 71/00: Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00)
- H10F 77/63: Arrangements for cooling directly associated or integrated with photovoltaic cells, e.g. heat sinks directly associated with the photovoltaic cells or integrated Peltier elements for active cooling
- H02S 20/00: Supporting structures for PV modules
- Y02E 10/52: PV systems with concentrators
- H10F: INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H02S: GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES (obtaining electrical energy from radioactive sources G21H1/12; light sensitive inorganic semiconductor devices H10F; light sensitive organic semiconductor devices H10K30/00; thermoelectric devices H10N10/00; pyroelectric devices H10N15/00)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

The present invention is that of a solar energy system that uses a light-guide solar panel (LGSP) to trap light inside a dielectric or other transparent panel and propagates the light to one of the panel edges for harvesting by a solar energy collector such as a photovoltaic cell. This allows for very thin modules whose thickness is comparable to the height of the solar energy collector. This eliminates eliminating the depth requirements inherent in traditional concentrated photovoltaic solar energy systems. A light guide solar panel has a deflecting layer, a light guide layer and a solar cell in optical communication with the light guide layer. The deflecting layer receives light at a first surface and inputs the light into the light guide layer. The light guide layer propagates the light to the solar cell, which is aligned generally parallel to the input surface.

## Claims

### Claim 1

A solar concentrator comprising:
a light-insertion layer that is transmissive to sunlight, the light-insertion layer having a plurality of optical deflecting elements for redirecting light impinging thereon into an optical waveguide slab via total internal reflection;
the optical waveguide slab being transmissive to sunlight and having:
a first reflective surface;
a plurality of reflectors opposite the first reflective surface and proximate the light-insertion layer; and
an output surface;
the optical waveguide slab being substantially wedge-shaped in cross-section between the output surface and an upstream edge of the optical waveguide slab, with the wedge opening toward the output surface,
the optical waveguide slab being optically coupled to the optical deflecting elements of the light-insertion layer to receive light therefrom,
the optical deflecting elements, the first reflective surface and the plurality of reflectors being positioned and arranged such that received light from the light insertion layer is guided through the optical waveguide slab towards the output surface via reflections between the first reflective surface and the plurality of reflectors, and
the optical deflecting elements and the reflectors being arranged along arcs of concentric circles; and
a secondary optical element that is transmissive to sunlight, the secondary optical element having:
an optical entry surface optically coupled to the output surface to receive light therefrom;
an optical exit surface; and
at least one secondary reflective surface positioned to redirect at least a portion of the light received through the optical entry surface, to the optical exit surface;
the solar concentrator having a substantially planar shape.

### Claim 2 (depends on 1)

The solar concentrator of claim 1, wherein:
the optical waveguide slab comprises a plurality of waveguide entry surfaces through which light is received from the light-insertion layer;
each waveguide entry surface is located adjacent to and between the reflectors;
each of the optical deflecting elements is associated with and redirects light toward one of the waveguide entry surfaces, and
the first reflective surface is opposite the plurality of waveguide entry surfaces.

### Claim 3 (depends on 1)

The solar concentrator of claim 1 wherein the optical deflecting elements and the reflectors have rotational symmetry about a common central axis of rotational symmetry.

### Claim 4 (depends on 3)

The solar concentrator of claim 3 wherein the optical deflecting elements and the reflectors are arranged along concentric circles and wherein the optical entry surface of the secondary optical element is an annular ring centered about the common central axis of rotational symmetry.

### Claim 5 (depends on 2)

The solar concentrator of claim 2 wherein the plurality of deflecting elements are arranged in a plurality of functional units, each functional unit comprising one or more of the plurality of deflecting elements and each functional unit being associated with one of the plurality of waveguide entry surfaces, and wherein at least one of the deflecting elements of each functional unit is a reflective surface.

### Claim 6 (depends on 2)

The solar concentrator of claim 2 wherein each waveguide entry surface is part of a ridge.

### Claim 7 (depends on 3)

The solar concentrator of claim 3 wherein:
the secondary optical element has rotational symmetry about the common central axis of rotational symmetry;
the optical entry surface of the secondary optical element is for receiving light travelling substantially toward the common central axis of rotational symmetry; and
the optical exit surface of the secondary optical element is generally parallel to the plane of the solar concentrator.

### Claim 8 (depends on 7)

The solar concentrator of claim 7, wherein in operation, light received by the secondary optical element is guided by total internal reflection.

### Claim 9 (depends on 1)

The solar concentrator of claim 1, wherein the secondary reflective surface comprises at least one first curved portion.

### Claim 10 (depends on 9)

The solar concentrator of claim 9, wherein the at least one first curved portion comprises a mirror coating to redirect the received light toward the optical exit surface of the secondary optical element.

### Claim 11 (depends on 1)

The solar concentrator of claim 1, wherein the solar concentrator is of a planar shape that is tileable.

### Claim 12 (depends on 11)

The solar concentrator of claim 11, wherein the planar shape of the solar concentrator is square.

### Claim 13 (depends on 1)

The solar concentrator of claim 1 wherein the surface of the optical waveguide slab through which the optical waveguide slab is optically coupled to the light-insertion layer comprises an anti-reflection texture for preventing back reflections.

### Claim 14 (depends on 1)

The solar concentrator of claim 1, wherein the secondary optical element is made of a thermally insulating material.

### Claim 15 (depends on 1)

A light-guide solar panel module comprising the solar concentrator of claim 1 and at least one solar energy collector optically coupled to the optical exit surface.

### Claim 16 (depends on 15)

The light-guide solar panel module of claim 15 wherein the at least one solar energy collector is at least one photovoltaic cell mounted on a circuit board and the light-guide solar panel module further comprises a low index film mask between the circuit board, and the optical waveguide slab and the secondary optic for preventing light from striking areas of the printed circuit board other than the at least one photovoltaic cell.

### Claim 17 (depends on 15)

The light-guide solar panel module of claim 15 wherein the at least one solar energy collector is at least one photovoltaic cell mounted on a circuit board and the light-guide solar panel module further comprises:
a tray for supporting the light-insertion layer and the optical waveguide slab; and
a heat sink in thermal communication with the at least one photovoltaic cell.

### Claim 18 (depends on 15)

The light-guide solar panel module of claim 15 wherein each of the at least one solar energy collector is a photovoltaic cell and the secondary reflective surface of the secondary optical element comprises four quadrants, each quadrant having a curved portion and tapering toward a common point, and each quadrant for focusing the light impinging on that quadrant onto an associated photovoltaic cell that is distinct from the photovoltaic cells associated with the other quadrants.

### Claim 19 (depends on 18)

A light-guide solar panel assembly comprising a plurality of electrically interconnected optical subassemblies affixed to a heat sink, each optical subassembly comprising:
a light-guide solar panel module of claim 18 wherein each of the at least one solar energy collector is a photovoltaic cell mounted on a circuit board, and
a tray supporting the light-insertion layer, the optical waveguide slab, the secondary optic and the circuit board, the tray comprising a bottom wall and an aperture through the bottom wall, wherein the at least one photovoltaic cell is optically connected to the secondary optic through the aperture of the tray, and
wherein the circuit boards of the plurality of optical subassemblies are electrically interconnected in series, and wherein the photovoltaic cells are in thermal communication with the heat sink.

### Claim 20 (depends on 19)

The light-guide solar panel assembly of claim 19 wherein the trays are integrally formed such that the plurality of light-guide solar panel modules are supported by a single assembly tray, and wherein the light-insertion layers are integrally formed.