A solar-powered lighting system includes a substrate, wherein at least one solar chip is disposed on one lateral side of the substrate, and at least one light source is disposed on one lateral side of the substrate. Solar light enters the substrate and propagates therein. Solar light energy is collected by the at least one solar chip which transforms the solar light energy into electrical power for the at least one light source to emit light to the substrate, before propagating therein and leaving the substrate.

BACKGROUND

1. Field of the Invention

The invention relates to a multifunction solar-powered lighting system, and in particular relates to a multifunction solar-powered lighting system, wherein solar light is guided to solar chips by a substrate to generate electrical power which is provided to a light source to emit light to the substrate.

2. Description of the Related Art

A conventional solar-powered signboard is shown inFIG. 1. A solar chip module7is disposed above the signboard5. During the day, solar light enters the solar board7to generate electrical power. The electrical power is provided to a light source9at night. In such a structure, however, the solar chip module7and the signboard5must be separated, which may hinder design and appearance of the signboard.

SUMMARY

An embodiment of a solar-powered lighting system of the invention comprises a substrate, wherein at least one solar chip disposed on one lateral side of the substrate, and at least one light source disposed on one lateral side of the substrate. Solar light enters the substrate, and is propagated therein, so that solar light energy may be collected by the at least one solar chip to transform the solar light energy into electrical power for the at least one light source to emit light to enter the substrate, propagate therein and leave the substrate.

Preferably, the at least one light source comprises at least one light emitting diode.

Preferably, the substrate comprises at least one light diffusion layer and a plurality of light guiding layers adjacent to the light diffusion layer. Solar light enters the substrate and is diffused by the light diffusion layer. The diffused solar light is reflected by an interface of the light diffusion layer and the light guiding layer to be collected by the at least one solar chip. A portion of the solar light enters the light guiding layers and is reflected by the interface of the light guiding layers, and the reflected light is collected by the at least one solar chip. The light emitted from the light source is emitted to the substrate and is guided by the light diffusion layer and the light guiding layers to leave the substrate.

Preferably, the light diffusion layer has a haze of 5˜99.

The light guiding layers are preferably made of acrylic material, polycarbonate, polyethylene terephthalate, polyurethane, polyimide, silicon resin or glass.

The light diffusion layer is preferably made of acrylic material, polycarbonate, polyethylene terephthalate, polyurethane, polyimide or silicon resin.

Preferably, the light diffusion layer comprises light scattering particles.

Preferably, the light diffusion layer comprises a mixed material of two materials with different index of refractions.

Preferably, the light diffusion layer is an optical composite structure.

The solar-powered lighting system of the invention further comprises a power accumulator connected to the at least one solar chip and the at least one light source. The electrical power generated by the at least one solar chip is saved in the power accumulator, and the saved electrical power is provided to the at least one light source.

The substrate has a first surface and a second surface opposite to the first surface, and solar light passes through the first surface to enter the substrate and the emitted light from the at least one light source passes through the first surface to leave the substrate.

The solar-powered lighting system of the invention further comprises a pattern layer disposed in the substrate, on the first surface of the substrate or on the second surface of the substrate, wherein the light from the at least one light source is emitted to the pattern layer, before leaving the substrate.

DETAILED DESCRIPTION OF INVENTION

Referring toFIGS. 2a,2b,3aand3b, a solar-powered lighting system comprises a substrate100which has a multi-layer structure. The detailed structure of the substrate100is described in the following paragraphs.

InFIGS. 2aand2b, three solar chips70are disposed on three adjacent lateral surface of the substrate100. The solar chips70are serially connected and connected to a power accumulator90. A light source80is disposed on the other lateral surface of the substrate100. The light source80is a light emitting diode in this embodiment.

When the substrate100is disposed outdoors as a signboard, during the day, solar light enters the substrate100, and propagates in the substrate100having the multi-layer structure, so that solar light energy may be collected by the solar chips70. Solar light energy is transformed into electrical power which is saved in a power accumulator90connected to the at least one light source80. At night, the power accumulator90provides electrical power for the at least one light source80to emit light. The light from the at least one light source80enters the substrate100and is emitted to a pattern or text (not shown) in or on the substrate100, and then is guided by the multi-layer structure of the substrate100to leave the substrate100, which makes the pattern or text visible at night.

Referring toFIGS. 3aand3b, four solar chips70are disposed on four lateral surface of the substrate100. Light sources80(light emitting diodes) are joined to the at least one solar chips70which are serially connected to a power accumulator90. The at least one solar chips70can be arranged in one row or two rows. If the capacity of the accumulator90is small or the area of the substrate100is small, only one row of solar chips70is needed. Solar light enters the substrate100, and propagates in the substrate100, so that solar light energy may be collected by the solar chips70. Solar light energy is transformed into electrical power which is saved in a power accumulator90connected to the light source80. At night, the power accumulator90provides electrical power for the light source80to emit light. The light from the light source80enters the substrate100and is emitted to a pattern or text (not shown) in or on the substrate100, and then is guided by the multi-layer structure of the substrate100to leave the substrate100, which makes the pattern or text visible at night.

Referring toFIG. 4, the solar-powered lighting system comprises a substrate100, wherein solar chips70are disposed on one lateral surface of the substrate100, and light sources80are disposed on another lateral surface of the substrate100. The substrate100comprises a first surface101and a second surface102opposite to the first surface101. Solar light passes through the first surface101to enter the substrate100. Light from the at least one light source80also passes through the first surface101to leave the substrate100. The lateral surfaces, on which the solar chips70and light sources80are respectively disposed, are perpendicular to the first and second surfaces101and102.

In this embodiment, a pattern layer50is disposed on the second surface102. A desired pattern or text is formed on the pattern layer50. Light from the light source80is emitted to the pattern layer50and is reflected by the pattern layer50to make the pattern or text visible. Although the pattern layer50is disposed on the second surface102in this embodiment, the pattern layer50may also be disposed on the first surface101or in the substrate100. When the pattern layer50is disposed on the first surface101or in the substrate100, the pattern or text of the pattern layer50covers a portion of the first surface101to allow solar light to enter the substrate100.

A detailed structure of the substrate100will now be described. The substrate100comprises a light diffusion layer10and light guiding layers20,30and40. Solar light L enters the light diffusion layer10.FIG. 2depicts a more detailed structure of the light diffusion layer10. Light scattering particles12are distributed in the light diffusion layer10. When solar light L enters the light diffusion layer10, solar light is scattered by the light scattering particles12. The scattered light is reflected by the interface of the light diffusion layer10so that solar light energy may be collected by the solar chips70. The particles12are preferably transparent but have different index of refractions from the material of the light diffusion layer10.

A portion of the solar light L penetrates the light diffusion layer10to enter the light guiding layer20as shown inFIG. 3. Since the index of refraction of the light diffusion layer10is different from the light guiding layers20,30and40, the solar light is refracted when the solar light enters the light guiding layer20, and the refracted light is reflected by the interface of the light guiding layer20so that solar light energy may be collected by the solar chips70.

The light guiding layers20,30and40are made of acrylic material, polycarbonate, polyethylene terephthalate, polyurethane, polyimide, silicon resin or glass. The light diffusion layer is made of acrylic material, polycarbonate, polyethylene terephthalate, polyurethane, polyimide or silicon resin.

The solar chips can be III-V column solar chips, single crystal silicon solar chips, poly crystal silicon solar chips or CIGS solar chips.

The solar-powered lighting system of the invention has many applications, some of which are illustrated in Table 1.

A suitable application for high haze substrates may be warning devices, whereas a suitable application for low haze substrates may be planar light sources or flat display devices.

FIGS. 7aand7billustrate the solar-powered lighting system of the invention being applied to a signboard.FIG. 7aillustrates the light source being turned off;FIG. 7billustrates the light source being turned on. The substrate comprises light diffusion plates having a haze of 31, a length of 445 mm, a width of 235 mm, a thickness of 3 mm and two glass plates with a thickness of 5 mm. Sixteen solar chips and eight LEDs with 0.1 W of power are disposed around the substrate. The electrical power generated by the solar-powered lighting system is 1.14 W. It is noticed, that the pattern layer (pattern and text) is formed in the first surface.

FIGS. 8aand8billustrate the solar-powered lighting system of the invention being applied to a traffic sign.FIG. 8aillustrates the light source being turned off;FIG. 8billustrates the light source being turned on. The substrate comprises a PC light diffusion plate having a haze of 41, a length of 95 mm, a width of 95 mm, a thickness of 3 mm and two glass plates with a thickness of 5 mm. Eight solar chips and four LEDs with 0.05 W of power are disposed around the substrate. The electrical power generated by the solar-powered lighting system is 0.16 W. It is noted, that the pattern layer (pattern and text) is formed in the first surface.

FIGS. 9aand9billustrate the solar-powered lighting system of the invention being applied to an electronic book.FIG. 9aillustrates the light source being turned off;FIG. 9billustrates the light source being turned on. The substrate comprises a PC light diffusion plate having a haze of 14, a length of 155 mm, a width of 85 mm, a thickness of 3 mm and two glass plates with a thickness of 5 mm. Eight solar chips and eight LEDs with 0.05 W of power are disposed around the substrate. The electrical power generated by the solar-powered lighting system is 0.04 W. It is noted that the pattern layer (pattern and text) is formed in the first surface.