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Alignment of optical element and solar cell

Alignment of optical element and solar cell description/claims

The present application claims priority to U.S. Provisional Patent Application Ser. No. 60/899,150, filed on Feb. 2, 2007 and entitled “Concentrated Photovoltaic Energy Designs”, the contents of which are incorporated herein by reference for all purposes.

1. Field

Some embodiments generally relate to the conversion of solar radiation to electrical energy. More specifically, embodiments may relate to systems to improve the efficiency of manufacture and/or operation of solar radiation collectors.

2. Brief Description

A concentrating solar radiation collector may convert received photons (i.e., sunlight) into a concentrated beam of photons and direct the concentrated beam onto a small photovoltaic cell. The cell, in turn, converts the photons of the concentrated beam into electrical current.

U.S. Patent Application Publication No. 2006/0231133 describes several types of concentrating solar collectors. As described therein, a photovoltaic cell may be coupled to concentrating optics and electrical contacts of a solar collector using a clear adhesive (e.g., silicone) and wirebonds, respectively. Alternatively, photovoltaic cell may be incorporated into a surface mount package or a front-side mounting package and connected to optics using clear underfill material and to electrical contacts using soldered interconnects.

A photon-receiving surface of a photovoltaic cell must be aligned precisely with respect to the optical path of the solar collector. The alignment is achieved by mechanical means such as industrial pick and place machines and will likely require local fiducial marks to be placed on the optics. The alignment accuracy depends on the mechanical accuracy of the pick and place machine and the placement accuracy of the local fiducial marks.

The above-described alignment techniques can be inefficient and expensive. For example, accurate alignment (e.g., in the 10-12 micron range) will likely require reduction of the pick and place speed. The combination of reduced pick and place speed and the requirement of local fiducials will slow down the production speed and result in higher production cost.

What is needed is a system to couple an optically-active semiconductor device to an optical element that addresses one or more of the foregoing and/or other existing concerns.

To address at least the foregoing, some aspects provide a system, an apparatus, a method and/or process steps to place a solder bump in contact with an electrical contact of a solar cell, place the solder bump in contact with an electrical contact of an optical element, and melt the solder bump to couple the electrical contact of the solar cell to the electrical contact of the optical element. Some embodiments may melt the solder bump in order to align an optically active area of the solar cell with a light-emitting interface of the optical element.

In some aspects, an apparatus includes a solar cell comprising a first electrical contact, the solar cell to generate charge carriers in response to received photons, an optical element comprising a second electrical contact, and a solder bump in contact with the first electrical contact and the second electrical contact. The solar cell may comprise an optically-active area, the optical element may comprise a light-emitting interface, and the optically-active area may be aligned with the light-emitting interface.

Further to the foregoing aspect, the solar cell may include a semiconductor substrate comprising a majority of a first type of charge carrier, a first semiconductor portion comprising a majority of a second type of charge carrier, and a semiconductor layer disposed between the semiconductor substrate and the first semiconductor portion to generate charge carriers of the first type and of the second type in response to received photons. A third electrical contact may be in contact with the semiconductor substrate and may receive charge carriers of the second type generated by the semiconductor layer. Moreover, the first semiconductor portion may be disposed between the first electrical contact and the semiconductor layer.

The claims are not limited to the disclosed embodiments, however, as those in the art can readily adapt the description herein to create other embodiments and applications.

The construction and usage of embodiments will become readily apparent from consideration of the following specification as illustrated in the accompanying drawings, in which like reference numerals designate like parts.

• Provisional Patent
• Utility Patent

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