Kuraray Co., Ltd.

Makoto Toyohara

Youji Ono

Ichiro Matsuzaki

Kazunori Hirose

A photovoltaic unit can minimally reduce a displacement of focus positions from solar cells and prevent a decrease in power generation efficiency even if elastic behaviors of a Fresnel lens sheet and a base plate on which solar cells are arranged due to changes in temperature and humidity are different. The photovoltaic unit includes an integrated multiple Fresnel lens sheet and a base plate on which solar cells are arranged adjacent to the focus positions of individual Fresnel lenses. The multiple Fresnel lens sheet is fixed to the base plate by a lens sheet fixing element at a lens sheet fixing portion adjacent to the center of gravity of the sheet.

Photovoltaic equipment

A design method for an optical sheet for solar concentration and an optical sheet for solar concentration obtained by means of the design method are disclosed. The design method is characterized in that, for a resin optical sheet for solar concentration containing an ultraviolet absorber in a base material thereof, an amount of the ultraviolet absorber to be contained in the base material is determined such that: in an accelerated degradation test by means of a metal-halide-lamp weathering test (device specification: JTM G 01:2000, Japan Testing Machinery Association), decrease in average transmittance in a wavelength range of 400 nm to 1850 nm after testing for an irradiation time Tsatisfies the following equation (1)&#x3c4;(0)+&#x3c4;()&#x3e;&#x3c4;(0)+&#x3c4;()&#x2003;&#x2003;(1)and that decrease in transmittance at each of wavelengths in the wavelength range from a corresponding initial value after testing for the irradiation time Tis not greater than 10%. Tis the accelerated test time required corresponding to the actual location of use. The optical sheet of the present invention is capable of efficiently concentrating light without decrease in transmittance while being used for a long time in an environment with a large amount of ultraviolet radiation.

Fresnel lens sheet for solar concentration and design method therefor

A Fresnel lens sheet which is bright due to a small light quantity loss, is restricted in speckles and ghosts, does not produce moires, and can be used in an inexpensive transmitting screen, wherein the sheet satisfies the diffusion characteristics of the following expressions (1) and (2), or the following expressions (3), (4) and (5). &#x3b3;/&#x3b1;&#x2266;2.8 (1) &#x3b6;/&#x3b1;&#x2266;6 (2), where &#x3b1; is viewing half value angle, &#x3b3; viewing 1/10 value angle, and &#x3b6; viewing 1/100 value angle. 2.0&#xb0;&#x2266;&#x3b1;&#x2266;5.5&#xb0; (3), where &#x3b1; is viewing half value angle, &#x3b3;&#x2266;12&#xb0; (4), where &#x3b3; is viewing 1/10 value angle, &#x3b6;&#x2266;18&#xb0; (5), where &#x3b6; is viewing 1/100 value angle.

Growing community of inventors

Kamisu, Japan

Makoto Toyohara