Secondary lens, photovoltaic cell mounting body, concentrating photovoltaic power generation unit, and concentrating photovoltaic power generation module

A secondary lens used in a concentrating photovoltaic power generation module which applies light concentrated by a concentrating lens to a photovoltaic cell, the secondary lens comprising:

• a first face which opposes the concentrating lens and on which a concentrated light beam output from the concentrating lens is incident;
• and
• a second face which opposes the photovoltaic cell and from which the concentrated light beam output from the concentrating lens is output, the secondary lens guiding incident light to the photovoltaic cell through an optical refractive face provided on the first face, wherein
• a cross-sectional area of the first face in a direction perpendicular to an optical axis of the concentrated light beam monotonically increases as the cross-sectional area approaches from a side of the first face closer to the concentrating lens to a side of the first face closer to the photovoltaic cell, and
• at least one point of inflection at which an angle of inclination of the first face with respect to a plane perpendicular to the optical axis decreases as the angle of inclination approaches from the side of the first face closer to the concentrating lens to the side of the first face closer to the photovoltaic cell is provided.