Light-Concentrating Mechanism, Photovoltaic Power Generation Device, Window Structure, and Glass Window

Abstract

A light-concentrating mechanism comprises an angle-selective reflection means that reflects light having an incident angle of at least a first threshold angle and transmits at least some of the light having an incident angle smaller than the first threshold angle, and an angle-increase reflection means that reflects incident light at an angle greater than the incident angle of said light, the two means being arranged to have a gap therebetween. The angle-increase reflection means reflects, at an angle equal to or greater than the first threshold angle, at least some of the light transmitted by the angle-selective reflection means, and the angle-selective reflection means reflects the light reflected by the angle-increase reflection means and has an angle that is equal to or greater than the first threshold angle. Light is propagated and concentrated by the gap between the angle-selective reflection means and the angle-increase reflection means.

What is claimed is: 
     
         1 . A light-concentrating mechanism, comprising:
 an angle-selective reflector comprising an angle-selective property; and   an angle-increasing reflector comprising an angle-increasing property and a deflecting property, the angle-selective reflector and the angle-increasing reflector being disposed with a gap therebetween, wherein:   the angle-selective reflector is configured to reflect light having an incidence angle equal to or larger than a first threshold angle and to transmit at least a portion of light having an incidence angle smaller than the first threshold angle;   the angle-increasing reflector including a reflective holographic optical element configured to reflect at least a portion of an incident light that passes through the angle-selective reflector at a reflection angle larger than an incidence angle thereof, while deflecting a traveling direction of light reflected by the angle-increasing reflector, wherein the reflection angle is equal to or larger than the first threshold angle; and   the angle-selective reflector and the angle-increasing reflector are configured to propagate and maintain the light within the gap between the angle-selective reflector and the angle-increasing reflector, thereby concentrating the light within the gap.   
     
     
         2 . The light-concentrating mechanism of  claim 1 , wherein the angle-selective reflector is provided on a front surface of glass or resin, and the angle-increasing reflector is provided on a rear surface of the glass or resin, wherein light is concentrated on an end of the glass or resin as light propagates in the gap between the angle-selective reflector and the angle-increasing reflector. 
     
     
         3 . The light-concentrating mechanism of  claim 2 , wherein the front surface of the glass or resin comprises a boundary surface defining the angle selective reflector. 
     
     
         4 . The light-concentrating mechanism of  claim 1 , wherein the angle-increasing reflector comprises an angle-selective property configured to reflect light incident at an incidence angle equal to or larger than a second threshold angle and transmit light incident at an incidence angle smaller than the second threshold angle. 
     
     
         5 . The light-concentrating mechanism of  claim 1 , wherein the angle-increasing reflector comprises a wavelength-selective property configured to transmit light in a predetermined wavelength range. 
     
     
         6 . A photovoltaic power generation device comprising:
 the light-concentrating mechanism of  claim 1 ; and   a photovoltaic cell that receives light concentrated by the light-concentrating mechanism to generate electricity.   
     
     
         7 . A window structure having a light-concentrating mechanism, comprising:
 a glass or resin; and   an angle-increasing reflector comprises an angle-increasing property and a deflecting property provided on a rear surface of the glass or resin, wherein:   the angle-increasing reflector includes a reflective holographic optical element configured to reflect at least a portion of an incident light that passes through the glass or resin at a reflection angle larger than an incidence angle thereof while deflecting a traveling direction of light reflected by the angle-increasing reflector, wherein the reflection angle is equal to or larger than a critical angle of the glass or resin; and   a front surface of the glass or resin reflects a light reflected by the angle-increasing reflector; and   the angle-increasing reflector and the front surface are configured to propagate and maintain the light within the gap between the angle-selective reflector and the front surface, thereby concentrating the light within the gap.   
     
     
         8 . The window structure of  claim 7 , wherein a photovoltaic cell that receives light concentrated by the light-concentrating mechanism to generate electricity.