Nonimaging Optics

3 SOME DESIGNS OF IMAGE-FORMING CONCENTRATORS

3.1 INTRODUCTION

In this chapter we examine image-forming concentrators of conventional form—paraboloidal mirrors, lenses of short focal length, and so forth—and estimate their performance. Then we shall show how the departure from ideal performance suggests a principle for the design of nonimaging concentrators—the “edge-ray principle,” as we shall call it.

3.2 SOME GENERAL PROPERTIES OF IDEAL IMAGE-FORMING CONCENTRATORS

In order to fix our ideas we use the solar energy application to describe the mode of action of our systems. The simplest hypothetical image-forming concentrator would then function as in Figure 3.1. The rays are coded to indicate that rays from one direction from the sun are ...