OPTICAL INTEGRATOR OF WAVEFRONT SPLITTING TYPE AND ILLUMINATING OPTICAL DEVICE PROVIDED WITH THE OPTICAL INTEGRATOR

摘要

PROBLEM TO BE SOLVED: To provide an optical integrator of wavefront splitting type which enables to obtain a uniform illuminance distribution over almost the whole of illuminated field which is formed even when the sizes of respective micro lenses are made small and the number of wavefront splitting is set in large numbers. SOLUTION: This optical integrator of wave front splitting type has a large number of micro lenses which are arranged two-dimensionally, wavefront-splits an incident luminous flux and forms a large number of light sources. Each micro lens has a regularly hexagonal incident face which inscribes with a circle of diameter d and a regularly hexagonal emission face which inscribes with the circle of diameter d and, when the focal distance of each micro lens is f and the wavelength of the incident luminous flux isλ, the condition of (d/2)2/(λ.f)>=3.05 is satisfied.