Patent ID: 6685342
Filing Date: 2004-02-03
Classification: F21V,F21Y

Abstract:
An illumination device comprising:a first prism adapted to be located in front of a flash tube, and having a first transmitting/totally-reflecting surface adapted to be opposed substantially entirely to a longitudinal direction of said flash tube so that light diverging from said flash tube at an angle smaller than a predetermined angle relative to a center axis of radiation in said illumination device which lies in the longitudinal direction of said flash tube will be transmitted and radiated forwards, and so that light diverging from said flash tube at an angle larger than the predetermined angle relative to the center axis of radiation in said illumination device will be totally reflected and laterally directed; a second prism also adapted to be located in front of said flash tube, and having a second transmitting/totally-reflecting surface adapted to be opposed substantially entirely to the longitudinal direction of said flash tube so that light diverging from said flash tube at an angle smaller than the predetermined angle relative to the center axis of radiation in said illumination device that lies in the longitudinal direction of said flash tube will be transmitted and radiated forwards, and so that light diverging from said flash tube at an angle larger than the predetermined angle relative to the center axis of radiation in said illumination device will be totally reflected and laterally directed; a reflecting member, formed to cover at least part of a periphery of said optical prism, for reflecting light that passes the periphery of said optical prism; a housing prism having: (i) an incidence surface on which light transmitted or totally reflected from said transmitting/totally-reflecting surface finally falls, and (ii) an emitting surface that radiates incident light on said incidence surface forwards, said emitting surface being exposed as a housing member; and a prism unit forming means for use in placing said first transmitting/totally-reflecting surface of said first prism and said second transmitting/totally-reflecting surface of said second prism on said incidence surface of said housing prism with a gap of a substantially uniform width between them.