JPS54119260A - Luminous flux diverging apparatus using prisms - Google Patents

Abstract

PURPOSE: To provide an apparatus which is capable of applying divergent angles to incident luminous flux by compressing the same without aberration by the use of prisms and making the divergent angles thereof readily variable with the afocal optical system using the prisms by making positive use of the divergent action thereof.

CONSTITUTION: Four prisms 1 thru 4 whose sections perpendicular to the refracting edges are all resembling are so disposed that the refracting edges are mutually parallel and become parallel to the Z-axis (direction perpendicular to the plane of the figure). These are so combined that the main optical axis directions of the luminous fluxes being emitted with respect to the luminous flux incident to the optical system align and that the incident faces of the individual prisms are perpendicular to the incident luminous flux. The luminous flux entering perpendicularly to the incident face of each prism is reflected at its exit face and at that time, the width of the luminous flux within the plane perpendicular to the refracting edge is compressed. Hence, the parallel luminous fluxes 5 incident to the prism 1 pass through all of the four prisms and the luminous fluxes 9 emitting in the same direction as the incident luminous fluxes 5 are made sheet beams. At this time, if the angle of the incident faces to the respective incident light of the prisms are changed, the rates of compression change, resulting in the changed divergent angle and this makes the width of the luminous flux variable.

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