Diffraction lens element and lighting system using the lens element

• US 20030123159A1
• Filed: 11/08/2002
• Published: 07/03/2003
• Est. Priority Date: 03/09/2001
• Status: Abandoned Application

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Morita, Masayuki, Miyazaki, Kanto
• Application Number:
  US10/275,867
• Publication Number:
  US 20030123159A1
• Time in Patent Office: Days
• US Class Current: 359/742
• CPC Class Codes: G02B 21/06 Means for illuminating specimens
• CPC Class Codes: G02B 21/16 adapted for ultraviolet illumination ; Fluorescence microscopes G02B21/0076 takes precedence
• CPC Class Codes: G02B 27/425 in illumination systems mask illumination systems in photolithographic systems G03F7/70158
• CPC Class Codes: G02B 27/48 Laser speckle optics
• CPC Class Codes: G02B 5/1842 Gratings for image generation G02B5/1847 takes precedence
• CPC Class Codes: G02B 5/1857 using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams
• CPC Class Codes: G02B 5/1876 Diffractive Fresnel lenses; Zone plates; Kinoforms G02B5/1842, G02B5/1847 take precedence; optical systems having diffractive correction means G02B27/0037; Fresnel lenses operating by refraction G02B3/08

Abstract

By proposing a diffractive optical element having optical functions of a random phase plate and a lens array in combination, and an illumination apparatus employing this lens element, reduction of speckles, and improvements in energy efficiency and light utilization efficiency are achieved simultaneously.

In a transparent base material, by individually assigning or superimposing an amount of variation in accordance with a random number onto each of the depths of recessed portions constituting steps equivalent in value to a lens or a lens array, recessed portions having irregular phase variations are formed and a diffractive lens element (6) is made. Also, in an illumination apparatus employing this diffractive lens element and a laser light source, in order to obtain a uniform illumination light from which speckles are eliminated, the diffractive lens element (6) is rotated by a rotating means.

Claims

1. A diffractive lens element in which a cross-sectional form is formed in a step shape by forming multiple recessed portions having different depths with respect to a transparent base material, and has optical functions of one lens or a plurality of lenses and a random phase plate in combination, said diffractive lens element characterized in that recessed portions having irregular phase variations are formed by adding or superimposing a variation amount in accordance with a random number onto depths of recessed portions constituting steps which are equivalent in value to a lens or a lens array.

2. An illumination apparatus for obtaining a uniform illumination light from which speckles are eliminated using the diffractive lens element according to claim 1, characterized in that said illumination apparatus is provided with a laser light source and rotating means for rotating said diffractive lens element.

3. The illumination apparatus according to claim 2, said illumination apparatus characterized in that a light from the laser light source is irradiated on the diffractive lens element via a condenser lens after being propagated by a optical fiber.