The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 2009
Filed:
Oct. 06, 2006
Atsushi Okuyama, Tokorozawa, JP;
Takashi Sudo, Utsunomiya, JP;
Atsushi Okuyama, Tokorozawa, JP;
Takashi Sudo, Utsunomiya, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
An illumination optical system is disclosed which capable of uniformly illuminating a surface to be illuminated. The illumination optical system comprises a polarization conversion element which converts a luminous flux from a light source into a luminous flux having a certain polarization direction, a polarization beam splitter which splits the luminous flux from the polarization conversion element, and a phase plate which gives a phase difference to the luminous flux from the polarization beam splitter. The system illuminates the surface with the luminous flux from the phase plate and satisfies the conditions θx<θy and 0°<φy<θy. θx and θy represent the maximum incident angles onto the surface in the x and y directions, and φy represents an incident angle onto the phase plate at which the phase difference at a principal wavelength of the luminous flux that passes through the phase plate is 90 degrees.