Light source apparatus

• US 5,695,268 A
• Filed: 03/19/1996
• Issued: 12/09/1997
• Est. Priority Date: 06/12/1995
• Status: Expired due to Fees

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Hagiwara, Tsuneyuki
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US08/618,373
• Time in Patent Office: 630 Days
• Field of Search: 349/9, 359/487, 359/490, 359/494-497, 362/19, 362/300, 362/293, 362/343, 362/346
• US Class Current: 362/19
• CPC Class Codes: F21V 9/14 for producing polarised light
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/13355 Polarising beam splitters [PBS]
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one

Abstract

A light source apparatus for emitting rectilinear polarized light beams includes a light source unit, a polarizing filter unit for transmitting a first rectilinear polarized component among the light beams emitted from the light source unit but reflecting a second rectilinear polarized component and a light reflecting member for reflecting the second rectilinear polarized component in a direction of the polarizing filter unit and converting a direction of a polarization plane of the reflected second rectilinear polarized component into a direction of a polarization plane of the first rectilinear polarized component.

Claims

1. A light source apparatus for emitting rectilinear polarized light beams, comprising:

a light source;

a polarizing filter device which transmits a first rectilinear polarized component of light emitted from said light source but reflects a second rectilinear polarized component of light emitted from said light source; and

a light reflecting device which reflects light of said second rectilinear polarized component toward said polarizing filter device and converts a direction of a polarization plane of that light into a direction of a polarization plane of said first rectilinear polarized component,

wherein said light reflecting device includes a combination of roof mirrors each having a vertical angle of approximately 90°

, and respective crest and trough lines of the combination of said roof mirrors are disposed to make an angle of approximately 45°

to a polarizing direction of incident light of said second rectilinear polarized component.

2. A light source apparatus according to claim 1, wherein said polarizing filter device includes a combination of polarizing beam splitters.

3. A light source apparatus according to claim 1, wherein said light source is disposed between said polarizing filter device and said light reflecting device, and near an end of at least one of said polarizing filter device and said light reflecting device, and

said light reflecting device is disposed to be skewed relative to said polarizing filter device such that a distance therebetween is minimum at an opposite end of said at least one of said polarizing filter device and said light reflecting device.

4. A light source apparatus according to claim 1, wherein said light source is disposed between said light reflecting device and said polarizing filter device.