Projection displaying apparatus, image projecting system, and optical system for projection displaying apparatus

A projection displaying apparatus for projecting on a projection plane an image displayed on a reflection displaying device using light emitted from a light source, said projection displaying apparatus comprising:

• a wind feeding portion for feeding a cooling wind to a light-incident side of a polarization plate disposed on an optical path from the light source to the reflection displaying device;
• a wind guiding portion for guiding the cooling wind such that the cooling wind can be blown on the polarization plate slantingly relative to a light-incident face of the polarization plate;
• and
• a dichroic mirror for emitting light in a first wavelength range out of incident light toward a direction approximately parallel to a direction of the incident light, and emitting light in a second wavelength range out of the incident tight toward a direction approximately perpendicular to the direction of the incident light,
• wherein the polarization plate includes a first polarization plate provided on an optical path of the light in the first wavelength range, and a second polarization plate provided on an optical path of the light in the second wavelength range, and the wind feeding portion includes a first wind feeding portion for feeding a cooling wind to a light-incident side of the first polarization plate, and a second wind feeding portion for feeding a cooling wind to a light-incident side of the second polarization plate, and
• wherein the amount of the cooling wind fed to the light-incident side of the polarization plate provided on the optical path of light in a larger wavelength range out of the first wavelength range and the second wavelength range is set larger than the amount of the cooling wind fed to the light-incident side of the polarization plate provided on the optical path of light in a smaller wavelength range out of the first wavelength range and the second wavelength range.

A projection displaying apparatus for projecting on a projection plane an image displayed on a reflection displaying device using light emitted from a light source, said projection displaying apparatus comprising:

• a wind feeding portion for feeding a cooling wind to a light-incident side of a polarization plate disposed on an optical path from the light source to the reflection displaying device;
• a wind guiding portion for guiding the cooling wind such that the cooling wind can be blown on the polarization plate slantingly relative to a light-incident face of the polarization plate;
• and
• a dichroic mirror for emitting light in a first wavelength range out of incident light toward a direction approximately parallel to a direction of the incident light, and emitting light in a second wavelength range out of the incident light toward a direction approximately perpendicular to the direction of the incident light,
• wherein the polarization plate includes a first polarization plate provided on an optical path of the light in the first wavelength range, and a second polarization plate provided on an optical path of the light in the second wavelength range, and the wind feeding portion includes a first wind feeding portion for feeding a cooling wind to a light-incident side of the first polarization plate, and a second wind feeding portion for feeding a cooling wind to a light-incident side of the second polarization plate, and
• wherein the wind feeding portion includes a cooling wind generator for generating a cooling wind, a first blast port for blowing the cooling wind on the light-incident side of the first polarization plate, and a second blast port for blowing the cooling wind on the light-incident side of the second polarization plate, and an area of the blast port for blowing the cooling wind on the light-incident side of the polarization plate provided on the optical path of light in a larger wavelength range out of the first wavelength range and the second wavelength range is set larger than an area of the blast port for blowing the cooling wind on the light-incident side of the polarization plate provided on the optical path of light in a smaller wavelength range out of the first wavelength range and the second wavelength range.