Image display element, and image display device

(Amended) An image display apparatus comprising:

• a light source for radiating illuminating light;
• a polarization selective holographic optical device for diffracting illuminating light, said device including a plurality of each of two areas having refractive index values exhibiting respectively different incidence polarization orientation dependencies, said areas being layered sequentially alternately;
• an illuminating optical system for causing the illuminating light radiated from said light source to be incident on said polarization selective holographic optical device;
• a reflection type spatial optical modulator for modulating the polarized state of the illuminating light diffracted by said polarization selective holographic optical device;
• and
• a projection optical system for projecting the illuminating light on a screen through said reflection type spatial optical modulator and through said polarization selective holographic optical device;
• said polarization selective holographic optical device, one of two areas of which exhibits refractive index anisotropy, with the other exhibiting refractive index isotropy, being irradiated by said illuminating optical system with the illuminating light at an angle of incidence not less than 30° and less than 90° with respect to a normal line to a light receiving surface thereof for said illuminating light, said polarization selective holographic optical device diffracting a P-polarized light component or an S-polarized light component of said illuminating light to radiate the diffracted light towards said reflection type spatial optical modulator;
• said polarization selective holographic optical device exhibiting the diffraction efficiency of not higher than 10% for the polarized light component of the illuminating light incident a second time thereon after phase modulation by said reflection type spatial optical modulator, which polarized light component has a direction of polarization perpendicular to a direction of polarization of the polarized light component diffracted thereby at the time when the illuminating light is first incident thereon, whereby not less than 70% of the first-stated polarization component is transmitted through the optical device.
• said projection optical system projecting the light transmitted through said polarization selective holographic optical device on a screen.

(Amended) An image display apparatus comprising:

• a polarization selective holographic optical device for diffracting the incident light, said device including a plurality of each of two areas having refractive index values exhibiting respectively different incidence polarization orientation dependencies, said areas being layered sequentially alternately;
• color separation means for separating said illuminating light in a plurality of representing different wavelength range components;
• an illuminating optical system for causing the illuminating light separated into respective different wavelength range components to be incident on said polarization selective holographic optical device;
• a plurality of reflection type spatial optical modulators for modulating polarized states of a plurality of representing different wavelength range components of the illuminating light diffracted by said polarization selective holographic optical device;
• color synthesis means for synthesizing illuminating light portions of respective different wavelength ranges modulated by said plural reflection type spatial optical modulators;
• and
• a projection optical system for projecting the illuminating light through said color synthesis means;
• said polarization selective holographic optical device, one of two areas of which exhibits refractive index anisotropy, with the other exhibiting refractive index isotropy, being irradiated by said illuminating optical system with the illuminating light at an angle of incidence not less than 30° and less than 90° with respect to a normal line to a light receiving surface thereof for said illuminating light, said polarization selective holographic optical device diffracting a P-polarized light component or an S-polarized light component of said illuminating light to radiate the diffracted light towards said reflection type spatial optical modulator;
• said polarization selective holographic optical device exhibiting the diffraction efficiency of not higher than 10% for the polarized light component of the illuminating light incident a second time thereon after phase modulation by said reflection type spatial optical modulator, which polarized light component has a direction of polarization perpendicular to a direction of polarization of the polarized light component diffracted thereby at the time when the illuminating light is first incident thereon, whereby not less than 70% of the first-stated polarization component is transmitted through the optical device;
• said projection optical system projecting the illuminating light transmitted through said polarization selective holographic optical device and through said color synthesis means on a screen.

(Amended) An image display apparatus comprising:

• a light source for radiating illuminating light;
• a polarization selective holographic optical device for diffracting illuminating light, said device including a plurality of each of two areas having refractive index values exhibiting respectively different incidence polarization orientation dependencies, said areas being layered sequentially alternately;
• wavelength-band-based polarization separating means for separating the states of polarization of respective different first and second wavelength range components of said illuminating light as linear polarized components perpendicular to each other;
• an illuminating optical system for causing the illuminating light separated into first and second wavelength range components to be incident on said polarization selective holographic optical device;
• a first reflection type spatial optical modulator for modulating the state of polarization of the first wavelength range component of the illuminating light diffracted by the polarization selective holographic optical device;
• a second reflection type spatial optical modulator for modulating the state of polarization of the second wavelength range component of the illuminating light transmitted through the polarization selective holographic optical device;
• and
• a projection optical system for projecting the illuminating light through said reflection type spatial optical modulator on a screen;
• said polarization selective holographic optical device, one of two areas of which exhibits refractive index anisotropy, with the other exhibiting refractive index isotropy, being irradiated by said illuminating optical system with the illuminating light at an angle of incidence not less than 30° and less than 90° with respect to a normal line to a light receiving surface thereof for said illuminating light, said polarization selective holographic optical device diffracting said first wavelength range component as a P-polarized light component or an S-polarized light component to radiate the diffracted light towards said reflection type spatial optical modulator;
• said polarization selective holographic optical device exhibiting the diffraction efficiency of not higher than 10% for the polarized light component of the illuminating light incident a second time thereon after phase modulation by said reflection type spatial optical modulator, which polarized light component has a direction of polarization perpendicular to a direction of polarization of the polarized light component diffracted thereby at the time when the first wavelength range component of said illuminating light is first incident thereon, whereby not less than 70% of the first-stated polarization component is transmitted through the optical device;
• said polarization selective holographic optical device transmitting not less than 70% of the second wavelength range component to radiate the second wavelength range component towards said second reflection type spatial optical modulator;
• said polarization selective holographic optical device diffracting the polarized light component having the direction of polarization perpendicular to the direction of polarization of the polarized light component of the second wavelength range component of the illuminating light re-incident thereon after phase modulation by said second reflection type spatial optical modulator, transmitted therethrough at the time when the second wavelength range component of said illuminating light is first incident thereon;
• said projection optical system projecting the illuminating light of the first wavelength range component through said first reflection type spatial optical modulator and the polarization selective holographic optical device and the illuminating light of the second wavelength range component through said second reflection type spatial optical modulator and the polarization selective holographic optical device on said screen.

(Amended) An image display apparatus comprising:

• a light source for radiating illuminating light;
• a polarization selective holographic optical device for diffracting the incident light, said device including a plurality of each of two areas having refractive index values exhibiting respectively different incidence polarization orientation dependencies, said areas being layered sequentially alternately;
• an illuminating optical system for causing said illuminating light to be incident on said polarization selective holographic optical device;
• a reflection type spatial optical modulator for modulating the state of polarization of the illuminating light diffracted by said polarization selective holographic optical device;
• and
• a optical system for observing a virtual image, for guiding the illuminating light through said reflection type spatial optical modulator to the eye of a viewer;
• said polarization selective holographic optical device, one of two areas of which exhibits refractive index anisotropy, with the other exhibiting refractive index isotropy, being irradiated by said illuminating optical system with the illuminating light at an angle of incidence not less than 30° and less than 90° with respect to a normal line to a light receiving surface thereof for said illuminating light, said polarization selective holographic optical device diffracting a P-polarized light component or an S-polarized light component of said illuminating light to radiate the diffracted light towards said reflection type spatial optical modulator;
• said polarization selective holographic optical device exhibiting the diffraction efficiency of not higher than 10% for the polarized light component of the illuminating light incident a second time thereon after phase modulation by said reflection type spatial optical modulator, which polarized light component has a direction of polarization perpendicular to a direction of polarization of the polarized light component diffracted thereby at the time when the illuminating light is first incident thereon, whereby not less than 70% of the first-stated polarization component is transmitted through the optical device.
• said optical system for observing a virtual image guiding the light transmitted through said polarization selective holographic optical device towards the eye of a viewer.