Image display apparatus

An image display apparatus comprising:

• reflective display means;
• an illumination optical system for guiding light from light source means to the display means;
• and
• a display optical system for guiding the light reflected by the display means to the eye of an observer to allow the observer to observe an image without forming an intermediate image of an image information displayed on the display means,
• wherein at least one surface of the display optical system is a rotationally asymmetric surface which is decentered with respect to the light guided to the observer from said display means and which reflects the light guided to the observer from said display means, a principal ray of display light at a center of a field of view from the display means is emergent at a predetermined angle relative to a normal to a display surface of the display means, the illumination optical system and the display optical system share at least one optical element which does not include said rotationally asymmetric surface which is decentered with respect to the light guided to the observer from said display means and which reflects the light guided to the observer from said display means, and at least one surface of the optical element(s) is a curved surface.

An image display apparatus comprising:

• reflective display means;
• an illumination optical system for making light from light source means incident to a display surface of the display means;
• and
• a display optical system for guiding light from the display means to the pupil of an observer to allow the observer to observe image information displayed on the display means,
• wherein the illumination optical system guides the light from the light source means via a prism of a triangular prism shape making use of a totally reflecting surface to the display means, the display optical system guides the light from the display means through the totally reflecting surface of the prism to the observer, and an angle θ between the totally reflecting surface and the display surface of the display means is set so as to satisfy the following condition:
• (Dy/Ly)·Wy°<θ<40°
• where Dy represents a diameter of the exit pupil formed by the display optical system in the y-direction,
• Ly represents an effective image display size of the display means in the y-direction, and
• Wy represents a field of view in the y-direction.

An image display apparatus comprising:

• light source means;
• reflective display means;
• an illumination optical system for guiding light from the light source means to the display means;
• a display optical system for guiding the light reflected by the display means to the pupil of an observer and making the observer recognize a virtual image formed thereby as an enlarged image of an image displayed on the display means;
• and
• an optical member comprising surface acting to totally reflect light when guiding the light from the light source means to the display means and acting to transmit light when guiding the light reflected by the display means to the pupil,
• wherein an angle θ between the surface and an image display surface of the display means is set to satisfy θ<45°.

An image display apparatus comprising:

• reflective display means;
• an illumination optical system for making light from light source means incident to a display surface of the display means;
• and
• a display optical system for guiding light from the display means to the pupil of an observer to allow the observer to observe image information displayed on the display means,
• wherein the illumination optical system guides the light from the light source means via an optical member making use of a totally reflecting surface to the display means and the display optical system guides the light from the display means through the totally reflecting surface of the optical member to the observer.

An image display apparatus comprising:

• reflective display means;
• an illumination optical system for making light from light source means incident to a display surface of the display means;
• and
• a display optical system for guiding light from the display means to the pupil of an observer to allow the observer to observe image information displayed on the display means, wherein said illumination optical system includes an optical member having a positive power independent of said display optical system, and a divergent light beam from the light source means is converged by said optical member of said illumination optical system and guided to said display means, and
• wherein the display optical system is arranged so as not to interfere with an illumination optical path running from the light source means to the display means and the illumination optical system is arranged so as not to interfere with a display optical path running from the display means to the display optical system.

An image display apparatus comprising:

• reflective display means;
• an illumination optical system for making light from light source means incident to the display means;
• and
• a display optical system for guiding light from the display means to an observation position of an observer, the display optical system comprising a plurality of decentered reflecting surfaces each having an optical power, said reflecting surfaces being decentered with respect to a principal ray at a center of a field of view,
• wherein the principal ray at the center of a field of view passes a center of an exit pupil of the display optical system and is emergent at a predetermined angle relative to a normal to an image display surface of the display means, and
• wherein the illumination optical system and the display optical system have a common surface which acts as a reflecting surface when the light from the light source means is guided to the display means and which acts as a transparent surface when the light from the display means is guided to the observer.

An image display apparatus comprising:

• reflective display means;
• an illumination optical system for making light from light source means obliquely incident to a display surface of the display means;
• and
• a display optical system for guiding light from the display means to an observer to permit the observer to observe image information displayed on the display means,
• wherein a principal ray emerging from a central part of the display means is emergent obliquely with respect to the display surface from the display means, the display optical system comprises a decentered, rotationally asymmetric, reflecting surface, the illumination optical system and the display optical system share at least one optical element, and at least one surface of the optical element(s) shared is a curved surface, and
• wherein said optical element comprises a surface acting as a transmitting surface in an optical path of said display optical system and acting as a reflecting surface in an optical path of said illumination optical system.

An image display apparatus comprising:

• reflective display means;
• an illumination optical system for guiding light from light source means to the display means;
• and
• a display optical system for guiding the light reflected by the display means to the eye of an observer to allow the observer to observe an image,
• wherein at least one surface of the display optical system is a decentered, rotationally asymmetric, reflecting surface, a principal ray of display light at a center of a field of view from the display means is emergent at a predetermined angle relative to a normal to a display surface of the display means, the illumination optical system and the display optical system share at least one optical element, and at least one surface of the optical element(s) is a curved surface, and
• wherein said optical element comprises a surface acting as a transmitting surface in an optical path of said display optical system and acting as a reflecting surface in an optical path of said illumination optical system.

An image display apparatus comprising:

• reflective display means;
• an illumination optical system for making light from light source means incident to the display means;
• and
• a display optical system for guiding light from the display means to an observation position of an observer, the display optical system comprising a plurality of decentered reflecting surfaces each having an optical power, said reflecting surfaces being decentered with respect to a principal ray at a center of a field of view,
• wherein the illumination optical system and the display optical system share at least one optical element having a curved surface, and
• wherein the illumination optical system and the display optical system have a common surface which acts as a reflecting surface when the light from the light source means is guided to the display means and which acts as a transparent surface when the light from the display means is guided to the observer.