Abstract: The present invention relates to an image display apparatus in which an image from a single image display device is led to two eyes without using a half-mirror, thereby allowing observation of a bright image and facilitating correction of various aberrations. A viewing optical system includes a left ocular part 10L, a right ocular part 10R, and an optical path distributing part 20 for leading a light beam from a single image display device 3 to the left and right ocular parts 10L and 10R. The left and right ocular parts each have at least two reflecting surfaces 12R(L) and 13R(L). The planes of decentered optical paths of the axial principal rays in the left and right ocular parts are arranged to be approximately parallel to each other.

Abstract: The present invention relates to an image display apparatus in which an image from a single image display device is led to two eyes without using a half-mirror, thereby allowing observation of a bright image and facilitating correction of various aberrations. A viewing optical system includes a left ocular part 10L, a right ocular part 10R, and an optical path distributing part 20 for leading a light beam from a single image display device 3 to the left and right ocular parts 10L and 10R. The left and right ocular parts each have at least two reflecting surfaces 12R(L) and 13R(L). The planes of decentered optical paths of the axial principal rays in the left and right ocular parts are arranged to be approximately parallel to each other.

Abstract: An image display apparatus having a three-dimensionally decentered optical path to attain a reduction in overall size of the apparatus and to place constituent members effectively in a dead space, thereby permitting the apparatus to be designed in a variety of ways. The apparatus includes an image display device and a viewing optical system for leading an image formed by the image display device to a pupil. The viewing optical system has at least a first reflecting surface and a second reflecting surface positioned closer to the pupil than the first reflecting surface along the optical path. A first plane defined by the optical axis incident on the first reflecting surface and the optical axis reflected therefrom and a second plane defined by the optical axis incident on the second reflecting surface and the optical axis reflected therefrom intersect each other at an arbitrary angle, thereby forming a three-dimensionally decentered optical path.

Abstract: An image display apparatus allows an image from a single image display device to be led to two eyes without using a half-mirror, thereby allowing observation of a bright image, and facilitates correction of various aberrations. A viewing optical system includes a left ocular part, a right ocular part, and an optical path distributing part for leading a light beam from a single image display device to the left and right ocular parts. The left and right ocular parts each have at least two reflecting surfaces. The optical path distributing part has at least one pair of reflecting surfaces for left and right optical paths. These reflecting surfaces are formed from rotationally asymmetric curved reflecting surfaces having the function of correcting decentration aberrations.

Abstract: The invention provides an optical apparatus enabling diopter adjustment, etc. to be achieved using, for instance, a reflection type variable-optical property optical element or a variable-optical property mirror but without recourse to any mechanical moving part. The variable-optical property mirror 9 comprises an aluminum-coated thin film 9a and a plurality of electrodes 9b. Via variable resistors 11 and a power source switch 13 a power source 12 is connected between the thin film 9a and the electrodes 9b, so that the resistance values of the variable resistors 11 can be controlled by an operating unit 14. The shape of the thin film 9a as a reflecting surface is controlled by changing the resistance value of each variable resistor 11 in response to a signal from the operating unit 14 in such a manner that the imaging capability of the variable mirror is optimized.

Abstract: An image display apparatus having a three-dimensionally decentered optical path to attain a reduction in overall size of the apparatus and to place constituent members effectively in a dead space, thereby permitting the apparatus to be designed in a variety of ways. The apparatus includes an image display device and a viewing optical system for leading an image formed by the image display device to a pupil. The viewing optical system has at least a first reflecting surface and a second reflecting surface positioned closer to the pupil than the first reflecting surface along the optical path. A first plane defined by the optical axis incident on the first reflecting surface and the optical axis reflected therefrom and a second plane defined by the optical axis incident on the second reflecting surface and the optical axis reflected therefrom intersect each other at an arbitrary angle, thereby forming a three-dimensionally decentered optical path.

Abstract: A fast and compact decentered optical system corrected for aberrations due to three-dimensional decentration by three-dimensionally disposing a rotationally asymmetric surface having no plane of symmetry. The decentered optical system includes at least one optical surface with a rotationally asymmetric surface configuration having no plane of symmetry and having a positive power. The decentered optical system has an entrance surface, at least three reflecting surfaces, and an exit surface. At least one of intersections between an optical axis and the entrance surface, the reflecting surfaces and the exit surface is not in a plane where the other intersections are present.

Abstract: The invention provides a high-performance zoom lens system which is well corrected for chromatic aberrations by use of a DOE, makes the angle of incidence of a ray bundle on a diffractive surface as small as possible from a wide-angle side to a telephoto side thereof, and ensures the sufficient number of DOE gratings with respect to the ray bundle. The zoom lens system comprises a negative lens group G2 taking the largest zooming action and at least one positive lens group G3 on an image side thereof. The positive lens group G3 is constructed of one diffractive optical element having a diffractive surface r.sub.10.

Abstract: The invention relates to a high-performance zoom lens system which can use a diffractive surface therein for use with an image sensor having a number of pixels. The zoom lens system includes at least a first lens group G1 having positive power and a second lens group G2 having negative power between an object side of the system and an aperture stop S. The first lens group G1 includes at least one diffractive surface r.sub.1, and satisfies the following condition:0.001<f.sub.S /f.sub.DOE <0.025 (1)Here f.sub.S =.sqroot.f(f.sub.W .times.f.sub.T) wherein f.sub.W and f.sub.T are focal lengths of the zoom lens system at its wide-angle end and its telephoto end, respectively, and f.sub.DOE is a focal length of the diffractive surface r.sub.1.

Abstract: The invention provides an inexpensive phototaking lens system comprising a reduced number of lenses, which makes use of a diffractive optical element to make correction for first-order longitudinal chromatic aberration and chromatic aberration of magnification, and eliminates higher-order chromatic aberrations of magnification produced in a wide-angle lens system. The phototaking lens system comprises a front group having negative power, an aperture stop and a rear group having positive power, with the rear group comprising at least one positive lens and a diffractive optical element having a diffractive surface D of positive power, and satisfies conditions for making good correction for chromatic aberrations produced at a refractive system with the diffractive optical element and conditions for making well-balanced correction for longitudinal chromatic aberration and chromatic aberration of magnification.

Abstract: The invention provides an inexpensive wide-angle lens system which is well corrected for longitudinal chromatic aberration and chromatic aberration of magnification without recourse to any anomalous dispersion glass while a long enough back focus is fully ensured. The wide-angle lens system comprises a front lens group comprising at least one positive lens and having negative power as a whole, an aperture stop 10, and a rear lens group comprising at least one negative lens and a diffractive optical element 11 having a diffractive surface of positive power, and having positive power as a whole, and satisfies 0.005<f/f.sub.DOE <0.03 where f is a focal length of the wide-angle lens system and f.sub.DOE is a focal length of the diffractive surface provided that f.sub.DOE is free of power of a substrate.

Abstract: A reading lens system composed, in order from the object side, of a first positive biconvex lens component, a second positive meniscus lens component convex toward the image side and an aperture stop disposed on the image side of the second lens component. By setting a distance as measured from a first surface to an aperture stop of the reading lens system adequately, it is configured so as to have a short total length and allow little variation of a size of an image even when the image is defocused due to a variation of an object location.