Abstract: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: The invention relates to a viewing and an image pickup optical system for display devices, which can be used with high efficiency at a plurality of wavelengths and enables bright images to be viewed with satisfactory color reproducibility. The optical system comprises a first prism 3, a second prism 4 and a volume hologram element 6 disposed between them and cemented to them. The hologram element 6 comprises a first grating vector corresponding to at least a first wavelength and a second grating vector corresponding to a second wavelength shorter than the first wavelength.

Abstract: The invention relates to a viewing and an image pickup optical system for display devices, which can be used with high efficiency at a plurality of wavelengths and enables bright images to be viewed with satisfactory color reproducibility and well-corrected aberrations. The optical system comprises a first prism 3, a second prism 4 and a volume hologram element 6 disposed between them and cemented to them. The hologram element 6 comprises a first volume hologram optimized in such a way as to effect diffraction at least at a first wavelength and a second hologram optimized in such a way as to effect diffraction at a second wavelength different from the first wavelength. The first and second holograms forming the hologram element 6 are identical with each other in terms of the shape and spacing of interference fringes on their surfaces but different from each other in terms of the spacing and tilt of interference fringes in their hologram media.

Abstract: An observation optical system includes an image display element b 5, a relay optical system 6 having a plurality of lenses 4 and a first reflection-type volume hologram element (HOE) 8, and an eyepiece optical system having a second reflection-type HOE 9. The observation optical system is arranged along the face to the side head of the observer. The first reflection-type HOE 8 has a power and is configured to compensate for chromatic aberrations. The plurality of lenses is configured to compensate for decentered aberrations and chromatic aberrations. The second reflection-type HOE 9 is configured to exert power on bundles of rays and to compensate for chromatic aberrations. A light-transmitting plate 3 is sandwiched between the first reflection-type HOE 8 and the second reflection-type HOE 9. The light-transmitting plate 3 is configured so that light from the first reflection-type HOE 8 causes total reflection inside the light-transmitting plate 3 odd-numbered times equal to or greater than three times.

Abstract: The present invention is a translucent screen comprising a plurality of spherical lenses arranged in an orthohexagonal lattice structure or a tetragonal lattice structure on a two-dimensional plane, a supporting member disposed at the incident side of the spherical lenses, a diffusion plate which is disposed at the emission side of the spherical lenses where the surface at the side facing the spherical lenses is the diffusion surface, and a shield which connects the spherical lenses, defines the entrance aperture at the incident side and functions as a black matrix at the emission side, wherein the luminous flux entering diagonally is converted to the luminous flux which center is a direction approximately vertical to the main surface of the translucent screen, and are emitted.

Abstract: A viewing optical system for display apparatus allows observation of a bright displayed image favorably corrected for aberrations and is easy to assemble, resistant to impact such as vibration, lightweight and compact. An ocular optical member for leading an observation image formed by an observation image forming member to an exit pupil has a first prism member and a second prism member. The first prism member has a first entrance surface, a reflecting surface and a first exit surface disposed to face each other across a first prism medium. The second prism member has a second entrance surface and a second exit surface disposed to face each other across a second prism medium. The first and second prism members are cemented together with a holographic element interposed between the first exit surface and the second entrance surface. The reflecting surface has a positive power. The first exit surface and the second entrance surface are each formed from a plane or cylindrical surface.

Abstract: An optical system invention is interposed between a pupil plane and an image plane, and includes a first prism, a second prism, and a holographic element which is sandwiched between the first prism and the second prism and is cemented to these prisms. When a light beam traveling along the optical path connecting the pupil plane and the image plane through the optical system is called a first beam, the first prism has a 1-1 surface placed on the pupil side, combining the function of transmission with the function of reflection of the first beam; a 1-2 surface placed on the opposite side of the pupil with respect to the 1-1 surface; and a 1-3 surface placed on the image side, transmitting the first beam. The second prism includes a 2-1 surface having the same shape as the 1-2 surface and placed opposite thereto, transmitting the first beam at least twice, and a 2-2 surface placed on the opposite side of the pupil with respect to the 2-1 surface of the second prism, reflecting the first beam.

Abstract: An observation optical system or a photographing optical system comprises, between a pupil surface and an image surface, a first prism 3 and a second prism. The first prism 3 includes a 1st-1st surface 31 which has both of actions of transmitting and reflecting light in the path, a 1st-2nd surface 32 which has both of actions of reflecting and transmitting the light in the path, and a 1st-3rd surface 33 which transmits the light in the path. The second prism 4 includes a 2nd-1st surface 41 which is disposed adjacent to the 1st-2nd surface 32 at an air space away and which transmits the light in the path at least twice and a 2nd-2nd surface 42 which reflects the light in the path. The 1st-1st surface 31 is constructed of a prism face to which a volume hologram 6 is applied.

Abstract: A zoom lens includes, in order from the object side, a first lens unit with positive refracting power, a second lens unit with negative refracting power, a third lens unit with positive refracting power, and a fourth lens unit with positive refracting power. At least, the second lens unit and the fourth lens unit are moved along the optical axis to change spaces between individual lens units, and thereby the magnification of the zoom lens is changed in the range of the wide-angle position to the telephoto position. In this case, the third lens unit has three positive lens elements and one negative lens element located at the most image-side position.

Abstract: In a viewing optical system using a reflection type image display device and a decentered prism, occurrence of ghost light is prevented which would otherwise be caused by illuminating light reflected from a half-mirror and further reflected from the inner wall of a housing or the like. Illuminating light from a light source (5) passes through a polarizing plate (32) and enters a prism (10) through a polarization beam splitter surface (31) on a surface (13). After being reflected from a surface (12), the light exits from a surface (11) to illuminate a reflective LCD (3). Reflected light from the reflective LCD (3) enters the prism 10 through the surface (11) and exits the prism (10) via the surfaces (12, 13 and 14). The light enters a decentered prism (20) through a surface (21) and is reflected successively by surfaces (23 and 22). The reflected light exits the prism (20) through the surface (23) and displays an enlarged display image in an eye E.

Abstract: A compact, bright and high-performance viewing optical system capable of color display has a reflection type image display device, an ocular optical system and an illuminating device formed from a plurality of juxtaposed illuminating light sources of different colors. An illuminating light guide optical device is placed between the entrance pupil and the reflection type image display device. The ocular optical system includes a decentered prism formed from a medium surrounded by three optical surfaces and having a refractive index larger than 1. A chromatic aberration producing device is placed between the entrance pupil and the illuminating light guide optical device. The chromatic aberration producing device is arranged to superimpose the images of the plurality of illuminating light sources on one another in the exit pupil.

Abstract: An observation optical system comprises an image display element 5 and an eyepiece optical system which introduces an image formed by the image display element 5 to a center of an eye of an observer without forming an intermediate image, so as to allow the observer to observe the image as a virtual image. The eyepiece optical system is constructed and arranged to bend the optical axis using reflecting surfaces so as to be compact. The optical axis lies in a plane, with respect to which the optical system is formed symmetric. The optical system includes a prism 3 having an entrance surface 33, a plurality of curved reflecting surfaces 31, 32 and an exit surface 31. The reflecting surface 32 is provided with a volume hologram (HOE) 4.

Abstract: A compact, bright and high-performance viewing optical system and an image display apparatus using the same. The viewing optical system uses an ocular optical system, which is formed from a decentered prism, and a reflection type image display device. The image display device has a light source and an illuminating light guide prism for guiding a light beam from the light source so that the light beam is applied to the display surface from the front side thereof. The ocular optical system includes a prism having an entrance surface through which a light beam reflected from the display surface enters the prism after passing through the illuminating light guide prism. The prism further has a reflecting surface and an exit surface through which the light beam exits from the prism.

Abstract: An optical system invention is interposed between a pupil plane and an image plane, and includes a first prism, a second prism, and a holographic element which is sandwiched between the first prism and the second prism and is cemented to these prisms. When a light beam traveling along the optical path connecting the pupil plane and the image plane through the optical system is called a first beam, the first prism has a 1-1 surface placed on the pupil side, combining the function of transmission with the function of reflection of the first beam; a 1-2 surface placed on the opposite side of the pupil with respect to the 1-1 surface; and a 1-3 surface placed on the image side, transmitting the first beam. The second prism includes a 2-1 surface having the same shape as the 1-2 surface and placed opposite thereto, transmitting the first beam at least twice, and a 2-2 surface placed on the opposite side of the pupil with respect to the 2-1 surface of the second prism, reflecting the first beam.

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 observation system having a positive refracting power as a whole comprises a first unit G1 with a positive refracting power and a second unit G2 and forms an exit pupil for observation of an electronic image displayed on an image display element 5. The first unit G1 comprises a prism 4 with a positive refracting power and a transmission-type volume hologram 6 and has an action of imaging an observation image for obtaining a relay image. The second unit G2 is composed of a reflection-type volume hologram 3 and has an action of forming the exit pupil 1 so as to introduce the relay image to an observer. At least one of reflecting surfaces and an exit surface of the prism 4 is shaped as a rotationally asymmetric surface which exerts a power on bundles of rays, to compensate aberrations generated by decentering.

Abstract: An image display apparatus having a compact optical system, in which the intermediate image magnifying power of a relay optical system is increased to realize a wide field angle while keeping the power of the concave mirror part of an ocular optical system at a small value. A viewing optical system has an image source-side reflecting surface having a decentered curved surface configuration that gives a power to a light beam emitted from an image display device when the light beam is reflected by the decentered curved surface. The image source-side reflecting surface also has a rotationally asymmetric surface configuration that corrects decentration aberrations produced by reflection at the decentered curved surface.

Abstract: The present invention is a translucent screen comprising a plurality of spherical lenses arranged in an orthohexagonal lattice structure or a tetragonal lattice structure on a two-dimensional plane, a supporting member disposed at the incident side of the spherical lenses, a diffusion plate which is disposed at the emission side of the spherical lenses where the surface at the side facing the spherical lenses is the diffusion surface, and a shield which connects the spherical lenses, defines the entrance aperture at the incident side and functions as a black matrix at the emission side, wherein the luminous flux entering diagonally is converted to the luminous flux which center is a direction approximately vertical to the main surface of the translucent screen, and are emitted.

Abstract: In a viewing optical system using a reflection type image display device and a decentered prism, occurrence of ghost light is prevented which would otherwise be caused by illuminating light reflected from a half-mirror and further reflected from the inner wall of a housing or the like. Illuminating light from a light source (5) passes through a polarizing plate (32) and enters a prism (10) through a polarization beam splitter surface (31) on a surface (13). After being reflected from a surface (12), the light exits from a surface (11) to illuminate a reflective LCD (3). Reflected light from the reflective LCD (3) enters the prism 10 through the surface (11) and exits the prism (10) via the surfaces (12, 13 and 14). The light enters a decentered prism (20) through a surface (21) and is reflected successively by surfaces (23 and 22). The reflected light exits the prism (20) through the surface (23) and displays an enlarged display image in an eye E.

Abstract: A compact, bright and high-performance viewing optical system capable of color display has a reflection type image display device, an ocular optical system and an illuminating device formed from a plurality of juxtaposed illuminating light sources of different colors. An illuminating light guide optical device is placed between the entrance pupil and the reflection type image display device. The ocular optical system includes a decentered prism formed from a medium surrounded by three optical surfaces and having a refractive index larger than 1. A chromatic aberration producing device is placed between the entrance pupil and the illuminating light guide optical device. The chromatic aberration producing device is arranged to superimpose the images of the plurality of illuminating light sources on one another in the exit pupil.