Abstract: An imaging optical system has a variable magnification optical system. The variable magnification optical system includes, in order from the object side, a first lens unit with positive refractive power, a second lens unit with positive refractive power, a third lens unit with negative refractive power, a fourth lens unit with positive refractive power, and an aperture stop interposed between the third lens unit and the fourth lens unit. The variable magnification optical system changes an imaging magnification while keeping an object-to-image distance constant. The imaging magnification is changed by varying spacing between the first lens unit and the second lens unit, spacing between the second lens unit and the third lens unit, and spacing between the third lens unit and the fourth lens unit. When the imaging magnification is changed, the imaging optical system satisfies the following conditions in at least one variable magnification state: |En|/L>0.

Abstract: An image capturing unit comprises a variable optical element, an optical unit, and a light-flux limiting section. The variable optical element includes a first liquid member, a second liquid member, and a container which contains the first liquid member and the second liquid member. An interfacial shape between the first liquid member and the second liquid member varies according to a voltage which is applied to the liquid members.

Abstract: A variable optical element is formed by a first liquid member, a second liquid member which is unsoluble in the first liquid member, a container which contains the first liquid member and the second liquid member, an index for positioning the variable optical element according to a predetermined reference. In the variable optical element, an interfacial shape between the first liquid and the second liquid surface varies according to a voltage which is applied to the liquid members, and the index is disposed such that a wave front aberration in the variable optical element should be minimum or fewer than a predetermined value under condition that the variable optical element is positioned according to the predetermined reference. By doing this, it is possible to restrict the wave front aberration which is caused by a gravity in the variable optical element, the optical unit, and the image capturing device.

Abstract: An observation optical system comprises an image display element and an eyepiece optical system which introduces an image formed by the image display element 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 image observation optical system can be made compact enough to be usable as an image display unit for a cellular phone or a portable intelligent terminal, and can achieve high image definition and wide field angle while controlling chromatic aberration of magnification to be small.

Abstract: An imaging optical system has a variable magnification optical system. The variable magnification optical system includes, in order from the object side, a first lens unit with positive refractive power, a second lens unit with positive refractive power, a third lens unit with negative refractive power, a fourth lens unit with positive refractive power, and an aperture stop interposed between the third lens unit and the fourth lens unit. The variable magnification optical system changes an imaging magnification while keeping an object-to-image distance constant. The imaging magnification is changed by varying spacing between the first lens unit and the second lens unit, spacing between the second lens unit and the third lens unit, and spacing between the third lens unit and the fourth lens unit.

Abstract: An image forming optical system includes, comprises, in order from the object side toward the image side, a first lens unit with positive refracting power, a second lens unit with positive refracting power, a third lens unit with negative refracting power, a fourth lens unit with positive refracting power, and an aperture stop interposed between the third lens unit and the fourth lens unit. The image forming optical system has a variable magnification optical system in which spacings between these lens units are changed to vary the imaging magnification, changes the imaging magnification while constantly keeping the object-to-image distance of the image forming optical system, and in at least one variable magnification state where the imaging magnification is changed, satisfies the following conditions: |En|/L>0.4 |Ex|/|L/&bgr;|>0.

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: 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: A zoom optical system includes a deformable element having a focusing function and two lens groups movable in a magnification change and having a magnification varying function or a compensating function for compensating for a shift of an image surface. Alternatively, a zoom optical system includes, in order from the object side, a first group having a negative power and being fixed in a magnification change, a second group having a positive power and being movable in a magnification change, and a third group movable in a magnification change. The first group has a deformable element having a focusing function. An imaging apparatus is provided with either zoom optical system. Whereby, a high-performance zoom optical system with small fluctuation of aberrations in spite of use of a deformable element and a photographing apparatus using the same zoom optical system are provided.

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: An observation optical system includes an image display element, a relay optical system having a plurality of lenses 4 and a first reflection-type volume hologram element (HOE), and an eyepiece optical system having a second reflection-type HOE. The observation optical system is arranged along the face to the side head of the observer. The first reflection-type HOE 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 is a configured to exert power on bundles of rays and to compensate for chromatic aberrations. A light-transmitting plate is sandwiched between the first reflection-type HOE and the second refection-type HOE.

Abstract: A viewing optical system for display devices or an image pickup optical system, 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, a second prism and a volume hologram element disposed between them and cemented to them. The hologram element 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 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: A viewing optical system for display apparatus, includes 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. The holographic element also has a plane of cylindrical surface.

Abstract: The invention relates to an optical connector module that can accommodate well to a wide wavelength-band range and provide a high-precision connection by adjustment of only one lens. Operating to enter optical signals emerging from a plurality of input optical waveguides 10 and having a wavelength in the range of 1.2 &mgr;m to 1.7 &mgr;m in a plurality of output optical waveguides 20, the optical connector module uses one bilateral telecentric optical system 1 to provide optical connections of at least two light beams from the input optical waveguides 10 to the output optical waveguides 20.

Abstract: The invention provides an optical element that has a low refractive-index chromatic dispersion, a high degree of freedom in molding or forming as is the case with synthetic resins, and moldability or formability that lends itself to mass production. The optical element is obtained by molding or otherwise forming a composition containing a first material that is a fine particle having an Abbe number vd of 80 or greater indicative of a chromatic dispersion in a visible range and having a size of less than 400 nm, and a second material that is an organic/inorganic hybrid material comprising an organic polymer material having a carbon-carbon bond in a main chain and an inorganic component.

Abstract: The present invention relates to a compact and low-cost image pickup apparatus capable of providing high-quality images comparable to silver halide photographs and also capable of obtaining photographic effects equivalent to those which are available for silver halide photographs, e.g. utilization of blurring. In the image pickup apparatus, an image of an object produced by an optical system is formed on an electronic image pickup device, thereby obtaining image information concerning the object. The image pickup device 20 is a device having a matrix or mosaic color filter array provided over a photoelectric conversion surface, and the electronic image pickup device 20 and the optical system 10 satisfy the conditions: (1) 6.2/{square root over ( )}N<P<21/{square root over ( )}N; (2) 3.8<N<20; (3) 3.4×P−25<N<20; and (4) 0<&thgr;<1.

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: 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: 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 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.