Abstract: An optical element assembly includes a first optical element, a second optical element, and a positioning holder member. The first optical element has engageably shaped portions in a peripheral portion of an effective area on a first injection surface through which the effective luminous flux passes. These engageably shaped portions respectively correspond to one engageably shaped portions formed on one opponent surface of the positioning holder member that opposes the first injection surface. The second optical element has engageably shaped portions in a peripheral portion of an effective area on a second incident surface through which the effective luminous flux passes. These engageably shaped portions respectively correspond to the other engageably shaped portions formed on the other opponent surface of the positioning holder member that opposes the second incident surface.

Abstract: The invention relates to an optical system or apparatus such as a lens system capable of focus control and a variable-focus lens, which has reduced power consumptions, ensures noiseless operation and fast response and contributes to cost reductions for the reason of simplified structure. Specifically, the invention provides an optical apparatus comprising an element 409 having variable optical properties and an image plane 612. To correct the optical apparatus for movement of the image-formation surface of an optical system 614 in association with a change in the element 409 having variable optical properties, the image plane 612 is placed in the range of movement of the image-formation surface in association with the change in the element having variable optical properties.

Abstract: A high-performance and low-cost image-forming optical system with a reduced number of constituent optical elements that is made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. The image-forming optical system has a first prism and a second prism between a stop and an image plane. The first prism includes an entrance surface, a first reflecting surface, a second reflecting surface, and an exit surface. The first reflecting surface and the exit surface are the identical surface. The second prism includes an entrance surface, a first reflecting surface, a second reflecting surface, and an exit surface. In the second prism, the second reflecting surface and the entrance surface are the identical surface.

Abstract: The decentering optical system comprises a decentering prism and a holding component. The decentering prism has two or more positioning portions at positions which sandwich an effective diameter of an optically functional surface held by the holding component. The holding component has a holding portion of positioning portions corresponding to the positioning portions of the decentering prism. Furthermore, on the optically functional surface of the decentering prism, two and more projected portions are arranged at a position which sandwich the effective diameter of the optically functional surface and is located at the outside of the positioning portion, and a projected portion is located inside of the positioning portion. The decentering prism is fixed for positioning at the holding component through the positioning portion, the holding portion of the positioning portion and the projected portions.

Abstract: The invention relates to an optical system that has reduced power consumptions, ensures noiseless operations and fast responses, contributes to cost reductions due to simplified mechanical structure, and, albeit having a small outside diameter and small size, is capable of focusing and zooming. The optical system of the invention comprises a variable mirror and a moving optical element group. The optical element group has a zooming function, and the variable mirror has a focusing function. An optical apparatus of the invention comprises such an optical system as mentioned above.

Abstract: An image pickup optical system includes, in order from the object side, a front unit having at least one reflecting surface with power that is rotationally asymmetrical, an aperture stop, and a rear unit having at least one reflecting surface with power that is rotationally asymmetrical. In this case, F-numbers in two directions perpendicular to each other on a plane perpendicular to the optical axis are different. Decentration takes place in one of the two directions and the F-number in a direction perpendicular to a decentering direction is smaller than that in the decentering direction. When the F-number in the decentering direction is represented by FNY and the F-number in the direction perpendicular to the decentering direction is represented by FNX, the optical system satisfies the following condition: 1.1<FNY/FNX<2.

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: The invention relates to an optical system or apparatus such as a lens system capable of focus control and a variable-focus lens, which has reduced power consumptions, ensures noiseless operation and fast response and contributes to cost reductions for the reason of simplified structure. Specifically, the invention provides an optical apparatus comprising an element 409 having variable optical properties and an image plane 612. To correct the optical apparatus for movement of the image-formation surface of an optical system 614 in association with a change in the element 409 having variable optical properties, the image plane 612 is placed in the range of movement of the image-formation surface in association with the change in the element having variable optical properties.

Abstract: A zoom optical system includes at least two optical-element groups and a variable optical-property optical element. The two optical-element groups are movable in a magnification change and have a magnification varying function or a compensating function for compensating for a shift of an image surface caused by the magnification change. The optical element has a focusing function and is disposed on the image side of the optical-element groups. According to this configuration of the zoom optical system, it is possible to attain a zoom optical system and an imaging apparatus using the zoom optical system that have as small a number of movable lenses as possible, are very small in size, and work with an extremely low power consumption and low operation noise.

Abstract: A zoom optical system includes only one optical-element group moved in a magnification change and at least one deformable mirror having a compensating function for compensating for a shift of an image surface caused by the magnification change and a focusing function. According to this configuration of the zoom optical system, it is possible to attain a zoom optical system and an imaging apparatus using the zoom optical system that have as small a number of movable lenses as possible, are very small in size, and work with an extremely low power consumption and low operation noise.

Abstract: The present invention relates to an image display apparatus, e.g. a head-mounted 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. The image display apparatus has an optical path distributing mirror 1 for distributing the image of a single display device 10 to an optical path for a right eye and an optical path for a left eye, and an ocular prism 2R for the right eye and an ocular prism 2L for the left eye, which are placed on the right- and left-hand sides, respectively, of the optical path distributing mirror 1.

Abstract: A high-performance and low-cost image-forming optical system has a reduced number of constituent optical elements and is made extremely thin, particularly in a direction perpendicular to an image pickup device, by folding an optical path using only three reflecting surfaces. The image-forming optical system has a front unit including a first prism 10, an aperture stop 2, and a rear unit including a second prism 20. The first prism 10 has a first transmitting surface 11, a first reflecting surface 12, and a second transmitting surface 13. The second prism 20 has a first transmitting surface 21, a first reflecting surface 22, a second reflecting surface 23, and a second transmitting surface 24. An optical path incident on the first reflecting surface 22 and an optical path exiting from the second reflecting surface 23 intersect each other.

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: The invention relates to an optical system that has reduced power consumptions, ensures noiseless operations and fast responses, contributes to cost reductions due to simplified mechanical structure, and, albeit having a small outside diameter and small size, is capable of focusing and zooming. The optical system of the invention comprises a variable mirror and a moving optical element group. The optical element group has a zooming function, and the variable mirror has a focusing function. An optical apparatus of the invention comprises such an optical system as mentioned above.

Abstract: A high-performance and low-cost image-forming optical system has a reduced number of constituent optical elements and is made extremely thin, particularly in a direction perpendicular to an image pickup device, by folding an optical path using only three reflecting surfaces. The image-forming optical system has a front unit including a first prism 10, an aperture stop 2, and a rear unit including a second prism 20. The first prism 10 has a first transmitting surface 11, a first reflecting surface 12, and a second transmitting surface 13. The second prism 20 has a first transmitting surface 21, a first reflecting surface 22, a second reflecting surface 23, and a second transmitting surface 24. An optical path incident on the first reflecting surface 22 and an optical path exiting from the second reflecting surface 23 intersect each other.

Abstract: The invention relates to an optical system or apparatus such as a lens system capable of focus control and a variable-focus lens, which has reduced power consumptions, ensures noiseless operation and fast response and contributes to cost reductions for the reason of simplified structure. Specifically, the invention provides an optical apparatus comprising an element 409 having variable optical properties and an image plane 612. To correct the optical apparatus for movement of the image-formation surface of an optical system 614 in association with a change in the element 409 having variable optical properties, the image plane 612 is placed in the range of movement of the image-formation surface in association with the change in the element having variable optical properties.

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 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: A high-performance and low-cost image-forming optical system has a reduced number of constituent optical elements and is made extremely thin, particularly in a direction perpendicular to an image pickup device, by folding an optical path using only three reflecting surfaces. The image-forming optical system has a front unit including a first prism 10, an aperture stop 2, and a rear unit including a second prism 20. The first prism 10 has a first transmitting surface 11, a first reflecting surface 12, and a second transmitting surface 13. The second prism 20 has a first transmitting surface 21, a first reflecting surface 22, a second reflecting surface 23, and a second transmitting surface 24. An optical path incident on the first reflecting surface 22 and an optical path exiting from the second reflecting surface 23 intersect each other.