Abstract: An optical device having a dioptric correction device comprises a reference image display unit which is placed in the optical path extending from an object image to the optical system. The reference image is used for dioptric correction. The left and right reference images are different and are displayed on the left and right reference image display units when dioptric correction is performed. The reference image display unit is placed at a predetermined position between the optical system and an image display unit. Since the reference image is positioned at the predetermined position, both of the image of the image display unit and the reference image may be seen clearly.

Abstract: A driving device (actuator) 10 includes a driving shaft 16 which is Linearly driven in the axial direction by a piezoelectric element 15 and two disks 18a and 18b which are made of an elastic material and fixed to a rotary shaft 17. Peripheral portions of the two disks 18a and 18b vertically hold the driving shaft 16 between them so as to be frictionally coupled with the driving shaft 16 by their elastic forces. When the driving shaft 16 is linearly driven in the axial direction by the piezoelectric element 15, the peripheral portions of the two disks 18a and 18b receive a force in the tangential direction and rotate around the rotary shaft 17.

Abstract: A resonant optical device has a rod-like resonator made of a fiber-reinforced resin for resonant vibration. A reflecting mirror is supported on the leading edge of the resonator. A drive unit oscillates the resonator in a circumferential direction. The base edge of the resonator is anchored to a stationary platform. The reflecting mirror is oscillated by a torsional oscillation produced by oscillation from the drive unit so as to scan light incident on the reflecting mirror. The resonator satisfies the expression G/.rho..gtoreq.12.times.10.sup.6 Pa.multidot.kg.sup.-1 .multidot.m.sup.3, where the horizontal elastic modulus of the resonator is designated G, and the density is designated .rho.. The resonator also satisfies the expression .tau./G.gtoreq.0.01, where the torsional stress tolerance is designated .tau.. In one embodiment, the fiber-reinforced resin is a carbon fiber-reinforced resin.

Abstract: In a stereoscopic system including a three-dimensional camera and an HMD, by setting the convergences of the three-dimensional camera and the HMD in accordance with the distance to the object to be shot, a stereoscopically viewable object distance range is increased and a natural stereoscopic image is provided. The three-dimensional camera is provided with a convergence setter which varies the directions of left and right cameras, and the HMD is provided with a convergence setter which varies the directions of left and right virtual image projectors. The distance to the object is detected based on the distance between the left and right images taken by the three-dimensional camera, and the convergence setters of the three-dimensional camera and the HMD are controlled in accordance with the detected distance. The convergence setter of the three-dimensional camera performs focusing, interlocking with the convergence setting.

Abstract: An image taken by a mobile camera is displayed on a head-mounted display provided with an acceleration sensor to detect movement of the observer's head, and the size of the image viewed by the observer wearing the display is varied according to the movement of the observer's head. For varying the image size, the camera is equipped with a zoom lens to change the size of shooting area, or alternatively, the display is equipped with a zoom lens as the eyepiece to enlarge or reduce the size of the displayed image. An image showing the appearance of the camera is displayed being superimposed on the image taken by the camera in order to facilitate the control of the camera by the observer.

Abstract: An HMD is provided with two piezoelectric vibrating gyros which detect vertical and horizontal angular velocities, and a horizontal sensor which detects a vertical angle. While the user's head rotates, shooting direction of a three-dimensional camera is varied in accordance with the angles obtained by integration of the detected angular velocities. While the head is stationary, the obtained vertical angle and the output of the gyro is corrected based on the angle detected by the horizontal sensor. The shooting direction of the camera can be manually set irrespective of the direction of the head, and information on the viewing direction is displayed together with a taken image.

Abstract: A movable stage utilizing an electromechanical transducer. An actuator as a drive source thereof is composed of piezoelectric elements, drive member fixed thereto and a movable member friction-coupled with the drive member. When a drive pulse is applied to the piezoelectric element to cause it to show reciprocal displacements at different rates in the thickness direction, the movable member frictionally coupled with the drive member moves in the predetermined direction to move the movable table coupled with the movable member in the predetermined direction. The movable stage comprising the movable table moving in the two axes or three axes can be constituted by providing the actuator in the two axes or three axes crossing with each other.