Abstract: To provide an optical apparatus which controls an interface state to change a focal length by using an optical element having a container sealing first liquid that is conductive or polarized and second liquid that does not mutually mix with the first liquid with their interface in a predetermined form and electrodes provided in the container and of which optical characteristics change according to change of interface form due to application of voltage to the electrodes, and in particular an optical apparatus that controls a duty ratio of alternating current voltage applied to said electrodes for changing said interface form.

Abstract: To provide an optical apparatus which controls an interface state to change a focal length by using an optical element having a container sealing first liquid that is conductive or polarized and second liquid that does not mutually mix with the first liquid with their interface in a predetermined form and electrodes provided in the container and of which optical characteristics change according to change of interface form due to application of voltage to the electrodes, and in particular an optical apparatus that controls a duty ratio of alternating current voltage applied to said electrodes for changing said interface form.

Abstract: An optical device capable of controlling its optical transmittance. The optical device has a first liquid conductive or having a polarity and a second liquid. The first and second liquids are substantially equal in refractive index but differ in transmittance. The first and second liquids do not mix with each other. The first and second liquids are sealingly contained in a container in such state that the boundary therebetween has a predetermined shape. When a voltage is applied between these liquids through electrodes formed in such a place or condition as to avoid interference with passage of a bundle of rays incident upon the optical element, the output of the applied voltage is selected under control to change the shape of the boundary, thereby changing the quantity of transmitted light in the bundle of rays traveling through the optical device.

Abstract: To provide an optical apparatus which controls an interface state to change a focal length by using an optical element having a container sealing first liquid that is conductive or polarized and second liquid that does not mutually mix with the first liquid with their interface in a predetermined form and electrodes provided in the container and of which optical characteristics change according to change of interface form due to application of voltage to the electrodes, and in particular an optical apparatus that controls a duty ratio of alternating current voltage applied to said electrodes for changing said interface form.

Abstract: An optical device capable of controlling its optical transmittance. The optical device has a first liquid conductive or having a polarity and a second liquid. The first and second liquids are substantially equal in refractive index but differ in transmittance. The first and second liquids do not mix with each other. The first and second liquids are sealingly contained in a container in such state that the boundary therebetween has a predetermined shape. When a voltage is applied between these liquids through electrodes formed in such a place or condition as to avoid interference with passage of a bundle of rays incident upon the optical element, the output of the applied voltage is selected under control to change the shape of the boundary, thereby changing the quantity of transmitted light in the bundle of rays traveling through the optical device.

Abstract: An image display apparatus includes a storage display element having a screen portion which receives image light from its back side and stores and displays an image, and a light blocking mechanism. The light blocking mechanism is capable of being switched over between a light-blocked state in which the light blocking mechanism blocks light incident on the front side of the screen portion of the storage display element to shut off incidence of external light on the screen portion, and an observation-possible state in which the light blocking mechanism unblocks light incident on the front side of the screen portion of the storage display element.

Abstract: An apparatus, such as a camera, including a first drive power transmission system for transmitting drive power to a finder in order to correct parallax, a second drive transmission system for transmitting drive power to an operating device for operating the device, and a drive power supplying device for selectively supplying drive power to the first drive power transmission system and the second drive power transmission system.