Abstract: A liquid crystal cell which minimizes disordered orientation occurring with temperature changes even across a wide range, to exhibit good contrast and high reliability, as well as a smectic liquid crystal composition for use the liquid crystal cell are provided. In smectic liquid crystal compositions having a layer construction in the liquid crystal molecular arrangement, it was found that antiferroelectric liquid crystal compositions resistant to variation in the layer spacing of the smectic phase due to temperature changes are resistant to disordered orientation. Specifically, if the antiferroelectric liquid crystal composition contains at lest 45 wt % of an antiferroelectric liquid crystal compound with roughly constant layer spacing in a temperature range from the temperature t.sub.1 which gives the minimum value for the layer spacing of the smectic C.sub.A * phase to -20.degree. C., no disordered liquid crystal orientation results even after cold/hot temperature cycles.

Abstract: The novel liquid crystal compounds of the present invention are represented by the following formulas ?I!-?II! and have tristable molecular orientation states and can be used for display devices and electrooptical devices. ##STR1## wherein R.sub.1 represents an alkyl group of 5-18 carbon atoms; R.sub.2 represents an alkyl group of 6-16 carbon atoms; R.sub.3 represents an alkyl group of 8-18 carbon atoms; R.sub.4 represents an alkyl group of 6-14 carbon atoms; Y represents ##STR2## and * indicates an optically active center.

Abstract: A display device in which an area corresponding to electrodes placed one upon another is arranged to change into a light-transmissive state by applying a potential difference between the electrodes includes a pair of transparent electrodes respectively formed on a pair of transparent substrates, one of the pair of transparent electrodes having at least an electrode area of the same shape as a display pattern, a display substance disposed between the pair of transparent substrates, and a third transparent substrate disposed between the pair of transparent substrates, the third transparent substrate having a transparent electrode formed in an area other than an area corresponding to the display pattern.

Abstract: An optical apparatus includes a projection optical system for projecting an object image; a focal detection system for detecting a defocus state of the object image with respect to a photosensitive plane by a light emitted from the projection optical system; a finder system for observing the object by the light emitted from the projection optical system, the finder system being provided with a light modulation unit for creating a light transmission state when electric energy is input and a cutoff state when electric energy is not input, and the light modulation unit being disposed so as to cover the view field of the finder system; and a control unit for controlling input of the electric energy to a light modulation unit, the control unit controlling so as not to input electric energy when the user does not look through the finder system.

Abstract: An optical accessory comprises a bayonet type mount which can be freely mounted by rotation to a camera body having a camera mount of a bayonet type, a switch related to a power source and an operating member for actuating the switch. The optical accessory mount has a mounting claw arranged for pushing the operating member, the length of said mounting claw being so set that the mounting claw pushes the operating member for actuating the switch when the mounting by rotation of the optical accessory to the camera body is almost completed.

Abstract: A display device includes a display element which is arranged to have a plurality of electrode areas and to permit selective switchover between a transmitting state and a diffusing state by controlling an electric field, and a light emitting source which is arranged in such a position as to make an illumination color thereof visually confirmable only in an electrode area of the display element which is made into the diffusing state. The device is arranged such that displays can be provided adequately with a single light emitting source even when it is necessary to use a plurality of display parts for providing displays independently of each other.

Abstract: A memory device having a plurality of regions is provided with a designating circuit for performing data erasing and writing in a given memory region. A change circuit changes the memory region either after a predetermined number of erasing/writing cycles or in response to the number of times an operation member effects a detected state.

Abstract: A liquid crystal compound represented by the following formula; ##STR1## wherein R.sup.1 and R.sup.2 each represents an alkyl group having 3-20 carbon atoms, and X represents a group ##STR2## or --O--, or a single bond, and a liquid crystal composition exhibiting optically tristable states comprising the liquid crystal compound represented by the above formula and an antiferroelectric liquid crystal compound.

Abstract: Liquid crystal compound of the formula ##STR1## wherein R.sub.1 and R.sub.2 each is a C.sub.1-18 alkyl group or an aralkyl group, R' is haloalkyl group, X is --O--, --CO--, --COO-- or direct bond, Y is --COO--, --OCO-- or --CH.sub.2 O--, (A) and (B) each is ##STR2## and p and l each is zero or one.

Abstract: Antiferroelectric liquid crystal compounds are provided which have the formula ##STR1## wherein R.sub.1 represents an alkyl group having 5-18 carbon atoms,R.sub.

Abstract: An information input device for a camera includes an information member having first camera information displayed on one face thereof and second camera information displayed on a second face thereof, a holding member capable of holding the information member with either of its faces in viewable disposition and a detector for detecting which of the faces is in the viewable disposition when the information member is held by the holding member.

Abstract: Liquid crystal compound of the formula ##STR1## wherein R.sub.1 and R.sub.2 each is a C.sub.1-18 alkyl group or an aralkyl group, R' is a haloalkyl group, X is --0--, --CO--, --COO-- or direct bond, Y is --COO--, --OCO-- or --CH.sub.2 O--, (A) and (B) each is ##STR2## and p and l each is zero or one.

Abstract: A camera includes an automatic focusing device for focusing in a mode selected from different automatic focusing modes; an advancing device for advancing a film in a mode selected from different advance modes; an exposure device arranged to execute a program selected from different exposure programs; a storing device for storing information on the automatic focusing modes, the advance modes and the exposure programs in different combinations, each combination consisting of one of the automatic focusing modes, one of the feeding modes and one of the exposure programs; a setting device for setting one of selectable photographing modes; and a control device which is arranged such that, when a photographing mode is set by the setting device a photographing operation is allowed to be performed in applicable modes including in combination an automatic focusing mode, a feeding mode and an exposure program stored by the storing device.

Abstract: There is disclosed herein a ferroelectric liquid crystal electro-optical apparatus of the maxtrix type comprising a liquid crystal cell having first and second electrode substrates which include n striped line electrodes and m striped column electrodes, respectively, facing at right angles each other. A ferroelectric liquid crystal is put in therebetween so as to form n by m indication picture elements. Also included in the apparatus a scanning drive device adapted to supply a scanning signal and a data signal to the n striped line electrodes and the m striped column electrodes, respectively. The ferroelectric liquid crystal shows three stable states in accordance with an application voltage and has a light transmittance with a hysteresis sufficient to a dynamic drive in accordance with increase or decrease in the application voltage in a predetermined voltage range.

Abstract: Disclosed is a camera with a flash device, in particular, a camera with a flash device of the type in which charging of the flash device is suspended when a charged state of the flash device reaches a predetermined level. The above-described type of camera is characterized in that the charging of the flash device is not suspended immediately after the charged state of the flash device has reached the predetermined level but that it is suspended after the flash device has been further charged for a predetermined period of time.

Abstract: A power supply device in a camera system having an accessory arranged to be mountable and dismountable on and from a camera body which includes a power source. The camera body includes an electronic circuit arranged to communicate with the accessory by a first connection terminal arranged to permit a first power supply to the accessory, a second connection terminal arranged to permit a second power supply to the accessory, a third connection terminal arranged to permit communication with the accessory, and a detector for detecting mounting of the accessory on the camera body.

Abstract: A motor driven camera which includes a first motor, a film rewind drive mechanism for driving film in a rewinding direction by the first motor serving as a drive source, a second motor, a film windup drive mechanism for driving the film in the winding up direction by the second motor serving as a drive source, the film windup drive mechanism includes a planetary clutch arranged upon rotation of the second motor in one direction to bring a windup transmission system into connection with the second motor, and upon rotation of the second motor in another direction to take the windup transmission system out of connection, and a motor control circuit, receptive of a signal representing start of a film rewinding, for driving the first motor in the rewinding direction and the second motor in the other direction.

Abstract: An automatic focusing apparatus for a camera includes. The automatic focusing apparatus operated to drive a photographing lens to an in-focus position for an object upon a first operation of an operation member and to an in-focus position for another object upon a second operation of the operation member. Upon a third operation of the operation member, the lens is automatically driven to an intermediate position between the first and second positions, thereby simplifying lens driving for obtaining an in-focus state for the objects located at the different positions.

Abstract: A single-lens reflex camera having an automatic focusing capability, comprising a half-reflection mirror arranged in fixed relation to split part of light entering through the photographic lens to the finder optical system, a flippable submirror of total reflection arranged behind the mirror upon erection to direct part of the passed light to means for detecting the image sharpness, and control means responsive to termination of an operation of the detecting means for adjusting the size of opening of the diaphragm aperture and, at the same time, moving the submirror out of the path of the light from the mirror to the film gate, regardless of whether or not a shutter release is actuated.

Abstract: A power supply device in a camera system having an accessory arranged to be mountable and dismountable on and from a camera body which includes a power source. The camera body includes an electronic circuit arranged to communicate with the accessory by a first connection terminal arranged to permit a first power supply to the accessory, a second connection terminal arranged to permit a second power supply to the accessory, a third connection terminal arranged to permit communication with the accessory, and a detector for detecting mounting of the accessory on the camera body.