Minolta Camera Kabushiki Kaisha

Kazuhiko Naruse

Yoshio Yuasa

Masahito Inaba

Nobukazu Kawagoe

Hidetoshi Yasumoto

Yoshihiro Okui

Hiroshi Furukawa

Naoya Takata

Norio Ishikawa

Takehiro Katoh

Masayasu Hirano

Yoshihiko Azuma

Akira Kataoka

Shinji Shimizu

Izumi Horie

Mikio Uematsu

Taketoshi Kawamura

A light measurement device includes a photoelectric converter for receiving light from an object to be measured and converting the light to a measuring electrical energy in accordance with the intensity of the light, an offset amount measurement device for measuring the offset amount of the photoelectric converter, temperature measurement device for measuring a first temperature of the photoelectric converter when measuring the offset amount, and a second temperature of the photoelectric converter when measuring the light from the object, a memory device for storing a characteristic of the photoelectric converter with respect to temperature, correction amount calculation device for calculating a correction amount based on the characteristic, the first temperature, and the second temperature, and a light intensity calculation device for calculating a light intensity based on the measuring electrical energy, the offset amount, and the correction amount.

Light measurement device

A device for measuring a luminance of a fluorescent screen of a cathode ray tube includes a photoelectric conversion device for receiving light from the fluorescent screen and converting the light to electrical energy, an integral device for integrating the electrical energy, a measurement device for measuring the glowing interval time of the cathode ray tube, and a control device for controlling the integral device so as to integrate the electric energy for a general integral time corresponding to the interval time. Also, this device has a calculation device for calculating an offset integrated electrical energy corresponding to a bias component of the photoelectric conversion device, another calculation device for calculating a true integrated electrical energy by subtracting the offset integrated electrical energy from the measured general integrated electrical energy.

Device for measuring luminance of fluourscent screen of cathode ray tube

An improved light measuring device for measuring flash light is provided, and includes a sensor for measuring the quantity of flash light to produce a flash measuring signal. A starting signal is produced upon a detection of the start of the flash emission to enable the sensor for measuring the quantity of flash light. The light measuring device is kept in an operative condition for a predetermined time period after it is manually turned on so that it is available to detect the start of any flash emission during that time period. A counter can be utilized to set the predetermined time period, and the counter can be reset in response to any light measuring operation.

Light measuring device

In a light source device in which one or more light emitting tubes are adapted to emit light sequentially, there are provided one or more counters for counting the number of times of failure of light emission of the light emitting tubes, and comparator or judging circuit for comparing the number counted by the counters with a predetermined number to produce an interruption signal when the counted number is over the predetermined value, a control unit acts to interrupt the light emission of the light emitting tube in response to the interruption signal and a warning device is activated for indicating a warning in response to the interruption signal.

Light source device

An improved optical signal receiving apparatus useful in optical communication is provided. Peripheral light can be measured and compared to determine if its intensity is above a certain predetermined level. The apparatus can display an indication when the measured intensity is over the predetermined level, such as through an emission at a predetermined wavelength.

Optical signal receiving apparatus with compensation for peripheral light

A photometer comprising a measurement button and a FIX key; a photoelectric conversion circuit which is actuated by the measurement button so as to start a measurement; a random-access memory which holds a measured light value, obtained through the measurement by the photoelectric conversion circuit, when the FIX key is operated; an accumulator which calculates deviation of a measured light value obtained through the measurement effected by the photoelectric conversion circuit from the measured light value held by the random-access memory; and a display element by which; (a) when the random-access memory is not holding a measured light value, a measured light value obtained through the measurement effected by the photoelectric conversion circuit is displayed, (b) when the random-access memory is holding a measured light value and the measurement button is out of operation, the measured light value being held is displayed, and (c) when the random-access memory is holding a measured light value and the measurement button is operated, the deviation obtained by the accumulator is displayed instead of the measured light values while the measurement button is in operation.

Photometer

An electronic flash device fires one or a pair of flash tube sequentially for continuous shooting photography with a motor driven photographic camera, for substantially continuous illumination or for sequential illuminations at intervals, as well as fire the flash tube a single time for one shot photography. The flash device is provided with a main capacitor and an auxiliary capacitor which selectively energize the flash tube or tubes. The auxiliary capacitor is charged by the main capacitor and discharged to energize the flash tube for a small amount of flash light and short-time restoration of the flash firing circuit. When a pair of flash tubes are employed, they are alternatively actuated for the sequential firing and one of them is actuated for the single time firing. The pair of flash tubes are coupled with each other through a commutation capacitor and switch elements for quick repetition of their firings.

Electronic flash device

An enlarger for copying a film is provided having two modes of operation. A first mode of operation permits preliminary adjustment of the focus of the lens system while the second mode of operation permits an actual exposure, the first mode of operation being inhibited during the actual exposure of the film in the second mode.

Enlarger for use in photography

A light measuring device for use in flash photography, which measures preliminary flash light and ambient light to obtain camera exposure information under a mixture of primary flash light and ambient light, there are provided light measuring means and means for displaying the result of the measurement in such a manner that the desired exposure information of the several positions of the photographic object can be displayed on a common scale so that the effect of the flash light, ambient light and the total light can be recognized in one glance.

An improved light measuring device that is capable of measuring light upon initialization from either a flash of light or a manual switch is provided. A sensor assembly can produce a light intensity signal and a change in the intensity of the light measured can be used to produce a first signal. A second signal can be produced by a manually operable member. A counter can be used to count the number of signals and to produce a preparing signal upon an initial signal counted and a start signal upon a subsequent signal counted. Measurement of the amount of light in the circuit can be initially enabled when the counting means counts the first signal and the actual light measurement can be started subsequently upon the counting means initiating a start signal. Various sequences of producing the pair of signals can be utilized to control the operation of the light measuring device.

An electronic flash device fires one or a pair of flash tubes sequentially for continuous shooting photography with a motor driven photographic camera, for substantially continuous illumination or for sequential illuminations at intervals, as well as fire the flash tube a single time for one shot photography. The flash device is provided with a main capacitor and an auxiliary capacitor which selectively energize the flash tube or tubes. The auxiliary capacitor is charged by the main capacitor and discharged to energize the flash tube for a small amount of flash light and shorttime restoration of the flash firing circuit. When a pair of flash tubes are employed, they are alternatively actuated for the sequential firing and one of them is actuated for the single time firing. The pair of flash tubes are coupled with each other through a commutation capacitor and switch elements for quick repetition of their firings.

An enlarger for use in photography capable of printing a color copy from a color original film includes a light source for generating a plurality of primary colors and a microcomputer for controlling the light source. The microcomputer has various functions which are: for providing a plurality of exposure data corresponding to a plurality of primary colors; for designating at least one of the primary colors; for altering the exposure data corresponding to the designated primary color; for displaying an information relating to the exposure data to be altered; for indicating the direction of change in tone of the color copy caused by altering the exposure data; for selecting the type of the original film; and for controlling the relation between the direction of change in tone of the color copy as indicated and the direction of change in the exposure data as displayed in response to the selected type of original film.

A color enlarger for use in photography capable of printing a color copy from a color original film includes a plurality of source lights for separately generating lights corresponding to a plurality of primary colors; a monitor for separately picking-up the plurality of source lights to monitor the light generated from the light source, and light measuring circuit for separately measuring the plurality of source lights transmitted through the color original film. The color enlarger further includes a microcomputer which has various functions which are: for providing a color data representative of a color to be reproduced on the color copy; for separately calculating the whole light quantities for the plurality of source lights to be generated upon printing the color copy, in response to the monitor, the light measuring circuit, and the provided color data; and for controlling light sources upon printing the color copy in response to the calculating value.

Color enlarger

Light source for exposure

In an instrument such as an electronic desk-top or pocket calculator, an exposure meter or the like, having a plurality of data-inputting switches in the form of a pushbutton switch, key switch, pressure or touch sensor switch, a control switch is provided for preventing inadvertent change of data stored or registered in the instrument. To this end, gates are interposed between the data inputting switches and a data storage member in the instrument. The instrument could alternatively include a microcomputer programmed to change its stored data in response to the operation of the input switches and to be prevented from changing the data upon operation of the control switch.

Growing community of inventors

Nabari, Japan

Kazuhiko Naruse