SU653518A1

SU653518A1 - Electronic exposure meter

Info

Publication number: SU653518A1
Application number: SU762308459A
Authority: SU
Inventors: Валерий Васильевич Быданов
Original assignee: Bydanov Valerij V
Priority date: 1976-01-04
Filing date: 1976-01-04
Publication date: 1979-03-25

Description

(54) ЭЛЕКТРОННОЕ ЭКСПОНОМЕТРИЧЕСКОЕ УСТРОЙСТВО(54) ELECTRONIC EXPONOMETRIC DEVICE

Изобретение относитс к фототехнике и может быть использовано в фотоаппаратах или в процессе фотопечати .The invention relates to photographic equipment and can be used in cameras or in the process of photo printing.

Известны электронные экспонометрические устройства, используемые в фотоаппаратах и в фотоувеличительных установках дл автоматического определени времени экспозиции фоточувствительных материалов , содержащее оптическую систему и схему преобразовани 1.Electronic exposure metering devices used in cameras and in photo-magnifying installations for automatically determining the exposure time of photosensitive materials are known, comprising an optical system and a conversion circuit 1.

Наиболее близким по технической сущности к предлагаемому устройству вл етс электронное экспонометрическое устройство, содержащее схему преобразовани и светодиоды 2.The closest in technical essence to the proposed device is an electronic exposure meter device comprising a conversion circuit and LEDs 2.

Однако известные устройства не. надежны в работе.However, the known devices are not. reliable in operation.

Целью изобретени вл етс повышение надежности устройства.The aim of the invention is to increase the reliability of the device.

Это достигаетс тем,что в известное электронное экспонометрическое устройство введены генератор импульсов , логическа схема ИЛИ-НЕ, инвертор и конденсатор, втора обкладка которого заземлена, причем один из входов схемы ИЛИ-НЕ подключен к генератору импульсов, а второй - к выходу инвертора, вход которогоThis is achieved by introducing a pulse generator, an OR NOT circuit, an inverter and a capacitor, the second plate of which is grounded, with one of the inputs of the OR circuit NOT connected to the pulse generator, and the second one to the output of the inverter, the input whom

соединен с конденсатором и через один из светодиодов с генератором импульсов, а вьосод схемы ИЛИ-НЕ и остальные светодиоды соединены со схемой преобразовани .connected to the capacitor and through one of the LEDs to the pulse generator, and the OR-NOT circuit video and the other LEDs are connected to the conversion circuit.

На чертеже дана структурна схема устройства.The drawing is a block diagram of the device.

Устройство содержит схему 1 преобразовани экспонометрических пара- : метров, индикаторные светодиоды 2, светодиод 3, работаюищй в режиме фотодатчика , генератор 4 импульсов, конденсатор 5, инвертор 6 и схему ИЛИНЕ 7.The device contains a circuit for converting the exposure meter: meters, indicator LEDs 2, a LED 3, operating in a photosensor mode, a generator of 4 pulses, a capacitor 5, an inverter 6 and the ORINE 7 circuit.

Claims

As indicator LEDs 2 and LED 3 operating in a photosensor mode, a common array of LED elements may be used, for example, an eight-element matrix of a synthesizing type LED indicator, in which one of the display-free segments, for example, is used for the photosensor. Common bus of all elements of the matrix .. connected to the generator 4 pulses. As inverter 6, a circuit with a high input resistance (on the order of lO-lO Ω) should be used. The device works as follows. When the appearance at the output of the generator 4 is zero. the potential begins to discharge the capacitor 5 through the reverse-resistance of the LED 3, the magnitude of the resistance of the latter depends on the magnitude of the incident luminous flux (as the luminous flux increases, the resistance decreases). As soon as the voltage level at the capacitor 5 reaches the threshold of the inverter 6, a high potential appears at its output, which leads to the disappearance of the signal at the output of the circuit 7 OR NOT. The pulse width at the output of circuit 7 OR-NOT depends on the magnitude of the inverse resistance of LED 3, i.e. ultimately, on the magnitude of the measured luminous flux. The impulse from the circuit 7 OR-NOT goes to the circuit 1 of the conversion of the exposure parameters, where, after appropriate processing, is recorded from the measuring or control signal in the form of a specific code. The latter enters the indicator LEDs 2. The displayed information can be represented both in the form of certain signals and in the form of a numerical value. As can be seen from the foregoing, before / laraeMoe, the device allows using the same and Tj LED matrix in two different modes, which creates technological and structural prerequisites for creating convenient in operation exposure meters. When using the proposed photometric imaging device, a photosensor located in the illuminated field of the photographic enlarger can be simultaneously used to indicate the recommended type of photo paper contrast (the latter can be determined by the maximum difference in the level of illumination on different elements of the LED matrix) and the exposure time. An electronic exposure meter device comprising LEDs and a conversion circuit, characterized in that, in order to increase reliability, a pulse generator, an ORI logic circuit, an inverter and a capacitor, the second plate of which is grounded, are introduced into it. NOT connected to the pulse generator, and the second to the output of the inverter, whose input is connected to the capacitor and through one of the LEDs with the pulse generator, the output of the OR-NOT circuit and the other LEDs are connected to the circuit azovani. Sources of information taken into account in the examination 1.Shanin Yu.V. Electronics in the photo. M., Energie, 1974, p. 7595.

2. Authors certificate of the USSR 425056, cl. G 01 J 1/00 ,. 1971.