JPS5834423Y2 - Hiyoji Kairoo Sonata Denshi Shutter - Google Patents

Description

[Detailed Description of the Invention] The present invention is a camera equipped with a display circuit that displays high and low subject brightness and power supply voltage. Concerning what one chooses to do.

This type of IC has already been proposed and has the advantage of requiring only one display member, but the 0 changeover switch is complicated because multiple types of display are performed using one display member.

FIG. 1 shows one of the conventional circuits like this.

In this figure, 1 is usually 0 electronic shutter circuit, which includes a photoconductive element 2, a capacitor 3, a brightness detection resistor 4, an NPN (NPN) constituting a Schmitt circuit, transistors 5, 6, and resistors 7, 8,
It is removed from the shutter control magnet L-9, etc.

10 is a switch that is opened in conjunction with the opening of the shutter, and 11 is a switch that is opened before the shutter is opened and closed immediately before the shutter is opened.

12 is a light emitting diode or other indicator lamp (PNP) transistor 13, resistor 14, 15, changeover switch 16j7
Together with the battery checker circuit, 1 and 18 are resistors that regulate the current of the transistor 13, and 19 is a power switch.

In the above circuit, the changeover switches 16 and 17 are placed on the contact a side, and are manually switched to the contact side when performing a battery check.

First, the case of normal photographing operation will be explained.

At this time, switches 16 and 17 are on the contact a side, and when you press the overseas shutter button, first switch 19 is closed and then R
'L, at this stage, the switch 10 is closed and the switch 11 is open, and the voltage of the power supply 20 is applied to the base of the transistor 5 to the photoconductive element 2.
A voltage divided by and resistor 4 is applied, and the inversion potential of the Schmitt circuit made up of transistors 5 and 6 is set so that when the subject is, for example, above the camera shake limit with respect to the shutter speed, transistor 5 becomes conductive and transistor 6 is cut off. When the brightness of the field is below the limit of camera shake, transistor 6 is conductive, so transistor 13 is also conductive and lamp 12 is lit, indicating that the brightness of the field is below the limit of camera shake. Display warning.

When the shutter button is pressed further, the switch 11 closes and the transistor 5 is cut off regardless of the brightness of the outside world.
6 becomes conductive, magnet 9 is excited, and then, at the same time as the shutter opens, switch 10 is opened to start charging the capacitor 3, and when the charging voltage reaches a certain level, transistor 5 becomes conductive, and transistor 6 becomes conductive, and transistor 6 becomes conductive. The magnet 9 is de-energized and the shutter is closed.

Since the transistor 6 is conductive until the shutter is closed after the switch 11 is closed, the lamp 12 is lit, and the lighting of the lamp 12 in this case indicates that the shutter is open. .

A switch 21 is inserted in series with the lamp 12, and is closed when the shutter button is not pressed.This switch 21 is opened when the shutter button is pressed, but when the magnet 9 is energized at this time, it is held in the closed position. If the field is bright, the magnet 9 will not be excited when the shutter button is pressed and the field brightness measurement stage will open, so the switch 21 will open and the lamp 12 will not light up even during shutter operation. good.

Next, the case of battery check will be explained.

At this time, switch 16 and 17 are switched to the contact side.

In this way, a voltage obtained by dividing the voltage of the power supply 20 by the resistor 14.15 is applied to the base of the transistor 13.

By setting the resistors 14 and 15 so that this divided voltage has a value that makes the transistor 13 conductive when the voltage of the battery 20 is equal to or higher than a value that can be considered normal, when the lamp 12 is lit, the voltage of the power source battery 20 is Appears to be healthy.

In the above circuit configuration, switches 16 and 17 are required for switching between exposure display and battery check, but these switches constitute a double-pole, double-throw switch and are complicated.

In the present invention, a single open/close switch (single pole, single throw) is sufficient in place of the switches 16 and 17.

Next, the present invention will be explained with reference to examples.

FIGS. 2 and 3 each show an embodiment of the present invention.

Those with the same operations and functions as those in FIG. 1 are given the same reference numerals.

The electronic shutter circuit 1 is shown as a block, and its internal parts are not shown.

In FIG. 2, in the base circuit for transistor 13, a resistor 18 and a diode 22 are inserted between the base of transistor 13 and the collector of transistor 6, and a resistor 18 and a diode 22 are inserted between the connection point of resistors 14 and 15 and the base of transistor 13. A diode 23 is inserted, and a diode OR circuit is formed by the diodes 22 and 23.

A single-pole, single-throw switch 24 is inserted in the series circuit of resistors 14,15.

This switch is closed manually only when checking the battery.

In FIG. 3, diode 23 is omitted. The operation of displaying a camera shake limit warning using the circuit shown in FIG. 2 will be explained.

At this time, the shutter button is pressed by the photographing operation and the switch 19 is closed, so the transistor 6 is conductive and its collector is at a low level, so the base of the transistor 13 is also at a low level via the diode 22, and the transistor 13 is conductive. Then, the lamp 12 lights up.

At this time, the potential at the connection point between resistors 14 and 15 is at a high level because switch 24 is open, but since a voltage is applied in the opposite direction to diode 23, resistor 1
No current flows from 4 to the base of transistor 13.

The next time the battery is checked, the switch 24 is closed.

In this case, since the shutter button is not pressed, the switch 19 remains open, and the voltage of the power supply 20 appears as it is at the collector of the transistor 6, but this voltage is blocked by the diode 22, and the voltage at the connection point of the resistor 14. is applied to the base of the transistor 13 through the diode 23, and the state of the battery is indicated by whether or not the lamp 12 is lit in the same way as in the case of FIG.

In FIG. 3, the diode 23 is further omitted from the example in FIG. 2.

First, to explain the case of exposure display, when the outside world is dark and the transistor 6 is conductive, the collector current of the transistor 6 flows through the magnet 9, the resistor 14, 18, and the diode 2.
If the resistance value of the resistor 14 is made sufficiently larger than the resistance of the magnet 9, the voltage at the connection point between the resistors 14 and 18 will drop without any problem in excitation of the magnet 9. conducts and lamp 12
lights up to warn you of the limit of camera shake.

When checking the battery, the switch 24 is closed, but the switch 19 remains open, so the collector of the transistor 6 of the shutter circuit is at the power supply voltage, and the ratio of the sum of the resistors 14 and 18 and 15 is determined appropriately. By doing so, the health or unhealthiness of the power source battery is displayed in the same manner as explained in FIG.

The present invention has the above-mentioned configuration, and the power switch 19 of the shutter circuit is closed only when the shutter button is pressed, and when it is normally open, the output of the shutter circuit to the display circuit is normally at the same high level as the power supply voltage. Using diode 22, resistor 14. is used to check the battery.
15 is prevented from being connected to the electronic shutter circuit, and in the case of exposure display, the photometry result is applied to the display circuit through this diode. In the end, the switches 16 and 17 in the conventional example could be replaced with just 24 open/close switches, which reduces the causes of failure in the switch parts and improves reliability. Increased sex and switch 24
Since the switch is structurally simpler and smaller than a double-pole double-throw switch, it greatly contributes to the miniaturization of cameras.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an example of a conventional electronic shutter display circuit, and FIGS. 2 and 3 are circuit diagrams showing embodiments of the invention. 2.4, 10: Photometric circuit, 5-8 level judgment circuit,
12: Light emitting display element, 13: Transistor, 14, 15
, 18: Voltage divider, 19: Power switch, 20: Camera power supply, 22: Diode, 24: Battery check switch.

Claims (1)

[Scope of utility model registration request] A photometric circuit that outputs a voltage signal at a level corresponding to the subject brightness incident on the photodetector, and a high-level or low-level voltage signal depending on whether the voltage level output from the photometric circuit has reached a predetermined level. a level determination circuit that outputs a level determination circuit; a power switch that is opened and closed by manual operation to supply camera power to the photometric circuit and the level determination circuit; and an output level of the level determination circuit that is applied to the base; a transistor whose conduction or cutoff is controlled depending on its level; a light emitting display element which is connected in series to the camera power supply via the transistor and which emits light when the transistor is turned on and turns off when the transistor is turned off; an output terminal of the level determination circuit; Batch 1-check, which is closed by turning on and off the power supply voltage of the camera power supply;
The switch is directly connected to the camera power supply through the switch, and when the battery check switch is closed, the divided voltage of the camera power supply voltage is set to 1. 1. A display device for a camera, comprising: a voltage divider for outputting a voltage, and a voltage dividing point of the voltage divider connected between the base of the voltage divider and the diode.