JPS6156496B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a battery voltage detection and imprint processing method in a camera equipped with a data imprinting device.

More specifically, the present invention relates to a detection method in which battery voltage is detected under a load of a light-emitting display or a load resistor equivalent to the light-emitting display, and a method of processing the detection results.

Recently, cameras have been developed that are equipped with a device that can imprint data onto a film by emitting light from a light-emitting display consisting of a 7-segment emitting diode or a liquid crystal display that displays a white outline, and a light-emitting lamp. For cameras with imprinting devices, it is extremely important that the imprinted data be clearly visible with appropriate exposure. As the battery voltage decreases, the light emitting characteristics deteriorate and it becomes impossible to obtain a sufficient amount of exposure. Therefore, the problem becomes how to detect the battery voltage to obtain the minimum necessary exposure amount and what to do with the processing after detection.

First, the set value of the detection voltage is empirically defined as follows based on the minimum required exposure amount, etc. That is, assuming that the light emission intensity at the normal battery voltage is 1, the voltage at which the voltage decreases and the light emission intensity becomes 1/2 is set as the detection comparison set voltage. Alternatively, another definition may be given as follows. That is, assuming that the forward current of the light emitting display body at the normal battery voltage is 1, the voltage at which the voltage decreases and the forward current becomes 1/2 may be set as the detection comparison set voltage. This is actually more convenient.

As described above, in a camera equipped with a data imprinting device, battery voltage detection is meaningless unless it is performed when the light-emitting display is under load. Therefore, the present invention is devised to detect the voltage when the imprinting function is activated, that is, at a timing synchronized with the signal that lights up the light-emitting display in conjunction with the trigger signal that turns off the shutter.

On the other hand, there are cases where you want to detect the battery status without turning off the shutter. For example, detection is performed at fixed time intervals.
In this case, since the light-emitting display cannot be made to emit light, a separate switch is installed to generate a signal to replace the shutter, and a trigger signal is generated as if the shutter had been turned off, creating a constant pulse width signal. Voltage detection is performed by driving a resistor that allows a current equivalent to that of the light-emitting display to flow, and by causing a voltage drop equivalent to that when the light-emitting display is made to emit light. It is preferable to perform this detection timing at the end of the lighting signal as much as possible.

When detection is performed using either of the above two detection methods, the previous state is maintained until the next detection. If the voltage is below the set voltage, the following two processes are performed as a battery life condition. One is that the light-emitting display does not light up even if the shutter is turned off. other 1
One is to display the battery life status on a display provided on the housing.

Hereinafter, an embodiment will be explained with reference to the drawings.

FIG. 1 shows the voltage-current characteristics of the light-emitting display, and when the current at the reference voltage V is set to 1, the voltage Vo at which the current becomes 1/2 is set as the detection comparison set voltage.

FIG. 2 is a block diagram of the battery voltage detection mechanism.A light-emitting display lighting control circuit is activated by a trigger signal from the shutter 1 or switch 2 to drive the light-emitting display or a resistor. The lighting control circuit 5 also performs time control to adjust the exposure amount in accordance with the film sensitivity. Further, 5 operates the detection signal generating circuit 6, and the detection signal operates the state holding circuit 7 of FIG. 2 at the falling edge as shown in the timing chart of FIG. 7 outputs a lighting prohibition signal so as not to light up the light-emitting display even if the shutter is turned off.

As described above, according to the present invention, when data is imprinted on a film, a state of insufficient exposure is quickly detected and a warning is given to replace the battery, and at the same time, it is ensured that imprinting will never be performed in a state of insufficient exposure. This feature is very effective and indispensable for cameras with data imprinting devices, since no mistakes will occur in the photos.

[Brief explanation of the drawing]

FIG. 1 shows the voltage-current characteristics of the light-emitting display.
FIG. 2 is a block diagram of the battery voltage detection mechanism. 1... Shutter, 2... Switch, 3... Trigger generation circuit by shutter, 4... Trigger generation circuit by switch, 5... Light emitting display lighting control circuit, 6... Detection signal generation circuit, 7... Status Holding circuit, 8... light emitting display, 9... resistor.
5 drives 8 when the signal is based on 3, and drives 9 when the signal is based on 4. FIG. 3 is a timing chart of each signal.

Claims (1)

[Scope of Claims] 1. In a camera with a data imprinting device including at least one light emitting element operated by a battery, a voltage detection resistor 9 connected to the battery and equivalent to the light emitting element; a lighting control circuit 5 that applies a signal with a constant pulse width corresponding to the light emitting display signal to the resistor without lighting the light emitting element; and a lighting control circuit 5 that detects and detects a voltage generated at a terminal of the resistor based on the signal. It consists of a detection signal generation circuit 6 that generates a signal, and a display that displays the end of battery life based on the detection signal of the detection signal generation circuit, and the detection timing of the detection signal generation circuit is set at the timing of the signal of the constant pulse width. A camera characterized in that its rise is delayed by a predetermined time. 2. In a camera with a data imprinting device that includes at least one light-emitting element operated by a battery, a voltage detection resistor 9 connected to the battery and equivalent to the light-emitting element, and lighting the light-emitting element. a lighting control circuit 5 that applies a signal with a constant pulse width corresponding to the light-emitting element indicating signal to the resistor without any interference, and a lighting control circuit 5 that detects the voltage generated at the terminal of the resistor based on the signal and generates a detection signal. It consists of a detection signal generation circuit 6 and a state holding circuit that outputs a prohibition signal for prohibiting the operation of the light emitting element based on the detection signal of the detection signal generation circuit, and the detection timing of the detection signal generation circuit is set as described above. A camera characterized in that the rise of a signal with a constant pulse width is delayed by a predetermined time.