JPH03184027A - Camera with battery check device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a camera having a battery check device for detecting whether a power supply voltage is below a predetermined value.

B. Conventional technology Traditionally, for example, the power supply voltage (voltage of the power supply battery) is detected every time the release button is pressed halfway, and if the power supply voltage is below a predetermined value, it is determined that photography is not possible. Cameras that issue warnings are known. This allows the photographer to know when it is time to replace the battery, but by the time the warning is given, it is already impossible to take pictures, so if you do not have a new battery, there is nothing you can do about it, which is inconvenient. Met.

Therefore, a camera is known in which the battery check function has two stages, and a preliminary warning is issued before photographing becomes impossible, and a main warning is issued when photographing becomes impossible.

According to this, it is possible to know that the battery capacity is low before photographing becomes impossible, and measures such as preparing a new battery can be taken. Also, for example, JP-A-60-230
As disclosed in Publication No. 639 or Japanese Patent Application Laid-open No. 60-230640, there is also a camera that counts the number of shots taken, calculates the remaining battery capacity based on the counting result, and displays this in stages. Are known. According to this,
You can know the remaining battery capacity at any time, and as described above, you can take measures such as preparing a new battery when the capacity is running low.

Problems to be Solved by the C0 Invention However, what the photographer really wants to know is how many frames can be taken with the current remaining battery power, but the preliminary warning and remaining battery capacity display described above do not provide a rough idea. However, it was not possible to know specifically how many more shots could be taken, and it did not satisfy the essential needs of photographers.

A technical problem of the present invention is to enable the photographer to recognize how many more shots can be taken.

01 Means for Solving the Problems To explain with reference to FIGS. 1(a) and 1(b), which are diagrams corresponding to claims, the present invention provides a camera having a battery check device 101 that detects whether the power supply voltage is below a predetermined voltage. applied to.

The invention according to claim 1 includes a counting means 102 for counting the number of times of photographing as shown in FIG.
The camera is equipped with a frame number calculation means 103 for calculating the number of remaining frames that can be photographed with a newly loaded power supply battery, thereby solving the above technical problem.

Further, as shown in FIG. 1(b), the invention of claim 2 includes a counting means 201 for counting the number of times the photographing has been performed, a detecting means 202 for detecting the replacement of the power source battery, and a detection means 202 for detecting the replacement of the power source battery. When the power supply voltage is below a predetermined voltage, the camera is provided with a frame number calculating means 203 that calculates the remaining number of frames that can be photographed with a newly loaded power supply battery based on the number of times of photographing at that time.

80 Effect (1) Invention of Claim 1 The frame number calculation means 103 calculates the number of times of photographing (counted by the counting means 102) when the power supply voltage becomes below a predetermined voltage.
Based on this, the remaining number of frames that can be taken with the newly loaded power battery is calculated. This allows the photographer to know specifically how many more shots he or she can take.

(2) If the power supply voltage is below a predetermined voltage at the time of replacing the power supply battery, the frame number calculation means 203 of the invention according to claim 2 calculates the remaining number of newly loaded power supply batteries based on the number of shots taken at this time. Calculate the number of frames that can be photographed. This provides the same effect as described above.

F. Example 1.First embodiment- An embodiment of the present invention will be described with reference to FIGS. 2 to 5.

In FIG. 2 showing the overall configuration, 2o is a comparator 21. This is a battery check circuit consisting of resistors 22 and 23 and a reference power supply 24. The comparator 21 has a voltage obtained by dividing the power supply voltage (voltage of a power supply battery (not shown)) by a resistor 22, 23 and a reference voltage of a reference power supply 24 in a hexagonal manner. When the voltage becomes lower than the reference voltage, the comparator 21 outputs a low level signal. Here, the fact that the divided voltage becomes equal to or less than the reference voltage indicates that the power supply voltage has been consumed to a predetermined voltage or less, and photographing cannot be performed with that voltage.

The output signal of the comparator 21 is input to a control circuit 10 that controls the entire sequence of the camera.

This control circuit 10 includes a normal shooting counter 11 that counts the number of normal shootings that do not use an electronic flash device 30, which will be described later.
, a flash photography counter 12 that counts the number of flash photography using the electronic flash device 30, and a calculation section 13.

The control circuit 10 also includes an exposure control circuit 1 to which a shutter drive motor 2 is connected, an electronic flash device 30 having a light emission control circuit 31 and a light emitting tube 32, and an electronic flash device 30 that is turned on in conjunction with the operation of a release button (not shown). Switches SWI and SW2 are connected.

The exposure control circuit 1 drives a shutter (not shown) using the motor 2 in response to a command from the control circuit 10 to take a photograph.The light emission control circuit 31 controls the light emission in response to a light emission signal from the control circuit 10. The charge stored in the illustrated main capacitor causes the arc tube 32 to emit light. The switch SWI is turned on by pressing the release button halfway, and the switch SW2 is turned on by pressing the release button fully.

Next, the control procedure by the control circuit 10 will be explained using flowcharts shown in FIGS. 3 to 5.

When a main switch (not shown) is turned on, this program is started, and first in step S1 it is determined whether the above-mentioned half-press switch SWI is on.

If it is off, wait until it is turned on, and if it is turned on, proceed to step S2. In step S2, the output of the comparator 21 forming the battery check circuit 20 is read, and in step S3 it is determined whether the output is low level or not. However, if it is determined that the level is not low, the process advances to step S4. Here, the fact that the output of the comparator 21 is not at a low level indicates that the power supply voltage is higher than the predetermined voltage and photography is possible.

Step S4. In S5, the subject brightness and subject distance, which are the detection results of a photometric circuit and a distance measuring circuit (not shown), are input respectively (photometering process, distance measuring process), and then in step S6 it is determined whether the full-press switch SW2 is on. .

If it is off, it waits until it is turned on, and if it is turned on, it proceeds to step S7.

In step S7, focusing is performed based on the subject distance obtained in the distance measurement process, and an exposure value (aperture value, shutter speed) is calculated based on the subject brightness obtained in the photometry process, and the exposure control circuit 1 Shooting is performed by driving the aperture and shutter based on the calculated exposure value.
At that time, for example, if the obtained shutter speed is greater than or equal to a predetermined camera shake limit value, normal photography is performed without using an electronic flash device, and if the shutter speed is slower than the camera shake limit value, an electronic flash Perform flash photography using the device (that is, cause the arc tube 32 to emit light via the light emission control circuit 31)
.

Thereafter, in step S8, it is determined whether the photographing in step S7 is flash photography or normal photography. In the case of flash photography, the count value SN of the flash photography counter 22 is set in step S9.
Step S10 if the step is 1J and normal shooting is performed.
In step SLI, the count value NN of the normal shooting counter 21 is incremented by rll and the process proceeds to step SLI. In step SLI, the film is wound by one frame by a winding device (not shown), and then the process returns to step S1 and the above-mentioned processing is performed. Repeat.

Here, it is assumed that the count values SN and NN are set to zero when the power supply battery is loaded, and thereafter are stored even after the main switch is turned off.

On the other hand, in step S3 described above, the comparator 21
If it is determined that the output is at a low level, it is determined that the power supply voltage is below a predetermined value and photographing is not possible at that power supply voltage, and in this case, the battery capacity calculation process in step S12 is performed without photographing. Proceed to. Here, this step 312
shall be performed only when the first power battery is inserted after the camera is manufactured.

To explain with reference to FIG. 4 showing details of step S12,
First, in step 5121, the count value SN of the flash photography counter 12 (the number of internal light photography) is read out, and in step 5122, the count value NN of the normal photography counter 11 (the number of normal photography) NN is read out, and then in step 5123, the count value SN is read out.

Calculate the power consumption from all shooting from NN to the present. In other words, the power consumed by one flash photography is P
S, and the power consumed by one normal shooting is P) J.The power consumption pts by flash photography and the power consumption PTN by normal photography are.

P73=SNXPs ・+・ (1) PTN: NNX
PN...each is determined by (2).

Therefore, the power consumption PT for all imaging can be calculated as follows: P7=Prs+PTN-(3). Here, the process in FIG.
Since this process is performed only after the power supply voltage is determined to be below the predetermined voltage in step S3 in the figure, the power consumption PT calculated by the above equation (3) is determined by the actual capacity of the power supply battery used for photographing ( It can be thought of as the capacity when not in use). The reason why two actual capacities of the power source batteries are calculated in this way is as follows.

That is, although lithium batteries, which have been widely used in recent years, have little variation in their capacity, the reference voltage of the reference power supply 24 that constitutes the battery check circuit 20 described above varies depending on the camera. Even if used, the battery capacity PT used for photographing differs depending on the camera.

These two battery capacities are used to calculate the number of remaining frames that can be taken, which will be described later. However, when calculating with this capacity PT as a constant value, due to the above-mentioned variations, depending on the camera, an accurate number of frames cannot be calculated. I can't. Therefore, here, the camera, more specifically, the battery capacity P according to the reference voltage of the battery check circuit 20 used in the camera.
We are looking for T.

Next, the above-mentioned arithmetic processing will be explained using a specific example.

Now, the power Ps consumed by one flash photography is 2
(mAh), power P consumed by one normal shooting
M is 0.5 (mAh), the number of flash shots at the time when step S3 is affirmed is 400, and the number of normal shots is 400.
Suppose it was times.

According to this, the power consumption PTs for flash photography and the power consumption PTN for normal photography are calculated by the above equations (1) and (2).
) formula, PTS=400X2 (mAh)=800 (mAh)
PTN=400X0.5 (mAh)=200 (mA
h), and the power consumption for all shooting, that is, the actual capacity PT of the power battery according to the camera, is calculated by equation (3).

Py=800(mAh)+200(mAh)=1000
(mAh).

FIG. 5 shows the actual battery capacity P obtained by the process shown in FIG.
This is a process of calculating and displaying the remaining number of frames that can be photographed with the newly loaded power supply battery based on T. For example, after replacing the battery with a new one, this program
An interrupt is activated each time I is turned on. Note that it may be started by operating a separate switch.

In FIG. 5, step S21. In S22, the count value SN for flash photography and normal photography is determined, similar to steps 5121 and 5122 in FIG. 4 described above.

NN is read out 0 Next, the process proceeds to step S23, where the ratio rs of flash photography and the ratio rH of normal photography from the time when the new battery was loaded to the present are calculated using the number of times SN of both photography is performed.
, NN, and is determined by rH (%) = 100-rs - (5).

Next, in step S24, the above (1), (2), (3)
Power consumption P from new battery loading to present based on the formula
T□ is calculated, and then in step S25, the power consumption PTI calculated in step S24 and the above step 5 are
Actual capacity P of the power supply battery calculated in 123 (Figure 4)
Remaining battery capacity value P1 from T.

P1=Pr-PT,...(6) The process proceeds to step S26.

In step S26, the remaining number of frames that can be photographed is calculated from this remaining battery capacity value P4 and the ratio r8trN calculated in step S23. In other words, if we assume that the remaining number of frames that can be photographed is X and that photography will continue to be performed at the above ratio rs+rN, then
HXX = P1 holds, and from now on X = ... (7)
(PBX r3+PNX rH) The remaining number of photographable frames X can be calculated.

Here, each of the above calculations will be explained using a specific example.

Similarly to the above, the power p consumed by one flash photography
Assume that s is 2 (mAh), the power PN consumed by one normal shooting is 0.5 (mAh), and that from the time the new battery was loaded until now, flash photography has been performed 200 times, and normal photography has been performed 300 times. .

According to this, the power consumption pds for flash photography and the power consumption PTN for normal photography are calculated by the above equations (1) and (2).
) formula, Pt5=200X2 (mAh)=4oo (mAh)
Pt5=200X2.5 (mAh)=150 (mA
h), and the power consumption of 2 cameras for all shooting is calculated using the formula (3) % formula % () Also, the ratio r3 of flash photography and the ratio rH of normal photography to all photography are calculated using the above formula (4) and (5> By the formula.

rN (%) = 100-40 = 60 (%).

Here, the actual capacity PT of the power supply battery is determined as <10 as described above.
00 (mAh), the remaining battery capacity value Pl is (
6) According to the formula, P1 = 1000 (mAh) - 550 (mAh) = 45
0 (mAh), and therefore, according to equation (7), the remaining number of photographable frames X is as follows.

After calculating the remaining number of shootable frames X, step S2
7, the number of frames X is displayed on, for example, a liquid crystal display device via a display circuit (not shown).

According to the above procedure shown in FIG. 5, after loading a new power battery, for example, press the release button halfway (switch SWI
On), the number of flash photography and normal photography performed up to that point SN.

NN and the actual battery capacity Pt corresponding to the camera calculated in FIG. , the remaining number of frames X that can be photographed with the newly loaded power battery is calculated and displayed. Therefore, even if the reference voltage of the battery check circuit 20 differs depending on the camera, it is possible to accurately know how many frames can be photographed.

In addition, in this embodiment, the number of flash shots and the number of normal shots are both counted, and the remaining number of frames that can be shot is calculated based on the number of times the photographer takes flash shots and normal shots. Even if you do this, you can accurately know the remaining number of frames that can be photographed.

In the configuration of the above embodiment, the battery check circuit 20 controls the battery check device 101 and the control circuit 10
The counters 11 and 12 function as the counting means 102 and the calculation unit 13.
constitute the frame number calculation means 103, respectively.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. 6 and 7.

In the first embodiment described above, the actual capacity of the power supply battery is determined by the number of shots taken from the time the power supply battery is loaded until it is determined that the power supply voltage is below a predetermined value. If the power supply battery is replaced before the battery is replaced, the actual battery capacity Pr cannot be determined accurately. It is obvious that if this inaccurate battery capacity PT is used, the remaining number of frames to be photographed will also be inaccurate. This second embodiment eliminates this inconvenience by detecting battery replacement.

FIG. 6 is a configuration diagram of this embodiment, in which a switch SW3 is added to the configuration of FIG. 2.

The switch SW3 is a switch that is turned on and off in conjunction with the attachment and detachment of the power supply battery, and is turned off when the battery is loaded and turned on when the battery is removed.

In this embodiment, the program shown in FIG. 3 is started when the main switch is turned on, as described above.

If step S3 is affirmative, the process returns without performing step S12.

The program shown in FIG. 7 is started when the switch SW3 is turned on, that is, when the power supply battery is removed. It is assumed that this program is activated by the backup power source even after the power source battery is removed, and the output signal of the comparator 21 is maintained for a predetermined time even after the power source battery is removed.

First, in step S71, the output signal of the comparator 21 constituting the battery check circuit 20 is read, and then in step S72, it is determined whether or not the output is at a low level. If it is determined that the level is not low, both the count values SN and NN are reset to zero in step S73, and if it is determined that the level is low, the process proceeds to step S74, which is the battery capacity calculation process, which is the fourth step described above. This is the same process as shown in the figure. Here, the fact that the output of the comparator 21 is low level means that the power supply voltage is below the predetermined voltage.
Indicates that photography is not possible.

After loading a new battery, for example, press the half-press switch SW.
1 is turned on, the program shown in FIG. 5 described above is activated each time, and the remaining number of photographable frames X is calculated and displayed.

In other words, in the above procedure, if the voltage of the power supply battery is below a predetermined value when the power supply battery is removed, it is determined that the capacity of the battery has decreased to such an extent that photography is no longer possible, and the battery must be replaced. The capacity PT is calculated, but if the power supply voltage is higher than a predetermined value, it is determined that the battery will be replaced even though the battery capacity is high enough to allow photography, and the count values SN and NN are cleared. According to this, the battery capacity is calculated from the number of shots taken during that time only when the battery is not replaced even once from the time the battery is loaded until the battery capacity becomes equal to or less than a predetermined value. Therefore, an accurate battery capacity PT is required, and an accurate number of remaining frames
It becomes possible to obtain.

In the configuration of the above embodiment, the counters 11 and 12 function as the counting means 201, and the switch SW3 functions as the detecting means 202.
The calculation unit 13 constitutes a frame number calculation means 203, respectively.

Although the above description has been made of a camera with a built-in electronic flash device, the present invention can also be applied to a camera without an electronic flash device. In this case, each of the above calculations is performed using only the normal number of shots NN.

Furthermore, in the above, the actual battery capacity PT is determined and the remaining number of frames X that can be taken is calculated based on this.
The number of times of photographing (counted by counters 11 and 12) when the power supply voltage falls below a predetermined value depends on the above-mentioned substantial battery capacity PT.

It is also possible to directly determine the remaining number of frames that can be photographed based on this number of times of photographing and the number of times of photographing with a newly loaded battery.

Effects of the G9 Invention According to the invention of claim 1, the remaining number of frames that can be taken with a newly loaded power supply battery is calculated based on the number of shots taken when the power supply voltage becomes lower than the reference voltage. Even if the reference voltage of the battery check device differs depending on the camera, it is possible to determine and notify the number of frames remaining that can be photographed with the camera, thereby satisfying the essential needs of the photographer.

Furthermore, according to the invention of claim 2, when the power supply voltage is lower than the reference voltage when replacing the power supply battery, the remaining number of frames that can be taken with the newly loaded power supply battery is calculated, so that the above-mentioned In addition to obtaining the same effect as above, even if the battery is replaced before the power battery is exhausted, it is possible to accurately determine the number of remaining frames that can be photographed.

[Brief explanation of drawings]

Figures 1(a) and 1(b) are complaint correspondence diagrams. 2 to 5 show a first embodiment of the present invention. FIG. 2 is a block diagram showing the control system of the camera according to the present invention, and FIGS. 3 to 5 are flowcharts of the processing procedure. 6 and 7 show a second embodiment of the present invention, FIG. 6 is a block diagram of the control system, and FIG. 7 is a flowchart of the processing procedure. 10: Control circuit 11 Normal shooting counter 12:
Flash photography counter 13: Arithmetic unit 20: Battery check circuit 21: Comparator 22, 23: Resistor 24: Reference power source 30: Electronic flash device 101: Pantry check device 102.201: Counting means 103.203: Frame number calculation means 202 :Detection means

Claims (1)

[Scope of Claims] 1) A camera having a battery check device for detecting whether a power supply voltage is below a predetermined voltage, comprising: a counting means for counting the number of times an image is taken; 1. A camera having a battery check device, comprising a frame number calculation means for calculating the remaining number of frames that can be photographed with a newly loaded power supply battery based on the number of times of photographing when the number of photographs is reached. 2) A camera equipped with a battery check device that detects whether the power supply voltage is below a predetermined voltage, comprising: a counting means for counting the number of times an image is taken; a detection means for detecting replacement of the power supply battery; Frame number calculation means for calculating the remaining number of frames that can be photographed with a newly loaded power supply battery based on the number of photographs taken at that time, if the power supply voltage is below the predetermined voltage at the time of replacement. A camera having a battery check device characterized by: 3) Further comprising an electronic flash device, the counting means counts the number of flash photography using the electronic flash device and the number of normal photography not using the electronic flash device, and the frame number calculation means: 3. A camera having a battery check device according to claim 1, wherein the remaining number of frames that can be photographed is calculated based on both the number of times.