JPH09113951A - Power source device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the high voltage and large capacity and current from the device, to perform the restoration of the device by only the exchange of a battery which is obtainable with ease and at low cost when the battery is consumed, and to gurantee photographing of a certain number of sheets of photograph film without exchanging an auxiliary battery. SOLUTION: Power is supplied to a power consuming means in a camera from a main battery 20, and the main battery 20 is charged to be kept in a necessary charged state by a charge circuit 40 by setting the auxiliary battery 30 such as a SUM3 dry battery as a charging power source. The residual quantity of electricity of the battery 30 is displayed on a liquid crystal panel 50 and the number of sheets of photographing feasible film is also displayed based on the quantity of electricity remaining in the battery 20 after the battery 30 is consumed up. When the auxiliary battery is consumed up, only the auxiliary battery which is obtainable with ease and at low cost is just required to be exchanged. Even when the battery 30 is consumed up, the camera can be used until the battery 20 is consumed up. Since the number of sheets of photographing feasible film without exchanging the auxiliary battery is grasped according to displayed contents on the panel 50, a user feels at ease.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for a camera, and more particularly to a power supply device for a camera suitable as a power supply for the camera.

[0002]

2. Description of the Related Art As a power source of a conventional camera, there are a case where a primary battery is used as a power source and a case where a secondary battery is used as a power source. Further, a power supply device for charging a secondary battery incorporated in a camera using a solar battery as an auxiliary battery has also been proposed (Japanese Patent Laid-Open No. 63-63119).
-91641).

[0003]

However, in the case of a camera using a conventional primary battery as a power source, a manganese-based primary battery has a low voltage, and thus a plurality of batteries are required to obtain a high voltage. Further, since it is difficult to obtain a large capacity current, there is a problem that the charging time of the strobe becomes long and it is not suitable for a recent camera having a zoom motor or the like that consumes a large current. In contrast, lithium-based 1
The secondary battery can obtain a high voltage and a large capacity current, but it has been pointed out that the battery becomes expensive and environmental problems at the time of disposal. Further, when the battery is exhausted, there is a problem that it is necessary to either stop using the camera or carry a spare battery until the battery is replaced with a new battery, which is complicated. Incidentally, the lithium-based primary battery may not be easily available at travel destinations or overseas. On the other hand, in the case of a camera using a conventional secondary battery as a power source, there are many restrictions on the charging method and attention is required to overcharging and overdischarging, so an expensive dedicated charging device is required. Also, in secondary batteries such as NiCd batteries, self-discharge is high (self-discharge rate is 5
(10% / month), the capacity decreases when not used for a long period of time, so that it may be necessary to recharge each time, or sometimes the battery may be over-discharged and deteriorated, making reuse impossible. Further, it was necessary to give up the use of the camera or carry a spare battery while charging the secondary battery.

Further, in a power supply device having a solar cell, the solar cell itself is expensive and it is necessary to expose the camera to high illuminance at the time of charging, so that the temperature of the camera may rise and the camera may break down. Further, when the secondary battery is rapidly consumed, the amount of electric power generated by the solar cell is small and it takes a long time to charge, so that there is a problem that the camera cannot be used.

The present invention has been made in view of the above circumstances and is capable of supplying a high voltage, a large capacity, and a large current, and at the time of exhaustion of a battery, only an inexpensive and easily available auxiliary battery is replaced. It is also an object of the present invention to provide a power supply device for a camera that allows a certain degree of photography without replacing the auxiliary battery and provides a sense of security.

[0006]

In order to achieve the above-mentioned object, the present invention comprises a rechargeable main battery for supplying electric power to a power consuming means in a camera, and an auxiliary battery accommodating portion to which an auxiliary battery can be attached and detached. It operates every time the voltage of the main battery reaches a predetermined lower limit value or each time the power of the main battery is consumed by a predetermined amount, and charging energy is charged from the auxiliary battery to the main battery until the main battery is fully charged. And a display unit for displaying the remaining battery level of the auxiliary battery and for displaying the number of images that can be taken according to the amount of electricity remaining in the main battery after the auxiliary battery is exhausted. I am trying. As a result, when the auxiliary battery is consumed, only the inexpensive and easily available auxiliary battery (for example, AA type dry battery) needs to be replaced, which is more economical and environmentally friendly than the case of replacing the main battery. . In particular, by using a metal lithium secondary battery as the main battery, a large capacity and a large current can be supplied from the main battery to the device, and since there is little spontaneous discharge, the device can be used even when it is not used for a long time. can do.

Further, the charging means operates every time the voltage of the main battery reaches a predetermined lower limit value or each time the power of the main battery is consumed by a predetermined amount, and the main battery is operated by the main battery until the main battery is fully charged. The charging energy is supplied to the battery, and the display means displays the battery remaining amount of the auxiliary battery and also displays the number of photographable images according to the amount of electricity remaining in the main battery after the auxiliary battery is consumed. . This allows
Charging energy is supplied from the auxiliary battery to the main battery according to the power consumption of the main battery, and the main battery is always kept in a charged state. Therefore, there is no fear of over-discharge deterioration and the like, and the handling is easy. Also, even if the auxiliary battery is exhausted, the main battery is still in a charged state, so the camera can be used until the main battery is exhausted, and in particular, the contents displayed on the display means enable photographing without replacing the auxiliary battery. You can get a sense of security because you can grasp the maximum number.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a power supply device for a camera according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a front view including an internal perspective view of a camera including a power supply device for a camera according to the present invention. In the figure,
Reference numeral 10 is a power supply device, 12 is a taking lens, 14 is a viewfinder, and 16 is a strobe.

The power supply device 10 is mainly composed of the main battery 2
0, the auxiliary battery 30 is composed of an auxiliary battery housing 32 to which the auxiliary battery 30 is attachable and detachable, and a charging circuit 40. And the main battery 20
Power is supplied to the strobe 16, motors such as a zoom motor and a film feeding motor, and a camera control circuit. The main battery 20 is a battery exclusively for a rechargeable camera with little self-discharge, and has a self-discharge rate of 5 for example.
% / Year is used, and the voltage is 3.2V when properly charged.

Next, the details of the main battery will be described.
Manganese dioxide is preferable as the positive electrode active material of the main battery, and manganese dioxide synthesized by electrolysis and manganese dioxide chemically synthesized are particularly preferable. As a material that can be used as the negative electrode active material, lithium metal and lithium alloy (any metal that forms an alloy with lithium may be used, but Al, Mn, Sn, Mg, Cd, and In are particularly preferable, and an alloy containing Al is particularly preferable). Preferably, it is used.

A conductive agent, a binder, a filler and the like can be added to the electrode mixture. The conductive agent may be any electronic conductive material that does not cause a chemical change in the configured battery. The addition amount is not particularly limited,
It is preferably from 1 to 50% by weight, particularly preferably from 2 to 30% by weight. As the binder, a polysaccharide, a thermoplastic resin, a polymer having rubber elasticity, or a mixture thereof can be used. The amount of the binder added is not particularly limited, but is preferably 1 to 50% by weight, and particularly preferably 2 to 30% by weight.

As the filler, any fibrous material which does not cause a chemical change in the constructed battery can be used. Usually, fibers such as olefin-based polymers such as polypropylene and polyethylene, glass, and carbon are used. Although the amount of the filler is not particularly limited,
-30% by weight is preferred. The non-aqueous electrolyte is generally composed of a solvent and a lithium salt (anion and lithium cation) dissolved in the solvent, and comprises propylene carbonate and / or butylene carbonate and 1,2-dimethoxyethane and / or diethyl carbonate. LLCF ₃ SO ₃ in a mixture of Kaponeto, LiCl0 _4, LiBF ₄ and / or an electrolyte containing LiPF ₆ is preferred. The amount of these electrolytes to be added to the battery is not particularly limited, but may be used in a required amount depending on the amounts of the positive electrode active material and the negative electrode active material and the size of the battery.

The volume ratio of the solvent is not particularly limited,
In the case of a mixture of propylene carbonate and / or butylene carbonate to 1,2-dimethoxyethane,
0.4 / 0.6 to 0.6 / 0.4 is preferred. The concentration of the supporting electrolyte is not particularly limited, but may be 0.1 to 1 liter of the electrolytic solution.
2-3 moles are preferred. Further, the auxiliary battery storage portion 32 shown in FIG. 1 is formed so that, for example, one AA type dry battery can be stored therein, and the auxiliary battery storage portion 32 stores an AA type dry battery as the auxiliary battery 30. It Note that another battery (secondary battery) may be stored as an auxiliary battery as long as it has the same shape as the AA battery.

The charging circuit 40 is composed of a charging control circuit 42 and a boosting circuit 44 as shown in FIG. The charge control circuit 42, respectively detects a voltage V ₂ of the voltages V ₁ and the auxiliary battery 30 of the main battery 20, for example, a voltage V _CR of the main battery 20, V _CR <3.0 V, and the and the voltage of the auxiliary battery 30 V _{When E} is V _E ≧ 0.9 V (the final voltage of the auxiliary battery 30), the booster circuit 44 is operated to charge the main battery 20.

On the other hand, the charge control circuit 42 operates when the main battery 20 is fully charged (when the voltage V _CR = 3.2 V).
Or the auxiliary battery 30 is exhausted, and the voltage V of the auxiliary battery 30
_{When E} becomes V _E <0.9 V, the booster circuit 44 is stopped. Furthermore, the charging control circuit 42 is configured to operate the auxiliary battery 30.
A signal indicating the voltage of the auxiliary battery 30 is output to the display control circuit 52 provided on the camera side in order to display the remaining battery power and the like on the liquid crystal panel 50. The details of the display contents of the liquid crystal panel 50 will be described later. The charging control circuit 42 is supplied with drive power from the main battery 20.

Next, the booster circuit 44 will be described. FIG. 3 is a circuit diagram showing an embodiment of the booster circuit 44. As shown in the figure, the booster circuit 44 is of a push-pull type, and the power supply of the auxiliary battery 30 is alternately turned on by the charge control circuit 42.
1. Convert to AC in Q2, boost through transformer T,
The main battery 20 is rectified by the rectification circuit 45.
Is converted to a DC voltage required for charging.

When the number of turns on the primary side and the secondary side of the transformer T is n _{1 and} n ₂ , the voltage V on the primary side of the transformer T is
The relationship between ₁ and the voltage V ₂ on the secondary side has the following formula: V ₁ / V ₂ = n ₁ / n ₂ (1) On the other hand, the voltages V ₁ and V ₂ required on the primary side and the secondary side of the transformer T are: V ₁ = 0.9−V _DS = 0.7 [V] (Min) (2) V ₂ = 3.2 + 0.7 × 2 + 0.5 = 5.1 [V] (3) (However, 0.9: Final voltage of auxiliary battery 30 V _DS : Saturation voltage between drain and source of transistors Q1 and Q2 3.2: Maximum voltage of main battery 0.7 × 2: Voltage drop in the rectifier circuit 45). Therefore, the turns ratio n ₂ / n ₁ of the transformer _{T, n 2 / n 1 = V} 2 / V 1 ≒ 7.3 ... (4) become.

Thus, the charging circuit 40 transfers the charging energy of the auxiliary battery 30 to the main battery 20 and charges the main battery 20 every time the voltage V _CR of the main battery 20 becomes V _CR = 3.0V. , When the main battery 20 is fully charged (voltage V _CR = 3.2
V), the charging operation is stopped. Fig. 4 shows auxiliary battery 3
7 is a graph showing how the charging energy of 0 is transferred to the main battery 20, the solid line shows the capacity of the main battery 20, and the alternate long and short dash line shows the capacity of the auxiliary battery 30.

As shown in this graph, the capacity when the main battery 20 is fully charged and the capacity of the new auxiliary battery 30 are substantially equal, and thereafter, the capacity of the main battery 20 is gradually reduced by using the camera. To do. When the voltage V _CR of the main battery 20 becomes V _CR = 3.0V, the charging energy of the auxiliary battery 30 is transferred to the main battery 20, so that the main battery 2
The capacity of 0 increases and the capacity of the auxiliary battery 30 decreases.

In this way, the charging energy of the auxiliary battery 30 depends on the amount of electricity consumed by the main battery 20.
The main battery 20 is always kept in a charged state of 3.0 V or more. As a result, there is no fear of over-discharge deterioration of the main battery 20, and handling is easy. Further, since the main battery 20 is a lithium-based battery, it can supply a high voltage and a large current to the camera as compared to the auxiliary battery 30, and it can be applied to a camera that requires a large current and the strobe charging time can be increased. It can be shortened.

Now, when the charging energy of the auxiliary battery 30 is transferred to the main battery 20 and the capacity of the auxiliary battery 30 reaches almost 0 as shown in FIG. 4, (the voltage of the auxiliary battery 30 reaches its final voltage 0.9V). When it reaches), then the auxiliary battery 30
Unless the battery is replaced, the charging energy cannot be supplied from the auxiliary battery 30 to the main battery 20. However, since the voltage V _{CR of} the main battery 20 is maintained in the charged state of 3.0 V ≦ V _CR ≦ 3.2 V, the voltage V _CR reaches a predetermined battery check level (BC level in FIG. 4). Up to a certain amount, there is a certain amount of consumable electricity (for example, an electricity amount capable of shooting 100 shots). Therefore, the camera can be continuously used without immediately replacing the auxiliary battery 30 with a new one.

Also, when replacing the auxiliary battery 30, since the auxiliary battery 30 may be an AA type dry battery, it can be easily obtained at low cost anywhere in the world. In addition, used AA batteries can be used to some extent. In the above embodiment, the voltage V _CR of the main battery 20 is V _CR = 3.
Although the charging energy of the auxiliary battery 30 is transferred to the main battery 20 when the voltage reaches 0 V, the charging energy of the auxiliary battery 30 is not limited to this when the number of shots reaches a predetermined number (for example, 100 shots). It may be transferred to the battery 20, and in this case, the charge control circuit 42 needs to receive a signal indicating the number of shots from the camera side.

Next, the liquid crystal panel 50 and the display control circuit 52 shown in FIG. 2 will be described. Display control circuit 52
Is the auxiliary battery 30 from the charging control circuit 42 as described above.
The signal from the film counter indicating the remaining amount of the film, the signal from the strobe switch, the shutter button, and the self-timer switch are added to the liquid crystal panel 50 based on these input signals. Display the required display.

That is, the display control circuit 52 determines the remaining battery level of the auxiliary battery 30 based on the signal indicating the voltage of the auxiliary battery 30 applied from the charging control circuit 42.
0 is displayed. 5A and 5B show a liquid crystal panel 50 showing an example of display contents of the liquid crystal panel 50.
2A is a plan view of the same, FIG. 7A shows the case where there is a battery remaining amount, and FIG. 7B shows the case where there is no battery remaining amount. As shown in these drawings, when there is a battery remaining amount, the remaining battery amount is displayed graphically on the display unit 50A of the liquid crystal panel 50 as shown in FIG. As shown in FIG. 5B, the display section 50A is blinked to prompt the user to replace the battery, and thereafter, the number of images that can be taken without changing the battery is displayed on the display section 50B.

That is, as described with reference to FIG. 4, the auxiliary battery 3
Even if 0 is consumed, the main battery 20 has a certain amount of consumable electricity (for example, an electricity amount capable of shooting 100 shots). Therefore, when the auxiliary battery 30 is consumed, for example,
As shown in FIG. 5A, the number of shootable images “99” is displayed on the display unit 50B, and then the number of shootable images is counted down by 1 for each shot.

Further, on the liquid crystal panel 50, the remaining film amount is displayed on the display section 50C so that the number of photographable images and the remaining film amount are not confused with each other.
Further, although not shown in FIG. 5, the liquid crystal panel 5
In 0, other necessary information such as flash photography and self photography is also displayed. The method of displaying the number of photographable images is not limited to the above-described embodiment, and for example, the voltage of the main battery 20 may be detected and displayed based on the voltage. Further, the display of the number of images that can be taken is not limited to numbers, but may be displayed graphically so that the approximate number of images can be recognized.

Next, another example of the arrangement of the power supply device of the camera according to the present invention in the camera and the battery replacement method will be described. 6 and 7 are respectively a top view and a front view including an internal perspective view of a camera including a power supply device for a camera according to the present invention. The same reference numerals are given to the same parts as those in FIG. 1, and the detailed description is omitted.

Comparing the power supply device 10 of FIG. 1 with the power supply device 60 of FIG. 6 and FIG. 7, the former has a substantially L-shape and is arranged in the camera, while the latter has a rectangular parallelepiped shape. They differ in that they are compactly arranged and arranged on the side of the camera. That is, as shown in FIG. 6, the power supply device 60 is divided into two parts by the partition plate 62, the auxiliary battery housing part 32 in which the auxiliary battery 30 is attachable / detachable is formed on one side, and the charging circuit 40 is formed on the other side. Is stored in the main battery 2 at the bottom
0 is stored (see FIG. 7).

The auxiliary battery housing 32 is provided with a battery lid 64 that can be opened and closed by a hinge 64A. By opening the battery lid 64, the auxiliary battery 30 can be easily replaced. On the other hand, the main battery 20 does not need to be replaced in the first place, and it is impossible or difficult for the user to take it out. That is, in order to replace the main battery 20, it is necessary to open the battery cover 64 and remove the partition plate 62, but this partition plate 62 cannot be removed without using a special jig. .

Therefore, the user does not have to be aware that the camera uses a rechargeable battery, and the AA type dry battery (auxiliary battery 3
0) There is an advantage that it is easy to handle because it can be recognized as a camera that can be driven by one camera. Further, the battery does not need to be replaced for about 600 shots from the beginning of use of the camera, and about 5 AA dry batteries can be replaced by 2000 shots, which is very economical. Furthermore, lithium battery (main battery 20)
Is cheaper than an ordinary secondary battery and has less natural discharge, so that it has an advantage that it can be photographed anytime without using it for a long time.

FIG. 8 is a perspective view showing another embodiment of the power supply device for a camera according to the present invention. The same parts as those of the power supply device 60 shown in FIGS. 6 and 7 are designated by the same reference numerals, and detailed description thereof will be omitted. Comparing the power supply device 10 of FIGS. 6 and 7 with the power supply device 70 of FIG. 8, it is different in that the former is integrally arranged in the camera, while the latter is configured as a single battery pack. To do.
Therefore, in the power supply device 70 of FIG. 8, the power supply output terminal 72 for supplying electric power from the main battery 20 is provided in the outer case.

The power supply device 70 can be used by being built in the battery housing portion of the camera or by being externally attached to the camera. The arrangement of the power supply device of the camera in the camera is not limited to the above embodiment,
Various forms are possible, and the charging circuit may be mounted on a circuit board in the camera. Further, in the embodiment of the present invention, the number of main batteries and auxiliary batteries of the power supply device is one, but the number of batteries is not limited to this. Further, the liquid crystal panel and the display control circuit may be provided not only on the camera side but also on the power supply device side.

[0033]

As described above, according to the power supply device for a camera of the present invention, the power is supplied from the main battery to the camera, and the main battery is charged by the auxiliary battery such as AA dry battery. When the power source (auxiliary battery) is consumed, only the inexpensive and easily available auxiliary battery needs to be replaced, which is more economical and environmentally friendly than the case of replacing the main battery. In particular, by using a metal lithium secondary battery as the main battery, a large capacity and a large current can be supplied from the main battery to the device, and since there is little spontaneous discharge, the camera can be used even when it is not used for a long time. can do.

Further, since the charging energy is supplied from the auxiliary battery to the main battery in accordance with the power consumption of the main battery so that the main battery is always kept in the charged state, there is no fear of over-discharge deterioration and the handling is easy. Since the main battery is still in the charged state even when the auxiliary battery is exhausted, the camera can be used until the main battery is exhausted. In particular, it is possible to know the remaining battery level of the auxiliary battery based on the content displayed on the display means, and when the auxiliary battery is exhausted, it is possible to know the number of images that can be taken without replacing the auxiliary battery. There is.

[Brief description of the drawings]

FIG. 1 is a front view including an internal perspective view of a camera including a power supply device for a camera according to the present invention.

FIG. 2 is a block diagram including the charging circuit shown in FIG.

3 is a circuit diagram showing an embodiment of the booster circuit shown in FIG.

FIG. 4 is a graph showing how the charging energy of the auxiliary battery is transferred to the main battery by the charging circuit shown in FIG.

5A and 5B are plan views of a liquid crystal panel used for explaining display contents of the liquid crystal panel shown in FIG. 2, respectively.

FIG. 6 is a top view including an internal perspective view of a camera including a power supply device for a camera according to the present invention.

7 is a front view including an internal perspective view of the camera shown in FIG.

FIG. 8 is a perspective view showing another embodiment of the power supply device for a camera according to the present invention.

[Explanation of symbols]

 10, 60, 70 ... Power supply device 20 ... Main battery 30 ... Auxiliary battery 32 ... Auxiliary battery housing 40 ... Charging circuit 42 ... Charging control circuit 44 ... Booster circuit 50 ... Liquid crystal panel 50A, 50B, 50C ... Display unit 52 ... Display Control circuit 62 ... Partition plate 64 ... Battery lid 72 ... Power output terminal

Claims (5)

[Claims] 1. A rechargeable main battery for supplying electric power to a power consuming means in a camera, an auxiliary battery accommodating portion to which an auxiliary battery is attachable and detachable, and each time the voltage of the main battery reaches a predetermined lower limit value or A charging unit that operates every time a predetermined amount of power is consumed in the main battery and supplies charging energy from the auxiliary battery to the main battery until the main battery is fully charged; and a remaining battery level of the auxiliary battery is displayed. And a display unit for displaying the number of images that can be taken according to the amount of electricity remaining in the main battery after the auxiliary battery is exhausted. 2. The power supply device for a camera according to claim 1, wherein the main battery is a metal lithium secondary battery. 3. The power supply device for a camera according to claim 1, wherein the auxiliary battery is a manganese-based primary battery. 4. The display means displays the maximum number of shots that can be taken according to the amount of electricity remaining in the main battery immediately after the auxiliary battery is exhausted, and thereafter, the display is displayed each time one shot is taken. 2. The power supply unit for a camera according to claim 1, wherein the number of images that can be taken is counted down and displayed one by one. 5. The power supply device for a camera according to claim 1, wherein the display means detects a voltage of the main battery and displays the number of photographable images based on the detected voltage.