JP2002262168A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video camera that obtains power from a battery of a battery pack, obtains the power for an accessory from the battery when the accessory is used and strengthens the management function of the power supply. SOLUTION: The video camera makes communication with the accessory 30 to obtain information of the power consumption, makes communication with the battery pack 20 to obtain information of the residual capacity of the battery 21. When the residual capacity of the battery 21 is more than the power consumption of the video camera and the accessory 30, a microcomputer 14 permits the operation of the video camera 10 and the accessory 30 in a usual mode. When the residual capacity of the battery 21 is less than the power consumption of the video camera and the accessory 30, the microcomputer 14 activates the video camera 10 or the accessory 30 in a power-saving mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device having an improved power management function.

[0002]

2. Description of the Related Art As a video camera (imaging device), there is an integrated video recording / reproducing device capable of recording and reproducing an imaged video signal. Furthermore, in addition to the recording and playback device,
There is also a video camera in which a non-volatile memory is detachable so that a still image can be stored in the non-volatile memory.

[0003] In addition, such a high-performance video camera is provided with accessories such as a video light, a flash light (so-called strobe), and a video printer so that the functions of the video camera can be utilized. For example,
If a video light or a flash light is used, even a dark subject can capture and record a moving image or a still image. In addition, if a video printer is used, one frame or a still image of a recorded moving image can be printed out on the spot and viewed or distributed.

[0004] These accessories are generally mounted on an accessory shoe provided on a video camera so that the above-described functions can be realized.

[0005]

Generally, the power supply of a video camera is a battery pack containing a rechargeable battery, but accessories generally do not have a built-in power supply. Therefore, when the accessory is used by being attached to the accessory shoe, the operating voltage of the accessory is obtained from the battery pack of the video camera.

Therefore, when the accessory is used, the current consumed from the battery pack is larger than when the accessory is not used, so that the point of time when the remaining battery power is exhausted is earlier, and the photographing time is shortened. I will.

[0007] Therefore, some video cameras are provided with a battery voltage detection circuit, and when the battery voltage drops to a specified value, the supply of voltage to the accessory is limited. For example, in the case of a video light, when the battery voltage drops to a specified value, the current consumption is reduced by reducing the amount of light.

However, even in this case, since the amount of current consumption varies depending on the accessory, appropriate power management may not be performed. For example, when a video light with a large amount of light is used, the current consumption is large, so when the battery voltage drops to a specified value, it is necessary to immediately reduce the light amount of the video light to reduce the current consumption. In the case of a video light with a small amount of light, the current consumption is small, so that even if the battery voltage drops to a specified value, shooting can be continued for a considerable period of time.

The capacity R1 of the battery changes depending on the temperature t as shown in FIG. 7, for example. Furthermore, depending on the model of the video camera, a battery pack having a larger capacity than the standard may be prepared in addition to the battery pack having the standard capacity. Therefore, it is not possible to properly manage the power supply only by detecting a drop in the battery voltage.

The present invention is to solve such a problem.

[0011]

According to the present invention, for example, an imaging device which obtains power from a battery of a battery pack and, when using an accessory, also obtains power of the accessory from the battery of the battery pack. A first communication circuit that communicates with the accessory to obtain information about the power consumption thereof; a second communication circuit that communicates with the battery pack to obtain information about the remaining amount of the battery; In the comparison circuit, the information about the remaining amount of the battery, the power consumption when the device itself is in the normal mode and the information about the power consumption of the sum of the power consumption when the accessory is in the normal mode are compared, If the comparison result indicates that the normal mode itself and the normal mode accessory can operate, the self mode And the accessory is allowed to operate in the normal mode, and when the comparison result indicates that the operation of the normal mode itself and the accessory of the normal mode are impossible, the self or the accessory is allowed to operate. This is an imaging device that is operated in the power save mode. Therefore, the operation mode of the self or the accessory is set according to the remaining amount of the battery and the power consumption of the self and the accessory.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 10 indicates a video camera, reference numeral 20 indicates a battery pack, and reference numeral 30 indicates an accessory.

In the video camera 10, at the time of recording (at the time of image pickup), a subject is picked up by the image pickup unit 11 and a video signal is taken out. It is recorded in a predetermined format on a recording medium such as a memory. At this time,
A part of the recorded video signal is supplied to a monitor (or viewfinder) 13 to monitor the imaged content. At the time of reproduction, a video signal is reproduced and taken out from the recording / reproducing unit 12, and the video signal is supplied to the monitor 13.
Is supplied and displayed.

Further, the video camera 10 has a microcomputer 14 as a system control circuit. The microcomputer 14 controls the imaging unit 11, the recording / reproducing unit 12, and the monitor 13. Further, the microcomputer 14 has, for example, a routine 100 as shown in FIG. 2 as a part of a program executed by its CPU (not shown).

This routine 100 is for controlling the use of the accessory 30, and will be described in detail later. However, when the accessory 30 is not mounted on the video camera 10, it is repeated at a predetermined short cycle. Be executed. Note that, in FIG. 2, the routine 100 only shows portions related to the present invention.

The video camera 10 is provided with a normal mode in which a normal operation is performed and a power save mode in which the power consumption is reduced by turning off the monitor 13, for example. Further, the video camera 10 has an accessory shoe 15 for exclusively mounting any one of the plurality of accessories 30.

Further, the battery pack 20 has a rechargeable battery 21, a temperature sensor 22, and a microcomputer 23 formed as a one-chip IC, and is detachable from the video camera 10. In this case, the temperature sensor 22
Is for measuring the temperature t of the battery 21. The microcomputer 23 holds information on the remaining amount by monitoring the charge and discharge of the battery 21, and also stores the information and the battery 22 measured by the temperature sensor 23.
This is for communicating the information on the temperature t to the video camera 10.

The voltage of the battery 21 of the battery pack 20 is supplied to the microcomputer 23 and the means 11 to 14 as their operating voltages, and the microcomputer 23 is connected to the microcomputer 14 so that the microcomputer 23 has The information is notified to the microcomputer 14. Also, the accessory 30
Is attached to the shoe 15, the voltage of the battery 21 supplied to the video camera 10 is supplied to the accessory 30 through the contact (not shown) of the shoe 15.

The accessory 30 further includes a main body 31
And a microcomputer 32 formed as a one-chip IC. In this case, the accessory 30 includes a video printer, a video light, a flash light, and the like as described above. When the accessory 30 is the video printer 30A as shown in FIG. And a printer mechanism 31A such as a paper feed mechanism.

As shown in FIG. 3B, the accessory 3
When 0 is the video light 30B, the main body 31 is a dimming circuit 31B for controlling the light emission amount of the light source 33B such as a halogen lamp, and as shown in FIG.
If 0 is the flash light 30C, the main unit 31
Is a dimming circuit 31C for controlling the light emission amount of a light source 33C such as a flash discharge tube.

Further, a microcomputer 32 (FIG. 3)
, Reference numerals 32A to 32C) denote accessories 30 provided with the microcomputer 32.
Has identification information for identifying which of the accessories 30A to 30C it is, and information such as whether the accessory 30 has a power consumption mode or a power save mode.

In this case, for example, the video light 30B
Can reduce power consumption by reducing the amount of light emission, and the flashlight 30C can reduce power consumption during charging by reducing the guide number. Therefore, the video light 30B and the flash light 30C can have a power save mode. However, the printer 30A cannot have the power save mode because it is difficult to reduce the power consumption.

Further, the microcomputer 32 notifies the information of the accessory 30 to the video camera 10 and controls the main body 31 in accordance with an instruction from the video camera 10. For this reason, the microcomputer 32 sets the accessory 30 to the accessory shoe 1.
5 is connected to the microcomputer 14.

In such a configuration, the processing of the CPU of the microcomputer 14 starts from step 101 of the routine 100, and then, in step 102,
It is checked whether communication with the microcomputer 32 of the accessory 30 is possible. Then, when communication is not possible, since the accessory 30 is not mounted on the shoe 15, the process proceeds from step 102 to step 103, and this routine 100 ends.

However, in step 102, when communication with the microcomputer 32 is possible, it means that the accessory 30 is mounted on the shoe 15, so the process proceeds from step 102 to step 111, and in this step 111, the microcomputer 32 And the information about the accessory 30 and the main body 31, for example, the accessory 30
A, information indicating which one of the video light 30B and the flash light 30C is used, and information such as power consumption and the presence or absence of a power save mode are received.

Subsequently, in step 112, communication with the microcomputer 23 of the battery pack 20 is performed to receive information on the remaining amount and temperature of the battery 22. Then, in step 113, step 111,
Based on the information obtained by 112, it is determined whether the accessory 30 can be used in the normal mode. This determination is made, for example, as follows.

That is, generally, a standard load (generally,
The remaining amount R of the battery at 20% of the total capacity of the battery is represented by: R = W × T W: electric power supplied to the load [W] T: electric power supply time [h] That is, the remaining amount R indicates how long the constant power W can be supplied to the load over a period of time T.

Also, the battery has a property that the output impedance changes depending on the temperature and load current. When the temperature decreases, the output impedance increases, or even when the load current increases, the output impedance increases. When the output impedance increases, the voltage drop due to the load current increases, and the terminal voltage of the battery decreases by the voltage drop. When the terminal voltage becomes lower than the operable voltage of the load, the load cannot operate.

Accordingly, as shown in FIG. 7, the actual remaining amount R1 of the battery in consideration of the temperature t is as follows: R1 = R0-f (W, t) (2) R0: Standard load, normal temperature The remaining amount at (25 ° C.) f (W, t): is represented by a function of the power W supplied to the load and the temperature t. As a result, the actual remaining usable time T1 of the battery is given by T1 = R1 / W = (R0-f (W, t)) / W (3) from the equations (1) and (2).

The video camera 10 knows the temperature t and the remaining amount R0 of the battery 21, and also knows the total power consumption WALL when the video camera 10 and the accessory 30 are used in the normal mode. Therefore, when the video camera 10 and the accessory 30 are used in the normal mode, the remaining usable time TALL of the battery 21 is used.
From the equation (3), TALL = (R0-f (W, t)) / WALL.

Therefore, in step 113, the remaining usable time TALL of the battery 21 and the accessory 30
Is compared with the time TACC to be used, it can be determined whether or not the accessory 30 can be used in the normal mode. Therefore, the determination in step 113 is that TALL ≧ TACC (4) It depends on whether or not.

When the expression (4) is satisfied, the video camera 10 and the accessory 30 can be driven in the normal mode for at least the period TACC, so that the process proceeds from the step 113 to the step 121. 32,
Commands and data permitting the accessory 30 to operate in the normal mode are transmitted, and then the process returns to step 102.

In the accessory 30, when the microcomputer 32 receives the command and data in step 121, the microcomputer 32 changes the parameters of each unit so that the main unit 31 operates in the normal mode according to the received command and data. Set. Therefore, in this case, the video camera 10 and the accessory 30
Will operate in normal mode.

However, if the expression (4) is not satisfied in step 113, it means that at least one of the video camera 10 and the accessory 30 cannot be driven in the normal mode.
And in this step 114, step 111
It is determined whether or not the accessory 30 has the power save mode from the communication result.

When the accessory 30 has the power save mode, the process proceeds from step 114 to step 115, where it is determined whether the accessory 30 can be driven in the power save mode for the period TACC.

In this case, if the video camera 10 is used in the normal mode and the total power consumption when the accessory 30 is used in the power save mode is W10, the remaining usable time T10 of the battery 21 at this time is From equation (3), T10 = (R0-f (W, t)) / W10.

Therefore, in step 115, it is determined whether the accessory 30 can be used in the normal mode by comparing the remaining usable time T10 of the battery 21 with the time TACC when the accessory 30 is to be used. Therefore, the determination in step 115 is made based on whether or not T10 ≧ TACC (5) holds.

When the expression (5) is satisfied, the video camera 10 can be driven in the normal mode for at least the period TALL, and the accessory 30 can be driven in the power save mode. Therefore, the process proceeds from step 115 to step 122. , This step 122
In the microcomputer 32, the accessory 3
A command and data that allow 0 to operate in the power save mode are transmitted, after which the process returns to step 102.

In the accessory 30, when the microcomputer 32 receives the command and the data in step 122, the microcomputer 32 controls the parameters of the respective components so that the main body 31 operates in the power save mode in accordance with the received command and the data. Set. Therefore, in this case, the video camera 10 operates in the normal mode, and the accessory 30 operates in the power save mode.

However, if the expression (5) is not satisfied in step 115, the accessory 30 cannot be driven even in the power save mode.
15 to step 123, in which the accessory 32 is
Is transmitted, and a message indicating that the accessory 30 cannot be used is displayed on the monitor 13 because the remaining amount of the battery 21 is low. Then, the process returns to step 102. Therefore, in this case,
Only the video camera 10 can be used.

Further, when the accessory 30 does not have the power save mode in step 114, the process proceeds from step 114 to step 116, in which the video camera 10 is operated for the period TACC.
Is determined in the power save mode.

In this case, if the video camera 10 is used in the power save mode and the total power consumption when the accessory 30 is used normally is W30, the remaining usable time T30 of the battery 21 at this time is represented by ( From equation (3), T30 = (R0-f (W, t)) / W30.

Therefore, in step 116, it is determined whether the accessory 30 can be used in the normal mode by comparing the remaining usable time T30 of the battery 21 with the time TACC when the accessory 30 is to be used. Therefore, the determination in step 116 is made based on whether or not T30 ≧ TACC (6) holds.

When equation (6) holds, the video camera 10 can be driven in the power save mode and the accessory 30 can be driven in the normal mode for at least the period TALL.
From 16, the process proceeds to step 124, in which the video camera 10 is changed to the power save mode, and a command and data for permitting the accessory 30 to operate in the normal mode are transmitted to the microcomputer 32. , Processing is step 1
Return to 02.

In the accessory 30, when the microcomputer 32 receives the command and the data in step 124, the microcomputer 32 changes the parameters of the respective parts so that the main body 31 operates in the normal mode according to the received command and the data. Set. Therefore, in this case, the video camera 10 operates in the power save mode, and the accessory 30 operates in the normal mode.

However, if the equation (6) is not established in step 116, the video camera 10 cannot be driven even in the power save mode, so that the processing proceeds from step 116 to step 123, and this step 123
In the microcomputer 32, the accessory 3
A command to prohibit operation of the accessory 30 is transmitted, and the monitor 13 indicates that the accessory 30 cannot be used because the remaining amount of the battery 21 is low, and then the process returns to step 102. Therefore, in this case, only the video camera 10 can be used.

Therefore, when the accessory 30 is the printer 30A, the routine 100 is as shown in FIG. 4. When the accessory 30 is the video light 30B or the flash light 30C, the routine 100 is executed. 100 is as shown in FIG. 5 or FIG.

As described above, according to the video camera 10 and the accessory 30 described above, the operation is performed in the normal mode or the power save mode according to the power consumption of the accessory 30 and the remaining amount of the battery 21. Battery 21
Can be used efficiently. In addition, it is possible to maximize the usable time of the battery 21 when using the accessory 30.

[List of abbreviations used in this specification] CPU: Central Processing Unit IC: Integrated Circuit

[0050]

According to the present invention, the battery can be efficiently used without running out of the battery during use of the accessory. In addition, this can maximize the usable time of the battery when using the accessory.

[Brief description of the drawings]

FIG. 1 is a system diagram illustrating one embodiment of the present invention.

FIG. 2 is a flowchart illustrating one embodiment of the present invention.

FIG. 3 is a system diagram for explaining the present invention.

FIG. 4 is a flowchart for explaining the present invention.

FIG. 5 is a flowchart for explaining the present invention.

FIG. 6 is a flowchart for explaining the present invention.

FIG. 7 is a characteristic diagram for explaining the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Video camera, 11 ... Imaging part, 12 ... Recording / reproducing part, 13 ... Monitor, 14 ... Microcomputer, 15
... Accessory shoe, 20 ... Battery pack, 21 ... Rechargeable battery, 22 ... Temperature sensor, 23 ... Microcomputer, 30 ... Accessories, 31 ... Main body, 32 ... Microcomputer

Claims (3)

[Claims] 1. An imaging device which receives power from a battery of a battery pack and uses an accessory when the accessory is used. The imaging device communicates with the accessory and consumes power when the accessory is used from the battery of the battery pack. A first communication circuit that obtains information about power; a second communication circuit that communicates with the battery pack to obtain information about the remaining amount of the battery; and a comparison circuit. Information about the remaining power of the normal mode and the information about the power consumption of the sum of the power consumption when the device itself is in the normal mode and the power consumption when the accessory is in the normal mode. When it indicates that the accessory in the normal mode can operate, the device itself and the accessory operate in the normal mode. When the comparison result indicates that the operation of the normal mode itself and the accessory of the normal mode are not possible, the self or the accessory is operated in the power save mode. Imaging device. 2. The image pickup apparatus according to claim 1, wherein when the comparison result indicates that the operation of the normal mode itself and the operation of the accessory in the normal mode are impossible, the comparison circuit includes: The information on the remaining amount of the battery is compared with the information on the power consumption when the device itself is in the normal mode and the power consumption when the accessory is in the power save mode. When the mode itself and the accessory in the power save mode indicate that the operation is possible, the device itself operates in the normal mode, and the accessory is allowed to operate in the power save mode. Indicates that the operation of the normal mode itself and the accessory of the power save mode are not possible. An imaging device that prohibits the operation of the accessory when the operation is performed. 3. The imaging device according to claim 1, wherein when the comparison result indicates that the operation of the normal mode itself and the accessory of the normal mode are not possible, The information on the remaining amount of the battery is compared with the information on the power consumption when the device itself is in the power save mode and the sum of the power consumption when the accessory is in the normal mode. When the operation in the save mode and the accessory in the normal mode indicate that the accessory can be operated, the device itself operates in the power save mode, and the accessory is allowed to operate in the normal mode. Indicates that the operation of the normal mode itself and the accessory of the power save mode are not possible. An image pickup apparatus that prohibits the operation of the accessory when the operation is performed.