U.S. patent application number 10/808524 was filed with the patent office on 2005-03-24 for power system and camera.
This patent application is currently assigned to NIKON CORPORATION. Invention is credited to Nomoto, Tetsushi, Ogawa, Hidehiro.
Application Number | 20050062878 10/808524 |
Document ID | / |
Family ID | 34315590 |
Filed Date | 2005-03-24 |
United States Patent
Application |
20050062878 |
Kind Code |
A1 |
Ogawa, Hidehiro ; et
al. |
March 24, 2005 |
Power system and camera
Abstract
A camera includes: a battery unit on which a battery is mounted,
that can be detachably loaded into the camera and supplies power to
the camera; and a function unit that executes camera functions,
wherein: as a function of the camera is executed, the function unit
transmits information related to the executed function to the
battery pack; and the battery unit has a storage unit in which the
information related to the camera function is stored.
Inventors: |
Ogawa, Hidehiro;
(Fanabashi-shi, JP) ; Nomoto, Tetsushi;
(Hodagaya-ku, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
NIKON CORPORATION
Tokyo
JP
NIKON TECHNOLOGIES INC.
Tokyo
JP
|
Family ID: |
34315590 |
Appl. No.: |
10/808524 |
Filed: |
March 25, 2004 |
Current U.S.
Class: |
348/372 ;
348/E5.042 |
Current CPC
Class: |
H04N 5/23241 20130101;
H02J 7/0047 20130101; H04N 5/232941 20180801 |
Class at
Publication: |
348/372 |
International
Class: |
H04N 005/225 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 26, 2003 |
JP |
2003-086455 |
May 7, 2003 |
JP |
2003-128867 |
Claims
What is claimed is;
1. A power system comprising: a battery unit that includes a
battery; and an apparatus main body that operates on power supplied
from the battery in the battery unit mounted thereat, the battery
unit and the apparatus main body being engaged in information
exchange, wherein: a work volume value indicating a volume of work
that the apparatus main body has been engaged in is transmitted
from the apparatus main body to the battery unit over a
predetermined cycle; the battery unit calculates a cumulative work
volume value of the work volume value at the apparatus main body
and stores the cumulative work volume value therein, and the
battery unit also detects a consumed battery capacity value
indicating an extent to which a battery power has been consumed at
the apparatus main body; the cumulative work volume value, the
consumed battery capacity value and a charged battery capacity
value are transmitted from the battery unit to the apparatus main
body over the predetermined cycle; and the apparatus main body
displays a battery use rate indicating an extent to which the
battery has been used based upon the consumed battery capacity
value and the charged battery capacity value, and also displays the
cumulative work volume value at the apparatus main body.
2. A power system according to claim 1, wherein: different
operating modes of the apparatus main body are classified in
correspondence to varying levels of power consumption; work volume
values each corresponding to one of the operating modes are
transmitted from the apparatus main body to the battery unit; the
battery unit calculates and stores therein cumulative work volume
values corresponding to the individual operating modes of the
apparatus main body and transmits the cumulative work volume values
corresponding to the individual operating modes to the apparatus
main body; and the apparatus main body displays the battery use
rate and the cumulative work volume values corresponding to the
individual operating modes of the apparatus main body.
3. A power system according to claim 1, wherein: the battery unit
allows the battery to be charged with a charge apparatus; the
battery unit and the charge apparatus exchange information with
each other; and the cumulative work volume value stored in the
battery unit is reset to 0 when the battery has been charged by the
charge apparatus.
4. A power system according to claim 2, wherein: the battery unit
allows the battery to be charged with a charge apparatus; the
battery unit and the charge apparatus exchange information with
each other; and the cumulative work volume value stored in the
battery unit is reset to 0 when the battery has been charged by the
charge apparatus.
5. A power system according to claim 1, wherein: the battery unit
allows the battery to be charged with a charge apparatus; the
battery unit and the charge apparatus exchange information with
each other; the battery unit detects the charged battery capacity
value and transmits the detected charged battery capacity value to
the charge apparatus; the charge apparatus makes a decision based
upon the charged capacity value transmitted from the battery unit
as to whether or not the battery is in a fully charged state and
ends a charge of the battery once the battery is judged to be in
the fully charged state; and the battery unit resets the consumed
battery capacity value stored in memory at the battery unit to 0
when the charge of the battery ends.
6. A power system according to claim 1, wherein: the apparatus main
body is a camera; and the work volume value is a number of frames
of images photographed in the camera.
7. A power system according to claim 1, wherein: the apparatus main
body is a camera; and the work volume value is a length of time
over which the camera has been engaged in use.
8. A camera comprising: a battery unit on which a battery is
mounted, that can be detachably loaded into the camera and supplies
power to the camera; and a function unit that executes camera
functions, wherein: as a function of the camera is executed, the
function unit transmits information related to the executed
function to the battery pack; and the battery unit has a storage
unit in which the information related to the camera function is
stored.
9. A camera according to claim 8, wherein: the function unit
accumulates information related to the camera functions and
transmits the accumulated information related to the camera
functions to the battery unit; and the storage unit stores therein
the accumulated information related to the camera functions having
been transmitted.
10. A camera according to claim 8, wherein: the storage unit
accumulates the information related to the camera function
transmitted thereto and stores therein the accumulated
information.
11. A camera having loaded therein a battery unit that includes a
battery and a first storage unit, which operates on power supplied
from the battery unit, comprising: a function unit that executes a
plurality of functions of the camera; a control unit; and a second
storage unit, wherein: the second storage unit stores therein
cumulative information indicating a value that accumulate as a
function is engaged; and the control unit transmits to and stores
into the first storage unit the cumulative information in the
second storage unit as a first function is engaged, and then resets
the cumulative information at the second storage unit; the control
unit reads the cumulative information stored in the first storage
unit of the battery unit from the battery unit as a second function
is engaged; the control unit obtains a sum of the cumulative
information having been read and cumulative information stored in
the second storage unit after resetting; and the control unit uses
the sum of the cumulative information thus obtained as new
cumulative information to be transmitted to the battery unit.
12. A camera according to claim 11, wherein: the control unit reads
the cumulative information from the first storage unit as a
function to be engaged first is engaged and transmits the
cumulative information to the first storage unit as a function to
be engaged last is engaged.
13. A camera according to claim 11, wherein: a plurality of
functions include at least one of an image photographing function,
a monitor display function, a light emitting illumination function,
an AF function and a zoom function; and the cumulative information
includes at least one of a number of images that are photographed,
an accumulated time length of monitor display device ON time, a
number of times light has been emitted for illumination, an
accumulated length of AF operation time and an accumulated length
of zoom operation time.
14. A camera that operates on power supplied from a battery unit
loaded therein having a chargeable secondary battery, a measurement
unit that measures remaining battery power value in the secondary
battery and a first storage unit in which the remaining battery
power value is stored, comprising: a function unit that executes a
plurality of functions of the camera; a control unit; a second
storage unit; and a display unit, wherein: the second storage unit
stores therein cumulative information indicating values that
accumulate as the functions are engaged; the control unit transmits
to and stores into the first storage unit the cumulative
information as a first function is engaged, and then resets the
cumulative information at the second storage unit; the control unit
reads the remaining battery power value and the cumulative
information from the battery unit as a second function is engaged;
the control unit reads the remaining battery power value as each of
the plurality of functions is engaged, displays the remaining
battery power value thus read at the display unit, and obtains a
sum of the cumulative information having been read and cumulative
information stored in the second storage unit; the control unit
uses the sum of the cumulative information thus obtained as new
cumulative information to be transmitted to the battery unit.
15. A camera system comprising: a battery unit having a chargeable
secondary battery, a measurement unit that measures remaining
battery power value in the secondary battery and a first storage
unit in which the remaining battery power value is stored; a camera
that operates on power supplied from the battery unit loaded
therein; and a charge apparatus that charges the secondary battery
of the battery unit, wherein: the camera includes a function unit
that executes a plurality of functions of the camera, a control
unit, a second storage unit, and a display unit; the second storage
unit stores therein cumulative information indicating values that
accumulate as the functions are engaged; the control unit reads the
remaining battery power value as each of the functions is engaged
and displays the remaining battery power value thus read at the
display unit; the control unit reads the cumulative information
stored in the first storage unit as one of the functions is
engaged; the control unit obtains a sum of the cumulative
information having been read and the cumulative information stored
in the second storage unit; the control unit transmits the sum to
the battery unit for storage and also resets the cumulative
information at the second storage unit as another function is
engaged; and the charge apparatus resets the cumulative information
stored in the first storage unit when the secondary battery in the
battery unit has been charged.
16. An electronic apparatus system comprising: a battery unit
having a chargeable secondary battery, a measurement unit that
measures remaining battery power value in the secondary battery and
a first storage unit in which the remaining battery power value is
stored; an electronic apparatus that operates on power supplied
from the battery unit loaded therein; and a charge apparatus that
charges the secondary battery of the battery unit, wherein: the
electronic apparatus includes a function unit that executes a
plurality of functions of the electronic apparatus, a control unit,
a second storage unit, and a display unit; the second storage unit
stores therein information that is altered as the functions are
engaged; the control unit reads the information stored in the first
storage unit as one of the functions is engaged; the control unit
generates the information with new content based upon the
information having been read and the information stored in the
second storage unit; the control unit transmits the information
with new content to the battery unit for storage and also resets
the information in the second storage unit as another function is
engaged; and the charge apparatus resets the information stored in
the first storage unit when the secondary battery in the battery
unit has become charged.
Description
INCORPORATION BY REFERENCE
[0001] The disclosures of the following priority applications are
herein incorporated by reference:
[0002] Japanese Patent Application No. 2003-086455 filed Mar. 26,
2003
[0003] Japanese Patent Application No. 2003-128867 filed May 7,
2003
BACKGROUND OF THE INVENTION
[0004] 1. Field of Invention
[0005] The present invention relates to a power system used in an
apparatus such as a camera that operates on batteries and also
relates to a camera.
[0006] 2. Description of the Related Art
[0007] There are power systems used in cameras in the related art
that indicate the number of photographs that can be taken
calculated based upon the remaining battery capacity and the power
requirement for taking a single photograph. Such power systems
include those disclosed in Japanese Laid Open Patent Publication
No. H 10-341536 and Japanese Laid Open Patent Publication No.
2001-154250.
[0008] However, a camera power system in the related art such as
those described above cannot calculate the exact remaining number
of photographs that can be taken on the remaining power when it is
adopted in, for instance, a digital camera, in which the battery
power required per frame greatly varies depending upon the length
of time over which the shutter release button is held halfway down,
whether or not a strobe is used, the size of the image recorded,
whether or not the image is displayed at the monitor and the
like.
[0009] In addition, cameras come equipped with various functions
today. Digital cameras, in particular, offer many functions.
However, with a digital camera in the related art, a history of
consumed battery capacity that has resulted in the presently
remaining battery power level, i.e., which functions of the digital
camera have been engaged to lead to the presently remaining battery
power level, cannot be ascertained. If the history of the consumed
battery capacity in the digital camera indicating specific
functions that have been engaged can be ascertained, it will be
possible to generate useful information based upon the consumed
battery capacity history.
SUMMARY OF THE INVENTION
[0010] The present invention provides a power system capable of
ascertaining with ease the remaining work volume and the remaining
work time available in an apparatus which operates on battery
power.
[0011] The present invention also provides a camera with which it
is possible to ascertain how the battery power has been
consumed.
[0012] According to the 1st aspect of the invention, a power system
comprises: a battery unit that includes a battery; and an apparatus
main body that operates on power supplied from the battery in the
battery unit mounted thereat, the battery unit and the apparatus
main body being engaged in information exchange, wherein: a work
volume value indicating a volume of work that the apparatus main
body has been engaged in is transmitted from the apparatus main
body to the battery unit over a predetermined cycle; the battery
unit calculates a cumulative work volume value of the work volume
value at the apparatus main body and stores the cumulative work
volume value therein, and the battery unit also detects a consumed
battery capacity value indicating an extent to which a battery
power has been consumed at the apparatus main body; the cumulative
work volume value, the consumed battery capacity value and a
charged battery capacity value are transmitted from the battery
unit to the apparatus main body over the predetermined cycle; and
the apparatus main body displays a battery use rate indicating an
extent to which the battery has been used based upon the consumed
battery capacity value and the charged battery capacity value, and
also displays the cumulative work volume value at the apparatus
main body.
[0013] According to the 2nd aspect of the invention, in the power
system according to the 1st aspect, it is preferred that: different
operating modes of the apparatus main body are classified in
correspondence to varying levels of power consumption; work volume
values each corresponding to one of the operating modes are
transmitted from the apparatus main body to the battery unit; the
battery unit calculates and stores therein cumulative work volume
values corresponding to the individual operating modes of the
apparatus main body and transmits the cumulative work volume values
corresponding to the individual operating modes to the apparatus
main body; and the apparatus main body displays the battery use
rate and the cumulative work volume values corresponding to the
individual operating modes of the apparatus main body.
[0014] According to the 3rd aspect of the invention, in the power
system according to the 1st aspect, it is preferred that: the
battery unit allows the battery to be charged with a charge
apparatus; the battery unit and the charge apparatus exchange
information with each other; and the cumulative work volume value
stored in the battery unit is reset to 0 when the battery has been
charged by the charge apparatus.
[0015] According to the 4th aspect of the invention, in the power
system according to the 2nd aspect, it is preferred that: the
battery unit allows the battery to be charged with a charge
apparatus; the battery unit and the charge apparatus exchange
information with each other; and the cumulative work volume value
stored in the battery unit is reset to 0 when the battery has been
charged by the charge apparatus.
[0016] According to the 5th aspect of the invention, in the power
system according to the 1st aspect, it is preferred that: the
battery unit allows the battery to be charged with a charge
apparatus; the battery unit and the charge apparatus exchange
information with each other; the battery unit detects the charged
battery capacity value and transmits the detected charged battery
capacity value to the charge apparatus; the charge apparatus makes
a decision based upon the charged capacity value transmitted from
the battery unit as to whether or not the battery is in a fully
charged state and ends a charge of the battery once the battery is
judged to be in the fully charged state; and the battery unit
resets the consumed battery capacity value stored in memory at the
battery unit to 0 when the charge of the battery ends.
[0017] According to the 6th aspect of the invention, in the power
system according to the 1st aspect, it is preferred that: the
apparatus main body is a camera; and the work volume value is a
number of frames of images photographed in the camera.
[0018] According to the 7th aspect of the invention, in the power
system according to the 1st aspect, it is preferred that: the
apparatus main body is a camera; and the work volume value is a
length of time over which the camera has been engaged in use.
[0019] According to the 8th aspect of the invention, a camera
comprises: a battery unit on which a battery is mounted, that can
be detachably loaded into the camera and supplies power to the
camera; and a function unit that executes camera functions,
wherein: as a function of the camera is executed, the function unit
transmits information related to the executed function to the
battery pack; and the battery unit has a storage unit in which the
information related to the camera function is stored.
[0020] According to the 9th aspect of the invention, in the camera
according to the 8th aspect, it is preferred that: the function
unit accumulates information related to the camera functions and
transmits the accumulated information related to the camera
functions to the battery unit; and the storage unit stores therein
the accumulated information related to the camera functions having
been transmitted.
[0021] According to the 10th aspect of the invention, in the camera
according to the 8th aspect, it is preferred that: the storage unit
accumulates the information related to the camera function
transmitted thereto and stores therein the accumulated
information.
[0022] According to the 11th aspect of the invention, a camera
having loaded therein a battery unit that includes a battery and a
first storage unit, which operates on power supplied from the
battery unit, comprises: a function unit that executes a plurality
of functions of the camera; a control unit; and a second storage
unit, wherein: the second storage unit stores therein cumulative
information indicating a value that accumulate as a function is
engaged; and the control unit transmits to and stores into the
first storage unit the cumulative information in the second storage
unit as a first function is engaged, and then resets the cumulative
information at the second storage unit; the control unit reads the
cumulative information stored in the first storage unit of the
battery unit from the battery unit as a second function is engaged;
the control unit obtains a sum of the cumulative information having
been read and cumulative information stored in the second storage
unit after resetting; and the control unit uses the sum of the
cumulative information thus obtained as new cumulative information
to be transmitted to the battery unit.
[0023] According to the 12th aspect of the invention, in the camera
according to the 11th aspect, it is preferred that: the control
unit reads the cumulative information from the first storage unit
as a function to be engaged first is engaged and transmits the
cumulative information to the first storage unit as a function to
be engaged last is engaged.
[0024] According to the 13th aspect of the invention, in the camera
according to the 11th aspect, it is preferred that: a plurality of
functions include at least one of an image photographing function,
a monitor display function, a light emitting illumination function,
an AF function and a zoom function; and the cumulative information
includes at least one of a number of images that are photographed,
an accumulated time length of monitor display device ON time, a
number of times light has been emitted for illumination, an
accumulated length of AF operation time and an accumulated length
of zoom operation time.
[0025] According to the 14th aspect of the invention, a camera that
operates on power supplied from a battery unit loaded therein
having a chargeable secondary battery, a measurement unit that
measures remaining battery power value in the secondary battery and
a first storage unit in which the remaining battery power value is
stored, comprises: a function unit that executes a plurality of
functions of the camera; a control unit; a second storage unit; and
a display unit, wherein: the second storage unit stores therein
cumulative information indicating values that accumulate as the
functions are engaged; the control unit transmits to and stores
into the first storage unit the cumulative information as a first
function is engaged, and then resets the cumulative information at
the second storage unit; the control unit reads the remaining
battery power value and the cumulative information from the battery
unit as a second function is engaged; the control unit reads the
remaining battery power value as each of the plurality of functions
is engaged, displays the remaining battery power value thus read at
the display unit, and obtains a sum of the cumulative information
having been read and cumulative information stored in the second
storage unit; the control unit uses the sum of the cumulative
information thus obtained as new cumulative information to be
transmitted to the battery unit.
[0026] According to the 15th aspect of the invention, a camera
system comprises: a battery unit having a chargeable secondary
battery, a measurement unit that measures remaining battery power
value in the secondary battery and a first storage unit in which
the remaining battery power value is stored; a camera that operates
on power supplied from the battery unit loaded therein; and a
charge apparatus that charges the secondary battery of the battery
unit, wherein: the camera includes a function unit that executes a
plurality of functions of the camera, a control unit, a second
storage unit, and a display unit; the second storage unit stores
therein cumulative information indicating values that accumulate as
the functions are engaged; the control unit reads the remaining
battery power value as each of the functions is engaged and
displays the remaining battery power value thus read at the display
unit; the control unit reads the cumulative information stored in
the first storage unit as one of the functions is engaged; the
control unit obtains a sum of the cumulative information having
been read and the cumulative information stored in the second
storage unit; the control unit transmits the sum to the battery
unit for storage and also resets the cumulative information at the
second storage unit as another function is engaged; and the charge
apparatus resets the cumulative information stored in the first
storage unit when the secondary battery in the battery unit has
been charged.
[0027] According to the 16th aspect of the invention, an electronic
apparatus system comprises: a battery unit having a chargeable
secondary battery, a measurement unit that measures remaining
battery power value in the secondary battery and a first storage
unit in which the remaining battery power value is stored; an
electronic apparatus that operates on power supplied from the
battery unit loaded therein; and a charge apparatus that charges
the secondary battery of the battery unit, wherein: the electronic
apparatus includes a function unit that executes a plurality of
functions of the electronic apparatus, a control unit, a second
storage unit, and a display unit; the second storage unit stores
therein information that is altered as the functions are engaged;
the control unit reads the information stored in the first storage
unit as one of the functions is engaged; the control unit generates
the information with new content based upon the information having
been read and the information stored in the second storage unit;
the control unit transmits the information with new content to the
battery unit for storage and also resets the information in the
second storage unit as another function is engaged; and the charge
apparatus resets the information stored in the first storage unit
when the secondary battery in the battery unit has become
charged.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1 shows the structure of the electronic still camera
achieved in a first embodiment;
[0029] FIGS. 2A and 2B show the timing with which the camera main
body and the secondary battery unit communicate with each
other;
[0030] FIG. 3 presents an example of a battery information
display;
[0031] FIGS. 4A and 4B present flowcharts of the battery
information display processing executed at the camera main body and
the secondary battery unit;
[0032] FIG. 5 shows the structure adopted in the charger used to
charge the secondary battery unit;
[0033] FIG. 6 presents flowcharts of the charge processing executed
at the charger and the secondary battery unit;
[0034] FIGS. 7A and 7B schematically illustrate the system
configuration adopted in a second embodiment;
[0035] FIG. 8 shows the structure of the DSC;
[0036] FIG. 9 shows the structure of the charge unit;
[0037] FIG. 10 presents the first half of the flowchart of the
operational procedure at the DSC;
[0038] FIG. 11 presents the second half of the flowchart of the
operational procedure at the DSC;
[0039] FIG. 12 presents a flowchart of the photographing mode
startup processing;
[0040] FIG. 13 presents a flowchart of the reproduction mode
startup processing;
[0041] FIG. 14 presents a flowchart of the processing executed on
information related to the DSC; and
[0042] FIG. 15 presents an example of a display which may be
brought up at the monitor display unit to indicate the numbers of
pictures that may be taken in correspondence to various
photographing conditions.
DESCRIPTION OF PREFERRED EMBODIMENTS
First Embodiment
[0043] The first embodiment in which the present invention is
adopted in an electronic still camera is now explained. It is to be
noted that the present invention may be adopted in all types of
devices and apparatuses that operate on secondary batteries
(rechargeable batteries).
[0044] FIG. 1 shows the structure of the electronic still camera
achieved in the embodiment. A secondary battery unit 30 is mounted
at a camera main body 10. The secondary battery unit 30 is a
detachable unit that can be freely attached to or detached from the
camera main body 10. The camera main body 10 includes a
photographic lens 11, an aperture 12, a shutter 13, an
image-capturing element 14, a CDS.cndot.A/D conversion unit 15 that
converts the output from the image-capturing element 14 to digital
values through correlated double sampling, an image processing unit
16, a display control unit 17 that implements control to display a
captured image, an image display LCD 18, a timing generator that
controls the timing with which the image-capturing element 14 and
the CDS.cndot.A/D conversion unit 15 are engaged in operation, a
controller 20 that controls the devices and circuits in the
image-capturing system, an image memory 21 in which image data are
recorded, a motor driver 22, an AF motor 23 that drives a focusing
lens at the photographic lens 11, an aperture control actuator 24,
a shutter control actuator 25, a camera controller 26 that controls
the devices and circuits in the photographic system, an operation
input unit 27 through which operations such as the shutter release
operation are input, a display output unit 28 utilized to display
exposure information and the like, a DC/DC converter 29 that
generates a voltage needed at the camera and the like.
[0045] The secondary battery unit 30 includes a battery controller
31 that monitors the consumed battery capacity, the charged battery
capacity and the like, a memory 32 in which a cumulative value
indicating a camera use status, the consumed battery capacity, the
charged battery capacity and the like are stored, a capacity
calculation element 33 that measures the consumed battery capacity
and the charged battery capacity, battery cells 34, a resistor 35
that detects the consumption current and the charge current at the
battery and the like.
[0046] As the secondary battery unit 30 is mounted at the camera
main body 10, the battery cells 34 of the secondary battery unit 30
become connected with the DC/DC converter 29 at the camera main
body 10 via the resistor 35 and also, the battery controller 31 and
the camera controller 26 become connected with each other via a
communication line.
[0047] In the case of an electronic still camera, the term "camera
use statuses" refers to the statuses of camera operations that need
power from the battery unit 30, such as the number of shutter
releases, the length of time over which the power has been in an ON
state (the length of time over which the camera has been in use),
the length of time over which the photographic lens has been
engaged in focusing operation and the length of time over which
images have been displayed. At least one of such camera use
statuses, e.g., the number of shutter releases, is provided from
the camera controller 26 to the battery controller 31 in a
predetermined cycle. At the battery controller 31, a cumulative
value calculated by using the use statuses having been received is
stored in the memory 32 and the calculated value indicating the use
status is transmitted to the camera controller 26.
[0048] At the secondary battery unit 30, the capacity calculation
element 33 detects the consumption current and calculates the
battery capacity being consumed. As the current, i.e., the
consumption current being used at the camera main body 10, which
flows from the battery cells 34 to the DC/DC converter 29 of the
camera main body 10, passes through the resistor 35, a voltage
(=consumption current.times.resistance value) is generated at the
two ends of the resistor 35 in proportion to the consumption
current. Since the capacity of a battery is normally indicated in
units of (mAH) and is defined as the length of time over which the
battery is capable of continuously supplying a specific current,
the consumption current can be detected by measuring the voltage
level at the two ends of the resistor 35, and the battery capacity
being consumed at the camera main body 10 can be ascertained
through a time integration of the consumption current. The consumed
battery capacity detected by the capacity calculation element 33 is
stored into the memory 32 via the battery controller 31.
[0049] The camera controller 26 at the camera main body 10 and the
battery controller 31 at the secondary battery unit 30 engage in
data communication over a predetermined cycle, as shown in FIG. 2.
The use status of the camera main body 10 explained earlier is
transmitted from the camera main body 10 to the secondary battery
unit 30 over a specific cycle, as shown in FIG. 2(a). The use
status transmitted from the camera main body 10 to the secondary
battery unit 30 over the specific cycle through the data
communication is a value corresponding to the time between the
preceding use status transmission and the present use status
transmission. For instance, if the number of shutter releases is
transmitted as the use status, the use status indicates the number
of shutter releases having been performed between the preceding
transmission and the present transmission.
[0050] The battery controller 31 adds the use status transmitted
from the camera main body 10 to the secondary battery unit 30 to
the use status cumulative value stored in the memory 32 which was
calculated at the time of previous use status reception. If the
number of shutter releases has been received as the use status, for
instance, the most recently received number of shutter releases is
added to the shutter release cumulative value stored in the memory
32 calculated at the time of the previous reception.
[0051] After information such as the use status is transmitted from
the camera main body 10 to the secondary battery unit 30, the
secondary battery unit 30 executes processing such as the
calculation of the cumulative value indicating the cameras use
status and the calculation of the consumed battery capacity, and
once the processing is completed, the secondary battery unit 30
transmits information such as the use status cumulative value to
the camera main body 10. The information transmitted from the
secondary battery unit 30 to the camera main body 10 includes the
use cumulative value stored in the memory 32, the consumed capacity
calculated at the secondary battery unit 30 and the charged
capacity of the secondary battery unit 30.
[0052] The term "charged capacity" used with respect to the
secondary battery unit 30 refers to the full charged capacity of
the secondary battery unit 30, which may be the rated capacity of
the battery cells 34 or may be indicated by a value obtained by
lowering the rated capacity in correspondence to the extent to
which the charge capacity of the battery cells becomes reduced due
to battery degradation occurring over time.
[0053] For instance, if a value "2" indicating the number of
shutter releases is transmitted from the camera main body 10 to the
secondary battery unit 30 during a communication 1, a value "3" is
transmitted during a communication 2, a value "0" is transmitted
during a communication 3 and a value "2" is transmitted during
communication 4 in FIG. 2, a shutter release cumulative value of 2
is transmitted from the secondary battery unit 30 to the camera
main body 10 during a communication 1', a shutter release cumulated
value of 5 is transmitted during a communication 2', a shutter
release cumulative value 5 is transmitted during a communication 3'
and a shutter release cumulative value of 7 is transmitted during a
communication 4'.
[0054] The cycle over which the camera main body 10 and the
secondary battery unit 30 engage in communication with each other
on a regular basis is normally several seconds. However, some use
statuses may be sustained over longer periods of time than the
communication cycle. For instance, the power ON state (length of
time over which the camera remains in use) may last over 10 seconds
up to several tens of seconds. If a use status that is likely to be
sustained over a much longer time than the regular communication
cycle is transmitted through the regular communication, a
cumulative error may occur. For this reason, a use status such as
the power ON time likely to last longer than the regular
communication cycle may be transmitted over a longer interval than
the regular communication cycle, or it may be transmitted when the
power is turned off.
[0055] As a battery information display request as issued through
the operation input unit 27, the camera controller 26 at the camera
main body 10 displays information with regard to the secondary
battery unit 30, such as that shown in FIG. 3, based upon the use
status cumulative value, the consumed battery capacity and the full
charged capacity received from the secondary battery unit 30. A
battery use quantity is displayed as the ratio (%) of the consumed
capacity to the full charged capacity in a bar graph. In the
example presented in FIG. 3, the ratio of the consumed capacity to
the full charged capacity is indicated as the use quantity in a bar
graph, together with a numerical value "35%".
[0056] The shutter release cumulative value "253 frames" and the
cumulative power ON time, i.e., the use time, "35 min 40 sec"
corresponding to 35% to which extent the battery has been used
after the fully charged secondary battery unit 30 was mounted at
the camera main body 10, are indicated as use statuses.
[0057] Since the battery information in FIG. 3 indicates the number
of times the shutter has been released in the camera, "253 frames",
and the use time "35 min 40 sec", corresponding to a battery use
quantity "35%" to which extent the fully charged battery has become
consumed at the present time point, the user can correlate the
actual performance, i.e., 253 frames of photographed images and
over 35 minutes of use, to the battery use quantity of 35%. Then,
based upon the camera use records (work records) corresponding to
the battery use quantity representing the extent to which the fully
charged battery has become consumed to the present level, the user
can easily estimate the number of frames of images that can be
photographed (the work volume) and the length of time over which
the camera can be engaged in use on the remaining 65% of the
battery power. In other words, by adopting the embodiment, it
becomes possible to judge with ease how many more frames of images
can be photographed and how much longer the camera can be used in
operation.
[0058] FIG. 4 presents flowcharts of the processing executed at the
camera main body 10 and the secondary battery unit 30 over the
predetermined cycle. In reference to these flowcharts, the
operations executed at the camera main body 10 and the secondary
battery unit 30 in the embodiment are explained.
[0059] The camera controller 26 at the camera main body 10 executes
the processing in FIG. 4(a) over the predetermined cycle. In step
S1, a camera use status corresponding to the time elapsing between
the previous communication and the present communication with the
secondary battery unit 30, e.g., the number of shutter releases, is
transmitted to the secondary battery unit 30.
[0060] The battery controller 31 at the secondary battery unit 30
executes the processing in FIG. 4(b) upon receiving the camera use
status from the camera main body 10. After receiving the camera use
status corresponding to the time elapsing between the previous
communication and the present communication in step S11, the
operation proceeds to step S12 to add the most recently received
use status to the use status cumulative value stored into the
memory 32 at the time of the previous communication with the camera
main body 10 and stores the sum into the memory 32, thereby
updating the use status cumulative value.
[0061] In the following step S13, the consumed battery capacity
indicating the battery capacity having been used over the time
elapsing between the previous communication and the present
communication is calculated in the method explained earlier. Then,
the most recently calculated consumed capacity is added to the
consumed capacity value stored in the memory 32 at the time of the
previous communication and the sum is stored into the memory 32,
thereby updating the consumed capacity. In step S14, the present
camera use status cumulative value, the consumed battery capacity
and the full charged capacity are read out from the memory 32 and
are transmitted to the camera main body 10.
[0062] In step S2, the camera controller 26 at the camera main body
10 receives the present camera use status cumulative value, the
consumed battery capacity and the full charged capacity from the
secondary battery unit 30. In the following step S3, the ratio of
the present consumed battery capacity to the battery full charged
capacity is calculated to determine the battery use quantity. In
step S4, a verification is executed to ascertain whether or not a
request to display the information related to the secondary battery
unit 30 has been issued through the operation input unit 27, and
the operation proceeds to step S5 if it is determined that a
display request has been issued.
[0063] In step S5, the battery use quantity, i.e., the ratio of the
consumed capacity to the full charged capacity is indicated with a
bar graph and a numerical value (%). In addition, camera use
statuses (work records), i.e., the number of shutter releases and
the use time (the power ON time) in this example, indicating how
the camera has been engaged in operation since the fully charged
battery unit 30 was mounted at the camera main body 10 up to the
current point, are indicated, as shown in FIG. 3.
[0064] Next, an explanation is given on how the secondary battery
unit 30 is charged. FIG. 5 shows the secondary battery unit 30
connected to a charger 40. The charger 40 includes a power circuit
41 which charges the battery cells 34 at the secondary battery unit
30 and also supplies power to the charger 40 itself by rectifying
an AC source voltage, an indicator device 42 such as an LED that
indicates a charge state, a charge controller 43 that manages
charge operations by communicating with the battery controller 31
at the secondary battery unit 30 and an AC plug 44 through which
the connection with the AC source is achieved.
[0065] At the secondary battery unit 30 is connected to the charger
40 and the AC plug 44 is connected to and AC source socket (not
shown), a charge of the battery cells 34 starts. The charge current
flowing from the power circuit 41 at the charger 40 to the battery
cells 34 at the secondary battery unit 30 flows through the
resistor 35, thereby generating a voltage (=charge
current.times.resistance value) in proportion to the level of the
charge current at the two ends of the resistor 35. Thus, as in the
measurement of the consumed capacity as explained earlier, the
charge current can be detected by measuring the voltage at the two
ends of the resistor 35 while charging the secondary battery unit
30 and the charged capacity at the battery cells can be ascertained
through time integration of the charge current. The charged
capacity of the battery cells 34 detected by the capacity
calculation element 33 is transmitted to the charge controller 43
of the charger 40 via the battery controller 31, and the charge
controller 43 manages the charge of the secondary battery unit 30
by controlling the power circuit 41 based upon the charged
capacity.
[0066] As the secondary battery unit 30 is connected to the charger
40, the charge controller 43 outputs a use status clear command to
the memory 32 of the battery controller 31. Upon receiving the use
status clear command, the battery controller 31 resets the use
status cumulative values indicating the number of shutter releases
and the length of power ON time stored in the memory 32 to 0. It is
to be noted that the use status cumulative values stored in the
memory 32 may be reset when the battery controller 31 detects that
the secondary battery unit 30 has been connected to the charger 40,
instead.
[0067] The charge controller 43 makes a decision as to whether or
not the secondary battery cells 34 have been charged to a fully
charged state based upon the charged capacity value transmitted
from the battery controller 31, and once the secondary battery
cells 34 are determined to be in a fully charged state, the
operation of the power circuit 41 is stopped to end the charge
operation and the completion of the charge operation is indicated
at the indicator device 42. The decision as to whether or not the
battery cells have been charged to a fully charged state may be
made by ascertaining whether or not the charged capacity has become
equal to the consumed capacity. Alternatively, the battery cells
may be determined to be in a fully charged state when the charge
current has become equal to or smaller than a predetermined
value.
[0068] Upon the charge completion, the charge controller 43 outputs
a consumed capacity clear command to the battery controller 31 so
as to clear the consumed capacity value stored in the memory 32.
Upon receiving the consumed capacity clear command, the battery
controller 31 resets the consumed capacity value stored in the
memory 32 to 0. It is to be noted that by assuming that the battery
cells are to be charged to the fully charged state once the
secondary battery 30 is connected to the charger 40, the consumed
capacity value in the memory 32 maybe reset automatically for
convenience as the secondary battery unit 30 becomes connected to
the charger 40.
[0069] FIG. 6 presents flowcharts of the charge operation executed
to charge the secondary battery unit. (a) shows the processing
executed at the charge controller 43 of the charger 40, whereas (b)
shows the processing executed at the battery controller 31 of the
secondary battery unit 30.
[0070] The charge controller 43 at the charger 40 makes a decision
in step S21 as to whether or not the secondary battery unit 30 has
been connected. The secondary battery unit 30 is judged to be
connected to the charger 40 if an attempted communication with the
battery controller 31 is enabled. Once the secondary battery unit
30 is determined to be connected to the charger 40, the use status
clear command is transmitted to the battery controller 31 in step
S22.
[0071] Upon receiving the use status clear command from the charge
controller 43, the battery controller 31 of the secondary battery
unit 30 resets the use status cumulative values stored in the
memory 32 to 0 in step S31.
[0072] The charge controller 43 starts charging the battery cells
34 by starting up the power circuit 41 in step S23. As the charge
operation starts, the battery controller 31 starts measuring the
charged capacity with the capacity calculation element 33 in step
S32, and in the following step S33, it transmits the charged
capacity ascertained through the measurement to the charge
controller 43. It is to be noted that the charged capacity may be
measured over predetermined intervals.
[0073] In step S24, the charge controller 43 makes a decision as to
whether or not the battery cells 34 have entered a fully charged
state based upon the charged capacity value transmitted from the
battery controller 31. Once it is confirmed that the battery cells
have been charged to the fully charged state, the operation
proceeds to step S25 to end the charge executed by the power
circuit 41 and the charge completion is indicated at the indicator
device 42. Then, in step S26, the consumed capacity clear command
is transmitted to the battery controller 31.
[0074] Upon receiving the consumed capacity clear command from the
charge controller 43, the battery controller 31 resets the consumed
capacity value stored in the memory 32 to 0 in step S34.
[0075] Since the use status cumulative values and the consumed
capacity value stored in the memory 32 at the secondary battery
unit 30 are reset to 0 every time the secondary battery unit 30 is
charged as described above, the measurement of the use status
cumulative value and consumed capacity can start anew for a fully
charged secondary battery unit 30 with the full charged capacity
after the fully charged secondary battery unit 30 is mounted at the
camera main body 10 upon a charge completion, thereby enabling
detection of accurate battery information.
[0076] As explained above, in the embodiment, the use quantity
representing the extent to which the battery has been consumed from
the fully charged state to the present state relative to the full
charged capacity, i.e., the ratio of battery use and the work
volume (the operation volume) with which the camera has been
engaged in operation from the fully charged state to the present
state are indicated. As a result, it is possible to judge with ease
and accuracy how much more use the user can expect out of the
camera at the present rate of use, i.e., how many more frames of
images can be photographed and how much longer the camera can be
used. Namely, the user can ascertain with ease and accuracy the
available work (operation) volume and work (operation) time
remaining in an apparatus operating on a secondary battery.
[0077] In addition, since the consumed battery capacity and the
camera use status cumulative values (apparatus work volume) are
stored in the secondary battery unit 30, accurate battery
information can be indicated even when the secondary battery unit
30 having been taken out of the camera is reloaded at the
camera.
[0078] Furthermore, since the consumed battery capacity and the
camera use status cumulative values (apparatus work volume) stored
at the secondary battery unit 30 are reset to 0 when the secondary
battery unit 30 is charged, accurate battery information can be
detected and indicated.
[0079] It is to be noted that an explanation is given above in
reference to the embodiment by assuming that the battery cells 34
are charged to the fully charged state during the charge operation
and that the charge capacity value transmitted from the secondary
battery unit 30 to the camera main body 10 is the full charged
capacity. However, as the consumed capacity is stored in the memory
32 of the secondary battery unit 30 and the exact charged capacity
the extent to which the battery cells have been charged can be
ascertained during the charge operation, the accurate charged
battery capacity can be determined even when the charge operation
is halted before the battery cells become fully charged for some
reason, by first subtracting the consumed capacity from the full
charged capacity achieved through the previous charge operation,
thereby ascertaining the remaining battery capacity, and then by
adding the charged capacity achieved through the present charge
operation to the remaining battery capacity. In such a case, the
ratio of the consumed capacity to the charged capacity at the
secondary battery unit 30 at the time of the interrupt in the
charge operation should be ascertained to be indicated with a bar
graph and a numerical value (%) at the camera main body 10. Since
the use quantity relative to the charge capacity of the battery
unit 30 loaded at the camera after the charge operation interrupt
and the camera use statuses (the camera work volume) indicating how
the camera has been engaged in operation on the power supplied from
the secondary battery unit 30 mounted at the camera following the
interrupt in the charge operation can be indicated even when the
charged capacity does not match the full charged capacity, the user
can judge with ease and accuracy how much use he will get out of
the camera at the present rate of use, i.e., how many more pictures
he can take and how much longer he can use the camera.
[0080] Alternatively, if the charge operation is interrupted before
the battery cells become fully charged, the charged capacity having
been achieved by the time of the charge interrupt may be subtracted
from the consumed capacity stored in the memory 32 of the secondary
battery unit 30 so as to determine the ratio of the battery use as
the consumed capacity relative to the full charged capacity as in
the embodiment described earlier.
[0081] In the embodiment described above, the consumed battery
capacity value is transmitted from the secondary battery unit 30 to
the camera main body 10. Instead, the remaining battery capacity
maybe determined by subtracting the consumed capacity from the
charge capacity, and the remaining capacity and the charged
capacity may be transmitted to the camera main body 10. In
addition, while an explanation is given above in reference to the
embodiment on an example in which the ratio of the battery use is
calculated at the camera main body 10 based upon the consumed
battery capacity and the charge capacity, this ratio of battery use
may instead be calculated at the battery unit 30 and the results of
the calculation may be provided to the camera main body 10.
[0082] In the embodiment described above, the number of
photographic frames and the length of use time (the length of power
ON time) are indicated as values indicating the work volume that
the camera has handled. As explained earlier, the level of power
consumption in a camera varies depending upon the specific type of
operation it is engaged in, i.e., depending upon the operating
mode. For instance, more power is required in the photographing
mode in which a photographing operation is executed while
displaying an image at the monitor or in a reproduction mode in
which a photographed image is reproduced at the monitor than in a
regular photographing mode in which an image is photographed
without displaying the image at the monitor. When indicating the
length of time over which the camera has been engaged in operation
after loading a charged battery into the camera, individual lengths
of camera operation time may be indicated separately in
correspondence to the mode in which much power needs to be consumed
such as a monitor image display mode, and the regular photographing
mode so as to allow the user to ascertain how much time the camera
has been engaged in operation in each specific operating mode. As a
result, it becomes possible to judge with ease and accuracy how
long the camera can be used in the operation that the user is
planning to perform on the camera.
[0083] When the individual lengths of camera or apparatus operation
time are indicated for the different operating modes, each
operating mode should be classified in correspondence to the
specific level of power requirement and use status, i.e. the use
time, in the operating mode should be transmitted to the battery
unit from the camera or the apparatus so as to enable the battery
unit to calculate the cumulative values representing the
accumulated length of use time for each operating mode. Then, the
length of use corresponding to the individual operating modes are
transmitted from the battery unit to the camera or the apparatus,
at which the battery use quantity indicating the extent to which
the battery has been used since it was loaded in a charged state
(the ratio of the consumed capacity relative to the charge
capacity), and the lengths of time over which the camera or the
apparatus has been engaged in operation in the various operating
modes are displayed.
[0084] By adopting the embodiment described above, it becomes
possible to allow the user to ascertain with ease and accuracy the
remaining work volume and the remaining work time available in an
apparatus that operates on a battery.
Second Embodiment
[0085] FIGS. 7A and 7B are schematic block diagrams of structures
that may be adopted in the second embodiment of the present
invention. Reference numeral 100 in FIG. 7A indicates a digital
camera (hereafter referred to as a DSC), with reference numeral 110
indicating a DSC function unit that captures a subject image.
Reference numeral 200 indicates a battery pack (battery unit)
loaded into the DSC 100 to supply power to the DSC function unit
110. Reference numeral 300 in FIG. 7B indicates a charge unit used
to charge the battery pack 200. A charging portion 310 of the
charge unit 300 charges the mounted battery pack 200. The battery
pack 200 is taken out of the DSC 100 and is mounted at the charge
unit 300.
[0086] FIG. 8 shows in detail the structure adopted in the DSC 100.
The structural features other than those included in the battery
pack 200 constitute the DSC function unit 110. The DSC function
unit 110 comprises an image-capturing unit 411, an image processing
unit 411A, a monitor display unit 412, a zoom control unit 413, an
AF control unit 414, an AE control unit 415, a light emitting
illumination unit 416, an internal storage unit 170, a medium
recording/reading unit 180, a power control unit 419, a time count
unit 420, a display panel unit 421, a system CPU (hereafter
referred to as a CPU) 430 that is connected with the individual
components and controls the various components and the like. The
image-capturing unit 411 includes a photographic optical system
having an aperture, a shutter, a focusing mechanism, a zoom
mechanism and the like, an image-capturing element and the like.
The image processing unit 411A generates images by processing
signals provided by the image-capturing unit 411. The image
processing unit 411A generates a display image to be displayed at
the monitor display unit 412 and a recording image to be recorded
into the medium recording/reading unit 180. The power control unit
419 controls the power supply from the battery pack 200 to the
individual components. The CPU 430 sets the DSC 100 in a
photographing mode, a reproduction mode or the like, in
correspondence to the setting at the mode selector dial (not shown)
at the DSC 100. The DSC 100 further includes a grounded electrical
terminal at the area where the battery pack 200 is mounted.
[0087] The DSC 100 displays a display image generated by the image
processing unit 411A at the monitor display unit 412 in the
photographing mode. This display image may be the image currently
captured by the image-capturing element or an image which has
already been photographed. The former is used as a view finder
image during a photographing operation. The latter image is
displayed immediately after the photographing operation either
automatically or in response to a specific DSC operation, and the
display screen is switched back to the former image display in
response to a specific operation. The latter image is used to check
the photographing results.
[0088] The zoom control unit 413 implements control on the drive of
the zoom mechanism in response to an operation of a zoom switch
(not shown) by the photographer to adjust the magnification factor
of the subject image captured at the image-capturing element. The
AF control unit 414 adjusts focus on the subject by controlling the
drive of the focusing mechanism. The AE control unit 415 measures
the brightness of the subject and sets an aperture value and a
shutter speed that will achieve the desired exposure quantity in
conformance to the measured brightness level. The light emitting
illumination unit 416 emits light and illuminates the subject when
extra light is needed to achieve the desired exposure based upon
the photometering results obtained at the AE control unit 415.
[0089] The internal storage unit 170 includes an image buffer 171
and a miscellaneous information storage unit 172. The miscellaneous
information storage unit 172 is constituted of a nonvolatile
memory. In the image buffer 171, a recording image generated by the
image processing unit 411A in response to a photographing operation
executed in the DSC 100 is temporarily stored. The medium
recording/reading unit 180 records the photographed image
temporarily stored in the image buffer 171 into a detachable
storage medium 181 loaded therein. In the miscellaneous information
storage unit 172, various conditions set at the DSC 100, e.g.,
basic setting conditions, photographing function conditions and
reproduction function conditions are stored.
[0090] The basic setting conditions include, for instance, the
ON/OFF setting for the operation sound, the auto power OFF time
setting with which the power is automatically turn off when no
operation has been performed over a specific length of time, the
brightness setting for the monitor display unit 412 and the ON/OFF
settings for displaying various types of information at the monitor
display unit 412.
[0091] The photographing function conditions include, for instance,
the monitor display ON/OFF setting, the single AF mode/continuous
AF mode, the multiple area photometering/spot
photometering/centralized photometering setting, the automatic
light emission/forced light emission/no light emission for light
emitting illumination, the image quality mode and the recording
data size, the white balance condition and the monitor display
ON/OFF setting for remaining battery power display. It is to be
noted that in the single AF(S-AF) mode, an auto focus operation is
executed only while the shutter button is pressed halfway down,
whereas an auto focus operation is executed at all times while the
photographing mode is in effect in the continuous AF(C-AF) mode.
The multiple area photometering/spot photometering/centralized
photometering setting is selected to enable the AE control unit to
execute a photometering operation in a specific method. The image
quality mode and the recording image size are set to determine
specific image processing conditions under which the image
processing unit 411A generates a recording image, e.g., the image
compression rate and the image size.
[0092] The various conditions stored in the miscellaneous condition
storage unit are each selected from options corresponding to a
given function condition. The control unit 430 photographs an image
in the photographing mode or displays a photographic image in the
reproduction mode by controlling the various components in
conformance to the individual function condition settings stored in
the miscellaneous information storage unit 172.
[0093] In addition, one of the options corresponding to each
condition is stored in the miscellaneous information storage unit
172 as an initial basic setting condition, an initial photographing
function condition or an initial reproduction function
condition.
[0094] The time count unit 420 is capable of individually counting
the lengths of different types of continuous time periods and
various accumulated time lengths each representing a cumulative
value of a plurality of time periods corresponding to a given
type.
[0095] The DSC 100 reads out an image recorded in the storage
medium 181 and displays the image thus read out at the monitor
display unit 412 in the reproduction mode.
[0096] The battery pack 200 includes a secondary battery 201, a
measurement unit 202, a means for storage 203, a CPU 204, a
charge/discharge control unit 206 and an indicator unit 207. The
secondary battery 201 is a rechargeable battery which may be, for
instance, a lithium ion battery, a nickel hydrogen battery or a
nickel cadmium battery. In the means for storage 203, information
indicating the remaining battery power (rated value) when the
secondary battery 201 is in a fully charged state, the remaining
battery power at the end of a charge operation, the remaining
battery power currently available in the battery (hereafter may be
simply referred to as the remaining battery power) and the like is
stored. The CPU 204 to which the measurement unit 202, the means
for storage 203, the charge/discharge control unit 206 and the
indicator unit 207 are connected, is driven by the secondary
battery 201. The measurement unit 202 measures the voltage and the
current output from the secondary battery 201 or the voltage and
the current input to the secondary battery 201, as well as the
battery temperature.
[0097] The CPU 204, which also functions as part of the measurement
unit 202, calculates the quantity of electricity flowing out from
the secondary battery 201 based upon the output voltage and the
output current, calculates the quantity of electricity flowing into
the secondary battery 201 based upon the input voltage and the
input current, determines a new value indicating the remaining
battery power, i.e., the quantity of electricity that can be output
subsequently, based upon the present value of the remaining battery
power stored in the means for storage 203 and the quantities of
electricity outflow/inflow, and updates the remaining battery power
at the means for storage 203 with the new value for the remaining
battery power. The remaining battery power is calculated by
incorporating a temperature compensation based upon the battery
temperature measured by the measurement unit 202, since the
remaining battery power value increases as the battery temperature
rises and decreases as the battery temperature falls. In addition,
the ratio of the current remaining battery power to the remaining
battery power when the secondary battery 201 is in the fully
charged state, i.e., the charge rate, is determined to update the
outstanding charge rate stored in memory.
[0098] The charge/discharge control unit 206 starts/stops the power
supply from the secondary battery 201 to the outside and a charge
of the secondary battery 201 in response to commands issued from
the CPU 204.
[0099] At the indicator unit 207, the state of the battery pack 200
and the like are indicated in response to a command from the CPU
204. The state of the battery pack 200 includes the remaining
battery power and the charge rate mentioned earlier.
[0100] The battery pack 200 further includes a means for mount
detection 205 that is utilized to detect the apparatus into which
the battery pack 200 is mounted. The means for mount detection 205
has an electrical terminal which is connected to an electrical
terminal of the apparatus at which the battery pack 200 is mounted
and detects the potential at the electrical terminal. Based upon
the detected potential, the CPU 204 detects the apparatus into
which the battery pack 200 has been loaded. The grounded electrical
terminal at the DSC 100 is connected to the electrical terminal of
the means for mount detection 205.
[0101] The CPU 204 at the battery pack 200 and the CPU 430 at the
DSC 100 into which the battery pack 200 is mounted exchange various
types of information. The CPU 430 obtains the information
indicating the remaining battery power stored at the means for
storage 203 via the CPU 204 and displays the obtained information
at the display panel unit 421. Depending upon the display condition
set at the DSC 100, the information may also be displayed at the
monitor display unit 412. The information displayed at the monitor
display unit 412 may be superimposed over a display image.
[0102] FIG. 9 shows in detail the charge unit 300. The charging
portion 310 at the charge unit 300 includes a charge circuit 311, a
charge control unit 312 and a CPU 313. The CPU 313 issues commands
for the charge control unit 312 to control the charge circuit 311
and also exchanges various types of communication with the CPU 204
at the battery pack 200 mounted at a specific position of the
charge unit 300. The battery pack 200 mounted at the specific
position of the charge unit 300 is charged by the charging portion
310. The charge circuit 311 receives power from a commercial source
and supplies a voltage/current suitable for charging the secondary
battery 201 to the battery pack 200. The charge control unit 312
includes an electrical terminal which is connected to the
electrical terminal of the means for mount detection 205 at the
battery pack 200 mounted at the charge unit 300. A predetermined
level of potential is achieved at the electrical terminal of the
charge control unit 312.
[0103] The CPU 204 of the battery pack 200 constantly monitors the
electrical potential at the electrical terminal of the means for
mount detection 205 over a predetermined cycle. If the detected
potential is 0 V, the CPU 204 judges that the battery pack is
mounted in the DSC 100, whereas it judges that the battery pack 200
is mounted at the charge unit 300 if the detected potential is at
the predetermined level. If no potential is detected, the CPU 204
judges that the battery pack 200 is not mounted at any apparatus.
If the battery pack 200 is judged to be loaded in the DSC 100, the
CPU 204 issues a command for the charge/discharge control unit 206
to start power supply from the secondary battery 201. To be more
precise, the actual power supply starts when the power switch at
the DSC 100 is turned on. If the battery pack 200 is judged to be
mounted at the charge unit 300, the CPU 204 issues a command for
the charge/discharge control unit 206 to enable a charge of the
secondary battery 201. Since the detection and judgment are
executed constantly, the CPU 204 is able to sense a disengagement
of the battery pack from the apparatus at which the battery pack
200 has been mounted, as well. Then, its stores the remaining
battery power at the time of the disengagement into the means for
storage 203 as the remaining battery power at the charge end.
Subsequently, it issues a command for the charge/discharge control
unit 206 to cut off the terminal used for power supply/charge from
the internal circuits of the battery pack 200, thereby disabling
the power supply/charge. As a result, it is possible to prevent
shorting.
[0104] Next, the internal operation of the DSC 100 is explained by
focusing on the processing executed by the CPU 430. FIGS. 10 and 11
present a flowchart of the processing executed at the CPU 430.
While the procedure shown in FIG. 10 and the procedure shown in
FIG. 11 are both part of a single procedural sequence, they are
presented in two separate drawings for convenience. The explanation
is first given in reference to FIG. 10. The processing in FIG. 10
starts as the power switch at the DSC 100 is turned on.
[0105] In step S101, the remaining battery power R is read from the
means for storage 203 at the battery pack 200. At the same time,
the remaining battery power at the charge end is also read and
stored into the miscellaneous information storage unit 172. If a
value representing the remaining battery power is already stored in
the miscellaneous information storage unit 172, the value is
updated. It is to be noted that the read of the DSC information
indicated inside the parentheses of step 101 is to be explained in
detail later.
[0106] In step S102, a decision is made as to whether or not the
remaining battery power R having been read is equal to or greater
than a first predetermined value at which at least some of the
functions of the DSC 100 can be engaged in operation. If it is
decided that the remaining battery power R is equal to or greater
than the first predetermined value, the operation proceeds to step
S103, whereas the operation proceeds to step S113 if the remaining
battery power is determined to be less than the first predetermined
value. After an error message such as "insufficient battery power"
is displayed over a predetermined length of time in step S113, the
power switch is turned off in step S114 and then the processing
ends.
[0107] In step S103, the various components of the DSC 100 are set
to the basic initial settings. The basic initial setting conditions
stored in the miscellaneous information storage unit 172 are used
as the basic initial settings. A basic initial setting condition
selected as an initial setting of the DSC 100 can be altered by
performing a specific operation at the DSC 100. Then, by performing
a further specific operation, the basic initial setting condition
stored in the miscellaneous information storage unit 172 is updated
to the new condition setting.
[0108] In step S104, the time count unit 420 starts a first time
count. In the first time count, the time count unit 420 measures
the length of time over which the DSC 100 is engaged in operation
(the DSC operation time). The time count of the DSC operation time
continues until the power switch of the DSC 100 is turned off. A
further explanation is given in reference to FIG. 11.
[0109] In step S105, the mode having been set through the mode
selector dial which is operated to select an operating mode for the
DSC 100 is judged and the operation proceeds to execute the
processing corresponding to the specific mode setting. For
instance, if the photographing mode has been set in the DSC, the
operation proceeds to step S106, whereas if the reproduction mode
has been set, the operation proceeds to step S116.
[0110] In step S106, the DSC 100 is started up in the photographing
mode. The processing executed in step S106 is to be described in
detail later.
[0111] In step S107, the DSC 100 executes photographing mode
processing, i.e., it executes the various functions needed to
photograph images in response to a DSC operation performed by the
photographer.
[0112] In step S108, a decision is made as to whether or not the
photographing mode is to be sustained. If the photographing mode is
still set at the mode selector dial, the photographing mode is
judged to be still in effect and accordingly, the operation returns
to step S107 to continue with the photographing mode processing.
If, on the other hand, it is decided that the photographing mode is
no longer in effect, the operation proceeds to step S109. It is
judged that the photographing mode is no longer in effect if the
mode selector dial setting has been changed to another mode, e.g.,
the reproduction mode.
[0113] In step S109, photographing mode end processing is executed.
Processing similar to that executed to exit the photographing mode
in a DSC in the related art is executed as the photographing mode
end processing. Since the details of this processing are of the
known art, their explanation is omitted. It is to be noted that if
the power switch of the DSC 100 is turned off in the photographing
mode, the processing in step S109 is executed in response to an
interrupt command 50 generated and input in response to the power
OFF.
[0114] In step S110, a decision is made as to whether or not the
power switch has been turned off, i.e., whether or not the
interrupt command 50 has been input. If an interrupt command has
been input, the operation proceeds to step S130 to execute end
processing similar to that executed in DSCs in the related art and
turn off the power. Otherwise, the operation returns to step S105
after reading the remaining battery power R in step S111, to engage
in startup processing for the mode newly selected through the mode
selector dial. For instance, if the setting at the mode selector
dial has been switched to the reproduction mode, the operation
proceeds to step S116.
[0115] If, on the hand, it is judged in step S105 that the
reproduction mode is set at the mode selector dial, the DSC 100 is
started up in the reproduction mode in step S116. The processing
executed in step S116 is to be described in detail later.
[0116] Instep S117, the DSC 100 executes the reproduction mode
processing, i.e., it executes various functions related to
photographic image reproduction in response to a DSC operation
performed by the photographer.
[0117] In step S118, a decision is made as to whether or not the
reproduction mode is to be sustained. If the mode selector dial is
still set at the reproduction mode, it is judged that the
reproduction mode is to be sustained, and the operation returns to
step S117 to continuously execute the reproduction mode processing.
If, on the other hand, it is judged that the reproduction mode is
no longer in effect, the operation proceeds to step S119. It is
judged that the reproduction mode is no longer in effect if the
setting at the mode selector dial has been switched to another mode
such as the photographing mode.
[0118] In step S119, reproduction mode end processing is executed.
Processing similar to that executed to exit the reproduction mode
in a DSC in the related art is executed as the reproduction mode
end processing. Since the details of this processing are of the
known art, their explanation is omitted. It is to be noted that if
the power switch of the DSC 100 is turned off in the reproduction
mode, the processing in step S119 is executed in response to an
interrupt command 50 generated and input in response to the power
OFF.
[0119] In step S120, a decision is made as to whether or not the
power switch has been turned off. If the power switch is judged to
have been turned off, the operation proceeds to step S130 to
execute end processing by turning off the power. The end processing
is to be described in detail later. Otherwise, after reading the
remaining battery power R in step S121, the operation returns to
step S105 to execute startup processing for the new mode selected
with the mode selector dial. For instance, if the photographing
mode has been selected with the mode selector dial, the operation
proceeds to step S106.
[0120] The procedure of the photographing mode startup processing
executed in step S106 and the procedure of the reproduction mode
startup processing executed in step S116 are respectively shown in
FIGS. 12 and 13.
[0121] It is to be noted that instead of or in addition to reading
the remaining battery power in steps S111 and S121, the remaining
battery power R may be read at the end of each type of processing
or at the ends of certain types of processing executed in the
photographing mode or the reproduction mode, which requires a great
deal of battery power, e.g., photographing processing executed in
response to a full-press operation of the shutter button and a
light emission at the light emitting illumination unit 416 in the
photographing mode, and display image selection processing in the
reproduction mode. In such a case, a higher level of accuracy is
achieved in the remaining battery power display which is to be
explained in reference to FIGS. 12 and 13. Upon starting the
photographing mode startup processing in FIG. 12 (step S106 in FIG.
11), the CPU 430 executes initial setting for photographing mode
initialization instep S201. The initial photographing function
conditions stored in the miscellaneous information storage unit 172
are used as the initial settings in the photographing mode. As
explained earlier, the photographing function conditions include
the monitor display ON/OFF setting, the single AF mode/continuous
AF mode setting, the multiple area photometering/spot
photometering/centralized photometering setting, the automatic
light emission/forced light emission/no light emission setting for
light emitting illumination, the image quality mode and the
recording data size, the white balance condition and the monitor
display ON/OFF setting for the remaining battery power display. In
this example, the first option among the options for each condition
distinguished from each other with a "/" is stored in the
miscellaneous information storage unit 172 as the initial
photographing function condition.
[0122] A given photographic function condition selected as an
initial setting at the DSC 100 can be altered through a subsequent
specific operation performed at the DSC 100 in the photographing
mode. Then, by performing a further specific operation, the initial
photographing function condition stored in the miscellaneous
information storage unit 172 is updated to the new condition
setting.
[0123] In step S202, the DSC 100 is started up in conformance to
the photographing function conditions selected as the initial
settings as explained above. At this time, the monitor display unit
412 is set in an ON state or an OFF state depending upon the
monitor display unit ON/OFF condition which is one of the
photographing function conditions and the remaining battery power
R. Namely, a decision is made as to whether the monitor display
unit ON setting or the monitor display unit OFF setting is
currently selected. If the ON setting is in effect, the operation
proceeds to step S204, whereas if the OFF setting is in effect, the
operation proceeds to step S207.
[0124] Instep S204, a decision is made based upon the remaining
battery power R read in step S101 in FIG. 10 or in step S111 or
step S121 in FIG. 11. The remaining battery power R read in step
S111 or S121 in FIG. 11 is lower than the remaining battery power R
read in step S101 in FIG. 10, since the battery power is further
consumed in the DSC 100 between step S101 and step S111 or between
step S101 and step S121.
[0125] The operation proceeds to step S205 if the remaining battery
power R is equal to or greater than a second predetermined value
indicating the battery power needed to photograph an image by
engaging the monitor display unit 412, whereas the operation
proceeds to step S225 if the remaining battery power R is less than
the second predetermined value but it is equal to or greater than a
third predetermined value indicating the battery power with which
an image can be photographed as long as the monitor display unit
412 is not engaged to turn off the monitor display unit 412 and
then a message indicating that the battery no longer has enough
power to enable a photographing operation performed by engaging the
monitor display unit 412 is brought up at the display panel unit 21
in step S226 before the operation proceeds to step S207. It is to
be noted that the second predetermined value is larger than the
first predetermined value mentioned earlier. If the remaining
battery power R is determined to be less than the third
predetermined value, the operation proceeds to step S215 to turn
off the monitor display unit 412 and then, in step S216, an error
message is displayed to indicate that a photographing operation is
disabled due to insufficient battery power is displayed at the
display panel 21 before the processing ends.
[0126] In step S205, the time count unit 420 starts a second time
count. In the second time count, the accumulated length of time
(accumulated monitor ON time) over which the monitor display unit
412 is engaged in operation (monitor ON time) is measured. The
monitor ON time is measured (the monitor ON count is sustained)
until the photographing mode ends or until the power switch of the
DSC 100 is turned off. If the monitor display unit 412 is turned
off in the photographing mode, the monitor ON count is halted, and
then the time count is resumed as the monitor display unit 412 is
turned on again so as to measure the accumulated monitor ON
time.
[0127] As explained later, the length of time over which the
monitor display unit is set in an ON state is also measured during
the reproduction mode processing. The accumulated length of time
over which the monitor display unit remains in an ON state includes
the monitor ON time measured during the reproduction mode
processing as well. Namely, the cumulative value represents the
overall length of time over which the monitor is in an ON state
after the power switch of the DSC 100 is turned on.
[0128] Instep S206, the remaining battery power R is displayed at
the monitor display unit 412.
[0129] Instep S207, the remaining battery power R is displayed at
the display panel unit 21.
[0130] After executing the photographing mode startup procedure
described above, the photographing mode processing in step S107 in
FIG. 11 is executed.
[0131] The photographing mode processing (executed in step S107 in
FIG. 11) is now explained. During the photographing mode
processing, processing similar to that executed during a
photographing operation in a DSC in the related art is executed.
While the processing which is of the known art is not explained in
detail, an image captured by the image-capturing unit 411, for
instance, is displayed in real time at the monitor display unit 412
during the photographing mode processing. This display image is
used as a view finder image. If the monitor display OFF setting has
been selected, the display image is not displayed.
[0132] As the shutter button (not shown) at the DSC is pressed
halfway down, AF processing and photometering processing are
respectively executed by the AF control unit 414 and the AE control
unit 415, and in response to a full-press operation of the shutter
button, photographing processing is executed. Namely, in response
to a halfway press operation of the shutter button, the focus is
adjusted on to the subject by the AF control unit 414, the AE
control unit 415 sets the aperture and the shutter speed to values
selected based upon the results of the photometering processing and
light is emitted at the light emitting illumination unit 416 as
necessary. In addition, a recording image together with a display
image for reproduction and a thumbnail image corresponding to the
recording image is generated at the image processing unit 411A by
using the image photographed in response to a full-press operation
of the shutter button, and the images are stored into the image
buffer 171 and are also recorded into the recording medium 181 at
the medium recording/reading unit 180. The recording image is an
image having undergone processing executed at the image quality
mode setting, the recording data size setting and the white balance
condition setting selected as part of the photographing function
conditions explained earlier. The reproduction display image is a
small-size image generated in conformance to the performance level
of the monitor display unit 412 and the thumbnail image is an even
smaller image for thumbnail display.
[0133] It is to be noted that if the remaining battery power R is
read at the end of each type of processing or at the ends of
certain types of processing executed in the photographing mode
processing or the reproduction mode processing, the processing in
step S204 and subsequent steps in FIG. 12 or the processing in step
S303 and subsequent steps in FIG. 13, too, should be executed each
time the remaining battery power R is read.
[0134] Upon starting the reproduction mode startup processing in
FIG. 13 (step S116 in FIG. 11), the CPU 430 executes initial
setting for the initialization for the reproduction mode in step
S301. The initial reproduction function conditions stored in the
miscellaneous information storage unit 172 are used as the initial
settings in the reproduction mode. The reproduction function
conditions include the number of images to be brought up on display
together in thumbnail image display and the length of time
intervals over which a plurality of images are to be reproduced
continuously, for example. An initial reproduction function
condition selected as an initial setting at the DSC 100 can be
altered by performing a subsequent specific operation performed at
the DSC 100 in the reproduction mode. Then, by performing a further
specific operation, the initial reproduction function condition
stored in the miscellaneous information storage unit 172 is updated
to the new condition setting.
[0135] In step S302, the DSC 100 is started up in conformance to
the reproduction function conditions selected as the initial
settings as explained above. At this time, the monitor display unit
412 is set in an ON state or an OFF state depending upon the
remaining battery power R. Namely, in step S303, a decision is made
as to whether or not the remaining battery power R read in step
S101 in FIG. 10 or in step S111 or step S121 in FIG. 11 is equal to
or greater than a fourth predetermined value indicating the battery
power that enables the execution of the operation in the
reproduction mode. The remaining battery power R read in step S111
or S121 in FIG. 11 is lower than the remaining battery power R read
in step S101 in FIG. 10, since the battery power is further
consumed in the DSC 100 between step S101 and step S111 or between
step S101 step S121. The operation proceeds to step S304 if the
remaining battery power is determined to be equal to or greater
than the fourth predetermined value, whereas the operation proceeds
to step S3014 if it is judged to be less than the fourth
predetermined value.
[0136] In step S304, the time count unit 420 starts a second time
count, i.e., the time count of the accumulated length of monitor ON
time. The monitor ON time is measured (the monitor ON count is
sustained) until the reproduction mode ends or until the power
switch of the DSC 100 is turned off.
[0137] As explained earlier, the length of time over which the
monitor display unit remains in an ON state is also measured during
the photographing mode processing. The accumulated length of time
over which the monitor display unit is in an ON state includes the
monitor ON time measured during the photographing mode processing,
as well. Namely, the cumulative value represents the overall length
of time over which the monitor is in an ON state after the power
switch of the DSC 100 is turned on.
[0138] In step S305, the remaining battery power R is displayed at
the monitor display unit 412.
[0139] In step S306, the remaining battery power R is displayed at
the display panel unit 21.
[0140] By executing the reproduction mode startup procedure
described above, the DSC 100 is set in a photographic image
reproduction enabled state.
[0141] The following processing is executed if the remaining
battery power R is judged to be less than the fourth predetermined
value in step S303.
[0142] The monitor display unit 412 is turned off in step S314, and
the remaining battery power R is displayed at the display panel
unit 21 in step S315. In step S316, an error message indicating
that the remaining battery power is insufficient is displayed
before the processing ends.
[0143] Next, the reproduction mode processing (executed in step
S117 in FIG. 11) is explained. During the reproduction mode
processing, processing similar to that executed during a
reproduction operation in a DSC in the related art is executed.
While the processing which is of the known art is not explained in
detail, an image recorded in the storage medium 181, for instance,
is read out and displayed at the monitor display unit 412. At this
time, the specific number of thumbnail images generated in
correspondence to individual recording images, which number is set
as a reproduction function condition, is displayed at once. The
user is then prompted to select any image among the thumbnail
images by performing a specific operation and then the reproduction
image corresponding to the selected image is brought up on display.
In addition, a flag indicating whether or not the recording image
corresponding to the display image needs to be printed can be set.
The photographing conditions under which the image on display was
photographed and the like may be superimposed on the display as
well.
[0144] Information related to the DSC is stored in the means for
storage 203 in the embodiment. The DSC-related information is
stored by the CPU 430 during the end processing executed in the DSC
100. The DSC-related information includes the accumulated length of
time over which the shutter button has been pressed halfway down,
the number of photographs having been taken, the number of times at
which light has been emitted at the light emitting illumination
unit 416, the accumulated length of time over which the zoom has
been engaged, the length of time over which the monitor has been in
an ON state and the length of time over which the DSC has been
engaged in operation. It is to be noted that the DSC-related
information is stored at the means for storage 203 is reset when
the secondary battery 201 becomes charge to a sufficient extent,
e.g., to an extent equal to or greater than the charge rate of 85%.
Then, the CPU 430 at the DSC 100 executes processing such as that
shown in FIG. 14 on the DSC-related information. Namely, the
DSC-related information is read out from the means for storage 203
and is stored into the miscellaneous information storage unit 172
as read information in step S401. This processing is executed when
reading the remaining battery power in step S101 in FIG. 10.
[0145] Instep S402, the time count unit 420 measures the length of
time over which the shutter button has been pressed halfway down
(halfway press time), and the cumulative value indicating the
accumulated length of time over which the shutter button has been
pressed halfway down is stored into the miscellaneous information
storage unit 172 as most recent information. It is desirable to
include the length of time over which the shutter button has been
pressed all the way down in the accumulated halfway press time. The
cumulative value may be calculated by, for instance, the CPU 430.
It is to be noted that if the continuous AF mode setting has been
selected as a photographing function condition, the accumulated
length of time over which the photographing mode has been sustained
is stored into the miscellaneous information storage unit 172, as
well.
[0146] In addition, the number of times the shutter button has been
pressed all the way down, i.e., the number of photographs taken, is
counted and the count value is stored into the miscellaneous
information storage unit 172 as most recent information. The number
of times at which light has been emitted at the light emitting
illumination unit 416 is also counted and the count value is stored
into the miscellaneous information storage unit 172 as most recent
information. The time count unit 420 measures the length of time
over which the zoom control unit for 13 has been engaged in
operation (zoom operation time) and the value indicating the
accumulated length of time over which the zoom control unit has
been engaged in operation is stored into the miscellaneous
information storage unit 172 as most recent information.
[0147] The storage of the most recent information is executed
whenever necessary as various operations are performed at the DSC
100 and the various functions of the DSC 100 are engaged. However,
the accumulated length of halfway press time and the accumulated
length of zoom operation time may be simply measured at the time
count unit 420.
[0148] In step S403, the sums of the values indicated in the
information having been read and the values indicated in the most
recent information are obtained as present information indicating
the present state of the DSC.
[0149] The processing in steps S402 and S403 is executed
concurrently with the photographing mode processing in step S107 in
FIG. 11 and the reproduction mode processing in step S117 in FIG.
11.
[0150] In step S404, a decision is made as to whether or not the
power switch has been turned off, and the operation returns to step
S402 if it is decided that the power switch has not been turned off
whereas the operation proceeds to step S405 if it is decided that
the power switch has been turned off.
[0151] In step S405, the present information is provided to the CPU
204 at the battery pack 200. Then, the present information is used
to update the DSC-related information stored in the means for
storage 203 via the CPU 204.
[0152] In step S406, the values having been measured at the time
count unit 420 and the values stored in the miscellaneous
information storage unit 172 are all reset to 0.
[0153] The processing in steps S405 and S406 is executed
concurrently with the end processing in step S130 in FIG. 11.
[0154] Since the DSC-related information stored at the battery pack
200 is reset as the secondary battery 201 becomes charged, the
DSC-related information stored at the means for storage 203
indicates the accumulated length of halfway press time, the number
of photographs having been taken, the number of times at which
light has been emitted at the light emitting illumination unit 416,
the accumulated length of zoom operation time, the length of time
over which the monitor has been on and the length of time over
which the DSC has been engaged in operation after the battery pack
200 was charged most recently.
[0155] The DSC 100 executes processing by using the DSC-related
information to provide various types of information useful to the
user of the DSC 100. This processing is to be described in detail
later.
[0156] It is to be noted that the remaining battery power R alone
may be initially read and the DSC-related information may be read
only if the remaining battery power R is judged to be equal to or
greater than the first predetermined value or the third
predetermined, instead.
[0157] An example of the useful information that may be provided to
the user of the DSC 100 based upon the DSC-related information is
now explained.
[0158] The CPU 430 reads the remaining battery power R in response
to a specific operation performed at the DSC 100. Then, based upon
consumed battery power ascertained in correspondence to the
remaining battery power at the charge end read in step S101 in FIG.
10 and the remaining battery power R and the number of photographs
having been taken indicated in the present information, the
consumed battery capacity quantity (performance value) per single
photographed image is calculated. And a number of photographs that
can be taken is estimated by using the consumed battery capacity
quantity per single photographed image and is displayed at the
monitor display unit 412. The estimated value is stored into the
means for storage 203 via the CPU 204 of the battery pack 200 and
it also is indicated at the indicator unit 207. Thus, the user can
ascertain the estimated number of photographs that can be taken by
checking the value indicated at the indicator unit 207, even when
the battery pack 200 is disengaged from the DSC 100. If the user
has a plurality of battery packs, he can choose a battery pack with
a sufficient level of battery power remaining to take the desired
number of pictures.
[0159] The battery power needed to photograph a single image
fluctuates depending upon the length of time over which the display
monitor 412 remains in an ON state while photographing the image
(which is affected by the length of time required to determine the
composition and the length of time required to check the
photographic image), the length of time over which the shutter
button is held halfway down (corresponding to the length of time
over which the AF operation is executed), the length of time over
which the zoom operation is executed and the like. These time
lengths and the frequency with which the corresponding components
are engaged in operation tend to vary among individual
photographers. The need to emit light with the light emitting
illumination unit 416 arises when photographing images at a
specific time of day or under specific lighting conditions. For
this reason, as long as a given photographer keeps taking
photographs with a photographing pattern similar to the previous
photographing pattern, the battery power needed to photograph a
single image does not change much. Under such circumstances, the
estimated value will prove useful to the user.
[0160] While the number of images that can be photographed may be
calculated based upon the theoretical power consumption quantity
corresponding to the standard photographing behavior pattern
anticipated by the digital camera manufacturer, the estimated value
obtained based upon the actual number of photographed images and
the corresponding consumed battery power (the performance value) in
the embodiment described above achieves a higher degree of accuracy
by reflecting the photographing behavior pattern of the specific
photographer.
[0161] The CPU 430 reads and checks the remaining battery power R
when the power to the DSC 100 is turned on. The CPU 430 calculates
the estimated value at this point, too, if the remaining battery
power R is less than a predetermined value and displays the
estimated value at the monitor display unit 412 and the display
panel unit 21 to warn the user that the battery power R is running
low. It will be particularly effective to warn the user by
superimposing the estimated value over a photographic image
displayed at the monitor display unit 412. If the remaining battery
power is equal to or greater than the predetermined value, the
processing ends without estimating the number of images that can be
photographed, since a sufficient level of battery power is still
available and the user can take photographs without worrying about
the battery power running low.
[0162] In addition, the number of images that can be photographed
is also estimated in the end processing (executed in step S130 in
FIG. 11). It is desirable to provide a non-visual warning such as a
warning sound or a warning vibration together with the display of
the number of images that can be photographed. Since the user can
verify how many more image as can be taken on the remaining battery
power when ending use of the DSC 100, he is able to make an
accurate judgment as to whether or not the battery pack 200 needs
to be charged before he next uses the DSC 100. Thus, the user can
prevent a trouble in which he can not perform a desired
photographing operation due to a depleted battery when he is ready
to use the DSC 100. It is desirable to indicate the number of
images that can be photographed having been estimated during the
end processing at the indicator unit 207 as described earlier,
regardless of whether a large number of images or a small number of
images can be photographed on the remaining battery power.
Moreover, the number of images that can be photographed having been
estimated during the end processing may be indicated at an
indicator unit 207 of a battery pack 200 which is used in a silver
halide film camera instead of a DSC, by adopting the processing
principal explained above, to achieve similar advantages.
[0163] FIG. 15 presents an example of a display that may be brought
up at the monitor display unit to indicate varying numbers of
images that can be photographed under different photographing
conditions.
[0164] The above described embodiments are examples, and various
modifications can be made without departing from the spirit and
scope of the invention.
* * * * *