Title: Shutter abnormality detection apparatus for camera
Abstract: A shutter abnormality detection apparatus for a camera includes a shutter including leading and trailing curtains which are shutter curtains electrically controlled to run. A curtain run detection unit detects a run state of at least one of the leading and trailing curtains. A curtain run time judgment unit judges a run time of the shutter curtains based on an output from the curtain run detection unit. An abnormality processing unit notifies an abnormality state of the shutter curtains, when it is judged as a result of judgment in the curtain run time judgment unit that the curtain run time is abnormal.
Patent Number: 6,871,019 Issued on 03/22/2005 to Matsumoto, et al.
| Inventors:
|
Matsumoto; Hisayuki (Hachioji, JP);
Okumura; Yoichiro (Hino, JP);
Ishimaru; Toshiaki (Hino, JP)
|
| Assignee:
|
Olympus Corporation (Tokyo, JP)
|
| Appl. No.:
|
436533 |
| Filed:
|
May 13, 2003 |
Foreign Application Priority Data
| May 15, 2002[JP] | 2002-140274 |
| Jun 17, 2002[JP] | 2002-175881 |
| Current U.S. Class: |
396/235; 396/479 |
| Intern'l Class: |
G03B 007//00 |
| Field of Search: |
396/235,236,479-482
|
References Cited [Referenced By]
U.S. Patent Documents
Primary Examiner: Gray; David M.
Attorney, Agent or Firm: Volpe and Koenig, P.C.
Claims
What is claimed is:
1. A shutter abnormality detection apparatus for a camera comprising a
shutter including leading and trailing curtains which are shutter curtains
electrically controlled to run, the apparatus comprising:
a curtain run detection unit which detects a run state of at least one of
the leading and trailing curtains;
a curtain run time judgment unit which judges a run time of the shutter
curtains based on an output from the curtain run detection unit; and
an abnormality processing unit which notifies an abnormality state of the
shutter curtains, when it is judged as a result of judgment in the curtain
run time judgment unit that the curtain run time is abnormal;
wherein the said abnormality processing unit including an operation lock
function which locks the subsequent operation of the camera, when the
curtain run time is judged to be abnormal; and further comprising:
a return unit which returns the operation of the camera from the locked
state in response to a predetermined operation, when the subsequent
operation of the camera is locked by the abnormality processing unit;
a curtain run time recheck unit which again judges whether or not the run
time of the shutter curtain is normal during the operation of return by
the return unit; and
a control unit which returns the operation of the camera to a normal
operation, when the run time of the shutter curtain is judged to be normal
as a result of judgment by the curtain run time recheck unit and which
controls and locks the subsequent operation of the camera, when the run
time of the shutter curtain is again judged to be abnormal.
2. The shutter abnormality detection apparatus for the camera according to
claim 1, wherein the predetermined operation includes an operation of a
power switch or an attachment/detachment operation of a power battery.
3. The shutter abnormality detection apparatus for the camera according to
claim 1, wherein the curtain run time recheck unit controls the operation
so that the trailing curtain starts running ahead of the leading curtain
so as to prevent a useless exposure operation.
4. A shutter abnormality detection apparatus for a camera comprising a
shutter including leading and trailing curtains which are electrically
controlled to run, the apparatus comprising:
a leading curtain run detection unit which outputs a run completion signal
of the leading curtain of the shutter;
a trailing curtain run detection unit which outputs the run completion
signal of the trailing curtain of the shutter; and
a shutter abnormality judgment unit which detects a state of the run
completion signal outputted from the other curtain run detection unit
based on the run completion signal from either one of the leading and
trailing curtain run detection units and which judges abnormality of the
shutter based on a detection result, wherein the shutter abnormality
judgment unit judges that the shutter is abnormal, when the leading
curtain run detection unit outputs a run incompletion signal at an output
time of the run completion signal of the trailing curtain run detection
unit or when the trailing curtain run detection unit outputs the run
completion signal at the output time of the run completion signal of the
leading curtain run detection unit.
5. A shutter abnormality detection apparatus for a camera comprising a
shutter including leading and trailing curtains which are electrically
controlled to run, the apparatus comprising:
a leading curtain run detection unit which outputs a run completion signal
of the leading curtain of the shutter;
a trailing curtain run detection unit which outputs the run completion
signal of the trailing curtain of the shutter; and
a shutter abnormality judgment unit which detects a state of the run
completion signal outputted from the other curtain run detection unit
based on the run completion signal from either one of the leading and
trailing curtain run detection units and which judges abnormality of the
shutter based on a detection result, and further comprising:
a shutter speed calculation unit which calculates an opening time of the
shutter based on an object luminance; and
a prohibition unit which prohibits an operation of the shutter abnormality
judgment unit, when the shutter speed is lower than a predetermined speed.
6. A shutter abnormality detection apparatus for a camera comprising a
shutter including leading and trailing curtains which are shutter curtains
electrically controlled to run, the apparatus comprising:
a first detection unit which detects a change of a level of a signal
indicating a run state of the leading curtain of the shutter;
a second detection unit which detects the change of the level of the signal
indicating the run state of the trailing curtain of the shutter; and
a shutter abnormality judgment unit which compares a detection timing of
the level change by the first detection unit with that of the level change
by the second detection unit and which judges that the run of the shutter
curtain is abnormal, when the detection timing of the level change by the
second detection unit is earlier than that of the level change by the
first detection unit.
7. A shutter abnormality detection apparatus for a camera comprising a
shutter including leading and trailing curtains which are shutter curtains
electrically controlled to run, the apparatus comprising:
a strobe unit which irradiates an object;
a shutter abnormality judgment unit which judges whether or not the shutter
is abnormal based on a run state of the shutter curtain;
a flat light emitting unit which allows the strobe unit to emit light in a
flat state from start of an opening operation of the shutter until the
shutter is closed; and
a prohibition unit which prohibits the operation of the shutter abnormality
judgment unit, when the flat light emitting unit is controlled.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority from the
prior Japanese Patent Applications No. 2002-140274, filed May 15, 2002 and
2002-175881, filed Jun. 17, 2002, the entire contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a shutter abnormality detection apparatus
for a camera.
2. Description of the Related Art
A camera on which a focal plane shutter is mounted has heretofore been
known. In this camera, an electric control type shutter is used which
includes two curtains of leading and trailing curtains and which
electrically runs the leading and trailing curtains to control the
shutter.
In this electric control type shutter, it is known that an abnormal
operation of the shutter is electrically detected and warning is given.
A typical shutter abnormality is "non-exposure", and this abnormality
indicates that a photograph is not exposed despite of a release operation
performed by a photographer.
There are roughly two causes for generation of the non-exposure. One is
that dust, and the like adhere to an attracting surface of a magnet
engaging the leading and trailing curtains and the magnet causes an
attraction defect. The other is that a driving mechanism of the shutter
curtain becomes defective or the shutter curtain per se is deformed and
the shutter curtain cannot run.
For a trouble of the non-exposure, the abnormality is not found until a
film is developed. This is a large trouble for the camera. Therefore, some
techniques of the warning of the abnormality at a photographing time have
been proposed.
For example, in U.S. Pat. No. 5,257,056, a leading curtain detection switch
and a trailing curtain detection switch are disposed, and a predetermined
warning is issued, when the abnormality of the curtain is detected
before/after driving the shutter. In U.S. Pat. No. 5,758,213, a reflective
optical sensor is disposed in a shutter portion, and this sensor detects a
run timing, exposure time or speed of the curtain and issues the warning.
The driving mechanism of the shutter varies also with a maker or a camera
type. Therefore, various "defects of the driving mechanism of the shutter
curtain" which are causes for the non-exposure are considered.
BRIEF SUMMARY OF THE INVENTION
According to a first aspect of the present invention, there is provided a
shutter abnormality detection apparatus for a camera comprising a shutter
including leading and trailing curtains which are shutter curtains
electrically controlled to run, the apparatus comprising:
a curtain run detection unit which detects a run state of at least one of
the leading and trailing curtains;
a curtain run time judgment unit which judges a run time of the shutter
curtains based on an output from the curtain run detection unit; and
an abnormality processing unit which notifies an abnormality state of the
shutter curtains, when it is judged as a result of judgment in the curtain
run time judgment unit that the curtain run time is abnormal.
Moreover, a second aspect of the present invention relates to the shutter
abnormality detection apparatus for the camera according to the first
aspect of the present invention, and the abnormality processing unit
includes an operation lock function which locks the subsequent operation
of the camera, when the curtain run time is judged to be abnormal.
Furthermore, a third aspect of the present invention relates to the shutter
abnormality detection apparatus for the camera according to the second
aspect of the present invention, and further comprises: a return unit
which returns the operation of the camera from the locked state in
response to a predetermined operation, when the subsequent operation of
the camera is locked by the abnormality processing unit; a curtain run
time recheck unit which again judges whether or not the run time of the
shutter curtain is normal during the operation of return by the return
unit; and a control unit which returns the operation of the camera to a
normal operation, when the run time of the shutter curtain is judged to be
normal as a result of judgment by the curtain run time recheck unit and
which controls and locks the subsequent operation of the camera, when the
run time of the shutter curtain is again judged to be abnormal.
Additionally, a fourth aspect of the present invention relates to the
shutter abnormality detection apparatus for the camera according to the
third aspect of the present invention, and the predetermined operation
includes an operation of a power switch or an attachment/detachment
operation of a power battery.
Moreover, a fifth aspect of the present invention relates to the shutter
abnormality detection apparatus for the camera according to the third
aspect of the present invention, and the curtain run time recheck unit
controls the operation so that the trailing curtain starts running ahead
of the leading curtain so as to prevent a useless exposure operation.
Furthermore, a sixth aspect of the present invention relates to the shutter
abnormality detection apparatus for the camera according to the first
aspect of the present invention. The curtain run time judgment unit
compares the run time of the shutter curtain detected by the curtain run
time judgment unit with a normal range value, and judges that the run of
the shutter curtain is abnormal, when the curtain run time is shorter or
longer than the normal range value.
Additionally, a seventh aspect of the present invention relates to the
shutter abnormality detection apparatus for the camera according to the
first aspect of the present invention. The shutter is brought into a
charge completion state, when the leading and trailing curtains of the
mechanically charged shutter are held by an electromagnet against an
urging spring, and the apparatus further comprises a control unit which
controls timings for releasing the holding of the leading and trailing
curtains by the electromagnet in the charge completion state and which
drives the leading and trailing curtains of the shutter by an action of
the urging force to allow an exposure operation.
Moreover, according to an eighth aspect of the present invention, there is
provided a shutter abnormality detection apparatus for a camera comprising
a shutter including leading and trailing curtains which are shutter
curtains electrically controlled to run, the apparatus comprising:
a leading curtain run detection unit which detects a run state of the
leading curtain of the shutter;
a trailing curtain run detection unit which detects the run state of the
trailing curtain of the shutter;
an exposure time determination unit which determines an appropriate
exposure time in accordance with an object situation;
a clocking unit which measures a time from the run completion of the
leading curtain detected by the leading curtain run detection unit until
the run completion of the trailing curtain detected by the trailing
curtain run detection unit; and
an abnormality processing unit which judges that the run of the shutter
curtain is abnormal and which notifies an abnormality state, when the time
measured by the clocking unit is not in a range of a calculated value
obtained by a predetermined calculation of the exposure time and a
predetermined time.
Moreover, a ninth aspect of the present invention relates to the shutter
abnormality detection apparatus for the camera according to the second
aspect of the present invention, and the predetermined time is a time in a
range of .+-.1 to .+-.3 msec.
Furthermore, a tenth aspect of the present invention relates to the shutter
abnormality detection apparatus for the camera according to the eighth
aspect of the present invention, and the predetermined time is a time
value of a fluctuation error allowed for a logically appropriate exposure
time.
Additionally, according to an eleventh aspect of the present invention,
there is provided a shutter abnormality detection apparatus for a camera
comprising a shutter including leading and trailing curtains which are
electrically controlled to run, the apparatus comprising:
a leading curtain run detection unit which detects completion of the run of
the leading curtain of the shutter;
a trailing curtain run detection unit which detects the completion of the
run of the trailing curtain of the shutter;
a measurement unit which measures beforehand a time difference between a
time required for the run of the leading curtain at a normal operation
time and a time required for the run of the trailing curtain;
a storage unit comprising a nonvolatile memory which stores the time
difference measured by the measurement unit as a correction value;
a clocking unit which measures a time from the run completion of the
leading curtain detected by the leading curtain run detection unit until
the run completion of the trailing curtain detected by the trailing
curtain run detection unit; and
an abnormality processing unit which judges that the run of either the
leading curtain or the trailing curtain is abnormal and which notifies an
abnormality state, when a time value measured by the clocking unit is not
in a range of a calculated value obtained by addition/subtraction of a
predetermined time with respect to a calculated value obtained by a
predetermined calculation of a time difference between a time of run start
of the leading curtain and a time of run start of the trailing curtain and
the correction value.
Moreover, according to a twelfth aspect of the present invention, there is
provided a shutter abnormality detection apparatus for a camera comprising
a shutter including leading and trailing curtains which are electrically
controlled to run, the apparatus comprising:
a leading curtain run detection unit which detects completion of the run of
the leading curtain of the shutter;
a trailing curtain run detection unit which detects the completion of the
run of the trailing curtain of the shutter;
a storage unit comprising a nonvolatile memory which stores a calculated
value of calculation based on a time required for the run of the leading
curtain at a normal operation time and a time required for the run of the
trailing curtain as a correction value;
a clocking unit which measures a time from the run completion of the
leading curtain detected by the leading curtain run detection unit until
the run completion of the trailing curtain detected by the trailing
curtain run detection unit; and
an abnormality processing unit which judges that the run of either the
leading curtain or the trailing curtain is abnormal and which notifies an
abnormality state, when a time value measured by the clocking unit is not
in a predetermined range of a calculated value obtained by a predetermined
calculation of a theoretical time from run start of the leading curtain
until the run start of the trailing curtain and the correction value.
Furthermore, according to a thirteenth aspect of the present invention,
there is provided a shutter abnormality detection apparatus for a camera
comprising a shutter including leading and trailing curtains which are
electrically controlled to run, the apparatus comprising:
a leading curtain run detection unit which outputs a run completion signal
of the leading curtain of the shutter;
a trailing curtain run detection unit which outputs the run completion
signal of the trailing curtain of the shutter; and
a shutter abnormality judgment unit which detects a state of the run
completion signal outputted from the other curtain run detection unit
based on the run completion signal from either one of the leading and
trailing curtain run detection units and which judges abnormality of the
shutter based on a detection result.
Additionally, a fourteenth aspect of the present invention relates to the
shutter abnormality detection apparatus for the camera according to the
thirteenth aspect of the present invention. The shutter abnormality
judgment unit judges that the shutter is abnormal, when the leading
curtain run detection unit outputs a run incompletion signal at an output
time of the run completion signal of the trailing curtain run detection
unit or when the trailing curtain run detection unit outputs the run
completion signal at the output time of the run completion signal of the
leading curtain run detection unit.
Moreover, a fifteenth aspect of the present invention relates to the
shutter abnormality detection apparatus for the camera according to the
thirteenth aspect of the present invention. The apparatus further
comprises: a shutter speed calculation unit which calculates an opening
time of the shutter based on an object luminance, and a prohibition unit
which prohibits an operation of the shutter abnormality judgment unit,
when the shutter speed is lower than a predetermined speed.
Furthermore, according to a sixteenth aspect of the present invention,
there is provided a shutter abnormality detection apparatus for a camera
comprising a shutter including leading and trailing curtains which are
shutter curtains electrically controlled to run, the apparatus comprising:
a first detection unit which detects a change of a level of a signal
indicating a run state of the leading curtain of the shutter;
a second detection unit which detects the change of the level of the signal
indicating the run state of the trailing curtain of the shutter; and
a shutter abnormality judgment unit which compares a detection timing of
the level change by the first detection unit with that of the level change
by the second detection unit and which judges that the run of the shutter
curtain is abnormal, when the detection timing of the level change by the
second detection unit is earlier than that of the level change by the
first detection unit.
Additionally, according to a seventeenth aspect of the present invention,
there is provided a shutter abnormality detection apparatus for a camera
comprising a shutter including leading and trailing curtains which are
shutter curtains electrically controlled to run, the apparatus comprising:
a strobe unit which irradiates an object;
a shutter abnormality judgment unit which judges whether or not the shutter
is abnormal based on a run state of the shutter curtain;
a flat light emitting unit which allows the strobe unit to emit light in a
flat state from start of an opening operation of the shutter until the
shutter is closed; and
a prohibition unit which prohibits the operation of the shutter abnormality
judgment unit, when the flat light emitting unit is controlled.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
The accompanying drawings, which are incorporated in and constitute a part
of the specification, illustrate presently preferred embodiments of the
invention, and together with the general description given above and the
detailed description of the preferred embodiments given below, serve to
explain the principles of the invention.
FIG. 1 is a block diagram schematically showing a shutter abnormality
detection apparatus for a camera according to a first embodiment of the
present invention;
FIG. 2 is a block diagram showing a constitution of the camera to which the
first embodiment of the present invention is applied;
FIG. 3 is a time chart showing an operation in a case in which a shutter 21
of FIG. 2 normally operates;
FIGS. 4A, 4B are schematic views showing states of an XSW 39, ACSW 40, and
shutter curtain 47 at a normal operation time;
FIGS. 5A, 5B are schematic views showing the states of the XSW 39, ACSW 40
and shutter curtain 47 at an abnormal operation time;
FIG. 6 is a time chart (low speed second time) showing an example in which
the shutter abnormally operates and showing an operation in a case in
which a leading curtain is charged but the trailing curtain is not
charged;
FIG. 7 is a time chart (high speed second time) showing an example in which
the shutter abnormally operates and showing an operation in the case in
which the leading curtain is charged but the trailing curtain is not
charged;
FIG. 8 is a time chart showing the example in which the shutter abnormally
operates and showing the operation in the case in which the trailing
curtain is charged but the leading curtain is not charged;
FIG. 9 is a time chart showing the operation in a case in which an
abnormality occurs in the speed of the shutter curtain (curtain speed)
under a normal shutter charge and the operation in a case in which the
speed of the trailing curtain is higher than that at a normal time (a
state in which a load on the trailing curtain is small);
FIG. 10 is a time chart showing the operation in a case in which the
abnormality occurs in the speed of the shutter curtain (curtain speed)
under the normal shutter charge and the operation in a case in which the
speed of the trailing curtain is lower than that at the normal time (a
state in which the load on the trailing curtain is large);
FIG. 11 is a flowchart showing an operation of the whole camera which is a
main control of a CPU 35;
FIG. 12 is a flowchart showing an operation of a sub-routine "exposure
operation" of step S7 in the flowchart of FIG. 11;
FIG. 13 is a flowchart showing an operation in a second example of the
sub-routine "exposure operation" of the step S7 in the flowchart of FIG.
11;
FIG. 14 is a flowchart showing an operation in a third example of the
sub-routine "exposure operation" of the step S7 in the flowchart of FIG.
11;
FIG. 15 is a flowchart showing an operation in the third example of the
sub-routine "exposure operation" of the step S7 in the flowchart of FIG.
11;
FIG. 16 is a flowchart showing an operation of a sub-routine "shutter
damage check" of step S14 in the flowchart of FIG. 11;
FIG. 17 is a time chart showing a modification example of an operation to
measure a trailing curtain run time;
FIG. 18 is a time chart showing the modification example of the operation
to measure a leading curtain run time;
FIG. 19 is a time chart showing the operation in a fourth example of the
sub-routine "exposure operation" of the step S7 in the flowchart of FIG.
11 according to the present invention;
FIG. 20 is a flowchart showing the operation in the fourth example of the
sub-routine "exposure operation" of the step S7 in the flowchart of FIG.
11;
FIG. 21 is a block diagram schematically showing the shutter abnormality
detection apparatus for the camera according to a second embodiment of the
present invention;
FIG. 22 is a time chart showing a state of each component at a time when
the abnormality is generated in the shutter;
FIG. 23 is a flowchart showing details of the step S7 (exposure operation)
of FIG. 11;
FIG. 24 is a flowchart showing details of a port interrupt process of an
XSW 39 permitted in step S224 of FIG. 23; and
FIG. 25 is a flowchart showing details of the port interrupt process of the
ACSW 40 permitted in the step S224 of FIG. 23.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
A first embodiment of the present invention will be described hereinafter
with reference to the drawings. FIG. 1 is a block diagram schematically
showing a shutter abnormality detection apparatus for a camera according
to the present invention.
In FIG. 1, a leading curtain run completion detection unit 1 is a unit for
detecting completion of run of a leading curtain of a focal plane shutter,
and a trailing curtain run completion detection unit 2 is a unit for
detecting the completion of the run of a trailing curtain of the focal
plane shutter. Detection outputs of the leading curtain run completion
detection unit 1 and trailing curtain run completion detection unit 2 are
supplied to a curtain run time judgment unit 3. Furthermore, the output of
the curtain run time judgment unit 3 is supplied to an abnormality
processing unit 4.
In this constitution, the leading curtain run completion detection unit 1
detects the completion of the run of the leading curtain of the focal
plane shutter of the camera. Similarly, the trailing curtain run
completion detection unit 2 detects the run completion of the trailing
curtain of the focal plane shutter.
Moreover, a run time of the curtain is detected in the curtain run time
judgment unit 3, based on a signal indicating the leading curtain run
completion of the shutter detected by the leading curtain run completion
detection unit 1 and a signal indicating the trailing curtain run
completion of the shutter detected by the trailing curtain run completion
detection unit 2. And it is judged in the curtain run time judgment unit 3
whether or not the curtain has normally run. Here, when it is judged that
the run of the curtain is abnormal, abnormalities such as operation lock
are processed in the abnormality processing unit 4.
FIG. 2 is a block diagram showing the constitution of the camera to which
the first embodiment of the present invention is applied.
In FIG. 2, a photography lens for forming an object image is constituted of
a positive lens 11 and negative lens 13 disposed via a diaphragm mechanism
12. That is, the diaphragm mechanism 12 is disposed in the photography
lens.
A movable mirror 14 whose middle portion substantially forms a half mirror
is disposed behind the negative lens 13. Moreover, an object light
reflected upwards by the movable mirror 14 reaches a finder eyepiece
optical system 17 via a focal plate 15 and penta prism 16.
In a middle rear surface portion of the movable mirror 14, a sub-mirror 18
is disposed so as to reflect the object light downwards. A separator
optical system 19 constituted of two optical systems to separate two
images is disposed in a vertical direction in the drawing which is a
reflective optical axis direction of the sub-mirror 18. A line sensor 20
is disposed in an image forming position of the object image by the
separator optical system 19.
Moreover, a shutter 21 and film 22 are disposed behind the movable mirror
14 as viewed from the photography lens. When the movable mirror 14 moves
upwards to bring the shutter 21 in an open state, the object image is
formed on the film 22 and exposed.
The shutter 21 is a known focal plane shutter, and generally mounted on the
camera which is a single lens reflex camera. For the focal plane shutter,
a built-in spring (not shown) is charged prior to the exposure, and the
leading and trailing curtains run by an urging force of the spring.
A zoom/focus driving circuit 25 for controlling a driving source for a
focus adjustment operation and zooming operation is disposed in each lens
11, 13 of the photography lens. A diaphragm driving circuit 26 is disposed
in the diaphragm mechanism 12. The zoom/focus driving circuit 25 includes
an encoder (not shown) which generates a signal in response to movement of
each lens described above. Moreover, the focus adjustment is carried out
by a CPU 35 described later based on the calculated driving amount and
encoder output.
Moreover, the movable mirror 14 is driven by a mirror driving circuit 27.
The line sensor 20 is similarly driven by a line sensor driving circuit
28, and the shutter 21 is driven by a shutter driving circuit 29.
The zoom/focus driving circuit 25, diaphragm driving circuit 26, mirror
driving circuit 27, line sensor driving circuit 28, and shutter driving
circuit 29 are connected to one another by a data bus 24. Furthermore, a
film driving circuit 30 for performing a winding operation of the film 22,
when the photography of one frame ends, a stroboscopic circuit 33, a
nonvolatile memory 34, the CPU 35, and a switch input circuit 36 are
connected to one another by the data bus 24 which transmits/receives
various data.
The sub-mirror 18, separator optical system 19, line sensor 20, and the
like constitute a focus detection apparatus by a known phase difference
method. Moreover, the CPU 35 obtains an interval between two images based
on the signal inputted via the line sensor driving circuit 28, and
calculates the driving amount of the photography lens to be driven in a
focused position.
It is to be noted that in the CPU 35, a diaphragm value and shutter speed
of the diaphragm mechanism 12 from which appropriate exposure is obtained
are calculated based on the object luminance outputted from a photometry
circuit (not shown) and film sensitivity detected by a film sensitivity
detection circuit (not shown). The shutter 21 is driven/controlled via the
shutter driving circuit 29 at a calculated shutter speed.
An exposure time for the film 22 is determined, when the leading curtain
engaged by a leading curtain magnet (not shown) and a trailing curtain
engaged by a trailing curtain magnet are opened at an appropriate timing
in accordance with the calculated shutter speed.
The stroboscopic circuit 33 is a circuit for object illumination, and
operates as an auxiliary light, when the CPU 35 judges that the object
luminance is lower than a predetermined luminance. The nonvolatile memory
34 is a memory for storing various adjustment data, operation state of the
camera, and the abnormal state of the shutter 21.
The switch input circuit 36 is constituted of a plurality of switches such
as an operation switch (not shown) and a detection switch of a mechanism
system operation. Here, detection switches according to the present
invention include: a mirror up switch (MUSW) 37 for detecting an operation
state of the movable mirror 14; a shutter charge switch (SCSW) 38 for
detecting a spring charge state of the shutter 21; a leading curtain
detection switch (XSW) 39 for detecting the operation state of the leading
curtain of the shutter 21; and a trailing curtain detection switch (ACSW)
40 for detecting the operation state of the trailing curtain of the
shutter 21.
The driving operation of the above-described zoom/focus driving circuit 25,
diaphragm driving circuit 26, mirror driving circuit 27, line sensor
driving circuit 28, shutter driving circuit 29, film driving circuit 30,
stroboscopic circuit 33, and nonvolatile memory 34 is generally controlled
by the CPU 35.
FIG. 3 is a time chart showing an operation in a case in which the shutter
21 normally operates. It is to be noted that the spring (not shown) built
in the shutter 21 is assumed to be already in the charged state.
First, a leading curtain magnet (Mg) for holding the leading curtain and a
trailing curtain magnet (Mg) for holding the trailing curtain are turned
on, and the diaphragm mechanism 12 is driven so as to move upwards the
movable mirror 14 and obtain the calculated diaphragm value. When the
operation of the movable mirror 14 is started, mechanical engagement of
the leading and trailing curtains is released. When the leading or
trailing curtain magnet is turned off, each curtain can run.
When the MUSW 37 for detecting the operation state of the movable mirror 14
changes to a "low level (L)" from a "high level (H)", the driving of the
mirror is completed. At this time, a photography luminous flux passed
through the positive lens 11, negative lens 13, and diaphragm mechanism 12
is incident upon the shutter 21, and the luminous flux into the finder
optical system is cur off.
Next, the leading curtain magnet is turned off to run the leading curtain,
and the exposure onto the film 22 is started. When the run of the leading
curtain is completed, the XSW 39 changes to on ("L") from off ("H").
Furthermore, the trailing curtain magnet is turned off to run the trailing
curtain, and the exposure onto the film 22 is cut off. When the run of the
trailing curtain is completed, the ACSW 40 changes to off ("H") from on
("L"). Moreover, in a predetermined time (a time sufficient for completing
the curtain run) after the trailing curtain magnet is off, the movable
mirror 14 is moved downwards, and the diaphragm mechanism 12 is driven in
a release position.
FIGS. 4A, 4B are schematic views showing the states of the XSW, ACSW, and
shutter curtain at a normal operation time. In FIGS. 4A and 4B, an
attracting member 44 is disposed in the vicinity of a shutter magnet 43,
which rotates upwards centering on a rotation center 44a in the charged
state and which is attracted by the magnet 43, when the shutter magnet 43
is turned on. This attracting member 44 is urged downwards by a spring
member 45. A switch member 46 is a switch electrically turned on, when the
attracting member 44 moves down by the urging of the spring member 45, and
is constituted of the above-described XSW 39 or ACSW 40. It is to be noted
that a reference numeral 47 denotes a shutter curtain (leading curtain or
trailing curtain).
First, a shutter charge time will be described.
As shown in FIG. 4A, the shutter is charged so that the shutter can run,
and the attracting member 44 rotates upwards centering on the rotation
center 44a. Then, the shutter curtain also moves upwards in the drawing by
an interlock mechanism (not shown) which interlocks with the rotation
movement of the attracting member 44. That is, the shutter magnet 43 is
turned on, the attracting member 44 is attracted, and the curtain is
brought into a state in which the running is possible.
Next, a shutter run completion time will be described.
The magnet 43 is turned off from the state shown in FIG. 4A. Then, as shown
in FIG. 4B, the attracting member 44 is rotated downwards centering on the
rotation center 44a by the urging force of the spring member 45, and the
shutter curtain 47 also runs downwards. When the attracting member 44
moves downwards, the switch member 46 interlocks and is electrically
turned on. That is, the XSW 39 or ACSW 40 is turned on. In this manner,
the XSW 39 or ACSW 40 interlocks with the movement of the shutter curtain
47 and attracting member 44, and is turned on.
FIGS. 5A, 5B are schematic views showing the states of the XSW 39, ACSW 40,
and shutter curtain 47 at an abnormal operation time.
When the operation is normal at a shutter charge time, as shown in FIG. 4A,
the shutter is charged so that the shutter can run. Then, the attracting
member 44 is rotated upwards centering on the rotation center 44a, and the
shutter curtain 47 should also move upwards by the interlock mechanism
(not shown) which interlocks with the movement of the attracting member
44. However, some abnormalities (adhesion of dust, component defects, and
the like) are generated in the interlock mechanism, and the shutter
curtain 47 interlocks and does not move upwards. This state is shown in
FIG. 5A. That is, the shutter is not exactly charged in the state. Even in
this state, only the attracting member 44 moves upwards and is charged.
FIG. 5B is a schematic diagram of a shutter run completion time in the
abnormal operation.
When the magnet 43 is turned off from the state of FIG. 5A, the attracting
member 44 is rotated downwards centering on the rotation center 44a by the
urging force of the spring member 45, and the XSW 39 or ACSW 40 is turned
on in the same manner as in the state shown in FIG. 4B. However, since the
shutter curtain 47 is originally uncharged and positioned downwards, the
shutter curtain 47 is not driven at all.
That is, the XSW 39 or ACSW 40 is turned on, and it seems as if the run of
the shutter curtain 47 was completed. In actual, however, the shutter
curtain 47 is not driven from the beginning, and non-exposure occurs. In
the shutter including a mechanism in which the shutter curtain 47
interlocks with the attracting member 44 by the interlock mechanism, such
unexposed state possibly occurs.
Next, an example in which the shutter abnormally operates will be described
with reference to time charts of FIGS. 6 to 10. It is to be noted that the
operation at the normal time has been described with reference to the time
chart of FIG. 3, and therefore only a portion changed from that at the
normal time will be described.
FIG. 6 is a time chart (low speed second time) showing the operation in a
case in which the leading curtain is charged but the trailing curtain is
not charged.
In FIG. 6, the leading curtain interlocks with the off state of the leading
curtain magnet and starts running. When the run is completed, the XSW 39
is turned on. However, the trailing curtain is not charged by
disadvantages described with reference to FIGS. 5A, 5B. Even when the
trailing curtain magnet is turned off, the curtain does not run at all. As
described with reference to FIGS. 5A, 5B, the ACSW 40 is turned on even at
this abnormal time, and a signal indicating as if the shutter curtain run
were completed is outputted.
However, for the attracting member 44, since the shutter curtain 47 is not
involved as the load, the load of the spring member 45 is smaller than
that at the normal time. Therefore, the urging force becomes relatively
strong, and the switch member 46 is turned on earlier than the normal time
by the attracting member 44. That is, a time (t.sub.TRAIL) from when the
trailing curtain magnet is off until the ACSW 40 is on indicates a value
smaller than that at the normal time.
Moreover, although not shown, the attracting member 44 is driven with a
small load. Therefore, the attracting member 44 strikes the ACSW 40 with a
force stronger than that at the normal time. Chattering at a time when the
ACSW 40 is turned on is sometimes observed to be large.
FIG. 7 is a time chart (high speed second time) showing the operation in
the case in which the leading curtain is charged but the trailing curtain
is not charged.
The above-described time chart of FIG. 6 relates to the low speed second
time, and the XSW 39 is turned on before the ACSW 40. However, at the high
speed second time, a shutter opening time shortens, and a state could
arise in which the ACSW 40 is turned on before the XSW 39.
Even in this case, a value of the time t.sub.TRAIL is the same as that of
t.sub.TRAIL shown in the time chart of FIG. 6. Therefore, even when a
timing for turning on the XSW 39 or ACSW 40 shifts forwards/backwards,
abnormality detection is possible.
FIG. 8 is a time chart showing the operation in the case in which the
trailing curtain is charged but the leading curtain is not charged.
In FIG. 8, the trailing curtain interlocks with the off state of the
trailing curtain magnet and starts running. When the run is completed, the
ACSW 40 is turned on. However, the leading curtain is not charged by the
disadvantages described with reference to FIGS. 5A, 5B. Even when the
leading curtain magnet is turned off, the curtain does not run at all. As
described with reference to FIGS. 5A, 5B, the XSW 39 is turned on even at
this abnormal time, and the signal indicating as if the shutter curtain
run were completed is outputted.
However, for the attracting member 44, since the shutter curtain 47 is not
involved as the load, the load of the spring member 45 is smaller than
that at the normal time. Therefore, the urging force becomes relatively
strong, and the switch member 46 is turned on earlier than the normal time
by the attracting member 44. That is, a time (t.sub.LEAD in the drawing)
from when the leading curtain magnet is off until the XSW 39 is on
indicates a value smaller than that at the normal time. The chattering
possibly occurs in the same manner as in the trailing curtain abnormality
time.
FIGS. 9 and 10 are time charts of a case in which the shutter is normally
charged but speed (curtain speed) abnormality of the shutter curtain
occurs.
With reference to FIGS. 6 to 8, the time charts have been described in
which the shutter curtain does not run because of charge defect but the
run completion switch turns on in the shutter of such a type that the
shutter curtain 47 and attracting member 44 move in separate mechanisms.
Here, in the shutter of such a type that the shutter curtain 47 moves
integrally with the attracting member 44, even when the curtain is
normally charged but there is some trouble in an urging mechanism (not
shown) for running the shutter curtain and the curtain does not run at a
correct curtain speed, the detection is possible. This time chart of the
present invention will be described.
FIG. 9 is a time chart showing the operation in a case in which the speed
of the trailing curtain is higher than that at the normal time (a state in
which a load on the trailing curtain is lightened).
In this case, since the trailing curtain is driven faster than the normal
time, the time t.sub.TRAIL is shorter than that at the normal time. In
FIG. 9, the trailing curtain gets ahead of the leading curtain, but this
differs by second time. In the present invention, since the time
t.sub.TRAIL is measured, the detection is possible even in this case.
FIG. 10 is a time chart showing the operation in a case in which the speed
of the trailing curtain is lower than that at the normal time (a state in
which the load on the trailing curtain is increased).
In this case, since the trailing curtain is driven later than the normal
time, the time t.sub.TRAIL is longer than that at the normal time. In the
present invention, since the time t.sub.TRAIL is measured, the detection
is possible even in this case.
It is to be noted that the above-described time charts of FIGS. 9 and 10
show the trailing curtain, but the detection can similarly be performed
even with the leading curtain.
Next, an operation of the whole camera will be described with reference to
flowcharts of FIGS. 11 to 13.
FIG. 11 is a flowchart showing the operation of the whole camera which is a
main control of the CPU 35.
In a normal end state in which the previous damage does not end, a main
switch (not shown) is turned on, and then first in step S1, each component
of a camera main body is initialized, and is ready for photography on
standby. Next in step S2, it is judged whether or not a first release
switch (not shown) has been turned on. Here, the release switch of the
camera according to the present invention is constituted of a general
two-stages switch. When the first release switch in a half pressed state
is turned on, photometry or distance measuring is carried out. When a
second release switch in a totally pressed state is turned on, the
exposure is realized.
When the first release switch is not turned on in the step S2, the process
shifts to step S10. When the first release switch is turned on, the
process shifts to step S3.
In the step S3, the photometry is carried out by a photometry sensor (not
shown), and a diaphragm value shutter speed value is calculated. Next in
step S4, focus adjustment is carried out in step S4. Subsequently, as a
result of the step S4, it is judged in step S5 whether or not the
photography lens is in a focused state. Here, when the state is not the
focused state, the process shifts to step S9. In the focused state, the
process shifts to step S6.
It is judged in the step S6 whether or not the second release switch is
turned on. Here, when the switch is not turned on, the process shifts to
step S9. On the other hand, when the second release switch is turned on,
the process shifts to step S7 to carry out a shutter control and exposure
(exposure operation) of a film. This film exposure will be described later
in detail.
After the film is exposed, one frame of film is wound up in step S8.
Subsequently, in step S9, display of the number of frames in a display
portion (LCD) (not shown) is changed. Thereafter, the process shifts to
the step S2.
Moreover, when the first release switch is off in the step S9, the process
shifts to step S10, and it is judged whether or not states of other
switches (not shown) (photography mode switch, strobe switch, zoom switch,
and the like) are changed. Here, when the states of the other switches are
unchanged, the process shifts to step S9. On the other hand, when the
states are changed, the process shifts to step S11, and processing for the
changed switch is carried out. Thereafter, the process shifts to the step
S9. The operation at the normal time has been described above.
On the other hand, when the damage is generated last time and the operation
ends in the locked state, again the operation of the camera is resumed by
the operation of the main switch (not shown) or the detaching/inserting of
the battery. The operation in this case (steps S12 to S14) will be
described.
To return from the damage, the process is resumed from step S12. In the
step S12, it is judged whether or not a permanent lock state is achieved.
This "permanent lock state" indicates that when critical troubles such as
non-exposure are generated, the locked state is permanently continued so
that the photography is impossible as long as the camera is not brought
into repair. When the camera is brought into this state, a predetermined
damage flag is written in the nonvolatile memory 34 at a damage generation
time.
It is to be noted that in an embodiment described later, an example in
which the camera is not brought into the permanent lock state has been
described. To bring the camera into the permanent lock state, concretely,
at the same time a shutter damage flag is set, a predetermined permanent
lock flag is also set, and may be written in the nonvolatile memory 34.
When the camera is not in the permanent lock state in the step S12, the
process shifts to step S13, and each component is initialized in the same
manner as in the step S1. Next, in step S14, the component ended in the
damaged state is rechecked. For example, when the operation ends in a
shutter damaged state, a shutter damage is checked. Thereafter, the
process shifts to the step S2.
On the other hand, when the permanent lock state is judged in the step S12,
a damage lock process is carried out.
FIG. 12 is a flowchart showing an operation of a sub-routine "exposure
operation" of the step S7 in the flowchart of FIG. 11. The flowchart of
FIG. 11 corresponds to the time charts of FIGS. 6, 7, 9, and 10, and the
run time of the trailing curtain is measured.
First in step S21, the leading and trailing curtain magnets are turned on,
and the leading and trailing curtains are engaged. That is, a shutter
charge completed, run preparation completed state is achieved.
Subsequently, in step S22, upward driving of the movable mirror 14 and
close-driving of the diaphragm mechanism 12 to a set position are carried
out. Subsequently, the steps S22 and S23 are repeated until a mirror up
completion signal ("L" of the MUSW 37) is observed in step S23.
It is to be noted that here, to cancel the chattering of the MUSW 37, logic
of the MUSW 37 is read a plurality of times at a predetermined time (about
100 .mu.s) interval. When the logic is the same a plurality of times, this
logic is decided. This method may be used (not shown in the drawing).
Next in step S24, the leading curtain magnet is turned off to start running
the leading curtain. Subsequently, in step S25, the process is on standby
for a time (exposure time) corresponding to a shutter speed calculated in
the step S3 in the flowchart of FIG. 11.
When this exposure time elapses, the process shifts to step S26, and the
trailing curtain magnet is turned off to start running the trailing
curtain. Additionally, in order to measure the run time of the trailing
curtain, a timer is started in step S27.
In step S28, the process is on standby until the ACSW 40 is turned on
("L"). Here, to cancel the chattering of the ACSW 40, the logic of the
ACSW 40 is read a plurality of times at the predetermined time (about 100
.mu.s) interval. When the logic is the same a plurality of times, this
logic is decided. This method may be used (not shown in the drawing).
When the ACSW 40 is on in the step S28, the process shifts to step S29, and
the trailing curtain run time t.sub.TRAIL is read from a trailing curtain
run time measurement timer. Subsequently, it is judged in step S30 whether
or not the trailing curtain run time t.sub.TRAIL is in a predetermined
range (t.sub.1 <t.sub.TRAIL <t.sub.2) This predetermined range is a
time range of a value determined by the designing or manufacturing of the
shutter, and any normal product falls within this range.
When the trailing curtain run time t.sub.TRAIL falls in the predetermined
range, the state is normal, and the process shifts to step S31. Moreover,
in this step S31, as described with reference to the time chart of FIG. 3,
the process is on standby from when the trailing curtain magnet is off
until the predetermined time elapses. For this predetermined time, the
trailing curtain run time timer may be used, or a separate timer may also
be used, and the time is sufficient for the trailing curtain to end the
run.
When the predetermined time elapses, the process shifts to step S32 to
carry out down driving of the movable mirror 14 and driving of the
diaphragm mechanism 12 to a fully open position. Thereafter, the process
shifts to the step S8 of the flowchart of FIG. 11 through this routine.
On the other hand, in the step S30, when the trailing curtain run time
t.sub.TRAIL is not in the predetermined range, there is a possibility that
the non-exposure arises. Therefore, the process shifts to step S33 to set
a shutter damage flag. This flag is written in the nonvolatile memory 34.
Although not shown, to achieve the permanent lock state described in the
step S12 of the flowchart of FIG. 11, here a predetermined permanent lock
flag may be set and written into the nonvolatile memory 34.
Subsequently, in step S34, the down driving of the movable mirror 14 and
driving of the diaphragm mechanism 12 to a fully open position are carried
out. Subsequently, after the shutter is charged in step S35, a damage lock
process is carried out. This damage lock process is a process in which the
operation of the camera is locked and the subsequent operation is
prohibited. To escape from this lock state, the process is restarted by
the operation of the main switch (not shown) and the inserting/detaching
of the battery, and a process operation is restarted from the step S12 of
the flowchart of FIG. 11.
FIG. 13 is a flowchart showing an operation in a second example of the
sub-routine "exposure operation" of the step S7 in the flowchart of FIG.
11. This flowchart of FIG. 11 corresponds to the time chart of FIG. 8, and
the run time of the leading curtain is measured.
Since the process operation of steps S41 to S44 is the same as that of the
steps S21 to S24 in the flowchart of FIG. 12, the description is omitted.
Next, at the same time the leading curtain magnet is turned off in the
step S44, in step S45 a timer for measuring the run time of the leading
curtain is started.
Subsequently, it is judged in step S46 whether or not the leading curtain
run time t.sub.LEAD has been calculated. Here, when the time is
calculated, the process shifts to step S49. When the time is not
calculated, the process shifts to step S47, and is on standby until the
XSW 39 is turned on ("L"). Here, to cancel the chattering of the XSW 39,
the logic of the XSW 39 is read a plurality of times at the predetermined
time (about 100 .mu.s) interval. When the logic is the same a plurality of
times, this logic is decided. This method may be used (not shown in the
drawing).
When the XSW 39 is off in the step S47, the process shifts to step S49. On
the other hand, when the XSW 39 is on, the process shifts to step S48, and
the leading curtain run time t.sub.LEAD is read from a leading curtain run
time measurement timer.
In step S49, the process is on standby only for a time (exposure time)
corresponding to the shutter speed calculated in the step S3 of the
flowchart of FIG. 11. Here, the steps S46 to S49 are repeated until the
exposure time elapses. When the exposure time elapses, the process shifts
to step S50, and the trailing curtain magnet is turned off to start the
run of the trailing curtain.
Next, it is judged again in step S51 whether or not the leading curtain run
time t.sub.LEAD has been calculated. Some exposure time is not calculated
in the step S48. In this case, the process shifts to step S52.
In the step S52, the process is on standby until the XSW 39 is turned on
("L"). Here, the process is on standby until the XSW 39 is on.
Subsequently, when the XSW 39 is on, the process shifts to step S53 to
calculate the leading curtain run time t.sub.LEAD from the leading curtain
run time measurement timer.
It is judged in step S54 whether or not the leading curtain run time
t.sub.LEAD is in a predetermined range (t.sub.1 <t.sub.LEAD
<t.sub.2). This predetermined range is a time range of the value
determined by the designing or manufacturing of the shutter, and any
normal product falls within this range. Basically, the predetermined
ranges of the leading and trailing curtains are the same.
When the leading curtain run time t.sub.LEAD falls in the predetermined
range, the process shifts to step S55. When the time is not in the
predetermined range, the process shifts to step S57.
Since the process operations of steps S55 and S56, S57 to S59 are the same
as those of the steps S31 and S32, S33 to S35 in the flowchart of FIG. 12,
the description is omitted.
FIGS. 14 and 15 are flowcharts showing the operation in a third example of
the sub-routine "exposure operation" of the step S7 in the flowchart of
FIG. 11. For this third operation example, the above-described first and
second examples are combined to form an example in which both the leading
and trailing curtain run times are measured.
Since the process operation of steps S61 to S70 is the same as that of the
steps S41 to S50 in the flowchart of FIG. 13, the description is omitted.
In step S71, a timer is started to measure the run time of the trailing
curtain. Subsequently, it is judged in step S72 whether or not the leading
curtain run time t.sub.LEAD has been calculated in the step S68 or in step
S75 described later and whether or not the trailing curtain run time
t.sub.TRAIL has been calculated. When the run times are not calculated in
this step S72, the process shifts to step S73. When the run times are
calculated, the process shifts to step S79.
It is judged in step S73 whether or not the leading curtain run time
t.sub.LEAD has been calculated. Here, when the
