JP2001042382A - Exposure adjusting device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an exposure adjusting device capable of detecting the abnormal exposure without addition of new components. SOLUTION: Four shutter blades 1 constituted of two pairs of internal and external blades having different rotating directions are arranged so that the rotational center of a pair may be different from that of the other, and a slit is formed at each leading end part of one of the internal and external blades. In an initial state where the shutter blades are closed, sensor light between the light projection/reception parts of a conventionally arranged photoreflector 9 is shielded by the leading end parts of the shutter blades, and the sensor light from the photoreflector 9 is made to pass through the slit instantaneously on this side of a position where a photographing luminous flux starts passing in accordance with the opening movement of the shutter blades when a PR signal is at a high level so as to change the level of the PR signal, and prior to the exposure, the abnormal exposure is detected on the basis of the presence or absence of the level change.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure control device for a camera, and more particularly, to an exposure control device for a camera that detects an exposure abnormality caused by shutter blades that block or pass a photographic light beam.

[0002]

2. Description of the Related Art In general, a camera has a photographing optical system for forming a light image in order to expose a film to a light image, an aperture mechanism for controlling the amount of a photographing light beam from the photographing optical system, and opening and closing of shutter blades. Is provided.

[0003] An exposure device that blocks and passes a photographing light beam by opening and closing a plurality of shutter blades that can freely open and close, and when an abnormality occurs in exposure, detects that the exposure has occurred, and informs the user. There are cameras that can be recognized.
As one example, for example, Japanese Patent Application Laid-Open No. 10-78600 proposed by the present applicant discloses three inner blades for shielding a photographing light beam near an optical axis and three outer blades for shielding a photographing light beam in a peripheral portion. A shutter wheel composed of: a shutter wheel that drives these shutter blades; and opening of the exposure opening by detecting the rotation state of the wheel, the minimum predetermined opening amount required for exposure, and the closing of the exposure opening. And a drive control circuit that determines whether or not there is an exposure abnormality based on the output of the photointerrupter.If there is an exposure abnormality, the user is notified of the abnormality by sound or display. An exposure adjusting device for a camera having a warning unit for notifying is described.

[0004]

However, Japanese Patent Application Laid-Open No.
The exposure adjusting device described in Japanese Patent Application Publication No. 0-78600 is an exposure adjusting mechanism using six shutter blades and a shutter blade driving member (arrow wheel), and its configuration is complicated. Also,
In a two-blade, four-blade type exposure adjusting device, a shutter blade position detecting member for detecting an exposure abnormality or a determining member for determining whether or not exposure due to opening and closing operations of the shutter blade is abnormal. Etc. are not provided. These two blades and four blades (A, B, C,
In the case of the D) type exposure controller, the presence or absence of the tip is detected as a signal generating member for starting the exposure adjustment near the tip of one of the two (four) blades. It is conceivable to arrange a photointerrupter (photoreflector) to be used.

However, the signal obtained from the photointerrupter is a trigger signal for starting the adjustment of the exposure amount, and the trigger signal determines whether the exposure by the opening / closing operation of the shutter blade has been performed reliably or not. It cannot be determined. On the other hand, adding another position detection member for detecting this abnormality not only complicates the configuration, but also leads to an increase in the size of the exposure adjusting device.

Furthermore, without increasing the number of position detecting members,
A method for generating a trigger signal for starting the exposure adjustment and a signal necessary for determining whether or not the exposure due to the opening / closing operation of the shutter blade is abnormal. This is made possible by extending the section. That is, by moving the position detecting member closer to the opening or extending the tip of the shutter blade,
The determination is made by delaying the generation timing of the trigger signal for starting the exposure adjustment. Therefore, the position detection member may be brought closer to the opening or the tip of the shutter blade may be extended to a position where the trigger signal is generated at a timing at which it can be determined whether or not exposure due to the opening / closing operation of the shutter blade is abnormal.

In addition, at the timing when a trigger signal for starting the exposure adjustment has been generated conventionally, the signal is generated by moving the position detecting member closer to the opening or extending the tip of the shutter blade. In this case, a signal (edge) detected by the position detecting member is provided by providing a slit or a notch at the tip of the shutter blade used for generating the trigger signal for starting the exposure adjustment among the shutter blades. May be increased, and the increased signal may be used as a trigger signal for starting the exposure adjustment.

However, when the position detecting member is moved closer to the opening, the shutter blade for blocking the photographing light beam enters a place to be retracted in the open state, and the size of one shutter blade decreases. As a result, the amount of overlap between the shutter blades is reduced.

In the initial closed state, if the amount of overlap of the shutter blades is less than a predetermined amount, the opening cannot be completely shielded from light, and it is structurally difficult to provide the position detecting member close to the opening.

When the tip of the shutter blade is extended, if the size is not restricted, the shutter blade C which extracts a trigger signal for starting the exposure amount adjustment is obtained.
It is possible to further extract a signal necessary for determining whether or not exposure due to the opening and closing operation of the shutter blade is abnormal without adding a new position detecting member by extending the leading end portion of the slit. . However, in the structure of the conventional exposure adjusting device, there is a shutter blade whose tip portion is further extended, and the enlargement of the exposure adjusting device is inevitable.

Therefore, in the initial closed state, when the leading end of the shutter blade D that shields the peripheral portion of the photographing light beam is extended and provided with a slit, the shutter blade C that shields the central portion of the photographing light beam is lower than the shutter blade C that shields the central portion of the photographing light beam. Since the rotation angle driven by the lever serving as the blade driving member is small, it is possible to avoid an increase in the size of the exposure adjusting device by extending the tip of the shutter blade C and providing a slit.

However, the shutter blade C which has conventionally been used to extract a trigger signal for starting the exposure amount adjustment is used.
Must be shorter than before in order to avoid a slit provided in the shutter blade D at a predetermined position.
When the leading end of the shutter blade C is shortened, the central portion of the photographing light beam is shielded in the initial closed state, and the shutter blade B having a different rotation direction and overlapping with each other does not have a predetermined amount of overlap in the open state. It becomes possible.

If the shutter blades do not have a predetermined amount of overlap in the open state of the shutter blades, and the shutter blades B and C are driven from the open state to the closed state, the leading ends of the shutter blades B and C will not move. May be replaced, and the function as an exposure control device may be impaired.

Therefore, the trigger signal for starting the exposure adjustment without shortening the tip of the shutter blade C and without increasing the size of the exposure adjusting device and whether or not the exposure due to the opening / closing operation of the shutter blade C is abnormal. In order to generate a signal required for the determination, a slit or a notch may be provided in the shutter blade C so that the slit provided in the shutter blade D can be avoided at a predetermined position.

However, among the shutter blades C and D, the one for taking out a trigger signal for starting the adjustment of the exposure amount is to perform exposure control with higher precision if it is taken by the shutter blade which determines the exposure amount of the photographing light beam. Can be.

Accordingly, each of the shutter blades C and D has a slit at the tip thereof, and each of the shutter blades C and D has a slit so that a trigger signal for starting the exposure adjustment generated when the shutter blade is moved by a predetermined amount can be extracted by the shutter blade C. It is good to give the slit position and size.

Accordingly, the present invention provides an exposure adjusting device for a camera which can prevent an increase in size without adding a new position detecting member or the like, and can detect when an abnormality occurs in exposure. Aim.

[0018]

In order to achieve the above-mentioned object, an exposure adjusting device for a camera according to the present invention is opened and closed by being rotated around a predetermined axis, respectively. In an exposure control device for a camera having a plurality of shutter blades that shields a photographing light beam passing through the system and retreats from a passage of the photographing light beam when in an open state, the shutter blades of the photographing light beam are initially closed. The shutter blades B and C, which have a central portion shielded from each other, rotate in different directions, overlap each other, and have a predetermined amount of overlap even in the open state, and shield the peripheral portion of the photographic light beam in the initial closed state, and rotate in different directions. Shutter blades B and C
The shutter blades A and D overlap each other so as to sandwich them. The shutter blades C and D that rotate in the same direction have slits or cutouts at their leading ends, and the leading ends of the shutter blades C and D in the initial closed state. A position detecting means for generating a signal when the shutter blade has moved by a predetermined amount; detecting the presence or absence of an output signal from the position detecting means; A determining means for determining that the exposure due to the opening / closing operation of the shutter blades A, B, C, D is abnormal.

Each of the shutter blades C and D is rotated about a predetermined axis, and has a slit at a tip end thereof.
Alternatively, a second binary state is generated.

In the initial state where the shutter blade is closed, a first signal is generated. When the shutter blade moves in the opening direction, the shutter blade is closed by a predetermined amount before the position where the photographing light beam starts to pass. The signal changes from the first signal to the second signal at the position, and when the shutter blade moves in the opening direction, the second signal is at the closed position that is a predetermined distance before the position where the photographing light beam starts to pass. The signal changes from the signal to the first signal, and the second signal can be generated at a position shifted by a predetermined amount to the opening side from the position where the photographing light beam starts to pass next.

Further, a determination means for detecting the presence / absence of the above-mentioned signal and judging that the exposure due to the opening / closing operation of the shutter blades is abnormal when there is no signal generation is provided. In such a case, it is possible to provide an exposure control device for a camera that can detect that fact.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic exploded perspective view showing an embodiment of a camera exposure adjusting device according to the present invention as viewed from the front side, and will be described. FIG. 2 is a diagram showing a detailed configuration of the plunger shown in FIG.

This exposure control device comprises two outer blades 1a,
1d and a shutter blade 1 including two inner blades 1b and 1c, and a housing 2 supporting these shutter blades 1
A lever 3 serving as a blade driving member for rotating the shutter blade 1, a lever spring 4 for urging the lever 3 in the shutter blade opening direction to generate a driving force, a solenoid 5, an iron core 6, and a closing spring. 7, a photoreflector 9 and a reflection member 10 for detecting the position of the shutter blade 1, and energization to the solenoid 5 to determine an exposure abnormality by opening and closing the shutter blade 1. A drive control circuit 11 having a determination function, a photometric unit 12 for measuring the luminance of a subject (not shown), a film sensitivity detecting unit 13 for detecting film sensitivity, a release unit 14 for taking in exposure start instruction information, a display and sound And a warning unit 15 for giving various warnings to the photographer.

The plunger 8 urges the lever 3 in the closing direction of the shutter blade 1 when no power is supplied to the solenoid 5, and attracts the iron core 6 when power is supplied. In addition, slits for securing the optical paths of the photoreflector 9 and the reflecting member 10 are provided at the leading ends of the shutter blades 1c and 1d, respectively. Note that a photo interrupter may be used instead of the photo reflector 9 and the reflection member 10 used for detecting the position of the shutter blade 1.

Next, FIGS. 3 to 6 show a series of state changes from the closing to the opening of the shutter blade 1, and the operation of the exposure adjusting apparatus of the present embodiment will be described. FIGS. 7A and 7B show states 1 in the exposure control device at (a) low luminance and (b) high luminance.
FIG. 10 is a diagram showing a timing chart of the opening / closing operation of the shutter blades including from state 4 to state 4;

FIG. 3 is a view showing an initial closed state (state 1) of the exposure adjusting device. This state 1 is a state in which the shutter blades 1 overlap each other so as to block the photographing light beam from the photographing optical system before the release operation. At this time, the tips of the shutter blades 1c and 1d enter between the photoreflector 9 and the reflection member 10 attached to the housing 2 so as to connect the light projecting portion 9a and the light receiving portion 9b of the photoreflector, respectively. The light is shielded (arrows A... H level [first signal] in FIG. 7A).

FIG. 4 shows a state (state 2) in which when the solenoid 5 is energized, the iron core 6 is attracted, the lever 3 is driven, and the shutter blades 1a, 1b, 1c, 1d move in the opening direction. ing. (Arrow B... L level [second signal] in FIG. 7 (a)) This state 2 is a closed position that is a predetermined distance before the position where the photographing light beam starts to pass, and is still in a light-shielded state. . Slits provided at the respective leading end portions of the shutter blades 1c and 1d move to approximately the center of the light projecting portion 9a and the light receiving portion 9b of the photo reflector 9, and overlap. By this movement, the photoreflector 9 secures an optical path, receives the sensor light from the light projecting unit 9a via the reflecting member 10 and the light receiving unit 9b, and changes the PR signal from H level to L level.
Change to a level. The change to the L level is used as a trigger for starting the exposure adjustment, and the exposure adjustment time from when the trigger is generated is counted. When the exposure adjustment time based on the photometric value of the subject or the like has elapsed, the power to the solenoid 5 is stopped, and the shutter blade 1 is turned off.
Close.

If the subject brightness is equivalent to the high brightness limit determined by the specifications of the camera, as shown in FIG. 7B, after the exposure adjustment time equivalent to the high brightness elapses, The power supply to the solenoid 5 is stopped.

Then, from the state 2 shown in FIG. 4, when the shutter blades 1a, 1b, 1c and 1d are driven by the lever 3 and further moved in the opening direction, the shutter blades 1a, 1b, 1c and 1d are moved forward by a predetermined amount from the position where the photographing light beam starts to pass. And the slits provided at the tips of the shutter blades 1c and 1d are the light projecting portion 9a and the light receiving portion 9b of the photo reflector 9.
, The sensor light is blocked, and the PR signal changes from L level to H level.
(It is an arrow B '... H level in FIG. 7A and is between the state 2 and the state 3 shown in FIG. 5).

FIG. 5 shows the shutter blades 1a, 1b, 1c,
1d is driven by the lever 3 and further moved in the opening direction (state 3).

This state 3 is a state in which the photographing light beam has moved to the opening side by a predetermined amount from the position where the photographic light beam starts to pass between the shutter blades 1, and the leading end of the shutter blade 1 d has the light projecting portion 9 a of the photo reflector 9. Pass through substantially the center of the light receiving section 9b. At this time, the tip of the shutter blade 1c has already passed substantially the center between the light projecting portion 9a and the light receiving portion 9b of the photo reflector 9.

At the point when the tip of the shutter blade 1d has passed substantially the center between the light projecting portion 9a and the light receiving portion 9b, the photoreflector 9 is in a state where light is not shielded (state 3), as shown in FIG. At the arrow C, the PR signal changes from the H level to the L level. By detecting the L-level PR signal, it is determined whether or not the exposure due to the opening / closing operation of the shutter blade 1 is abnormal. If the PR signal does not change to the L level, it can be assumed that the shutter blade 1 has not opened, that is, it has not been exposed to the film, and it is determined that an abnormality has occurred.

FIG. 6 shows the shutter blades 1a, 1b, 1c,
1d shows a fully opened state (state 4). In the above-described initial closed state, the shutter blade 1 shields the central portion of the photographing light beam, and has different rotation directions and overlaps each other.
b and 1c are the shutter blades 1b and 1c even in state 4.
Have a predetermined amount of overlap at the tip portions. Therefore, in the shutter blades 1b and 1c, the tip portions of the shutter blades 1b and 1c do not change during a series of operations for adjusting the exposure amount.

As described above, according to the embodiment, four inner blades and two outer blades having different rotation directions are used.
The shutter blades are arranged at positions where the center points of rotation are different from each other, and slits are provided at respective ends of one of the inner spring and the outer blade. In the initial state where the shutter blades are closed, the light
The sensor light between the light receiving units is shielded at the tip of the shutter blade, and the PR signal is at the H level. As the shutter blade moves in the opening direction, the sensor light of the photoreceptor is passed and shielded, Generate a change in signal level. By this level change, not only a trigger signal for adjusting the exposure amount can be obtained, but also an abnormality in the exposure can be detected. Therefore, the present invention can be realized only by providing a slit on the shutter blade without additionally mounting a new position detecting member for detecting an exposure abnormality.

Although the above embodiments have been described, the present invention includes the following inventions. (1) Each of them is opened and closed by being rotated about a predetermined axis, and when in a closed state, blocks a photographing light beam passing through a photographing optical system, and when in an open state, retreats from a passage of the photographing light beam. In a camera exposure control apparatus having a plurality of shutter blades, the shutter blades shield a central portion of a photographic light beam in an initial closed state, rotate in different directions, overlap with each other, and a predetermined amount even in an open state. The first and second shutter blades overlap each other so as to intercept the peripheral portions of the photographic light beam in the initial closed state, rotate in different directions, and sandwich the second and third shutter blades. And fourth shutter blades, the opening holes being provided in the vicinity of the tips of the third and fourth shutter blades rotating in the same direction, and in the initial closed state, Is 3 and disposed opposite to the front end portion of the fourth shutter blade, and a position detecting means for third and fourth shutter blade generates a signal when moved by a predetermined amount,
The presence / absence of an output signal from the position detecting means is detected, and if no predetermined signal is generated, the first, second, third and fourth signals are output.
A determining means for determining that there is an abnormality in the exposure due to the opening / closing operation of the shutter blades.

(2) In the above item (1), the position detecting means generates a first or second binary state signal in accordance with a moving position of the third and fourth shutter blades, and In the initial state where the blade is closed, the first signal is generated, and when the shutter blade moves in the opening direction from the closed state to the open state, a predetermined amount is located before the position where the photographing light beam starts to pass. Is changed from the first signal to the second signal at the closed position, and when the shutter blade subsequently moves in the opening direction, by a predetermined amount from the position at which the photographing light beam starts to pass. The second signal changes from the second signal to the first signal at the front closed position, and then the second signal is generated at a position further moved in the opening direction by a predetermined amount from the position at which the imaging light beam starts to pass. .

(3) In the above item (1) or (2), the position detecting means has a photo reflector and a reflecting member. (4) In the above item (1) or (2), the position detecting means is a photo interrupter.

[0038]

As described above in detail, according to the present invention, exposure can be performed without adding a new position detecting member by using an exposure adjusting device, without increasing the size of the exposure adjusting device while maintaining the conventional component configuration. It is possible to provide an exposure adjusting device for a camera that can detect the occurrence of an abnormality when the abnormality occurs.

[Brief description of the drawings]

FIG. 1 is a schematic exploded perspective view of a camera exposure control apparatus according to an embodiment of the present invention, as viewed from the front side.

FIG. 2 is a diagram showing a detailed configuration of the plunger shown in FIG.

FIG. 3 is a diagram illustrating an initial closed state (state 1) of a series of state changes from a closing state to an opening state of a shutter blade in order to explain an operation of the exposure adjusting device of the embodiment.

FIG. 4 is a diagram showing, following FIG. 3, a position where the signal of the photoreflector changes, a state 2 in a series of state changes from closing to opening of the shutter blade.

FIG. 5 is a diagram showing a position, a state 3, in which a photographing light beam starts to pass, in a series of state changes from closing to opening of a shutter blade, following FIG.

FIG. 6 is a diagram showing a position, state 4, in which the shutter blade is fully opened, in a series of state changes from closing to opening of the shutter blade, following FIG.

7A is a diagram showing a timing chart of an opening / closing operation of a shutter blade including a state 1 to a state 4 in the exposure adjusting device at the time of low luminance, and FIG. It is a figure showing a timing chart of an opening and closing operation of a shutter blade including state 1 to state 4 in an adjustment device.

[Explanation of symbols]

 Reference numerals 1, 1a, 1b, 1c, 1d: shutter blades 2: housing 3, lever 4, lever spring 5, solenoid 6, iron core 7, closing spring 8, plunger 9, photo reflector 9a, light emitting unit 9b, light receiving unit 10 ... Reflecting member 11 ... Drive control circuit 12 ... Photometry unit 13 ... Film sensitivity detection unit 14 ... Relays unit 15 ... Warning unit

Claims (3)

[Claims] 1. Each of them is opened and closed by being rotated about a predetermined axis, and when in a closed state, blocks a photographing light beam passing through a photographing optical system. In the exposure adjusting device for a camera having a plurality of shutter blades retracted from the shutter blades, the shutter blades shield the central portion of the photographic light beam in the initial closed state, rotate in different directions, overlap with each other, and also in the open state. Second with a certain amount of overlap
And the third shutter blade, and the first and fourth shutter blades that shield the peripheral portion of the photographing light beam in the initial closed state, rotate in different directions from each other, and overlap the second and third shutter blades. Opening holes respectively provided near the tip portions of the third and fourth shutter blades rotating in the same direction; and in the initial closed state, the tip portion sides of the third and fourth shutter blades. And a position detecting means disposed on the movement locus of the opening and generating a signal when the third and fourth shutter blades move by a predetermined amount. If no signal is detected and a predetermined signal is not generated, the first, second, third and fourth
A determining means for determining that there is an abnormality in the exposure due to the opening / closing operation of the shutter blades. 2. The method according to claim 1, wherein the position detecting means includes:
A first or second binary state signal is generated according to the moving position of the shutter blade, and a first signal is generated in an initial state in which the shutter blade is closed, and the shutter blade is opened from the closed state to the open state. When moving in the opening direction to the state, the signal changes from the first signal to the second signal at a position where the imaging light beam is closed by a first predetermined amount before the position at which the imaging light beam starts to pass. Then, when the shutter blade moves in the opening direction, the second signal changes from the second signal to the first signal at a closed position that is a second predetermined amount before the position where the photographing light beam starts to pass. 2. The apparatus according to claim 1, wherein the second signal is generated at a position further moved in the opening direction by a third predetermined amount from a position at which the photographing light beam starts to pass. . 3. The camera is opened and closed by being rotated about a predetermined axis. When the camera is in a closed state, it blocks a photographing light beam passing through a photographing optical system. An exposure adjusting device for a camera having a plurality of shutter blades that retreats from the shutter blades, wherein, among the plurality of shutter blades, opening holes respectively provided in the vicinity of tips of two shutter blades; The two shutter blades are disposed on the movement locus of the opening hole, facing the tip portions of the two shutter blades;
Position detecting means for generating a signal in accordance with the state of the opening caused by the movement of the shutter blade; detecting the output signal state of the position detecting means; And a determining means for determining that the exposure due to the operation is abnormal.