JPS6378135A - Exposing mechanism - Google Patents

Abstract

PURPOSE:To accurately control the quantity of exposure without using any complex mechanism and to obtain an exposure control mechanism suitable to small screen size by starting the motion of a shutter release member associatively with the setting operation of a control means for setting the stop. CONSTITUTION:When an electromagnet 41 is powered on, a 1st motion of the shutter release plate 22 wherein the shutter release plate 22 begins to rotate by a 1st motion of the shutter release lever by a 1st motion of the stop securing lever 24 wherein the aperture securing lever 24 clock wise and if the electromagnet 41 is powered off, a 2nd motion of the shutter release member 22 is started by the motion at the time of aperture stopping by the aperture securing lever 24 where the aperture securing lever 24 rotates counterclockwise, thereby setting an aperture. At the same time, the outer peripheral end surface 22a of the shutter release plate 22 which is engaged by the engagement part 24a of the aperture securing lever 24 is disengaged, so that a shutter plate 22 restarts rotating as shown by an arrow.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an exposure mechanism used in a camera, and particularly to an exposure mechanism for a camera having an aperture and a shutter.

(Prior Art) Conventionally, various exposure control mechanisms have been considered for cameras that control the exposure layer using an aperture and a shutter. 2. Description of the Related Art So-called electronic cameras that record still images on magnetic disks have come into practical use.

The first major difference between such cameras and conventional cameras that use silver halide film is the size of their screens. For example, the screen size of the commonly used 35mm film is 24mm x 36mm, while the screen size of an image sensor, called % inch size, is about 4.8mm x 6.4mm, and the area ratio is 28mm. :1. Also, compared to silver halide film, C
The dynamic range (or latitude) of an image sensor such as a CD is quite narrow.

Therefore, compared to cameras using conventional silver halide film, the exposure mechanism used in electronic cameras has to pass through a smaller aperture size, and the exposure amount can be controlled to an extremely low level.
It is necessary to control J.

(Problems to be Solved by the Invention) By the way, the exposure control means of conventional electronic cameras are scaled-down versions of the means used in cameras using silver halide film, and in extreme cases, the aperture control means The shutter speed was based on the transfer period of one field of the television signal.For this reason, it was not possible to increase the number of mechanical functions or to control the exposure amount with high precision. Another problem is that the range of brightness that can be photographed is narrow.

[Means for solving problems]

The present invention was made to solve these problems, and the invention starts the movement of the shutter release member in conjunction with the aperture setting operation of the control means for setting the aperture. It is an object of the present invention to provide an exposure control mechanism that makes it possible to control the exposure amount with high precision without using a 3D device, and that can be applied to a small screen size.

It goes without saying that the exposure control mechanism according to the present invention is applicable not only to electronic cameras, but also to conventional cameras that use silver halide film.

The following is a description based on examples.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. Figure 1 is a plan view of the main parts of the exposure mechanism.
This shows a state in which charging has been completed.

(Blade and blade tensioning lever) In the figure, l is the aperture, 2 is the leading blade that blocks the light passing from the aperture 1, and 2a is the leading blade 2.
The engaging portion 2b provided on the leading blade 2 has this engaging portion 2a.
2C is a bottle provided on this protrusion 2b,
3 is a spring for driving the leading blade that urges the leading blade 2 in the clockwise direction, where the protruding part 2b provided with the bottle 2C and the engaging part 2a is provided, 3a is the hooking part of this spring 3, and 4 is the hooking part of the spring 3. This hook hook has a portion 3a on the rear blade provided in contact with the leading blade 2 which is biased by the spring 3, 4a is an engaging portion of this rear blade 4, and 4b is a portion 4b on the rear blade 4 where this engaging portion 4a is located. 5 is a spring for driving the rear blade that biases the rear blade 4 provided with the protrusion in the clockwise direction; 5a is a hook hooking portion of the spring 5;
This hook hook is an axis between the rear blade 4, which is biased by the spring 5, and the leading blade 2, which is biased by the spring 3, where the part 5a is located. The leading blade tensioning lever is adapted to bias both blades 2.4 clockwise around the shaft 6 by springs 3.5 and 7a.
is an engaging portion provided on the first branch of the leading blade tensioning lever 7, 7
b is the tip of the second branch of the leading blade tensioning lever 7 where the first branch is provided with this engaging portion 7a, 8 is the shaft of the leading blade tensioning lever 7 where this tip 7b is located, and 9 is the tip of this second branch. A spring that biases the lever 7 provided at one end of the pivotally supported leading blade tensioning lever 7 in the clockwise direction, and the elastic force of this spring 9 causes an engagement provided in the first branch of the leading blade tensioning lever 7. By pressing the portion 7a into engagement with the engaging portion 2a of the leading blade 2, the leading blade 2 is tightened in a predetermined position, and 10 is a trailing blade tensioner that tightens the trailing blade 4. 10a is an engagement part provided on the first branch of the rear blade tensioning lever 10, 10b is the tip of the second branch of the rear blade tensioning lever 10, 11 is the rotation axis of the lever 10, and 12 is the rear A spring is provided at one end of the blade tensioning lever 10, and the elastic force of this spring 12 causes the rear blade tensioning lever 10 to move to the first position.
By pressing and engaging the engaging portion 10a of the branch with the engaging portion 4a of the rear blade 4, the rear blade 4 is tightened in a predetermined position.

(Leading blade tensioning lever and trailing blade tensioning lever) The engaging part 7a of the first branch of the leading blade tensioning lever 7 engages with the engaging part 2a provided on the leading blade 2, and In the state in which charging is completed as shown in the figure, the leading blade 2 maintains a phase in which the aperture 1 shown by the chain line is shielded from light. Further, the leading blade tensioning lever 7, which is the tensioning lever for the leading blade 2, has a second branch.
The tip portion 7b is pressed against a pin 22b implanted in a shutter release plate 22, which is a shutter release member to be described later.

Further, the rear blade tensioning lever 10 is biased clockwise by a spring 12 around a shaft 11, and the engaging portion 10a of the first branch of the rear blade tensioning lever 10 is also provided on the rear blade 4. 1, and the state shown in FIG. 1 is maintained. After this, the blade tensioning lever 10 also has a second
There is a branch, the tip 10b of which is pressed against a tip 45b of an adsorption piece 45 of an electromagnet 44, which will be described later.

(Aperture plate and shutter release plate) Reference numeral 21 denotes an aperture plate which is an aperture member, and is biased clockwise as shown by an arrow A around a shaft 23 by a spring (not shown). Aperture aperture 21-1.2 corresponding to the aperture value determined by the photographic lens to be used.
1-2.21-3 are provided. In one embodiment of the present invention, apertures corresponding to the three values 21-1.21-2.21-3 are provided, but the number of apertures is not limited to three and may be provided as appropriate. It is something that can be done. Further, the outer peripheral portion of the aperture plate 21 is provided with a locking portion 21-a that can be engaged with a locking pawl 24c provided at one end of the aperture tightening lever 24, which will be described later.

21-b, 21-c, and 21-d are provided, and among these locking portions, 21-a and 21-b.

When 21-C engages with the locking claw 24c, the aperture apertures 21-1, 21-2, and 21-3 are opened [1 center is the optical axis center of the shadow lens 81 (not shown), in other words, It is configured to be located at the center of the aperture 1. In the state shown in FIG. 1, the locking pawl 24c of the aperture tensioning lever 24 and the locking portion 21-d of the aperture plate 21 are engaged.

Further, the diaphragm plate 21 is provided with a gear portion 21-e, which meshes with the gear 27, and the gear 27.degree. 28 and the pendulum 29 constitute a mechanical governor 30, which is a governor.
The rotational speed of the aperture plate 21 is matched.

A shutter release plate 22 is provided around the diaphragm plate 21 and the same axis 23, and similarly to the diaphragm plate 21, the shutter release plate 22 is biased clockwise as shown by the arrow A by a spring (not shown). A locking claw 22d that engages with the locking claw 24c of the aperture tightening lever 24 described above is also provided on the outer circumference of the release plate 22, and in the fully charged state shown in FIG. It is locked by a locking claw 24c. Also, this shutter release plate 2
2 has a bottle 22b planted therein, which presses the tip 7b of the aforementioned leading blade tensioning lever 7 before the end phase of the rotation of the shutter release plate 22, and rotates the leading blade tensioning lever 7 counterclockwise. It is designed to rotate in the direction.

The aperture tensioning lever 24, which has a locking pawl 24c that locks with a locking portion 22d provided on the shutter release plate 22, is urged counterclockwise by a spring 26 about a shaft 25. The engaging pawl 2 is connected to the first branch of the aperture tightening lever 24.
4a is provided, and comes to engage with the outer peripheral end 22a of the shutter release plate 22 described above when the aperture tensioning lever 24 rotates clockwise. Further, the second branch 24b of the aperture tensioning lever 24 is attached to an attraction piece 42 of an electromagnet 41, which will be described later.
It is pressed into contact with the tip end portion 42b of.

(Tension Adjustment Mechanism) Generally, it is desirable that the running characteristic of the shutter blade is such that the forming end of the exposure slit has a constant speed while running within the aperture. However, when the shutter blade is driven by a spring as in one embodiment of the present invention, the ideal result may vary depending on the spring characteristics, the direction of action of the elastic force of the spring, manufacturing variations in the spring, and various variations in the shutter blade system. In order to obtain driving characteristics close to , it is necessary to make minute adjustments to the driving force (hereinafter simply referred to as fine adjustments).

Below, a shutter blade speed adjusting member for performing this fine adjustment will be explained based on FIGS. 1 and 5. In the figure, 31 is: l! This is a blade speed adjustment member for the rear blade 4, which is an adjustment member, and is rotatable around a shaft 32 provided on the substrate 50 of the exposure mechanism. A hook portion 31b is formed between the shaft 32 and the ratchet 31a for hanging the hook portion 5a of the spring 5 for driving the rear blade. 33 is a ratchet pawl whose tip 33a engages with the ratchet 3fa, and is elastically formed as a part of the base plate 50, and the locking force against the base plate 50 is the rotational force due to the elastic force of the spring 5. The substrate 50 is provided with a tilt prevention portion 34 for preventing tilt that occurs when the spring 5 is activated.

When the blade speed adjusting member 31 can rotate the ratchet 31a by, for example, one tooth, the hook hook on which the hook portion 5a is hung is determined by the distance from the portion 31b to the rotation center and from the ratchet 31a portion to the rotation center. Since the rotation of the hooking portion 31b is reduced in accordance with the ratio to the distance, the driving force can be finely adjusted.

This can be understood from the following points. Adjustment of the driving force of the spring 5 of the rear blade 4 is performed when the spring 5 is in a tensioned state.
This is done by changing the length of by a minute amount,
In order to change the length of the spring 5, the ratchet 31a is attached to the shaft 32.
Since the hooking length that occurs when the ratchet 31b is rotated around the rotation radius is smaller than the rotation length of the ratchet 31a on the pitch circle, it is easy to finely adjust the driving force. Furthermore, in this case, since the hook portion 5a is located on the shaft 32 side, the force applied in the tangential direction on the circumference of the pitch circle of the ratchet 31a to adjust the driving force of the spring 5 is stronger than the force applied to the pitch circle of the ratchet 31a. Since the hooking force is smaller than the driving force of 5 according to the ratio of the rotation radius of the part 5a and the ratchet 31a,
It is easy to finely adjust the driving force of the spring 5.

What has been explained above is that the hook hook is attached to the leading blade 2 where the part 3a is located.
The same applies to the blade speed adjusting member 31', so the description will not be repeated.

Reference numerals 42 and 45 are attraction pieces for the electromagnets 41 and 44, which are rotatable around shafts 43 and 46. When the electromagnets 42 and 45 are not energized, springs (not shown) hold the attraction surfaces of each of them. 42a.

45a is apart from the yokes 41a and 44a.

When the electromagnet 41 is energized, the adsorption piece 42 rotates counterclockwise around the shaft 43, and its tip 42b presses the tip 24b of the aperture tensioning lever 24, causing the aperture tensioning lever 24 to rotate. let

Furthermore, when the electromagnet 44 is energized, the adsorption piece 45 rotates clockwise around the shaft 46, and its tip 45b presses the tip 10b of the rear blade tensioning lever 10. Rotate counterclockwise.

(Bell Crank and Charge Lever) A bell crank 51 is rotatable about the shaft 23, and has a bin 51a at one end and a long hole 51b at the other end. A bottle 53a installed in the charge lever 53 is loosely engaged with the elongated hole 51b. Further, 52 is also a bell crank which is rotatably provided around the shaft 6, and has a bottle 52a planted in one end thereof and a long hole 52b provided in the other part. A bottle 53 is also installed in the charge lever 53 in this elongated hole 52b.
b is playing.

When this charge lever 53 is moved to the right by a certain amount in FIG. 1, the bell crank 51.5
2 rotate counterclockwise, and the bottles 51a and 52a
through the aperture plates 21., respectively. Shutter release plate 22 and leading blade 2. The rear blades 4 are charged, and these will be described in detail later.

55 is a switch that generates a shutter start signal;
When the leading blade tensioning lever 7 rotates counterclockwise, the engaging portion 7
The contact piece 55a is pressed by the back surface of the contact piece 55a to break contact with the contact piece 55b.

(Blade relative phase adjustment mechanism) Reference numeral 47 denotes a board that is movable around the shaft 6 of the shutter blades 2 and 4 by means of a guide bin 48 provided on the board 50. lever 10
The shaft 11 of the electromagnet 44 and the shaft 46 of the electromagnet 44 are mounted,
49 is a screw for fixing this substrate 47 to the base Fi 50.

By the way, when the base plate 47 is rotated, the rear blade tensioning lever 10 is also rotated about the shaft 6, and the rear blade tension lever 10 is rotated about the shaft 6, and the rear blade 4 is rotated through the engaging part 4a that is engaged with the engaging part 10a. It becomes possible to adjust the phase with respect to the leading blade 2 when the charging is completed. Therefore, by changing the relative phase of both blades 2 and 4 at the start, it is possible to reduce mechanical and electrical variations that affect the shutter speed. Further, since the base plate 47 rotates the shaft 11 about the rotation center 6 of the blade, the relationship between the engaging part 4a of the trailing blade 4 and the engaging part 10a of the trailing blade tensioning lever 10, The relationship between the tip iob of the lever 10 and the tip 45b of the suction piece 45 can be kept constant at all times, without affecting the breakage characteristics of the tensioned portion.

In order to change the relative phase between the leading blade 2 and the trailing blade 4, if the pin 2C that contacts the convex portion 4b of the trailing blade 4 is configured as an eccentric rotation pin, the engagement of the leading blade tensioning lever 7 can be changed. Since the relationship between the joining part 7a and the engaging part 2a of the leading blade 2 and the relationship between the trailing blade tensioning lever 10 and the engaging part 4a of the trailing blade 4 are different from the set state, the breakage characteristics of the tensioning part are Therefore, in one embodiment of the present invention, the wire is constructed in a disconnected manner so that stable breaking characteristics can be obtained at all times.

One embodiment of the present invention is constructed as described above, and its operation will be explained below.

FIG. 7 is a timing chart showing the operating states of the main parts.

(a, aperture and shutter speed) First, when the camera is started, measurements (not shown) are taken.

The combination of aperture and shutter speed is determined based on the brightness of the subject using calculations, drive circuits, etc.

(b, Setting the aperture) When the electromagnet 41 rotates, the adsorption piece 42 rotates counterclockwise, and its tip 42b engages the tip 2 of the aperture tensioning lever 24.
4b and rotate the throttle tensioning lever 24 clockwise. As a result of this rotation, the aperture plate 21 and the shutter release plate 22, which were locked by the locking claw 24c, separate from the locking claw 24c as shown in FIG. 2 and begin to rotate in the direction of the arrow. The outer circumferential end 22a of the shutter release plate 22 is engaged with the engaging portion 24a of the aperture tensioning lever 24, and its rotation is stopped.

On the other hand, the aperture plate 21 is connected to the engaging portion 24 of the aperture tensioning lever 24.
Since it is not engaged with a, it continues to rotate in the direction of the arrow. This situation is shown in FIG. 2 for the case where the aperture opening is set to 21-2. By the way, as mentioned above,
Since the rotational speed of the aperture plate 21 is matched by the mechanical governor 30, the time required for each aperture to reach the center of the aperture 1 after the electromagnet 41 is energized is approximately fixed. Therefore, as shown in FIG. 7, when the electromagnet 41 is de-energized at the arrival time t of the diaphragm opening 21-2, the diaphragm tensioning lever 24 is rotated counterclockwise by the bias of the spring 26. The locking claw 24c and the locking portion 21b provided on the outer circumference of the aperture plate 21 engage with each other,
The aperture 21-2 is set. (Figure 7 tz).

At the same time, the outer peripheral end 22 of the shutter release plate 22, which had been engaged with the engaging part 24a of the aperture tensioning lever 24,
The engagement with a is released, and this shutter release plate 22
resumes rotation in the direction of the arrow.

The start of movement of the shutter release plate 22 caused by the start of movement of the aperture tensioning lever 24, which is a control member, when setting the aperture can be summarized as follows.

When the electromagnet 41 is energized, the first movement of the aperture tensioning lever 24, in which the aperture tensioning lever 24 begins to rotate clockwise, causes the first movement of the shutter release plate 22, in which the shutter release plate 22 begins to rotate. start exercising,
Next, when the power to the electromagnet 4 is cut off, the aperture tension lever 2
The second movement of the shutter release plate 22 is started by the movement of the aperture tensioning lever 24 when setting the aperture, in which the aperture tensioning lever 24 begins to rotate counterclockwise. Aperture is set.

(C, Occurrence of shutter start toy No. 3) The shutter release plate 22 rotates, and finally the stopper pin 54
It stops when the outer peripheral end 22a comes into contact with the outer peripheral end 22a.
Immediately before that, the pin 22b provided on the shutter release plate 22 presses the tip 7b of the leading blade tensioning lever 7,
Rotate the leading blade tensioning lever 7 counterclockwise. Due to this rotation, the engagement between the engaging portion 7a and the engaging portion 2a is released, and the leading blade 2 starts rotating due to the driving force of the spring 3, and the contact piece 55a of the shutter start signal switch 55
The contact between the contact piece 55b and the contact piece 55b is released, and a shutter start signal is generated. This situation is shown in Fig. 3 (Fig. 7 ts
, +4) - (d, exposure) In response to this shutter start signal, the electromagnet 4 is activated after a certain predetermined time by a shutter control circuit (not shown).
4 is energized, the adsorption piece 45 rotates clockwise, and its tip 45b rotates the rear blade tensioning lever 10 counterclockwise, thereby releasing the engagement between the engaging part 10a and the engaging part 4a. Then, the rear blade 4 is rotated clockwise by the driving force of the spring 5, and the exposure is completed. This situation is shown in FIG. 4 (FIG. 7, t).

t6).

The case where the aperture aperture is 21-2 has been described above, but the same applies when the aperture aperture is set to 21-2 or 21-3, and as shown in FIG.
The time corresponding to tl I +t+2.

(e, charge) In the state of completion of travel shown in FIG. 4, charge lever 53 (
(see Figure 1) forward to the right, the bell crank 5
1.52 rotate counterclockwise. At this time, the end surface 21f of the aperture plate 21 and the end surface 22c of the shutter release plate 22 are pressed by the bottle 51a installed in the bell crank 51, and both plates 21 and 22 are rotated counterclockwise, as shown in FIG. The state shown in is set.

Further, the protruding portion 2b of the leading blade 2 is pushed by the pin 52a implanted in the bell crank 52, and the leading blade 2 is rotated counterclockwise. At this time, the protruding part 4b of the rear blade 4 is also pressed via the pin 2C provided on the protruding part 2b, and the rear blade 4 also rotates counterclockwise. In this way, both wings 2.
4 are both set to the state shown in FIG.

When the charge lever 53 is moved back to the position shown in FIG. 1 after these settings are completed, the exposure operation as described above becomes possible again.

As explained above, according to one embodiment of the present invention, it is possible to precisely control each aperture and shutter, the number of parts is small, and the exposure control system is suitable for small-screen cameras. You can get the mechanism,
In order to use the kinetic energy of the shutter release plate 22 to trigger the start of the leading blade 2, always stable cutting characteristics were selected, and the energization state of the electromagnets 41 and 44 was short, and the power consumption was small. It has the effect of finishing.

In one embodiment of the present invention, the prediction of the position of the aperture is performed using the aperture plate 2.
1 running time (t0 to tll, t, t in Figure i7)
, □), but in order to control the aperture more reliably, an encoder consisting of a contact piece and a code plate is attached to the aperture plate 21 to generate a position signal, so that the electromagnet 41 may be controlled.

Further, in one embodiment of the present invention, the aperture plate 21° and the aperture aperture 21-1.21-2.21-3 are provided to control the aperture value in stages, but a general method using an aperture ring and aperture blades The claws 21-a, 21-b, 21 are attached to the aperture ring using an aperture mechanism.
It is also possible to more finely control the aperture value by providing claws corresponding to -c and 21-d.

Further, in one embodiment of the present invention, the ratchet pawl 33 is configured as a cantilever beam, but it may be configured as a double-sided beam as shown in FIG. 6 in order to increase the reliability of blade adjustment.

Therefore, in one embodiment of the present invention, there are two rotary traveling type blades, but even if there are three or more blades, the same effect can be obtained.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to precisely control the aperture and shutter, the number of component parts is small, and an exposure mechanism suitable for small-screen cameras can be obtained. Since the start of the leading blade is triggered by the kinetic energy of the shutter release member, stable cutting characteristics can be obtained and power consumption can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the exposure mechanism of an embodiment of the present invention in a fully set state, Fig. 2 is a plan view showing the aperture plate in a started state, and Fig. 3 is a plan view when the shutter is in the exposure state. FIG. 4 is a plan view showing the completed state of the rotation light,
Figure 5 is a perspective view of the tension adjustment mechanism of the spring for driving the blade;
FIG. 6 is a perspective view of a tension adjustment mechanism according to another embodiment of the present invention, and FIG. 7 is a timing chart for explaining the operation of one embodiment of the present invention. In the figure, 1 is the aperture, 2 is the leading blade, 3 is the spring for driving the leading blade, 4 is the trailing blade, 5 is the spring for driving the trailing blade, 7 is the leading blade tension lever, and 10 is the trailing blade tension lever. , 21 is an aperture plate, 22 is a shutter release plate, 24 is an aperture tensioning lever, 30 is a mechanical governor, 31 is a blade speed adjusting material, 33 is a ratchet pawl, 41.44 is an electromagnet, 42.
45 is a suction piece, 47 is a board, 48 is a guide bin, 50 is a board, and 55 is a shutter signal switch. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (3)

[Claims] (1) An exposure mechanism characterized in that a movement of a shutter release member is started in conjunction with an aperture setting operation of a control member for setting an aperture. (2) The exposure mechanism according to claim 1, wherein the shutter release member is locked together with the aperture member by the control member in an initial state. (3) In claim 1, the shutter release member is moved to a first position by the first movement of the control member.
The exposure mechanism is characterized in that the second movement is started by the aperture setting movement by the control member.