JPH02251829A - Safety mechanism for lens barrier - Google Patents

Abstract

PURPOSE:To effectively prevent the damage of a joint part by providing a buffer mechanism on the joint part of a driving source and a lens barrier and permitting the buffer mechanism to absorb external force that may affect the lens barrier. CONSTITUTION:When a first lever 53 is driven by the driving source 7, a second lever 57 that is connected to the first lever 53 with a first spring member 55 is driven, and the lens barrier 58 follows the energizing force of a second spring member 56, or moves against the energizing force of the member 56, thereby opening and closing an optical system is performed. When external force such as misoperation acts on the lens barrier 58 in its closing position to shift it from the closing position to an opening position, the second lever 57 is driven against the energizing force of the second spring member 56. The energizing force of the first spring member 55 becomes greater, however, the first lever 53 is not driven. Consequently, unexpected photographing due to external force does not occur in the joint part of the driving source 7 and the first lever 59, and thereby the damage of the joint part can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a lens barrier that can effectively prevent damage to the drive mechanism of the lens barrier against forces applied due to erroneous operation of the lens barrier in optical equipment such as cameras. Regarding safety mechanisms.

BACKGROUND OF THE INVENTION Hitherto, various structures have been known as safety mechanisms for lens barriers of this type. For example, if the lens barrier is 1
Some devices use two spring members to bias the lens in the direction of closing the lens barrier.

For example, when a safety mechanism with such a structure is adopted in a camera that uses a planetary gear to switch the power transmission from the motor to a lens exchange drive mechanism and a lens barrier drive mechanism, the planetary gear or the lens barrier drive mechanism When the lens barrier is engaged with the lens exchange drive mechanism, the lens barrier is held immovably from its stopped position, while when the planetary gear is engaged with the lens exchange drive mechanism, the connection between the lens barrier and the motor is maintained. Since it comes off, the lens barrier can be moved from its stopped position to another position by external force.

Problems to be Solved by the Invention Therefore, when the safety mechanism of the above structure is used in a camera etc. that switches the drive mechanism as described above, if the drive mechanism of the lens barrier is engaged with the motor, the photographer may accidentally If an attempt is made to open the lens barrier, an overload will be generated on the connection between the lens barrier and the motor, and this connection may be damaged.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a lens barrier safety mechanism that can effectively prevent damage to the lens barrier even in the above-mentioned switching type camera. .

Means for Solving the Problems In order to achieve the above object, the present invention provides a buffer mechanism at the connecting portion between the drive source and the lens barrier, so that even if an external force acts on the lens barrier, the buffer mechanism prevents the external force from acting on the lens barrier. The lens barrier is configured to absorb this and effectively prevent damage to the connecting portion between the lens barrier and the drive source. That is, a drive source for driving the lens barrier to open and close with respect to the optical system, a first lever connected to the drive source and driven, and a first lever connected to the first lever by a first spring member. The lens barrier is always biased in a predetermined direction by two spring members and includes a second lever to which the lens barrier is connected.

Further, in the above configuration, the predetermined direction in which the second spring member is biased may be a direction in which the lens barrier is moved to a lens barrier closed position that closes the optical path of the optical system. .

Further, in the above configuration, the biasing force of the first spring member can be configured to be larger than the biasing force of the second spring member.

In the above configuration, the first drive source is driven by the drive source.
When the lever is driven, the second lever connected to the first lever by the first spring member is driven, and the lens barrier follows the urging force of the second spring member, or the second lever is connected to the first lever by the first spring member. It moves against the urging force of and performs an opening/closing operation with respect to the optical system. When the lens barrier is located at the position where the optical path of the optical system is closed, that is, the lens barrier closed position, an external force acts on the lens barrier due to an erroneous operation, and the lens barrier is moved from the closed position to the open position, that is, the position where the optical path of the optical system is opened. When the lever is moved to , the second lever is driven against the biasing force of the second spring member, but the biasing force of the first spring member only increases and the first lever is not driven.

Therefore, since the first lever connected to the drive source is not driven, the connection portion between the drive source and the first lever is not affected by the erroneous operation of the lens barrier, and the connection portion between the drive source and the first lever is not affected. Damage is effectively prevented. Further, when the external force is removed from the lens barrier, the biasing force of the second spring member acts on the second lever connected to the lens barrier, so the biasing force of the second spring member acts on the second lever connected to the lens barrier. , the second lever is driven to reliably move the lens barrier to its original closed position.

Embodiments according to the present invention will be described in detail below with reference to the drawings.

An electronic still camera equipped with a lens barrier safety mechanism according to this embodiment will be described.

FIGS. 1(a) to 1(e) show external views of an electronic still camera which is an embodiment of the present invention. As shown in FIG. 1(c), the camera includes a flash 70, a photometer 80, a part of the viewfinder 40, and a lens barrier 58 in normal conditions.
The visible lens aperture is located. Figure 1 (
As shown in b), a release switch 5, a telephoto switch 3 for changing lenses, and a close-up switch 4 are arranged on the top surface of the camera. Further, as shown in FIG. 1(a), a main switch 90 for turning on or turning off the power is arranged on the rear surface of the camera. Inside the camera, an image sensor 25 is arranged behind the lens barrier 58 via a photographing lens system, and the image taken by the image sensor 25 is subjected to image processing, and then transferred to a floppy disk set in the camera by a deck section 80. recorded on the disc.

FIG. 1(f) shows a system diagram of the camera of this embodiment. Note that in this figure, a lens barrier drive section and a lens rear block 2, which will be described later, are omitted for the sake of simplification. The photographic lens system of this embodiment includes two main optical systems A (Ia),
When the front lens block l that holds B (lb) and the main optical system B (1b) are in the photographing optical path (optical path center and a rear lens block 2 that holds a sub-optical system C (2c).

These two blocks 1.2 are 90° to the lens rotation axis 22.
It is rotatably supported within the range of 1.2
0° or 90° with snap spring 16.17
It is pressed and fixed in the position.

As shown in Table 1, the photographic optical system of this example is a block in front of the lens! It can be used as three different types of photographic lenses depending on the position of the rear lens block 2. Figure 2 is a model representation of the photographic optical system in each state.
FIG. 2(a) shows the state of the wide-angle lens, FIG. 2(b) shows the state of the telephoto lens, and FIG. 2(C) shows the state of the close-up lens.

Table 1 In this example, the photographing lens has a fixed focus in each of the three states, the wide-angle lens is f9/F3.5, the telephoto lens is f20/F3.5, and the close-up lens is f2.
0/F 16. The reason why the F number of a close-up lens is increased is to widen the depth of field, and since the possible shooting distance (focusing distance M) is short, it is necessary to use a flash when there is insufficient illumination. The light is emitted to take pictures. FIG. 3 shows the distance that can be photographed with each lens and the screen ratio when photographing a person.

In this embodiment, since the taking lens is in a standard state as a wide-angle lens, two operating members, a telephoto switch 3 and a close-up switch 4, are provided as operating members for changing the magnification. When these operation switches are operated, the photographic lens is switched from the wide-angle lens state to each state, and when the operation of the operation switches 3.4 is stopped, the wide-angle lens state is returned again.

Further, when the photographing lens is a telephoto lens or a close-up lens and the release switch 5 is turned on to take a picture, the lens automatically returns to the wide-angle lens state after exposure is completed.

Further, a lens barrier 58 (see FIG. 6), which will be described later, opens when the release switch 5 is turned on to prevent burn-in of the image sensor 25, and closes after exposure is completed.

That is, in this embodiment, an image sensor that can control the start and end of charge accumulation is used as the image sensor 25, and the appropriate exposure can be adjusted by changing the accumulation time without using a light amount adjustment means such as an aperture. It does not have an aperture. For this purpose, the lens barrier 58
If the lens barrier 58 is open all the time, image capture will occur in the image sensor 25 when strong external light is incident, so the lens barrier 58 is opened only during exposure.

Now, the switching operation from the wide-angle lens state to the telephoto lens state will be explained (see FIG. 1(f') and FIG. 4). The step numbers in the text are the step numbers in the flowchart of FIG. As shown in FIG. 11(a), when the photographer turns on the telephoto switch 3 (step 5lot), the motor 7 starts to rotate normally by the camera microcomputer 6 (step 5102). Here, a worm gear 7a is attached to the motor 7 in this embodiment and in the figures, and the direction in which the reduction gear 8, which is a worm wheel, is rotated in the direction of the arrow in the figures is determined by the normal rotation of the motor 7 and the opposite direction. will be expressed as the reversal of the motor 7.

In addition, for gear trains and rotating bodies other than the motor 7, clockwise rotation represents a forward direction, and counterclockwise rotation represents a reverse direction. When the motor 7 rotates forward in step 5102, the sun gear 9 rotates in the forward direction via the reduction gear 8. When the sun gear 9 rotates in the forward direction, the planetary gear 10 meshes with the input gear lla of the lens switching gear All, which is a four-stage gear, and transmits the rotation, so that the lens switching gear All also rotates in the forward direction. The lens switching gear All is provided with a lens state detection means 12, and during one rotation of the lens switching gear A11, signals representing three states are sent to the lens state detection means! Output from 2.

FIG. 5(a) shows a pattern diagram of a patterned substrate 12a which is one element of the lens state detection means 12 of this embodiment. The lens state detection means 12 detects pattern 1 (12-1) and pattern 2 (12-1) by sliding a section 12b fixed to the lens switching gear All on the pattern board 12a.
2) is connected to the GND line (12-0) to obtain a signal. FIG. 5(b) is a model diagram in which the rotation angle of the lens state detection means 12 is taken as the horizontal axis, and the time when conduction with the GND line (12-0) is a Lo signal and the time when there is no conduction is a Hi signal. The relationship between each lens pattern and each lens state is summarized in Table 2.

As can be seen from Table 2, Figure 5(b), the status signals of the wide-angle lens, telephoto lens, and close-up lens are output approximately every 120° (three equal parts of one rotation), and each status signal is output. Since the interval in which the lens is in each state is narrower than the interval in which the lens is in each state, the photographing lens is always in that state when each state signal is output.

In the close-up lens state, as shown in FIG. 5(b), the section where lens pattern 2 (12-2) becomes Lo is widened. This is related to the operation of returning to the wide-angle lens state in the lens switching operation, which will be described later, but will be briefly explained here first. If lens pattern 1 (12-1)
If the ranges of and lens pattern 2 (12-2) are set to be exactly the same, lens pattern substrate 12a and section 12
Due to the relative position error with b, the pattern error on the pattern board 12a, the error of the intercept 12b, etc., the signal indicating the state of the wide-angle lens, that is, the lens pattern + (12-1) becomes Lo.
It is also possible that a Hi signal is output from lens pattern 2 (12-2), which could lead to malfunction, so output telephoto lens status signals that do not lead to malfunction on both sides of the section where the close-up lens status signal is output. There are sections.

Furthermore, the reason why the pattern for outputting each status signal is varied is that it takes a certain amount of time from when the signal is output from the lens status detection means I2 until the motor 7 stops, and also when the motor 7 stops, the lens This is to ensure that the same status signal is output from the status detection means.

The lens switching operation will be described below with reference to FIG. Figures 4(b), (d), (f), (h), (D, and (1)) respectively show the operation of the lens front block I, and Figure 4(c)
, (e), (g), (i), (k),
(m) shows the operation of the rear lens block 2, respectively. The forward rotation of the motor 7 as described above causes the lens switching gear All to rotate in the forward direction, and when the lens state detection means 12 outputs a telephoto signal to the camera microcomputer 6 (step 5103
, 5104), and the motor 7 is stopped by the camera microcomputer 6 (step S I 05). At this time, the section 12b stops at about 120° on the lens pattern substrate 12a, indicating a telephoto lens state. Lens switching gear All and lens switching gear C14 are both partially toothed gears, and although the gears are not connected in the wide-angle lens state (Fig. 4 (b) and (c)), lens switching gear A11 starts rotating. Then, the gear part 11b meshes with the gear part 14c, and the lens switching gear All and the lens switching gear CI4
The gears 11b and 14c start to engage with each other (FIGS. 4(d) and (e)), and the gears 11b and 14c are disengaged before the motor 7 stops. Here, it is the first output gear portion 11b of the lens switching gear All, which is a four-stage gear, that transmits meshing rotation from the lens switching gear All to the lens switching gear C14 (see FIG. 4(a)). Above lens switching gear C14
When the lens rotates, the first gear portion 14a of the gear C14 and the gear portion 1d of the lens front block 1 engage with each other, so that the lens front block 1 rotates around the lens rotation axis 22.

This lens front block l has a snap spring A1B.
The biasing force is acting on the lens switching gear Al.
When the lens switching gear C14 disengages, the lens front block l has rotated to such an extent that the direction of its biasing force is reversed. Therefore, the snap spring AI6 exerts an urging force on the lens front block 1 to suppress and fix the block 1 to the lens positioning B24. Therefore, the photographing lens is switched to a telephoto lens state, and the lens front block l and gear parts 1d and 14a are
Lens switching gear C14, which is always connected in gear via
is also fixed in the position shown in FIGS. 4(f) and 4(g). Further, the lens switching gear C14 and the lens switching gear B13 are always connected in gear via the second gear part 14b and the first gear part 13a and are fixed at the positions shown in FIGS. 4(f) and 4(g).

Next, the switching operation from the wide-angle lens state to the close-up lens state will be described. When the photographer turns on the close-up switch 4 (step 5201)
, the camera microcomputer 6 starts the motor 7 to rotate in the normal direction, similar to the switching operation to the telephoto lens state (step S2).
02). Then, in the same way as the switching operation from the wide-angle lens state to the close-up lens state, the lens switching gear A
ll rotates in the forward direction. In this case, the motor 7 continues to rotate until the lens state detection means 12 outputs a close-up signal. That is, the patterned substrate 1
The above rotation is continued until the section 12b slides on the section 2a and stops at a position of approximately 240 degrees.

Similar to the switching operation from the wide-angle lens state to the telephoto lens state, until the telephoto signal is output from the lens state detection means 12, only the front lens block l is rotated, and the main optical system of the photographing lens is rotated. is main optical system B (1b)
can be switched to After that, during the rotation until the close-up signal is output, the second output gear section 11c of the lens switching gear All and the second gear section 15b of the lens switching gear C15 as shown in FIGS. 4(h) and 4(i). The first gear portion 1 of the lens switching gear C' 15 is
The lens rear block 2, which is gear-coupled with the lens rear block 5a through the gear portion 2d, rotates by the rotation of the lens switching gear C15. When the gears 15a and 2d are disengaged, the rear lens block 2 is pressed and fixed to the lens positioning B24 by the snap spring B17, and the rear lens block 2 is in the state shown in FIGS. It is in a state where it is switched to the position 2 or 906.

A short time after the gears 15a and 2d are disengaged, a close-up signal is output from the lens state detection means 12 (steps 5203 and 5204), and the motor 7 is stopped (step 52G5). By the above operation, the rear lens block 2 is switched to the 90° position, and the sub optical system C is placed on the image sensor side of the main optical system B (1b).
(2c) is inserted, and the switching operation to the close-up lens state is completed.

The following describes the operation when the photographer cancels (turns off) the operation of the telephoto switch 3 after switching the photographic lens to the telephoto lens state. In other words, the photographer presses the telephoto switch 3.
When the operation is stopped (step 5I06), the camera microcomputer 6 causes the motor 7 to start rotating normally (step 510).
7) Continue rotation until a wide-angle signal is output from the lens state detection means 12. Because of this operation, it is necessary to devise a pattern in the close-up lens state of the lens state detection means I2 described above. When the motor 7 continues to rotate, the lens switching gear All rotates in the forward direction from the 120'' position to the 360° (0°) position. After the photographic lens is switched to the close-up lens state (Fig. 4 (j), (k)) by the meshing operation of both gear parts 11c and i5b, the state shown in Fig. 4 (1), (m) is reached. The third output gear section lid of the lens switching gear A (11) and the second output gear section lid of the lens switching gear B13
Due to the meshing of the gear part 13b, the lens switching gear B13
rotates in the opposite direction. Therefore, the lens switching gear B13
Since the lens switching gear C14, which is always connected through the gear parts 13a and I4b, is rotated in the forward direction, the meshing between the gear part 14a of the lens switching gear C14 and the gear part 1d of the lens front block l is prevented. Through this, the lens front block l rotates in the opposite direction of the switching operation from the wide-angle lens to the telephoto lens. Here again, the lens switching gear All
When the gear parts 11d and +3b of the lens switching gear BI3 are disengaged, the lens front block l is pressed and fixed to the lens positioning A23 by the snap spring A16, and its position is fixed, and the lens changes to the wide-angle lens state. be returned. At this time, the lens state detection means 12 outputs a wide-angle signal (step 5108,
5109), the motor 7 is brought to a stopped state (step S110).

According to the above explanation, the rotational force from the motor 7 is applied to both the gear parts 11 of the lens switching gear All and the lens switching gear B13.
d, the lens front block l due to the meshing action of 13b.
However, in this example,
The front lens block 1 and the rear lens block 2 are configured in such a shape that when the front lens block 1 returns from the position in the close-up lens state to the position in the wide-angle lens state, it returns while pushing the rear lens block 2. Therefore, the rear lens block 2 is also returned to the wide-angle lens state,
Lens positioning A2 by snap spring B17
3 and becomes the wide-angle lens state shown in FIGS. 4(b) and 4(c). That is, as shown in FIG. 10, the rear lens block 2 has a vertical wall 2Q, and the vertical wall 2g overlaps the cylindrical portion 1 of the front lens block 1 in the front-rear direction. Therefore, as the front lens block l moves from FIG. 4 (D) to FIG. 4 (12) and FIG. Figure 4(k) to Figure 4(
m), then moves to Fig. 4(c).

Next, an explanation will be given of the operation when the photographer cancels (turns off) the operation of the close-up switch 4 after switching the photographic lens to the close-up lens state. When the photographer stops operating the close-up switch 4 (step 5)
206), similarly to when the operation of the telephoto switch 3 is stopped in the telephoto lens state, the motor 7 continues to rotate normally until a wide-angle signal is output from the lens state detection means 12 (step 5207). In this case, the third output gear lid of the lens switching gear All and the lens switching gear B are connected in the same way as when the operation of the telephoto switch 4 is stopped in the telephoto lens state.
13, the lens front block 1 and the lens rear block 2 are moved as shown in FIG. 4(b).
After returning to the wide-angle lens state as shown in (c) and outputting a wide-angle signal (steps 8208 and 5209), the motor 7 is stopped (step 5210).

However, the feature of the lens switching operation in this example is that the wide-angle lens →
The lens is looped in one direction from a telephoto lens to a close-up lens to a wide-angle lens, and the lens can be switched by rotating the motor 7 in only one direction.

Next, the operation when photographing will be described below.

First, the photographer presses the release switch 5 while using the wide-angle lens.
The case where the switch is turned on will be explained based on FIG. 11 (Q).

When the photographer turns on the release switch 5 (step 5)
30J), a signal is manually input to the camera microcomputer 6, and the camera microcomputer 6 causes the motor 7 to rotate in the opposite direction to that during the lens switching operation (step S3028 and subsequent steps are referred to as reverse rotation). Then, the sun gear 9 rotates in the opposite direction via the reduction gear 8, and the planetary gear IO moves away from the lens switching gear All and meshes with the barrier drive gear 51. Therefore, planetary gear! The rotation is transmitted from 0 to the barrier drive gear 51, and the barrier drive gear 51 rotates in the opposite direction. The barrier drive gear 51 is provided with a barrier state detection means 52, which outputs a barrier open signal to the camera microcomputer 6 at the position of the barrier drive gear 51 corresponding to the barrier open position (step 5303), thereby controlling the motor 7. Stop Step 5
304), the system starts charge accumulation in the photographing element 25 by generating a barrier open signal (step 5305). After the charge accumulation is completed, the camera microcomputer 6 starts the motor 7 to rotate in reverse again (step 8306), the barrier drive gear 51 also rotates in the opposite direction, and the barrier drive gear 51 corresponding to the barrier closed position is detected by the barrier position detection means 52.
A barrier close signal is output at the position (step 5307
), the motor 7 is stopped (step 530B).
.

Hereinafter, the operation of the lens barrier will be briefly explained based on FIG. 6. FIG. 6(a) shows the barrier open state, and FIG. 6(b) shows the barrier open state. When the barrier drive gear 51 is in the state shown in FIG. 6(a), the barrier state detection means 52 outputs a barrier close signal, and the barrier drive gear 5! In the state shown in FIG. 6(b), the barrier state detection means 52 outputs a barrier open signal. Here, as shown in Table 3 below, the barrier open signal means that the barrier pattern 1 is Lo and the barrier pattern 2 is Hi. Also, the barrier close signal is generated when barrier pattern 1 is Hi and barrier pattern 2 is high.
means that is Lo.

Table 3 First, the crank mechanism that opens and closes the barrier will be explained.

The lens barrier 58 is interposed between each lens and the image sensor 25 and acts as a barrier guide between a barrier closed position where the lens blocks light rays entering the image sensor 25 and a barrier open position where the lens is retracted from between both members. Move according to the guidance of 59. That is, the protrusion 5 at the lower end of the lens barrier 58 in FIG.
8a moves within the groove of the barrier guide 59,
The lens barrier 58 smoothly moves between the two positions. This lens barrier 58 is always urged toward the barrier closed position by a barrier spring 856. That is, Fig. 6 (g
), the barrier spring B56 is actually a torsion coil spring, and after being charged in the direction of the arrow in FIG. , the other end 56b is locked to the fixed part.

One end 57d of a barrier drive lever B57 is pivotally attached to the upper end of the lens barrier 58 in FIG. As shown in FIG. 6(e), the other end 57c of this barrier drive lever B57
is pivotally attached to the base end portion 54c of the substantially fan-shaped barrier drive connecting plate 54, and has a protrusion 57a on the lower surface of the intermediate portion thereof. The barrier drive connecting plate 54 has a concave groove 54a extending in an arc toward the barrier drive lever side on its surface, and the barrier drive lever B57 is movable in the concave groove 54a along the concave 11154a. The protrusion 57a is fitted. One end of the barrier drive lever A53 is pivotally attached to the back surface of the barrier drive connection plate 54 by a pivot pin 54d on the lower surface of the barrier drive connection plate 54, while the other end of the barrier drive lever A53 is pivoted by a pivot pin 51a. It is pivotally connected to the upper surface of the barrier drive gear 51. Further, as shown in FIG. 6(f), the winding portion of the barrier spring A55 is fitted concentrically with the pivot shaft of the barrier drive lever B57 and the barrier drive connecting plate 54, and as shown in FIG. The protrusion 54b of the barrier drive connecting plate 54 and the protrusion 57a of the barrier drive lever B57 at both ends 55a and 55b are charged as shown by the arrows.
and sandwich it.

When the release switch 5 is turned on, the motor 7 starts to rotate in reverse (Step 5301), and when the barrier drive gear 51 is rotated in the opposite direction (Step 5302), the barrier drive gear 51. Barrier drive lever A53, barrier drive connection plate 54
A crank mechanism between the two rotates the barrier drive connecting plate 54 in the opposite direction. Then, since the projections 57a and 54b are sandwiched between both ends 55a and 55b of the barrier spring A55, the barrier drive lever B57 also rotates in the same manner as the barrier drive connection plate 54, so that the lens barrier 58 is regulated by the barrier guide 59. 6(a) to 6(b), and a barrier open signal is output from the barrier state detection means 52 to the camera microcomputer 6, and the motor 7 is stopped. (Step 530
4). Further, by outputting this barrier open signal to the camera microcomputer 6, charge accumulation in the image sensor 25 is started (step 5305).

The time from the start to the end of charge accumulation is determined by the result of photometry by the photometer 80, and the camera microcomputer 6 controls the image sensor 25.

When the charge accumulation in the image sensor 25 is completed, the motor 7 starts to rotate in reverse again by the camera microcomputer 6 (step 53D6).
), the barrier drive gear 51 also rotates in the opposite direction again. Here again, the barrier drive gear 51, the barrier drive lever A
53, the barrier drive connection plate 54 is rotated in the forward direction by a crank mechanism between the barrier drive connection plate 54. Then, the barrier drive lever B57 is also rotated by the barrier spring A55 in the same way as the barrier drive connection plate 54, so the lens barrier 58 moves in the closing direction while being regulated by the barrier guide 59, and from FIG. 6(b) to FIG. When the barrier closes as shown in (a) and the barrier close signal is output by the barrier state detecting means 52 (step 5307), the motor 7 is stopped by the camera microcomputer 6 (step 930B).
).

When a force is applied from outside to open the lens barrier 58 while the lens barrier is closed, such as when a photographer tries to forcefully open the lens by hand, the operation is as shown in FIG. 6(c). There are two cases: a case where the barrier drive gear 51 and the planetary gear 10 are engaged, and a case where the barrier drive gear 51 and the planetary gear 10 are not engaged as shown in FIG. 6(d).

First, as shown in FIG. 6(c), when the barrier drive gear 5■ is meshed with the planetary gear 10, the gear connection is connected to the motor 7, so the barrier drive gear 51 does not rotate. , the barrier drive lever A53 and the barrier drive connection plate 54 also remain fixed. lens barrier 5
8 is opened by an external force, the position of the barrier drive lever B57 also changes due to the movement of the lens barrier 58. As a result, the barrier drive connecting plate 54 and the barrier drive lever B5
7 changes, barrier spring A55
The two are spring-coupled to prevent breakage.

In this state, the barrier spring A55, whose ends are locked to the pivot pin 54d and the protrusion 57a, is charged. Therefore, when the external force is removed, the lens drive lever B57 is returned to the closed position by the biasing forces of the barrier spring A55 and barrier spring B56, and the lens barrier 58 is also returned to the closed state.

On the other hand, when the barrier drive gear 51 and the planetary gear 12 are not engaged, as shown in FIG. The positions of the drive connection plate 54, barrier drive lever 33, and barrier drive gear 51 also change. Since the barrier spring B56 is charged by this external force, when the external force disappears, the lens drive lever B57 is returned to the closed position by the biasing force of the barrier spring 856, and thereby the lens barrier 58 is also closed, and the barrier The drive connection plate 54, barrier drive lever A53, and barrier drive gear 51 are also returned to the closed state.

The above operation is for the case where the photographer turns on the lens barrier 5 with a wide-angle lens, but when the photographer turns on the release switch 5 with a telephoto lens, the operation is as follows. That is, when the release switch 5 is turned on (step 5301), the camera microcomputer 6 reverses the motor 7 (step 5302), opens the lens barrier 58 (step S303), and after the end of exposure, the camera microcomputer 6 reverses the motor 7 again. The operations from closing the lens barrier 58 to closing the lens barrier 58 are exactly the same as when the release switch 5 is turned on in a wide-angle lens state (steps 5304 to 530B). At the time when the barrier state detection means 52 inputs the barrier close signal to the camera microcomputer 6, the signal from the lens state detection means 52 is a telephoto signal (step 5309), so the camera microcomputer 6 causes the motor 7 to rotate normally. (step 5311). The operations from this point on are similar to those in the case where the photographer stops operating the telephoto switch in the telephoto lens state described above, and the photographing lens returns to the wide-angle lens state.

Also, when the photographer turns on the release switch 5 with the close-up lens on, the camera microcomputer 6 reverses the motor 7 (step 5302) and closes the lens barrier 58. After the exposure is completed, the camera microcomputer 6 reverses the motor 7 again (step 5).
304 to 5306) and closing the lens barrier 58 (steps 5307 and 5808) are exactly the same as when the release switch 5 is turned on with the wide-angle lens in use. At the time when the barrier state detection means 52 manually inputs the barrier close signal to the camera microcomputer 6, the signal from the lens state detection means 52 is a close-up signal (steps 8309, 5310). Normal rotation begins (step 5311). The operations from this point on are similar to those performed when the photographer cancels the operation of the close-up switch while in the close-up lens state described above, and the photographing lens returns to the wide-angle lens state.

The operation of the lens barrier and photographic lens during photographing has been described above. However, at the time when the barrier state detecting means 52 outputs the barrier close signal, the lens state detecting means 12 outputs a signal other than the wide-angle signal (telephoto signal, close-up signal, close-up signal, etc.). signal, switching signal) is output (steps 5309, 531
0), the motor 7 is rotated forward by the camera microcomputer 6 (step 5311), and the photographing lens is rotated by the lens state detection means 1.
2 until the wide-angle signal is output (steps 5312 to 5314).

As described above, in the mechanism that performs each operation, the partially toothed gear 1101 as shown in FIG. 7(a) and ■! We have described the lens switching operation by the meshing of the gears 10 and 10.
If 1,102 has a tooth shape like that shown in Figure 7(a), the first tooth to collide with the other gear will be subject to an impact force, so it will need to be strong. It's coming. Therefore, it is safer to fill each gear 101, 102 as shown in FIG. 7(b).

That is, a built-up portion 101a as shown by the hatched portion is formed between the first tooth 101b and the second tooth 101c of the drive side gear 1101.

On the other hand, the built-up portion 10 of the driven gear I [102
The part corresponding to 1a, that is, the driven gear l1102
A notch 102d corresponding to the built-up portion 101a is formed at the tip of the second tooth 102c. Therefore,
When both gears 101 and 102 are engaged, the notch 10
2d and the built-up part 101a are engaged so that they face each other, no load is applied to the engagement, and the drive side gear Tl
The first tooth 101b of 0I can mesh with the second tooth 102c of the driven gear 102 without any force. Also, the seventh
The first tooth 102b of the driven gear l1102 in figure (b)
The second tooth of! On the opposite side from 02c, there is a built-up part 10 with some freedom as shown in the shaded part so as not to interfere with other mechanical parts.
It is also possible to form 2a.

This portion does not mesh with the first tooth 101b of the drive side gear 1101. In this way, the built-up parts 101a, 1
By forming 02a on each gear 101, 102,
The driving gear 1101 to which impact force is applied and the driven gear I [
It becomes possible to provide sufficient strength to each of the first teeth 101b, IO, 2b of 102.

Next, a viewfinder switching operation that is performed simultaneously with the lens switching operation described above will be described. The finder optical system is in the standard state when the photographing lens is a telephoto lens, and when the photographing optical system is in the wide-angle lens state, the wide-angle lens sub-optical system block 4I is located on the object side of the finder main optical system. Further, when the photographing optical system is used for close-up, a wedge lens block 45 is inserted on the subject side of the finder main optical system to reduce vararax. The operation will be explained below.

FIGS. 8(a) to (f) are diagrams showing the viewfinder switching operation in three states of the photographic lens. FIGS. 8(a) and (b) are in the wide-angle lens state, and c)
(d) shows the state of the telephoto lens, and Fig. 8 (e) and (D show the state of the close-up lens. For simplicity, Fig. 8 (a), (c), (e) represents the operation of the front lens block I and the wide-angle lens sub-optical system block 41.
Further, FIGS. 8(b), 8(d), and CD show the operation of the rear block 2 and the wedge lens block 45. FIGS. 8(g) to 8(i) show a mechanism for performing the above switching operation.

In the figure, the cylindrical portion 41a of the wide-angle con sub-optical system block 41 is coaxially connected with the cylindrical portion 45a of the wedge lens block 45, the cylindrical portion 42b of the wide-angle con gear 42, and the cylindrical portion 46a of the wedge gear 46. . The wide-angle con spring 43 and the wedge spring 47 are connected to the wide-angle con sub-optical system block 41 and the wedge lens block 45.
is located between. Wide angle conspring 43 above
As shown in FIG. 8(h), the winding part is fitted into the cylindrical part 41a of the wide-angle lens auxiliary optical system block 41, and both ends 43a and 43b are charged in the direction of the arrow, and the wire is inserted between them. The protrusion 41b of the wide-angle lens sub-optical system block 41
and the protrusion 42a of the wide-angle con gear 42.

Further, as shown in FIG. 8(i), the wedge spring 47 has its winding portion fitted into the circle m portion 45a of the wedge lens block 45, and both ends 47a and 47b are charged in the direction of the arrow. Then, between the protrusion 45b of the wedge lens block 45 and the protrusion 46a of the wedge gear 46,
It is sandwiched between.

First, the operation of the wide-angle lens sub-optical system block 41 will be explained. When the front lens block 1 is in the position shown in FIG. 8(a), the gear part 1e of the front lens block 1 and the wide-angle con gear 42 are engaged, and the wide-angle con sub-optical system block 41 and the wide-angle con gear 42 are in mesh with each other. Since the wide-angle constructor p<-A (44a) is connected with a spring by the wide-angle conspring 43, the consub-optical system 4■ is pressed and fixed to the wide-angle constructor p<-A (44a) when the wide-angle constructor p<-A (44a) is in a charged state. .

When the front lens block l rotates in this state, the gear part 1e of the front lens block 1 and the wide-angle con gear 42 are initially engaged, so the wide-angle con gear 42 rotates, but the gear part 1e of the front lens block 1 When the teeth finish meshing, the last gear of the wide-angle con gear 42 maintains its rotated position without moving backwards by sliding along the cam part 1'' of the front lens block l, and as shown in FIG.
) and (e), the front lens block 1 is pressed by the claw lh pressing one end of the wide-angle con gear 42, which charges the wide-angle con spring 43, and the wide-angle con spring 43 is charged. Con sub optical system block 4! is pressed and fixed to the wide-angle con stopper B (44b) and retracted out of the finder optical path (optical path center Y).

Next, the operation of the wedge lens block 45 will be explained. When the rear lens block 2 is in the position shown in FIGS. 8(b) and 8(d), the same condition as in the state of the wide-angle lens sub-optical system block 41 shown in FIGS. 8(c) and 8(e) is performed. The mechanism presses one end of the wedge gear 46 with the pressing pawl 2h of the rear lens block 2, thereby charging the wedge spring 47 and pushing the wedge lens block 4.
5 is suppressed and fixed to Fusabistra t<-B (48b),
It is moved out of the viewfinder optical path. Then, when the rear lens block 2 rotates, the first tooth of the wedge gear 46 slides along the cam part 2f of the rear lens block 2, starts meshing from the first tooth of the gear part 2e of the rear lens block 2, and the wedge gear 46 slides along the cam part 2f of the rear lens block 2. With the last tooth of 46 engaged with the gear part 2e of the rear lens block 2, press the wedge lens block 45 against the wedge stopper A (48a) by the charge of the wedge spring 47, insert it into the finder optical path, and position it. I try to do it.

In this example, a wedge lens is used to correct vararax in the close-up lens condition.
A similar effect can be obtained by inserting another field frame into the finder optical path instead of the wedge lens.

With only the lens switching mechanism as explained above, the lens switching gear All and the lens switching gear BI are
Since there is no gear connection between the front lens block I and the rear lens block 2, the positions of the front lens block I and the rear lens block 2 are maintained only by the pressing force of the snap springs A16 and B17, respectively, and there is no impact load on the camera. It is conceivable that if this happens, it will switch to another state.

Therefore, in this embodiment, in order to prevent switching of the photographic lens due to external force, the switching prevention claw A1B shown in FIG.
and a switching prevention claw B20. The operation of this switching prevention pawl A18 will be described below as an example.

The switching prevention pawl AI8 is rotatably supported on the rotating shaft A (18a) as shown in FIG.
), as shown in (b), the front lens block l and the rear lens block 2 are maintained in a retracted position where they cannot be prevented from rotating. Note that the rear lens block 2 is not shown for simplicity.

When at least one of the front lens block 1 and the rear lens block 2 is at the 0° position, the front lens block 1 and the rear lens block 2 are rotated in the forward direction when the lens is a wide-angle lens or a telephoto lens. Assuming that an inertial force due to an external force acts on the block 1.2, as shown in FIG. Center of gravity 1g and lens rotation axis 2 when block I is at 0゛ position
Since the weight balance is adjusted so that the straight line Z connecting the two is substantially parallel, an inertial force that causes the switching prevention claw A18 to rotate in the forward direction also acts on the switching prevention claw A18. The amount of pressing force on the switching prevention pawl A18 by the switching prevention spring A19, the amount of pressing force on the lens front block 1 due to the snap spring AI6, and the amount of pressing force on the rear lens block 2 due to the snap spring B17 are the same as that of the switching prevention pawl A1B and the front lens block 1. , is set almost equal to the weight ratio of the rear lens block 2, so when an inertial force that causes the front lens block l and the rear lens block 2 to start rotating is applied, the switching prevention claw A1B also rotates, and the switching prevention claw A18 enters into the rotation locus of the front lens block 1 and the rear lens block 2, and the claw portions 1 i provided on both lens blocks 1°2,
2 i (see Fig. 8(b)), the rotation of both lens blocks 1.2 is prevented (see Fig. 9(c)
)reference).

This inertial force is instantaneous, and when this inertial force disappears, the switching prevention claw A18, the lens front block l, and the lens rear block 2 are activated by the switching prevention spring A19, the snap spring A16, and the snap spring B17.
is returned to its normal position (see FIG. 9(a)).

The switching prevention claw B20 shown in FIG. 9(e) also has the front lens block 11, rear lens block 2, center of gravity, axis of rotation, and spring force set in the same way as the switching prevention claw A18. , operates in the same way as the switching prevention claw A1B (FIGS. 9(b) and 9(d)). In addition, in the figure, Z3 is a straight line connecting the center of gravity of the switching prevention claw B20 and the rotating shaft 20a, and 1 j and 2 j (see FIG. 8(b)) are the claw parts on which the switching prevention claw B20 is caught.

Furthermore, in this embodiment, an inertial force is applied due to an external force during the lens switching operation, and the switching prevention claw AI8 and the switching prevention claw B2
If the lens locks the front lens block 1 and the rear lens block 2, the motor and gear train may be destroyed as the motor 7 continues to rotate. A sliding mechanism is provided to prevent the gear train from being destroyed.

Furthermore, in this embodiment, the photographing lens system is divided into a front lens block 1 and a rear lens block 2, each of which operates independently, so there is a risk of stray light entering the photographing optical path.

For this reason, as shown in FIG. 10, the front lens block 1 and the rear lens block 2 are provided with stray light prevention walls projecting in an arc shape to block stray light. That is, the surface H+ of the front lens block l facing the rear lens block 2
(See FIG. 4(a)), an annular first stray light prevention wall 1k surrounding the main optical system 1a is formed to protrude along the front-rear direction, and the first stray light prevention wall 1 protects the rear lens block 2. Two second stray light prevention walls IL1m extending in an arc shape around the rotation axis are formed to protrude along the front-rear direction. Further, on the surface H of the rear lens block 2 facing the front lens block 1 (see FIG. 4(a)), a third annular stray light prevention wall 2k surrounding the sub optical system 2C is made to protrude along the front-rear direction. In addition to this, a fourth stray light preventing wall 2Q is formed to protrude along the front-rear direction and extends from the third stray light preventing wall 2 and always closes the space between the two second stray light preventing walls 112, 2m. By providing such a stray light prevention wall, even when the sub optical system 2c is retracted from the imaging surface side of the main optical system 1a etc. due to the rotation of the lens rear block 2, the fourth stray light prevention wall 2ρ is Second stray light prevention wall 1f2. In
Since the gap is closed, stray light can be effectively prevented from entering the camera. Therefore, stray light can be prevented in each state of the wide-angle lens (Fig. 10 (a)), telephoto lens (Fig. 10 (b)), and close-up lens (Fig. 10 (C)), and even during switching. can.

According to the above embodiment, when the barrier drive lever A53 as the first lever is driven by the drive of the motor 7, the barrier drive lever A53 is connected to the barrier spring A55 as the first spring member. The barrier drive lever B57 as a second lever is driven, and the lens barrier 58 moves according to the biasing force of the barrier spring 856 or against the biasing force of the barrier spring B56, and the lens barrier 58 moves to the optical system. Performs opening and closing operations against the When the lens barrier 58 is in the position where it closes the optical path of the optical system, that is, in the lens barrier closed position, an external force acts on the lens barrier 58 due to an erroneous operation of the lens barrier 58, causing the lens barrier 58 to change from the closed position to the open position. When you move the optical system to a position that opens the optical path,
The barrier drive lever B together with the lens barrier 58
57 moves against the biasing force of the barrier spring B5B. In this case, the biasing force of the barrier spring A55 connecting the levers A53 and 857 only increases, and the barrier drive lever A53 is not driven. Therefore, since the barrier drive lever A53 connected to the motor 7 is not driven, the connection portion between the motor 7 and the barrier drive lever A53 is not affected by the external force, and damage to the connection portion is not effective. is prevented. Further, when the external force is removed from the lens barrier 58, the biasing force of the barrier spring 85B acts on the barrier drive lever B57 connected to the lens barrier 58, so that the barrier spring B56 is biased. The force drives the barrier drive lever B57, and the lens barrier 58 can be reliably moved to its original closed position.

Note that the present invention is not limited to the above embodiments,
It can be implemented in various other ways. For example, various spring members can be used as the barrier spring as long as they perform the same actions as described above.

[Brief explanation of drawings]

1(a) to 1(e) are a plan view, a front view, a bottom view, a left side view, a right side view, and a top view, respectively, of an electronic still camera equipped with a lens barrier safety mechanism according to an embodiment of the present invention. FIG. 1(f) is an explanatory diagram showing the drive system provided in the still camera, FIGS. 2(a) to (C) are explanatory diagrams showing the states of the wide-angle lens, telephoto lens, and close-up lens, respectively. The figure shows the distance that can be photographed with each lens and the screen ratio when photographing a person. Figure 4 (a) is a sectional view of the main part showing the lens switching drive mechanism, and Figures 4 (b) and (d). ,
(f), (h), (D, (1) are explanatory diagrams showing the operation of the front lens block, respectively, Fig. 4 (c), (e), (g),
(i), (k), and (m) are explanatory diagrams showing the operation of the rear lens block, respectively, FIG. 5(a) is a pattern diagram of the pattern board of the lens state detection means, and FIG. 5(b) is the above-mentioned pattern. A timing chart diagram showing signals generated by the substrate and a section, Figures 6(a) to 6(d) are explanatory diagrams showing the barrier opening/closing operation, respectively, and Figures 6(e) to (g) are respectively explanations of the barrier opening/closing mechanism. Figure 7(a). 8(b) is a front view of a partially toothed gear and a front view of a case where a built-up portion is formed on the gear, FIGS. 8(a) and 8(b) are respectively explanatory diagrams of finder switching operation in a wide-angle lens,
FIGS. 8(c) and 8(d) are illustrations of the finder switching operation in a telephoto lens, respectively, FIGS. 8(e) and (D are illustrations of the finder switching operation in a close-up lens, respectively, and FIG. 8(g) ) to (i) are explanatory diagrams of the mechanism that performs the finder switching operation, FIGS. 9(a) to (d) are explanatory diagrams of the operation of the switching prevention mechanism, respectively, and FIG. 9(e) is an explanatory diagram of the switching prevention mechanism. A perspective view showing the installation state, Fig. 10 (
a) to (c) are explanatory diagrams showing the stray light blocking mechanism, respectively.
2(a) and 2(b) are flowcharts of the lens switching operation, and FIG. 2(c) is a flowchart of the barrier opening/closing operation. ■... Lens front block, 1 a, 1 b... Main optical system, lk, 19, 1 m... Stray light prevention wall, 2...
Rear lens block, 2c...Sub-optical system, 2k, 2
12... Stray light prevention wall, 3... Telephoto switch, 4...
・Close-up switch, 5.・Release switch,
6... Camera microcomputer, 7... Motor, 8... Reduction gear, 9... Sun gear, 10... Planetary gear, 11
... Lens switching gear A112... Lens state detection means, 13... Lens switching gear B, 14... Lens switching gear C, 15... Lens switching gear C', 16...
Snap spring A, 17...Snap spring B118...Switching prevention claw A119...Switching prevention spring A120...Switching prevention claw B, 21...Switching prevention spring B, 22...Lens rotation shaft, 23...
Lens positioning A, 24...Lens positioning B125
...Image sensor, 40...Part of viewfinder, 41...
・Wide-angle con sub optical system block, 42... Wide-angle con gear, 43... Wide-angle con spring, 44... Wide-angle con stopper, 45... Wedge lens block, 46.
...Wedge gear, 47...Wedge spring, 48.
... Wedge stopper, 51 ... Barrier drive gear, 5
2...Barrier state detection means, 53...Barrier drive lever, 54...Barrier drive connection plate, 55...Barrier spring A156...Barrier spring B157...
・Barrier drive lever B158...Lens barrier, 59
...Barrier guide, 70...Flash, 71...
・DC power supply, 8o...Photometering section, 90...Main switch, 101...Drive side gears 1.101a, 102a
- Filling part, 101b. 102b...first tooth, lOlc, 102c mountain second tooth, 102...driven side gear ■, 102d...notch portion. Patent Applicant Minolta Camera Co., Ltd. Agent Patent Attorney Maeda Ao and 2 others Figure 1 (0) Figure 1 (C) Figure 1 (bl Figure (d) Figure (el) Figure 4 (bl Figure 4) Figure + c + Figure 4 (fl Figure 4 (91 Section 4 Tdl Figure 4 (h) Figure 4 fil Figure 44 fjl Figure 4 (kl Figure 4 (J) Figure 4 fm (m) Figure 6 ( b) Figure 6 (C) Figure 6 (d) aE B rXI (o) Broom 8 Figure (b) 2# Figure 8 (C) Figure 8 (d) Figure 8 (9)

Claims (3)

[Claims] (1) A drive source (7) for driving the lens barrier (58) to open and close with respect to the optical system; and a first lever connected to and driven by the drive source (7).
53), which is connected to the first lever (53) by a first spring member (55) and is always urged in a predetermined direction by a second spring member (56), and the lens barrier (58).
A safety mechanism for a lens barrier, comprising: a second lever (57) to which the lens barrier is connected. (2) The predetermined direction in which the second spring member (56) is always biased is a direction in which the lens barrier (58) is moved to a lens barrier closed position that closes the optical path of the optical system. Lens barrier safety mechanism described in . (3) The lens barrier safety mechanism according to claim 1, wherein the biasing force of the first spring member (55) is greater than the biasing force of the second spring member (56).