JP2006018144A - Lens cover unit and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens cover unit capable of surely and stably holding a lens cover in either of an open state or a closed state. <P>SOLUTION: Regarding the lens cover unit where the lens cover is opened/closed in front of an imaging lens, at least either of the open state or the closed state of the lens cover is held by magnetic force. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lens cover unit in which a lens cover is opened and closed in front of an imaging lens, and an imaging apparatus including the lens cover unit.

  Conventionally, in digital cameras and cameras using silver halide film, a lens cover that opens and closes in front of the imaging lens has been placed to prevent dust from adhering to the imaging lens and from being soiled by touching the fingertip. To be done.

  The lens cover is often composed of two or four, and engages with a rotating ring that rotates in conjunction with the advance and retreat of the lens barrel that holds the imaging lens. Rotate around an axis. When the imaging device is not used, that is, when the lens barrel is retracted, the side walls located inside the two lens covers are in contact with each other to be closed to protect the imaging lens, and when the imaging device is used. That is, when the lens barrel is extended, each lens cover is retracted from the incident optical path to the imaging lens and a predetermined opening to be opened.

As an example, there is a camera that opens and closes a lens cover by a driving force generated by an electric driving means that moves a lens barrel (see Patent Document 1).
Japanese Patent Laid-Open No. 8-271952

  As described above, since the lens cover is opened and closed in conjunction with a large number of components, an error is likely to occur depending on the component accuracy, and the lens cover may not be sufficiently closed or opened. If the lens cover is not sufficiently closed, there arises a problem that dust enters from the gap between the two lens covers even during non-photographing, and the appearance is unsightly. On the other hand, if the lens cover is not sufficiently opened, there arises a serious problem that a part of the optical path incident on the imaging lens is shielded at the time of shooting, and it is retracted from the predetermined opening without shielding the optical path. Otherwise, it is unsightly in appearance.

  In addition, in order to reliably operate the lens cover, a spring is applied to the rotating ring that rotates while being engaged with the lens cover so as to bias the lens cover in one direction. A configuration in which the rotating ring rotates according to the cam provided on the imaging device side is widely used. However, if the imaging lens is a zoom lens, the amount of extension of the lens barrel is large, so that the rotating ring rotates in the retracted or wide-angle state. Even if the ring and the cam are engaged, when the telephoto state is reached, the rotating ring is separated from the cam and is fed out together with the lens barrel. For this purpose, a spring is applied to the rotating ring so as to urge the lens cover in the opening direction. In the retracted state, the lens cover is closed against the spring, but when the lens barrel is extended, the spring is rotated by the spring. The lens cover is kept open even if the rotating ring is separated from the cam.

  However, if the lens cover is urged in the opening direction, the unstable and unstable state cannot be resolved in the closed state even if the lens cover is stable in the opened state.

  In addition, when the imaging lens is a single focus lens that is not a zoom lens, it is possible to bias the rotating ring in the closing direction of the lens cover. A stable state cannot be resolved.

  Thus, since it is difficult to urge both the closed state and the open state, even if one is stabilized, the uncertain and unstable state of the other cannot be resolved.

  It is possible to envisage energizing both the closed state and the open state using a tumbler spring that can be energized on both sides, but the tumbler spring requires a large gap for movement. Therefore, it is very difficult to put it to practical use in an imaging apparatus such as a camera that is required to be downsized.

  The present invention has been made in view of such a problem, and provides a lens cover unit that can reliably and stably hold at least one of an open state and a closed state of a lens cover, and an imaging device including the lens cover unit. The purpose is to propose.

  The above object is achieved by the following means.

  A lens cover unit in which a lens cover is opened and closed in front of an imaging lens, wherein at least one of an open state and a closed state of the lens cover is held by a magnetic force.

  According to the lens cover unit and the imaging apparatus of the present invention, when the lens cover is in an open state or at least a closed state, the state is held by magnetic force, so that expensive high-precision parts are not used. However, the lens cover is not sufficiently closed or opened due to an error in component accuracy. Therefore, there is no problem that dust does not enter from the gap between the two lens covers due to the lens cover not being sufficiently closed, and the appearance is not unsightly. In addition, if the lens cover is not sufficiently opened, there is a serious problem that a part of the optical path incident on the imaging lens is shielded, and the lens cover is not retracted from the predetermined opening without shielding the optical path. There is no such thing as unsightly appearance.

  A lens cover unit according to an embodiment of the present invention will be described in detail with reference to FIGS.

  FIG. 1 is a diagram of a lens cover unit when the lens cover is opened as viewed from the imaging lens side, FIG. 2 is a diagram of the lens cover unit when the lens cover is closed as viewed from the imaging lens side, and FIG. 3A is a view of the lens cover in an open state, FIG. 3B is a view of the lens cover in a closed state, FIG. 4 is a view of only a rotating ring, FIG. 5 is a view of only a holding plate, FIG. 6 is a diagram showing the engaged state of the cam pin and the cam groove, FIG. 7 is a diagram of the click mechanism, and FIG. 8 is a diagram in which a magnet is embedded.

  1 and 2, reference numeral 1 denotes a substrate that holds each member constituting the lens cover unit. On the substrate 1, two lens covers 2, 3, a rotating ring 4, and two holding plates 5 are sequentially arranged. , 6 are installed.

  3 to 5, the lens cover 2 is pivotally supported on the substrate 1 by a stepped pin 7 inserted into the shaft hole 2a, and the lens cover 3 has a shaft hole. It is pivotally supported by the board | substrate 1 by the stepped pin 8 inserted in 3a. The rotating ring 4 can be rotated by being guided by a plurality of ribs 1 a provided in the vicinity of the outer peripheral edge of the substrate 1, and the rotating ring 4 is fixed to the substrate 1 by stepped pins 9 and 10. The holding plates 5 and 6 prevent upward slipping.

  Here, two pins 4 b and 4 c protrude from the back surface of the rotating ring 4, the pin 4 b is inserted into the long hole 2 b provided in the lens cover 2, and the pin 4 c is inserted into the long hole 3 b provided in the lens cover 3. Has been.

  Accordingly, when the rotating ring 4 rotates counterclockwise from the opened state shown in FIG. 1, the two pins 4b and 4c also rotate counterclockwise, so that the lens cover 2 rotates clockwise by the long hole 2b, Similarly, the lens cover 3 is also rotated clockwise by the long hole 3b. Therefore, the closed state shown in FIG. 2 is established, and the inner side wall 2c of the lens cover 2 and the inner side wall 3c of the lens cover 3 come into contact with each other, so that the optical image of the subject is transmitted and guided to the imaging lens. The opening 1b provided in the center is closed.

  On the other hand, when the rotating ring 4 rotates clockwise from the closed state shown in FIG. 2, the two pins 4b and 4c also rotate clockwise, so that the lens cover 2 rotates counterclockwise by the long hole 2b. The lens cover 3 is also rotated counterclockwise by the hole 3b. Accordingly, the open state shown in FIG. 1 is established, and the side wall 2c of the lens cover 2 and the side wall 3c of the lens cover 3 are retracted from the opening 1b provided at the center of the substrate 1, respectively.

  The above is the basic configuration of the operation of the lens cover. More specifically, the rotating ring 4 has an imaging lens (not shown) and an arm shown in FIG. The portion 4d extends, and a cam pin 4e is erected at the tip of the arm portion 4d. The lens cover unit is fixed to a lens barrel that holds the imaging lens, and a cam plate 11 is fixed to the lens barrel, and a cam pin 4 e is engaged with a cam groove 11 a provided in the cam plate 11. When the lens barrel is retracted at the time of non-photographing, the lens cover unit is also located on the image pickup apparatus main body side, and the cam pin 4e is at the position C. However, at the time of shooting, the lens cover unit is extended together with the lens barrel, and the cam pin 4e moves to the W position. Accordingly, since the cam pin 4e moves to the right, the rotating ring 4 rotates clockwise, and the lens covers 2 and 3 are opened as described above.

  On the other hand, when the lens barrel is retracted from the shooting state, the lens cover unit is also retracted, and the cam pin 4e moves to the position C. Accordingly, since the cam pin 4e moves to the left, the rotating ring 4 rotates counterclockwise, and the lens covers 2 and 3 are closed as described above.

  When the imaging lens is a single focus lens, the amount of extension from the retracted state is small, so that the cam pin 4e only needs to move from the position C to the position W shown in FIG. However, when the imaging lens is a zoom lens, the amount of extension from the retracted state to the telephoto state becomes very large, and the cam pin 4e is engaged with the cam groove 12a at the W position in the wide angle state. In the telephoto state, it is further extended and moved to a position, for example, T, and the cam pin 4e comes off the cam groove 12a.

  As described above, the lens covers 2 and 3 are in the open state, but when the cam ring 4e is detached from the cam groove 12a and vibration or impact is applied and the rotating ring 4 rotates counterclockwise, the cam pin 4e. The position of moves from the position of T to the left. As a result, there arises a problem that the cam pin 4e cannot be engaged with the cam groove 12a when trying to retract the lens cover unit together with the lens barrel in order to make the imaging lens in a wide angle state or in a retracted state. .

  Therefore, a click mechanism as shown in FIG. 7 is provided so that the rotating ring 4 does not rotate carelessly when the lens covers 2 and 3 are opened. That is, the protrusion 5 a is provided on the back surface of the holding plate 5, and the crest 4 f is formed on the rotating ring 4. When the lens covers 2 and 3 are in the open state, the crest 4f of the rotating ring 4 is located to the right of the protrusion 5a of the holding plate 5 as shown in FIG. Does not easily rotate to the left, ie in the closing direction. The rotating ring 4 is restricted by a stopper (not shown) so as not to rotate further to the right from the state shown.

  On the other hand, when the lens covers 2 and 3 are in the closed state, as shown in FIG. 7B, the crest 4f of the rotating ring 4 is located on the left side of the protrusion 5a of the holding plate 5, so that the rotating ring 4 Does not easily rotate to the right, that is, in the opening direction.

  Instead of providing such a click mechanism, a spring may be applied between the rotating ring 4 and the substrate 1 to bias the rotating ring 4 in the clockwise direction.

  In the lens cover unit configured as described above, the lens covers 2 and 3 have the shaft hole 2a and the tip end portion despite the short distance between the shaft hole 2a and the long hole 2b and the distance between the shaft hole 3a and the long hole 3b. The interval between 2d and the interval between the shaft hole 3a and the tip portion 3d are long. Thereby, the open state and the closed state of the lens covers 2 and 3 are affected by the backlash between the long hole 2b of the lens cover 2 and the pin 4b of the rotating ring 4, and the lens cover 3 and the long hole 3b are rotated. It is affected by the looseness of engagement with the pin 4c of the ring 4. Further, the open and closed states of the lens covers 2 and 3 are determined by the backlash between the shaft hole 2a of the lens cover 2 and the stepped pin 7, and the fit between the shaft hole 3a of the lens cover 3 and the stepped pin 8. Also affected by play. Further, the position of the rotating ring 4 is affected by the backlash of the cam pin 4e and the cam groove 12a.

  Therefore, in order to ensure the open state and the closed state of the lens covers 2 and 3 only by the component accuracy, it is necessary to use highly accurate components, resulting in an expensive lens cover unit. In addition, when parts with normal accuracy are used, they are not surely opened or closed. If the lens covers 2 and 3 are not sufficiently opened, there arises a serious problem that a part of the optical path incident on the imaging lens is shielded at the time of photographing, and the lens 1 is retracted from the opening 1b without shielding the optical path. Otherwise, it is unsightly in appearance. On the other hand, if the lens covers 2 and 3 are not sufficiently closed, there is a problem that dust enters from the gap between the lens covers 2 and 3 even during non-photographing, and the appearance is unsightly. In addition, even if the lens covers 2 and 3 are apparently closed or open, if they are unstable, the position is displaced and the above-described problems occur when vibrations or impacts are applied.

  For this reason, it is conceivable to apply a spring to the rotating ring 4 and urge it as described above. However, when the imaging lens is a zoom lens, the cam pin 4e is separated from the cam groove 12a. The direction of force is the opening direction. Therefore, the above-mentioned problem cannot be dealt with in the closed state. If the cam pin 4e does not move away from the cam groove 12a, the rotating ring 4 may be urged in the closing direction. However, in this case, the above problem cannot be dealt with in the open state.

  Therefore, in the lens covers 2 and 3, magnets 21 and 31 are embedded in the vicinity of the side walls 2 c and 3 c that are located inside and abut against each other when the lens covers 2 and 3 are closed. As a result, the magnet 21 and the magnet 31 are attracted to each other by magnetic force, so that there is no gap between the closed lens covers 2 and 3 due to component accuracy and backlash, and the closed state of the lens covers 2 and 3 is reliably maintained. can do.

  In the lens covers 2 and 3, magnets 22 and 32 are embedded in the vicinity of the outer peripheral edge, and magnets 41 and 42 are also embedded in the vicinity of the outer peripheral edge of the substrate 1. As a result, the magnet 22 and the magnet 41 are attracted to each other by magnetic force, and the magnet 32 and the magnet 42 are attracted to each other by magnetic force. Therefore, the lens covers 2 and 3 cannot be completely retracted from the opening 1b due to component accuracy and backlash. Therefore, the open state of the lens covers 2 and 3 can be reliably held. In addition, although AA sectional drawing in FIG. 1 is shown in FIG. 8, although not shown in figure, the embedding state of the magnets 21, 31, 32, 42 is also the same.

  In some cases, only the magnets 21 and 31 may be provided, or only one of the magnets 22, 32, 41, and 42 may be provided.

  Further, instead of embedding the magnets 21, 22, 31, 32 in the lens covers 2, 3, the lens covers 2, 3 are each formed of a plastic magnet so that the entire lens covers 2, 3 are magnetized. Also good.

  Further, the substrate 1 may be formed of a plastic magnet and partially magnetized so that the open state of the lens covers 2 and 3 is maintained by the magnetic force of the substrate 1 and the lens covers 2 and 3.

  In addition, although different from the configuration shown in FIGS. 1 to 8, a magnet is embedded in a predetermined position of the substrate 1, or the substrate 1 is formed of a plastic magnet, and a magnet is formed in a predetermined position of the lens covers 2 and 3. Alternatively, the lens covers 2 and 3 may be formed of plastic magnets, and the closed state of the lens covers 2 and 3 may be maintained by the magnetic force of the substrate 1 and the lens covers 2 and 3.

  Further, the lens covers 2 and 3 may be formed of a thin iron plate and magnetized.

  Moreover, although the above structure was a structure with two lens covers, a one-sheet structure may be sufficient and a four-sheet structure may be sufficient.

  When the four lens covers are used, when the lens cover is closed, the two first lens covers whose inner side walls are in contact with each other are rotated by the rotation of the rotating ring in the same manner as in the two-lens configuration. , The two second lens covers located on the outside are pressed and forcibly rotated, and the opening of the substrate is closed by the four lens covers. On the other hand, at the time of opening, the two first lens covers are rotated in the same manner as in the two-lens configuration by rotating the rotating ring and retracted from the opening of the substrate, and the two second lens covers are rotated by rotating the first lens cover. The lens cover is pressed and forcibly rotated to retract.

It is the figure of the lens cover unit which looked at the state where the lens cover was opened from the imaging lens side. It is the figure of the lens cover unit which looked at the state where the lens cover was closed from the imaging lens side. It is a figure of only a lens cover. It is a figure of only a rotation ring. It is a figure of only a holding plate. It is a figure which shows the engagement state of a cam pin and a cam groove. It is a figure of a click mechanism. It is the figure which embedded the magnet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 1b Opening part 2,3 Lens cover 4 Rotating ring 5,6 Holding plate 21, 22, 31, 32, 41, 42 Magnet

Claims (8)

In the lens cover unit that opens and closes the lens cover in front of the imaging lens,
A lens cover unit that holds at least one of an open state and a closed state of the lens cover by a magnetic force. Magnets are embedded in the vicinity of the side walls which are located inside the two lens covers and come into contact with each other in the closed state, and the closed state of the lens cover is held by the magnetic force of both the magnets. The lens cover unit according to claim 1. 2. The lens cover unit according to claim 1, wherein the two lens covers are each formed of a plastic magnet, and the closed state of the lens cover is held by a magnetic force of both the lens covers. A magnet is embedded in the vicinity of the outer peripheral edge of the substrate that holds the lens cover, and a magnet is embedded in the vicinity of the outer peripheral edge of the lens cover, and the open state of the lens cover is held by the magnetic force of both the magnets. The lens cover unit according to claim 1. A magnet is embedded in the vicinity of the outer periphery of the substrate holding the lens cover, the lens cover is formed of a plastic magnet, and the open state of the lens cover is held by the magnetic force of the magnet and the magnetic force of the lens cover. The lens cover unit according to claim 1. The substrate for holding the lens cover and the lens cover are formed of a plastic magnet, and the open state of the lens cover is held by the magnetic force of the substrate and the lens cover. Lens cover unit. A magnet is embedded in a predetermined position of the substrate holding the lens cover, or the substrate is formed of a plastic magnet, and a magnet is embedded in a predetermined position of the lens cover, or the lens cover is formed of a plastic magnet. The lens cover unit according to claim 1, wherein the closed state of the lens cover is held by a magnetic force of the substrate and the lens cover. An imaging apparatus comprising the lens cover unit according to claim 1.

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