JP5430071B2 - Optical element holding mechanism and imaging apparatus - Google Patents

Description

  The present invention relates to an optical element holding mechanism and an imaging apparatus having the holding mechanism.

  FIG. 11 is a cross-sectional view showing an optical element holding mechanism in a conventional imaging apparatus. A CCD mask 102 having a mask function for cutting off harmful rays by limiting the amount of incident light is incorporated in the CCD base plate 101. The CCD mask 102 is made of a thin plate metal (sheet metal) or the like. An optical filter 103 is incorporated from the back surface of the CCD mask 102.

  The front surface of the optical filter 103 is held by the CCD mask 102, and the side surface thereof is held by a holding member 101 a provided on the CCD base plate 101. Further, a CCD rubber 104 made of an elastic member is incorporated on the back surface of the optical filter 103. A CCD holding member 105 that fixes the CCD 106 by bonding from the back surface of the CCD rubber 104 is incorporated.

  In the optical element holding mechanism having the above-described configuration, a plate shape having a thinner cross section than the resin member is used as a fixing member for fixing the optical filter 103 as compared with the case where the CCD mask is integrally formed with the CCD base plate which is a resin member. The CCD mask 102 which is a metallic member is used. Thereby, it is possible to reduce the thickness of the entire optical system in the optical axis direction.

In addition, various techniques for reducing the thickness in the optical axis direction (reducing the distance) have been proposed. The holding mechanism described in Patent Document 1 has a structure in which an optical filter is incorporated into an optical filter holding portion made of a metal sheet metal having two bent portions, and this optical filter holding portion is inserted from the back surface of the CCD base plate. Similarly, this holding mechanism has a structure in which a reduction in thickness in the optical axis direction is achieved by using a metal sheet metal instead of a resin member as the fixing member of the optical filter.
JP 2006-67356 A

  However, the conventional optical element holding mechanism has the following problems. That is, in the case of the above conventional former, as shown in FIG. 12, when the external size of the CCD 206 is larger than that of the optical filter 103, there is clearly no space for disposing the CCD rubber 104, and the configuration itself cannot be implemented. is there. FIG. 12 is a cross-sectional view showing a conventional holding mechanism for an optical element when the external size of the CCD is larger than that of the optical filter.

  In this case, the CCD rubber 104 can be disposed by molding the holding member 101 a of the CCD base plate 101 to a thickness substantially equal to that of the optical filter 103. However, as shown in FIG. 12, when the optical filter 103 is thin, reducing the thickness of the holding member 101a exceeds the molding limit of the resin. In addition, it is possible to make the optical filter 103 larger than the external size of the CCD 206 and adopt the conventional configuration, but such a configuration makes the size of the optical filter 103 uselessly larger than the optically required size. Become. Therefore, there is a problem that the manufacturing cost becomes high.

  On the other hand, in the case of the above-mentioned conventional latter (Patent Document 1), the optical filter holding portion has a stepped complicated shape with two-step bending. For this reason, there was a problem that the position on the optical axis of the optical filter could not be determined due to the corresponding manufacturing error. For this reason, it is necessary to provide a design gap for the lens at the front stage of the optical filter in consideration of the manufacturing error, and there is a problem that the thickness of the optical system in the optical axis direction cannot be reduced accordingly. It was.

  Therefore, the present invention provides an optical element holding mechanism that realizes thinning in the optical axis direction while suppressing manufacturing errors even when the outer size of the image sensor is larger than the outer size of the optical element or when the optical element is thin. An object is to provide an imaging apparatus having a holding mechanism.

To achieve the above object, the holding mechanism of the optical element of the present invention, the holding mechanism of the optical element that will be disposed on a plane perpendicular to the Oite optical axis in front of the image pickup device, perpendicular to the optical axis plane A regulating member that is disposed inside and regulates the position of the optical element in the optical axis direction, and holds the optical element on the outer circumferential side surface of the optical element and holds the regulating member on the outer circumferential end surface of the regulating member and an imaging unit holding member holding member is al provided, the optical by part of the outer peripheral edge surface of a part and the regulating member of the outer peripheral side surface of the optical element is held at the same end face of the optical element holding member The position of the element and the restricting member in a plane orthogonal to the optical axis is restricted .

An imaging apparatus according to the present invention includes the optical element holding mechanism according to any one of claims 1 to 3 .

According to the holding mechanism of the optical element according to the present invention, the outer size of an imaging device even when the case outer size larger than or optical elements of the optical element is thin, by suppressing the production error to realize reduction in thickness of the optical axis be able to.

According to the optical element holding mechanism according to the present invention , the optical element holding member holds the optical element and restricts the position of the restricting member in the plane orthogonal to the optical axis. It is not necessary to provide. Further, by positioning the optical element and the regulating member in the plane orthogonal to the optical axis with the same member, the outer size of the optical element with respect to the opening of the regulating member can be optimized.

  DESCRIPTION OF EMBODIMENTS Embodiments of an optical element holding mechanism and an imaging apparatus according to the present invention will be described with reference to the drawings. The imaging apparatus of this embodiment is applied to a digital camera having a zoom lens barrel.

  FIG. 1 is a perspective view showing an appearance of the digital camera 62 in a state where the power is turned off in the embodiment. FIG. 2 is a perspective view showing an appearance of the digital camera 62 in a state where the power is turned on. A front view of the digital camera 62 is provided with a finder 67 for determining the composition of the subject, an auxiliary light source 66 for assisting the light source when performing photometry / ranging, a strobe 68, and a zoom lens barrel 71.

  A release button 63, a power switch button 65, and a zoom switch 64 are arranged on the top surface of the digital camera 62. Further, a tripod mounting portion (not shown) and a card battery cover (not shown) are disposed on the bottom surface of the digital camera 62.

  On the back of the digital camera 62, operation buttons (not shown) for switching various functions, a display (not shown) made of an LCD, and a viewfinder eyepiece (not shown) are arranged. . By pressing the operation button, an operation mode of the digital camera 62, for example, a shooting mode, a playback mode, a moving image shooting mode, or the like is selected. The display displays the image data stored in the memory or the image data read from the memory card on the screen. When the playback mode is selected, the display reduces a plurality of pieces of shooting data and displays them on the screen.

  Next, the overall configuration of the zoom lens barrel 71 will be described. FIG. 3 is a cross-sectional view showing the structure of the zoom lens barrel 71 in the housed state. FIG. 4 is a cross-sectional view showing the structure of the zoom lens barrel 71 in the photographing enabled state.

  The zoom lens barrel 71 includes an entrance of impurities such as dust into the first group lens 1 and the second group lens 2 that perform zooming, the third group lens 3 that controls focus and image plane correction, the CCD 4, the optical filter 5, and the CCD 4. CCD rubber 6 for preventing The optical filter 5 is a known infrared cut filter or low-pass filter. The CCD 4 converts the optical image into an electrical signal.

  The zoom lens barrel 71 includes a first group barrel 11, a second group barrel 12, and a third group barrel 13 that hold the first, second, and third group lenses (lens groups) movably in the optical axis direction. And a moving cam ring 21. The first group barrel 11 and the second group barrel 12 are held by a movable cam ring 21 having a cam groove formed on the inner periphery.

  The zoom lens barrel 71 includes a fixed barrel 22, a CCD holder 23, a CCD holding portion 7, a drive ring 24, a rectilinear guide ring 25, and a cover cylinder 26. The fixed cylinder 22 movably holds the movable cam ring 21 with a cam groove formed on the inner periphery. The CCD holder 23 (imaging unit holding member) holds the CCD holding unit 7 that fixes the optical filter 5 and the CCD 4 by bonding. The drive ring 24 rotates the moving cam ring 21. The rectilinear guide ring 25 suppresses the rotation of the first group barrel 11 and the second group barrel 12 and guides the rectilinear movement thereof. The cover tube 26 is fixed to the CCD holder 23 together with the fixed tube 22 and restricts the movement of the drive ring 24 in the optical axis direction.

  The operation of the zoom lens barrel 71 having the above structure will be described. A zoom gear system (not shown) meshes with an outer peripheral gear (not shown) provided on the drive ring 24 to rotate the drive ring 24. The front end portion of the drive ring 24 abuts on the flange portion 26 a of the cover cylinder 26, and the rear end portion abuts on a flange portion 22 c formed on the rear end portion of the fixed cylinder 22. Thereby, the movement of the drive ring 24 in the optical axis direction is restricted.

  On the outer periphery of the movable cam ring 21, three follower pins 21 a that are respectively fitted with three cam grooves 22 a formed on the inner surface of the fixed cylinder 22 are provided. The follower pin 21a moves along the cam groove 22a of the fixed barrel 22 in accordance with the rotation of the movable cam ring 21, whereby the movable cam ring 21 moves in the optical axis direction.

  A drive pin 21 b is provided on the outer periphery of the movable cam ring 21. The drive pin 21b is formed on the side surface of the fixed cylinder 22, passes through the three guide grooves 22b penetrating in the thickness direction, and is a straight guide groove (not shown) formed in the drive ring 24 in the optical axis direction. ) And slidably fitted.

  When the drive ring 24 rotates, the rotation is transmitted to the moving cam ring 21 through the drive pin 21b fitted in the straight guide groove, and the moving cam ring 21 rotates along the cam groove 22a of the fixed cylinder 22 while rotating the optical axis. Will move in the direction.

  The rectilinear guide ring 25 is rotatable relative to the moving cam ring 21 and is supported by the moving cam ring 21 so as to restrict relative movement in the optical axis direction. Further, the rear protrusion 25 a on the outer peripheral portion of the rectilinear guide ring 25 is fitted to a rectilinear guide formed on the inner peripheral side surface of the fixed cylinder 22 so as to be able to advance straight. Thereby, the movement of the rectilinear guide ring 25 in the rotational direction is restricted.

  As described above, when the movable cam ring 21 moves while rotating along the cam groove 22a of the fixed cylinder 22, the linear guide ring 25 follows the movement of the movable cam ring 21 in the optical axis direction only in the optical axis direction. Moving.

  The first group barrel 11 and the second group barrel 12 are held in the inner surface cam grooves 21c and 21d of the movable cam ring 21, respectively. A rectilinear guide groove for restricting the first group barrel 11 and the second group barrel 12 to travel straight is formed on the side surface of the rectilinear guide ring 25. The rotation movement of each group barrel is suppressed by the straight guide groove. As described above, when the movable cam ring 21 moves, each group lens barrel moves in the optical axis direction without rotating, and the lens can be disposed at a position corresponding to a desired focal length.

  The first lens barrel 11 is provided with a known lens barrier mechanism 11a, which blocks the optical path of the photographing optical system in the retracted state. A known diaphragm shutter unit is fixed to the second group barrel 12 and moves in the optical axis direction integrally with the second group barrel 12. The third group barrel 13 is slidably held by a main guide bar 31 and a sub guide bar (not shown) fixed to the CCD holder 23 in parallel with the optical axis. A nut (not shown) screwed into a feed screw of a focus motor (not shown) is held between the third group lens barrel 13 so that when the focus motor rotates, the third group lens barrel 13 becomes main. It advances and retreats along the guide bar 31 in the optical axis direction.

  Next, the holding mechanism of the optical filter 5 will be described in detail. FIG. 5 is an exploded perspective view showing the structure of the CCD unit viewed from the back. FIG. 6 is an exploded perspective view showing the structure of the CCD unit viewed from the front. FIG. 7 is a cross-sectional view showing a holding mechanism for the optical filter 5. FIG. 8 is a perspective view showing the shape of the CCD mask 8 viewed from the back. FIG. 9 is a front view showing the holding mechanism of the optical filter 5 with the CCD mask 8 attached. FIG. 10 is a view showing the holding mechanism of the optical filter 5 with the CCD mask 8 removed.

  This holding mechanism is configured to incorporate components from before and after the CCD holder 23. From the front of the CCD holder 23, the CCD mask 8 is incorporated into the mounting surface 23a. The CCD mask 8 has an opening 8a for limiting the amount of incident light and cutting harmful light. Here, the CCD mask 8 is provided with a snap fit portion 8b, and the CCD holder 23 is provided with a snap fit portion 23b. When assembling, the CCD mask 8 is fixed to the CCD holder 23 by hooking the snap-fit portion 8b to the snap-fit portion 23b. The CCD mask 8 is made of a thin plate-like metal or the like, and has a black coating on which an antireflection treatment is applied to the whole.

  For the CCD unit in which the CCD mask 8 is incorporated in the CCD holder 23, the optical filter 5 is incorporated from the back surface shown in FIG. Thereby, the front surface of the optical filter 5 is held by the back surface 8c of the CCD mask 8, and the position of the optical filter 5 in the optical axis direction is determined.

  Further, since the back surface 8c of the CCD mask 8 is attached to the attachment surface (optical axis orthogonal surface) 23a of the CCD holder 23, the position of the optical filter 5 in the optical axis direction is substantially the same position as the attachment surface 23a of the CCD holder 23. It becomes. This makes it possible to always maintain a stable position of the optical filter 5 in the optical axis direction regardless of the processing accuracy of the CCD mask 8.

  Further, the side surface of the optical filter 5 is held by the CCD holder 23, and the position in the plane orthogonal to the optical axis (in the optical axis orthogonal plane) is determined. More specifically, as shown in FIG. 10, the side surface of the optical filter 5 is held by the end surfaces 51 a, 51 b, 51 c of the holding member 51 provided integrally with the CCD holder 23, so that it is in the plane orthogonal to the optical axis. The position of is determined.

  Further, as shown in FIG. 9, the holding member 51 does not overlap with the outer shape of the CCD mask 8 in the plane orthogonal to the optical axis. Further, as shown in FIG. 7, the holding member 51 and the CCD mask 8 are disposed so as to overlap in the optical axis direction. Furthermore, the end faces 51a and 51b of the holding member 51 also serve as positioning in the plane orthogonal to the optical axis of the CCD mask 8, and are fitted to the end faces 8d and 8e of the CCD mask 8, respectively.

  Thus, by positioning the optical filter 5 and the CCD mask 8 in the optical axis orthogonal plane with the same member, it is possible to optimize the external size of the optical filter 5 with respect to the opening 8a of the CCD mask 8. This means that the outer size of the optical filter 5 can be minimized with respect to the opening 8a, and the manufacturing cost of the optical filter 5 can be reduced.

  Further, as compared with the conventional case, the thickness of the holding member 51 can be secured by adding the thickness of the CCD mask 8 to the thickness of the optical filter 5. Therefore, even when the optical filter 5 is thin, the holding member 51 can be molded without exceeding the resin molding limit.

  Further, as shown in FIG. 7, even when the external size of the CCD 4 is larger than the optical filter 5, the shape of the CCD rubber 6 is not broken. Therefore, as in the prior art, it is possible to form the CCD mask 8, the optical filter 5, the CCD rubber 6, and the CCD 4 made of a thin plate metal in order from the subject side in the optical axis direction. As described above, the lens barrel can be thinned even when the external size of the CCD is large or the optical filter is thin.

  Furthermore, in assembling the component parts, the CCD rubber 6 made of an elastic member is incorporated into the back surface of the optical filter 5, and the CCD holding unit 7 to which the CCD 4 is fixed by adhesion is further incorporated from the back surface. The CCD rubber 6 is sandwiched (sandwiched) between the back surface of the optical filter 5 and the front surface of the CCD holding unit 7. Then, the CCD holding unit 7 is fixed to the CCD holder 23 by the fixing screw 41, whereby the series of components are held.

  With such a configuration, impurities such as dust do not enter the optical filter 5 and the CCD 4. Further, by interposing a plurality of springs 42 as pressing members between the CCD holding unit 7 and the CCD holder 23, the CCD holding unit 7 receives a force in a direction away from the CCD holder 23. Accordingly, the position of the CCD 4 can be adjusted.

  The optical filter holding mechanism of the present embodiment includes a CCD mask 8 that regulates the position of the optical filter 5 in the optical axis direction, and a CCD holder 23 that regulates the position in the plane orthogonal to the optical axis. Further, a holding member 51 provided on the CCD holder 23 for holding the optical filter 5 is disposed overlapping the CCD mask 8 in the optical axis direction. That is, the holding member 51 that holds the optical filter 5 is arranged on the optical axis orthogonal plane that is orthogonal to the optical axis and that is substantially the same as the optical axis orthogonal plane on which the CCD mask 8 is arranged. As a result, even when the outer size of the CCD is larger than the outer size of the optical filter or when the optical filter is thin, it is possible to reduce the manufacturing error and reduce the thickness in the optical axis direction.

  Further, since the CCD mask 8 is incorporated into the CCD holder 23 from the object side opposite to the CCD 4 incorporation side, the CCD mask 8 can be easily incorporated. Further, since the optical filter 5 is pressed toward the CCD mask 8 by the CCD rubber 6 provided between the CCD holding unit 7 and the optical filter 5, the optical filter 5 is securely fixed and the optical axis of the optical filter 5 is fixed. The positional accuracy in the direction can be improved. Further, it is possible to prevent impurities such as dust from entering the CCD 4. Further, since the holding member 51 holds the optical filter 5 and restricts the position of the CCD mask 8 in the plane orthogonal to the optical axis, it is not necessary to provide another member for this positioning. Further, by positioning the optical filter 5 and the CCD mask 8 in the plane orthogonal to the optical axis with the same member, it is possible to optimize the outer size of the optical filter 5 with respect to the opening 8a of the CCD mask 8.

  The present invention is not limited to the configuration of the above-described embodiment, and any configuration can be used as long as the functions shown in the claims or the functions of the configuration of the present embodiment can be achieved. Is also applicable.

  For example, in the above-described embodiment, a CCD element is used as the image pickup element, but it is needless to say that a CMOS element may be used.

  In the above-described embodiment, a compact digital camera has been described as an example. However, the present invention can also be applied to a digital video camera and a digital SLR (single-lens reflex camera).

It is a perspective view which shows the external appearance of the digital camera 62 in the state which turned off the power supply in embodiment. It is a perspective view which shows the external appearance of the digital camera 62 of the state which turned on the power supply. It is sectional drawing which shows the structure of the zoom lens barrel 71 in the accommodation state. It is sectional drawing which shows the structure of the zoom lens barrel 71 in the imaging | photography possible state. It is a disassembled perspective view which shows the structure of the CCD unit seen from the back. It is a disassembled perspective view which shows the structure of the CCD unit seen from the front. 6 is a cross-sectional view showing a holding mechanism for the optical filter 5. FIG. It is a perspective view which shows the shape of CCD mask 8 seen from the back surface. It is a front view which shows the holding mechanism of the optical filter 5 in the state where the CCD mask 8 was attached. It is a figure which shows the holding mechanism of the optical filter 5 of the state which removed the CCD mask 8. FIG. It is sectional drawing which shows the holding mechanism of the optical element in the conventional imaging device. It is sectional drawing which shows the holding mechanism of the conventional optical element in case the external size of CCD is larger than an optical filter.

Explanation of symbols

4 CCD
5 Optical Filter 6 CCD Rubber 7 CCD Holding Member 8 CCD Mask 23 CCD Holder 51 Holding Member

Claims (4)

In the holding mechanism of the optical element that will be disposed on a plane perpendicular to the Oite optical axis in front of the image pickup device,
Disposed on a plane perpendicular to the optical axis, a regulating member for regulating the position of the optical axis of the optical element,
And an imaging unit holding member optical element holding member is found provided that holds the regulating member at the outer peripheral end surface of the regulating member with the outer peripheral side to hold the optical element of the optical element,
A part of the outer peripheral side surface of the optical element and a part of the outer peripheral end face of the restricting member are held on the same end face of the optical element holding member, thereby being in a plane perpendicular to the optical axis of the optical element and the restricting member. A holding mechanism for an optical element, wherein the position of the optical element is regulated . The optical element has a rectangular shape;
The regulating member has a snap fit portion fixed to the imaging unit holding member,
Positioning of the optical element by the optical element holding member is performed at two corners at diagonal positions in the optical element,
2. The optical device according to claim 1, wherein the positioning of the snap-fit portion of the regulating member is performed on two opposing sides provided on the outer diameter side of two corner portions where the optical element is not positioned. Element holding mechanism. The optical element holding member, in a plane perpendicular to the optical axis, the holding mechanism of the optical element according to claim 1 or 2, wherein the non-arranged overlapping with the outer shape of the regulating member.   An image pickup apparatus comprising the optical element holding mechanism according to claim 1.