JP2012073555A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus able to adjust the position of an optical element without receiving constraint of reducing the size of housings and internal structure.SOLUTION: The imaging apparatus has a bending optical element for changing the advancing direction of subject light, and a movable lens group located closer to an image surface than to the bending optical element and movable in the direction of an optical axis. The imaging apparatus comprises: the first housing supporting an image surface side optical system containing the movable lens group; the second housing supporting a subject side optical system containing the bending optical element and having power; a spacer selectively inserted between the first and second housings, thereby determining a space between them in the direction of the optical axis; and a fixing means for connecting the first and second housings with the spacer between them.

Description

  The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus provided with a position adjusting means for optical elements constituting an image pickup optical system.

  In the imaging apparatus, adjustments are required to absorb manufacturing errors and assembly errors in each optical element constituting the imaging optical system and its support mechanism. However, as the size of the imaging device is further reduced, it becomes difficult to incorporate an adjustment mechanism inside the housing of the imaging device or to secure a moving space for adjusting the optical element. In particular, as in Patent Document 1 and Patent Document 2, in an imaging apparatus of a type in which a thin optical system is used and an image sensor for imaging is fixedly supported in the casing, the space inside the casing In addition, this problem becomes significant because access to the internal structure becomes difficult in an assembled state.

JP 2008-242446 A JP 2010-181684 A

  An object of the present invention is to provide an imaging device capable of adjusting the position of an optical element without being restricted by a downsizing of a casing or a restriction of an internal structure.

  The present invention includes a movable lens group in an imaging apparatus having a bending optical element that changes the traveling direction of subject light, and a movable lens group that is located on the image plane side of the bending optical element and is movable in the optical axis direction. A first housing that supports the image-side optical system, a second housing that includes a bending optical element and supports a subject-side optical system having power, and selectively between the first housing and the second housing It is characterized by having a spacer inserted and determining a distance in the optical axis direction between the first housing and the second housing, and a fixing means for coupling the first and second housings with the spacer interposed therebetween.

  The second housing is provided with a holding portion for holding the subject side optical system and a pair of plate-like flanges extending to the side of the holding portion. It is preferable to provide a pair of flange support seats having a projecting shape having an entry space for the holding portion of the housing 2 and having end faces opposed to the pair of flanges of the second housing. The fixing means is preferably constituted by a fixing screw for fastening the flanges and the flange support seats together with spacers sandwiched between the facing surfaces of the pair of flanges and the pair of flange support seats.

  In addition to the bending optical element of the subject side optical system, the image side optical system may include a bending optical element that changes the traveling direction of the subject light that has passed through the movable lens group. Specifically, each of the bending optical element of the subject side optical system and the bending optical element of the image side optical system is a prism that reflects incident light at a substantially right angle, and the first and second housings are coupled by a fixing means. It is preferable that the optical arrangement is such that the incident optical axis to each prism and the outgoing optical axis from each prism are all in the same plane. In this case, the first housing has an opening on the side facing the outgoing optical axis from the prism constituting the image surface side optical system, and the prism of the image surface side optical system is formed on the cover substrate that closes the opening. It is preferable to adopt a configuration that supports an image sensor located on the optical axis of the light emitted from the projector.

  The first and second housings are preferably provided with positioning means for restricting the relative movement of the first and second housings in a direction perpendicular to the direction in which the spacers are sandwiched with the spacers sandwiched therebetween. . The positioning means is formed in the second housing, supporting the movable lens group in the first housing so that the movable lens group can move linearly in the optical axis direction, and having one end projecting from the first housing. And a guide shaft fitting hole into which the protruding end portion of the guide shaft can be fitted.

  According to the first aspect of the present invention, the image pickup optical system is divided into the subject side optical system including the bending optical element and the image plane side optical system including the movable lens group positioned on the image plane side from the first optical system. Since the second housing is provided and the distance between the first and second housings in the optical axis direction is adjusted by the spacer, the internal structure and the internal space are limited even if the size of each housing is reduced. Thus, an imaging apparatus capable of easily adjusting the position of the optical element is obtained.

It is a perspective view of an imaging device to which the present invention is applied. It is a perspective view in the state where a cover board and a press board were removed from the main housing of the imaging device. It is the front view which looked at the same imaging device from the photographic subject side. It is sectional drawing which follows the AA line of FIG. 3 of the imaging device. It is a perspective view of the disassembled state of the main housing and sub-housing of the imaging device. FIG. 6 is a perspective view of a disassembled state of a main housing and a sub-housing of the image pickup apparatus with a viewpoint position different from that of FIG. 5.

  As shown in FIG. 4, the imaging optical system of the imaging apparatus 10 includes a first lens group (subject side optical system) LG1, a first prism (bending optical element, subject side optical system) PR1, and a second lens group (image plane). Side optical system) LG2, a third lens group (image surface side optical system) LG3, and a second prism PR2 (bending optical element, image surface side optical system). The first prism PR1 and the second prism PR2 are substantially the same. It is a bending optical system that reflects a light beam at a right angle. More specifically, the first lens group LG1 is located in front of the incident surface of the first prism PR1 (subject side) and behind the exit surface of the first prism PR1 (image surface side). The first lens L1, the first prism PR1, the second lens L2, and the third lens L3 are in a fixed relationship that does not move relative to each other. The second lens group LG2 includes a fourth lens L4 and a fifth lens L5, and the third lens group LG3 includes a single lens sixth lens L6.

  The light beam from the subject incident on the first lens L1 along the first optical axis O1 is reflected at a substantially right angle in the direction along the second optical axis O2 by the reflecting surface of the first prism PR1, and is reflected on the second optical axis O2. The second lens L2 to the sixth lens L6 located at the first lens L6, the second prism PR2 is reflected by the reflecting surface of the second prism PR2 along the third optical axis O3 at a substantially right angle to the subject direction, and the light receiving surface of the imaging sensor 11 Imaged on top. The first optical axis O1 and the third optical axis O3 are substantially parallel, and are located in the same plane together with the second optical axis O2. In other words, the imaging optical system of the imaging apparatus 10 is an optical system having an optical axis bent in a U shape within a predetermined plane (hereinafter referred to as an optical axis plane). This imaging optical system is a zoom optical system with a variable focal length, and a zooming operation is performed by moving the second lens group LG2 and the third lens group LG3 in the direction along the second optical axis O2. Further, the third lens group LG3 is moved in the direction along the second optical axis O2 to perform focus adjustment. In the following description, the direction parallel to the first optical axis O1 and the third optical axis is taken as the X axis, and the direction parallel to the second optical axis O2 is taken as the Y axis. The optical axis plane is composed of X-axis and Y-axis components. The direction orthogonal to the optical axis plane is taken as the Z axis.

  Each optical element constituting the above imaging optical system is housed and held separately in a main housing (first housing) 12 and a sub-housing (second housing) 13. The lenses L1, L2 and L3 constituting the first lens group LG1 and the first prism PR1 are held in the sub housing 13 as an integral optical unit constituting the subject side optical system. On the other hand, in the main housing 12, the second lens group LG2, the third lens group LG3, and the second prism PR2 constituting the image plane side optical system are held, and among these, the second prism PR2 is fixed in the main housing 12. The second lens group LG2 and the third lens group LG3 are supported so as to be movable in the Y-axis direction.

  The main housing 12 is a box-like body that is long in the Y-axis direction and thin in the X-axis direction. As shown in FIG. 2, a front opening facing the subject side is opened and a front opening 14 is formed during photographing. Yes. In the main housing 12, two guide shafts (positioning means) 15 and 16 that are long in the Y-axis direction are provided apart from each other in the Z-axis direction with the optical axis plane interposed therebetween, and constitute the second lens group LG2. The second group holding frame 17 holding the fourth lens L4 and the fifth lens L5 and the third group holding frame 18 holding the third lens group LG3 (sixth lens L6) are respectively guided by the guide shaft 15 and the guide shaft 16. It is supported so that it can move straight in the Y-axis direction. Each of the second group holding frame 17 and the third group holding frame 18 is moved in the Y-axis direction under the rotational driving force of the drive shaft that is driven to rotate by the motors 19 and 20 provided in the main housing 12. In the main housing 12, a prism holding portion 21 that holds the second prism PR2 is formed near one end in the Y-axis direction. The front opening 14 of the main housing 12 is closed by a cover substrate 22. By engaging the positioning protrusions 23 (FIG. 2) provided on the main housing 12 side with the positioning holes 24 (FIG. 2) on the cover substrate 22 side, the mounting position of the cover substrate 22 with respect to the main housing 12 is determined. The cover substrate 22 is provided with the imaging sensor 11 at a position (position on the third optical axis O3) facing the emission surface of the second prism PR2 in the positioning state. The cover substrate 22 is held by a pressing plate 25.

  As shown in FIGS. 5 and 6, the sub-housing 13 includes a main body portion 26 that holds the first lens L1 and the first prism PR1, and a second lens L2 and a third lens L3 that protrude from the main body portion 26 in the Y-axis direction. A holding part of the subject-side optical system is constituted by the protrusion holding part 27 that holds the lens, and has a pair of flanges 28 protruding forward and backward from the main body part 26 in the Z-axis direction. The protrusion holding portion 27 has a non-circular outer surface shape including a pair of parallel planes extending in the Z-axis direction and a pair of arc surfaces connecting the pair of parallel planes. The pair of flanges 28 have a substantially symmetrical shape across the optical axis plane. In each flange 28, the surface facing the protruding direction of the protruding holding portion 27 is a planar spacer holding surface 29. An annular screw seat 30 is formed on the opposite surface. A screw insertion hole 31 is formed through the flange 28 in the Y-axis direction, and one end and the other end of the screw insertion hole 31 are open to the spacer clamping surface 29 and the screw abutment seat 30. The sub-housing 13 is further formed with an opposing flat surface 32 at a position surrounding the protruding holding portion 27, and a pair of guide shaft fitting holes (positioning means) 33 and 34 that open on the opposing flat surface 32 are protruding and held. It is formed so as to be spaced apart in the Z-axis direction across the portion 27. The pair of spacer clamping surfaces 29 and the opposing plane 32 are planes substantially orthogonal to the optical axis plane.

  A facing plane 35 that faces the facing plane 32 of the sub-housing 13 is formed in the Y-axis direction end of the main housing 12 opposite to the prism holding portion 21 that holds the second prism PR2. The opposing plane 35 is a plane substantially orthogonal to the optical axis plane, and a projection holding portion 27 of the sub-housing 13 can be fitted in the vicinity of the center (having a non-circular cross-sectional shape corresponding to the projection holding portion 27). A hole 36 is opened. The receiving hole 36 is formed penetrating in the Y-axis direction, and the exit surface of the third lens L3 constituting the first lens group LG1 is connected to the second lens group LG2 in a state where the protruding holding portion 27 is fitted in the receiving hole 36. It faces the entrance surface of the fourth lens L4 that constitutes it. On the opposing plane 35, the end portions of the guide shaft 15 and the guide shaft 16 are projected at both side positions in the Z-axis direction across the receiving hole 36 (see FIG. 6). The positional relationship between the guide shaft 15 and the protruding end portion of the guide shaft 16 is the same as the positional relationship between the guide shaft fitting hole 33 and the guide shaft fitting hole 34 in the sub-housing 13, and the protruding holding portion is formed in the receiving hole 36. 27, the protruding end of the guide shaft 15 is inserted into the guide shaft fitting hole 33, and the protruding end of the guide shaft 16 is inserted into the guide shaft fitting hole 34 (see FIG. 3). . The guide shaft fitting hole 34 is sized so that the protruding end of the guide shaft 16 is loosely fitted in the Z-axis direction, and between the guide shafts 15 and 16 and the guide shaft fitting holes 33 and 34. It is possible to absorb some accuracy errors. A pair of flange support seats 37 having a substantially symmetrical shape with respect to the optical axis plane are formed at both ends of the main housing 12 in the Y-axis direction with respect to the Z-axis direction with the opposed plane 35 interposed therebetween. . Each flange support seat 37 is a quadrangular columnar (box-shaped) projecting portion in the Y-axis direction, and a spacer clamping surface 38 that is a plane substantially orthogonal to the optical axis plane is formed on the end face. . In the flange support seat 37, a screw threading hole 39 opened on the spacer clamping surface 38 is formed with the axis line oriented in the Y-axis direction.

  The sub-housing 13 is inserted into the receiving hole 36 in the protruding holding portion 27, and the protruding end portions of the guide shaft 15 and the guide shaft 16 are inserted into the guide shaft fitting hole 33 and the guide shaft fitting hole 34, respectively. Positions in the X-axis and Z-axis directions with respect to the housing 12 are determined.

  Further, the position of the sub housing 13 in the Y-axis direction with respect to the main housing 12 is determined by the distance between the spacer clamping surface 29 of the flange 28 and the spacer clamping surface 38 of the flange support seat 37. A spacer 40 for adjusting the distance is sandwiched between the pair of flanges 28 (spacer clamping surface 29) and the pair of flange support seats 37 (spacer clamping surface 38). The spacer 40 has a rectangular plate shape, and a screw insertion groove 41 is formed from one side portion toward the center. A plurality of types of spacers 40 having different thicknesses are prepared, and a spacer 40 having an appropriate thickness is selected and inserted between each flange 28 and the flange support seat 37. Then, the shaft portion of the fixing screw 42 is screwed into the screw screwing hole 39 of the flange support seat 37 through the screw insertion hole 31 and the screw insertion groove 41 formed in each flange 28 and the spacer 40, and the head of the fixing screw 42. Tighten until the part comes into contact with the screw seat 30. Thereby, the sub-housing 13 is fixed to the main housing 12. By changing the thickness of the spacer 40 sandwiched between the spacer clamping surface 29 of each flange 28 and the spacer clamping surface 38 of each flange support seat 37 (by replacing the spacer 40 with a different thickness). The relative position in the Y-axis direction of the image plane side optical system supported in the main housing 12 and the subject side optical system supported in the sub housing 13 changes. More specifically, the distance between the third lens L3 and the fourth lens L4 changes. In the sub-housing 13, in addition to the first prism PR1, a first lens L1, a second lens L2, and a third lens group L3 (first lens group LG1) having a predetermined refractive power are held. Therefore, the effect of flange back adjustment in the entire imaging optical system can be obtained by changing the position of the sub-housing 13 in the Y-axis direction using the spacer 40.

  The imaging device 10 in a completed state in which the main housing 12 and the sub-housing 13 are joined with a spacer 40 interposed therebetween is shown in FIGS. Of the main body portion 26 of the sub-housing 13, the portion from the pair of flanges 28 to the protruding holding portion 27 is accommodated in the entry space formed between the pair of flange support seats 37 of the main housing 12, and is excellent in space efficiency. It becomes the composition. However, as can be seen from FIG. 3 and FIG. 4, a predetermined clearance is secured in the Y-axis direction between the opposed plane 32 of the main body portion 26 of the sub-housing 13 and the opposed plane 35 of the main housing 12. By replacing the spacer 40 with a thinner spacer, there remains room for adjustment in the direction in which the distance between the sub housing 13 and the main housing 12 in the optical axis direction is reduced. Conversely, the spacer 40 can be replaced with a spacer 40 that is thicker than that shown in the figure, and the distance between the sub housing 13 and the main housing 12 in the optical axis direction can be increased. The adjustment in the separation direction is preferably performed within a range in which the protruding end portions of the guide shafts 15 and 16 and the guide shaft fitting holes 33 and 34 are not detached.

  As described above, in the imaging apparatus 10 according to the present embodiment, unlike the conventional idea that the optical element position adjustment mechanism is provided in the housing (housing) that supports the optical system, the subject-side optical including the first prism PR1 is provided. The housing is divided into a main housing 12 that supports the system and a sub-housing 13 that supports the image-side optical system that is located on the image plane side of the main housing 12. The structure is adjusted by the spacer 40. Thereby, it is possible to adjust the position of the optical element easily and reliably without being restricted by conditions such as the size, the internal structure, and the internal space of each housing 12 and 13. In particular, this adjustment structure is effective in the imaging device 10 of the present embodiment in which the movable lens groups LG2 and LG3 and the imaging sensor 11 are supported in a thin housing with a bending optical system using the prisms PR1 and PR2. It is. That is, the supporting and driving mechanism of the movable lens groups LG2 and LG3, which are structurally complicated, and the peripheral structure of the imaging sensor 11 and the motors 19 and 20 with electrical wiring are integrated on the main housing 12 side to form a unit. When the system is adjusted, access to the inside of the unit on the main housing 12 side is unnecessary. Further, all the constituent elements (first prism PR1, first lens group LG1) of the subject side optical system housed and held on the side of the subunit 13 whose position is adjusted with respect to the main housing 12 are fixed elements for the subunit 13. Therefore, after these are assembled in the sub-housing 13 and unitized, there is no possibility of an error in accuracy, and handling at the time of position adjustment using the spacer 40 is easy. The means for adjusting the distance between the main housing 12 and the sub-housing 13 is a simple plate-like spacer 40, and the main housing 12 and the sub-housing 13 are coupled and fixed by a fixing screw 42 with the spacer 40 sandwiched therebetween. Since the adjustment is completed only by the adjustment, the adjustment structure itself is simple with a small number of parts and excellent workability.

  In addition, one end of the guide shaft 15 and the guide shaft 16 that linearly guides the lens groups LG2 and LG3 movable in the Y-axis direction in the main housing 12 is projected from the main housing 12, and the guide shaft 15 and the guide shaft 16 By inserting the protruding end into the guide shaft fitting hole 33 and the guide shaft fitting hole 34 of the sub-housing 13, the direction (X axis direction and Z axis direction) perpendicular to the clamping direction (Y axis direction) of the spacer 40 The main housing 12 and the sub-housing 13 are positioned relative to each other. For this reason, when adjusting the distance in the Y-axis direction using the spacer 40, positional displacement between the main housing 12 and the sub-housing 13 is prevented, and excellent workability can be obtained also in this respect.

  The present invention is not limited to the illustrated embodiment. For example, in the illustrated embodiment, the subject-side optical system held by the sub-housing 13 includes the first lens group LG1 and the first prism PR1, but the incident surface and the exit surface of the first prism PR1 are refracted to a predetermined degree. It can be formed as a concave surface or a convex surface having a force, and the prism itself can have power. In this case, the subject-side optical system can be configured by a single prism. That is, the subject-side optical system held by the sub-housing 13 has a power to change the focal position in accordance with the change in the optical axis position and satisfies the condition that it includes a bent optical element such as a prism. Good.

  In the illustrated embodiment, the bending optical element in the optical system is a prism that reflects subject light at a substantially right angle. However, the bending optical element in the present invention is not limited to such a right-angle reflecting prism, and the object light travels. Any device having a function of changing the direction can be used. For example, a mirror can be selected as the bending optical element.

  In the illustrated embodiment, the second prism PR2 is supported as the second bending optical element in the main housing 12, but the second prism PR2 is not provided, and an image sensor is provided on the extension of the second optical axis O2. The present invention can also be applied to the optical arrangement of the arranged L-shaped optical path. Even in this optical arrangement, since the electrical system including the lens group LG2 and LG3 supporting drive mechanism and the imaging sensor is mounted, the construction described in the above description is performed in that the structure in the main housing 12 is complicated and the space is small. Common with form. Therefore, it is effective to employ an adjustment mechanism that sandwiches the spacer 40 between the main housing 12 and the sub-housing 13 instead of inside the main housing 12.

  Further, in the illustrated embodiment, the protruding end portions of the guide shaft 15 and the guide shaft 16 are inserted into the guide shaft fitting hole 33 and the guide shaft fitting hole 34 of the sub housing 13, thereby positioning the main housing 12 and the sub housing 13. However, only the guide shaft 15 may be projected from the main housing 12 and inserted into the guide shaft fitting hole 33 for positioning. In this case, the rotation of the sub-housing 13 with respect to the main housing 12 can be restricted by the flat portion and the circular arc surface of the protrusion holding portion 27 coming into contact with the flat portion and the circular arc surface of the receiving hole 36, respectively. Alternatively, only the guide shaft 16 protrudes from the main housing 12 and is inserted into the guide shaft fitting hole 34 to perform positioning in the X-axis direction, and by engaging the arc surface of the protrusion holding portion 27 and the arc surface of the receiving hole 36. It is also possible to adopt a mode in which positioning in the Z-axis direction is performed.

DESCRIPTION OF SYMBOLS 10 Imaging device 11 Imaging sensor 12 Main housing (1st housing)
13 Sub-housing (second housing)
15 16 Guide shaft (positioning means)
17 2nd group holding frame 18 3rd group holding frame 22 Cover substrate 25 Holding plate 26 Main body part (holding part)
27 Projection holding part (holding part)
28 Flange 29 Spacer clamping surface 30 Screw seat 31 Screw insertion hole 33 34 Guide shaft fitting hole (positioning means)
36 receiving hole 37 flange support seat 38 spacer clamping surface 39 screw screwing hole 40 spacer 41 screw insertion groove 42 fixing screw LG1 first lens group (subject side optical system)
LG2 Second lens group (image surface side optical system)
LG3 Third lens group (image side optical system)
PR1 first prism (bending optical element, subject side optical system)
PR2 Second prism (bending optical element, image plane side optical system)
O1 First optical axis O2 Second optical axis O3 Third optical axis

Claims (7)

In an imaging apparatus having a bending optical element that changes a traveling direction of subject light, and a movable lens group that is located on the image plane side of the bending optical element and is movable in the optical axis direction,
A first housing for supporting an image plane side optical system including the movable lens group;
A second housing that includes the bending optical element and supports a subject-side optical system having power;
A spacer that is selectively inserted between the first housing and the second housing and determines a distance in the optical axis direction between the first housing and the second housing; and the first and second sandwiching the spacer Fixing means for joining the housings;
An imaging device comprising: The imaging device according to claim 1,
A holding portion for holding the subject side optical system provided in the second housing, and a pair of plate-like flanges extending to the side of the holding portion;
A pair of flange support seats provided on the first housing, each having a protruding shape having an entry space for the holding portion therebetween, the end surfaces of which are opposed to the pair of flanges;
With
The fixing means includes a fixing screw for fastening the flanges and the flange support seats together with the spacers sandwiched between the opposing surfaces of the pair of flanges and the pair of flange support seats. Imaging device. 3. The imaging apparatus according to claim 1, wherein the image plane side optical system includes a bending optical element that changes a traveling direction of subject light passing through the movable lens group separately from the bending optical element of the subject side optical system. An imaging apparatus comprising: 4. The imaging apparatus according to claim 3, wherein each of the bending optical element of the subject side optical system and the bending optical element of the image side optical system includes a prism that reflects incident light at a substantially right angle. An image pickup apparatus characterized in that when the first housing and the second housing are combined, an incident optical axis to each prism and an outgoing optical axis from each prism are located in the same plane. 5. The imaging device according to claim 4, wherein the first housing has an opening on a side facing an emission optical axis from a prism constituting the image plane side optical system, and the cover substrate covers the opening. An image pickup apparatus supporting an image pickup sensor positioned on an optical axis emitted from the prism of the image plane side optical system. 6. The imaging device according to claim 1, wherein the first and second housings have a first state in a direction perpendicular to a spacer clamping direction when the spacer is clamped. An image pickup apparatus comprising: positioning means for restricting relative movement between the first housing and the second housing. The imaging apparatus according to claim 6, wherein the positioning means is
A guide shaft provided in the first housing so as to support the movable lens group so as to be linearly movable in the optical axis direction and having one end projecting from the first housing;
A guide shaft fitting hole formed in the second housing, into which the protruding end of the guide shaft can be fitted;
An imaging device comprising:

Images