JP2015075652A - Optical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress floating of flexible substrates without increasing the thickness of correction lens units.SOLUTION: An optical device comprises: a correction lens that corrects an image blurring in an optical system; a correction lens retaining frame that retains the correction lens; a securing part by which the correction retaining frame is retained movably in a direction intersecting an optical axis of the optical system; a permanent magnet that is secured in either one of the correction lens frame and the securing part; a drive coil that is secured in the other of the correction lens frame and the securing part, and generates drive force relative to a magnet field of the permanent magnet when electrified; a flexible substrate that supplies power to the drive coil; and a plate-like member that sandwiches at least flexible substrate between the drive coil and the plate-like member, and is formed by a magnetic substance to be attracted to the permanent magnet.

Description

  The present invention relates to an optical apparatus.

There is an optical apparatus provided with a camera shake correction device. The camera shake correction apparatus includes an actuator that drives a correction lens (see, for example, Patent Document 1).
Patent document 1 JP2013-088684A

  The actuator in the camera shake correction apparatus includes a coil, a magnet, a yoke, a flexible substrate, and the like that are overlapped in the optical axis direction of the optical system. For this reason, the camera shake correction apparatus becomes thick in the optical axis direction, and it becomes difficult to narrow the interval between the other adjacent optical member and the correction lens.

  According to the first aspect of the present invention, the correction lens that corrects image blur in the optical system, the correction lens holding frame that holds the correction lens, and the correction lens holding frame can be moved in a direction that intersects the optical axis of the optical system. A fixed part that supports the lens, a permanent magnet fixed to one of the correction lens holding frame and the fixed part, and a fixed magnet that is fixed to the other of the correction lens holding frame and the fixed part and is driven against the magnetic field of the permanent magnet when energized. An optical device comprising: a drive coil that generates force; a flexible board that supplies power to the drive coil; and a plate-like member that is sandwiched between at least the flexible board and is formed of a magnetic material and attracted to a permanent magnet Equipment is provided.

  The summary of the invention does not enumerate all the features of the present invention. Sub-combinations of these feature groups can also be an invention.

1 is a schematic diagram of an imaging apparatus 100. FIG. 3 is a cross-sectional view of a correction lens unit 220. FIG. 4 is a perspective view of a correction lens unit 220. FIG. 4 is a perspective view of a correction lens unit 220. FIG. 3 is a schematic diagram of an actuator 240. FIG.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Not all combinations of features described in the embodiments are essential for the solution of the invention.

  FIG. 1 is a schematic diagram of the imaging apparatus 100. The imaging device 100 is an example of an optical device having a function of correcting image blur. The imaging device 100 includes a lens barrel 110 and a camera body 120. The lens barrel 110 has an optical system 112 including a plurality of lenses arranged on the optical axis X. The camera body 120 has an image sensor 122.

  The imaging device 100 captures an object image formed by the optical system 112 of the lens barrel 110 on the light receiving surface of the image sensor 122 by recording it as an electrical signal. In the following description, the object side with respect to the lens barrel 110 is described as the front side of the imaging apparatus 100. Further, the camera body 120 side with respect to the lens barrel 110 is referred to as a rear side.

  The lens barrel 110 further includes an image blur correction unit 200 that corrects image blur in the optical system 112. The image blur correction unit 200 includes a detection unit 210 and a correction lens unit 220.

  The detection unit 210 includes acceleration sensors 212 and 214 that detect acceleration in two directions that intersect the optical axis X and intersect each other. The detection unit 210 calculates the displacement of the lens barrel 110 based on the acceleration detected by the acceleration sensors 212 and 214.

  The correction lens unit 220 includes a correction lens 230 and an actuator 240. The correction lens 230 forms a part of the optical system 112 and is displaced in a direction intersecting the optical axis X, thereby displacing the image forming position of the image formed by the optical system 112 in the direction intersecting the optical axis X.

  The actuator 240 drives the correction lens 230 to move along the moving plane intersecting the optical axis X in order to cancel the image blur caused by the displacement of the lens barrel 110 calculated by the detection unit 210. As a result, image blur in the optical system 112 is compensated, and a clear image is formed on the image sensor 122.

  FIG. 2 is a cross-sectional view of the correction lens unit 220. The correction lens unit 220 includes a correction lens holding frame 232, a fixed frame 250, and a cover frame 260.

  In the correction lens unit 220, the lens holding frame 232 holds the correction lens 230. The lens holding frame 232 holds a magnet 242 that forms part of the actuator 240. The magnet 242 is formed of a permanent magnet such as ferrite. Thereby, the lens holding frame 232, the correction lens 230, and the magnet 242 become an integrated assembly.

  In the correction lens unit 220, the fixed frame 250 supports the lens holding frame 232 so as to be movable in a moving plane intersecting the optical axis X. The fixed frame 250 has an opening 252 that opens around the optical axis X. Therefore, the left surface of the correction lens 230 held in the lens holding frame 232 in the drawing is exposed to the outside of the correction lens unit 220 without being blocked by the fixed frame 250.

  The fixed frame 250 holds a coil 244 that forms a part of the actuator 240 at a position facing the magnet 242 of the held lens holding frame 232. A flexible substrate 270 that supplies driving power is coupled to the coil 244. The flexible substrate 270 goes around the edge of the fixed frame 250 and is drawn out to the outer surface of the fixed frame 250. As a result, driving power can be supplied from the outside to the coil 244 to generate a driving force for the magnet 242.

  In the lens barrel 110, other members such as another lens, an aperture unit, and a shutter are disposed adjacent to the correction lens unit 220. In FIG. 2, as an example, the shape of the aperture unit having protrusions in the optical axis X direction is indicated by a broken line.

  A backing plate 280 is provided on the side opposite to the fixed frame 250 with respect to the flexible substrate 270. The backing plate 280 is made of a magnetic material, and is attracted to the magnet 242 and also functions as a yoke. The backing plate 280 has a thin plate shape and is disposed in parallel with the moving surface of the lens holding frame 232 that intersects the optical axis X.

  In the fixed frame 250 of the correction lens unit 220, the backing plate 280 has a shape that overlaps both the two coils 244 and 245. Thereby, the driving efficiency of the two sets of actuators 240 and 241 can be improved without increasing the number of steps for assembling the correction lens unit 220. In addition, since the magnetic flux leakage from the actuators 240 and 241 is suppressed, the actuators 240 and 241 are prevented from being influenced by other magnetic circuits arranged around the lens barrel 110, and the magnetic fields of the actuators 240 and 241 are reduced. The influence on the surroundings is also suppressed.

  In the correction lens unit 220, the cover frame 260 is disposed around the correction lens 230 held by the lens holding frame 232 without blocking the correction lens 230. The cover frame 260 is fixed to the fixed frame 250 with a part of the lens holding frame 232 interposed therebetween. Therefore, the cover frame 260 is not displaced with respect to the lens barrel 110.

  The cover frame 260 holds a magnetic sensor 290 such as a Hall element in the vicinity of the magnet 242 held by the lens holding frame 232. The magnetic sensor 290 detects a change in the magnetic field formed by the actuator 240 when the magnet 242 is displaced together with the lens holding frame 232. Therefore, the displacement of the lens holding frame 232 can be detected based on the output of the magnetic sensor 290. Furthermore, by referring to the detected displacement of the lens holding frame 232, the operation of the actuator 240 can be accurately feedback-controlled.

  In the cover frame 260, the yoke plate 310 is disposed outside the magnetic sensor 290. The yoke plate 310 converges the magnetic flux at one end of the magnetic field formed by the magnet 242 and the coil 244.

  Further, a presser spring 320 is disposed outside the yoke plate 310 in the cover frame 260. The presser spring 320 presses the magnetic sensor 290 and the yoke plate 310 toward the cover frame 260 to prevent the cover sensor 260 from falling off.

  FIG. 3 is a perspective view showing the correction lens unit 220 as viewed from the cover frame 260 side. As illustrated, in the correction lens unit 220, a bracket 254 is provided on the fixed frame 250. The fixed frame 250 can be screwed to the lens barrel 110 using the bracket 254.

  In the correction lens unit 220, the cover frame 260 is fixed to the fixed frame 250 by fixing screws 266 and 268. As a result, the fixed frame 250 and the cover frame 260 are in a state of sandwiching the lens holding frame 232 on the upper side and the left side of the correction lens 230 in the drawing. The cover frame 260 has a notch 262 that avoids the lens holding frame 232 and does not prevent the lens holding frame 232 from being displaced.

  In the correction lens unit 220, the lens holding frame 232 has a plurality of locking portions 238. The locking portion 238 protrudes outward in the radial direction of the correction lens 230. Also, in the fixed frame 250, locking portions 258 are provided at positions corresponding to the locking portions 238 of the lens holding frame 232.

  These locking portions 238 and 258 are connected by a tension spring 330 biased in a direction in which the length contracts. As a result, the lens holding frame 232 is pulled toward the fixed frame 250. It should be noted that at least three sets of the locking portions 238 and 258 and the tension springs 330 are provided including those not appearing in the drawing.

  Further, a plurality of rolling balls are sandwiched between the lens holding frame 232 and the fixed frame 250. Thereby, the lens holding frame 232 can move smoothly in parallel with the fixed frame 250.

  In the correction lens unit 220, the lens holding frame 232 holds the other magnet 243 in a position corresponding to the side of the correction lens 230 in the drawing in addition to the magnet 242 indicated by a broken line in the drawing. Corresponding to the magnet 243, the fixed frame 250 is provided with a coil 245, and the cover frame 260 is provided with a magnetic sensor 291. Therefore, two sets of actuators 240 and 241 are formed in the correction lens unit 220.

  As a result, the pair of coils 244 and 245 generate driving forces orthogonal to each other and displace the lens holding frame 232 two-dimensionally on a moving plane orthogonal to the optical axis X. The pair of magnetic sensors 290 and 291 detect the displacement of the lens holding frame 232 in the direction orthogonal to each other with high sensitivity, and detect the two-dimensional position of the lens holding frame 232 on the moving plane with high accuracy.

  In the cover frame 260 of the correction lens unit 220, the yoke plate 310 has a shape that overlaps both the two magnets 242 and 243. Thereby, the driving efficiency of the two sets of actuators 240 and 241 and the detection sensitivity of the magnetic sensors 290 and 291 can be improved without increasing the number of steps for assembling the correction lens unit 220. In addition, since the magnetic flux leakage from the actuators 240 and 241 is suppressed, the actuators 240 and 241 are prevented from being influenced by other magnetic circuits arranged around the lens barrel 110, and the magnetic fields of the actuators 240 and 241 are reduced. The influence on the surroundings is also suppressed.

  A connector 272 is provided on the side surface of the fixed frame 250. A flexible substrate 274 arranged in the longitudinal direction of the lens barrel 110 is coupled to the connector 272. By the flexible substrate 274, the correction lens unit 220 receives power, a control signal, and the like from the outside. A signal output from the correction lens unit 220 is also sent out through the flexible substrate 274.

  FIG. 4 is a perspective view showing the correction lens unit 220 as viewed from the fixed frame 250 side. In the correction lens unit 220, a flexible substrate 270 and a backing plate 280 are disposed on the surface of the fixed frame 250.

  Further, it can be seen that a locking portion 258, a tension spring 330, and a bracket 254 that are not shown in FIG. Thereby, the fixed frame 250 is stably fixed to the lens barrel 110. The tension spring 330 holds the lens holding frame 232 with respect to the fixed frame 250 stably.

  The flexible substrate 270 is connected to the coils 244 and 245, wraps around the edge of the fixed frame 250, circulates around the opening 252 on the surface of the fixed frame 250, and then, on the side of the fixed frame 250 in the drawing, Coupled to connector 272. Accordingly, the flexible substrate 270 is coupled to the flexible substrate 274 via the connector 272, and driving power for the coils 244 and 245 is supplied from the outside.

  In the correction lens unit 220, a backing plate 280 is disposed on the flexible substrate 270 so as to overlap the opening 252. When viewed from a direction parallel to the optical axis X, the backing plate 280 is disposed at a position that overlaps both of the plurality of coils 244 and 245 fixed to the fixed frame 250. Similarly, the coils 244 and 245 are arranged at positions overlapping the magnets 242 and 243 in the optical axis X direction.

  Here, the backing plate 280 is formed of a magnetic material having a high magnetic permeability such as SPCC (cold rolled steel). Thereby, at least a part of the backing plate 280 is attracted toward the fixed frame 250 by the magnetic force of the magnets 242 and 243. Therefore, the backing plate 280 can prevent the floating substrate 270 from being pushed by pressing the flexible substrate 270 against the fixed frame 250.

  Thus, in the correction lens unit 220, the backing plate 280 suppresses the floating of the flexible substrate 270. Further, since the backing plate 280 presses the flexible substrate 270 by the magnetic force of the magnets 242, 243, it is not necessary to increase the thickness of the backing plate 280 in order to increase the rigidity of the backing plate 280 as compared with the case where the backing plate 280 is fixed by screwing. Good. Therefore, the correction lens unit 220 thins the backing plate 280 itself and prevents the flexible substrate 270 from floating, thereby reducing the thickness of the member disposed on the outer surface of the fixed frame 250. Other members can be arranged in the immediate vicinity of the outer surface of the, without interfering with each other.

  Note that the backing plate 280 only needs to overlap a part of the coil 244. Further, the backing plate 280 may not have the same shape as the flexible substrate 270. That is, as long as at least a portion overlaps the flexible substrate 270, the floating of the flexible substrate 270 from the fixed frame 250 can be suppressed.

  Further, as described above, the backing plate 280 is attracted to the fixed frame 250 by the magnetic force of the magnet 242. However, in the process of assembling the correction lens unit 220, the backing plate 280 may be temporarily fixed with a double-sided tape or the like. However, when temporarily fixing, the entire backing plate 280 may be attached to the extent that it can be prevented from falling off the fixed frame 250 and the flexible substrate 270 without attaching the entire backing plate 280.

  Further, in the completed correction lens unit 220, the backing plate 280 may be fixed by combining adsorption by the magnet 242 and adhesion by a double-sided tape, an adhesive, or the like. In this case, the backing plate 280 is bonded to at least one of the flexible substrate 270 and the fixed frame 250. Still further, the backing plate 280 may be mechanically fixed to the fixed frame 250 by caulking such as claws and pins formed on at least one of the backing plate 280 and the fixing frame 250, heat caulking, or the like.

  The fixed frame 250 has a step 256 formed along the outer edges of the flexible substrate 270 and the backing plate 280. The backing plate 280 abuts against the step 256 on the side circumferential end surface, and is mechanically positioned by the step 256 in the direction orthogonal to the optical axis X, that is, the surface direction of the fixed frame 250. Thereby, when an impact or the like is applied from the side of the lens barrel 110, the position of the backing plate 280 can be prevented from shifting.

  The positioning structure may be a step provided on the fixed frame 250, a positioning protrusion, a slit, or the like. Further, a part of the backing plate 280 may be deformed by press work or the like and fitted to the fixed frame 250.

  FIG. 5 is a schematic cross-sectional view of the correction lens unit 220 and shows the structure of the magnetic circuit in the actuator 240. In the actuator 240 of the correction lens unit 220, the magnet 242 always generates a magnetic field. In FIG. 5, the magnetic field of the present embodiment is indicated by a one-dot chain line. Further, for the purpose of comparison with the present embodiment, a virtual magnetic field generated when the backing plate 280 is not a magnetic body is also shown by a broken line.

  The magnetic field generated by the magnet 242 is converged by the backing plate 280 disposed on the back surface of the coil 244 and the yoke plate 310 disposed on the back side with respect to the magnet 242 and is a virtual magnetic field indicated by a broken line in the drawing. Rather, it passes through the coil 244 in a straight line with a high density.

  As a result, the driving force generated by the actuator 240 with respect to the input driving power is increased, the driving efficiency of the actuator 240 is improved, and the response when correcting the image blur is increased. Thus, in the correction lens unit 220, the backing plate 280 functions as a yoke even on the fixed frame 250 side that does not include a dedicated yoke.

  Further, in the correction lens unit 220 in which the backing plate 280 also functions as a yoke, leakage of magnetic flux from the actuator 240 to the outside is suppressed. Therefore, another member using magnetism such as a motor can be disposed in the vicinity of the correction lens unit 220. Further, since the backing plate 280 shields the magnetic flux from the outside, the correction lens unit 220 is hardly affected even when other members that generate a magnetic field are arranged.

  The operation of the backing plate 280 as described above also occurs in the other actuators 241 provided in the correction lens unit 220 in the same manner. Note that the backing plate 280 does not have to have a completely overlapping shape as long as a part of the backing plate 280 overlaps with the coils 244 and 245 in the direction of the optical axis X. In the above example, the lens barrel 110 used in the interchangeable lens imaging apparatus has been described as an example. However, the above structure is applied to other optical devices such as a telescope, a surveying instrument, a microscope, and a rangefinder. Is also applicable.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Imaging device, 110 Lens barrel, 112 Optical system, 120 Camera body, 122 Image sensor, 200 Image blur correction part, 210 Detection part, 212, 214 Acceleration sensor, 220 Correction lens unit, 230 Correction lens, 232 Lens holding frame 238, 258 Locking part, 240, 241 Actuator, 242, 243 Magnet, 244, 245 Coil, 250 Fixed frame, 252 Opening part, 254 Bracket, 256 Step, 260 Cover frame, 262 Notch part, 266, 268 Fixed Screw, 270, 274 Flexible substrate, 272 connector, 280 Backing plate, 290, 291 Magnetic sensor, 310 Yoke plate, 320 Presser spring, 330 Tension spring

Claims (5)

A correction lens for correcting image blur in the optical system;
A correction lens holding frame for holding the correction lens;
A fixing portion that supports the correction lens holding frame so as to be movable in a direction intersecting the optical axis of the optical system;
A permanent magnet fixed to one of the correction lens holding frame and the fixed portion;
A driving coil that is fixed to the other of the correction lens holding frame and the fixing portion and generates a driving force with respect to the magnetic field of the permanent magnet when energized;
A flexible substrate for supplying power to the drive coil;
A plate-like member that is sandwiched between at least the flexible substrate and formed of a magnetic material and is attracted to the permanent magnet;
An optical instrument comprising:   The optical apparatus according to claim 1, wherein the plate-like member is disposed in a range overlapping with the plurality of drive coils.   The optical device according to claim 1, wherein the plate-like member has the same shape as the flexible substrate in a region overlapping with the correction lens holding frame.   The optical device according to any one of claims 1 to 3, wherein the driving coil, the flexible substrate, and the plate-like member are fixed to the fixing portion.   The at least one of the said fixing | fixed part and the said plate-shaped member has a positioning part which mechanically positions the said plate-shaped member with respect to the said correction lens holding frame about the direction which cross | intersects the said optical axis. Optical equipment.

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