JP2004054180A - Table device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small table device having a position detecting function with high precision. <P>SOLUTION: The table device B is equipped with moving tables 12, 13 and 17 which is arranged opposite to a base member 11 and can move to the base member 11 in two non-parallel axial directions and couples of position sensors 82X and 82Y, and 62X and 62Y which comprise light emission parts 82X and 82Y and light reception parts 62X and 62Y and detect the positions of the moving tables in the two axial directions. Each position sensor is so provided that one of its light emission part and light reception part is arranged on the moving table 17 and optical paths X and Y between the light emission part and light reception part are parallel to the movement plane of the moving table and not parallel to other optical paths. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a biaxially movable table device that is preferably used for camera shake correction of a digital camera, pixel shift of an image sensor, and the like.
[0002]
[Prior art]
In a table apparatus provided with a moving table arranged opposite to a base member and arbitrarily movable in two axial directions with respect to the base member, there are various methods for optically detecting the position of the moving table with respect to the base member. Is disclosed. Among them, a device using a set of an LED and a PSD is widely used from the viewpoint of high measurement accuracy and downsizing of the measurement device. A position detection mechanism using a set of an LED and a PSD is disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-42377. In the position detection using the set of the LED and the PSD, the LED is fixed to the moving table so as to emit light in parallel with the optical axis of the subject, and the position of the spot light moving with the movement of the moving table is represented by a linear shape. Detection is performed using a PSD having a light receiving surface.
[0003]
In general, the PSD calculates a position from a current value ratio inversely proportional to the distance between the center of gravity of the spot light hitting the light receiving surface and the distance between both terminals. Therefore, the accuracy can be improved by increasing the diameter of the spot light in view of dark noise and the like. Conversely, when the distance between the LED and the PSD is short, the spot diameter becomes small, so that a difficult-to-control error such as a deviation between the LED light emitting position and the slit is enlarged, and the measurement range is greatly reduced. On the other hand, with respect to the problem that the detection range is reduced by increasing the spot diameter, various measures such as using a large PSD to widen the detection range have been devised. However, using a large PSD not only increases the cost, but also increases the size of the mechanism. Further, in order to enhance the directionality of light emission of the LED, it is necessary to use a lens or the like having a higher directionality of light emission by attaching a lens or the like, and there is a problem that a large-sized LED needs to be used.
[0004]
That is, in order to increase the accuracy of position detection, it is preferable to increase the distance between the LED and the PSD and to increase the size of the mechanism itself using a large LED or PSD. However, it is often difficult to incorporate a large-sized position detection mechanism in order to incorporate it into an imaging device due to the design matching with the optical system. In recent years, small cameras have become mainstream, and the difficulty of using a table apparatus having a large position detection mechanism has become remarkable. In particular, in the case of a table device used for driving an imaging element, if the distance between the imaging optical system and the imaging surface is too large, the entire camera becomes large. Therefore, it is necessary to provide a moving table within a certain distance from the lens barrel. There is. In this case, it is difficult to use a large position detecting mechanism, and as a result, the distance between the LED and the PSD must be shortened and the position detecting mechanism using a small element must be used at the expense of accuracy. It was in the situation.
[0005]
[Problems to be solved by the invention]
Therefore, a technical problem to be solved by the present invention is to provide a table apparatus having a small size and a highly accurate position detecting function.
[0006]
[Means for Solving the Problems and Functions / Effects]
The present invention provides a table device having the following configuration to solve the above technical problem.
[0007]
The table device is provided with a moving table arbitrarily movable with respect to the base member in two axial directions that are arranged opposite to the base member and that are not parallel to each other, and a moving table that includes a light emitting unit and a light receiving unit. And a pair of position sensors for detecting positions. In each of the position sensors, one of the light emitting unit and the light receiving unit is disposed on a moving table, and an optical path between the light emitting unit and the light receiving unit is parallel to a moving plane of the moving table. Moreover, the optical paths are provided so as not to be parallel to each other.
[0008]
In the above configuration, the moving table can arbitrarily move in two axes directions that are not parallel to each other, for example, orthogonal to each other. The position of the moving table with respect to the base member is determined by a position sensor including a light emitting unit including, for example, an LED, and a light receiving unit including, for example, a position detecting element (PSD), a CCD, and a MOS sensor. The position sensors are provided in a pair to detect the positions of the moving table in the two axial directions.
[0009]
In each position sensor, one of the light-emitting unit and the light-receiving unit is provided on the moving table, and the optical path between the light-emitting unit and the light-receiving unit is parallel to the moving plane of the moving table. Is provided. Therefore, the distance between the light emitting unit and the light receiving unit can be increased regardless of the distance between the moving table and the base member. Therefore, the uncontrollable position error sensitivity is reduced, and it is not necessary to increase the size of the light receiving unit such as a PSD. In addition, since the light beam from the light emitting unit can be configured to pass on the moving table, it is not necessary to separately secure a space necessary for the optical path of the position sensor, and the table device itself can be downsized. .
[0010]
The table device of the present invention can be specifically configured in various modes as described below.
[0011]
Preferably, the position sensors are arranged such that their optical paths intersect.
[0012]
In the above configuration, by arranging the optical paths in two or more detection directions so as to overlap with each other, the space occupied by the optical paths can be reduced, and the overall size of the apparatus can be reduced.
[0013]
It is preferable that the light emitting units of the respective position sensors are arranged in one light emitting side holder, and the light receiving units of the respective position sensors are arranged in one light receiving side holder. That is, by holding the same kind of members constituting each position sensor in the same holder, it is possible to easily adjust the mounting accuracy at the time of assembling, and it is possible to maintain the positional relationship in the detection direction with high accuracy. .
[0014]
The table device of each of the above configurations can be suitably used as a movement / position detection unit of the image sensor. Specifically, by moving the image sensor, it is possible to reduce the size of the image pickup apparatus capable of performing camera shake correction and pixel shift with high accuracy.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of an imaging device using the table device of the present invention will be described with reference to the drawings.
[0016]
As shown in FIG. 1, the imaging device is used by being mounted on a digital camera 1 including a camera body 2 and an imaging device 10. The imaging device 10 includes an optical unit A including a plurality of lenses 4 and a lens barrel 3, and an imaging unit B having an image stabilization function including an image sensor used in connection with the optical unit. As shown by an arrow 5 in FIG. 1, when the digital camera 1 is shaken during photographing and the optical axis of the optical unit A is shifted from the position indicated by L in FIG. To correct the deviation of the optical axis. The table device of the present invention is used in the imaging unit B to move the imaging device for the above-mentioned camera shake correction function.
[0017]
FIG. 2 is an exploded perspective view of the imaging device 10. FIG. 3 is a cross-sectional view of the imaging device of FIG. 2 taken along a line II. FIG. 4 is a cross-sectional view of the imaging device of FIG. 2 taken along a line II-II. FIG. 5 shows a cross-sectional view of the imaging device of FIG. 2 cut along a III-III cross section.
[0018]
First, the imaging unit will be described. The imaging unit B includes a base member 11 serving as a base, a first stage 13 that moves in a horizontal direction (hereinafter, this direction is referred to as an X-axis direction) with respect to the base member 12, and a first stage 13. A second stage 12 that moves in a direction perpendicular to the moving direction (X-axis direction) (hereinafter, described as a Y-axis direction), an image sensor 15 fixed to the second stage, and a second member 12 fixed to a base member. A PSD holder mounted with a position detection element (hereinafter, referred to as PSD) for detecting the amount of movement of the first and second stages. Further, a dustproof cap 19 for sealing the entire image pickup unit from the outside together with the bottom surface 3a of the optical unit is provided.
[0019]
The base member 11, the first stage 13, the second stage 12, and the PSD holder 14, which support the image sensor 15 in a swingable manner, include the image sensor 15 (including a first substrate that processes information from the image sensor). It is located so as to fill the extra space of the outer periphery of the bottom surface of the lens barrel 3 and the outer periphery of the image pickup device 15.
[0020]
The base member 11 is a plate provided substantially perpendicular to the direction of the optical axis L (hereinafter referred to as the Z-axis direction), and is a metal frame 23 having a large hole 24 for the optical axis at the center. In the frame 23 of the base member 11, a PSD holder fixing hole 25 for fixing the PSD holder 14, a lens barrel fixing hole 26 for fixing the base member 11 to the lens barrel 3, and a connection between the base member and the first stage. A pressing spring hook 27 for fixing the pressing spring suspended therebetween is provided.
[0021]
As shown in FIGS. 2 and 3, in order to connect the imaging unit B to the optical unit A so that the position with respect to the lens barrel 3 (the tilt and the lens back) can be adjusted, the base member 11 includes the lens barrel 3. Are fixed by an adjusting screw 33 and an adjusting spring 21 between the three fixing portions 20 which are formed on the bottom surface of the. The distance and the inclination between the base member 11 and the bottom surface of the lens barrel 3 can be adjusted by the adjusting spring 21 used for the fixing portion 20, and as a result, the optical axis between the optical unit A and the imaging unit B can be adjusted. it can.
[0022]
A rod support arm 29 and a positioning arm (not shown) are erected on the base member 11 in the Z-axis direction. The rod support arm 29 is provided with a first actuator having a configuration in which a piezoelectric element 57 is fixed to the end of the vibration transmission rod 28 and the weight 30 is fixed to the other end of the piezoelectric element 57. In the first actuator, with the weight 30 in contact with the positioning arm, in the direction in which the vibration transmission rod 28 extends in the X-axis direction, the vicinities of both ends of the vibration transmission rod 28 are fitted to the rod support arm, and the base member 11 is fixed. For the adhesion between the rod support arm 29 and the vibration transmission rod 28, it is preferable to use an adhesive such as a silicon adhesive that remains elastic after curing. For the adhesion between the positioning arm and the weight 30, a soft rubber-based or silicone-containing adhesive is preferably used.
[0023]
As shown in FIG. 4, the two rod supporting arms 29 of the base member 11 are provided with protrusions 84 extending on the upper surface thereof in the Z-axis direction. As will be described later, the projection 84 is fitted into the movement restriction hole 52a of the first stage 13 during assembly.
[0024]
The first stage 13 is disposed downstream of the base member 11 in the optical axis direction (Z-axis direction). The first stage 13 is constituted by an aluminum rectangular frame 52 provided with an opening 51 for accommodating the second stage 12 in substantially the same plane. The first stage 13 includes a first rod contact portion 53 that contacts the vibration transmission rod 28 of the first actuator 59 fixed to the base member 11 and a vibration of a second actuator 44 fixed to a second stage described later. There is provided a second rod contact portion abutting on the transmission rod 47, a pressing spring hook for locking the pressing spring 55 between the pressing spring hook 27 of the base member 11, and a movement limiting hole 79.
[0025]
The first rod contact portion, together with the cap 32 and the spring 31, which are separate members, sandwiches the vibration transmission rod 28 of the first actuator 59 from above and below, and is slidably coupled to the first actuator along the vibration transmission rod 28. . One end of the cap 32 is locked to the first stage, the center portion is in contact with the vibration transmission rod 28, and the other end is fixed to the first rod contact portion of the first stage by being pulled by the holding spring 31. You. The contact pressure between the cap 32 and the vibration transmission rod 28 is about twice the force of the holding spring 31. The holding spring 31 is a torsion coil spring. The sandwiching spring 31 bridges both arms and the central arc portion between the two hooks of the cap 32 and the spring hook of the first stage 13, respectively.
[0026]
The movement restriction hole is loosely fitted with the protrusion 84 at the tip of the rod support arm 29 of the base member 11 as described above (see FIG. 4). The movement limiting hole 52a is a long hole extending in the movement direction (X-axis direction) to determine the amount of movement of the first stage 13, and the short side direction (Y-axis direction) so that the first stage can move only in the X-axis direction. Direction), and movement is regulated at both ends. In addition, the vibration transmission rod 28 and the first stage 13 are prevented from moving (falling) in the short side direction (Y-axis direction) of the movement restriction hole.
[0027]
As shown in FIG. 5, at the time of assembly, the first stage 13 is moved in a direction approaching the base member 12 by the pressing springs 55 provided on the base member 11 and the pressing spring hooks 27 and 56 provided on the first stage 13, respectively. The first stage 13 is biased to prevent the first stage 13 from rotating around the vibration transmission rod 28 of the first stage 13.
[0028]
The second stage 12 is a conductive resin box 40 having an opening 41 at the bottom, and holds the image sensor 15, the heat radiating plate 16, the low-pass filter 65, and the second actuator 44. The heat radiating plate 16 is fixed to the second stage so as to abut on the rear side of the imaging element 15 where the imaging surface is not provided, and to cover the opening defined by the peripheral wall 40 of the second stage. The low-pass filter 65, which is located in close contact with the image sensor 15 via the interval frame in front of the image sensor 15, is pressed against the heat radiating plate 16 by a contact spring from the front.
[0029]
The second stage 12 holds the second actuator 44. The second actuator 44 is adhesively held by a support arm 45 provided on the side of the box 40. The tip and the end (the piezoelectric element 55 side) of the vibration transmission rod 47 are axially fitted to the two rod supporting arms of the second stage 12, and are attached to the positioning surface 45a (see FIG. 3) also provided on the second stage. The weight 46 is adhered to the second stage 12 with the weight 46 in contact with the second stage 12. Similar to the bonding of the first actuator 59 described above, the bonding of the vibration transmission rod 60 is performed by using an adhesive such as a silicon adhesive that remains elastic after being cured, and the contact of the weight 58 is performed using a soft rubber or silicon. A contained adhesive is preferably used.
[0030]
The second actuator 44 of the second stage 12 is held between the second rod contact portion 54 of the first stage 13 and the cap 48. As a result, the second stage 12 is frictionally coupled with the second stage 12 being disposed in the opening 51 of the first stage 13. A holding spring 49 is used to fix the second rod contact portion 54 and the cap 48. One end of the cap 48 is locked to the second rod contact portion 54, the center portion contacts the vibration transmission rod 47, and the other end is pulled by the holding spring 49. The contact pressure between the cap 48 and the vibration transmission rod 47 is about twice as large as the holding spring 49 used. The holding spring 49 is a torsion coil spring similar to that used for the first actuator 59. The pinching spring 49 fixes both ends of the cap 48 and the center of the straight portion between the two hooks of the cap 48 and the spring hook of the second rod contact portion 54 of the first stage, respectively.
[0031]
The second stage 12 has a direction reference portion 42 made of metal on a part thereof. The direction reference portion 42 is in contact with the base member 11 and the first stage 13 via hard balls 43 on the front and back thereof, respectively. Since the pressing spring 55 is hung between the first stage 13 and the base member 11, the two stages 12, 13 are suppressed from rotating about the vibration transmitting rods that are frictionally coupled to each other.
[0032]
As shown in FIGS. 3 to 5, a first substrate 17 is provided on the back surface of the heat sink 16. The imaging device 15 has the terminal portion 69 disposed on the first substrate 17 through the through hole 68 of the heat sink 16. On the back side of the first substrate 17, an LED holder 70 accommodating two infrared LEDs 82X and 82Y for detecting the position of the image sensor 15, an image sensor driver, and a device for processing photoelectric signals from the image sensor. A part of an image signal output circuit of an image sensor, such as a preamplifier, a color separation circuit, a white balance adjustment circuit, and an analog processing circuit, is mounted.
[0033]
Further, the first substrate 17 is connected to the terminal section 69 of the CCD, and the CCD and the low-pass filter are fixed to the second stage. The first substrate 17 is connected to a flexible substrate 67 that connects the imaging device 15 and the second substrate 18. As shown in FIG. 7, the flexible substrate 67 is connected not only to the first substrate 17 but also to the heat radiating plate 16 so that the heat radiating plate 16 is grounded. Specifically, the flexible substrate 67 has a branch portion 87 provided in the vicinity of the terminal 88 connected to the first substrate 17, and the branch portion 87 has a through hole provided in the first substrate 17. It passes through and is connected to the radiator plate 16 located below. As a result, the second stage 12, the hard sphere 43, and the base member 11 that are in contact with the heat sink 16 are also grounded. Immediately after exiting the first substrate 17 in the horizontal direction, the flexible substrate 67 is once bent forward in the optical axis direction, is folded near the base member 11, and is again horizontally folded at the position of the second substrate 18, Connected to the second substrate 18.
[0034]
The PSD holder 14 is disposed on the base member 11 and mounts two position detecting elements (first and second PSDs 62X and 62Y) for detecting the amount of movement of the second stage 12 (that is, the first substrate 17). As shown in FIG. 4, a protrusion 83 is provided on the inner wall of the PSD holder 14 so as to cover a part of the first stage 13 from the PSD holder 14, and the first stage 13 falls off in the optical axis direction. To prevent
[0035]
The dustproof cap 19 is composed of a peripheral wall 19a and a bottom wall 19b, and is a cylindrical body closed on one side. The dustproof cap 19 has a bottom surface of the barrel unit so as to include the above-described image sensor 15 and its driving mechanism by a screw fixing hole 73a provided in a lower portion of the peripheral wall 19a and a cap fixing hole 25a in the bottom surface 3a of the barrel. To be fixed. The upper surface 19b of the dustproof cap has a small opening 74 through which the flexible substrate 67 passes, so that the flexible substrate connected to the first substrate can be connected to a second substrate (not shown) existing outside the dustproof cap. I have. Further, in order to further improve the sealing performance of the small opening 74, a sealing member for sealing the small opening is provided. Specifically, the small opening 74 is folded using a tape or the like in a folded state. The part 74 is closed.
[0036]
FIG. 6 is an enlarged view of a main part showing an arrangement relationship between an LED and a PSD in the imaging device of FIG. As described above, the two infrared LEDs 82X and 82Y are held by the LED holder 70 such that the moving surface of the first substrate 17 and the emitted light beam are parallel. Slits 71X and 71Y are provided in the LED holder 70 at positions separated from the LEDs 82, and light emitted from each LED 82 is converted into a linear light source by passing through the slits 71X and 71Y. Each LED 82 is provided with a lens in order to increase the directionality of the luminous flux. However, since the light emission direction is parallel to the moving plane of the first substrate as described above, the light intensity of the required spot diameter can be increased, Even if the distance is increased, a sufficient output can be obtained. As a result, as described later, even if the distance between the LED and the PSD changes, the accuracy of position detection does not change.
[0037]
Since the LED holder 70 is disposed on the first substrate 17 so that the slits 71X and 71Y are along the outer periphery of the heat sink 16 (first substrate envelope), most of the optical path emitted from the LEDs 82X and 82Y is the heat sink 16 (The first substrate envelope). Therefore, the space for the optical path can be saved.
[0038]
The two PSDs 62X and 62Y respectively corresponding to the two LEDs 82X and 82Y are held by the PSD holder 14 as described above. The PSD holder 14 is provided with arrangement portions 61X and 61Y for holding the respective PSDs 62X and 62Y. The PSDs 62X and 62Y incorporated in the arrangement portions 61X and 61Y are fixed by clips 63.
[0039]
The light receiving surfaces of the PSDs 62X and 62Y are orthogonal to the luminous fluxes of the corresponding two LEDs 82X and 82Y by the slits 64X and 64Y extending in parallel to the XY plane provided on the arrangement portions 61X and 61Y of the PSD holder 14.
[0040]
FIG. 7 is a conceptual diagram illustrating the state of light emission from the LED in FIG. The luminous fluxes X and Y emitted from the two LEDs 82X and 82Y respectively advance so as to intersect with each other at the gap 60 of the LED holder. The space 60 occupied by the optical paths for the two light beams X and Y overlaps, and this space can be reduced. The luminous fluxes X and Y pass from the slits 71X and 71Y provided in the LED holder 70, pass through the slits 64X and 64Y provided in the PSD holder 14, and reach the corresponding PSDs 62X and 62Y.
[0041]
Here, when the first substrate 17 moves together with the second slider 12, the distance between the LEDs 82X, 82Y and the PSDs 62X, 62Y changes. However, as described above, the LEDs 82X, 82Y increase the directionality of the light flux. Since the lens is provided, the intensity of the luminous flux does not change significantly even if the distance changes, and the accuracy of position detection by the PSDs 62X and 62Y does not change.
[0042]
Next, a modified example regarding the arrangement of the LED and the PSD will be described. FIG. 8A is a schematic diagram showing an arrangement relationship between the LED and the PSD shown in FIG. FIG. 8B is a schematic diagram illustrating an arrangement relationship between an LED and a PSD according to a modification. In the above embodiment, as described above, the light beams X and Y emitted from the LED are emitted in parallel to the first substrate 17 and directly enter the PSD as it is. In the modified example, a prism 91 is arranged in the middle of the optical path to refract the light beam in the Z-axis direction, and the PSD is arranged so that the light receiving surface faces the Z-axis direction. By refracting the light fluxes X and Y in this manner, the optical path length can be increased, and the accuracy of position detection can be further improved.
[0043]
Next, an operation of the camera shake correction of the imaging apparatus according to the present embodiment will be described. FIG. 9 is a block diagram illustrating an electrical structure of a drive control circuit of the camera shake correction imaging apparatus according to the present embodiment.
[0044]
The control circuit detects the position of the gyro element 90 for detecting the shake 5 of the optical axis L incident on the camera body, that is, the lens barrel 3 and outputting an angular velocity signal, and the PSD 62X for detecting the positions of the second stage 12 (imaging element 15). The microcomputer 102 includes a microcomputer 102 that performs comprehensive control of 62Y and calculates a movement amount and a position based on an input signal, and a drive circuit 104 that generates a drive pulse of a predetermined frequency based on a drive signal from the microcomputer. Is done. The drive pulse generated from the drive circuit is output to the first and second actuators 30, 46, and the first and second stages 12, 13 move along the actuators.
[0045]
The gyro element 90 is fixed to the lens barrel 3. When the camera body is shaken as shown by an arrow 5, the gyro element 90 detects angular velocities in two axial directions (X-axis direction, Y-axis direction) and outputs the angular velocity to the microcomputer 102.
[0046]
When the angular velocity signal is input from the gyro element 90, the microcomputer 102 calculates the moving amount and the moving speed of the image due to the blur on the image sensor (on the image plane) from the focal length signal of the optical system. From the calculated moving speed and the position of the second stage 12 (imaging element 15), a supply voltage of a predetermined frequency applied to the two linear actuators is determined. That is, the microcomputer 102 receives the light from the LEDs 82X and 82Y, calculates the position where the second stage 12 (imaging element 15) is present based on the signals output from the PSDs 62X and 62Y, and outputs the position from the gyro element 90. Based on the input angular velocity signal, the image sensor 15 calculates the position where it should be, compares the difference with the current position, and performs feedback control to move the stage so that the image sensor 15 returns to the position where it should be. Do.
[0047]
The drive circuit 104 receives a signal from the microcomputer 102 and outputs a drive pulse having a frequency of about 70% of the resonance frequency of the actuators 30, 46. The driving pulse is applied to the piezoelectric elements 57 and 55, and moves the first and second stages along the vibration transmission rods 28 and 47 according to the following principle.
[0048]
When a sawtooth drive pulse having a gradual rise 110 and a sharp fall portion 112 as shown in FIG. 10A is applied to the piezoelectric elements 57 and 55, the drive pulse becomes gradual as shown in FIG. In the rising portion 110, the piezoelectric elements 57 and 55 are gently extended and displaced in the thickness direction, and the vibration transmitting rods 28 and 47 fixed to the piezoelectric elements are gently displaced in the axial direction. At this time, the stages 12, 13 frictionally coupled to the vibration transmission rods 28, 47 move together with the vibration transmission rods 28, 47 due to the frictional force.
[0049]
On the other hand, in the sharp falling portion 112 of the drive pulse, the piezoelectric elements 57 and 55 are rapidly contracted and displaced in the thickness direction, and the vibration transmitting rods 28 and 47 connected to the piezoelectric elements 57 and 55 are also rapidly displaced in the axial direction. . At this time, as shown in (b3), the stages 12, 13 frictionally coupled to the vibration transmitting rods 28, 47 overcome the frictional coupling force due to the inertial force and substantially stay at that position and do not move. As a result, the stage moves rightward from the initial state shown in (b1). By continuously applying the driving pulse of the sawtooth wave to the piezoelectric elements 57 and 55, the stages 12, 13 can be continuously moved in the axial direction. Here, the phrase “substantially stays at the position and does not move” means that the vibration transmission rods 28, 47 are moved between the stages 12, 13 and the vibration transmission rods 28, 47 regardless of whether the vibration transmission rods 28, 47 extend or contract in the negative direction. The stage moves while sliding, but the movement amount is not symmetrical, and thus includes the case where the stages 12 and 13 move in any arbitrary direction as a whole.
[0050]
In order to move the stages 12 and 13 to the left, the waveforms of the sawtooth waves applied to the piezoelectric elements 57 and 55 are changed to apply a drive pulse consisting of a rapid rise and a gentle fall. This can be achieved by the opposite action. Note that a square wave or another waveform can be applied to the drive pulse.
[0051]
When a drive pulse is applied to the piezoelectric element 57 of the first actuator held by the base member 11, the piezoelectric element 57 repeats expansion and contraction as described above. The expansion and contraction of the piezoelectric element 57 is transmitted to the weight 30 and the vibration transmission rod 28. Due to the difference in the inertial mass between the weight 30 and the vibration transmission rod 28, the weight 30 hardly moves, and the expansion and contraction is transmitted only to the vibration transmission rod 28. The vibration transmission rod 28 is adhered to the rod support arm 29 as described above, but the adhesive is elastically bent, so that expansion and contraction is not hindered. As described above, the first stage 13 that is frictionally coupled with the speed difference moving right and left of the rod moves in the X-axis direction along the vibration transmission rod 28. As the first stage 13 is accelerated or decelerated, a force is applied to the first actuator 59 to move within the fitting play. However, since the vibration transmission rod 28 and the rod support arm 29 are adhered, no movement occurs. In addition, it is possible to prevent not only the correction performance but also the optical performance deterioration due to the focus movement.
[0052]
When the first stage 13 moves in the X-axis direction, the second stage 12 connected to the first stage also moves in the X-axis direction. The second stage 12 is moved by the pressing spring 55 between the first stage 13 and the base member 11 and the rigid ball 43 between the second stage 12 and the base member 11 with little resistance and without rattling in the optical axis direction. I do. At this time, since the optical path Y of the second LED 82Y on the first substrate 17 moves in the detection direction with respect to the second PSD 62Y orthogonal to the imaging surface of the imaging device, a change in position due to the second PSD 62Y is detected. Since the first LED 82X moves in the optical path X direction with respect to the first PSD 62X, a change in position due to the first PSD is not detected.
[0053]
On the other hand, when a drive pulse is applied to the piezoelectric element 58 of the second actuator 44 held on the second stage 12, the piezoelectric element 58 repeats expansion and contraction as described above. The expansion and contraction of the piezoelectric element 58 is transmitted to the weight 46 and the vibration transmission rod 47. Due to the difference in the inertial mass between the weight 46 and the vibration transmission rod 47, the weight 46 hardly moves, and the expansion and contraction is transmitted only to the vibration transmission rod 47. As described above, the vibration transmission rod 47 is bonded to the rod support arm 45 of the second stage 12, but the adhesive is elastically bent so that expansion and contraction is not hindered. As described above, the second stage 12 moves (self-propelled) in the extending direction (Y-axis direction) of the vibration transmission rod 47 with respect to the first stage 13 due to the speed difference of moving the rod left and right. As the second stage 12 is accelerated or decelerated, a force is applied to the second actuator 44 to move within the fitting play. However, since the vibration transmitting rod 47 and the rod support arm 45 are adhered, they cannot move. Therefore, it is possible to prevent not only the correction performance but also the optical performance deterioration due to the focus movement.
[0054]
When the drive pulse is applied to the second actuator 44 in this manner, only the second stage 12 moves (self-runs) in the Y-axis direction independently of the first stage 13. The second stage 12 has a low resistance and a play in the optical axis direction due to the pressing spring 55 applied between the first stage 13 and the base member 11 and the hard sphere 43 between the second stage 12 and the first stage. Move without sticking. At this time, since the first LED 82X on the first substrate 17 moves in the detection direction with respect to the first PSD 62X whose optical path X is orthogonal to the imaging surface of the imaging device, a change in position due to the first PSD is detected. Since the second LED 82Y moves in the optical path Y direction with respect to the second PSD 62Y, a change in position due to the second PSD is not detected.
[0055]
Grease having adhesive properties is applied to the first and second actuators 59 and 44 at the contact portions between the vibration transmission rods 28 and 47 and the two rod contact portions 53 and 54 of the first stage 13. By applying grease to the contact portion, the polishing powder generated when the rod contact portion and the vibration transmission rod 28 are repeatedly polished during use does not scatter due to the adhesive property of the grease, and the dust is imaged by the image sensor 15 as dust. It can be prevented from adhering to the surface.
[0056]
As described above, according to the imaging apparatus of the present embodiment, the LED for detecting the position of the stage and the PSD are arranged so as to have an optical path parallel to the moving direction of the stage. Even if it is necessary to shorten the distance in the Z-axis direction between the lens barrel and the imaging surface of the imaging device due to the matching of the design of the LED, the PSD and the PSD regardless of the distance between the base member 11 and the slider. The arrangement position can be determined. Therefore, the distance between the two elements can be increased, and both accuracy and detection range can be achieved. In addition, since the respective LEDs are arranged so that the emitted light beams intersect, the space for the optical path from the LEDs can be reduced, and the device can be made compact.
[0057]
Further, since the LED and the PSD are provided fixed to the holders 70 and 14, respectively, it is possible to reduce a mounting error at the time of mounting the device and the device, and to improve detection accuracy. Therefore, the present invention can be suitably used for movement / position detection in which the image sensor is moved for camera shake correction or pixel shift requiring a high detection accuracy.
[0058]
Next, a second embodiment of the imaging device of the present invention will be described. FIG. 10 is an exploded perspective view of the imaging apparatus according to the second embodiment of the present invention. The imaging device according to the present embodiment has substantially the same structure as the imaging device according to the first embodiment, and different components will be mainly described.
[0059]
The imaging device includes two units, an optical unit and an imaging unit. In the lens barrel 3 of the present embodiment, a fixing part 20 for attaching the imaging unit is provided around the lens barrel. The two units are fixed by adjusting their positions (tilt and lens back). The fixing portions 20 and the springs 21 provided at three places adjust the distance between the optical unit and the imaging unit.
[0060]
The base member 11, the first stage 13, the second stage 12, and the PSD holder 14a that support and swing the image sensor are located around the image sensor 15 (including the first substrate 17) and are located on the outer surface of the bottom surface 3a of the lens barrel 3. It is arranged so as to fill a surplus space on the outer periphery of the imaging element 15.
[0061]
The base member is a metal frame having a large hole 24 for the optical axis at the center. The frame 23 of the base member 11 is provided with a PSD holder fixing hole 25 for fixing the PSD holder 14a, a lens barrel fixing hole 26 for fixing the base member 11 to the lens barrel 3, and the like. A rod support arm extending in the Z-axis direction is provided upright from the base member, and the distal end and the end of the vibration transmission rod of the first actuator 59 are fixed to the two rod support arms by shaft fitting.
[0062]
The first stage 13 and the second stage have the same structure as the imaging device according to the first embodiment. That is, the first stage 13 moves with respect to the base member 11 in the X-axis direction, and the second stage 12 moves with respect to the first stage 13 in the Y-axis direction. Therefore, as a result, the imaging element 15 fixed to the second stage can move on the XY plane with respect to the base member.
[0063]
The PSD holder 14a is connected to the base member and is fixed to the base member 11 so as to surround the first stage 13, the second stage 12, and the image pickup device 15 (including the heat radiating plate 16 and the substrate 17). Two elements (first and second PSDs 62X and 62Y) for detecting the amount of movement of the stage are mounted. The light receiving surfaces of the PSDs 62X, 62Y are orthogonal to the light beams of the two LEDs 82X, 82Y on the second stage 13 by slits provided in the arrangement portions 61X, 61Y and extending horizontally on the XY plane.
[0064]
The second substrate 18 is located on the back side of the imaging surface, is fixed to the PSD holder 14a so as to cover the back opening of the PSD holder 14a, and is connected to the first substrate 17 by the flexible substrate 67. That is, the base member 11, the PSD holder 14a, and the second substrate 18 have a structure in which the image sensor 15 and its driving mechanism are hermetically enclosed except for the optical path and the moving space.
[0065]
On the second substrate 18, a circuit for processing a signal from the image sensor 15 or the first substrate 17, a position signal of the second stage from the PSD, and a circuit for controlling two linear actuators from a gyro circuit are mounted. . Two gyro signals whose detection directions are orthogonal to each other are input to the second substrate from a gyro substrate (not shown). Also, a linear actuator control signal and a processed image sensor signal are output from the second substrate.
[0066]
As described above, according to the imaging device according to the present embodiment, the PSD holder 14a that holds the PSD is also used as a sealing member of the imaging device. Dust prevention measures can be taken.
[0067]
Note that the present invention is not limited to the above embodiments, and can be implemented in various other modes. For example, in each of the embodiments described above, the LEDs are provided in the X-axis and Y-axis directions, respectively. It can also be configured to support one PSD.
[0068]
Further, instead of the PSD, a CCD, a MOS sensor, or the like can be used for the light receiving unit.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a digital camera using an imaging device of the present invention.
FIG. 2 is an exploded perspective view of the imaging device according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view of the imaging device of FIG. 2 taken along a line II.
FIG. 4 is a cross-sectional view of the imaging device of FIG. 2 cut along a II-II cross section.
5 is a cross-sectional view of the imaging device of FIG. 2 cut along a III-III cross section.
FIG. 6 is an enlarged view of a main part showing an arrangement relationship between an LED and a PSD in the imaging device of FIG. 2;
FIG. 7 is a conceptual diagram illustrating light emission of a light beam from the LED of FIG. 6;
FIG. 8A is a schematic diagram illustrating an arrangement relationship between the LED and the PSD illustrated in FIG. 2; FIG. 8B is a schematic diagram illustrating an arrangement relationship between an LED and a PSD according to a modification.
FIG. 9 is a block diagram illustrating an electrical structure of a drive control circuit of the camera shake correction imaging apparatus in FIG. 2;
FIG. 10 is a diagram for explaining the driving principle of the actuator. (A) is an example of the waveform of the drive pulse applied to the piezoelectric element. (B) is a diagram for explaining the movement of the actuator.
FIG. 11 is an exploded perspective view of an imaging device according to a second embodiment of the present invention.
[Explanation of symbols]
A optical unit B imaging unit (table device)
X, Y Optical path 1 Digital camera 2 Camera body 3 Optical unit 4 Lens 10 Imaging device 11 Base member 12 Second stage 13 First stage 14, 14a PSD holder 15 Imaging device 16 Heat sink 17 First substrate 18 Second substrate 19 Dustproof Cap 20 Fixing part 21 Adjusting spring 23 Frame 25 PSD holder fixing hole 44 Second actuator 59 First actuator 62X, 62Y PSD
67 Flexible board 70 LED holder 82X, 82Y LED

Claims (5)

A moving table that is arbitrarily movable with respect to the base member in two axial directions that are disposed opposite to the base member and that are not parallel to each other; and a position of the moving table in the two axial directions that includes a light emitting unit and a light receiving unit. A table device comprising a pair of position sensors
In each of the position sensors, one of the light emitting unit and the light receiving unit is disposed on a moving table, and an optical path between the light emitting unit and the light receiving unit is parallel to a moving plane of the moving table and respectively. Wherein the optical paths are provided so as not to be parallel to each other. The table device according to claim 1, wherein each of the position sensors is arranged such that respective optical paths intersect. The table device according to claim 1, wherein the light emitting units of the respective position sensors are respectively arranged in one light emitting side holder. The table device according to any one of claims 1 to 3, wherein the light receiving units of the position sensors are respectively arranged in one light receiving side holder. An imaging apparatus, wherein the table device according to any one of claims 1 to 4 is used as movement / position detection means of an imaging element.

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