JP2008048387A - Imaging unit and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging unit which is suitable for incorporation into a small camera module or an optical pickup etc. , small and lightweight, easily assembled and hardly influenced by dust, and to provide an imaging apparatus. <P>SOLUTION: An imaging sensor chip is mounted on an actuator for moving the imaging sensor chip. Thus, the imaging unit and the imaging apparatus can be provided which are suitable for incorporation into a small camera module or an optical pickup etc., small and lightweight, easily assembled and hardly influenced by dust. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging unit and an imaging apparatus, and more particularly, to an imaging unit and an imaging apparatus that are mounted on an actuating unit for moving an imaging sensor chip by an imaging sensor chip.

  In recent years, with the spread of digital cameras, camera-equipped mobile phones, etc., miniaturization and high performance of camera modules have progressed, and even with small camera modules, high functions such as AF, zoom, and camera shake correction have become essential. . Accordingly, there is a demand for a small actuator for moving a lens and an image sensor in a camera module. In addition, actuators are continually being miniaturized in applications such as optical pickup correction driving for recording and reproduction of DVDs and the like.

  Small actuators that have made remarkable progress in recent years include, for example, linear actuators using a piezoelectric element as a drive source (SIDM: Smooth Impact Drive Mechanism), string-like shape memory alloys (SMA: Shape Memory Alloys), and polymer actuators. Things can be raised.

In particular, electrostatic actuators using microfabrication technology applying integrated circuit technology called MEMS (Micro Electro Mechanical Systems) technology have attracted attention. For example, an image sensor is moved using a comb-shaped electrostatic actuator. Thus, a method of correcting camera shake has been proposed (see, for example, Patent Document 1).
JP 2006-133730 A

  However, in the method of Patent Document 1, the imaging sensor chip is mounted in a sensor package, the sensor package is mounted on a flexible substrate, and the flexible substrate is mounted on a camera shake correction mechanism including a comb-shaped electrostatic actuator. Since the imaging sensor chip, sensor package, flexible substrate and electrostatic actuator are manufactured separately, the driven object driven by the electrostatic actuator becomes large and heavy, In order to ensure the strength, the electrostatic actuator must be increased in size, which is inappropriate for incorporation into a small camera module or an optical pickup.

  Also, nothing is shown about dust countermeasures for electrostatic actuators, but dust countermeasures are an indispensable item for comb-shaped electrostatic actuators, and it is necessary to seal the entire electrostatic actuator section, and a camera shake correction device However, there is a problem that the size is further increased.

In general, there are the following problems in reducing the size of an actuator.
1) Reduction of driving load (driven body mass, mechanism friction, electrical wiring, air convection, etc.).
2) Simplification of assembly.
3) Reduction of garbage.
Each is described below.

  1) In general, an actuator generates less force as its volume decreases. For example, in a camera shake correction mechanism of the type that moves the image sensor that is currently realized, the mass of the image sensor unit that is the driven body is about 3 g, even if it is light, and the friction of the mechanism, the load due to the spring, and the image sensor When the load of the flexible substrate for transmitting the electric signal from the outside to the outside is combined, the load is generally about 0.1N.

The volume of the actuator for driving these loads is as large as about 300 mm ³ . This size is fatal for an actuator for driving an imaging sensor unit of a small camera unit or an optical pickup. Therefore, in order to achieve these, it is essential to reduce the weight and load of the imaging sensor unit.

  2) For example, in a camera shake correction mechanism of a type that moves the image sensor that is currently realized, there are about 20 parts that constitute the actuator and the correction mechanism, and there are about the same parts where these parts are joined. . Considering mounting on a small camera unit or an optical pickup, it is extremely difficult to extend these joints accurately and in a short time by extension of the conventional technology, and improvement is indispensable.

  3) As described above, an electrostatic actuator is currently most commonly known as an ultra-small actuator. For example, the above-described comb-shaped electrostatic actuator includes a fixed comb tooth and a movable comb tooth. Since the interval is as narrow as about several μm, a sealed structure that prevents entry of dust on the order of microns is indispensable in order to guarantee the operation.

  The present invention has been made in view of the above circumstances, and provides an image pickup unit and an image pickup apparatus that are suitable for incorporation into a small camera module, an optical pickup, etc., are small and light, easy to assemble, and are not affected by dust. The purpose is to do.

  The object of the present invention can be achieved by the following constitution.

1. An imaging sensor chip;
In an imaging unit comprising a fixed substrate, a moving substrate, and an actuator that includes an actuator that moves the moving substrate relative to the fixed substrate.
The imaging unit, wherein at least a part of the back surface of the imaging sensor chip is fixed to the moving substrate.

  2. 2. The imaging unit according to 1, wherein the movable substrate is made of the same main material as the imaging sensor chip and is fixed to the imaging sensor chip by a direct joining technique.

  3. 3. The imaging unit according to 2, wherein the main material is silicon.

4). The actuator includes: a fixed comb fixed on the fixed substrate; a movable comb formed integrally with the movable substrate and nesting with the fixed comb; a beam formed integrally with the movable substrate; A beam fixing part for fixing a part of the beam to the fixed substrate;
When the electric field is applied between the fixed comb and the movable comb, the movable substrate is moved relative to the fixed substrate by an attractive force acting between the fixed comb and the movable comb. The imaging unit according to any one of 1 to 3.

  5. The actuator includes a beam integrally formed with the moving substrate, a beam fixing portion for fixing a part of the beam to the fixed substrate, and a piezoelectric body formed on the beam. 4. The imaging unit according to any one of items 1 to 3.

  6). The actuator includes a beam formed integrally with the moving substrate, a beam fixing portion for fixing a part of the beam to the fixed substrate, and a shape memory alloy formed on the beam. The imaging unit according to any one of 1 to 3.

  7). The actuator includes a beam integrally formed with the moving substrate, a beam fixing portion for fixing a part of the beam to the fixed substrate, and a polymer actuator formed on the beam. The imaging unit according to any one of 1 to 3.

  8). The imaging unit according to any one of 4 to 7, wherein at least a part of the constituent elements of the actuator is disposed on a back surface of the imaging sensor chip.

9. An imaging optical system;
An image pickup apparatus comprising the image pickup unit according to any one of 1 to 8.

  According to the present invention, by mounting the imaging sensor chip on the actuating part for moving the imaging sensor chip, it is small and light, suitable for incorporation into a small camera module or an optical pickup, and easy to assemble. Thus, it is possible to provide an imaging unit and an imaging apparatus that are not affected by dust.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments. In the drawings, the same or equivalent parts are denoted by the same reference numerals, and redundant description is omitted.

  First, a digital camera which is an example of an imaging apparatus according to the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing the configuration of a digital camera and camera shake correction means, and the principle of camera shake correction.

  As shown in FIG. 1, the camera shake correction means 10 is mounted on the digital camera 1 and used. The digital camera 1 includes a camera body 2 and a lens barrel 3 that is an optical system including a photographing lens 4 and the like. As will be described in detail with reference to FIG. 2 and subsequent figures, the camera shake correction means 10 incorporates an image sensor chip 16 such as a CCD and is attached to the end of the lens barrel 3.

  When the digital camera 1 is shaken up and down during shooting and the optical axis L incident on the lens barrel 3 is shifted up and down as shown by an arrow 5, the shake is detected by a camera shake sensor 20 such as a gyro sensor, The shift of the optical axis L is corrected by moving the imaging sensor chip 16 up and down as indicated by the arrow 6 in accordance with the output of the camera shake sensor 20. The same applies to the blur in the horizontal direction. Here, the camera shake correction means 10 functions as an imaging unit in the present invention.

  Next, a first embodiment of the actuating unit 100, which is a main part of the camera shake correction unit 10, will be described with reference to FIGS. First, the configuration of the camera shake correction unit 10 will be described. 2 is a schematic diagram of the camera shake correction unit 10 as viewed from the optical axis L side, and FIG. 3 is a cross-sectional schematic diagram of the camera shake correction unit 10 taken along the A-A ′ section of FIG. 2.

  2 and 3, the camera shake correction means 10 includes an imaging sensor chip 16, an actuating unit 100, a die frame 205, a lead frame 201, a package 203, a protective glass 204, and the like.

  In the first embodiment, the actuator unit 100 includes a fixed substrate 101, a moving substrate 102, a comb-shaped actuator 110, and the like. The actuator 110 includes a fixed comb 104 fixed to the fixed substrate 101, The movable substrate 102 includes a moving comb 105, a beam 103, a beam fixing portion 106, and the like, which are integrally formed with the moving substrate 102, and is manufactured by the above-described MEMS technology using silicon (Si) as a main material.

  MEMS technology refers to the field of producing microsensors and actuators and electromechanical structures in units of μm using micromachining technology applying integrated circuit technology. Micromachines manufactured by micromachining technology are: In addition to being able to realize a size of less than mm and precision of less than μm, and as shown in FIG. 2, a complicated mechanism such as a nested comb tooth shape can be simultaneously produced with high accuracy at the same time. It is inexpensive and does not require assembly or adjustment processes.

In the first embodiment, for example, a silicon oxide film (SiO ₂ ) called a sacrificial layer is selectively stacked on a fixed substrate 101 made of, for example, silicon (Si), and an impurity is doped at a high concentration thereon. The structure layer made of conductive silicon (Si) is stacked, the structure layer is etched, and the moving substrate 102, the beam 103, the fixed comb 104, the moving comb 105, and the beam fixing portion 106 are simultaneously manufactured. The sacrificial layer is removed, and the moving substrate 102, the beam 103, and the moving comb 105 are formed in a state of floating from the fixed substrate 101.

  That is, the moving substrate 102, the beam 103, and the moving comb 105 are in a floating state with a gap 161 between the moving substrate 102 and the fixed substrate 101, and are fixed to the fixed substrate 101 by the beam fixing portion 106 formed at the center of the beam 103. It is fixed. The fixed substrate 101 is fixed to the die frame 205 with an adhesive or the like.

  The sacrificial layer etching technique is described in, for example, [Toyota Central R & D Co., Ltd. “Sacrificial layer dry etching technique for MEMS” http: // www. tylabs. co. jp / japanes / tech / sys_mems. pdf # search = '% E7% 8A% A0% E7% 89% B2% E5% B1% A4' (searched on July 18, 2006)].

  The fixed comb 104 and the movable comb 105 have a nested comb-teeth shape, and are generated between the fixed comb 104 and the movable comb 105 by applying an electric field between the fixed comb 104 and the movable comb 105. The moving comb 105 moves in the direction of arrow 6 in FIG. The operation by applying an electric field to the fixed comb 104 and the moving comb 105 will be described with reference to FIG.

  The imaging sensor chip 16 is manufactured by a semiconductor manufacturing process using silicon (Si) as a main material. The imaging sensor chip 16 includes an imaging surface 16a and a bonding pad 16b on the surface thereof, and is on the moving substrate 102 of the actuating unit 100 manufactured by the above-described MEMS technology. The back surface of the imaging surface 16a of the imaging sensor chip 16 and the front surface of the movable substrate 102 are bonded by, for example, a direct bonding technique.

  Direct joining technology is a joining method that does not use an adhesive, and is a joining method that uses the attractive force between the surfaces of the same type of material. For strength, strain and inclination after joining, ease of joining, space saving, etc. Are better. In this example, since both the moving substrate 102 and the imaging sensor chip 16 are made of silicon, bonding by a direct bonding technique is possible, and the above-described advantages can be obtained. As for the direct bonding technology, for example, [National Institute of Advanced Industrial Science and Technology “Wafer Direct Bonding Technology” http: // stuff. aist. go. jp / takagi. hideki / waferbonding. html (searched on July 18, 2006)] and the like.

  A bonding wire 202 for transmitting a signal from the imaging sensor chip 16 to the lead frame 201 is stretched between the bonding pad 16 b of the imaging sensor chip 16 and the lead frame 201. Also, a bonding wire 202 is stretched between the fixed comb 104 and the moving comb 105 and the lead frame 201 in order to apply an electric field between the fixed comb 104 and the moving comb 105.

  The lead frame 201 is soldered to a circuit board (not shown), so that an image signal from the imaging sensor chip 16 and a signal for applying an electric field to the fixed comb 104 and the moving comb 105 can be transmitted and received.

  The bonding wire 202 is a gold (Au) or aluminum (Al) wire having a diameter of several tens of μm (for example, 25 μm or 15 μm). FIGS. 2 and 3 show a gold (Au) wire. It is an example. Usually, the bonding pad 16b side of the image sensor chip 16 is called a ball bond, and a method is adopted in which a gold (Au) wire that has been melted by heat to form a ball is pressed against the bonding pad 16b and connected. The 201 side is often referred to as a stitch bond, in which a connection is made by rubbing a gold (Au) wire against the lead frame 201 while applying ultrasonic waves.

  When the digital camera 1 is in the upright state shown in FIG. 1, the bonding wire 202 is drawn out in the vertical direction of the camera shake correction means 10, that is, in the vertical direction in FIG. Accordingly, the center of the imaging surface 16a of the imaging sensor chip 16 and the optical axis L due to the mass of the moving part such as the imaging sensor chip 16 and the moving substrate 102 using the spring property of the bonding wire 202 (so-called center deviation). Can be reduced.

  Further, by pulling out the bonding wire 202 in the direction perpendicular to the moving direction of the image sensor chip 16 in this way, it is possible to move the image sensor chip 16 by moving the bonding wire 202 in the same direction as the moving direction of the image sensor chip 16. Accumulation of strain and metal fatigue due to shaking of the bonding wire 202 can be reduced.

  Further, in order to equalize the load generated by the bonding wire 202 when the imaging sensor chip 16 moves, the spring property of the wire on the side where the bonding wire 202 is compressed and the side where it is pulled is made equal. In order to make the spring properties of the bonding wires 202 equal, the number, length, thickness, drawing angle of the bonding wires 202, or their combined force may be made equal.

  Further, in the camera shake correction operation, the movement amount of the image sensor chip 16 is about several tens μm to several hundred μm in width, although it naturally depends on conditions such as the angle of view of the photographing lens 4 and the pixel size of the image sensor. In the first embodiment, since the imaging sensor chip 16 moves in the direction of the arrow 6 with respect to the lead frame 201 in accordance with the camera shake correction operation, the bonding wire 202 is disconnected even if the imaging sensor chip 16 moves. It is necessary to prevent the bonding or disconnection.

  Therefore, after bonding the bonding wire 202 to the bonding pad 16b of the imaging sensor chip 16, the peak in the height direction of the wire comes close to the imaging sensor chip 16 (for example, as shown in FIG. Y is set to be smaller than half (X / 2) of the distance X between the bonding pad 16b of the image sensor chip 16 and the bonding position on the lead frame 201), and is half the maximum width of the movement amount of the image sensor chip 16. It is desirable to stretch it so that it is loosened.

  Further, as described above, with repeated movement of the imaging sensor chip 16, disconnection due to fatigue of the bonding wire 202 or disconnection of bonding may occur. In particular, it is considered that the stitch bond on the lead frame 201 side has more distortion due to stress at the time of bonding than the ball bond on the bonding pad 16b side, so that there is a high possibility of disconnection or disconnection. . In order to avoid this, as shown in FIG. 2 and FIG. 3, it is desirable to reinforce the bonding portion by applying potting 151 with silicon resin or the like to the bonding portion on the lead frame 201 side.

  Each component of the camera shake correction means 10 described above, specifically, the actuating unit 100, the imaging sensor chip 16, the die frame 205, the lead frame 201, and the bonding wire 202 are arranged at the tip of the die frame 205 and the lead frame 201. All but one part are sealed in a space created by the package 203 and the protective glass 204. The camera shake correction means 10 is assembled in a clean room or a clean bench, for example, and dust does not enter the space formed by the package 203 and the protective glass 204, and the actuator 100 and the image sensor chip are sealed by sealing. 16 can be protected from dust.

  In addition, since air convection is eliminated by sealing, variation in load due to air convection on the actuating unit 100 can be reduced.

  In this example, as shown in FIG. 3, the image sensor chip 16 and the actuating unit 100 are kept sealed by the protective glass 204, but as shown in FIG. 4, the photographing lens 4 is used instead of the protective glass 204. The lens 41 may be sealed by the lens 41 closest to the imaging sensor chip 16.

  Next, the operation of the camera shake correction unit 10 will be described. FIG. 5 is a timing chart showing an example of a driving method of the electrostatic actuator according to the first embodiment.

  2 and 5, the fixed comb 104 positioned on the + side of the arrow 6 is defined as a + side fixed comb 104p, and the fixed comb 104 positioned on the − side of the arrow 6 is defined as a − side fixed comb 104m. The beam fixing portion 106 is connected to a lead frame 201 formed integrally with the die frame 205 by bonding, and is grounded outside the package 203.

  As shown at timing T1 in FIG. 5, when an electric field of + E is applied to the + side fixed comb 104p, an attractive force is generated between the + side fixed comb 104p and the moving comb 105, and the moving comb 105, that is, the moving substrate 102, is generated. Moves in the + direction of arrow 6. At this time, the beam 103 whose center portion is fixed to the fixed substrate 101 is bent by the beam fixing portion 106, so that the beam 103 ensures movement of the moving substrate 102 only in the direction of the arrow 6. That is, the moving substrate 102 completely translates in the + direction of the arrow 6 and does not move in the direction perpendicular to the arrow 6.

  When the electric field applied to the + side fixed comb 104p is held at + E as at the timing T2, the moving substrate 102 stops due to the balance between the attractive force due to the electrostatic force and the force due to the bending of the beam 103. When the application of the electric field to the + side fixed comb 104p is stopped at timing T3, the attractive force due to the electrostatic force disappears, and the moving substrate 102 returns to the original position by the restoring force of the beam 103.

  Next, when an electric field of + E is applied to the −side fixed comb 104m at timing T4, an attractive force is generated between the −side fixed comb 104m and the moving comb 105, and the moving comb 105, that is, the moving substrate 102 is moved to the arrow 6 position. Move in the negative direction. Also at this time, the beam 103 is bent, so that the beam 103 ensures movement of the moving substrate 102 only in the direction of the arrow 6.

  When the electric field applied to the negative fixed comb 104m is held at + E as at the timing T5, the moving substrate 102 stops due to the balance between the attractive force due to the electrostatic force and the force due to the bending of the beam 103. At time T6, when the application of the electric field to the negative fixed comb 104m is stopped, the attractive force due to the electrostatic force disappears, and the moving substrate 102 returns to the original position by the restoring force of the beam 103.

  That is, the camera shake correction unit 10 can correct image degradation due to camera shake by applying an electric field to a fixed comb in a direction in which the moving substrate 102 is to be moved, and can stop the beam application by stopping the application of the electric field. The moving substrate 102 returns to the initial position by the restoring force 103.

  In the first embodiment, for the sake of simplicity, the configuration in which the movable substrate 102 is movable only in the direction of the arrow 6 (the left-right direction in FIG. 2) is illustrated, but this configuration is equivalent to this configuration. By disposing the configuration between the fixed substrate 101 and the die frame 205, the movable substrate 102 can also move in a direction perpendicular to the arrow 6 (vertical direction in FIG. 2).

  In the first embodiment, the portion of the moving substrate 102 that faces the back surface of the imaging sensor chip 16 is bonded to the entire surface imaging sensor chip 16. The projection area viewed from the optical axis L side can be made smaller than that shown in FIG. 2 by producing the beam 103, the fixed comb 104, and a part of the moving comb 105 in a part of the part facing the back surface of Is possible. An example in which this idea is further extended and all the actuating portions 100 are formed on the back surface of the imaging sensor chip 16 will be described later with reference to FIG.

  Further, in the first embodiment, the actuate unit 100 is manufactured by MEMS technology using silicon (Si) as a main material. However, the present invention is not limited to this. It may be the one that has been subjected to conductive processing by vapor deposition or the like, or the one in which a conductive plastic is finely molded.

  The camera shake correction means 10 configured as described above moves with the fixed comb 104 in accordance with the vibration amount and speed of the digital camera 1 due to a user's camera shake detected by the camera shake sensor 20 installed in the digital camera 1. By controlling the electric field E applied between the combs 105, the imaging sensor chip 16 mounted on the moving substrate 102 is moved, and the deviation of the optical axis L is corrected.

  As described above, according to the first embodiment, it is possible to manufacture a complex actuate part with high accuracy at the same time in a batch process by producing the actuate part by MEMS technology, and at low cost for assembly and adjustment. A process is also unnecessary. In addition, by mounting the imaging sensor chip on the actuating part, the imaging sensor chip and the actuating part can be coupled without using a package or mounting board, so the actuating part can be reduced in size. Therefore, it is possible to provide an imaging unit and an imaging apparatus that are suitable for incorporation into a small camera module, an optical pickup, and the like, are small and light, are easy to assemble, and are not affected by dust.

  Furthermore, by sealing the image sensor chip and the actuate part in the same package, it is possible to eliminate the effects of dust, and it is suitable for incorporation into small camera modules and optical pickups. Thus, it is possible to provide an imaging unit and an imaging apparatus that are not affected by dust. In addition, the actuation of the actuating unit is as simple as applying an electric field, and control is also easy.

  In addition, the imaging sensor chip is mounted on the actuating part by means of drawing out the bonding wire, loosening, and reinforcement by potting the bonding part. The imaging sensor chip and the actuating part are the same. It is possible to prevent disconnection of the bonding wire caused by moving the imaging sensor chip while being sealed in the package, which contributes to improvement in reliability.

  Next, a second embodiment of the actuate unit 100 will be described with reference to FIG. 6A and 6B are schematic views showing the configuration of the actuate unit 100 according to the second embodiment. FIG. 6A is a schematic view of the actuate unit 100 viewed from the optical axis L side, and FIG. 6A and 6C are schematic views of the BB ′ cross section, and FIG. 6C is a schematic view seen from the back side of FIG. 6A. In the second embodiment, the actuating unit 100 is configured on the back side of the imaging surface 16a of the imaging sensor chip 16, and the actuator 110 includes a fixed comb 504, a moving comb 505, a beam 503, a beam fixing unit 506, and the like. Consists of.

6A, 6B, and 6C, for example, a silicon oxide film (SiO ₂₎ called a sacrificial layer is formed on the back surface of the image sensor chip 16 manufactured by a semiconductor manufacturing process using, for example, silicon (Si) as a main material. ) Are selectively stacked, and a structure layer mainly composed of silicon (Si) is stacked thereon, and the structure layer is etched to form a moving substrate 502, a beam 503, a fixed comb 504, a moving comb 505, and a beam fixing portion 506. At the same time, the sacrificial layer is removed by sacrificial layer etching, and the moving substrate 502, the beam 503, and the moving comb 505 are formed so as to float from the back surface of the imaging sensor chip 16.

  That is, the moving substrate 502, the beam 503, and the moving comb 505 are in a floating state with a gap 561 between the back surface of the imaging sensor chip 16 and are imaged by the beam fixing portion 506 formed at the center of the beam 503. It is fixed to the back surface of the sensor chip 16. The moving substrate 502 is fixed to the fixed substrate 501 with an adhesive or the like.

  Note that, in the cross-sectional view of FIG. 6B, only the cross-sections of the moving substrate 502, the fixed comb 504, and the moving comb 505 are hatched for easy viewing of the drawing.

  The operation is the same as that shown in FIG. 5. The moving substrate 102 in FIG. 5 is read as the moving substrate 502, the fixed combs 104 p and 104 m are read as the fixed combs 504 p and 504 m, and the fixed comb 504 p or 504 m and the moving comb 505 are read. When an electric field E is applied to the fixed comb 504p or 504m and the moving comb 505, an attractive force is generated between the fixed comb 504p or 504m and the moving comb 505, and the fixed comb 504p or 504m and the moving comb 505 attract each other. The positional relationship between the imaging sensor chip 16 to which the moving comb 505 is fixed and the fixed substrate 501 to which the moving comb 505 is fixed relatively moves.

  The configuration of the fixed comb 504p or 504m and the moving comb 505 shown in FIG. 6C assumes that the imaging sensor chip 16 is moved in the vertical direction (direction of arrow 6) of the digital camera 1 shown in FIG. In the example, the number of comb teeth of the fixed comb 504p for moving the imaging sensor chip 16 upward against the mass of the imaging sensor chip 16 and the actuating unit 100 and the moving comb 505 opposed thereto is calculated. 16 and the number of comb teeth of the fixed comb 504m for moving the imaging sensor chip 16 in the downward direction, which is the action direction of the mass of the actuating unit 100, and the moving comb 505 opposed thereto.

  By mounting the fixed substrate 501 of the second embodiment on the moving substrate 102 of the first embodiment shown in FIG. 2, the vertical movement of FIG. 2 can be achieved according to the second embodiment. The imaging sensor chip 16 can be moved two-dimensionally by realizing and moving in the left-right direction in FIG. 2 according to the first embodiment.

  Further, on the image sensor chip 16 or the fixed substrate 501, not only the above-described actuating unit 100 but also a position sensor for detecting the position of the image sensor chip 16 relative to the fixed substrate 501, or a shake of the digital camera 1 is detected. It is also possible to integrally configure functions that can be formed in the semiconductor manufacturing process, such as sensors such as the shake sensor 20.

  As described above, according to the second embodiment, the actuate portion can be further downsized than the first embodiment by producing the actuate portion on the back surface of the imaging sensor chip. It is also possible to realize a two-dimensional actuating unit in combination with the first embodiment or by making the second embodiment two-story. In addition, the actuation of the actuating unit is as simple as applying an electric field, and control is also easy. Furthermore, the optimal movement performance can be obtained by optimizing the number of comb teeth according to the load.

  Next, a third embodiment of the actuate unit 100 will be described with reference to FIG. FIG. 7 is a schematic view showing the configuration of the actuate unit 100 according to the third embodiment. FIG. 7A is a front view of the image pickup device 16 as viewed from the image pickup surface 16a side, and FIG. It is the side view seen from the arrow C side of 7 (a).

  In the first and second embodiments described above, the actuating part using the electrostatic force generated between the fixed comb 104 or 504 and the moving comb 105 or 505 is illustrated, but the actuating part is not limited to this. Instead, the actuating unit 100 may be configured by another driving mechanism that can be formed by the MEMS technology. Here, an actuating portion using the piezoelectric phenomenon of the piezoelectric thin film is illustrated.

  7A and 7B, for example, an image sensor chip 16 manufactured by a semiconductor manufacturing process using silicon (Si) as a main material has silicon (Si) doped with impurities at a high concentration as a main material. It is mounted on the moving substrate 302 and bonded by a direct bonding technique or a method such as adhesion. The moving substrate 302 is provided with two leg-shaped beams 303, and the moving substrate 302 and the beam 303 are separated from the fixed substrate 301 by a minute gap 361 and the beam fixing portion 306 is provided on the fixed substrate 301. It is fixed with.

  The fixed substrate 301 is made of silicon (Si), glass, or the like. A piezoelectric thin film 304 is formed on each of the two beams 303 of the moving substrate 302. As a method for forming the piezoelectric thin film, there are a sputtering method, a CVD method, a sol-gel method, and the like. In the third embodiment, the actuator 110 includes a beam 303, a beam fixing portion 306, a piezoelectric thin film 304, and the like, and the piezoelectric thin film 304 functions as a piezoelectric body in the present invention. The piezoelectric body is not limited to a piezoelectric thin film, and may be a normal single layer or multilayer piezoelectric actuator.

  The actuator unit 100 and the image sensor chip 16 shown in FIG. 7 are mounted on the die frame 205 in the package 203 and wire-bonded in the same manner as shown in FIGS. 204 or the lens 41 is sealed in the same space.

  An electrode is formed on the surface of the piezoelectric thin film 304. The moving substrate 302 is highly doped with impurities and has conductivity, and is grounded by a beam fixing portion 306. Since there are no inclusions such as an adhesive between the beam 303 and the piezoelectric thin film 304, the beam 303 serves as a common electrode of the piezoelectric thin film 304.

  Now, let the piezoelectric thin film 304 located on the + side of the arrow 6 in FIG. 7 be the + side piezoelectric thin film 304p, and the piezoelectric thin film 304 located on the − side of the arrow 6 be the − side piezoelectric thin film 304m. When a negative voltage is applied to the electrode of the + side piezoelectric thin film 304p, the + side piezoelectric thin film 304p contracts in a direction orthogonal to the arrow 6 so that the beam 303 is bent to the right in the figure, and the moving substrate 302 is moved in the + direction of the arrow 6 Moved. At this time, the beam 303 ensures movement of the moving substrate 302 only in the direction of the arrow 6. When the application of voltage to the + side piezoelectric thin film 304p is stopped, the movable substrate 302 returns to the original position by the restoring force of the beam 303. Since the width d of the beam 303 is very thin, about several μm to several tens of μm, it can be sufficiently driven by the driving force of the piezoelectric thin film 304.

  Next, when a negative voltage is applied to the negative side piezoelectric thin film 304m, the negative side piezoelectric thin film 304m contracts in a direction perpendicular to the arrow 6, so that the beam 303 is bent to the left in the figure, and the moving substrate 302 is moved in the negative direction of the arrow 6. Move to. Also at this time, the beam 303 ensures the movement of the moving substrate 302 in the direction of arrow 6 only. When the application of the voltage to the negative side piezoelectric thin film 304m is stopped, the moving substrate 302 returns to the original position by the restoring force of the beam 303.

  In the third embodiment, the example in which the piezoelectric thin film is used for the actuate portion has been described. However, the shape memory alloy (SMA) or the polymer actuator described above can be used instead of the piezoelectric thin film. Also in this case, a shape memory alloy thin film or a polymer thin film is formed at the position of the piezoelectric thin film 304 in FIG. 7, and heating by applying an electric current (in the case of shape memory alloy) or deformation by applying an electric field (polymer actuator In this case, the operation of the actuating unit may be controlled by controlling the current or electric field.

  In the third embodiment, the movable substrate 302, the beam 303, and the beam fixing portion 306 are manufactured by MEMS technology using silicon (Si) as a main material. However, the present invention is not limited to this. You may produce by processing a metal plate by an etching etc.

  As described above, according to the third embodiment, the moving substrate 302 including the beam 303 on the fixed substrate 301 is fixed by the beam fixing unit 306, and the piezoelectric thin film 304 is formed on the beam 303. In addition, the small actuating part 100 can be realized with a simple configuration, and the actuating part 100 can be driven simply by applying a voltage to the piezoelectric thin film 304 and can be controlled easily.

  As described above, according to the present invention, by mounting the imaging sensor chip on the actuating portion for moving the imaging sensor chip, it is suitable for incorporation into a small camera module, an optical pickup, etc. It is possible to provide an imaging unit and an imaging apparatus that are small and light, are easy to assemble, and are not affected by dust.

  It should be noted that the detailed configuration and detailed operation of each component constituting the imaging unit and the imaging apparatus according to the present invention can be changed as appropriate without departing from the spirit of the present invention.

It is a schematic diagram which shows the structure of a digital camera and camera shake correction means, and the principle of camera shake correction. It is the schematic diagram which looked at the camera shake correction means from the optical axis side. FIG. 3 is a schematic cross-sectional view of the camera shake correction unit taken along the A-A ′ cross section of FIG. 2. It is another example of the cross-sectional schematic diagram which cut the camera shake correction | amendment means in the A-A 'cross section of FIG. It is a timing chart which shows an example of the drive method of the electrostatic actuator in 1st Embodiment of an actuate part. It is a schematic diagram which shows the structure of 2nd Embodiment of an actuate part. It is a schematic diagram which shows the structure of 3rd Embodiment of an actuate part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 2 Camera body 3 Lens barrel 4 Shooting lens 7 Bending mirror 10 Camera shake correction means 16 Imaging sensor chip 16a Imaging surface 16b Bonding pad 20 Camera shake sensor 100 Actuate part 101 Fixed substrate 102 Moving substrate 103 Beam 104 Fixed comb 105 Moving comb 106 Beam fixing portion 110 Actuator 151 Potting 201 Lead frame 202 Bonding wire 203 Package 204 Protective glass 205 Die frame 301 Fixed substrate 302 Moving substrate 303 Beam 304 Piezoelectric thin film 306 Beam fixing portion 501 Fixed substrate 502 Moving substrate 503 Beam 504 Fixed comb 505 Movement Comb 506 Beam fixing part

Claims (9)

An imaging sensor chip;
In an imaging unit comprising a fixed substrate, a moving substrate, and an actuator that includes an actuator that moves the moving substrate relative to the fixed substrate.
The imaging unit, wherein at least a part of the back surface of the imaging sensor chip is fixed to the movable substrate. The imaging unit according to claim 1, wherein the moving substrate is made of the same main material as the imaging sensor chip and is fixed to the imaging sensor chip by a direct joining technique. The imaging unit according to claim 2, wherein the main material is silicon. The actuator includes: a fixed comb fixed on the fixed substrate; a movable comb formed integrally with the movable substrate and nesting with the fixed comb; a beam formed integrally with the movable substrate; A beam fixing part for fixing a part of the beam to the fixed substrate;
When the electric field is applied between the fixed comb and the movable comb, the movable substrate is moved relative to the fixed substrate by an attractive force acting between the fixed comb and the movable comb. The imaging unit according to any one of claims 1 to 3. The actuator includes a beam integrally formed with the moving substrate, a beam fixing portion for fixing a part of the beam to the fixed substrate, and a piezoelectric body formed on the beam. Item 4. The imaging unit according to any one of Items 1 to 3. The actuator includes a beam integrally formed with the moving substrate, a beam fixing portion for fixing a part of the beam to the fixed substrate, and a shape memory alloy formed on the beam. The imaging unit according to claim 1. The actuator includes a beam formed integrally with the moving substrate, a beam fixing portion for fixing a part of the beam to the fixed substrate, and a polymer actuator formed on the beam. The imaging unit according to claim 1. The imaging unit according to any one of claims 4 to 7, wherein at least a part of the constituent elements of the actuator is disposed on a back surface of the imaging sensor chip. An imaging optical system;
An imaging apparatus comprising: the imaging unit according to claim 1.

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