Image stabilization control circuit, imaging device, and piezoelectric actuator drive circuit

• US 20090152985A1
• Filed: 12/15/2008
• Published: 06/18/2009
• Est. Priority Date: 12/18/2007
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Sanyo Semiconductor Company Limited (ON Semiconductor Corporation), Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Yamada, Yoshihisa, Kamiya, Tomonori
• Granted Patent: US 8,058,770 B2
• Time in Patent Office: Days
• US Class Current: 310/317
• CPC Class Codes: G02B 27/646 compensating for small deviations, e.g. due to vibration or shake movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68
• CPC Class Codes: H02N 2/062 Small signal circuits; Means for controlling position or derived quantities, e.g. for removing hysteresis

Abstract

In a drive circuit for a piezoelectric actuator, it is possible to move a movement object to a target position rapidly and with good precision. Parameters for two types of drive pulses (PL1, PL2) having different duty ratios are stored in a register (28). A pulse generation circuit (26) is configured so as to be able to switch, based on a parameter stored in the register (28), between (PL1) having a large displacement step width of a lens (8), and (PL2) having a small displacement step width. The lens (8) can be rapidly moved through coarse movement by (PL1), and the lens (8) can be made to approach the target position with good precision through fine movement by (PL2).

Claims

1. An image stabilization control circuit comprising:

a vibration compensation signal generation unit for generating, based on an output signal of a sensor for detecting a vibration of an imaging device, a vibration compensation signal that is in accordance with an amount of displacement of the imaging device caused by the vibration;

a lens control unit for generating a signal for controlling driving of a drivable lens on the basis of the vibration compensation signal and an output signal of a sensor for detecting a drive position of the lens of the imaging device; and

a piezoelectric actuator drive circuit for generating, based on the output signal of the lens control unit, a square-waveform drive signal for driving a piezoelectric actuator for displacing the lens one step at a time;

wherein the piezoelectric actuator drive circuit has;

a duty storage unit for storing information for defining first and second duty states for producing displacements having mutually different step widths for a duty of the drive signal;

a drive signal generation unit for generating the drive signal of the first or second duty state on the basis of information stored in the duty storage unit; and

a control unit capable of controlling whether the generated drive signal is set to any of the first and second duty states and switching between displacing the lens through fine movement having a small step width, and displacing the lens through coarse movement having a large step width.

2. The image stabilization control circuit according to claim 1, wherein the piezoelectric actuator drive circuit has a switching level storage unit for storing a switching level that can be arbitrarily set;

wherein

the control unit controls the drive signal generation unit in accordance with a result of comparing the switching level and displacement amount of the lens, designates a state of the coarse movement when the displacement amount is larger than the switching level, and designates a state of the fine movement when the displacement amount is equal to or less than the switching level.

3. The image stabilization control circuit according to claim 1, wherein the duty storage unit, the drive signal generation unit, and the control unit comprise an ASIC;

and

the duty storage unit is housed within the ASIC and comprises a register in which stored content can be rewritten.

4. The image stabilization control circuit according to claim 2, wherein the duty storage unit, the switching level storage unit, the drive signal generation unit, and the control unit comprise an ASIC;

and

the duty storage unit and the switching level storage unit are housed within the ASIC and comprise registers in which stored content can be rewritten.

5. An imaging device comprising the image stabilization control circuit according to claim 1.

6. A piezoelectric actuator drive circuit for generating a square-waveform drive signal for driving a piezoelectric actuator for displacing an object one step at a time;

the piezoelectric actuator drive circuit comprising;

a duty storage unit for storing information for defining first and second duty states for producing displacements having mutually different step widths for a duty of the drive signal;

a drive signal generation unit for generating the drive signal of the first or second duty state on the basis of information stored in the duty storage unit; and

a control unit capable of controlling whether the generated drive signal is set to any of the first and second duty states, and switching between displacing the object through fine movement having a small step width and displacing the object through coarse movement having a large step width.