Camera module actuator
An actuator includes a magnet, a driving coil facing the magnet, a driver, and a position calculation processor. The driver is configured to move the magnet in at least one of an optical axis direction and a direction perpendicular to the optical axis by applying a driving signal to the driving coil. The position calculation processor includes sensing coils, and is configured to calculate a position of the magnet according to inductance levels of an inductor of the sensing coils. The inductance levels vary according to movements of the magnet.
1. An actuator, comprising:
a magnet;
a driving coil facing the magnet;
a driver configured to move the magnet in at least one of an optical axis direction and a direction perpendicular to the optical axis by applying a driving signal to the driving coil; and
a position calculation processor, comprising sensing coils, configured to calculate a position of the magnet, according to frequencies of oscillation signals generated by counting the frequencies of the oscillation signals using a reference clock, based on inductance levels of an inductor of the sensing coils that excludes a subset of the inductance levels having same increasing or decreasing directions of inductance levels,
wherein the inductance levels vary according to movements of the magnet.
2. The actuator of claim 1 , wherein the sensing coils are disposed in a direction of the movements of the magnet.
3. The actuator of claim 2 , wherein the position calculation processor calculates the position of the magnet according to the directions of the inductance levels of the sensing coils.
4. The actuator of claim 3 , wherein the position calculation processor calculates the position of the magnet according to the inductance levels of the sensing coils upon the directions of the increase and decrease in the inductance levels of the sensing coils being different from each other.
5. The actuator of claim 1 , wherein the position calculation processor outputs the inductance levels of the sensing coils as oscillation signals.
6. The actuator of claim 1 , wherein the position calculation processor calculates the position of the magnet based on the position of the magnet corresponding to the frequencies of the oscillation signals.
7. An actuator, comprising:
a magnet;
a driving coil facing the magnet;
a driver configured to move the magnet in at least one of an optical axis direction and a direction perpendicular to the optical axis by applying a driving signal to the driving coil; and
a position calculation processor comprising a sensing coil, wherein inductance levels of the sensing coil varies according to movements of the magnet,
wherein the sensing coil is disposed in a direction along the movements of the magnet, and
wherein the position calculation processor calculates a position of the magnet according to frequencies of oscillation signals generated based on changes in the inductance levels by counting the frequencies of the oscillation signals using a reference clock.
8. The actuator of claim 7 , wherein the driving coil and the sensing coil are formed by providing a conductive pattern to a substrate comprising layers.
9. The actuator of claim 8 , wherein the driving coil and the sensing coil are formed in different regions in a direction that the layers are stacked.
10. The actuator of claim 8 , wherein the driving coil and the sensing coil are formed in a same region in a direction that the layers are stacked.
11. The actuator of claim 10 , wherein the driving coil is formed in a portion of the layers, and the sensing coil is formed in another portion of the layers.
12. The actuator of claim 11 , wherein one of the layers, having the sensing coil formed therein, is disposed between layers each having the driving coil formed therein.
13. The actuator of claim 7 , wherein the sensing coil has at least one of circular shape, triangular shape, and quadrangular shape.
14. The actuator of claim 7 , wherein the position calculation processor calculates the position of the magnet, excluding changes in the inductance levels having same increasing or decreasing directions of inductance levels.
15. An actuator, comprising:
a magnet disposed on a side of a lens holder of a lens module;
a driving coil disposed on a substrate, facing the magnet, to move the lens module in an optical axis direction; and
a position calculation processor comprising sensing coils positioned on the substrate facing the magnet, wherein a change in magnitude of a magnetic field generated by the magnet varies an inductance of the sensing coils to determine a displacement of the lens module, and
wherein the position calculation processor calculates the position of the magnet, according to frequencies of oscillation signals generated by counting the frequencies of the oscillation signals using a reference clock, based on inductance levels of the inductance that excludes a subset of the inductance levels having same increasing or decreasing directions of inductance levels.
16. The actuator of claim 15 , wherein the sensing coils comprises two sensing coils disposed in the optical axis direction.
17. The actuator of claim 15 , wherein the sensing coils comprises two sensing coils disposed in a direction perpendicular to the optical axis direction.
18. The actuator of claim 15 , wherein the sensing coils comprises two sensing coils, in which an inductance level of one of the two sensing coils decreases and an inductance level of the other of the two sensing coils increases.
19. An actuator, comprising:
a magnet disposed on a side of a lens holder of a lens module;
a driving coil disposed on a substrate, facing the magnet, to move the lens module in an optical axis direction; and
a position calculation processor comprising sensing coils, positioned opposite to each other, on the substrate and opposite to the magnet, and configured to calculate frequencies of oscillation signals generated based on changes in inductance levels of the sensing coils by counting the frequencies of the oscillation signals using a reference clock,
wherein a change in a position of the magnet changes a resonance frequency of the sensing coils to determine a displacement of the lens module.
20. The actuator of claim 19 , wherein the position calculation processor comprises:
an oscillation processor comprising the sensing coils, a capacitor, and a resistor, wherein the oscillation processor is configured to generate oscillation signals to determine the resonance frequency thereof based on the inductance levels of the sensing coils,
an arithmetic processor configured to calculate the resonance frequency of the oscillation signals, and
a determination processor configured to determine the position of the magnet based on the resonance frequency of the oscillating signal.
21. The actuator of claim 20 , wherein a magnetic body having high magnetic permeability and a paint formed of a magnetic material are formed between the magnet and the oscillation processor to raise a rate of change in the inductance of the one of the sensing coils based on a change in the position of the magnet.
22. The actuator of claim 19 , wherein the position calculation processor calculates the position of the magnet according to frequencies of the oscillation signals generated on the basis of changes in inductance levels of the sensing coils.
23. The actuator of claim 19 , wherein the sensing coils have different shapes from each other, where the shapes include a circular shape, a triangular shape, and a quadrangular shape.