US 2009/0244668 A1 · METHOD OF DRIVING MEMS MIRROR SCANNER, METHOD OF DRIVING MEMS ACTUATOR SCANNER AND METHOD OF CONTROLLING ROTATION ANGLE OF MEMS ACTUATOR

Abstract

A method of driving a MEMS mirror scanner having an electrostatic actuator, comprising a step of driving the electrostatic actuator according to an input signal in accordance with a driving waveform obtained by the following equation, when C + ′  ( θ ) ≠ 0 V V  ( t ) = 1 C + ′  ( θ ) I [ - C - ′  ( θ ) I  V B + - ( 1 I   C L  ( θ )  θ )  ( 1 I   C R  ( θ )  θ )  V B 2 + C + ′  ( θ ) I  ( θ ¨ + 2  B I  θ . + κ I  θ ) ] when C + ′  ( θ ) = 0 V V  ( t ) = θ ¨ + 2  B I  θ . + κ I  θ 2  C - ′  ( θ ) I  V B where, B/I, κ/I, (1/I)·dCL(θ)/dθ and (1/I)·dCR(θ)/dθ are parameters for obtaining the driving waveform, θ(t) is a desired mirror angle response, I is a moment of inertia of a moving part including a mirror, 2B is a damping factor (damping coefficient), κ is a spring constant, CL(θ) and CR(θ) are angle dependencies of an electric capacitance, VB is a constant bias voltage in differential driving, and C+′(θ) and C−′(θ) are ½ of the sum and the difference of the first order derivative of CL(θ) and CR(θ) with respect to θ, respectively, which are represented by defined equations.

Claims22

Dependent claims

A method of driving a MEMS mirror scanner including an electrostatic actuator, comprising a step of driving the electrostatic actuator according to an input signal in accordance with a driving waveform obtained by the following equation,

when


C
+
′

(
θ
)
≠
0
V
V
(

t
)
=

1
C
+
′

(
θ
)
I
[

-
C
-
′

(
θ
)
I


V
B
+

-
(
1
I


C
L

(
θ
)

θ
)

(
1
I


C
R

(
θ
)

θ
)

V
B
2
+
C
+
′

(
θ
)
I

(
θ
¨
+
2

B
I

θ
.
+
κ
I

θ
)
]
when


C
+
′

(
θ
)
=
0


V
V

(
t
)
=
θ
¨
+
2

B
I

θ
.
+
κ
I

θ
2

C
-
′

(
θ
)
I

V
B
where B/I, κ/I, (1/I)·dCL(θ)/dθ and (1/I)·dCR(θ)/dθ are parameters to obtain the driving waveform, θ(t) is a desired mirror angle response, I is a moment of inertia of an moving part including a mirror, 2B is a damping factor (damping coefficient), κ is a spring constant, CL(θ), CR(θ) are angle dependencies of an electric capacitance, VB is a constant bias voltage in differential driving, and C+′(θ) and C−′(θ) are ½ of the sum and the difference of the first order derivative of CL(θ) and CR(θ) with respect to θ, respectively, which are represented by the following equations,
C
+
′

(
θ
)
=
1
2

(

C
L

(
θ
)

θ
+

C
R

(
θ
)

θ
)
,
(
8
)
C
-
′

(
θ
)
=
1
2

(
-

C
L

(
θ
)

θ
+

C
R

(
θ
)

θ
)
(
9
)

227 more elements

Dependencies are inferred from the claim text.

Method of driving mems mirror scanner, method of driving mems actuator scanner and method of controlling rotation angle of mems actuator

Life of this patent

Method of driving mems mirror scanner, method of driving mems actuator scanner and method of controlling rotation angle of mems actuator

Life of this patent

Abstract

Claims22