U.S. patent application number 13/626059 was filed with the patent office on 2013-04-04 for optical scanner apparatus and optical scanner control apparatus.
The applicant listed for this patent is Hisanori Aga, Riichiro Hibiya, Hisamichi Sekine, Somei Takahashi, Toyoki Tanaka. Invention is credited to Hisanori Aga, Riichiro Hibiya, Hisamichi Sekine, Somei Takahashi, Toyoki Tanaka.
Application Number | 20130083378 13/626059 |
Document ID | / |
Family ID | 47878804 |
Filed Date | 2013-04-04 |
United States Patent
Application |
20130083378 |
Kind Code |
A1 |
Tanaka; Toyoki ; et
al. |
April 4, 2013 |
OPTICAL SCANNER APPARATUS AND OPTICAL SCANNER CONTROL APPARATUS
Abstract
An optical scanner apparatus includes first and second torsion
beams which support a mirror support portion supporting a mirror
from both sides in an axial direction; first and second horizontal
driving beams configured to include first and second horizontal
driving sources, respectively, a connecting beam; a first
piezo-electric sensor; first and second sensor interconnects
connected to one of and the other of an upper electrode and a lower
electrode of the first piezo-electric sensor, respectively, the
first sensor interconnect and the second sensor interconnect being
formed to extend toward the first horizontal driving beam and the
second horizontal driving beam, respectively.
Inventors: |
Tanaka; Toyoki; (Tokyo,
JP) ; Takahashi; Somei; (Tokyo, JP) ; Sekine;
Hisamichi; (Tokyo, JP) ; Aga; Hisanori;
(Tokyo, JP) ; Hibiya; Riichiro; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tanaka; Toyoki
Takahashi; Somei
Sekine; Hisamichi
Aga; Hisanori
Hibiya; Riichiro |
Tokyo
Tokyo
Tokyo
Tokyo
Tokyo |
|
JP
JP
JP
JP
JP |
|
|
Family ID: |
47878804 |
Appl. No.: |
13/626059 |
Filed: |
September 25, 2012 |
Current U.S.
Class: |
359/199.4 |
Current CPC
Class: |
G02B 26/101 20130101;
G02B 26/0858 20130101; G01C 9/06 20130101; G01C 2009/066 20130101;
G01S 7/4817 20130101; G02B 26/105 20130101; G01B 11/25
20130101 |
Class at
Publication: |
359/199.4 |
International
Class: |
G02B 26/10 20060101
G02B026/10 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 3, 2011 |
JP |
2011-219255 |
Jul 6, 2012 |
JP |
2012-152834 |
Claims
1. An optical scanner apparatus comprising: a mirror; a mirror
support portion which supports the mirror; a first torsion beam and
a second torsion beam which support the mirror support portion from
both sides in an axial direction around which the mirror support
portion is oscillated by torsions of the first torsion beam and the
second torsion beam; a first horizontal driving beam and a second
horizontal driving beam provided to interpose the mirror and the
mirror support portion therebetween and configured to include a
first horizontal driving source and a second horizontal driving
source, respectively, for oscillating the mirror and the mirror
support portion around the axial direction; a connecting beam that
connects one side of the first horizontal driving beam and the
second horizontal driving beam to the first torsion beam; a first
piezo-electric sensor including a lower electrode, a piezo-electric
element and an upper electrode formed in this order on the
connecting beam and configured to detect a displacement of the
connecting beam by an oscillation of the first torsion beam and the
second torsion beam around the axial direction when the mirror is
being oscillated by driving voltages applied to the first
horizontal driving source and the second horizontal driving source
of the first horizontal driving beam and the second horizontal
driving beam, respectively; a first sensor interconnect and a
second sensor interconnect connected to one of the upper electrode
and the lower electrode of the first piezo-electric sensor and the
other of the upper electrode and the lower electrode of the first
piezo-electric sensor, respectively, the first sensor interconnect
and the second sensor interconnect being formed to extend toward
the first horizontal driving beam and the second horizontal driving
beam, respectively.
2. The optical scanner apparatus according to claim 1, further
comprising: a first drive interconnect for providing the driving
voltage to the first horizontal driving source formed to extend
along the first sensor interconnect; and a second drive
interconnect for providing the driving voltage to the second
horizontal driving source to extend along the second sensor
interconnect, and wherein a distance at which the first drive
interconnect and the first sensor interconnect extend along with
each other and a distance at which the second drive interconnect
and the second sensor interconnect extend along with each other are
substantially the same.
3. The optical scanner apparatus according to claim 1, further
comprising: a first drive interconnect for providing the driving
voltage to the first horizontal driving source formed to extend
along the first sensor interconnect; a second drive interconnect
for providing the driving voltage to the second horizontal driving
source to extend along the second sensor interconnect; a first
guard pattern connected to a ground terminal and provided between
the first drive interconnect and the first sensor interconnect; and
a second guard pattern connected to a ground terminal and provided
between the second drive interconnect and the second sensor
interconnect.
4. The optical scanner apparatus according to claim 3, wherein the
first guard pattern is formed at an entire portion between the
first drive interconnect and the first sensor interconnect, and the
second guard pattern is formed at an entire portion between the
second drive interconnect and the second sensor interconnect.
5. The optical scanner apparatus according to claim 1, further
comprising: a movable frame which surrounds the mirror, the mirror
support portion, the first torsion beam, the second torsion beam,
the first horizontal driving beam, the second horizontal driving
beam, and the connecting beam, a first vertical driving beam and a
second vertical driving beam provided to interpose the movable
frame therebetween, respectively connected to the movable frame and
configured to include a first vertical driving source and a second
vertical driving source, respectively, for oscillating the mirror
and the mirror support portion in a direction perpendicular to the
axial direction; and a second piezo-electric sensor including a
lower electrode, a piezo-electric element and an upper electrode
formed in this order on the first vertical driving beam, and
configured to detect a displacement of the first vertical driving
beam when the mirror is being oscillated by a driving voltage
applied to the first vertical driving source of the first vertical
driving beam.
6. The optical scanner apparatus according to claim 5, further
comprising: a third sensor interconnect and a fourth sensor
interconnect connected to one of the upper electrode and the lower
electrode of the second piezo-electric sensor and the other of the
upper electrode and the lower electrode of the second
piezo-electric sensor, respectively such that the third sensor
interconnect and the fourth sensor interconnect are formed to
extend along the first sensor interconnect, a first drive
interconnect for providing the driving voltage to the first
horizontal driving source formed to extend along the first sensor
interconnect; a second drive interconnect for providing the driving
voltage to the second horizontal driving source to extend along the
second sensor interconnect; a third drive interconnect or 210B
(203) for providing the driving voltage to the first vertical
driving source formed to extend along the first sensor
interconnect; a first guard pattern connected to a ground terminal
and provided to separate the first sensor interconnect, the third
sensor interconnect and the fourth sensor interconnect from the
first drive interconnect and the third drive interconnect; and a
second guard pattern connected to a ground terminal and provided
between the second drive interconnect and the second sensor
interconnect.
7. The optical scanner apparatus according to claim 6, further
comprising: a third piezo-electric sensor including a lower
electrode, a piezo-electric element and an upper electrode formed
in this order on the second vertical driving beam, and configured
to detect a displacement of the second vertical driving beam when
the mirror is being oscillated by a driving voltage applied to the
second vertical driving source of the second vertical driving beam;
a fifth sensor interconnect and a sixth sensor interconnect
connected to one of the upper electrode and the lower electrode of
the third piezo-electric sensor and the other of the upper
electrode and the lower electrode of the third piezo-electric
sensor, respectively such that the fifth sensor interconnect and
the sixth sensor interconnect are formed to extend along the second
sensor interconnect; and a fourth drive interconnect for providing
the driving voltage to the second vertical driving source formed to
extend along the second sensor interconnect, wherein the first
guard pattern and the second guard pattern are formed to extend
from points where the first sensor interconnect and the third
sensor interconnect and the fourth sensor interconnect start to
extend along with each other, and where the second sensor
interconnect and the fifth sensor interconnect and the sixth sensor
interconnect start to extend along with each other,
respectively.
8. The optical scanner apparatus according to claim 1, wherein the
first horizontal driving source and the second horizontal driving
source are driven by driving voltages whose phases are opposite
from each other.
9. An optical scanner control apparatus comprising: the optical
scanner apparatus according to claim 1; and a noise reduction unit
that generates a first noise equality component signal and a second
noise equality component signal from a first driving voltage
applied to the first horizontal driving source and a second driving
voltage applied to the second horizontal driving source,
respectively, and removes a noise component from an output of the
piezo-electric sensor based on the first noise equality component
signal and the second noise equality component signal.
10. The optical scanner control apparatus according to claim 9,
wherein the noise reduction unit includes a first gain-phase
adjustment unit and a second gain-phase adjustment unit
corresponding to the first driving voltage and the second driving
voltage, respectively, and the first noise equality component
signal is generated by adjusting the amplitude and the phase of the
first driving voltage by the first gain-phase adjustment unit, and
the second noise equality component signal is generated by
adjusting the amplitude and the phase of the second driving voltage
by the second gain-phase adjustment unit.
11. The optical scanner control apparatus according to claim 10,
wherein the amplitude and the phase of the first noise equality
component signal is adjusted to be equal to the amplitude and the
phase of a signal output from the first piezo-electric sensor when
the first driving voltage is applied to the first horizontal
driving source, the second driving voltage having a frequency by
which the mirror is not oscillated when the second driving voltage
is applied to the first horizontal driving source, and the
amplitude and the phase of the second noise equality component
signal is adjusted to be equal to the amplitude and the phase of a
signal output from the first piezo-electric sensor when the second
driving voltage is applied to the first horizontal driving source,
the second driving voltage having a frequency by which the mirror
is not oscillated when the second driving voltage is applied to the
first horizontal driving source.
12. The optical scanner control apparatus according to claim 9,
wherein the noise reduction unit includes an adding circuit that
adds the first noise equality component signal and the second noise
equality component signal, and a subtracting circuit that subtracts
an adding result of the first noise equality component signal and
the second noise equality component signal from the output of the
piezo-electric sensor.
13. The optical scanner control apparatus according to claim 10,
wherein the noise reduction unit includes a control unit that
generates the first noise equality component signal and the second
noise equality component signal by controlling the first gain-phase
adjustment unit and the second gain-phase adjustment unit from the
first driving voltage and the second driving voltage,
respectively.
14. An optical scanner apparatus comprising: a mirror; a mirror
support portion which supports the mirror; a first torsion beam and
a second torsion beam which support the mirror support portion from
both sides in an axial direction around which the mirror support
portion is oscillated by torsions of the first torsion beam and the
second torsion beam; a first horizontal driving beam and a second
horizontal driving beam provided to interpose the mirror and the
mirror support portion therebetween and configured to include a
first horizontal driving source and a second horizontal driving
source, respectively, for oscillating the mirror and the mirror
support portion around the axial direction; a connecting beam that
connects one side of the first horizontal driving beam and the
second horizontal driving beam to the first torsion beam; a first
piezo-electric sensor and a fourth piezo-electric sensor each
including a lower electrode, a piezo-electric element and an upper
electrode formed in this order on the connecting beam and
configured to detect a displacement of the connecting beam by an
oscillation of the first torsion beam and the second torsion beam
around the axial direction when the mirror is being oscillated by
driving voltages applied to the first horizontal driving source and
the second horizontal driving source of the first horizontal
driving beam and the second horizontal driving beam, respectively;
a first sensor interconnect and a second sensor interconnect
connected to one of the upper electrode and the lower electrode of
the first piezo-electric sensor and the other of the upper
electrode and the lower electrode of the first piezo-electric
sensor, respectively; a seventh sensor interconnect and an eighth
sensor interconnect connected to one of the upper electrode and the
lower electrode of the fourth piezo-electric sensor and the other
of the upper electrode and the lower electrode of the fourth
piezo-electric sensor, respectively; a first drive interconnect for
providing the driving voltage to the first horizontal driving
source; and a second drive interconnect for providing the driving
voltage to the second horizontal driving source, the first sensor
interconnect, the second sensor interconnect, the seventh sensor
interconnect and the eight sensor interconnect being formed to
extend toward one of the first horizontal driving beam and the
second sensor interconnect and the first drive interconnect and the
second drive interconnect being formed to extend toward the other
of the first horizontal driving beam and the second sensor
interconnect.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an optical scanner
apparatus and an optical scanner control apparatus.
[0003] 2. Description of the Related Art
[0004] Conventionally, an optical scanner apparatus in which a
mirror portion which reflects an input light is rotated around a
rotational axis by an actuator including a lower electrode, a
piezo-electric element and an upper electrode formed in this order
to scan the reflected light is known. By this actuator, the mirror
portion is oscillated in vertical and horizontal directions with
respect to a reflection surface by applying driving voltages to the
upper electrode and the lower electrode.
[0005] Further, in this optical scanner apparatus, a piezo-electric
sensor for detection which detects a voltage generated in the
piezo-electric element of the actuator while the mirror portion is
being oscillated is further provided. An inclination of the mirror
portion is detected by an output of the piezo-electric sensor for
detection so that the operation of the actuator is controlled.
[0006] The voltage detected by the piezo-electric sensor for
detection may be interfered by a noise as the voltage detected by
the piezo-electric sensor for detection when the mirror portion is
being oscillated is very small. Thus, various techniques have been
developed to appropriately detect the voltage by the piezo-electric
sensor for detection.
[0007] For example, Patent Document 1 discloses a technique in
which an electrode of the actuator and an electrode of the
piezo-electric sensor for detection are formed to be apart from
each other. With this structure, it is described in Patent Document
1 that the grounded voltages for the actuator and the
piezo-electric sensor for detection can be separated and the
interference of the noise caused by the grounded voltage of the
actuator to the voltage detected by the piezo-electric sensor for
detection can be avoided.
[0008] However, according to the conventional technique, the
voltage detected by the piezo-electric sensor for detection is very
small and is easily interfered by a noise (crosstalk) from other
signal lines. Thus, there is a possibility that an inclination of a
mirror cannot be precisely detected because of the noise
(crosstalk).
PATENT DOCUMENT
[Patent Document 1] Japanese Laid-open Patent Publication No.
2009-169195
SUMMARY OF THE INVENTION
[0009] The present invention is made in light of the above
problems, and provides an optical scanner apparatus and an optical
scanner control apparatus capable of precisely detecting an
inclination of a mirror by reducing a noise to sensor
interconnects.
[0010] According to an embodiment, there is provided an optical
scanner apparatus including a mirror; a mirror support portion
which supports the mirror;
[0011] a first torsion beam and a second torsion beam which support
the mirror support portion from both sides in an axial direction
around which the mirror support portion is oscillated by torsions
of the first torsion beam and the second torsion beam; a first
horizontal driving beam and a second horizontal driving beam
provided to interpose the mirror and the mirror support portion
therebetween and configured to include a first horizontal driving
source and a second horizontal driving source, respectively, for
oscillating the mirror and the mirror support portion around the
axial direction; a connecting beam that connects one side of the
first horizontal driving beam and the second horizontal driving
beam to the first torsion beam; a first piezo-electric sensor
including a lower electrode, a piezo-electric element and an upper
electrode formed in this order on the connecting beam and
configured to detect a displacement of the connecting beam by an
oscillation of the first torsion beam and the second torsion beam
around the axial direction when the mirror is being oscillated by
driving voltages applied to the first horizontal driving source and
the second horizontal driving source of the first horizontal
driving beam and the second horizontal driving beam, respectively;
a first sensor interconnect and a second sensor interconnect
connected to one of the upper electrode and the lower electrode of
the first piezo-electric sensor and the other of the upper
electrode and the lower electrode of the first piezo-electric
sensor, respectively, the first sensor interconnect and the second
sensor interconnect being formed to extend toward the first
horizontal driving beam and the second horizontal driving beam,
respectively.
[0012] According to another embodiment, there is provided an
optical scanner control apparatus including the above optical
scanner apparatus and a noise reduction unit that generates a first
noise equality component signal and a second noise equality
component signal from a first driving voltage applied to the first
horizontal driving source and a second driving voltage applied to
the second horizontal driving source, respectively, and removes a
noise component from an output of the piezo-electric sensor based
on the first noise equality component signal and the second noise
equality component signal.
[0013] According to another embodiment, there is provided an
optical scanner apparatus including a mirror; a mirror support
portion which supports the mirror; a first torsion beam and a
second torsion beam which support the mirror support portion from
both sides in an axial direction around which the mirror support
portion is oscillated by torsions of the first torsion beam and the
second torsion beam; a first horizontal driving beam and a second
horizontal driving beam provided to interpose the mirror and the
mirror support portion therebetween and configured to include a
first horizontal driving source and a second horizontal driving
source, respectively, for oscillating the mirror and the mirror
support portion around the axial direction; a connecting beam that
connects one side of the first horizontal driving beam and the
second horizontal driving beam to the first torsion beam; a first
piezo-electric sensor and a fourth piezo-electric sensor each
including a lower electrode, a piezo-electric element and an upper
electrode formed in this order on the connecting beam and
configured to detect a displacement of the connecting beam by an
oscillation of the first torsion beam and the second torsion beam
around the axial direction when the mirror is being oscillated by
driving voltages applied to the first horizontal driving source and
the second horizontal driving source of the first horizontal
driving beam and the second horizontal driving beam, respectively;
a first sensor interconnect and a second sensor interconnect
connected to one of the upper electrode and the lower electrode of
the first piezo-electric sensor and the other of the upper
electrode and the lower electrode of the first piezo-electric
sensor, respectively; a seventh sensor interconnect and an eighth
sensor interconnect connected to one of the upper electrode and the
lower electrode of the fourth piezo-electric sensor and the other
of the upper electrode and the lower electrode of the fourth
piezo-electric sensor, respectively; a first drive interconnect for
providing the driving voltage to the first horizontal driving
source; and a second drive interconnect for providing the driving
voltage to the second horizontal driving source, the first sensor
interconnect, the second sensor interconnect, the seventh sensor
interconnect and the eight sensor interconnect being formed to
extend toward one of the first horizontal driving beam and the
second sensor interconnect and the first drive interconnect and the
second drive interconnect being formed to extend toward the other
of the first horizontal driving beam and the second sensor
interconnect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Other objects, features and advantages of the present
invention will become more apparent from the following detailed
description when read in conjunction with the accompanying
drawings.
[0015] FIG. 1 is a view showing an example of an optical scanner
apparatus of an embodiment;
[0016] FIG. 2 is an enlarged view of a part "A" shown in FIG.
1;
[0017] FIG. 3 is an enlarged view of a part "B" shown in FIG.
1;
[0018] FIG. 4 is a view showing an example of an optical scanner
apparatus of an embodiment;
[0019] FIG. 5 is a view showing an example of guard patterns;
[0020] FIG. 6 is an enlarged view of a part "A1" shown in FIG.
4;
[0021] FIG. 7 is an enlarged view of a part "B1" shown in FIG.
4;
[0022] FIG. 8 is a view showing an example of an optical scanner
apparatus of an embodiment;
[0023] FIG. 9 is an enlarged view of a part "B2" shown in FIG.
8;
[0024] FIG. 10 is a block diagram showing an example of an optical
scanner apparatus of an embodiment;
[0025] FIG. 11 is a block diagram showing an example of gain-phase
adjustment units;
[0026] FIG. 12 is a circuit diagram showing an example of a circuit
structure of a noise reduction unit of an embodiment;
[0027] FIG. 13 is a flowchart showing an example of a process of
performing an adjustment for removing a noise component of an
embodiment;
[0028] FIG. 14 is a view showing a waveform output from a
piezo-electric sensor before removing the noise;
[0029] FIG. 15A and FIG. 15B are views showing an example of noise
equality components;
[0030] FIG. 16 is a view showing a waveform output from the
piezo-electric sensor after removing the noise;
[0031] FIG. 17 is a circuit diagram showing another example of a
circuit structure of a noise reduction unit of an embodiment;
[0032] FIG. 18 is a block diagram showing an optical scanner
apparatus of an embodiment;
[0033] FIG. 19 is a flowchart showing an example of a process of
performing an adjustment for removing a noise component of an
embodiment;
[0034] FIG. 20 is a view showing an example of an optical scanner
apparatus of an embodiment where a mirror portion is enlarged;
[0035] FIG. 21 is a view showing an example of waveforms output
from piezo-electric sensors of an embodiment;
[0036] FIG. 22 is a view showing an example of a waveform of a
difference signal of outputs of piezo-electric sensors of an
embodiment;
[0037] FIG. 23 is a block diagram showing an example of an optical
scanner apparatus of an embodiment;
[0038] FIG. 24 is a view showing an example of an optical scanner
module of an embodiment;
[0039] FIG. 25 is a side view of an optical scanner module of an
embodiment;
[0040] FIG. 26 is a view for explaining an example of a photo
sensor;
[0041] FIG. 27 is a view showing a position of a photo sensor;
[0042] FIG. 28 is a view for explaining measuring the inclination
of a mirror in the vertical direction;
[0043] FIG. 29 is a view showing an example of a comparison result
between an actual value and an output of a photo sensor;
[0044] FIG. 30 is a view showing an example of a comparison result
between an actual value and an output of a photo sensor; and
[0045] FIG. 31 is a view showing an example of a comparison result
between an actual value and an output of a photo sensor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] The invention will be described herein with reference to
illustrative embodiments. Those skilled in the art will recognize
that many alternative embodiments can be accomplished using the
teachings of the present invention and that the invention is not
limited to the embodiments illustrated for explanatory
purposes.
[0047] It is to be noted that, in the explanation of the drawings,
the same components are given the same reference numerals, and
explanations are not repeated.
First Embodiment
[0048] The first embodiment is explained with reference to
drawings. FIG. 1 is a view showing an example of an optical scanner
apparatus 100 of the first embodiment.
[0049] The optical scanner apparatus 100 of the embodiment includes
a mirror 110, a mirror support portion 120, a first torsion beam
130A, a second torsion beam 130B, a first connecting beam 140A, a
second connecting beam 140B, a first horizontal driving beam 150A,
a second horizontal driving beam 150B, a movable frame 160, a first
vertical driving beam 170A, a second vertical driving beam 170B,
and a fixed frame 180.
[0050] The first horizontal driving beam 150A and the second
horizontal driving beam 150B of the embodiment include a first
horizontal driving source 151A and a second horizontal driving
source 151B, respectively. The first vertical driving beam 170A and
the second vertical driving beam 170B include a first vertical
driving source 171A and a second vertical driving source 171B,
respectively.
[0051] The mirror support portion 120 of the embodiment is provided
with slits 122 along a circumference of the mirror 110. By forming
the slits 122, the mirror support portion 120 can be lightened so
that torsion by the first torsion beam 130A and the second torsion
beam 130B can be appropriately transmitted to the mirror 110.
[0052] In the optical scanner apparatus 100 of the embodiment, the
mirror 110 is supported at a surface of the mirror support portion
120. The mirror support portion 120 is connected to ends of the
first torsion beam 130A and the second torsion beam 130B which are
provided at both ends of the mirror support portion 120.
[0053] The first torsion beam 130A and the second torsion beam 130B
form an oscillating shaft of the mirror 110 and extend in an axial
direction (vertical direction in FIG. 1) of the oscillating shaft
while supporting the mirror support portion 120 at both ends of the
mirror support portion 120 in the axial direction. When the first
torsion beam 130A and the second torsion beam 130B are distorted,
the mirror 110 supported by the mirror support portion 120 is
oscillated so that reflected light irradiated on the mirror 110 is
scanned.
[0054] The first torsion beam 130A and the second torsion beam 130B
are connected to be supported by the first connecting beam 140A and
the second connecting beam 140B, respectively. The first torsion
beam 130A and the second torsion beam 130B are connected to the
first horizontal driving beam 150A via the first connecting beam
140A and to the second horizontal driving beam 150B via the second
connecting beam 140B, respectively.
[0055] The first horizontal driving beam 150A, the second
horizontal driving beam 150B, the first connecting beam 140A, the
second connecting beam 140B, the first torsion beam 130A, the
second torsion beam 130B, the mirror support portion 120 and the
mirror 110 are surrounded by the movable frame 160. One ends of the
first horizontal driving beam 150A and the second horizontal
driving beam 150B are supported by the movable frame 160. The other
end of the first horizontal driving beam 150A is connected to the
first connecting beam 140A and the second connecting beam 140B at
an inner side. Similarly, the other end of the second horizontal
driving beam 150B is connected to the first connecting beam 140A
and the second connecting beam 140B at inner side.
[0056] The first horizontal driving beam 150A and the second
horizontal driving beam 150B are placed to face with each other in
a direction (horizontal direction in FIG. 1) perpendicular to the
axial direction of the oscillating shaft formed by the first
torsion beam 130A and the second torsion beam 130B while
interposing the mirror 110 and the mirror support portion 120
therebetween.
[0057] The first horizontal driving source 151A and the second
horizontal driving source 151B are formed on surfaces of the first
horizontal driving beam 150A and the second horizontal driving beam
150B, respectively. Each of the first horizontal driving source
151A and the second horizontal driving source 151B include a lower
electrode, a thin film of piezo-electric element and an upper
electrode formed in this order on the first horizontal driving beam
150A and the second horizontal driving beam 150B, respectively.
[0058] The first horizontal driving source 151A and the second
horizontal driving source 151B extend or shrink in accordance with
polarities of driving voltages applied to the upper electrode and
the lower electrode. Thus, by alternately applying driving voltages
of different phases to the first horizontal driving beam 150A and
the second horizontal driving beam 150B, the first horizontal
driving beam 150A and the second horizontal driving beam 150B
alternately oscillate upward or downward, opposite from each other,
at right-side and left-side of the mirror 110. Therefore, the
mirror 110 is oscillated or rotated around the oscillating shaft
formed by the first torsion beam 130A and the second torsion beam
130B. The oscillating or rotating direction of the mirror 110
around the oscillating shaft formed by the first torsion beam 130A
and the second torsion beam 130B is referred to as a "horizontal
direction" hereinafter. For example, for driving the first
horizontal driving beam 150A and the second horizontal driving beam
150B in the horizontal direction, a resonance frequency may be used
to oscillate the mirror 110 at high speed.
[0059] One ends of the first vertical driving beam 170A and the
second vertical driving beam 170B are connected to outer side of
the movable frame 160, respectively. The first vertical driving
beam 170A and the second vertical driving beam 170B are provided to
face with each other in the direction perpendicular to the axial
direction of the oscillating shaft formed by the first torsion beam
130A and the second torsion beam 130B while interposing the movable
frame 160 therebetween.
[0060] The first vertical driving beam 170A includes plural beams
which are extending in parallel with respect to the first
horizontal driving beam 150A where adjacent beams are connected
with each other at respective ends to form a zig-zag shape as a
whole. The other end of the first vertical driving beam 170A is
connected to an inner side of the fixed frame 180.
[0061] Similarly, the second vertical driving beam 170B includes
plural beams which are extending in parallel with respect to the
second horizontal driving beam 150B where adjacent beams are
connected with each other at respective ends to form a zig-zag
shape as a whole. The other end of the second vertical driving beam
170B is connected to an inner side of the fixed frame 180
[0062] The first vertical driving source 171A and the second
vertical driving source 171B are formed on surfaces of each of the
rectangular beams, not including curbed portions, of the first
vertical driving beam 170A and the second vertical driving beam
170B, respectively. In this embodiment, the first vertical driving
source 171A includes driving sources 171AR, 171BR, 171CR and 171DR
aligned from the movable frame 160 to right side. The second
vertical driving source 171B includes driving sources 171DL, 171CL,
171BL and 171AL aligned from left side to the movable frame
160.
[0063] Each of the driving sources 171AR, 171BR, 171CR and 171DR of
the first vertical driving source 171A includes a lower electrode,
a thin film of piezo-electric element and an upper electrode formed
in this order on the respective rectangular beam of the first
vertical driving beam 170A. Similarly, each of the driving sources
171DL, 171CL, 171BL and 171AL of the second vertical driving source
171B includes a lower electrode, a thin film of piezo-electric
element and an upper electrode formed in this order on the
respective rectangular beam of the second vertical driving beam
170B.
[0064] In the first vertical driving beam 170A and the second
vertical driving beam 170B, by applying driving voltages of
different polarities to the adjacent driving sources of the
adjacent rectangular beams, the adjacent rectangular beams are
warped in the opposite directions in the upper and lower direction.
Thus, the accumulated movement of the rectangular beams in the
upper and lower direction is transmitted to the movable frame 160.
The first vertical driving beam 170A and the second vertical
driving beam 170B oscillate the mirror 110 in the vertical
direction, which is perpendicular to the horizontal direction by
this operation. For example, for driving the first vertical driving
beam 170A and the second vertical driving beam 170B in the vertical
direction, a non-resonance frequency may be used.
[0065] At this time, by driving the driving sources 171AR and 171AL
and the driving sources 171CR and 171CL (4 in total) by the same
waveform, and the driving sources 171BR and 171BL and the driving
sources 171DR and 171DL (4 in total) by the waveform with different
phase from that for the driving sources 171AR and 171AL and the
driving sources 171CR and 171CL, the mirror 110 can be oscillated
in the vertical direction.
[0066] The optical scanner apparatus 100 of the embodiment further
includes piezo-electric sensors 191, 192, 193 and 194 which detect
an inclination of the mirror 110 in the horizontal direction when
the mirror 110 is oscillated in the horizontal direction by
applying driving voltage to the first horizontal driving source
151A and the second horizontal driving source 151B. The
piezo-electric sensors 191 and 192 are provided at the connecting
beam 140B and the piezo-electric sensors 193 and 194 are provided
at the connecting beam 140A.
[0067] The optical scanner apparatus 100 of the embodiment further
includes piezo-electric sensors 195 and 196 which detect an
inclination of the mirror 110 in the vertical direction when the
mirror 110 is oscillated in the vertical direction by applying
driving voltage to the first vertical driving source 171A and the
second vertical driving source 171B. The piezo-electric sensor 195
is provided to one of the rectangular beams of the first vertical
driving beam 170A, and the piezo-electric sensor 196 is provided to
one of the rectangular beams of the second vertical driving beam
170B.
[0068] The piezo-electric sensors 191 and 192 of the embodiment
output current values corresponding to a displacement of the
connecting beam 130B which is transmitted from the torsion beam
130B in accordance with the inclination of the mirror 110 in the
horizontal direction, respectively. The piezo-electric sensors 193
and 194 of the embodiment output current values corresponding to a
displacement of the connecting beam 140A which is transmitted from
the torsion beam 130A in accordance with the inclination of the
mirror 110 in the horizontal direction, respectively.
[0069] The piezo-electric sensor 195 (an example of a second
piezo-electric sensor) of the embodiment outputs a current value
corresponding to a displacement of the respective rectangular beam
at which the piezo-electric sensor 195 is provided, among the
plural driving beams of the first vertical driving beam 170A in
accordance with the inclination of the mirror 110 in the vertical
direction. The piezo-electric sensor 196 (an example of a third
piezo-electric sensor) of the embodiment outputs a current value
corresponding to a displacement of the respective rectangular beam
at which the piezo-electric sensor 196 is provided, among the
plural driving beams of the second vertical driving beam 170B in
accordance with the inclination of the mirror 110 in the vertical
direction.
[0070] In this embodiment, the inclination of the mirror 110 in the
horizontal direction is detected using an output of one of the
piezo-electric sensors 191 to 194. Further in this embodiment, the
inclination of the mirror 110 in the vertical direction is detected
using an output of one of the piezo-electric sensors 195 and
196.
[0071] Further in this embodiment, an inclination detection unit
that detects an inclination of the mirror 110 based on the current
value output from each of the piezo-electric sensors may be
provided outside the optical scanner apparatus 100. Further in this
embodiment, a drive control unit that controls driving voltages to
be supplied to the first horizontal driving source 151A, the second
horizontal driving source 151B, the first vertical driving source
171A and the second vertical driving source 171B, based on a
detected result by the inclination detection unit may be provided
outside the optical scanner apparatus 100.
[0072] Each of the piezo-electric sensors 191 to 196 includes a
lower electrode, a thin film of piezo-electric element and an upper
electrode formed in this order. In this embodiment, outputs from
the piezo-electric sensors 191 to 196 are current values of sensor
interconnects which are connected to the upper electrodes and the
lower electrodes, respectively.
[0073] In FIG. 1, an example where the piezo-electric sensor 191
(an example of a piezo-electric sensor) is used for detecting the
inclination of the mirror 110 in the horizontal direction is shown.
With reference to FIG. 2, the piezo-electric sensor 191 is
explained. FIG. 2 is an enlarged view of a part "A" shown in FIG.
1.
[0074] The piezo-electric sensor 191 is placed at a connecting
portion 131 between the connecting beam 140B and the torsion beam
130B in the connecting beam 140B and at a driving source 151B side.
The piezo-electric sensor 192 is also placed at the connecting
portion 131 and at a driving source 151A side. The piezo-electric
sensor 193 is placed at a connecting portion 132 between the
connecting beam 140A and the torsion beam 130A in the connecting
beam 140A and at a driving source 151B side. The piezo-electric
sensor 194 is placed at the connecting portion 132 and at a driving
source 151A side.
[0075] Each of the piezo-electric sensors 191 and 192 includes a
lower electrode, a thin film of piezo-electric element, and an
upper electrode formed in this order on the connecting beam 140B,
respectively. Each of the piezo-electric sensors 193 and 194
includes a lower electrode, a thin film of piezo-electric element,
and an upper electrode formed in this order on the connecting beam
140A, respectively.
[0076] Further in this embodiment, only an output from the
piezo-electric sensor 191 is used. Thus, a first sensor
interconnect 201 and a second sensor interconnect 202 are only
connected to the piezo-electric sensor 191. In this example, the
piezo-electric sensors 192 to 194 are dummy sensors for balancing
the weights of the first connecting beam 140A and the second
connecting beam 140B.
[0077] The first sensor interconnect 201 is a lower electrode
interconnect which is connected to the lower electrode of the
piezo-electric sensor 191. The second sensor interconnect 202 is an
upper electrode interconnect which is connected to the upper
electrode of the piezo-electric sensor 191.
[0078] The first sensor interconnect 201 is extended toward a first
horizontal driving beam 150A side from the piezo-electric sensor
191, while the second sensor interconnect 202 is extended toward a
second horizontal driving beam 150B side from the piezo-electric
sensor 191. In other words, in this embodiment, the first sensor
interconnect 201 and the second sensor interconnect 202 are
extended toward right and left directions of the piezo-electric
sensor 191 such that the first sensor interconnect 201 and the
second sensor interconnect 202 are extended toward opposite
directions from the piezo-electric sensor 191.
[0079] The first sensor interconnect 201 of the embodiment is led
along a first drive interconnect for lower 203 for applying the
driving voltage to the lower electrode of the first horizontal
driving source 151A and a first drive interconnect for upper 204
(an example of a first drive interconnect) for applying the driving
voltage to the upper electrode of the first horizontal driving
source 151A, and is connected to a terminal included in group of
terminals TA provided at a right side of the fixed frame 180.
[0080] The second sensor interconnect 202 of the embodiment is led
along a second drive interconnect for lower 205 for applying the
driving voltage to the lower electrode of the second horizontal
driving source 151B and a second drive interconnect for upper 206
(an example of a second drive interconnect) for applying the
driving voltage to the upper electrode of the second horizontal
driving source 151B, and is connected to a terminal included in
group of terminals TB provided at a left side of the fixed frame
180.
[0081] In this embodiment, the terminal connected to the first
sensor interconnect 201 in the group of terminals TA, and the
terminal connected to the second sensor interconnect 202 in the
group of terminals TB may be connected to the inclination detection
unit that detects the inclination of the mirror 10 in the
horizontal direction. Further in this embodiment, the terminals
respectively connected to the first drive interconnect for lower
203 and the first drive interconnect for upper 204 in the group of
terminals TA, and the terminals respectively connected to the
second drive interconnect for lower 205 and the second drive
interconnect for upper 206 in the group of terminals TB may be
connected to the drive control unit.
[0082] Further in this embodiment, the length of a part of the
first sensor interconnect 201 which extends along the first drive
interconnect for lower 203 and the first drive interconnect for
upper 204 and the length of a part of the second sensor
interconnect 202 which extends along the second drive interconnect
for lower 205 and the second drive interconnect for upper 206 are
configured to be the same.
[0083] In this embodiment, by structuring the first sensor
interconnect 201 and the second sensor interconnect 202 as
described above, the noises caused by the first horizontal driving
source 151A and the second horizontal driving source 151B which are
driven by the driving signals (voltages) whose phases are opposite
from each other are canceled from each other so that the output of
the piezo-electric sensor 191 can be precisely detected. Thus, in
this embodiment, the inclination of the mirror 110 in the
horizontal direction detected by the output of the piezo-electric
sensor 191 can be precisely detected.
[0084] With reference to FIG. 3, the piezo-electric sensor 195 is
explained. FIG. 3 is an enlarged view of a part "B" shown in FIG.
1.
[0085] The piezo-electric sensor 195 is provided at an upper end
portion of one of the rectangular beams of the first vertical
driving beam 170A. The piezo-electric sensor 195 includes a lower
electrode, a thin film of piezo-electric element, and an upper
electrode formed in this order on a surface of the respective
rectangular beam of the first vertical driving beam 170A.
[0086] The output of the piezo-electric sensor 195 is output from a
third sensor interconnect 207A and a fourth sensor interconnect
208A. The third sensor interconnect 207A is a lower electrode
interconnect which is connected to the lower electrode of the
piezo-electric sensor 195. The fourth sensor interconnect 208A is
an upper electrode interconnect which is connected to the upper
electrode of the piezo-electric sensor 195. The third sensor
interconnect 207A and the fourth sensor interconnect 208A are
connected to terminals included in the group of terminals TA,
respectively.
[0087] The third sensor interconnect 207A and the fourth sensor
interconnect 208A of the embodiment are led along the first drive
interconnect for lower 203 for applying the driving voltage to the
lower electrode of the first vertical driving source 171A (and the
lower electrode of the first horizontal driving source 151A) and a
third drive interconnect for upper 210A for applying the driving
voltage to the upper electrode of the first vertical driving source
171A. As a common driving voltage is applied to the lower electrode
of the first horizontal driving source 151A and the lower electrode
of the first vertical driving source 171A, the first drive
interconnect for lower 203 is commonly used for the lower electrode
of the first horizontal driving source 151A and the first vertical
driving source 171A.
[0088] Although the third sensor interconnect 207A and the fourth
sensor interconnect 208A extend along the first drive interconnect
for lower 203 and the third drive interconnect for upper 210A, the
first sensor interconnect 201 is formed to extend between the third
sensor interconnect 207A and the fourth sensor interconnect 208A,
and the first drive interconnect for lower 203 and the third drive
interconnect for upper 210A. Thus, the distance between the third
sensor interconnect 207A and the fourth sensor interconnect 208A,
and the first drive interconnect for lower 203 and the third drive
interconnect for upper 210A can be widened to a certain degree.
[0089] In this embodiment, by structuring the third sensor
interconnect 207A and the fourth sensor interconnect 208A as
described above, the inclination of the mirror 110 in the vertical
direction detected by the output of the piezo-electric sensor 195
can be precisely detected.
[0090] Only the piezo-electric sensor 195 is explained with
reference to FIG. 3, the piezo-electric sensor 196 has a similar
structure as that of the piezo-electric sensor 195. The
piezo-electric sensor 196 is provided at an upper end portion of
one of the rectangular beams of the second vertical driving beam
170B.
[0091] In this embodiment, according to the above structure,
crosstalk from the drive interconnects can be reduced so that the
inclination of the mirror 110 can be precisely detected.
Second Embodiment
[0092] The second embodiment is explained with reference to
drawings. The second embodiment is different from the first
embodiment that a guard pattern is provided between the sensor
interconnect and the drive interconnect. In the following
explanation, the same components are given the same reference
numerals, and explanations are not repeated.
[0093] FIG. 4 is a view showing an example of an optical scanner
apparatus 100A of the second embodiment. The optical scanner
apparatus 100A includes a guard pattern 220 formed between the
sensor interconnects (the first sensor interconnect 201) and the
drive interconnects (first drive interconnect for lower 203).
Further, the optical scanner apparatus 100A includes a guard
pattern 221 formed between the second sensor interconnect 202 and
the second drive interconnect for lower 205.
[0094] With reference to FIG. 5, the guard patterns 220 and 221 of
the embodiment are explained. FIG. 5 is a view showing an example
of the guard patterns 220 and 221. In FIG. 5, interconnects which
are connected to the group of terminals TA or the group of
terminals TB are shown, for example.
[0095] The first sensor interconnect 201 connected to the lower
electrode of the piezo-electric sensor 191, the third sensor
interconnect 207A connected to the lower electrode of the
piezo-electric sensor 195, the fourth sensor interconnect 208A
connected to the upper electrode of the piezo-electric sensor 195
are connected to the group of terminals TA. Further, the first
drive interconnect for lower 203 connected to the lower electrode
of the first horizontal driving source 151A and the lower electrode
of the first vertical driving source 171A, the first drive
interconnect for upper 204 connected to the upper electrode of the
first horizontal driving source 151A, and the fifth drive
interconnects 210A connected to the upper electrodes of the first
vertical driving source 171A are connected to the group of
terminals TA. The guard pattern 220 is also connected to the group
of terminals TA.
[0096] The second sensor interconnect 202 connected to the upper
electrode of the piezo-electric sensor 191, a fifth sensor
interconnect 207B connected to the lower electrode of the
piezo-electric sensor 196, and a sixth sensor interconnect 208B
connected to the upper electrode of the piezo-electric sensor 196
are connected to the group of terminals TB. Further, the second
drive interconnect for lower 205 connected to the lower electrode
of the second horizontal driving source 151B and the lower
electrode of the second vertical driving source 171B, the second
drive interconnect for upper 206 connected to the upper electrode
of the second horizontal driving source 151B, and a fourth drive
interconnect for upper 210B connected to the upper electrode of the
second vertical driving source 171B are connected to the group of
terminals TB. The guard pattern 221 is also connected to the group
of terminals TB.
[0097] The guard patterns 220 and 221 of the embodiment are
connected to ground terminals in the group of terminals TA and in
the group of terminals TB, respectively.
[0098] With reference to FIG. 6 and FIG. 7, positions where the
guard patterns 220 and 221 of the embodiment are formed are
explained.
[0099] FIG. 6 is an enlarged view of a part "A1" shown in FIG.
4.
[0100] The guard pattern 220 of the embodiment is formed from a
position P1 where the first sensor interconnect 201 reaches the
first vertical driving beam 170A via the first horizontal driving
beam 150A. At the position Pl, the first sensor interconnect 201 is
started to extend along the first drive interconnect for lower 203.
Thus, the guard pattern 220 is formed between the first sensor
interconnect 201 and the first drive interconnect for lower 203
where these interconnects extend along with each other.
[0101] The guard pattern 221 of the embodiment is formed from a
position P2 where the second sensor interconnect 202 reaches the
second vertical driving beam 170B via the second horizontal driving
beam 150B. At the position P2, the second sensor interconnect 202
is started to extend along the third drive interconnect 203. Thus,
the guard pattern 221 is formed between the second sensor
interconnect 202 and the second drive interconnect for lower 205
where these interconnects extend along with each other.
[0102] Further, in this embodiment, a first dummy sensor
interconnect 201A and a second dummy sensor interconnect 202A,
which have corresponding structures as the first sensor
interconnect 201 and the second sensor interconnect 202, are formed
at a connecting beam 140A side. Further, in this embodiment, dummy
guard patterns 222 and 223 are formed at a first dummy sensor
interconnect 201A side and a second dummy sensor interconnect 202A
side as dummies of the guard patterns 220 and 221,
respectively.
[0103] In this embodiment, by forming the first dummy sensor
interconnect 201A, the second dummy sensor interconnect 202A and
the dummy guard patterns 222 and 223, the weights of the first
horizontal driving beam 150A and the second horizontal driving beam
150B are balanced so that the driving forces can be precisely
transmitted to the mirror 110.
[0104] FIG. 7 is an enlarged view of a part "B1" shown in FIG. 4.
The guard pattern 220 of the embodiment is formed along the first
sensor interconnect 201 which is formed from the position P1 (see
FIG. 6) toward the group of terminals TA. Further, the third drive
interconnect for upper 210A connected to the upper electrode of the
first vertical driving source 171A extends from the vicinity of the
piezo-electric sensor 195 toward the group of terminals TA.
Further, the third sensor interconnect 207A and the fourth sensor
interconnect 208A are also extend from the piezo-electric sensor
195 toward the group of terminals TA. Thus, the guard pattern 220
of the embodiment is formed to extend between the sensor
interconnects (the first sensor interconnect 201, the third sensor
interconnect 207A and the fourth sensor interconnect 208A) and the
drive interconnects (the third drive interconnect for upper 210A
and the first drive interconnects 203). Specifically, the guard
pattern 220 is formed to extend between the first sensor
interconnect 201 and the third drive interconnect for upper 210A
from the vicinity of the piezo-electric sensor 195.
[0105] Only the piezo-electric sensor 195 side is explained with
reference to FIG. 7, the guard pattern 221 is similarly formed at
the piezo-electric sensor 196 side.
[0106] In this embodiment, as described above, by forming the guard
patterns 220 and 221, influences from the drive interconnects to
the sensor interconnects can be suppressed so that the inclination
of the mirror 110 can be precisely detected.
Third Embodiment
[0107] The third embodiment is explained with reference to
drawings. The third embodiment is different from the second
embodiment that the guard pattern is only provided from the
vicinities of the piezo-electric sensors 195 and 196, respectively.
In the following explanation, the same components are given the
same reference numerals, and explanations are not repeated. FIG. 8
is a view showing an example of an optical scanner apparatus 100B
of the third embodiment. The optical scanner apparatus 100B
includes a guard pattern 220A and a guard pattern 221A at the
piezo-electric sensor 195 side and the piezo-electric sensor 196
side, respectively.
[0108] FIG. 9 is an enlarged view of a part B2 shown in FIG. 8.
[0109] In this embodiment, the guard pattern 220A which extends
along the first sensor interconnect 201 connected to the
piezo-electric sensor 191 is formed from a position P3 which is in
the vicinity of the piezo-electric sensor 195. The position P3 is
almost the same as a starting point of the third sensor
interconnect 207A and the fourth sensor interconnect 208A to be
extended along the first sensor interconnect 201, for example.
[0110] Although only the guard pattern 220A formed from the
vicinity of the piezo-electric sensor 195 is explained with
reference to FIG. 9, the guard pattern 221A is similarly formed
from the vicinity of the piezo-electric sensor 196 at the
piezo-electric sensor 196 side.
[0111] In this embodiment, with the above structure, noise can be
reduced so that the inclination of the mirror 110 can be precisely
detected.
Fourth Embodiment
[0112] The fourth embodiment is explained with reference to
drawings. In the fourth embodiment, the inclination of the mirror
10 can be more precisely detected by generating a noise equality
component which is equal to a noise component generated by the
driving signals from the driving signal and subtracting the
generated noise equality component from the output of the
piezo-electric sensor. Here, the noise component is slightly
generated by the length of the drive interconnects or a space
between the interconnects caused by the driving signals. In the
following explanation, the same components are given the same
reference numerals, and explanations are not repeated.
[0113] FIG. 10 is a block diagram showing an example of an optical
scanner control apparatus 300 of the fourth embodiment. The optical
scanner control apparatus 300 of the embodiment includes a front
end Integrated Circuit (IC) 400, a Laser Diode (LD) 440, and a
mirror driver IC 500 in addition to the optical scanner apparatus
100 of the first embodiment.
[0114] The front end IC 400 of the embodiment performs signal
process on an input video signal and provides it to the LD 440. The
front end IC 400 of the embodiment provides a signal for
controlling oscillation of the mirror 110 to the optical scanner
apparatus 100.
[0115] The front end IC 400 of the embodiment includes a video
signal processing unit 410, an LD driver 420, and a mirror control
unit 430. The video signal processing unit 410 divides the video
signal into a synchronizing signal, a luminance signal and a
chromaticity signal. The video signal processing unit 410 provides
the luminance signal and the chromaticity signal to the LD driver
420 and provides the synchronizing signal to the mirror control
unit 430.
[0116] The LD driver 420 controls the LD 440 based on the signal
provided from the video signal processing unit 410.
[0117] The mirror control unit 430 controls to oscillate the mirror
110 based on the output signal of the piezo-electric sensor 191
output from the mirror driver IC 500 and the synchronizing signal.
Specifically, the mirror control unit 430 outputs driving voltages
(referred to as "driving signals" hereinafter) of the first
horizontal driving source 151A, the second horizontal driving
source 151BB, the first vertical driving source 171A, and the
second vertical driving source 171B of the optical scanner
apparatus 100 via the mirror driver IC 500.
[0118] The mirror driver IC 500 of the embodiment includes a phase
inverter units 510 and 511, a buffer 570, and a noise reduction
unit 600.
[0119] The phase inverter units 510 and 511 invert the phases of
the driving signals output from the mirror control unit 430,
respectively. Specifically, the phase inverter unit 510 inverts the
phase of the driving signal to be provided to the first horizontal
driving source 151A to form a driving signal for the second
horizontal driving source 151B. The phase inverter unit 511 inverts
the phase of the driving signal to be provided to the first
vertical driving source 171A to form a driving signal for the
second vertical driving source 171B.
[0120] The noise reduction unit 600 of the embodiment reduces a
noise component which is superposed on the output of the
piezo-electric sensor 191. The noise component is a crosstalk
component of which a slight amount is generated by the length of
the drive interconnects or a space between the interconnects caused
by the driving signals provided to the first horizontal driving
source 151A, the second horizontal driving source 151B, the first
vertical driving source 171A, and the second vertical driving
source 171B.
[0121] The noise reduction unit 600 shown in FIG. 10 reduces the
noise component caused by the driving signals provided to the first
horizontal driving source 151A and the second horizontal driving
source 151B. Although not shown in the drawings, the optical
scanner control apparatus 300 of the embodiment further includes a
noise reduction unit which reduces a noise component caused by the
driving signals provided to the first vertical driving source 171A
and the second vertical driving source 171B. The noise reduction
unit corresponding to the first vertical driving source 171A and
the second vertical driving source 171B has a similar structure as
the noise reduction unit 600 shown in FIG. 10.
[0122] The noise reduction unit 600 of the embodiment includes
gain-phase adjustment units 520 and 530, an adding circuit 540, a
buffer 550, and a subtracting circuit 560.
[0123] The gain-phase adjustment units 520 and 530 generate
components equal to the noise components superposed on the output
of the piezo-electric sensor 191 from the driving signals provided
to the first horizontal driving source 151A and the second
horizontal driving source 151B, respectively. In the following
explanation, the driving signal provided to the first horizontal
driving source 151A is referred to as a first driving signal, and
the driving signal provided to the second horizontal driving source
151B is referred to as a second driving signal.
[0124] The gain-phase adjustment unit 520 of the embodiment
generates a component equal to the noise component superposed on
the output of the piezo-electric sensor 191 when the first driving
signal is applied to the first horizontal driving source 151A. The
gain-phase adjustment unit 530 of the embodiment generates a
component equal to the noise component superposed on the output of
the piezo-electric sensor 191 when the second driving signal is
applied to the second horizontal driving source 151B. The
gain-phase adjustment units 520 and 530 are explained later in
detail.
[0125] The adding circuit 540 adds the outputs from the gain-phase
adjustment units 520 and 530. In this embodiment, by adding the
outputs from the gain-phase adjustment units 520 and 530, a
component equal to the noise component superposed on the output of
the piezo-electric sensor 191 when the first driving signal and the
second driving signal are provided to the first horizontal driving
source 151A and the second horizontal driving source 151B,
respectively, at the same time is generated.
[0126] The buffer 550 amplifies the output of the piezo-electric
sensor 191. In this embodiment, it is assumed that only the
piezo-electric sensor 191 is provided to the optical scanner
apparatus 100 for detecting the inclination of the mirror 110 in
the horizontal direction. The piezo-electric sensor 191 outputs a
current value corresponding to the displacement of the connecting
beam 140B transmitted from the torsion beam 130B in accordance with
the inclination of the mirror 110 in the horizontal direction. When
the output of the piezo-electric sensor 192 is also used in
addition to the output of the piezo-electric sensor 191, the buffer
570 is used. However, in this embodiment, as described above, it is
assumed that only the piezo-electric sensor 191 is used. Thus, in
such a case, the optical scanner control apparatus 300 of the
embodiment may not include the buffer 570.
[0127] The subtracting circuit 560 subtracts the output of the
adding circuit 540 from the output of the buffer 550. The output of
the buffer 550 of the embodiment is a signal in which a noise is
superposed on the actual output of the piezo-electric sensor 191.
Further, the output of the adding circuit 540 is equal to the noise
component superposed on the output of the piezo-electric sensor
191. Thus, by subtracting the output of the adding circuit 540 from
the output of the buffer 550, the noise component can be removed
from the output of the piezo-electric sensor 191. The output of the
subtracting circuit 560 is provided to the mirror control unit 430
of the front end IC 400.
[0128] The gain-phase adjustment units 520 and 530 are explained.
FIG. 11 is a block diagram showing an example of the gain-phase
adjustment units 520 and 530.
[0129] The gain-phase adjustment unit 520 of the embodiment
includes an AC coupling circuit 521, an attenuator circuit 522, and
a phase correction circuit 523. Similarly, the gain-phase
adjustment unit 530 of the embodiment includes an AC coupling
circuit 531, an attenuator circuit 532 and a phase correction
circuit 533. In this embodiment, the gain-phase adjustment unit 520
corresponds to the first driving signal, and the gain-phase
adjustment unit 530 corresponds to the second driving signal. The
structures of the gain-phase adjustment unit 520 and the gain-phase
adjustment unit 530 are the same. Thus, in the following
explanation, the structure of the gain-phase adjustment unit 520 is
explained and the explanation of the gain-phase adjustment unit 530
is not repeated.
[0130] The AC coupling circuit 521 of the embodiment takes ground
voltage as a reference voltage of the first driving signal. The
attenuator circuit 522 changes the amplitude of the first driving
signal to be equal to the amplitude of the noise component output
from the piezo-electric sensor 191. The phase correction circuit
523 corrects the phase of the component generated from the first
driving signal to meet the phase of the noise component.
[0131] With reference to FIG. 12, a circuit structure of the noise
reduction unit 600 of the embodiment is explained. FIG. 12 is a
circuit diagram showing an example of a circuit structure of the
noise reduction unit 600 of the fourth embodiment.
[0132] The noise reduction unit 600 of the embodiment includes
amplifiers AP21 to AP28, variable resistors R11 to R14, resistors
R21 to R37, and capacitors C21 to C24.
[0133] The AC coupling circuit 521 of the embodiment is composed of
the capacitor C21 and the AC coupling circuit 531 is composed of
the capacitor C22. The first driving signal is input to one end of
the capacitor C21, and the second driving signal is input to one
end of the capacitor C22.
[0134] The other end of the capacitor C21 is connected to one end
of the variable resistor R11, which is an input of the attenuator
circuit 522. The other end of the capacitor C31 is connected to one
end of the variable resistor R12, which is an input of the
attenuator circuit 532.
[0135] The attenuator circuit 522 includes the variable resistor
R11, the resistor R21, and the amplifier AP21. The attenuator
circuit 532 includes the variable resistor R12, the resistor R22,
and the amplifier AP22.
[0136] In the attenuator circuit 522, one end of the variable
resistor R11 is connected to the other end of the capacitor C21,
and the other end of the variable resistor R11 is connected to one
end of the resistor R21. A connecting point of the variable
resistor R11 and the resistor R21 is connected to a noninverting
input terminal of the amplifier AP21. The other end of the resistor
R21 is grounded. The output of the amplifier AP21 is connected to
an inverting input terminal of the amplifier AP21 and to a
connecting point of one end of the resistor R23 and one end of the
capacitor C23 of the phase correction circuit 523.
[0137] In the attenuator circuit 532, one end of the variable
resistor R12 is connected to the other end of the capacitor C22,
and the other end of the variable resistor R12 is connected to one
end of the resistor R22. A connecting point of the variable
resistor R12 and the resistor R22 is connected to a noninverting
input terminal of the amplifier AP22. The other end of the resistor
R22 is grounded. The output of the amplifier AP22 is connected to
an inverting input terminal of the amplifier AP22 and to a
connecting point of one end of the resistor R25 and one end of the
capacitor C24 of the phase correction circuit 533.
[0138] The phase correction circuit 523 includes the variable
resistor R13, the resistors R23 and R24, the capacitor C23, and the
amplifier AP23. The phase correction circuit 533 includes the
variable resistor R14, the resistors R25 and R26, the capacitor
C24, and the amplifier AP24.
[0139] In the phase correction circuit 523 of the embodiment, the
other end of the resistor R23 is connected to a noninverting input
terminal of the amplifier AP23, and a connecting point of the other
end of the capacitor C23 and one end of the variable resistor R13
is connected to an inverting input terminal of the amplifier AP23.
The other end of the variable resistor R13 is grounded. One end of
the resistor R24 is connected to the inverting input terminal of
the amplifier AP23, and the other end of the resistor R24 is
connected to the output of the amplifier AP23. The output of the
amplifier AP23 is connected to one end of the resistor R27 of the
adding circuit 540.
[0140] In the phase correction circuit 533 of the embodiment, the
other end of the resistor R25 is connected to a noninverting input
terminal of the amplifier AP24, and a connecting point of the other
end of the capacitor C24 and one end of the variable resistor R14
is connected to an inverting input terminal of the amplifier AP24.
The other end of the variable resistor R14 is grounded. One end of
the resistor R26 is connected to the inverting input terminal of
the amplifier AP24, and the other end of the resistor R26 is
connected to the output of the amplifier AP24. The output of the
amplifier AP24 is connected to one end of the resistor R28 of the
adding circuit 540.
[0141] The adding circuit 540 of the embodiment includes the
resistors R27 to R32, and the amplifiers AP25 and AP26. In the
adding circuit 540 of the embodiment, a connecting point of the
other end of the resistor R27 and the other end of the resistor R28
is connected to an inverting input terminal of the amplifier AP25.
One end of the resistor R29 is connected to a noninverting input
terminal of the amplifier AP25, and the other end of the resistor
R29 is grounded. The output of the amplifier AP25 is connected to
one end of the resistor R30. The other end of the resistor R30 is
connected to an inverting input terminal of the amplifier AP26. One
end of the resistor R31 is connected to a noninverting input
terminal of the amplifier AP26, and the other end of the resistor
R31 is grounded. One end of the resistor R32 is connected to the
inverting input terminal of the amplifier AP26, and the other end
of the resistor R32 is connected to the output of the amplifier
AP26. The output of the amplifier AP26 is connected to one end of
the resistor R35 of the subtracting circuit 560.
[0142] The buffer 550 of the embodiment includes the resistor R33
and the amplifier AP27. One end of the resistor R33 is connected to
the output of the piezo-electric sensor 191, and the other end of
the resistor R33 is grounded. A connecting point of the one end of
the resistor R33 and the output of the piezo-electric sensor 191 is
connected to a noninverting input terminal of the amplifier AP27.
The output of the amplifier AP27 is connected to an inverting input
terminal of the amplifier AP27 and one end of the resistor R34 of
the subtracting circuit 560.
[0143] The subtracting circuit 560 of the embodiment includes the
resistors R34 to R37, and the amplifier AP28. The other end of the
resistor R34 is connected to one end of the resistor R36. A
connecting point of the other end of the resistor R34 and the one
end of the resistor R36 is connected to a noninverting input
terminal of the amplifier AP28. The other end of the resistor R36
is grounded. The other end of the resistor R35 is connected to an
inverting input terminal of the amplifier AP28 and one end of the
resistor R37. The other end of the resistor R37 is connected to the
output of the amplifier AP28. The amplifier AP28 outputs a signal
from which the noise component is removed.
[0144] With reference to FIG. 13, a process of performing an
adjustment for removing the noise component from the output of the
piezo-electric sensor 191 in the optical scanner control apparatus
300 of the embodiment is explained. FIG. 13 is a flowchart showing
an example of a process of performing the adjustment for removing
the noise component of the fourth embodiment.
[0145] In this embodiment, by adjusting amplitudes and phases of
the first driving signal and the second driving signal, noise
equality components, which are equal to the noise components
generated by the first driving signal and the second driving
signal, are generated. In this embodiment, by subtracting the noise
equality components from the output of the piezo-electric sensor
191, the noise can be reduced.
[0146] Specifically, in this embodiment, the noise equality
components are generated from the first driving signal and the
second driving signal by adjusting the resistance values of the
variable resistors R11 and R12 of the noise attenuator circuits 522
and 532 and the resistance values of the variable resistors R13 and
R14 of the phase correction circuits 523 and 533, respectively. The
adjustment of the resistance values may be performed when the
optical scanner control apparatus 300 of the embodiment is shipped
from a factory of a manufacturer or the like, for example. Further,
the adjustment explained with reference to FIG. 13 may be manually
performed by a manufacturer or the like of the optical scanner
control apparatus 300, for example.
[0147] When the adjustment for removing the noise is performed in
the optical scanner control apparatus 300 of the embodiment, the
mirror control unit 430 is controlled to output only the first
driving signal (step S131). At this time, the frequency of the
first driving signal is set to be further away from a resonance
point so that the first horizontal driving source 151A is not
driven.
[0148] Subsequently, in this embodiment, the resistance value of
the variable resistor R11 of the attenuator circuit 522 and the
resistance value of the variable resistor R13 of the phase
correction circuit 523 are adjusted (step S132). In this
embodiment, by the adjustment in step S132, a first noise equality
component signal is generated from the first driving signal.
[0149] Subsequently, in this embodiment, the adjustment in step
S132 is repeated until the amplitude and the phase of the first
noise equality component signal becomes equal to the amplitude and
the phase of a first noise component output from the buffer 550
(step S133). The first noise component output from the buffer 550
is a noise component generated by the first driving signal. The
comparison of the first noise equality component signal and the
first noise component may be performed by connecting an
oscillograph or the like to a terminal T3, which is the output of
the buffer 550, and a terminal T1, which is the output of the phase
correction circuit 523, and observing the oscillograph or the like,
for example.
[0150] Subsequently, in this embodiment, for the second driving
signal, similar steps as step S131 to step S133 are performed. In
this embodiment, the mirror control unit 430 is controlled to
output only the second driving signal (step S134). At this time,
the frequency of the second driving signal is set to be further
away from a resonance point so that the second horizontal driving
source 151B is not driven. Subsequently, in this embodiment, the
resistance value of the variable resistor R12 of the attenuator
circuit 532 and the resistance value of the variable R14 of the
resistor phase correction circuit 533 are adjusted (step S135).
Subsequently, in this embodiment, by the adjustment in step S135, a
second noise equality component signal is generated from the second
driving signal. The adjustment in step S135 is repeated until the
amplitude and the phase of the second noise equality component
signal becomes equal to the amplitude and the phase of a second
noise component output from the buffer 550 (step S136).
[0151] The comparison of the second noise equality component signal
and the second noise component may also be performed by observing
the oscillograph or the like connected to the terminal T3, which is
the output of the buffer 550, and a terminal T2, which is the
output of the phase correction circuit 533.
[0152] Generation of the noise equality components is further
explained with reference to FIG. 14 to FIG. 16.
[0153] FIG. 14 is a view showing a waveform output from the
piezo-electric sensor 191 before removing the noise.
[0154] In FIG. 14, an oscillation displacement of the mirror 110 is
shown in (a). Waveforms of the first driving signal and the second
driving signal are shown in (c). The waveform output from the
piezo-electric sensor 191 when the first driving signal and the
second driving signal whose frequencies are further away from the
resonance point are applied to the first horizontal driving source
151A and the second horizontal driving source 151B, respectively,
is shown in (b). In (b), "N" expresses a noise component signal
generated by the first driving signal and the second driving
signal.
[0155] At this time, in the optical scanner apparatus 100, the
first horizontal driving source 151A and the second horizontal
driving source 151B are not oscillated and the mirror 110 is not
oscillated as well, as shown in (a). The component output from the
piezo-electric sensor 191 includes only the noise component signal
N, as shown in (b). In this embodiment, the noise component signal
N is removed.
[0156] FIG. 15A and FIG. 15B are views showing an example of noise
equality components. FIG. 15A shows an example of the first noise
equality component signal generated from the first driving signal.
FIG. 15B shows an example of the second noise equality component
signal generated from the second driving signal.
[0157] In FIG. 15A, a waveform output from the piezo-electric
sensor 191 when only the first driving signal is applied to the
first horizontal driving source 151A is shown in (b). At this time,
the component output from the piezo-electric sensor 191 includes
only a noise component signal N1 generated by the first driving
signal. A waveform of the first driving signal is shown in (c). A
waveform of the first noise equality component signal generated
from the first driving signal is shown in (a).
[0158] Similarly, in FIG. 15B, waveform output from the
piezo-electric sensor 191 when only the second driving signal is
applied to the second horizontal driving source 151B is shown in
(b). At this time, the component output from the piezo-electric
sensor 191 includes only a noise component signal N2 generated by
the second driving signal. A waveform of the second driving signal
is shown in (c). A waveform of the second noise equality component
signal generated from the second driving signal is shown in
(a).
[0159] In this embodiment, the noise component signal N (shown in
FIG. 14) is an added result of the noise component signal N1 shown
in (b) of FIG. 15A and the noise component signal N2 shown in (b)
of FIG. 15B.
[0160] In this embodiment, the gain-phase adjustment unit 520
adjusts the amplitude and the phase of the first driving signal to
generate the first noise equality component signal whose amplitude
and phase are the same as those of the noise component signal
N1.
[0161] In this embodiment, the gain-phase adjustment unit 530
adjusts the amplitude and the phase of the second driving signal to
generate the second noise equality component signal whose amplitude
and phase are the same as those of the noise component signal
N2.
[0162] Thus, in this embodiment, the noise component signal N shown
in FIG. 14 is an added result of the first noise equality component
signal and the second noise equality component signal. Therefore,
in this embodiment, by subtracting the noise component signal N
from the output of the piezo-electric sensor 191 when both the
first driving signal and the second driving signal are applied at
the same time, the noise component signal N can be cancelled.
[0163] FIG. 16 is a view showing a waveform output from the
piezo-electric sensor 191 after removing the noise.
[0164] In FIG. 16, similar to FIG. 14, an oscillation displacement
of the mirror 110 is shown in (a). Waveforms of the first driving
signal and the second driving signal are shown in (c). The waveform
output from a terminal T4, which is the output of the subtracting
circuit 560 in FIG. 12 when the first driving signal and the second
driving signal whose frequencies are further away from the
resonance point are applied to the first horizontal driving source
151A and the second horizontal driving source 151B, respectively,
is shown in (b).
[0165] As shown in (b) of FIG. 16, the noise component is not
included in the output of the piezo-electric sensor 191 when the
first driving signal and the second driving signal are applied at
the same time to the first horizontal driving source 151A and the
second horizontal driving source 151B, respectively.
[0166] Thus, according to the embodiment, a noise component which
is slightly generated by the length of the drive interconnects or a
space between the interconnects caused by the driving signals, for
example, can be removed. Thus, the inclination of the mirror can be
precisely detected by reducing the noise of the sensor
interconnects.
[0167] Further, in this embodiment, although the gain-phase
adjustment units 520 and 530 are explained to include the phase
correction circuits 523 and 533, respectively, the structures of
the gain-phase adjustment units 520 and 530 are not limited. For
example, when the phase of only one of the first driving signal and
the second driving signal is to be adjusted, only the respective
phase correction circuit may be included in the optical scanner
control apparatus 300.
[0168] FIG. 17 is a circuit diagram showing another example of a
circuit structure of a noise reduction unit 600A of the fourth
embodiment. In the example shown in FIG. 17, only the phase of the
first driving signal is adjusted. The noise reduction unit 600A
shown in FIG. 17 is different from the noise reduction unit 600
shown in FIG. 12 that the phase correction circuit 533
corresponding to the second driving signal is not included.
Further, for a case where only the phase of the second driving
signal is adjusted, the phase correction circuit 533 corresponding
to the second driving signal may be included and the phase
correction circuit 523 corresponding to the first driving signal
may not be included.
[0169] Further, although the structure in which the noise is
reduced when detecting the inclination of the mirror 110 in the
horizontal direction is explained in the above, the noise may be
reduced with a similar structure when the inclination of the mirror
110 in the vertical direction is detected.
Fifth Embodiment
[0170] The fifth embodiment is explained with reference to
drawings. The fifth embodiment is different from the fourth
embodiment that the adjustment for removing the noise is
automatically performed. In the following explanation, the same
components are given the same reference numerals, and explanations
are not repeated.
[0171] FIG. 18 is a block diagram showing an optical scanner
control apparatus 300A of the fifth embodiment. The optical scanner
control apparatus 300A of the embodiment includes a mirror driver
IC 500A. The mirror driver IC 500A includes a noise reduction
control unit 610 that automatically performs a process of
performing the adjustment for removing the noise component. The
noise reduction control unit 610 of the embodiment adjusts the
resistance values of the variable resistors or the like, as
explained in the fourth embodiment.
[0172] FIG. 19 is a flowchart showing an example of a process of
performing the adjustment for removing the noise component of the
fifth embodiment. In this embodiment, the amplitude and the phase
of the noise component signal N1 which is generated when only the
first driving signal is applied to the first horizontal driving
source 151A, and the amplitude and the phase of the noise component
signal N2 when only the second driving signal is applied to the
second horizontal driving source 151B are previously obtained as
target values.
[0173] In this embodiment, the noise reduction control unit 610
applies only the first driving signal to the first horizontal
driving source 151A (step S1601). Subsequently, the noise reduction
control unit 610 detects a level of the amplitude of the output of
the piezo-electric sensor 191 (which is the value output from the
terminal T1 as shown in FIG. 12) (step S1602). Subsequently, the
noise reduction control unit 610 detects a level of the amplitude
of the first noise equality component signal, which is the value
output from the terminal T1 as shown in FIG. 12 (step S1603).
Subsequently, the noise reduction control unit 610 determines
whether the amplitude of the first noise equality component signal
is equal to the amplitude of the noise component signal N1, which
is the target value (step S1604). The amplitude of the noise
component signal N1 is previously stored in a storing unit or the
like of the noise reduction control unit 610.
[0174] In step S1604, when the amplitude of the first noise
equality component signal is not equal to the amplitude of the
noise component signal N1 (NO in step S1604), the noise reduction
control unit 610 adjusts a gain of the attenuator circuit 522 (step
S1605). Specifically, the noise reduction control unit 610 adjusts
the resistance value of the variable resistor R11 of the attenuator
circuit 522.
[0175] The noise reduction control unit 610 of the embodiment
repeats the processes of step S1603 to step S1605 until the
amplitude of the first noise equality component signal becomes
equal to the amplitude of the noise component signal N1. In step
S1604, when the amplitude of the first noise equality component
signal is equal to the amplitude of the noise component signal N1
(YES in step S1604), the noise reduction control unit 610 sets the
resistance value at that time in the attenuator circuit 522 as a
resistance value for removing noise (step S1606).
[0176] Subsequently, the noise reduction control unit 610 detects
the phase of the output of the piezo-electric sensor 191 (step
S1607). Subsequently, the noise reduction control unit 610 detects
the phase of the first noise equality component signal (step
S1608).
[0177] Subsequently, the noise reduction control unit 610
determines whether the phase of the first noise equality component
signal is equal to the phase of the noise component signal N1,
which is the target value (step S1609). The phase of the noise
component signal N1 is previously stored in the storing unit or the
like of the noise reduction control unit 610.
[0178] In step S1609, when the phase of the first noise equality
component signal is not equal to the phase of the noise component
signal N1 (NO in step S1609), the noise reduction control unit 610
adjusts the phase of the first noise equality component signal by
the phase correction circuit 523 (step S1610). Specifically, the
noise reduction control unit 610 adjusts the resistance value of
the variable resistor R13 of the phase correction circuit 523.
[0179] The noise reduction control unit 610 of the embodiment
repeats the processes of step S1608 to step S1610 until the phase
of the first noise equality component signal becomes equal to the
phase of the noise component signal N1. In step S1609, when the
phase of the first noise equality component signal is equal to the
phase of the noise component signal N1 (YES in step S1609), the
noise reduction control unit 610 sets the resistance value at that
time in the phase correction circuit 523 as a resistance value for
removing noise (step S1611).
[0180] Subsequently, the noise reduction control unit 610 stops
providing the first driving signal and starts applying only the
second driving signal to the second horizontal driving source 151B
(step S1612).
[0181] The processes of step S1613 to step S1622 are the same as
the processes of step S1602 to step S1611, thus, the explanation is
not repeated.
[0182] By the processes from step S1602 to step S1622, the
resistance value of the variable resistor R12 of the attenuator
circuit 532 and the resistance value of the variable resistor R14
of the phase correction circuit 533 are set.
[0183] Subsequently, the noise reduction control unit 610 stores
the resistance values set in the variable resistors of the
attenuator circuits 522 and 532 and the resistance values set in
the variable resistors of the phase correction circuits 523 and 533
in the storing unit or the like of the noise reduction control unit
610 (step S1623).
[0184] As described above, in this embodiment, the process of
performing the adjustment for removing the noise component is
automatically performed.
Sixth Embodiment
[0185] The sixth embodiment is explained with reference to
drawings. This embodiment is different from the first embodiment
that two piezo-electric sensors for detecting the inclination of
the mirror 110 in the horizontal direction are provided. In the
following explanation, the same components are given the same
reference numerals, and explanations are not repeated.
[0186] FIG. 20 is a view showing an example of an optical scanner
apparatus 100C of the fifth embodiment where a mirror portion is
enlarged.
[0187] The optical scanner apparatus 100C of the embodiment
includes two piezo-electric sensors 191 and 192. In this
embodiment, the sensor signals of the piezo-electric sensors 191
and 192 are led to the second horizontal driving source 151B side,
and the drive interconnects for supplying the driving signals to
the first horizontal driving source 151A and the second horizontal
driving source 151B are led to the first horizontal driving source
151A side.
[0188] Further in this embodiment, the phase of the output of the
piezo-electric sensor 191 and the phase of the output of the
piezo-electric sensor 192 (an example of a fourth piezo-electric
sensor) are controlled to be opposite from each other.
[0189] In the optical scanner apparatus 100C of the embodiment, the
second drive interconnect for lower 205 for applying the driving
voltage to the lower electrode of the second horizontal driving
source 151B and the second drive interconnect for upper 206 for
applying the driving voltage to the upper electrode of the second
horizontal driving source 151B are led to the first horizontal
driving source 151A side. Further, the second drive interconnect
for lower 205 of the embodiment is connected to the lower electrode
of the first horizontal driving source 151A. Thus, the voltage
applied from the first drive interconnect for lower 203 is also
applied to the lower electrode of the second horizontal driving
source 151B via the first horizontal driving source 151A and the
second drive interconnect for lower 205. The second drive
interconnect for upper 206 is formed to extend along the first
drive interconnect for lower 203 and the first drive interconnect
for upper 204.
[0190] Further, in this embodiment, both the first sensor
interconnect 201 and the second sensor interconnect 202 connected
to the piezo-electric sensor 191 are formed at the second
horizontal driving source 151B side. Further, sensor interconnects
201A and 202A (an example of a seventh sensor interconnect and an
eighth sensor interconnect) connected to the upper electrode and
the lower electrode of the piezo-electric sensor 192, respectively,
are also led to the second horizontal driving source 151B side.
Then, the sensor interconnects 201A and 202A are formed to extend
along the first sensor interconnect 201 and the second sensor
interconnect 202.
[0191] In this embodiment, as shown in FIG. 20, the sensor
interconnects 201A and 202A and the first drive interconnect for
lower 203 and the first drive interconnect for upper 204 are
adjacent from each other only at a portion shown by dotted line
"S". It means that the length where the sensor interconnects are
close to the drive interconnects can be shortened to reduce the
crosstalk by the driving signals.
[0192] Further, in this embodiment, the sensor interconnects 201A
and 202A and the first sensor interconnect 201 and the second
sensor interconnect 202 are formed to extend along with each other.
Thus, the crosstalk components caused by the drive interconnects
can be equalized for all of the sensor interconnects.
[0193] Further, the piezo-electric sensor 191 and the
piezo-electric sensor 192 of the embodiment are provided close to
the beams which are oscillated by opposing phases from each other
while having the rotational shaft of the mirror 110 as a center,
respectively. Specifically, the piezo-electric sensor 191 is
connected to a left end portion of the connecting beam 140B while
the piezo-electric sensor 192 is connected to a right end portion
of the connecting beam 140B. The left end portion of the connecting
beam 140B is oscillated by the driving source 151B while the right
end portion of the connecting beam 140B is oscillated by the
driving source 151A. Thus, it means that the piezo-electric sensor
191 and the piezo-electric sensor 192 are provided at the beams
which are oscillated by the opposing phases from each other while
having the rotational shaft as a center.
[0194] FIG. 21 is a view showing an example of waveforms output
from the piezo-electric sensors 191 and 192 of the fifth
embodiment.
[0195] In FIG. 21, an oscillation displacement of the mirror 110 is
shown in (a). The waveforms output from the piezo-electric sensors
191 and 192 are shown in (b) and (c), respectively. In this
embodiment, the phase of the output of the piezo-electric sensor
191 is the same as that of the oscillation displacement, and the
phase of the output of the piezo-electric sensor 192 is opposite
from that of the output of the piezo-electric sensor 191.
[0196] In this embodiment, by providing the two piezo-electric
sensors 191 and 192 as described above, when the difference signal
of the outputs of the two piezo-electric sensors 191 and 192 is
obtained downstream of the optical scanner apparatus 100C, the
level of the output signal can be doubled, for example.
[0197] FIG. 22 is a view showing an example of a waveform of the
difference signal of the outputs of the piezo-electric sensors of
the fifth embodiment. In FIG. 22, an oscillation displacement of
the mirror 110 is shown in (a). The waveforms of the first driving
signal and the second signal are shown in (c). The difference
signal obtained by subtracting the output signal of the
piezo-electric sensor 192 from the output signal of the
piezo-electric sensor 191 is shown in (b). The difference signal
shown in (b) of FIG. 22 becomes double the output of each of the
piezo-electric sensors 191 and 192. Further, in this embodiment,
the output signal of the piezo-electric sensor can be magnified by
using the two piezo-electric sensor.
[0198] Thus, in this embodiment, even when the crosstalk generated
from the drive interconnects is superposed on the output of the
piezo-electric sensor, the amplitude of the output of the
piezo-electric sensor can be magnified enough to ignore the
crosstalk.
[0199] Further, the techniques explained in the fourth embodiment
and the fifth embodiment may be adapted to the sixth embodiment.
For example, in this embodiment, the noise component may be removed
from the output of the piezo-electric sensor 191 and the output of
the piezo-electric sensor 192.
Seventh Embodiment
[0200] The seventh embodiment is explained with reference to
drawings. In the seventh embodiment, a photo sensor for detecting
the inclination of the mirror is provided below the mirror 110 so
that the inclination of the mirror 110 can be precisely detected
without an influence of the noise of the sensor interconnects.
[0201] FIG. 23 is a block diagram showing an example of an optical
scanner control apparatus 300B of the seventh embodiment. The
optical scanner control apparatus 300B of the embodiment includes
the front end IC 400, the LD 440, a mirror driver IC 500A, and an
optical scanner module 100E.
[0202] The mirror driver IC 500A of the embodiment does not include
the buffer 570 included in the mirror driver IC 500 shown in FIG.
10 in the fourth embodiment.
[0203] The optical scanner module 100E of the embodiment includes
an optical scanner apparatus 100D and a photo sensor 700. The
optical scanner apparatus 100D does not include the piezo-electric
sensors 195 and 196 which detect the inclination of the mirror 110
in the vertical direction, the third sensor interconnect 207A and
the fourth sensor interconnect 208A included in the optical scanner
apparatus 100 shown in FIG. 1 to FIG. 3 in the first embodiment.
The photo sensor 700 detects the inclination of the mirror 110 in
the vertical direction. The output of the photo sensor 700 of the
embodiment is directly provided to the front end IC 400.
[0204] The optical scanner module 100E of the embodiment is
explained. FIG. 24 is a view showing an example of the optical
scanner module 100E of the seventh embodiment.
[0205] In the optical scanner module 100E of the embodiment, the
photo sensor 700 is provided below the optical scanner apparatus
100D. In this embodiment, a region including the mirror 110, the
mirror support portion 120, the first torsion beam 130A, the second
torsion beam 130B, the first connecting beam 140A, the second
connecting beam 140B, the first horizontal driving beam 150A, the
second horizontal driving beam 150B, and the movable frame 160 are
assumed as a movable unit K of the optical scanner apparatus 100D.
The photo sensor 700 is positioned below the optical scanner
apparatus 100D such that a part of the photo sensor 700 is
overlapped with a part of the movable unit K.
[0206] FIG. 25 is a side view of the optical scanner module 100E of
the seventh embodiment. FIG. 25 is a cross-sectional view of the
optical scanner module 100E taken along an A-A line in FIG. 24. In
the optical scanner module 100E, the optical scanner apparatus 100D
is fixed to a ceramics package 710 and the photo sensor 700 is
positioned between the ceramics package 710 and the optical scanner
apparatus 100D. Under this condition, as shown in FIG. 24, the
photo sensor 700 is positioned such that a part of the photo sensor
700 is overlapped with a part of the movable unit K of the optical
scanner apparatus 100D.
[0207] The photo sensor 700 of the embodiment includes a light
emitting element and a light receiving element. A part of the light
emitted from the light emitting element is reflected by the movable
unit K, for example. The movable unit K is oscillated in accordance
with the inclination of the mirror 110 which is oscillated by the
four driving sources, the first horizontal driving source 151A, the
second horizontal driving source 151B, the first vertical driving
source 171A and the second vertical driving source 171B. Thus, a
position to which the light emitted from the light emitting element
is irradiated in the movable unit K is oscillated in accordance
with the inclination of the mirror 110. Therefore, the amount of
the light returned to the light receiving element from the light
emitting element varies in accordance with the inclination of the
movable unit K. The photo sensor 700 of the embodiment detects the
inclination of the mirror 110 in the vertical direction based on
the amount of the light returned to the light receiving
element.
[0208] FIG. 26 is a view for explaining an example of the photo
sensor 700. The photo sensor 700 of the embodiment includes a
photodiode 720 which is the light emitting element and a
phototransistor 730 which is the light receiving element. The photo
sensor 700 of the embodiment may be packaged, for example.
[0209] The position of the photo sensor 700 of the embodiment is
explained. FIG. 27 is a view showing a position of the photo sensor
700.
[0210] The photo sensor 700 of the embodiment includes the light
emitting element and the light receiving element and positioned
below the optical scanner apparatus 100D, as explained above.
[0211] The photo sensor 700 of the embodiment is positioned such
that a part of the photo sensor 700 is overlapped with a part of
the movable unit K. A part of the light emitted from the light
emitting element 720 of the photo sensor 700 is shut by the movable
unit K when the mirror 110 is not inclined in the vertical
direction. Then, when the mirror 110 is inclined in the vertical
direction, the amount of the light emitted from the light emitting
element 720 and shut (reflected) by the movable unit K decreases so
that the amount of the light returned to the light receiving
element 730 decreases. In this embodiment, the photo sensor 700 may
be positioned at a position where the light emitted from the light
emitting element 720 is not shut by the movable unit K at all when
the inclination of the mirror 110 in the vertical direction becomes
the maximum.
[0212] Further in this embodiment, the photo sensor 700 may be
positioned such that the light emitting element 720 and the light
receiving element 730 are aligned in an X1-X2 direction shown in
FIG. 27 in the photo sensor 700. Further, at this time, the center
of an external diameter of the photo sensor 700 and a center axis
of the mirror 110 may match with each other. Further, the photo
sensor 700 of the embodiment may be positioned to be overlapped at
portions with the fixed frame 180.
[0213] The photo sensor 700 of the embodiment is positioned such
that the output of the photo sensor 700 becomes the closest to an
actual value of the inclination of the mirror 110.
[0214] A method of determining the position of the photo sensor 700
is explained. In this embodiment, the position of the photo sensor
700 is moved in a Y2-Y1 direction while assuming a position at
which a distance between an end surface El of the inside of the
fixed frame 180 to an end surface E2 of the photo sensor 700 facing
the mirror 110 is 600 .mu.m as a initial position under a condition
that the external diameter of the photo sensor 700 and the center
axis of the mirror 110 match with each other. Then, the output of
the photo sensor 700 and the actual value are compared for each of
the positions to find a position where the output of the photo
sensor 700 becomes the closest or substantially equal to the actual
value as the position of the photo sensor 700.
[0215] A measurement of the actual value of the inclination of the
mirror 110 in the vertical direction is explained. FIG. 28 is a
view for explaining measuring the inclination of the mirror in the
vertical direction.
[0216] In this embodiment, the optical scanner module 100E is
provided in a measurement apparatus 280. Then, the light emitted
from the LD (Laser Diode) 281 is irradiated on the oscillated
mirror 110 to have a Position Sensitive Detector (PSD) 282 receive
the reflected light from the LD 281. The voltage in accordance with
the amount of lights output from the PSD 282 is the actual value
indicating the inclination of the mirror 110 in the vertical
direction (displacement).
[0217] A comparison result between the actual value and the output
of the photo sensor 700 is explained. FIG. 29 is a view showing an
example of a comparison result between the actual value and the
output of the photo sensor 700.
[0218] FIG. 29 shows a case in which the photo sensor 700 is
positioned 550 .mu.m away from the initial position in the Y1
direction (see FIG. 27). In FIG. 29, the distance H between the end
surface E1 of the fixed frame 180 and the end surface E2 of the
photo sensor 700 becomes 600 .mu.m+550 .mu.m. At this time, the
photo sensor 700 is positioned such that a part of the photo sensor
700 overlaps a part of the movable frame 160 in the Y2 direction
side. In FIG. 29, although there is a slight difference between
peaks of the output of the PSD 282 (actual value) shown by the
dotted line and peaks of the output of the photo sensor 700 shown
by the solid line, it can be understood that the output of the
photo sensor 700 has substantially the same shape as that of the
actual value. Thus, in this embodiment, the photo sensor 700 may be
positioned such that the distance H=600 .mu.m+550 .mu.m, in other
words, a position where a part of the photo sensor 700 overlaps a
part of the movable frame 160 in the Y2 direction side.
[0219] FIG. 30 is a view showing another example of a comparison
result between the actual value and the output of the photo sensor
700. FIG. 30 shows a case in which the photo sensor 700 is
positioned 1000 .mu.m away from the initial position in the Y1
direction (see FIG. 27). In FIG. 30, the distance H between the end
surface E1 of the fixed frame 180 and the end surface E2 of the
photo sensor 700 becomes 600 .mu.m+1000 .mu.m. At this time, the
photo sensor 700 is positioned such that a part of the photo sensor
700 overlaps a part of the mirror 110. In FIG. 30, although there
is a slight difference between peaks of the output of the PSD 282
(actual value) shown by the dotted line and peaks of the output of
the photo sensor 700 shown by the solid line, it can be understood
that the output of the photo sensor 700 has substantially the same
shape as that of the actual value. Thus, in this embodiment, the
photo sensor 700 may be positioned such that the distance H=600
.mu.m+1000 .mu.m, in other words, a position where a part of the
photo sensor 700 overlaps a part of the mirror 110.
[0220] FIG. 31 is a view showing another example of a comparison
result between the actual value and the output of the photo sensor
700. FIG. 31 shows a case in which the photo sensor 700 is
positioned 3850 .mu.m away from the initial position in the Y1
direction (see FIG. 27). In FIG. 31, the distance H between the end
surface E1 of the fixed frame 180 and the end surface E2 of the
photo sensor 700 becomes 600 .mu.m+3850 .mu.m. At this time, the
photo sensor 700 is positioned such that a part of the photo sensor
700 overlaps a part of the movable frame 160 in the Y1 direction
side.
[0221] At this time, the output of the photo sensor 700 becomes a
signal having an opposite phase as that of the output of the photo
sensor 700 when the photo sensor 700 is positioned to overlap a
part of the movable frame 160 in the Y2 direction side. Thus, for
the case shown in FIG. 31, a signal obtained by reversing the phase
of the output of the photo sensor 700 is used as the output of the
photo sensor 700 to be compared with the actual value.
[0222] In FIG. 31, the output of the PSD 282 (actual value) shown
by a dotted line, and the output of the photo sensor 700 shown by a
solid line substantially match with each other. Further, for the
case shown in FIG. 31, it can be understood that the output of the
photo sensor 700 is closer to the actual value compared with the
cases shown in FIG. 29 and FIG. 30 when comparing the overlaps of
the outputs of the photo sensor 700 and the actual values,
respectively. In the optical scanner module 100D of the embodiment,
the movable frame 160 in the Y1 direction side functions as an
axial shaft when the mirror 110 is oscillated in the vertical
direction. In this embodiment, it can be understood from the
results shown in FIG. 29 to
[0223] FIG. 31 that the inclination of the mirror 110 can be more
precisely detected when the photo sensor 700 is positioned closer
to the movable frame 160 which functions as the axial shaft for
oscillation in the vertical direction.
[0224] Thus, in this embodiment, the photo sensor 700 may be
positioned such that the distance H=600 .mu.m+3850 .mu.m, in other
words, at a position where a part of the photo sensor 700 overlaps
a part of the movable frame 160 in the Y1 direction side.
[0225] Further, although this embodiment is assumed that the photo
sensor 700 is positioned on a center axis of the mirror 110, this
embodiment is not so limited. For example, the photo sensor 700 may
be positioned such that a part of the photo sensor 700 overlaps
parts of the mirror 110 and the first horizontal driving beam 150A
or such that a part of the photo sensor 700 overlaps parts of the
mirror 110 and the second horizontal driving beam 150B. The photo
sensor 700 may be positioned such that a part of the photo sensor
700 overlaps a part of the mirror 110.
[0226] The photo sensor 700 of the embodiment may be positioned at
any place in the movable unit K provided that it can be determined
that the inclination of the mirror 110 can be sufficiently
precisely detected when compared with the actual value.
[0227] As described above, in this embodiment, by using the photo
sensor 700 instead of the piezo-electric sensor when detecting the
inclination of the vertical direction of the mirror 110, it is not
necessary to care for the noise of the sensor interconnects and the
inclination of the mirror can be precisely detected.
[0228] According to the embodiments, the inclination of the mirror
can be precisely detected by reducing the noise of the sensor
interconnects.
[0229] Although a preferred embodiment of the optical scanner
apparatus or the optical scanner control apparatus has been
specifically illustrated and described, it is to be understood that
minor modifications may be made therein without departing from the
sprit and scope of the invention as defined by the claims.
[0230] The present invention is not limited to the specifically
disclosed embodiments, and variations and modifications may be made
without departing from the scope of the present invention.
[0231] The present application is based on Japanese Priority
Application No. 2011-219255 filed on Oct. 3, 2011, and Japanese
Priority Application No. 2012-152834 filed on Jul. 6, 2012, the
entire contents of which are incorporated herein by reference.
* * * * *