The invention provides an angular-velocity detection apparatus, which includes a substrate (22) and a vibrating body (26) provided on the substrate (22), the vibrating body (26) being capable of displacing in a vibration axis direction and a detection axis direction which intersect at right angles to each other. A vibration generation section (33) is provided for vibrating the vibrating body (26) in the vibration axis direction by applying a driving signal, and a displacement detection section (34) is provided for detecting the amount of displacement of the vibrating body (26) when the vibrating body (26) is displaced in the detection axis direction on the basis of the angular velocity along a detected axis intersecting at right angles to the vibration axis and the detection axis in a state of the vibrating body (26) being vibrated in the vibration axis direction by the vibration generation direction (33). A corrective-vibration generation (35) is provided for causing the vibrating body (26) to vibrate for correction in the detection axis direction, thereby making it possible to reduce leakage vibration applied to the vibrating body (26) and to accurately detect the angular velocity .OMEGA..

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an angular-velocity detection apparatus 
which is suitably used to detect an angular velocity applied to, for 
example, a rotation member. More particularly, this invention provides an 
angular-velocity detection apparatus comprising a substrate, a vibrating 
body provided on the substrate, the vibrating body being capable of 
displacing in a vibration axis direction and a detection axis direction 
which intersect at right angles to each other, vibration generation means 
for vibrating the vibrating body in the vibration axis direction by 
applying a driving signal, and displacement detection means for detecting 
the amount of displacement of the vibrating body when the vibrating body 
is displaced in the detection axis direction on the basis of the angular 
velocity along a detected axis intersecting at right angles to the 
vibration axis and the detection axis in a state of the vibrating body 
being vibrated in the vibration axis direction by the vibration generation 
means. 
2. Description of the Related Art 
Generally, in angular-velocity detection apparatus, when a rotational force 
is applied about a Z axis which serves as a detected axis in a state in 
which a vibrating body is vibrated in the direction of a vibration axis in 
the three axes of X, Y and Z axes, a Coriolis force (inertial force) acts 
on the vibrating body, causing the vibrating body to vibrate in the 
direction of the Y axis which serves as a detection axis. Angular velocity 
detection apparatus which detect the displacement of the vibrating body in 
the direction of the Y axis due to this Coriolis force as an electrical 
charge generated in a piezoelectric member or as a change in a voltage, 
electrostatic capacitance or the like. Such an angular-velocity detection 
apparatus is disclosed in, for example, Japanese Unexamined Patent 
Publication (laid-open) No. 6-123632 (hereinafter referred to as "the 
prior art") is known. 
An explanation of the prior art will now be given with reference to FIGS. 7 
and 8. 
In FIGS. 7 and 8, reference numeral 1 denotes an angular-velocity detection 
element of the prior art. Reference numeral 2 denotes a substrate formed 
in a rectangular shape, which forms the main body of the angular-velocity 
detection element 1, with the substrate 2 being formed of, for example, a 
high-resistance silicon material. 
Reference numeral 3 denotes a movable section formed of low-resistance 
polysilicon, single-crystal silicon or the like having doped P, B, Sb or 
the like onto the substrate 2. The movable section 3 is formed of four 
support sections 4, 4, . . . provided on the substrate 2 so as to be 
positioned at the four corners of the substrate 2, four support beams 5, 
5, . . . which are formed bent in the shape of the letter L in such a 
manner as to have a portion parallel to the X axis and a portion parallel 
to the Y axis from each support section 4 toward the central portion, and 
a rectangular vibrating body 6 which is supported by each support beam 5 
in such a manner as to be capable of displacing in the X-axis and Y-axis 
directions and which is supported spacedly apart from the surface of the 
substrate 2. Electrodes 7 and 7 for vibration on the movable side, having 
provided therein a plurality of electrode plates 7A, 7A, . . . (four) in 
the shape of a comb, are protrusively provided on both siles of the left 
and right of the vibrating body 6, which is in the X-axis direction, and 
electrodes 8 and 8 for detection on the movable side, having provided 
therein a plurality of electrode plates 8A, 8A, . . . (four) in the shape 
of a comb, are protrusively provided on both siles of the front and back 
thereof, which is in the Y-axis direction. 
In the movable section 3, only each support section 4 is fixedly secured to 
the substrate 2, and each support beam 5 and the vibrating body 6 are 
supported at four point in a state spaced apart by a predetermined amount 
from the substrate 2. Further, since each support beam 5 is formed in the 
shape of the letter L, by flexing the portion parallel to the Y axis, the 
vibrating body 6 can be displaced in the X-axis direction, and by flexing 
the portion parallel to the X axis, the vibrating body 6 can be displaced 
in the Y-axis direction. 
Reference numerals 9 and 9 denote a pair of electrodes for vibration on the 
fixation side, provided on the substrate 2 in such a manner as to sandwich 
the vibrating body 6 from both sides of the right and left thereof. Each 
electrode 9 for vibration on the fixation side is formed of fixation 
sections 9A and 9A provided on the substrate 2 in such a manner as to be 
positioned on the right and left of the vibrating body 6, and four 
electrode plates 9B, 9B, . . . protrusively provided in the shape of a 
comb from each fixation section 9A in such a manner as to face with a gap 
each electrode plate 7A of the electrode 7 for vibration on the movable 
side. 
Reference numerals 10 and 10 denote a pair of electrodes for detection on 
the fixation side, which are provided on the substrate 2 in such a manner 
as to sandwich the vibrating body 6 from both sides of the front and back 
thereof. Each electrode 10 for detection on the fixation side is formed of 
fixation sections 10A and 10A provided on the substrate 2 in such a manner 
as to be positioned on the front and back of the vibrating body 6, and 
four electrode plates 10B, 10B, . . . protrusively provided in the shape 
of a comb from each fixation section 10A in such a manner as to face with 
a gap each electrode plate 8A of the electrode 8 for detection on the 
movable side. 
Reference numerals 11 and 11 denote vibration generation sections which 
serve as vibration generation means. Each vibration generation section 11 
is formed of the electrode 7 for vibration on the movable side and the 
electrode 9 for vibration on the fixation side, with an equal gap being 
formed between each electrode plate 7A of the electrode 7 for vibration on 
the movable side and each electrode plate 9B of the electrode 9 for 
vibration on the fixation side. Here, if a driving signal of a frequency f 
at an opposite phase is applied between each electrode 7 for vibration on 
the movable side and each electrode 9 for vibration on the fixation side, 
an electrostatic attraction force is generated alternately between each 
electrode plate 7A and each electrode plate 9B positioned at left and 
between each electrode plate 7A and each electrode plate 9B positioned at 
right, and they come close to each other or move away from each other in 
each vibration generation section 11. This causes the vibrating body 6 to 
vibrate in the direction of the arrow a which is the X axis. 
Reference numerals 12 and 12 denote displacement detection sections which 
serve as displacement detection means. Each displacement detection section 
12 is formed of an electrode 8 for detection on the movable side and an 
electrode 10 for detection on the fixation side, with a facing length L0 
being formed between each electrode plate 8A of the electrode 8 for 
detection on the movable side and each electrode plate 10B of the 
electrode 10 for detection on the fixation side. The electrodes 8 and 10 
for detection are structured as parallel-plate capacitors for detection, 
and each displacement detection section 12 detects a change in the 
effective area between each electrode plate 8A and each electrode plate 
10B as a change in the electrostatic capacitance. 
In the angular-velocity detection element 1 structured as described above, 
if a driving signal of a frequency f at an opposite phase is applied to 
each vibration generation section 11, an electrostatic-attraction force 
alternately acts on the right and left vibration generation sections 11 
and 11 between each electrode plate 7A and each electrode plate 9B, 
causing the vibrating body 6 to come close or move away in the direction 
of the arrow a and to vibrate. 
In this state, when an angular velocity .OMEGA. about the Z axis is applied 
to the angular-velocity detection element 1, a Coriolis force (inertial 
force) is generated in the Y-axis direction, causing the vibrating body 6 
to vibrate in the Y-axis direction by a Coriolis force F shown below at 
equation (2). 
Here, a displacement x at which the vibrating body 6 is moved in the X-axis 
direction by each vibration generation section 11 and its velocity V are 
as in equation (1) below: 
EQU x=A sin(.omega.t) 
EQU V=A.omega. cos(.omega.t) (1) 
where A is the amplitude of the vibrating body 6, .omega. is 2.pi.f, and f 
is the frequency of the driving signal. 
Further, the Coriolis force F in the Y-axis direction generated from the 
angular velocity .OMEGA. applied about the Z axis when the vibrating body 
6 is vibrated in the X-axis direction at a displacement x and velocity V 
is as in equation (2) below: 
##EQU1## 
Then, the vibrating body 6 is vibrated in the direction of the Y axis by 
the Coriolis force F of equation (2), and the vibration displacement by 
this vibrating body 6 is detected by each displacement detection section 
12 as the change of the electrostatic capacitance between the electrode 8 
for detection on the movable side and the electrode 10 for detection on 
the fixation side, making it possible to detect the angular velocity 
.OMEGA. about the Z axis. 
Since each vibration generation section 11 is formed of the electrode 7 for 
vibration on the movable side formed of each electrode plate 7A and the 
electrode 9 for vibration on the fixation side formed of each electrode 
plate 9B, it is possible to secure a large effective area where the 
electrodes 7 and 9 for vibration face each other. As a result, when a 
driving signal is applied to each vibration generation section 11, an 
electrostatic attraction force generated between each electrode plate 7A 
and each electrode plate 9B is increased to vibrate the vibrating body 6 
in the direction of the arrow a. 
Meanwhile, since each displacement detection section 12 is formed of the 
electrode 8 for detection on the movable side formed of each electrode 
plate 8A and the electrode 10 for detection on the fixation side formed of 
each electrode plate 10B, it is possible to increase the effective area 
where the electrodes 8 and 10 for detection face each other. As a result, 
it is possible to detect the amount of the displacement of the vibrating 
body 6 which is displaced in the Y-axis direction by each displacement 
detection section 12 as a change in the effective area between each 
electrode plate 8A and each electrode plate 10B, i.e., a change in the 
electrostatic capacitance. 
In the above-described angular-velocity detection element 1 of the prior 
art, the Coriolis force generated by the angular velocity .OMEGA. about 
the Z axis is very small, and therefore, it is necessary to generate a 
large displacement by using the resonance in the Y-axis direction. 
Meanwhile, to increase the Coriolis force, as even can be understood from 
equation (2), since the velocity V during vibration must be increased, a 
frequency near the resonance frequency in the X-axis direction is used as 
the frequency of the driving signal. Therefore, reaching a state close to 
the resonance frequency even at the vibration conditions in the Y-axis 
direction which serves as a detection axis is required to increase 
sensitivity. 
However, if the resonance frequency in the detection direction is made to 
come close to the resonance frequency in the driving direction as 
described above, a part of the driving signal leaks (what is commonly 
called crosstalk) in the detection direction via the parasitic capacitance 
of the substrate 2 or the like. Then, this driving signal which leaked is 
applied to each displacement detection section 12, an electrostatic 
attraction force is generated between the electrode 8 for detection on the 
movable side and the electrode 10 for detection on the fixation side, and 
even in a state in which the angular velocity .OMEGA. does not act, 
vibration (hereinafter referred to as leakage vibration) appears in the 
vibrating body 6, presenting a problem of causing noise. 
SUMMARY OF THE INVENTION 
The object of the present invention is to overcome the above-described 
problems of the prior art by providing an angular-velocity detection 
apparatus which is capable of eliminating components which may cause noise 
and increasing the angular-velocity detection accuracy. 
The invention provides an angular-velocity detection apparatus of the above 
mentioned kind, which is characterized in that corrective-vibration 
generation means for causing the vibrating body to vibrate for correction 
in the detection axis direction is provided. 
With the above angular-velocity detection apparatus, even when a leakage 
vibration occurs by which the vibrating body is displaced in the 
detection-axis direction due to the influence of a driving signal applied 
to the vibration generation means when an angular velocity is not applied 
about the detected axis, it is possible to suppress the leakage vibration 
of the vibrating body in the detection-axis direction by generating a 
corrective-vibration which opposes a leakage vibration of the vibrating 
body. The corrective-vibration is generated by applying a correction 
signal to the corrective-vibration generation means. 
In the above angular-velocity detection apparatus, a correction signal 
applied to the corrective-vibration generation means may have the same 
frequency as that of the driving signal applied to the vibration 
generation means and may have a phase different from that of the driving 
signal. Further, the correction signal may have an amplitude different 
from that of the driving signal. 
As in the above angular-velocity detection apparatus, when an angular 
velocity is not applied about the detected axis, a leakage vibration which 
occurs in the vibrating body is generated by the driving signal applied to 
the vibration generation means. Therefore, by inputting a correction 
signal which has the same frequency as that of the driving signal and 
which is at a phase different from the driving signal, it is possible to 
cancel the leakage vibration by the corrective-vibration which occurs in 
the vibrating body. 
In the above angular-velocity detection apparatus, there may be provided 
that self-diagnostic means which causes the vibrating body to displace in 
the detection axis direction by inputting the correction signal and 
determines whether or not the vibrating body operates normally on the 
basis of a relationship between the correction signal and the displacement 
of the vibrating body in the detection axis direction when it is 
determined that an angular velocity is not applied on the basis of a 
detection signal from the displacement detection means. 
As in the above angular-velocity detection apparatus, when it is determined 
that an angular velocity has not been applied, the vibrating body is 
displaced in the detection-axis direction by the correction signal input 
to the corrective-vibration generation means, and this displacement is 
detected by the displacement detection means. Then, the self-diagnostic 
means determines whether or not the displacement of this vibrating body in 
the detection-axis direction falls within the preset displacement range in 
which the vibrating body is assumed to be normal, and is able to perform a 
self-diagnosis of whether the vibrating body is operating normally. 
The above and further objects, aspects and novel features of the invention 
will become more apparent from the following detailed description when 
read in connection with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the description of the embodiments, components which are the same as 
those of the prior art are given the same reference numerals and 
therefore, a description thereof has been omitted. 
First, FIGS. 1 through 4 show a first embodiment of the present invention. 
Reference numeral 21 denotes an angular-velocity detection element which 
constitutes an angular-velocity detection apparatus in accordance with 
this embodiment. Reference numeral 22 denotes a substrate formed in a 
rectangular shape, which forms the main body of the angular-velocity 
detection element 21, with the substrate 22 being formed of, for example, 
a high-resistance silicon material. 
Reference numeral 23 denotes a movable section formed of low-resistance 
polysilicon, single-crystal silicon or the like having doped P, B, Sb or 
the like onto the substrate 22. The movable section 23, substantially 
similar to the movable section 3 of the prior art, is formed of four 
support sections 24, 24, . . . provided on the substrate 22 so as to be 
positioned at the four corners of the substrate 22, four support beams 25, 
25, . . . which are formed bent in the shape of the letter S in such a 
manner as to have a portion parallel to the X axis and a portion parallel 
to the Y axis from each support section 24 toward the central portion, and 
a rectangular vibrating body 26 which is supported by each support beam 25 
in such a manner as to be capable of displacing in the X-axis and Y-axis 
directions and which is supported spacedly apart from the surface of the 
substrate 22. Electrodes 27 and 27 for vibration on the movable side, 
having provided therein a plurality of electrode plates 27A, 27A, . . . 
(five) in the shape of a comb, are protrusively provided in the rear 
portion on both sides of the left and right of the vibrating body 26, 
which is in the X-axis direction, and electrodes 28 and 28 for detection 
on the movable side, having provided therein a plurality of electrode 
plates 28A, 28A, . . . (four) in the shape of a comb, are protrusively 
provided in the front portion on both sides of the front and back of the 
vibrating body 26, which is in the Y-axis direction. Further, electrodes 
29 and 29 for corrective vibration on the movable side, having provided 
therein a plurality of electrode plates 29A, 29A, . . . (four) in the 
shape of a comb, are protrusively provided on both sides of the left and 
right, which is in the Y-axis direction. 
Then, in the movable section 23, only each support section 24 is fixedly 
secured to the substrate 22, and each support beam 25 and the vibrating 
body 26 are supported at four points in a state spaced apart by a 
predetermined amount from the substrate 22. Further, since each support 
beam 25 is formed in the shape of the letter S, by flexing the portion 
parallel to the Y axis, the vibrating body 26 can be displaced in the 
X-axis direction, and by flexing the portion parallel to the X axis, the 
vibrating body 26 can be displaced in the Y-axis direction. 
Reference numerals 30 and 30 denote a pair of electrodes for vibration on 
the fixation side, provided on the substrate 22 in such a manner as to be 
positioned in the rear portion of both sides of the right and left of the 
vibrating body 26 and sandwich the vibrating body 26. Each electrode 30 
for vibration on the fixation side is formed of fixation sections 30A and 
30A provided on the substrate 22 in such a manner as to be positioned on 
the right and left of the vibrating body 26, and six electrode plates 30B, 
30B, . . . protrusively provided in the shape of a comb from each fixation 
section 30A in such a manner as to face with a gap each electrode plate 
27A of the electrode 27 for vibration on the movable side. 
Reference numerals 31 and 31 denote a pair of electrodes for detection on 
the fixation side, provided on the substrate 22 in such a manner as to be 
positioned in the front portion of both sides of the right and left of the 
vibrating body 26 and sandwich the vibrating body 26. Each electrode 31 
for detection on the fixation side is formed of fixation sections 31A and 
31A provided on the substrate 22 in such a manner as to be positioned on 
the right and left of the vibrating body 26, and four electrode plates 
31B, 31B, . . . protrusively provided in the shape of a comb from each 
fixation section 31A in such a manner as to face with a gap each electrode 
plate 28A of the electrode 28 for detection on the movable side. 
Reference numerals 32 and 32 denote a pair of electrodes for corrective 
vibration on the fixation side, provided on the substrate 22 in such a 
manner as to be positioned on both sides of the front and back of the 
vibrating body 26 and sandwich the vibrating body 26. Each electrode 32 
for corrective vibration on the fixation side is formed of fixation 
sections 32A and 32A provided on the substrate 22 in such a manner as to 
be positioned on the front and back of the vibrating body 26, and five 
electrode plates 32B, 32B, . . . protrusively provided in the shape of a 
comb from each fixation section 32A in such a manner as to face with a gap 
each electrode plate 29A of the electrode 29 for corrective vibration on 
the movable side. 
Reference numerals 33 and 33 denote vibration generation sections which 
serve as vibration generation means. Each vibration generation section 33 
is formed of the electrode 27 for vibration on the movable side and the 
electrode 30 for vibration on the fixation side, with an equal gap being 
formed between each electrode plate 27A of the electrode 27 for vibration 
on the movable side and each electrode plate 30B of the electrode 30 for 
vibration on the fixation side. Here, if a driving signal Vd of a 
predetermined frequency f at an opposite phase is applied between each 
electrode 27 for vibration on the movable side and each electrode 30 for 
vibration on the fixation side, an electrostatic attraction force is 
generated alternately between each electrode plate 27 and each electrode 
plate 30 positioned at left and between each electrode plate 27A and each 
electrode plate 30B positioned at right, and they come close to each other 
or move away from each other in each vibration generation section 33. This 
causes the vibrating body 26 to vibrate in the direction of the arrow a 
which is the X axis. 
Reference numerals 34 and 34 denote displacement detection sections which 
serve as displacement detection means. Each displacement detection section 
34 is formed of the electrode 28 for detection on the movable side and an 
electrode 31 for detection on the fixation side, with a different adjacent 
gap dimension being formed between each electrode plate 28A of the 
electrode 28 for detection on the movable side and each electrode plate 
31B of the electrode 31 for detection on the fixation side. The electrodes 
28 and 31 for detection are structured as parallel-plate capacitors for 
detection, and each displacement detection section 34 detects a change in 
the effective distance between each electrode plate 28A and each electrode 
plate 31B as a change in the electrostatic capacitance. 
Reference numerals 35 and 35 denote corrective-vibration generation 
sections which serve as corrective-vibration generation means. Each 
corrective vibration generation section 35 is formed of the electrode 29 
for corrective vibration on the movable side and the electrode 32 for 
corrective vibration on the fixation side, with an equal gap being formed 
between each electrode plate 29A of the electrode 29 for corrective 
vibration on the movable side and each electrode plate 32B of the 
electrode 32 for corrective vibration on the fixation side. Here, by 
inputting a correction signal Vr having the same frequency as that of the 
driving signal Vd between each electrode 29 for corrective vibration on 
the movable side and each electrode 32 for corrective vibration on the 
fixation side in order to cause an electrostatic attraction force to be 
generated alternately between each electrode plate 29A and each electrode 
plate 32B, the vibrating body 26 can be corrective-vibrated in the Y-axis 
direction. 
Next, referring to FIG. 3, the construction of an electrical circuit added 
to the angular-velocity detection element 21 will be described. 
In FIG. 3, reference numeral 36 denotes a driving circuit. The driving 
circuit 36 is formed of an vibrating body which generates a sine wave of a 
predetermined frequency f and an amplifier circuit which adjusts the 
amplitude of a sine wave. Here, a driving signal Vd of a frequency f is 
applied to the vibration generation section 33. The applied driving signal 
Vd acts on the electrode 27 for vibration on the movable side and the 
electrode 30 for vibration on the fixation side, which constitute the 
vibration generation section 33, and the electrostatic attraction force 
between each electrode plate 27A and each electrode plate 30B causes the 
vibrating body 26 to vibrate in the vibration-axis (X axis) direction. The 
driving circuit 36 is capable of adjusting the amplitude of the vibrating 
body 26 in the vibration-axis direction by adjusting the amplitude of the 
driving signal Vd. 
Reference numeral 37 denotes a displacement-amount detection circuit. The 
displacement-amount detection circuit 37 detects the displacement of the 
vibrating body 26 in the detection-axis (Y axis) direction, namely, a 
change in the spacing dimension between the electrode 28 for detection on 
the movable side and the electrode 31 for detection on the fixation side, 
which constitute the displacement detection section 34, as a change in the 
electrostatic capacitance and converts this detection signal into a 
voltage. 
Reference numeral 38 denotes an angular-velocity signal conversion circuit, 
with the driving circuit 36 and the displacement-amount detection circuit 
37 being connected to the input side of the angular-velocity signal 
conversion circuit 38. The angular-velocity signal conversion circuit 38 
corrects the deviation of the phase or the like on the basis of the 
driving signal Vd output from the driving circuit 36 and the detection 
signal output from the displacement-amount detection circuit 37 and 
outputs the signal as an output signal Vo corresponding to the angular 
velocity .OMEGA. to an external source. 
Reference numeral 39 denotes a correction driving circuit. The correction 
driving circuit 39 applies to the corrective-vibration generation section 
35 a correction signal Vr whose phase is shifted at a frequency f in 
accordance with a signal output from an offset adjustment circuit 40, 
which will be described later. The correction signal Vr input to the 
corrective-vibration generation section 35 becomes a waveform reverse to 
the amplitude of the leakage vibration of the vibrating body 26 generated 
in the detection-axis (Y axis) direction when an angular velocity is not 
applied about the detected axis (Z axis) in a state in which the vibrating 
body 26 is vibrated in the vibration-axis (X axis) direction in the final 
step before shipment of the angular-velocity detection apparatus. 
Reference numeral 40 denotes an offset adjustment circuit. The offset 
adjustment circuit 40, formed of a phase adjustment circuit, an amplitude 
adjustment circuit and the like, transmits/receives signals between the 
offset adjustment circuit 40 and the driving circuit 36 and outputs 
signals to the correction driving circuit 39. Further, the offset 
adjustment circuit 40 is formed of adjustment means, such as a variable 
resistor and a variable capacitor. The offset adjustment circuit 40 
monitors the output signal Vo output from the angular-velocity signal 
conversion circuit 38 when an angular velocity is not applied about the 
detected axis (Z axis) in a state in which the vibrating body 26 is 
vibrated in the vibration-axis (X axis) direction in the final step and 
causes the adjustment means to set the phase difference and the amplitude 
of the correction signal so that the output signal Vo becomes zero. 
The angular-velocity detection apparatus according to this embodiment is 
formed of the angular-velocity detection element 21 and the 
above-described electrical circuit. The basic operation thereof is such 
that a driving signal Vd is applied from the driving circuit 36 to the 
vibration generation section 33, causing the vibrating body 26 to vibrate 
as indicated by the arrow a in the X-axis direction which is a vibration 
axis, and when an angular velocity .OMEGA. is applied about the Z axis 
which is a detected axis with the vibrating body 26 being vibrated in the 
vibration-axis direction, the vibrating body 26 is vibrated in the Y-axis 
direction which is a detection axis by a Coriolis force. Then, the 
vibration displacement of the vibrating body 26 in the detection-axis 
direction is detected as a change in the electrostatic capacitance between 
the electrode 28 for detection on the movable side and the electrode 31 
for detection on the fixation side, and this detection signal is output as 
an output signal Vo corresponding to the angular velocity .OMEGA. via the 
displacement-amount detection circuit 37 and the angular-velocity signal 
conversion circuit 38. 
Next, the vibration operation of the vibrating body 26 will be considered. 
Generally, when a displacement in two-axis directions is used, a model 
therefor can be shown as in FIG. 4. That is, the vibrating body 26 is 
supported in the X-axis direction, which is the vibration-axis direction, 
by two springs having a spring constant of k.sub.x /2 and is supported in 
the Y-axis direction, which is the detection-axis direction, by two 
springs having a spring constant of k.sub.y /2. 
Then, in this embodiment, as described earlier, the driving signal Vd which 
is a sine wave of a frequency f is fed to each vibration generation 
section 33, causing the vibrating body 26 to vibrate in the vibration-axis 
(X axis) direction. When an angular velocity .OMEGA. about the Z axis is 
applied in a state in which vibration in the form of a sine wave is 
performed, the vibrating body 26 is displaced in the detection-axis (Y 
axis) direction by a Coriolis force. 
However, as described in regard to the problems of the prior art, in spite 
of the fact that an angular velocity .OMEGA. about the Z axis is not 
applied to the vibrating body 26, the vibrating body 26 has been displaced 
in the Y-axis direction due to leakage vibration. When these operations 
are expressed by an equation of motion, the equation of motion in the 
X-axis direction can be represented by equation (3) below: 
EQU mx+cx x+kx x+2m.OMEGA.y=Fxexp(j.omega.t) (3) 
where cx is the attenuation coefficient in the X-axis direction, and Fx is 
the magnitude of the driving force in the X-axis direction. 
Also, the equation of motion in the Y-axis direction is as shown in 
equation (4) below: 
EQU my+cx y+ky y-2m.OMEGA.x=Fyexp [j(.omega.t+.phi.)] (4) 
where cy is the attenuation coefficient in the Y-axis direction, Fy is the 
magnitude of the driving force in the Y-axis direction, and .phi. is the 
phase difference between the driving force in the X-axis direction and the 
effective driving force in the Y-axis direction. 
Here, the term in which .OMEGA. in the above-described equations (3) and 
(4) is accumulated is a term in which an influence of the Coriolis force 
is received, and since there is no leakage of vibration energy if the 
vibrating body 26 is accurately vibrated in the X-axis direction, the 
magnitude Fy of the driving force in the Y-axis direction becomes zero. 
However, as described in regard to the prior art, since, in practice, Fy 
is a finite value due to the influence of leakage vibration, the S/N ratio 
of the output signal Vo is decreased and noise, such as temperature drift, 
is superposed. 
Next, the displacement Y of the vibrating body 26 in the Y-axis direction 
when corrective-vibration is applied from the corrective-vibration 
generation section 35 can be derived as equation (5) below on the basis of 
the above-described equations (3) and (4): 
EQU Y=.alpha.Fx.OMEGA. cos(.omega.t+.phi..sub.1)+.beta.Fy 
cos(.omega.t+.phi..sub.2)+.gamma..DELTA.F cos(.omega.t+.phi..sub.3)(5) 
Since .alpha., .beta. and .gamma. in the respective terms can be expressed 
by .omega. and the coefficients shown in equations (3) and (4), they are 
abbreviated as coefficients .alpha., .beta. and .gamma.. Further, 
.phi..sub.1 and .phi..sub.2 are expressed similarly as variables, and 
.phi..sub.3 is also dependent on the phase of the driving force in the 
Y-axis direction. Further, the displacement Y in equation (5) is such that 
the displacement y of the vibrating body 26 in the Y-axis direction and 
the error contained in the output signal Vo in the circuit are considered, 
and is shown for the output signal Vo and the angular velocity .OMEGA. 
output from the angular-velocity detection apparatus. 
Here, a description will be given of equation (5). The first term indicates 
the amount of displacement which the vibrating body 26 is displaced in the 
Y-axis direction by the Coriolis force, and if the other second and third 
terms are zero and there is only this first term, detection can be 
performed as the displacement Y with no error which opposes the angular 
velocity .OMEGA.. 
Next, the second term indicates the amount of vibration due to leakage 
caused by the parasitic capacitance of the substrate 22 and is an 
invariable amount determined by the mechanical construction and the 
construction of the electrical circuit of the angular-velocity detection 
element 21. 
Further, the third term indicates corrective-vibration of the vibrating 
body 26, which is generated by the corrective-vibration generation section 
35. A correction signal Vr applied to the corrective-vibration generation 
section 35 becomes as in equation (6) below on the basis of this third 
term: 
EQU Vr.varies..DELTA.F cos(.omega.t+.phi..sub.3) (6) 
Therefore, the correction signal Vr applied from the correction driving 
circuit 39 to the corrective-vibration generation section 35 has the same 
frequency f as that of the driving signal Vd and becomes such that 
.DELTA.F and .phi..sub.3 can be adjusted, that is, the amplitude and the 
phase difference can be adjusted. As a result, by adjusting the correction 
signal Vr, the second term and the third term in equation (5) can be 
cancelled in respect of each other, and equation (5) indicates a 
displacement only in the detection-axis direction by the Coriolis force of 
the first term. 
Thus, in the angular-velocity detection apparatus in accordance with this 
embodiment, in the angular-velocity detection element 21 which constitutes 
the angular-velocity detection apparatus, by applying to each 
corrective-vibration generation section 35 a correction signal Vr 
different from the driving signal Vd applied to each vibration generation 
section 33, the vibrating body 26 is made to generate corrective-vibration 
in the detection-axis direction regardless of the presence or absence of 
the angular velocity .OMEGA. about the Z axis. Therefore, it is possible 
to suppress leakage vibration which occurs in the detection-axis direction 
of the vibrating body 26 by corrective-vibration. 
Further, in the adjustment of the correction signal Vr, in the final step 
of the angular-velocity detection apparatus, the amplitude of the 
correction signal Vr and the phase difference are set so as to make the 
output signal Vo zero by adjusting the adjustment means of the offset 
adjustment circuit while the leakage vibration of the vibrating body 26 
when the angular velocity .OMEGA. is not applied about the detected axis 
is monitored by the output signal Vo from the angular-velocity signal 
conversion circuit 38 in a state in which the driving signal Vd is applied 
to each vibration generation section 33 from the driving circuit 36 in 
order to cause the vibrating body 26 to be vibrated in the vibration 
direction. 
As a result, the leakage vibration of the vibrating body 26 can be 
cancelled by the corrective-vibration applied to the vibrating body 26 
from each corrective-vibration generation section 35, the leakage 
vibration can be suppressed, and when the angular velocity .OMEGA. is not 
applied, the vibrating body 26 can be vibrated only in the vibration-axis 
direction. Further, since the adjustment of the corrective-vibration which 
suppresses the leakage vibration which occurs in the vibrating body 26 is 
set on the basis of the output signal Vo output from the angular-velocity 
signal conversion circuit 38, even the amount of error which occurs from 
the circuit added to the angular-velocity detection element 21 can be 
eliminated. As a result, when the angular velocity .OMEGA. about the 
detected axis (Z axis) is applied, it is possible to cause the vibrating 
body 26 to vibrate in the detection-axis direction by only the Coriolis 
force caused by this angular velocity .OMEGA., making it possible to 
accurately detect the angular velocity .OMEGA. and to increase detection 
sensitivity. 
Further, by forming the correction signal Vr applied to each of the 
corrective-vibration generation sections 35 into a sine wave which has the 
same frequency as that of the driving signal Vd and which is different in 
its amplitude and phase difference therefrom, leakage vibration can be 
surely cancelled, as shown in equation (5). 
Thus, in the angular-velocity detection apparatus in accordance with this 
embodiment, since leakage vibration which occurs in the vibrating body 26 
is cancelled by applying a correction signal Vr to the 
corrective-vibration generation section 35 in order to cause the vibrating 
body 26 to generate corrective-vibration, it is possible to accurately 
detect the angular velocity .OMEGA. about the detected axis and to 
increase the reliability of the apparatus. Furthermore, since 
corrective-vibration is set for each angular-velocity detection apparatus, 
it is possible to prevent variations due to manufacturing errors or the 
like for each angular-velocity detection element 21 and to improve the 
yield. 
Further, in this embodiment, since leakage vibration which occurs in the 
vibrating body 26 is removed when the vibrating body 26 is in a vibrating 
state, it is possible to prevent a displacement of the vibrating body 26 
in the detection-axis direction due to leakage vibration of the vibrating 
body 26 from being detected by each displacement detection section 34 and 
possible to obviate an external circuit for correcting the output signal 
Vo. 
Next, a second embodiment of the present invention is shown in FIGS. 5 and 
6. The feature of this embodiment is that a self-diagnostic function is 
provided which causes a vibrating body to be displaced in the 
detection-axis direction by inputting a predetermined correction signal 
when an angular velocity is not applied and which determines whether or 
not the vibrating body 26 is operating normally on the basis of the 
relationship at this time between the correction signal and the 
displacement. 
Components in the second embodiment which are the same as those of the 
above-described first embodiment are given the same reference numerals and 
therefore, a description thereof has been omitted. 
In FIG. 5, reference numeral 41 denotes a pseudo-signal generation circuit 
used for self-diagnoses, with the output side of the pseudo-signal 
generation circuit 41 being connected to the driving circuit 36, the 
angular-velocity signal conversion circuit 38, the offset adjustment 
circuit 40 and the correction driving circuit 39 and a self-diagnostic 
signal Vt being input to the input side from an external control unit (not 
shown). When the self-diagnostic signal Vt is input to the pseudo-signal 
generation circuit 41, a signal is input from the pseudo-signal generation 
circuit 41 to the correction driving circuit 39, and a pseudo signal Vf 
which is a predetermined correction signal of a DC voltage is fed from the 
correction driving circuit 39 to the corrective-vibration generation 
section 35. 
Reference numeral 42 denotes an apparatus determination circuit, with the 
angular-velocity signal conversion circuit 38 being connected to the input 
side of the apparatus determination circuit 42 and a display unit 43 being 
connected to the output side. The apparatus determination circuit 42 is 
formed of a subtraction circuit, a comparator circuit and the like, which 
are not shown. An output signal VOf corresponding to the pseudo signal Vf 
is set in the subtraction circuit, and a determination value a for 
determining whether or not the operation of the vibrating body 26 is 
normal is set as a voltage value in the comparator circuit. 
Next, the operation of the apparatus determination circuit 42 will be 
described with reference to the flowchart of a self-diagnoses process in 
FIG. 6. 
Initially, in step 1, the displacement of the vibrating body 26 in the 
detection-axis direction is read as the output signal Vo into the 
apparatus determination circuit 42 via the displacement-amount detection 
circuit 37 and the angular-velocity signal conversion circuit 38. In step 
2, a check is made to determine if this output signal Vo is a signal 
corresponding to the displacement caused by the angular velocity .OMEGA. 
about the Z axis. In the case of "YES", since the angular velocity .OMEGA. 
has been applied, the process of steps 1 and 2 is repeated until a state 
is reached in which the angular velocity .OMEGA. is not applied. When it 
is determined to be "NO" in step 2, the process proceeds to step 3. 
In step 3, a self-diagnostic signal Vt is input to the pseudo-signal 
generation circuit 41 from the external control unit, and a signal is 
input from the pseudo-signal generation circuit 41 to the driving circuit 
36, the angular-velocity signal conversion circuit 38, the offset 
adjustment circuit 40 and the correction driving circuit 39. Then, the 
pseudo signal Vf is input from the correction driving circuit 39 to the 
corrective-vibration generation section 35, and the vibrating body 26 is 
displaced in the detection-axis (Y axis) direction. 
In the subsequent step 4, the displacement of the vibrating body 26 in the 
detection-axis direction is output as the output signal Vo to the 
apparatus determination circuit 42 via the displacement-amount detection 
circuit 37 and the angular-velocity signal conversion circuit 38. 
In step 5, a subtraction value .DELTA.V is obtained by the subtraction 
circuit in the apparatus determination circuit 42 by subtracting a 
predetermined output signal Vof corresponding to the magnitude of the 
preset pseudo signal Vf from the output signal Vo output from the 
angular-velocity signal conversion circuit 38. 
Further, in step 6, whether the subtraction value .DELTA.V computed in step 
5 is within a predetermined range .alpha. is determined by the comparator 
circuit in the apparatus determination circuit 42. When it is determined 
to be "YES" in this step 6, the process proceeds to step 7 where, assuming 
that the vibrating body 26 is operating normally, "normal" is displayed on 
the display unit 43. 
On the other hand, when it is determined to be "NO" in step 6, the process 
proceeds to step 8 where, assuming that the operation of the vibrating 
body 26 is not normal, "abnormal" is displayed on the display unit 43. 
As described above, in this embodiment, when an angular velocity .OMEGA. is 
not applied about the Z axis, the pseudo signal Vf is applied to the 
corrective-vibration generation section 35, causing the vibrating body 26 
to be displaced in the Y-axis direction, thus making the same state as 
when a Coriolis force is generated. Then, it is possible to diagnose the 
abnormality of the angular-velocity detection element 21 with respect to 
the displacement of the vibrating body 26. 
Furthermore, in the self-diagnoses in accordance with this embodiment, a 
determination in steps 1 and 2 of the state in which the angular velocity 
.OMEGA. is not applied may be made by the control unit of, for example, a 
navigation apparatus after the angular-velocity detection apparatus is 
connected to the navigation apparatus. In this case, a self-diagnosis can 
even be performed automatically in accordance with the self-diagnostic 
signal Vt, making it possible to considerably improve the reliability of 
the angular-velocity detection apparatus. 
Thus, according to this embodiment, since the corrective-vibration 
generation section 35 for causing the vibrating body 26 to be displaced in 
the detection-axis direction is provided, it is possible to cause the 
vibrating body 26 to be displaced in the detection-axis direction by the 
pseudo signal Vf and to determine the abnormality of the angular-velocity 
detection element 21. 
Although the angular-velocity detection element 21 of each of the 
above-described embodiments is provided with the corrective-vibration 
generation sections 35 and 35 on the front and back of the vibrating body 
26 and the displacement detection sections 34 and 34 on the right and left 
of the vibrating body 26 as shown in FIG. 2, the present invention is not 
limited to this example, and the displacement detection section may be 
formed of the electrode 29 for corrective vibration on the movable side 
and the electrode 32 for corrective-vibration on the fixation side, which 
constitute each corrective-vibration generation section 35 positioned at 
the front and back of the vibrating body 26, and the corrective-vibration 
generation section may be formed of the electrode 28 for detection on the 
movable side and the electrode 31 for detection on the fixation side, 
which constitute each displacement detection section 34 positioned at the 
right and left of the vibrating body 26. 
Further, although in each of the above-described embodiments the vibration 
axis and the detection axis are made the X and Y axes, which are two axes 
in the horizontal direction of the vibrating body 26, the present 
invention is not limited to this example, and the vibration axis may be 
made the X axis, the detected axis may be made the Y axis, and the 
detection axis may be made the Z axis, and further, the vibration axis may 
be made the Z axis, the detected axis may be made the Y axis, and the 
detection axis may be made the X axis. In this case, the displacement 
detection means, the corrective-vibration generation means and/or the 
vibration generation means may be provided between the vibrating body 26 
and the substrate 22. 
Although the present invention has been described in relation to particular 
embodiments thereof, many other variations and modifications and other 
uses will become apparent to those skilled in the art. It is preferred, 
therefore, that the present invention be limited not by the specific 
disclosure herein, but only by the appended claims.