JP3529993B2 - Piezoelectric element - Google Patents

Description

Detailed Description of the Invention

[0001]

The present invention relates to the pressure Denmoto element, an actuator, filter, display, trans, microphones, sounding bodies (speakers or the like), various vibrators, resonators,
Oscillator, a discriminator, and further relates unimorph pressure Denmoto probe used for a gyro, or sensor. The element referred to here converts electrical energy into mechanical energy, that is, mechanical displacement,
In addition to an element that converts force or vibration, an element that performs the opposite conversion is included.

[0002]

2. Description of the Related Art In recent years, in the fields of optics and precision processing, a displacement element for adjusting the optical path length and position on the order of submicrons and a detection element for detecting a minute displacement as an electrical change have been desired. Is coming.

In response to this, an actuator that utilizes the manifestation of displacement due to the inverse piezoelectric effect that occurs when an electric field is applied to a piezoelectric material such as a ferroelectric substance, and a sensor that utilizes the opposite phenomenon (piezoelectric effect) pressure electrostatic used in equal
The development of the element has been developed.

[0004] Among them, in the speaker or the like, as such pressure Denmoto child structure, unimorph type which is conventionally known are preferably employed.

[0005] Therefore, even in the present applicant, above, in JP-A-3-128681 and JP 5-49270 Patent Publication, ceramic pressure film to be suitably used for various applications A mold element was proposed.

[0006] pressure film type element according to the proposal example, FIG. 30
As shown in, at least one thin wall portion (that is, the vibration portion 102) is formed by integrally providing the thin vibration portion 102 so as to cover at least one window portion (space) 100. A ceramic substrate 104,
On the outer surface of the vibrating portion 102 of the ceramic substrate 104, an integrally laminated structure by a film forming method pressure electrostatic operation pivot portion 112 consisting of the lower electrode 106 and the pressure conductive layer 108 and the upper electrode 110 Have. In addition, in the ceramic substrate 104, a portion other than the void 100 functions as a fixed portion 114 that supports the vibrating portion 102.

[0007] pressure Denmoto element according to the proposed example, small and inexpensive, with an electro-mechanical conversion element with high reliability, a large displacement is obtained at a low driving voltage and response speed, and, It has an excellent feature that it can generate a large amount of force, and is useful as a constituent member such as an actuator, a filter, a display, a sensor and the like.

[0008]

[SUMMARY OF THE INVENTION Incidentally, the pressure Denmoto In <br/> child, pressure conductive layer 108 the structure of pressure conductive work moving unit 112
An upper electrode 110 and a lower electrode 106 are formed in the so-called sandwich structure. If this <br/> pressure electrostatic operation motion section 112 of the sandwich structure, viewed bending displacement characteristic of the pressure Denmoto element body of the vibration portion 102 and the fixing portion 114, FIG. 31B
As shown in FIG. 3, the positive and negative electric field directions are symmetrical with respect to the reference electric field point (electric field E = 0 point).

[0009] Here, the bending displacement, the case where pressure Denmoto child body is displaced in a convex shape with respect to one direction (the direction in which the upper electrode 110 formed on the pressure conductive layer 108 faces the free space) forward , The case of displacing in a concave shape is the negative direction.

[0010] The displacement characteristic, a predetermined voltage is applied between the upper electrode 110 and lower electrode 106, after the pressure conductive layer 108 was polarized, the electric field applied to the pressure Denmoto child, for example, + 3E
→ −3E → + 3E, so that the upper electrode 110 has an electric field of
And those viewed displacement of pressure Denmoto child body when continuously changing the voltage applied between the lower electrode 106.

[0011] That is, with respect to pressure Denmoto child, first, after the polarization treatment the pressure conductive layer 108 by applying an electric field for polarization in the positive direction (e.g., + 5E), the voltage application between the upper electrode 110 and lower electrode 106 Is stopped and the voltage is unloaded. And
Together with the measurement start, frequency 1Hz the pressure Denmoto child, the peak value ±
A sine wave of 3E (see FIG. 31A) is applied, and the displacement amount at each point (point A to point D) at that time is continuously measured using a laser displacement meter. The measurement result at that time is the electric field −
What is plotted on the bending displacement graph is the characteristic diagram of FIG. 31B. As shown by the arrow in FIG. 31B, the displacement amount of the bending displacement continuously changes as the electric field continuously increases and decreases.

[0012] Specifically, assuming that starts the measurement from the electric field + 3E, as shown in FIG. 32A, first, the pressure Denmoto child, since the electric field in the same direction as the polarization direction is applied, pressure electrostatic The layer 108 extends in the direction between the upper electrode 110 and the lower electrode 106, and contracts in the direction parallel to the upper electrode 110 and the lower electrode 106. As a result, the overall pressure Denmoto element is displaced in the negative direction as 0.9Derutawai.

After that, when the electric field is changed from + 3E to -0.5E, the displacement amount gradually decreases. When the electric field is in the negative direction, as shown in FIG. 32B, the electric field is applied in a direction opposite to the direction of polarization, pressure conductive layer 108, the elongation occurs in a direction parallel to the upper electrode 110 and lower electrode 106, the displacement Changes in the positive direction.

Next, when the electric field is changed from -0.5E to -3E, the direction of polarization gradually begins to reverse. That is, the direction of the electric field and the direction of polarization begin to be aligned. Figure 31
It is considered that the polarization is almost completely inverted at point c among point B → point c → point C of B. The reason is that no hysteresis is observed between the points c and C.

[0015] Then, As shown in FIG. 33A, by the orientation and the direction of polarization of the electric field are aligned, pressure conductive layer 108
Changes from a state of extending horizontally to a state of contracting. When the electric field reaches −3E, the amount of displacement is almost the same as the amount of displacement (0.9Δy) at the start of measurement.

[0016] That is, if the polarization direction and electric field direction coincides, pressure conductive layer 108, will be contracted in a direction parallel to electrodes 110 and 106 (extending between the electrodes 110 and 106 direction), which points A and The state of C corresponds. Also, if the polarization direction and electric field direction is opposite, pressure conductive layer 108,
The electrodes 110 and 106 extend in the parallel direction (electrode 110
And 106). This corresponds to the states of points B and D. 1E = approximately 1.7 kV / m
m, 1Δy = about 1.6 μm.

Thereafter, when the electric field is changed from -3E to + 0.5E, the displacement amount gradually decreases, and when the electric field is in the positive direction, as shown in FIG. 33B, the electric field is generated in the direction opposite to the polarization direction. since it takes, pressure conductive layer 108, the upper electrode 11
Elongation occurs in the direction parallel to 0 and the lower electrode 106, and the displacement changes in the positive direction.

[0018] Then, + 0.5E → + and go by changing the electric field to 3E, beginning reversed gradually polarization direction, by the orientation and polarization of the direction of the electric field are aligned, pressure conductive layer 1
08 changes from a state of extending in the horizontal direction to a state of contracting.

[0019] Thus, in the conventional pressure Denmoto child,
Since the bending displacement characteristic is symmetrical about the reference electric field point (electric field E = 0) in the positive direction and the negative direction of the electric field, the relative displacement amount in the voltage unloaded state and the voltage applied state, The amount of relative displacement is small when an electric field in the opposite direction is applied, and for example, the amount of displacement when used as an actuator due to the inverse piezoelectric effect may become small, or the sensitivity when used as a sensor due to the piezoelectric effect may become low. .

[0020] Therefore, when using a pressure Denmoto child as an actuator, there is a possibility that the control becomes difficult,
When using a pressure Denmoto child as a sensor, it is necessary to connect the high price of an amplifier gain is also considered large noise suppression in a subsequent stage.

[0021] This problem is particularly use a number of pressure Denmoto child body and Kaku圧Denmoto child electronic devices that need to keep the quality constant of the body, for example, a number of pressure Denmoto child corresponding to the pixels This may be extremely disadvantageous when manufacturing a display device configured by arranging main bodies.

The present invention has been made in consideration of the above problems, and the relative displacement amount in a voltage unloaded state and a voltage applied state, and the relative displacement amount in a state in which electric fields in opposite directions are applied are shown. greatly enlarged, ease of control when using as an actuator, and an object thereof is to provide a pressure Denmoto child that can realize improvement of sensitivity when used as a sensor.

[0023]

Pressure Denmoto child according to the present invention SUMMARY OF THE INVENTION The first aspect, pressure electrodeposition having a pressure conductive layer, and a pair of electrodes formed only on one main surface of the piezoelectric layer a work moving unit, the pressure conductive
A vibrating section for supporting the pressure conductive work pivot portion in contact with the other major surface of the layer, the fixed part and the pressure Denmoto element provided with the unimorph pressure Denmoto element body having the vibratable supporting said vibrating section In, the piezoelectric layer is provided at least between the pair of electrodes.
In the surface portion on the one main surface side of the piezoelectric layer, the one main surface
Is polarized in a direction parallel to the
The main part of the piezoelectric layer between the pair of electrodes is
Of the electric field at which the polarization in the surface portion on the surface side begins to reverse
Wherein by more than double of the applied electric field pressure Denmoto terminal body of the electric field - especially the bending displacement characteristic is asymmetrical about a reference electric field point
To collect.

[0024] The bending displacement characteristic, after polarization treatment the pressure conductive layer by applying a voltage for polarization between the pair of electrodes in the pressure conductive work moving unit, the electric field applied to the pressure Denmoto child is alternately changed as to, which viewed bending displacement of pressure Denmoto child body when continuously changing the voltage applied between the pair of electrodes, and the flexural displacement of the case, is pressure Denmoto terminal body the case of one-way displacement in a convex shape with respect to (a pair formed on pressure conductive layer electrode direction facing the free space) forward, and a negative direction when displaced in a concave. Here, the the predetermined electric field refers to a field polarization direction of the portion close to the one main surface (surface) of the pressure conductive layer is reversed by the application of the reverse electric field.

[0025] Specifically, for example, applying a predetermined voltage, for example, in the positive direction between the pair of electrodes to polarization treatment the pressure conductive layer, the electric field in the positive direction is generated in the surface direction in the main surface of the pressure conductive layer . The intensity of the electric field generated in the pressure conductive layer, wherein one main surface is the largest, and gradually decreases in the depth direction. Pressure conductive layer, said by the occurrence of the positive direction of the electric field is polarized in the same direction as the electric field. After that, for example, the voltage application between the pair of electrodes is stopped and the voltage is unloaded.

[0026] Then, as the electric field applied to the pressure Denmoto child varies alternately, continuously changing the voltage applied between the pair of electrodes. In this case, for example, in a stage in which the electric field in the same direction as the direction (e.g., positive direction) of the electric field which occurs at the time of the polarization process is occurring, the direction of the polarization direction and the electric field is matched in the pressure conductive layer, a pressure conductive layer since the electric field is applied strongly near the surface, pressure conductive layer will be extending in the horizontal direction. Thus, pressure Denmoto child body is considered to be displaced in either direction in one direction and the other direction.

[0027] Then, after changing the voltage applied between the pair of electrodes, at the stage of the electric field in the direction opposite to the direction of the electric field during the polarization treatment in pressure Denmoto child has occurred, the following action Will be done.

First, when the electric field is weak,Electric layerPolarization of
And the direction of the electric field are opposite to each other,Electric layer
Will contract in the horizontal direction. By this, pressureElectric element
The child body is bent and displaced in the other direction. Then the electric field is strong
When it comes to pressureElectric layerThe polarization of the surface part of the
PressureElectric layerIn the vicinity of the surface of the
PressureElectric layerIn the deep part of, the direction of polarization and the direction of electric field
The phenomenon of being reversed occurs. That is, pressureElectric layerAt
Since there are two types of polarization, a pseudo bimorph
F-shaped pressureElectric elementIt will function as a child.

[0029] and a result close to the one main surface of the pressure conductive layer portion,
Strain direction at a portion close to the vibrating section is reversed to each other, the whole was convex displaced in one direction (direction in which the pair of electrodes formed on the pressure conductive layer facing the free space) as its displacement, said It becomes very large by the pseudo bimorph effect.

In particular, in the present invention, since the displacement characteristic is asymmetrical in the positive and negative directions of the electric field with the reference electric field point as the center, for example, at two peak values of the electric field that periodically changes. A difference occurs in each bending displacement amount. Thus, and the relative displacement amount at the no-voltage-loaded state and the voltage application state, the greater the relative displacement amount at the state of applying a reverse electric field from each other, facilitating the control of the case of using the pressure Denmoto element as an actuator And improved sensitivity when used as a sensor.

[0031] When utilizing the pressure Denmoto child to the actuator or sensor, in one principal surface portion of the piezoelectric layer
When the electric field where the polarization starts to be reversed is defined as the predetermined electric field,
Referenced to the reference electric field point, the absolute value of the displacement amount when the direction is respectively applied four times more field two of the predetermined electric field different in the same A, when is B, the A ≧ 1.5B relationship (Invention according to claim 2) is preferable.
This relationship, as the bending displacement characteristic, the reference electric field point can be obtained asymmetric become characteristic to the center, increase the sensitivity of the case of using the ease of control when using pressure Denmoto child as an actuator, as a sensor Can be reliably realized.

Next, pressure Denmoto <br/> element according to the present invention according to claim 3, pressure has a pressure conductive layer, and a pair of electrodes formed only on one main surface of the piezoelectric layer a conductive work moving unit, a vibrating section for supporting the pressure conductive work pivot portion in contact with the other main surface of the pressure conductive layer, pressure Denmoto unimorph having a fixing portion vibratably supporting said vibrating section A child body, wherein the piezoelectric layer is at least front
A surface portion on the one main surface side of the piezoelectric layer between the pair of electrodes
Minute is polarized in a direction parallel to the one main surface, and
該分poles are those containing an inverted, distance x (1μm ≦ x ≦ 200μm) between the pair of electrodes, when the thickness of the pressure conductive layer was y (1μm ≦ y ≦ 100μm) , y = ax
It has a relationship that, and a 1/10 ≦ a ≦ 100
Is characterized by .

[0033] In this case, the displacement characteristics of the pressure Denmoto terminal body by applying an electric field between the pair of electrodes, the displacement characteristic as shown in the invention described in claim 1, that is, the asymmetrical about a reference electric field point The characteristics can be obtained. Therefore, even in the pressure Denmoto element according to the present invention of claim 3, wherein, as in the claim 1, wherein the pressure Denmoto child, ease of control when using pressure Denmoto child as an actuator, a sensor It is possible to improve the sensitivity when used as.

In the invention according to any one of claims 1 to 3, the vibrating portion and the fixed portion are integrally formed of ceramics, and a void is formed at a portion corresponding to the vibrating portion. Te, if so the vibrating portion is thin (the invention described in claim 4), becomes a fixed portion can be manufactured easily vibrating part, to intend the production cost of the pressure Denmoto child Will be advantageous.

Further, since the shape of the vibrating portion of the fixing portion and the thin thick is formed by providing a hollow space in the base body constituted by a ceramic, the vibration unit is sensitive to the displacement of the pressure conductive layer However, it is possible to provide a vibrating section having a high trackability with respect to changes in the voltage signal. Further, since the rigidity of the boundary between the vibrating part and the fixed part is sufficiently secured, the damage due to the fatigue of the boundary due to the vibration of the vibrating part is less likely to occur.

In the above structure, it is preferable that 1/5 ≦ a ≦ 10 (the invention according to claim 5), and 1/2 ≦ a
≦ 5 and 1 μm ≦ x ≦ 60 μm, 1 μm ≦ y
It is more preferable that ≦ 40 μm (the invention according to claim 6).

Further, in the above structure, when the thickness of the vibrating portion is z (1 μm ≦ z ≦ 50 μm), there is a relation of y = bz and 1/5 ≦ b ≦ 10. 7
It is possible to increase the amount of flexural displacement.

In the above structure, it is preferable that 1 / 3≤b≤5 (the invention of claim 8), and 1 / 3≤b≤.
5 and 1 μm ≦ y ≦ 40 μm, 1 μm ≦ z ≦
20 μm is more preferable (the invention of claim 9).

Further, in the above construction, if the cross-sectional shape in the shortest dimension passing through the center of the vibrating portion satisfies the following condition under no voltage load (claim 10):
The invention described), the displacement characteristics of the <br/> pressure Denmoto terminal body by applying an electric field between the pair of electrodes, becomes asymmetric about the reference electric field point, as with pressure Denmoto terminal of claim 1, wherein , it is possible to realize improvement of sensitivity of the case of using the pressure Denmoto <br/> child ease of control when used as an actuator, as a sensor.

[0040] Moreover, it is possible to achieve an improvement in yield when be always performed a large bending displacement in the first direction with respect to the manufactured pressure collector Body can, and for use in various types of electronic equipment.

[0041] (1) than the outermost local minimum point of one adjacent to the fixed portion and the other of the reference line formed by connecting the outermost local minimum point, at least a portion of the upper surface in the vicinity of the center portion of the pressure conductive layer Should project in the direction opposite to the vibrating part.

(2) If the outermost minimum point does not exist,
On the upper surface of the vibrating portion along the shortest dimension, a point corresponding to a boundary point with the fixed portion is set as an outermost minimum point.

(3) When the boundary portion of the vibrating portion with the fixed portion is set to 0 point and the shortest dimension length of the vibrating portion is set to 100, the outermost local minimum point is the shortest in the vibrating portion from the 0 point. If it is not within the range of 40% of the dimension length, the point corresponding to the boundary point with the fixed portion on the upper surface of the vibrating portion along the shortest dimension should be the outermost minimum point.

[0044] Particularly, in the invention of claim 10 wherein, prior to
The shortest dimension passing through the center of the serial oscillating section m, in the (1)
When the amount of protrusion is t, m / 1000 ≦ t ≦ m
More preferably, it is / 10 (the invention according to claim 11).

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of implementation of the pressure Denmoto element according to the present invention (hereinafter, simply referred to as pressure Denmoto element according to the embodiment) described with reference to FIGS. 1 to 19 further, the applied example to a display device pressure Denmoto element according to the present embodiment (hereinafter referred to as a display device according to the embodiment) to FIGS. 20 2
This will be described with reference to FIG.

Firstly, pressure Denmoto element according to the present embodiment, as shown in FIG. 1, for example, a substrate 10 which is composed of ceramic, the actuator unit 12 at a predetermined position of the base member 10 is disposed Has been done. The base body 10 is a surface (one surface) where one main surface is continuous, and the other main surface is provided with a recess 14 at a position corresponding to the actuator section 12.

That is, in the base body 10, the portion where the recess 14 is formed is thin, and the other portions are thick. The thin portion has a structure that is susceptible to vibration against external stress and functions as the vibrating portion 16, and the portion other than the concave portion 14 is made thick and functions as the fixing portion 18 that supports the vibrating portion 16. It has become. Although not shown, a wiring substrate is attached to the other main surface side of the base body 10. Further, the base 10 may be integrally fired or may be attached later.

[0048] The actuator unit 12, as shown in FIG. 1, in addition of the vibrating portion 16 and the fixed portion 18, a pressure conductive layer 20 which is directly formed on the vibrating section 16, the upper surface of the piezoelectric layer 20 Actuator part main body 24 having a pair of electrodes (one electrode 22a and the other electrode 22b) formed in the
Is configured.

Here, the shape of each member will be described with reference to FIGS. First, as shown in FIG. 3, the peripheral surface shape of the recess 14 formed in the other main surface, i.e., the planar shape of the vibration unit 16 is for example a circular (see broken lines) of the base body 10, the planar shape of the pressure conductive layer 20 The outer peripheral shape (see the solid line) formed by the one-dot chain line and the pair of electrodes 22a and 22b is also circular. In this case, the size of the vibrating portion 16 is the largest, then the outer peripheral shape of the pair of electrodes 22a and 22b, the planar shape of the pressure conductive layer 20 is smallest set. The outer peripheral shape of the pair of electrodes 22a and 22b may be set to be the largest.

The pair of electrodes formed on the pressure conductive layer 20 22
The planar shapes of a and 22b are, for example, as shown in FIG.
The pair of electrodes 22a and 22b are formed in a spiral shape which is parallel to each other and is separated from each other by several turns.
The number of turns of this spiral is actually 5 or more, but in the example of FIG. 4, it is described as 3 turns in order to avoid complication of the drawing.

The plane shape of the pair of electrodes 22a and 22b may be the shape shown in FIG. 5 in addition to the spiral shape shown in FIG. Specifically, the pair of electrodes 2
2a and 22b are both a shape having branches 30 and 32 formed by a number branching from the stem 26 and 28 extending toward the center of the pressure conductive layer 20 and the stem portion 26 and 28, and a pair of electrodes 22a and 22b may have a shape in which they are spaced apart from each other and arranged in a complementary shape (hereinafter, referred to as a multi-branched shape for convenience).

[0052] In the above example, the planar shape of the vibrating section 16, pressure conductive
The case where the planar shape of the layer 20 and the outer peripheral shape formed by the pair of electrodes 22a and 22b are circular is shown. However, in addition, an elliptical shape (see FIGS. 22 and 23) and an elliptical shape (see FIG. 24) May be Also, together with the rectangular shape of the planar shape of the planar shape and pressure conductive layer 20 of the vibrating section 16,
It corners may be rounded shape of the corner (see FIG. 25), and both polygonal planar shape of the planar shape and pressure conductive layer 20 of the vibrating portion 16 (octagonal in the example of FIG. 26), each top The corners may be rounded.

[0053] The shape of the vibrating section 16, the outer peripheral shape shaped planar shape of the pressure conductive layer 20, by a pair of electrodes 22a and 22b may be a combination of circles and ellipses may be a combination of rectangular and oval It is not particularly limited.

[0054] The planar shape of the pressure conductive layer 20, as shown in FIGS. 6 and 7, it is preferably employed that a ring-shaped (hollow). Also in this case, as shown in FIGS. 9A to 9C, various shapes such as a circle, an ellipse, and a rectangle can be given as the outer peripheral shape. 8, the planar shape of the pressure conductive layer 20 and the annular shows an example of a multi-vessel shape a pair of electrodes 22a and 22b.

[0055] By the planar shape of the pressure conductive layer 20 and the ring-shaped, it is not necessary to form the electrode in the hollow portion,
The electrostatic capacitance can be reduced without reducing the displacement amount.

Next, will be described with reference to FIGS. 10 to 13, the operation principle of the pressure Denmoto element according to the present embodiment.

Firstly, pressure Denmoto element according to the present embodiment, as shown in FIG. 10B, the pair of electrodes 22a and 22b
The bending displacement characteristic of the actuator portion 12 due to the applied electric field between them becomes asymmetrical about the reference electric field point (point where electric field E = 0).

[0058] The bending displacement characteristic, a predetermined voltage is applied between the pair of electrodes 22a and 22b of the main actuator element 24, after the pressure conductive layer 20 is polarized continuously changes the voltage applied to the actuator portion 12 The figure shows the bending displacement of the actuator portion 12 when the actuator portion 12 is moved.
The The bending displacement of the case, as shown in FIG. 2, the actuator portion 12 is in a convex shape with respect to one direction (the direction in which the pair of electrodes 22a and 22b formed on the pressure conductive layer 20 faces the free space) The case of bending displacement is the positive direction, and the case of concave bending displacement is the negative direction.

A specific example of the measurement of the bending displacement characteristic will be described. First, as shown in FIG. 11A,
For example, a pair of electrodes pressure conductive layer 20 to the polarization treatment 22
For example, if a predetermined voltage is applied between a and 22b in the positive direction,
In the plane direction in the main surface of the pressure conductive layer 20 positive direction of the electric field (e.g. electric field indicated by + 5E in FIG. 10B) is generated. Here, 1E = about 2.5 kV / mm.

[0060] intensity of the electric field generated in the pressure conductive layer 20, the one main surface is the largest, and gradually decreases in the depth direction. Therefore, the polarization in the deep portion is difficult to proceed, but the polarization can be advanced in the depth direction by applying a sufficient electric field, a sufficient time, and appropriate heat.

Range of use of electric field used as actuator (for example, range of + 3E to -3E in FIG. 10B)
By applying an electric field (+ 5E) exceeding the value of, for example, for 7 hours at an appropriate temperature, polarization is performed in the same direction as the applied electric field.

After that, as shown in FIG. 11B, the voltage application between the pair of electrodes is stopped and the voltage is unloaded. Then, the start of measurement, frequency 1 Hz, sine wave peak values ± 3E (see FIG. 10A) is applied to the pressure Denmoto child, successively a displacement amount at each point (point A~ point D) at that time Measure with a laser displacement meter. The measurement result at that time is the electric field −
What is plotted in the bending displacement graph is the characteristic diagram of FIG. 10B. As shown by the arrow in FIG. 10B, the displacement amount of the bending displacement continuously changes with some hysteresis due to continuous increase and decrease of the electric field.

[0063] Specifically, assuming that starts when an electric field + 3E showing the measurement at point A, first, in the point A, as shown in FIG. 12A, and the directions of the polarization direction and the electric field in the pressure conductive layer 20 matching, since the electric field is applied strongly near the surface of the pressure conductive layer 20, the pressure conductive layer 20 will be extending in the horizontal direction, the actuator unit 12, in one direction (pressure conductive layer 2
The pair of electrodes 22a and 22b formed on the surface 0 are bent and displaced by about 0.8Δy in the direction facing the free space (FIG. 1).
0B). Note that 1Δy = about 1.6 μm.

[0064] Then, after changing the voltage applied between the pair of electrodes 22a and 22b, at the stage that the direction of the electric field of direction opposite to the electric field during the polarization treatment in pressure Denmoto child has occurred, the following Such an operation will be performed.

First, the electric field is weak, for example, point B (-0.6
In the stage of E), as shown in FIG. 12B, the direction of the direction and the electric field of polarization of pressure conductive layer 20 are reversed to each other, pressure electrostatic
The layer 20 will shrink in the horizontal direction. by this,
The actuator portion 12 is bent and displaced approximately -0.3Δy in the other direction (direction toward the vibrating portion 16 from the pressure conductive layer 20). Further, this step is a step of polarization at the surface portion of the pressure conductive layer 20 begins to inversion, thus, it can be defined electric field (-0.6E) at this point B with a predetermined field.

[0066] Then, the negative direction of the electric field becomes strong, as shown in FIG. 13A, the polarization inversion proceeds at the surface portion of the pressure conductive layer 20, the direction of polarization near the surface of the pressure conductive layer 20 and the field directions match, the phenomenon that the direction of the direction and the electric field of polarization is reversed occurs at deep portion of the pressure conductive layer 20. That is, in the pressure conductive layer 20 causes the two polarization exists, will function as a pseudo-bimorph pressure Denmoto child. Particularly, when the electric field is −3E, the displacement amount of the actuator portion 12 becomes extremely large due to the pseudo bimorphic action, and in the example of FIG. 10B, displacement = about 2.6Δy. ing.

Next, when the electric field shifts from the negative direction to the positive direction and the electric field is weak, for example, at the stage of point D (+ 0.6E), FIG.
As shown in B, in the vicinity of the surface of the pressure conductive layer 20 is the direction the reverse direction and the electric field polarization in the deep portion of the pressure conductive layer 20 and the direction of the direction and the electric field of polarization coincide, pressure conductive layer 20 is
The area near the surface shrinks horizontally, and the deep part extends horizontally.

As a result, the actuator section 12
Bent and displaced approximately -1.0Δy in the other direction (direction toward the vibrating portion 16 from the pressure conductive layer 20). At this stage,
This is the stage where the polarization in the surface portion of the electric layer 20 begins to be reversed, and therefore the electric field (+ 0.6E) at this point D can be defined as the predetermined electric field as at the point B.

[0069] Then, according to the electric field in the positive direction is gradually stronger, polarization inversion progresses around the surface of the pressure conductive layer 20, so that the direction of the direction and the electric field of polarization of pressure conductive layer 20 matches. Therefore, the step from the point D to the point A can also be called a repolarization processing step.

As described above, in order to evaluate whether the bending displacement characteristic has symmetry or asymmetry, it is necessary to measure with an electric field sufficiently larger than the predetermined electric field (± 0.6E). However, when measured at a slightly larger field than the predetermined electric field, if the asymmetry is a unique characteristic of the pressure Denmoto element according to the present embodiment can not determine occurs.

Therefore, in order to determine the asymmetry of the bending displacement characteristic, an electric field that is four times or more the electric field (defined here as the predetermined electric field) at which the direction of polarization partially begins to invert is bent alternately. It is desirable to evaluate displacement characteristics.
In other words, if the absolute displacement amount is increased and the measurement is performed, the asymmetry of the bending displacement characteristic can be easily evaluated.

[0072] For example, in the pressure Denmoto element according to the conventional example, because the coercive electric field is ± 0.5E, the positive direction of an electric field +
The measurement may be performed at 2.0E or more and an electric field in the negative direction of −2.0E or less. In the pressure Denmoto <br/> element according to the present embodiment, since the coercive electric field is ± 0.6E, a positive direction of an electric field + 2.4E above, the negative direction of the electric field -2.4
The measurement may be performed at E or less.

In FIG. 10B, the bending displacement characteristic is measured by alternately applying an electric field (± 3E) which is sufficiently larger than the predetermined electric field (± 0.6E). In this case, the peak value of the electric field in the positive direction (point The displacement amount ya in A) is 0.8 Δy, and the displacement amount yc at the peak value (point C) of the negative electric field is 2.
6Δy, and the relationship is yc = 3.25ya.

Next, the dimensional relationship for giving the bending displacement characteristic asymmetry will be described. First, when looking at the thickness y of the distance x and the pressure conductive layer 20 between the pair of electrodes 22a and 22b, as shown in FIG. 14, 1 ≦ x ≦ 200 [mu]
m, 1 ≦ y ≦ 100 μm, and y = ax, so that the range of 1/10 ≦ a ≦ 100 is satisfied.

Particularly, the proportional constant a is preferably 1
/ 5 ≦ a ≦ 10, more preferably 1/2 ≦ a ≦
It is 5. In this case, 1 ≦ x ≦ 60 μm, 1 ≦ y ≦ 40
If μm is satisfied, when an electric field is applied in the direction opposite to the polarization direction,
Since the pressure conductive layer 20 reversed easily its polarization direction to an appropriate depth, it is increased the amount of displacement effectively, optimal made as the actuator unit 12.

Here, when the plane shape of the pair of electrodes 22a and 22b is spiral, the distance x between the pair of electrodes 22a and 22b is, for example, as shown in FIG. One normal R from the peripheral edge
When 1 is subtracted, it indicates the distance between the starting point Q1 of the normal R1 and the intersection Q2 of the normal R1 and the inner peripheral edge of the other electrode 22b.

When the pair of electrodes 22a and 22b has a multi-branched planar shape, as shown in FIG. 15B,
For example, when one normal line R2 is drawn from the outer peripheral edge of the branch portion 30 of one electrode 22a, the starting point Q of the normal line R2 is drawn.
3 and the normal line R2 and the intersection point Q4 between the inner peripheral edge of the branch portion 32 of the other electrode 22b.

[0078] Next, when viewed thickness z of the vibrating section 16 and the thickness y of the pressure conductive layer 20, as shown in FIG. 16, 1 ≦ y ≦ 1
It is set to 00 μm, 1 ≦ z ≦ 50 μm, and has a relation of y = bz so as to satisfy the range of ⅕ ≦ b ≦ 10. In particular, the proportional constant b is preferably 1/3 ≦ b ≦ 5. In this case, 1 ≦ y ≦ 40 μm,
Satisfies the 1 ≦ z ≦ 20 [mu] m, since during the application of the electric field polarization direction opposite to the direction, pressure conductive layer 20 is easily its direction of polarization is inverted to a suitable depth, increased the amount of displacement effectively, the actuator It is optimal as the part 12.

[0079] Further, in the pressure Denmoto element according to the present embodiment, as shown in FIGS. 17 and 18, the vibration portion 16
It is preferable that the sectional shape at the shortest dimension m passing through the center of satisfies the following condition. 17 and 18
In order to avoid complication of the drawing, the pair of electrodes 2
Descriptions of 2a and 22b are omitted.

That is, as shown in FIG. 17B, from the reference line L formed by connecting one outermost minimum point P1 close to the fixed portion 18 and the other outermost minimum point P2,
At least a portion of the upper surface in the vicinity of the center portion of the pressure conductive layer 20 is that protrudes in a direction opposite to the vibrating section 16 with no-voltage-loaded state (state of the electric field E = 0).

[0081] Here, the vicinity of the central portion of the pressure conductive layer 20, as shown in FIG. 17A, in the shortest dimension m, the upper surface and the respective one of the boundary boundary between the upper surface of the vibration portion 16 of the fixed portion 18 When defining the point K1 and the other boundary point K2 and setting the shortest dimension to be 100, a range a1 of 30% from the one boundary point K1 toward the center of the shortest dimension m and the other boundary point K2. 3 toward the center of the shortest dimension m
It refers to the central 40% range a3, excluding the 0% range a2.

Further, as shown in FIG. 17B, the one outermost minimum point P1 is the pressure at the shortest dimension m.
Of the plurality of minimum points formed on the projection line of the one principal surface of the electric layer 20 and the upper surface of the vibrating portion 16 with respect to the shortest dimension surface, it means the minimum point closest to the one boundary point K1, and the other minimum point. The outer minimum point P2 refers to the minimum point closest to the other boundary point K2 among the plurality of minimum points.

In this case, when the shortest dimension is 100, it exists within a range of 40% (one minimum point existing region b1) from the one boundary point K1 toward the center of the shortest dimension m, Further, the minimum point closest to one boundary point K1 is recognized as one outermost minimum point P1, and the range of 40% from the other boundary point K2 toward the center of the shortest dimension m (the other minimum point existence region). The minimum point existing in b2) and closest to the other boundary point K2 is recognized as the other outermost minimum point P2.

The outermost local minimum points P1 and P2 are shown in FIG. 17B.
17A and 17B, it may be below the upper surface of the fixed portion 18, or may be above the upper surface of the fixed portion 18 as shown in FIG. 17C.

Incidentally, as shown in FIG. 18A, for example, when the other outermost minimum point P2 does not exist in the other minimum point existing region b2, the other boundary point K2 is regarded as the other outermost minimum point P2. Be certified. This is one of the outermost minimum points P
1 is the same. Further, as shown in FIG. 18B, when the outermost local minimum points P1 and P2 do not exist in both local minimum point existence regions b1 and b2, respectively, one boundary point K1 and the other boundary point K2 are respectively one maximum point. It is recognized as the outer minimum point P1 and the other outermost minimum point P2.

[0086] Then, the condition, i.e., "at least a portion of the upper surface in the vicinity of the center portion of the reference line pressure conductive layer 20 than L is possible. Which projects in the direction opposite to the vibrating section 16 with no-voltage-loaded state" in that condition , The shortest dimension length is m
And the protrusion amount t is m / 1000 ≦ t ≦ m / 1
It is more preferable to satisfy 0.

By satisfying the above conditions, it is possible to cause the manufactured actuator section 12 to make a large displacement in one direction without fail, and it is possible to achieve an improvement in yield when used in various electronic devices. .

[0088] Thus, in the pressure Denmoto element according to the present embodiment, a pair of electrodes 22a and 22b formed with the main actuator element 24 on one major surface of the pressure conductive layer 20 and the piezoelectric layer 20 And a pair of electrodes 22a and 2a
Since the displacement characteristic of the actuator element 12 by more than four times the applied electric field of a predetermined electric field between 2b so as to be asymmetrical about a reference electric field point, the electric field in the opposite direction after the polarization treatment against pressure conductive layer 20 when subjected, in the vicinity of the surface of the pressure conductive layer 20, since the electric field strength is large, but its polarization direction is the same as the direction of the reversed electric field, deep portion of the pressure conductive layer 20 is the electric field strength thereof Is small, the polarization direction will not be inverted. That is, the pressure conductive layer 2
At 0, results in two types of polarization exist, will function as a pseudo-bimorph pressure Denmoto child.

[0089] As a result, the vicinity of the surface of the pressure conductive layer 20, the strain direction in the deep portion becomes opposite to each other, and the convex displaced in one direction as a whole, the amount of displacement, the pseudo-bimorph effects Will be very large.

[0090] Particularly, in pressure Denmoto child according to the present embodiment,
Since the displacement characteristics are asymmetrical in the positive and negative directions of the electric field around the reference electric field point (point where the electric field E = 0), for example, at two peak values of the electric field that periodically change, There is a difference in the amount of flexural displacement. Thus, and the relative displacement amount at the no-voltage-loaded state and the voltage application state, the greater the relative displacement amount at the state of applying a reverse electric field from each other, facilitating the control of the case of using the pressure Denmoto element as an actuator And improved sensitivity when used as a sensor.

[0091] In the pressure Denmoto element according to the present embodiment, the distance between the pair of electrodes 22a and 22b x (1 [mu]
m ≦ x ≦ 200μm), the thickness of the pressure conductive layer 20 y (1
(μm ≦ y ≦ 100 μm), there is a relation of y = ax and 1/10 ≦ a ≦ 100.

In this case, the pair of electrodes 22a and 22a
As a displacement characteristic of the actuator portion 12 due to an applied electric field between b, as shown in FIG. 10B, a reference electric field point (electric field E =
It is possible to obtain a characteristic that is asymmetrical about the point 0).

[0093] In the pressure Denmoto element according to the present embodiment, the recess 14 at a location where the vibration portion 16 and the fixed portion 18 formed integrally with the ceramics, corresponding to the vibration part 16
To form, since the vibrating portion 16 is made to be thin, the fixing portion 18 and the vibrating portion 16 becomes possible to easily manufacture, advantageous in reducing the production cost of the pressure Denmoto child Becomes

The base 10 made of ceramics
For fixing portion 18 and the thin resonating section 16 of the thick by providing the concave portion 14 is shape that is formed, the vibrating unit 16 is sensitive to the displacement of the pressure conductive layer 20, to changes in voltage signal Therefore, the vibrating portion 16 having high followability can be obtained. Further, since the rigidity of the boundary portion between the vibrating portion 16 and the fixed portion 18 is sufficiently secured, the damage due to the fatigue of the boundary portion due to the vibration of the vibrating portion 16 is less likely to occur.

[0095] In the pressure Denmoto element according to the present embodiment, the thickness of the pressure conductive layer 20 y (1μm ≦ y ≦ 100μ
m), and the thickness of the vibrating portion 16 is z (1 μm ≦ z ≦ 50 μm)
, And y = bz, and 1/5 ≦ b
Since ≦ 10, the bending displacement characteristics of the actuator portion 12 due to the applied electric field between the pair of electrodes 22a and 22b can be asymmetrical with respect to the reference electric field point, as shown in FIG. 10B.

[0096] The pressure Denmoto element according to the embodiment, although a particular pair of electrodes 22a and 22b of the planar shape of the spiral shape or multi-vessel shape, as shown in FIG. 19, may be a comb-shaped Absent. In this case, the shape of the vibrating portion 16 has an aspect ratio of 0.25 or less, or 4.0 or more,
It is preferable to form a pair of comb-shaped electrodes so that the arrangement direction of a large number of comb teeth is along the longitudinal direction of the vibrating portion. If this condition is satisfied, even if the pair of electrodes 22a and 22b have a comb shape, the same effect as the spiral shape or the multi-branched shape can be obtained.

However, the vibrating portion 16 has an aspect ratio of 0.25 to 4.0, preferably 0.5 to 2.0, and the plane shape of the pair of electrodes 22a and 22b is spiral or multi-branched. The shape is most preferable for increasing the relative displacement amount.

Next, selection of each constituent member of the actuator section 12, particularly the material of each constituent member will be described.

First, the vibrating portion 16 is preferably made of a highly heat resistant material. The reason is that the actuator portion 12 does not use a material having poor heat resistance such as an organic adhesive and the fixing portion 1
If a structure for supporting the direct vibration portion 16 by 8, at least when the pressure conductive layer 20 formed, since the vibration portion 16 is prevented from deterioration, vibration unit 16 is preferably a highly heat-resistant material.

Further, the vibrating portion 16 has one electrode 2 of the pair of electrodes 22a and 22b formed on the base body 10.
In order to electrically separate the wiring leading to 2a (vertical selection line 48: see FIG. 21) and the wiring leading to the other electrode 22b (signal line 50: see FIG. 21), an electrically insulating material is preferable. .

Therefore, the vibrating portion 16 may be made of a highly heat-resistant metal or a material such as enamel whose metal surface is coated with a ceramic material such as glass, but ceramic is most suitable.

As the ceramics constituting the vibrating portion 16, for example, stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, aluminum nitride, silicon nitride, glass, a mixture thereof or the like can be used. it can. Stabilized zirconium oxide is, it has high mechanical strength even if a small thickness of the vibrating section 16, the high toughness, such that the chemical reactivity of the pressure conductive layer 20 and the pair of electrodes 22a and 22b are small Therefore, it is particularly preferable. Stabilized zirconium oxide includes stabilized zirconium oxide and partially stabilized zirconium oxide. Stabilized zirconium oxide does not cause a phase transition because it has a crystal structure such as a cubic crystal.

On the other hand, zirconium oxide undergoes a phase transition between a monoclinic system and a tetragonal system at around 1000 ° C., and cracks may occur during this phase transition. The stabilized zirconium oxide contains 1 to 30 mol% of a stabilizer such as calcium oxide, magnesium oxide, yttrium oxide, scandium oxide, ytterbium oxide, cerium oxide or an oxide of a rare earth metal. In order to increase the mechanical strength of the vibrating portion 16, the stabilizer preferably contains yttrium oxide. At this time, yttrium oxide is preferably contained in an amount of 1.5 to 6 mol%, more preferably 2 to
4 mol% is contained, and it is preferable that 0.1 to 5 mol% of aluminum oxide is further contained. Furthermore, 0.1 to 10 mol% of titanium oxide or 0.1 to 10 mol%
It is also preferable to contain 10 mol% of aluminum oxide + titanium oxide from the viewpoint of increasing the relative displacement amount and ensuring close contact with the piezoelectric material.

The crystal phase may be a cubic + monoclinic mixed phase, a tetragonal + monoclinic mixed phase, a cubic + tetragonal + monoclinic mixed phase, and the like. It is most preferable from the viewpoint of strength, toughness and durability that the main crystal phase is tetragonal or a mixed phase of tetragonal and cubic.

When the vibrating section 16 is made of ceramics,
Although a large number of crystal grains constitute the vibrating portion 16, the average grain size of the crystal grains is 0.0 to increase the mechanical strength of the vibrating portion 16.
The thickness is preferably 5 to 2 μm, more preferably 0.1 to 1 μm.

The fixed portion 18 is preferably made of ceramics, but may be made of the same ceramic as that of the vibrating portion 16 or may be made of a different material. As the ceramics forming the fixed portion 18, similar to the material of the vibrating portion 16,
For example, stabilized zirconium oxide, aluminum oxide, magnesium oxide, titanium oxide, spinel, mullite, aluminum nitride, silicon nitride, glass, a mixture thereof, or the like can be used.

[0107] Materials particularly, the substrate 10 used in the pressure Denmoto child according to the present embodiment, material composed mainly of zirconium oxide, as a main component material mainly composed of aluminum oxide, or mixtures thereof Etc. are suitably adopted. Among them, those containing zirconium oxide as a main component are more preferable. Clay or the like may be added as a sintering aid, but it is necessary to adjust the aid component so as not to include excessively vitrifying substances such as silicon oxide and boron oxide. Because they vitrify easily material, albeit advantageous in joining the substrate 10 and the pressure conductive layer 20 to promote the reaction between the substrate 10 and the pressure conductive layer 20, the composition of a given pressure conductive layer 20 This is difficult to maintain, and as a result, it becomes a cause of deteriorating the device characteristics.

That is, it is preferable to limit the silicon oxide and the like in the substrate 10 to a weight ratio of 3% or less, more preferably 1% or less. Here, the main component is 50 by weight.
A component present in a proportion of not less than%.

[0109] As the material of the pressure conductive layer 20, but can be preferably used a piezoelectric ceramic may be electrostrictive ceramics or ferroelectric ceramics. Furthermore, the material is not limited to ceramics, and may be a piezoelectric body made of a polymer represented by PVDF (polyvinylidene fluoride) or a composite of these polymers and ceramics.

[0110] Materials as a piezoelectric material to give film-like <br/> pressure conductive layer 20 in the actuator body 24, which preferably mainly composed of lead zirconate titanate (PZT system),
A material containing lead magnesium niobate (PMN-based) as a main component, a material containing lead nickel niobate (PNN) as a main component, a material containing lead manganese niobate as a main component, and a lead antimony stannate as a main component. Materials, lead zinc niobate-based materials, lead titanate-based materials, lead magnesium tantalate-based materials, lead nickel tantalate-based materials, and composites of these. Material or the like is used.

Furthermore, lanthanum, barium, niobium, zinc, cerium, cadmium, chromium,
Cobalt, antimony, iron, yttrium, tantalum,
A predetermined additive is appropriately added to the material such as a material containing an oxide such as tungsten, nickel, manganese, lithium, strontium, or bismuth, or other compound thereof as an additive, for example, a PLZT system. Those added are also preferably used.

Among these piezoelectric materials, a material containing a lead magnesium niobate, lead zirconate, and lead titanate as a main component, lead nickel niobate, lead magnesium niobate, lead zirconate, and titanium. Material containing lead oxide as a main component, lead magnesium niobate, nickel lead tantalate, lead zirconate and lead titanate, or lead magnesium tantalate and lead magnesium niobate the material is advantageously used for a major component composed of lead zirconate and lead titanate, it is recommended as the material of the case of forming the pressure conductive layer 20 in the thick film formation method such as screen printing.

[0113] In the case of multi-component piezoelectric material, the piezoelectric characteristics change depending on the composition ingredients, lead magnesium niobate is preferably employed in <br/> pressure Denmoto element according to this embodiment -
Lead zirconate-lead titanate ternary material, lead magnesium niobate-lead nickel tantalate-lead zirconate-lead titanate, and lead magnesium tantalate-lead magnesium niobate-lead zirconate-lead titanate In the four-component material, the composition near the phase boundary of pseudocubic-tetragonal-rhombohedral is preferable, and lead magnesium niobate: 1
5 to 50 mol%, lead zirconate: 10 to 45 mol%, lead titanate: 30 to 45 mol%, lead magnesium niobate: 15 to 50 mol%, lead nickel tantalate:
10 to 40%, lead zirconate: 10 to 45 mol%, lead titanate: 30 to 45 mol%, further lead magnesium niobate: 15 to 50 mol%, lead magnesium tantalate: 10 to 40 mol% , Lead zirconate: 10 to 45 mol% and lead titanate: 30 to 45 mol% are advantageously used because of their high piezoelectric constant and electromechanical coupling coefficient.

[0114] pressure conductive layer 20 may be a dense, it may be porous, if porous, a preferable porosity of 40% or less.

Then, the vibrating portion 16 in the base 10
The thickness and the thickness of the pressure conductive layer 20 formed on the vibrating section 16 is preferably a thickness of the same dimensions. This is because (if different order of magnitude or more) thickness of the vibrating section 16 is extremely, pressure electrostatic
Becomes larger than the thickness of the layer 20, with respect to the firing shrinkage of the pressure conductive layer 20, to work as the vibration portion 16 prevents the contraction stress at the interface between the pressure conductive layer 20 and the substrate 10 is increased, peeling It will be easier. Conversely, the dimension of the thickness if the same level, the base body 10 to the firing shrinkage of the pressure conductive layer 20 (vibrating section 16)
Is easy to follow, which is suitable for integration. Specifically, the thickness of the vibrating portion 16 is preferably 1 to 50 μm, more preferably 3 to 50 μm, and 3 to 20 μm.
Is more preferable. On the other hand, pressure conductive layer 20, 1 to 100 [mu] m is preferable as a thickness, more preferably 3 to 50 [mu] m, even more preferred is 5 to 40 m.

[0116] pair of electrodes 22a and 22b formed on the pressure conductive layer 20 is set as a suitable thickness depending on the application, is preferably a thickness of 0.01 m to 50 m,
0.1 to 5 μm is more preferable. The pair of electrodes 22a and 22b are preferably solid at room temperature and made of a conductive metal. For example, aluminum, titanium, chromium, iron, cobalt, nickel, copper,
Zinc, niobium, molybdenum, ruthenium, rhodium,
Examples include simple metals or alloys containing silver, tin, tantalum, tungsten, iridium, platinum, gold, lead and the like. It goes without saying that these elements may be contained in any combination.

[0117] Next, a method for manufacturing a pressure Denmoto element according to the present embodiment. The base 10 including the vibrating portion 16 and the fixing portion 18 can be integrated by stacking a molding layer, which is a green sheet or a green tape, by thermocompression bonding and then firing. For example, in the substrate 10 of FIG. 1, two layers of green sheets or green tapes are laminated, but a through hole having a predetermined shape to be the recess 14 may be provided in the second layer before lamination.

Further, a molding layer is produced by pressure molding using a molding die, casting molding, injection molding, etc., and the recesses 14 etc. are provided by mechanical processing such as cutting, grinding, laser processing, punching by press processing. May be. In FIG. 1, 2
Although it has a layered structure, the substrate 1 is used as the third and fourth layers.
The rigidity of 0 may be improved, or layers used as a backside wiring board may be laminated at the same time.

Next, the actuator body 24 is formed on the vibrating portion 16 of the base 10. In this case, by forming the pressure conductive layer 20 by a tape molding method using a press molding method or the slurry raw material using a die, on the vibrating section 16 in the base body 10 before firing the pre-fired pressure conductive layer 20 laminating by thermal compression bonding, simultaneously fired to a method of forming a <br/> pressure conductive layer 20 on the vibrating portion 16 of the body 10, there is a film forming method described below.

[0120] film formation method is a method of laminating the pressure conductive layer 20 and the pair of electrodes 22a and 22b in this order on the vibrating section 16, for example, thick film methods such as screen printing, coating of dipping Method, ion beam, sputtering, vacuum deposition, ion plating, chemical vapor deposition (C
VD), a thin film method such as plating, or the like is appropriately used. Wiring connected to the pair of electrodes 22a and 22b (vertical selection line 48
Also, the thick film method and the thin film method are used to form the signal line 50: see FIG. 21) and the terminal pad.

[0121] pressure Denmoto element according to the present embodiment, as an example, for example, the following method is adopted. First,
A pressure is applied to the vibrating portion 16 of the substrate 10 by a screen printing method.
The electric layer 20 is formed. Then, firing is performed to form the base 10
Bonding the pressure conductive layer 20 on the vibrating portion 16. In this case, to improve the bonding strength to the base 10 and the pressure conductive layer 20, to favor the integration of these substrates 10 and pressure conductive layer 20, pressure conductive
The firing of the layer 20 is preferably carried out in a closed container in an atmosphere of piezoelectric material. More preferably, it is desirable to increase the atmosphere concentration.

The atmosphere firing is performed by the following method or the like.

(1) A powder of the same component system as the piezoelectric material is placed together in an airtight container as an evaporation source.

(2) As the composition of the piezoelectric material, the lead component is made excessive beforehand.

(3) A plate of piezoelectric material is used as a setter.

The firing temperature is preferably 900 to 1400 ° C, more preferably 1100 to 1400 ° C.

[0127] laminating After bonding between the substrate 10 and the pressure conductive layer 20 is completed, the wiring layer including a pair of electrodes 22a and 22b by screen printing. The pattern of this wiring layer is
For example, as shown in FIG. 21, the pattern of the vertical selection line 48, the pattern of the signal line 50, and the electrode pattern,
At this stage (screen printing stage), the electrode pattern is not a spiral shape as shown in FIG. 4 or a multi-branch shape as shown in FIG. 5, but a circular shape.

Thereafter, by evaporating a required portion of the circular electrode pattern with, for example, an excimer laser, the electrode pattern is patterned into a spiral shape as shown in FIG. 4 or a multi-branch shape as shown in FIG. 22b
And

After the patterning with the excimer laser is completed, a heat treatment is completed to complete the formation of the actuator body 24 on the substrate 10. The heat treatment is not always necessary when the pair of electrodes 22a and 22b are formed by the thin film method.

[0130]

EXAMPLES Next, the display device will be described according to the embodiment applied to a display device pressure Denmoto element according to the present embodiment.
In addition, the same code | symbol is attached | subjected about the thing corresponding to FIG. 1, and the overlapping description is abbreviate | omitted.

As shown in FIG. 20, the display device according to this embodiment is provided with an optical waveguide plate 42 into which the light 40 is introduced and a large number of actuator portions provided so as to face the back surface of the optical waveguide plate 42. Drive unit 44 in which 12 is arranged corresponding to pixels
Is configured.

The front and back surfaces of the optical waveguide plate 42 are flat and smooth, and the light introduced inside is totally reflected on the front and rear surfaces without being transmitted to the outside of the optical waveguide plate 42. It has a light refractive index, and it needs to have a uniform and high transmittance in the visible light wavelength region. The material is not particularly limited as long as it has such characteristics. Specifically, for example, glass, quartz, translucent plastic such as acrylic, translucent ceramics, or the like, or a different refractive index. A general structure is a multi-layer structure of a material having the above or a structure having a coating layer on the surface.

The drive section 44 has a base 10 made of, for example, ceramics, and the actuator section 12 is arranged at a position corresponding to each pixel of the base 10. The substrate 10 is arranged such that one main surface faces the back surface of the optical waveguide plate 42, the one main surface is a continuous surface (flush), and the other main surface corresponds to each pixel. Each position has a recess 14.

On each actuator section 12, a displacement transmitting section 46 is connected, which enlarges the contact area with the optical waveguide plate 42 and makes the area according to the pixel. This displacement transmitting section 46
Has a plate member 46a defining a substantial light emitting area and a displacement transmitting member 46b for transmitting the displacement of the actuator portion 12 to the plate member 46a.

It is preferable that the displacement transmitting member 46b has such a hardness that the displacement of the actuator portion 12 can be directly transmitted to the optical waveguide plate 42. Therefore, as the material of the displacement transmitting member 46b, rubber, organic resin, organic resin film, organic adhesive film, glass and the like are preferable. However, the material is not the electrode layer itself or the piezoelectric material or the above-mentioned ceramics. It doesn't matter. Most preferably, an organic resin or organic adhesive film of epoxy type, polyphenylene sulfide type, polyester type, polyimide type, acrylic type, silicone type, polyolefin type or the like is used. Furthermore, it is also effective to mix a filler with these materials to suppress curing shrinkage and expansion.

As the material of the plate member 46a, in addition to the material of the displacement transmitting member 46b, epoxy type, acrylic type,
A material in which a ceramic powder having a high refractive index, such as a zirconia powder, a titania powder, a lead oxide powder, or a mixed powder thereof, is highly dispersed in an organic resin such as a silicone-based resin is desirable in terms of light emission efficiency and flatness maintenance. The average particle size of the ceramic powder at this time is preferably 1 μm or less,
More preferably, it is 5 μm or less. In this case, resin weight: ceramic powder weight = 1: (0.1-10) is preferable. Furthermore,
A glass powder having an average particle diameter of 0.5 to 10 μm in the composition is used in a volume ratio of 1: (0.1 to 1.
0) Addition in a ratio of {= ceramic powder: glass powder} is preferable because the contact property with the surface of the optical waveguide plate 42 and the releasability are improved.

The plate member 46a of the displacement transmitting section 46 has a flatness and a smoothness (Ra) in a portion (surface) which is in contact with the optical waveguide plate 42.
However, it is preferable to make it sufficiently smaller than the displacement amount of the actuator portion 12, specifically, 1 μm or less, more preferably 0.5 μm, and particularly preferably 0.1 μm or less. However, the flatness of the portion (surface) of the displacement transmitting unit 46 that contacts the optical waveguide plate 42 is determined by the displacement transmitting unit 46 being the optical waveguide plate 4.
The flatness is not limited to the above, as long as it is important for reducing the gap in the state of being in contact with 2, and the contact portion is deformed in the state of being in contact.

The displacement transmitting portion 46 is connected to the actuator body 24 by connecting the displacement transmitting portion 46 with an adhesive when the above-mentioned materials are used for the displacement transmitting portion 46. It may be performed by forming a solution, paste or slurry of the above-mentioned material on the upper portion of the actuator body 24 by a method such as coating. The displacement transmitting member 46b and the plate member 46a may be integrally formed of the same material. That is, the displacement transmitting portion 46 may have the functions of the displacement transmitting member 46b and the plate member 46a.

As shown in FIG. 21, the number of vertical selection lines 48 corresponding to the number of rows of a large number of pixels and the number of wirings corresponding to the number of columns of a large number of pixels are connected to the electrodes 22a and 22b. Signal line 50.

Each vertical selection line 48 is electrically connected to one electrode 22a of each pixel (actuator section) 12, and each signal line 50 is connected to the other electrode 22b of each pixel 12.
Electrically connected to.

Further, each vertical selection line 48 is derived from one electrode 22a of the pixel 12 in the previous column and connected to one electrode 22a of the pixel 12 and is connected in series for one row. Has become.

The signal line 50 is a main line 50a extending in the column direction.
And the other electrode 2 of each pixel 12 branched from the main line 50a
It consists of a branch line 50b connected to 2b. Each vertical selection line 4
The voltage signal is supplied to the wiring board (not shown) (base 1
0 to the other main surface) to through hole 5
2, the voltage signal is also supplied to each signal line 50 from the wiring board (not shown) through the through hole 54.

Various arrangement patterns of the through holes 52 and 54 are conceivable, but in the example of FIG.
When the number of rows is M and the number of columns is N, the through hole 52 of the vertical selection line 48 is N = M or N> M.
It is formed in the vicinity of a pixel of n rows and n columns (n = 1, 2 ...) And at a position close to a signal line (main line) of (n−1) th column,
When N <M, (αN + n) rows and n columns (α =
It is formed in the vicinity of the pixel of 0, 1 ... (Quarter of M / N-1) and at a position closer to the signal line (main line) of the (n-1) th column.

On the other hand, the through hole 54 of the signal line 50 is
In the case of N = M or N <M, it is on the main line 50a of each signal line 50 and in n rows and n columns (n = 1, 2 ...
In the case where N> M, it is formed on the main line 50a of each signal line 50,
In addition, it is formed at a position close to the pixel 12 in the n-th row (βM + n) column (β = 0, 1 ... (N / M quotient-1)). In addition, the through hole 52 of the vertical selection line 48 is connected to the signal line 50.
Unlike the above case, since it is not formed on the vertical selection line 48, a relay conductor 56 for electrically connecting them is formed between the through hole 52 and the one electrode 22a.

An insulating film made of a silicon oxide film, a glass film, a resin film or the like is provided at the intersection of each vertical selection line 48 and each signal line 50 in order to insulate the mutual wirings 48 and 50 from each other. 58 (indicated by a chain double-dashed line) is interposed.

[0146] The planar shape of the pair of electrodes 22a and 22b, a spiral (see Fig. 4), there is a multi-branch shape (see FIG. 5), the planar shape of the vibration part 16, the planar shape of the pressure conductive layer 20 Further, as the outer peripheral shape formed by the pair of electrodes 22a and 22b, in addition to the circular shape shown in FIG. 21,
There are oval shapes shown in FIGS. 22 and 23 and elliptical shapes shown in FIG.

[0147] Further, as shown in FIG. 25, the planar shape of the planar shape and pressure conductive layer 20 of the vibrating portion 16 together with the rectangular shape,
As shown in FIG. 26, the corners have sharp corners,
The plane shape and the shape of the pressure conductive layer 20 of the vibrating portion 16 together with a polygonal shape (e.g. octagonal), it is preferable that a shape in which each apex angle portions rounded.

[0148] The shape of the vibrating section 16, the outer peripheral shape shaped planar shape of the pressure conductive layer 20, by a pair of electrodes 22a and 22b may be a combination of circles and ellipses may be a combination of rectangular and oval It is not particularly limited.

In the example of FIG. 21, the arrangement of the actuator portions (pixels) 12 on the substrate 10 is shown as a matrix, but in addition, as shown in FIG. The parts 12 may be arranged in a staggered manner.

In the case of the arrangement pattern of FIG. 24, since the arrangement of the actuator portions (pixels) 12 for each row is staggered, the vertical selection lines 48 for each row are arranged.
The line (indicated by the alternate long and short dash line a) connecting the lines is zigzag. As shown by a broken line b on the wiring board (not shown), two signal lines 50 are provided in the zigzag-shaped pixels 12 at two locations corresponding to the pixels (actuator section) 12 located vertically upward, for example. The signal lines 50 of FIG.

In FIG. 24, among the pixels arranged in a staggered pattern, for example, the other electrode 22b of the pixel (actuator portion) 12 located on the upper side in the vertical direction has the two signal lines 50 and Signal line 5 on the right side of 50
0 is electrically connected to the relay conductor 60 and the through hole 62, and the other electrode 22b of the pixel (actuator portion) 12 located on the lower side in the vertical direction is one of the two signal lines 50 and 50 which are adjacent to each other. , Left signal line 50
Is electrically connected through the relay conductor 64 and the through hole 66.

Next, the operation of the display device according to the above embodiment will be described. First, the operation of each actuator section 12 will be described, and then the operation of the display device itself will be described.

First, in the display device according to the present embodiment shown in FIG. 20, polarization processing (initial polarization processing) is performed on each pixel (actuator portion) 12 separately from its driving. This initial polarization treatment is performed by applying an electric field (+ 5E) that exceeds the range of use of the electric field used as the actuator (for example, the range of + 3E to -3E in FIG. 10) at an appropriate temperature for, for example, 7 hours. Thus, pressure conductive layer 20 in each pixel is polarized in the same direction as the applied electric field.

When the initial polarization process is completed for all the pixels, the voltage application between the pair of electrodes 22a and 22b is stopped and the voltage is not applied.

In driving the display device, basically three operations (ON selection, ON selection,
The image is displayed by performing OFF selection and non-selection.

As shown in FIG. 27A, the ON selection is performed by the pair of electrodes 22a of the pixel 12 in a predetermined selection period Ts.
And 22b by applying a voltage Va to generate a negative electric field Ea (see FIG. 10B) between the pair of electrodes 22a and 22b. In the OFF selection, as shown in FIG. 27B, a voltage Vd is applied to the pair of electrodes 22a and 22b of the pixel 12 in a predetermined selection period Ts, and a negative or positive electric field is applied between the pair of electrodes 22a and 22b. This is performed by generating Ed (see FIG. 10B).

27A or 27B, the non-selection is performed by applying the voltage Vf or Vg to the pair of electrodes 22a and 22b of the pixel in a period other than the selection period Ts (non-selection period Ta). This is performed by generating an electric field Ef or Eg in the positive direction (see FIG. 10B) between the electrodes 22a and 22b. In the non-selection period Ta,
As with the initial polarization treatment since the electric field in the positive direction is generated, pressure conductive layer 20 of the pixels in a non-selected state for in the same polarization treatment (referred to as convenience repolarization process) is performed.

The driving operation of the display device according to the present embodiment will be described in detail. Based on the input of an image signal to the display device, the vertical selection line 48 to the vertical selection line 48 by the vertical shift circuit formed of, for example, a shift register is displayed. According to the potential supply,
For example, the first row, the second row, ...
Pixel groups are selected one by one like the row,
In the selected row, the potential is supplied to the signal line 50 relating to the pixel 12 to be ON-selected for a predetermined selection period Ts from a horizontal shift circuit configured by a shift register, for example.

As a result, in the pixel 12 selected to be ON by the vertical shift circuit and the horizontal shift circuit, a negative predetermined potential is applied to one electrode 22a thereof, and a positive potential is applied to the other electrode 22b thereof, so that a pair of electrodes is formed. The voltage between the electrodes 22a and 22b is set to the predetermined negative voltage Va (see FIG. 27A).

At this time, as shown in FIGS. 10B and 13A, for example, an electric field Ea in the negative direction (for example, −3E: in the direction opposite to the electric field at the time of initial polarization treatment or non-selection) is provided between the pair of electrodes 22a and 22b. An electric field) is generated, and the actuator portion 12 in the pixel is displaced in one direction by about 2.6Δy.

This state shows the ON selection state when viewed on the display device. In this ON-selected state, the displacement transmitting section 46 is moved to the optical waveguide plate 42 by the convex deformation of the actuator section 12.
The displacement transmitting section 46 comes into contact with the optical waveguide plate 42 after being displaced to the side.

The displacement transmitting portion 46 contacts the back surface of the optical waveguide plate 42 in response to the displacement of the actuator portion 12. When the displacement transmitting portion 46 contacts the rear surface of the optical waveguide plate 42, for example, light is transmitted. The light 40 that has been totally reflected in the corrugated plate 42 passes through the back surface of the optical waveguide plate 42 and is transmitted to the displacement transmitter 46.
Of the displacement transmitting portion 46, and is scattered and reflected by the surface of the displacement transmitting portion 46.

The displacement transmitting section 46 scatters and reflects the light transmitted through the back surface of the optical waveguide plate 42.
It is provided in order to make the contact area with 2 larger than a predetermined value. That is, the light emitting area is defined by the contact area between the displacement transmitting section 46 and the optical waveguide plate 42.

The contact between the displacement transmitting section 46 and the optical waveguide plate 42 means that the displacement transmitting section 46 and the optical waveguide plate 42 are at a distance equal to or less than the wavelength of the light (light introduced into the optical waveguide plate 42) 40. Means to be located.

On the other hand, with respect to the pixels 12 that are not ON-selected or OFF-selected in the pixel group related to the row selected by the vertical shift circuit, the potential of the signal line 50 related to the pixel 12 is ON for a predetermined selection period Ts. A potential different from the potential at the time of selection is applied, a predetermined negative potential is applied to one electrode 22a of the pixel 12, and the other electrode 22a
When a negative or positive potential is applied to b, the voltage between the pair of electrodes 22a and 22b is a predetermined voltage Vd in the negative or positive direction.
(See FIG. 27B).

At this time, as shown in FIG. 10B, for example, a negative or positive electric field Ed (for example, -0.6E to + 0.6E) is generated between the pair of electrodes 22a and 22b,
The actuator unit 12 in the pixel is about -0.5.
It is displaced in one direction by Δy to 1Δy.

This state is OFF when viewed from the display device.
Indicates the selected state. In the OFF selection state, the displacement transmitting section 46 is separated from the optical waveguide plate 42 side by the displacement operation of the actuator section 12.

[0168] ON selection or OFF actuator unit 12 for the selected pixels in the subsequent non-selected state, the repolarization process, a pair of electrodes 22a and 22b formed on one direction (pressure conductive layer 20 is a free space In the direction of (1). In this non-selected state, voltage levels Vg and Vf (FIG. 27) on which voltage changes based on ON selection and OFF selection in other rows are superimposed.
A and FIG. 27B), the existence of this superposition component (crosstalk component) is in the non-selected state of the actuator unit 1.
Since the repolarization process is performed on 2 to some extent,
This will help restore the responsiveness of displacement to changes in the electric field. That is, the crosstalk component also serves to recover the responsiveness.

The voltage level for ON selection is the voltage level Vb (electric field Eb in FIG. 10B).
It suffices that the voltage level is in the negative direction than (for example, the voltage level corresponding to −2E), and the voltage level for performing the OFF selection is in the range of voltage levels Vc to Ve (FIG. 1).
At 0B, the electric field Ec (for example, −0.6E) to Ee (+
Any voltage level within a voltage level corresponding to the range of 0.6E) may be used. Further, the voltage level for performing the repolarization process may be a voltage level in the positive direction than the voltage level Ve (the voltage level corresponding to the electric field Ee (for example, + 0.6E) in FIG. 10B).

Next, the operation of the display device according to this embodiment will be described. First, for example, from the end of the optical waveguide plate 42, the light 4
0 is introduced. In this case, by adjusting the magnitude of the refractive index of the optical waveguide plate 42, all the light 40 is converted into the optical waveguide plate 4.
It does not transmit on the front and back surfaces of 2 and undergoes total internal reflection.

In this state, when a certain actuator section 12 is excited and the displacement transmitting section 46 corresponding to the actuator section 12 comes into contact with the back surface of the optical waveguide plate 42 at a distance equal to or less than the wavelength of light, all the elements are until then. The reflected light 40 is transmitted to the surface of the displacement transmitting portion 46 which is in contact with the back surface of the optical waveguide plate 42. The light 40 once reaching the surface of the displacement transmitting unit 46 is reflected by the surface of the displacement transmitting unit 46 and partially reflected in the optical waveguide plate 42 again as scattered light 70 (see FIG. 20). Most of the scattered light 70 is transmitted through the front surface of the optical waveguide plate 42 without being reflected by the optical waveguide plate 42.

That is, the presence or absence of light emission (leakage light) on the front surface of the optical waveguide plate 42 can be controlled by the presence or absence of contact of the displacement transmitting portion 46 on the back surface of the optical waveguide plate 42. Particularly, in the display device according to the present embodiment, the optical waveguide plate 42
In contrast to this, one unit for displacing the displacement transmitting section 46 in the contact / separation direction is one pixel, and a large number of these pixels are arranged in a matrix or in a zigzag pattern for each row. By controlling the displacement operation in each pixel according to the attribute of the signal, the image (characters, figures, etc.) corresponding to the image signal is displayed on the front surface of the optical waveguide plate as in the cathode ray tube and the liquid crystal display device. You can

Next, a case where the display device according to the present embodiment is applied to a color display system will be described. First, the principle of color development of the display device according to the present embodiment is the same as in the current color display system, that is, R (red), G (green) and B which are the three primary colors.
It is defined by the mixed method of (blue). Here, when it is considered that the maximum light emission time of RGB is divided into three, where T is the cycle of color development, and the ratio of the light emission time of RGB is 1: 1: 1 as shown in FIG. 28A, white light is emitted. Next, Fig. 28
As shown in B, the ratio of the emission time of RGB is 4: 1: 5.
If so, an intermediate color corresponding to the ratio is obtained.

Therefore, the control of the color development time may be performed by synchronizing the contact time between the optical waveguide plate 42 and the displacement transmitting section 46 with the color development cycle T to control the emission time of the three primary colors, or the emission of the three primary colors. It is also possible to control the contact time between the optical waveguide plate 42 and the displacement transmitting section 46 in synchronism with the period T for coloring the time.

As described above, the display device according to the present embodiment has an advantage that it is not necessary to increase the number of pixels as compared with the case of a monochrome screen even when applied to a color display system. is there.

In the above embodiment, the repolarization process for each pixel 12 is performed during the non-selection period.
In addition, from the end point of R light emission to the start point of next G light emission, from the end point of G light emission to the next start point of B light emission, from the end point of B light emission to the start point of next R light emission In the three periods of, the repolarization process may be performed by applying the same electric field as the initial polarization process. In this case, it may be combined with the repolarization process in the non-selection period.

The display device according to this embodiment can be used alone, and as shown in FIG. 29, the display device according to this embodiment can be used as one display element 74 of the large screen display device 72. Is. In the example of FIG. 29, an example is shown in which seven display elements 74 are arranged in the vertical direction and eighteen are arranged in the horizontal direction on the back surface of the light guide plate 76 having a large screen display area. In this case, the light guide plate 76 is made of a glass plate, an acrylic plate, or the like, which has a large light transmittance in the visible light region and is uniform, and wire bonding, soldering, and end face connectors are provided between the display elements 74. , Signals can be supplied to each other by connecting them by means of a rear surface connector or the like.

In the large screen display device 72 shown in FIG. 29, for example, the display device shown in FIG. 24 is used as a display device applied to each display element 74, and 32 pixels 12 are arranged in the horizontal direction. , 32 in the vertical direction are used. In the display device shown in FIG. 24, the arrangement of the pixels 12 in each row is staggered, and therefore the arrangement pitch of the pixels 12 in the horizontal direction can be made very small, and the number of pixels arranged in the horizontal direction and the arrangement of the pixels in the vertical direction are the same. If set to
The overall plane shape is a vertically long shape.

In the large screen display device 72 shown in FIG. 29, an example in which the display elements 74 including the optical waveguide plate 42 are arranged in a matrix on the plate surface of the large light guide plate 76 is shown. The large-screen display device 72 may be configured by omitting the light guide plate 76 and disposing the display elements 74 including the optical waveguide plate 42 in a matrix. in this case,
A large number of optical waveguide plates 42 arranged in a matrix also serve as the large-sized light guide plate 76. In addition to the above configuration,
The display elements 74 not including the optical waveguide plate 42 may be arranged in a matrix on the plate surface of the large light guide plate 76 to form the large screen display device 72.

The light guide plate 76 and the optical waveguide plate 42 are preferably similar in refractive index, and the light guide plate 76 and the optical waveguide plate 42 are preferable.
A transparent adhesive may be used when the and are bonded together. Like the optical waveguide plate 42 and the light guide plate 76, this adhesive preferably has a uniform and high transmittance in the visible light region, and has a refractive index close to that of the light guide plate 76 and the optical waveguide plate 42. It is desirable to set it to secure the brightness of the screen.

[0181] Also, the display device according to the embodiment, a structure of the actuator body 24 for selectively displacing the displacement-transmitting section 46, the vibration unit 16 pressure conductive layer 2 formed on the
Because it has to form a pair of electrodes 22a and 22b on one main side of 0, compared with the material (pressure conductive layer 20 of air or the displacement-transmitting section 46 between a pair of electrodes 22a and 22b dielectric constant Is very small). Therefore, the capacitance of the main actuator element 24 is pressure conductive layer 2
It becomes smaller than that in which electrodes are formed above and below 0, and accordingly, the CR time constant in signal transmission also becomes smaller. That is, the signal waveform of the voltage signal corresponding to the attribute of the image signal is less likely to be rounded.

[0182] Thus, it becomes possible to selectively applying a prescribed voltage to the pair of electrodes 22a and 22b in each pixel 12, it is possible to provide a stretch required for each pressure conductive layer 20, in particular, the voltage It is also possible to prevent the display brightness from being weakened in a portion (for example, the peripheral portion or the central portion of the screen) corresponding to the actuator portion 12 arranged at a position far from the portion to which the signal is supplied.

That is, in the display device according to the present embodiment, in addition to the advantage that the number of pixels does not need to be increased as compared with the case of a monochrome screen even when applied to a color display system, the actuator There is an advantage that the electrostatic capacitance in the portion 12 can be reduced, and when white is displayed on the entire display screen, uniform display brightness can be obtained, and image quality can be improved. .

Particularly, in the display device according to the present embodiment, as shown in FIGS. 4 and 5, one electrode 2 of the pair of electrodes 22a and 22b connected to the vertical selection line 48 is connected.
Since 2a has a pattern in which one row is connected in series, it becomes easy to increase the width of the outer peripheral portion of the one electrode 22a (shown by a broken line). In this case, the wiring resistance of the vertical selection line 48 can be reduced. The CR time constant in signal transmission can be further reduced.

Then, in the display device according to the present embodiment, as shown in FIGS.
Since the displacement direction of 2 is upward in the drawing (direction toward the optical waveguide plate 42 side), the displacement transmitting portion 46 can be pressed against the optical waveguide plate 42 by the displacement force of the actuator portion 12, and the optical waveguide Since the gap between the plate 42 and the actuator section 12 can be easily adjusted, it is advantageous to surely bring the displacement transmitting section 46 and the optical waveguide plate 42 into contact with each other.

[0186] In the display device according to this embodiment, for example, in the manufacturing process, when a part of the pressure conductive layer 20 is lost together with a part of the electrodes 22a and 22b thereon by dielectric breakdown or the like, pressure electrostatic Even if the layer 20 is not repaired, the electrodes 22a and 22b that have disappeared can be repaired sufficiently to function as the actuator portion 12. Therefore, it is possible to eliminate waste such as re-manufacturing the entire surface during the manufacturing process and to improve the yield of the display device. Can be achieved.

Further, in the display device according to the present embodiment, the vibrating portion 16 and the fixed portion 18 are integrally formed of the base body 10 (ceramics), and the concave portion 14 is formed at a position corresponding to the vibrating portion 16. Since the vibrating portion 16 is made thin, the fixed portion 18 and the vibrating portion 16 can be easily manufactured on the base body 10, which is advantageous in reducing the manufacturing cost of the display device.

The base 10 made of ceramics
For fixing portion 18 and the thin resonating section 16 of the thick by providing the concave portion 14 is shape that is formed, the vibrating unit 16 is sensitive to the elongation of the pressure conductive layer 20, to changes in voltage signal Therefore, the vibrating portion 16 having high followability can be obtained. Further, as compared with the actuator part having the double-supported structure or the cantilever structure, the rigidity of the boundary portion between the vibrating portion 16 and the fixed portion 18 is sufficiently ensured, so that the fatigue of the boundary portion due to the vibration of the vibrating portion 16 is caused. Destruction due to is less likely to occur. Further, since the substrate 10 and the vibrating portion 16 have high rigidity, the optical waveguide plate 42 and the driving portion 44 can be easily attached to each other.

[0189] In the display device according to this embodiment, a balanced shape of both corners of each plane shape of the recess 14 and the pressure conductive layer 20, further, pressure and size of the planar shape of the recess 14
Since it is made larger than that of the electric layer 20, the boundary portion between the vibrating portion 16 and the fixed portion 18 has an angular shape similar to the planar shape of the concave portion 14, and the stress generated by the vibration of the vibrating portion 16 is locally generated. No longer concentrates on the subject. Moreover, the entire periphery of the vibrating portion 16 is supported by the fixed portion 18,
The rigidity of the peripheral portion of the vibrating portion 16 can be increased. As a result, the fatigue limit at the boundary can be significantly improved, and the life of the actuator section 12 can be extended.
As a result, the life of the display device can be extended.

[0190] In the display device according to this embodiment, the planar shape of the on pressure conductive layer 20 of the pair of electrodes 22a and 22b, parallel pair of electrodes 22a and 22b are each other and spaced from each other due to the wiring shape spirally, when a predetermined voltage is applied to the pair of electrodes 22a and 22b, an electric field is generated radially (isotropically) on one main surface of the pressure conductive layer 20, therefore, pressure conductive layer 20,
Occurs radially extending in one main surface (surface) (isotropic), it occurs shrinkage radially (isotropically) at deep portions, thereby, pressure conductive layer 20 is efficiently so that its central portion is convex Therefore, the variation in displacement among the pixels 12 is reduced.

[0191] pressure electrodeposition of the pair of electrodes 22a and 22b
The planar shape of the on layer 20, in case of the multi-branched shape, when a predetermined voltage to the pair of electrodes 22a and 22b is applied, pressure conductive layer 20 is radially in one main surface (surface) (equal Since the expansion occurs in the (directional) direction and the contraction occurs in the deep part in the radial direction (isotropic), the center part is efficiently displaced so as to be convex, and the variation in displacement between the pixels 12 is small. Become.

In particular, the display device shown in FIG. 5 and FIG.
Since it divided into a stem 26 and 28 and the branches 30 and 32, as part of the pressure conductive layer 20, a portion corresponding to, for example, the branch portion 30 or 32 has disappeared with the branches 30 or 32 by dielectric breakdown or the like However, the influence exerted on others is very small, and as long as the trunk portions 26 and 28 remain, they will function sufficiently as the actuator portion 12. of course,
By simply repairing the lost electrode branch portion 26 or 28, the function before the disappearance can be restored, and the maintenance of the display device can be simplified.

In the display device according to the above-mentioned embodiment, as the optical waveguide plate 42, one having high flatness and smoothness on both sides is used, but in addition, so-called frosted glass whose rear surface is roughened is used. Is also possible. In this case, one main surface of the displacement transmitting portion 46 (the surface facing the back surface of the ground glass) is subjected to a rough surface treatment according to the rough surface shape on the back surface of the ground glass, or the one main surface portion of the displacement transmitting portion 46 is It is preferable to use an elastomer having a relatively low viscosity.

As a result, first, the light incident from the front is reflected by the rough surface of the frosted glass and is transmitted as scattered light in the front direction of the frosted glass. In this state, when a certain actuator portion 12 is excited and the displacement transmission portion 46 corresponding to the actuator portion 12 comes into contact with the rear surface of the ground glass, the rough surface of the contact portion causes the rough surface or the elasticity of the displacement transmission portion 46. Since the shape is canceled by the deformation, the light reflected by the rough surface portion of the ground glass up to that time is transmitted through the displacement transmitting portion 46 in contact with the back surface of the ground glass.

That is, even when ground glass is used as the optical waveguide plate 42, the displacement transmitting portion 46 on the back surface of the ground glass is used.
The presence or absence of light emission on the front surface of the frosted glass can be controlled by the presence or absence of the contact, and the same effect as that of the display device according to the above-described embodiment can be obtained. In particular, when frosted glass is used, the illuminating means for positively introducing light into the frosted glass is not required, and the configuration is simplified.

[0196] In this embodiment, an example of application to display device pressure Denmoto element according to the present invention, other filters, ultrasonic sensor or an angular velocity sensor or an acceleration sensor and various sensors impact sensor or the like, a microphone It can also be applied to sound generators (speakers, etc.), discriminators, oscillators or resonators for power or communication, servo displacement elements, pulse drive motors, ultrasonic motors, piezoelectric fans, etc. It can also be applied to actuators used.

[0197] Although the examples of applying the display device embodiment and the piezoelectric Denmoto child exemplary pressure Denmoto element according to the present invention have been specifically described, the present invention, the above described The present invention is not construed as being limited to the display devices according to the embodiments and examples, and various changes, modifications and improvements can be made without departing from the scope of the present invention.

[0198]

As described above, according to the present invention, pressure electrodeposition according to the present invention
According to element, a pressure conductive work moving unit and a pair of electrodes formed on one main surface of the pressure conductive layer and the piezoelectric layer, wherein the pressure conductive work in contact with the other main surface of the pressure conductive layer a vibrating section for supporting the moving portion, the fixing portion and the pressure Denmoto element provided with the unimorph pressure Denmoto element body having the vibratable supporting said vibrating section, a predetermined electric field between the pair of electrodes 4 displacement characteristics of the <br/> pressure Denmoto terminal body by more than double of the applied electric field, so that is asymmetrical about a reference electric field point.

Therefore, the relative displacement amount in the no-voltage state and the voltage applied state and the relative displacement amount in the state in which the electric fields in the opposite directions are applied can be greatly expanded, and the control when used as an actuator is easy. And the effect of being able to realize the improvement in sensitivity when used as a sensor.

[0200] Further, according to the pressure Denmoto element according to the present invention, pressure
A pressure conductive work moving unit having a conductive layer and the piezoelectric layer a pair of electrodes formed on one main surface of the pressure contact with the other main surface of the pressure conductive layer
A vibrating section for supporting the electric operation moving parts, the pressure Denmoto element having a unimorph pressure Denmoto element body having a fixing portion for vibratable supporting the vibrating portion, the distance between the pair of electrodes x (1μm ≦ x ≦ 200μm) , when the thickness of the pressure conductive layer was y (1μm ≦ y ≦ 100μm) , have a relationship of y = ax, and is set to 1/10 ≦ a ≦ 100.

[0201] Accordingly, the displacement characteristics of the pressure Denmoto element body by 4 times or more of an applied electric field of a predetermined electric field between the pair of electrodes can be asymmetrical about a reference electric field point, when used as an actuator The effect of being able to realize the easiness of control of and the improvement of sensitivity when used as a sensor is achieved.

[Brief description of drawings]

1 is a cross-sectional view showing the structure of a pressure Denmoto element according to the present embodiment.

[2] an actuator portion of the pressure Denmoto element according to the present embodiment is a sectional view showing a state where the displacement in one direction.

[3] The planar shape of the vibration part of an actuator body of the pressure Denmoto element according to the present embodiment, is a plan view showing a peripheral shape that is shaped in a planar shape and a pair of electrodes of the pressure conductive layer.

4 is a plan view showing a planar shape (spiral shape) of the pair of electrodes formed on the pressure conductive layer of pressure Denmoto element according to the present embodiment.

5 is a plan view showing a planar shape of a pair of electrodes (multivessel shape) formed in the pressure conductive layer of pressure Denmoto element according to the present embodiment.

[6] The case where the pressure conductive layer of the actuator unit in the display device according to this embodiment has a ring-shaped is a plan view schematically showing.

7 is a cross-sectional view taken along the line AA in FIG.

In the actuator unit in the display device 8 according to the present embodiment, the planar shape of the pressure conductive layer an annular, is a plan view showing an example in which a pair of electrodes and the multi-vessel shape.

[9] Figure 9A is a plan view showing a case where the outer peripheral shape of the ring-shaped pressure conductive layer with a circular, FIG. 9B is a ring-shaped pressure collector
It is a plan view showing a case where the outer peripheral shape of the layer is elliptical,
Figure 9C is a plan view showing a case where the outer peripheral shape of the ring-shaped pressure conductive layer and rectangular.

[10] Figure 10A is to measure a bending displacement characteristic of the pressure Denmoto element according to the present embodiment, a timing chart showing the potential waveform to be applied to the pair of electrodes, FIG. 10B is the embodiment it is a characteristic diagram showing the bending displacement characteristic of the pressure Denmoto element according to.

[11] Figure 11A is an explanatory view showing the polarization direction and electric field direction in the case of performing the initial polarization treatment against pressure conductive layer, FIG. 11B is a state (no-voltage-loaded stopping the voltage application to the pair of electrodes It is explanatory drawing which shows the polarization direction in (state).

[12] Figure 12A is an explanatory view showing the polarization direction and electric field direction of the state of applying an electric field (+ 3E) in the positive direction with respect to pressure Denmoto element according to the present embodiment, FIG. 12B is pressure Denmoto It is explanatory drawing which shows the polarization direction and electric field direction in the state which applied the predetermined negative electric field (-0.6E) with respect to a child.

[13] Figure 13A is an explanatory view showing the polarization direction and electric field direction of the state of applying an electric field (-3E) in the negative direction with respect to pressure Denmoto element according to the present embodiment, FIG. 13B is pressure electrostatic is an explanatory view showing the polarization direction and electric field direction of the state of applying the positive direction of the predetermined electric field (+ 0.6E) relative to element.

14 is a characteristic diagram showing the dimensional relationship between the thickness of the distance and the pressure conductive layer between a pair of electrodes in pressure Denmoto element according to the present embodiment.

FIG. 15A is an explanatory diagram showing an inter-electrode distance when a pair of electrodes has a spiral planar shape;
FIG. 6 is an explanatory diagram showing an inter-electrode distance when the planar shape of a pair of electrodes is a multi-branched shape.

FIG. 16 is a characteristic diagram showing the dimensional relationship between the thickness of the thickness and pressure conductive layer of the vibrating portion in the pressure Denmoto element according to the present embodiment.

FIG. 17A is a cross-sectional view with a part of the cross-sectional shape of the actuator section at the shortest dimension omitted, and FIG. 17B shows one outermost minimum point and the other outermost minimum point from the upper surface of the fixed section. FIG. 17C is a cross-sectional view partially omitting the case where it exists below, and FIG. 17C partially omits the case where one outermost minimum point and the other outermost minimum point exist above the upper surface of the fixed portion. FIG.

FIG. 18A omits a part of an example of a case where the other outermost minimum point does not exist in the other minimum point existence region and the other boundary point is recognized as the other outermost minimum point. FIG. 18B is a cross-sectional view showing that there is no outermost minimum point in both minimum point existence regions, and one boundary point and the other boundary point are one outermost minimum point and the other outermost minimum point, respectively. It is sectional drawing which abbreviate | omits a part and shows the example at the time of being recognized as a point.

FIG. 19 is a plan view showing a preferred example in which the pair of electrodes has a comb-shaped planar shape.

[20] Example of application to display device pressure Denmoto element according to the present embodiment (hereinafter, simply referred to as a display device according to the embodiment) is a diagram showing a.

FIG. 21 is an enlarged plan view showing an arrangement of actuator portions (pixels) in the display device according to the present embodiment.

[22] display device according to this embodiment, in particular the vibrating unit, pressure electrostatic
It is a top view which shows the planar shape (ellipse shape, spiral shape) of a layer and a pair of electrodes.

[23] display device according to this embodiment, in particular the vibrating unit, pressure electrostatic
It is a top view which shows the planar shape (ellipse shape, multi-branch shape) of a layer and a pair of electrodes.

FIG. 24 is an enlarged plan view showing another example of the arrangement of the actuator parts (pixels) in the display device according to the present embodiment.

FIG. 25 is a display device according to the present embodiment, particularly a vibrating part and a pressure device.
It is a top view which shows an electric layer (rectangular shape).

FIG. 26 is a display device according to the present embodiment, particularly a vibrating section and a pressure display.
It is a top view which shows an electric layer (octagonal shape).

FIG. 27A is a timing chart showing changes in voltage level in a non-selected state and an ON selected state in the actuator section, and FIG. 27B shows changes in voltage level in a non-selected state and an OFF selection state in the actuator section. It is a timing chart shown.

28A is a timing chart in the case where the ratio of the emission time of RGB is 1: 1: 1 when the display device according to the present embodiment is applied to a color display system, and FIG. It is a timing chart when the ratio of the light emission time is 4: 1: 5.

FIG. 29 is a perspective view showing a large-screen display device by the display device according to the present embodiment as viewed from the back side.

Figure 30 is a sectional view showing a pressure Denmoto element according to a conventional example.

[31] Figure 31A is to measure a bending displacement characteristic of the pressure Denmoto element according to the conventional example, is a timing chart showing the potential waveform to be applied to the upper and lower electrodes, FIG. 31
B is a characteristic diagram showing the bending displacement characteristic of the pressure Denmoto element according to a conventional example.

[32] Figure 32A is an explanatory view showing the polarization direction and electric field direction in a state where the forward direction by multiplying the electric field (+ 3E) against pressure Denmoto element according to the conventional example, in Figure 32B pressure Denmoto child It is explanatory drawing which shows the polarization direction and electric field direction in the state which applied the negative predetermined electric field (-0.5E) with respect to it.

[33] Figure 33A is an explanatory view showing the polarization direction and electric field direction of the state of applying an electric field (-3E) in the negative direction with respect to pressure Denmoto element according to the conventional example, FIG. 33B is pressure Denmoto child FIG. 7 is an explanatory diagram showing a polarization direction and an electric field direction in a state where a predetermined electric field (+ 0.5E) in the positive direction is applied to.

[Explanation of symbols]

10 ... correction contents in the range of the base body 12 ... actuator 14 ... recess 16 ... vibrating portion 18 ... fixing portion 20 ... pressure conductive layer 22a, 22b ... a pair of electrodes 24 ... actuator body of this patent claims, 200
It is the same as the content sent by FAX on December 24, 3rd.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI H01L 41/22 Z (56) Reference JP-A-5-347439 (JP, A) JP-A-8-114408 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 41/09 H01L 41/22

Claims (11)

(57) [Claims] 1. A and pressure conductive layer, and a pressure conductive work moving unit and a pair of electrodes formed only on one main surface of the piezoelectric layer, wherein the pressure conductive contact with the other main surface of the pressure conductive layer a vibrating section for supporting the work moving unit, the fixing portion and the pressure Denmoto element provided with the unimorph pressure Denmoto element body having the vibratable supporting the vibrating portion, the piezoelectric layer, at least the pair of Before between electrodes
In the surface portion on the one main surface side of the piezoelectric layer, a flat surface is formed on the one main surface.
Is polarized in the running direction, and the polarization includes inversion
There, the surface of one principal surface of the piezoelectric layer to between the pair of electrodes
A mark of 4 times or more of the electric field at which the polarization in the part begins to reverse
Field of the pressure Denmoto element body by pressurizing field - bending displacement characteristic, <br/> pressure Denmoto element, characterized in that the asymmetric about a reference electric field point. 2. The method of claim 1, wherein the pressure Denmoto child, the polarization is inverted at the surface portion of one principal surface of the piezoelectric layer
When the start field is defined as a predetermined electric field, the reference electric field point as a reference, the amount of displacement upon application of each of the four or more times the electric field of the absolute value of the direction with the same two different predetermined field A, and B when, pressure Denmoto element characterized by having a relationship of a ≧ 1.5B. 3. A pressure conductive layer, and a pressure conductive work moving unit and a pair of electrodes formed only on one main surface of the piezoelectric layer, wherein the pressure conductive contact with the other main surface of the pressure conductive layer comprising a vibrating section for supporting the work moving unit, a unimorph pressure Denmoto element body having a fixing portion for vibratable supporting the vibrating portion, the piezoelectric layer is pre respect between at least the pair of electrodes
In the surface portion on the one main surface side of the piezoelectric layer, a flat surface is formed on the one main surface.
Is polarized in the running direction, and the polarization includes inversion
There, the distance between the pair of electrodes x (1μm ≦ x ≦ 200μ
m), the thickness of the pressure conductive layer y (1μm ≦ y ≦ 100μ
m), there is a relationship of y = ax, and 1/10 ≦ a ≦ 100
Denmoto child. 4. A pressure electrodeposition according to any one of claims 1 to 3
In element, pressure the vibrating section and the fixed portion are integrally formed by ceramics, is void is formed at positions corresponding to the vibration part, the vibration unit is characterized in that it is thinner Denmoto child. 5. The method of Claim 3 or 4, wherein the pressure Denmoto child, pressure Denmoto element, which is a 1/5 ≦ a ≦ 10. 6. The pressure according to claim 5.Electric elementIn the child, 1/2 ≦ a ≦ 5 and 1 μm ≦ x ≦ 60 μm,
Pressure characterized by 1 μm ≦ y ≦ 40 μmElectric element
Child. 7. A pressure electrodeposition according to any one of claims 3-6
In element, the thickness of the vibrating section when the z (1μm ≦ z ≦ 50μm) , have a relationship of y = bz, and, 1/5 ≦ b ≦ 10
Pressure Denmoto child, characterized in that it. 8. The system of claim 7, wherein the pressure Denmoto child, pressure Denmoto element, which is a 1/3 ≦ b ≦ 5. 9. The pressure according to claim 8.Electric elementIn the child, 1/3 ≦ b ≦ 5 and 1 μm ≦ y ≦ 40 μm,
Pressure characterized in that 1 μm ≦ z ≦ 20 μmElectric element
Child. 10. The pressure according to any one of claims 4 to 9.
In Denmoto child, the cross-sectional shape in the shortest dimension passing through the center of the vibrating portion,
Pressure Denmoto child that satisfies the following conditions at no-voltage-loaded state. (1) wherein the fixed outermost local minimum point of one adjacent to the portion and the other of the reference line formed by connecting the outermost local minimum point, at least a portion of the upper surface in the central portion near the pressure conductive layer, wherein It protrudes in the direction opposite to the vibrating part. (2) If the outermost local minimum point does not exist, the point corresponding to the boundary point with the fixed portion on the upper surface of the vibrating portion along the shortest dimension should be the outermost local minimum point. (3) When the boundary part of the vibrating part with the fixed part is 0 point and the shortest dimension length of the vibrating part is 100, the outermost local minimum point is the shortest dimension length of the vibrating part from the 0 point. If it is not within the range of 40%, the point on the upper surface of the vibrating portion along the shortest dimension that corresponds to the boundary point with the fixed portion should be the outermost minimum point. 11. A pressure Denmoto terminal of claim 10, put the shortest dimension passing through the center of the vibration part m, the (1)
When the above-mentioned protruding amount is t, m / 1000 ≦ t ≦
pressure Denmoto child, which is a m / 10.