KR20190050035A - Display apparatus - Google Patents

Abstract

An embodiment of the present invention relates to a display apparatus which comprises: a display panel; first to N^th piezoelectric actuators arranged to be separated from each other on a rear surface of the display panel and vibrating the display panel in response to each of first to N^th driving signals, wherein N is an integer higher than or equal to two; and a driving signal generation unit for generating and outputting at least one of the first to N^th driving signals having different frequencies by vibration modes. The vibration modes include at least two among a first vibration mode for vibrating a part of a plurality of piezoelectric actuators, a second vibration mode for simultaneously vibrating the plurality of piezoelectric actuators, and a third vibration mode for vibrating the plurality of piezoelectric actuators with a time difference.

Description

[0001]

An embodiment relates to a display device.

Electronic devices such as cellular phones, portable media players, tablet computers, laptops, laptops, personal computers, cash registers, electronic book readers, input devices, etc. have built-in speakers for sound output, And has a haptic function. The haptic function is a function of generating various tactile effects that the user can feel by providing vibration to the user.

These loudspeakers are built in separate module-shaped actuators at the top, bottom, or sides of the device to produce sound, and separate actuators are provided to provide haptic functionality to provide physical vibrations to the panel.

Such an actuator has different characteristics depending on its function, and the position to be disposed also depends on the function. In the case of a smart phone, a receiver for a call is disposed at the top of the display area, a speaker for sound output is disposed at a different position other than a position at which the receiver is disposed, and an actuator for haptic function is also disposed at a separate position. Thus, each actuator occupies a certain space inside the electronic device, making it difficult to place the display area in front of the electronic device. There is thus a growing need to integrate actuators that provide sound and vibration to the display.

The embodiment provides a display device capable of providing various complex vibration modes.

A display device according to an embodiment includes a display panel; First to Nth piezoelectric actuators disposed on a rear surface of the display panel, the first to Nth piezoelectric actuators vibrating the display panel in response to driving signals of first to Nth (where N is a positive integer of 2 or more) driving signals; And a drive signal generator for generating and outputting at least one of the first to N-th drive signals having different frequencies for each vibration mode, wherein the vibration mode includes: a first vibration mode for vibrating a part of the plurality of piezoelectric actuators; A second vibration mode for simultaneously vibrating the plurality of piezoelectric actuators; Or a third vibration mode in which the plurality of piezoelectric actuators are oscillated with a parallax therebetween.

For example, each of the first through Nth piezoelectric actuators may be smaller than a first distance spaced from a center of the back surface of the display panel, the second distance being spaced from an edge of the back surface.

For example, the first to Nth piezoelectric actuators may have a cross-section and a planar shape symmetrically arranged with respect to a central axis of the display panel.

For example, the driving signal generator may include a main controller for determining the vibration mode and outputting the determined result as an event signal; An auxiliary controller for determining at least one frequency among the first through N-th driving data according to the event signal and outputting at least one of first or Nth driving data having a determined frequency; First to Nth digital-analog converters for respectively converting the first to N-th driving data in digital form into analog form and outputting the analog data; And first to Nth amplifying units for amplifying the outputs of the first to Nth digital / analog converting units and outputting the amplified result as the first to Nth driving signals, respectively.

For example, the drive signal generator may determine the vibration mode, determine at least one frequency of the first to Nth drive data according to the determined result, and determine at least one of the first to N < th & A main control unit for outputting the main control signal; First to Nth digital-analog converters for respectively converting the first to N-th driving data in digital form into analog form and outputting the analog data; And first to Nth amplifying units for amplifying the outputs of the first to Nth digital / analog converting units and outputting the amplified result as the first to Nth driving signals, respectively.

For example, the driving signal generator may include a main controller for determining the vibration mode and outputting the determined result as an event signal; A digital / analog converter for converting the digital event signal into an analog form; And an active amplifier unit for determining at least one of the first through N-th driving signals according to the analog event signal and for amplifying and outputting at least one of the first through N-th driving signals having the determined frequency .

For example, when the vibration mode is the third vibration mode, the active amplification unit adds touch information to the analog type event signal, and when the vibration mode is not the third vibration mode, A touch information generating unit for bypassing the touch information; A source portion for outputting at least one of the first to N-th driving signals having a frequency determined according to the bypassed event signal or the event signal to which the touch information is added; And first to N-th amplifiers for amplifying and outputting at least one of the first to N-th driving signals output from the source unit.

For example, the touch information includes coordinates of a touched position; Or a touch strength.

For example, the drive signal generator may generate an n-th (1? N? N) drive signal having a first frequency belonging to the first frequency band in the first vibration mode and output the drive signal to the n-th piezoelectric actuator .

For example, the drive signal generator may generate first to Nth drive signals having a second frequency, each of which belongs to the second frequency band and is smaller than the first frequency, in the second vibration mode.

For example, the drive signal generator may generate first to Nth drive signals each having a third frequency that is lower than the second frequency in the third frequency band in the third vibration mode.

The display device according to the embodiment may provide at least two modes of the speaker mode, the receiver mode, and the haptic mode through the display panel. It is also possible to integrate various vibration modes in the display panel, thereby eliminating the separate sound output space and increasing the area occupied by the display in the electronic device.

In addition, it is possible to accurately control various complex vibration modes by using a plurality of actuators.

FIG. 1A is an assembled sectional view of a display panel according to an embodiment, and FIG. 1B is an exploded sectional view of the display panel 100 shown in FIG. 1A.
FIG. 2A is an exploded perspective view of a piezoelectric element embodying each of the first and second piezoelectric actuators shown in FIGS. 1A and 1B, and FIG. 2B is an exploded perspective view of the piezo-electric part and the internal electrode shown in FIG. FIG. 2C is a plan view of the piezoelectric portion and the internal electrode shown in FIG. 2A according to an embodiment of the present invention. FIG.
FIG. 3 shows a block diagram of an embodiment of the drive signal generator shown in FIG. 1A.
FIG. 4 shows a block diagram of another embodiment of the drive signal generator shown in FIG. 1A.
Fig. 5 shows a block diagram of another embodiment of the drive signal generator shown in Fig. 1A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to facilitate understanding of the present invention. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the invention are provided to more fully describe the present invention to those skilled in the art.

In the description of the present embodiment, in the case of being described as being formed "on or under" of each element, the upper (upper) or lower (lower) on or under includes both the two elements being directly in contact with each other or one or more other elements being indirectly formed between the two elements.

Also, when expressed as "on" or "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

It is also to be understood that the terms "first" and "second," "upper / upper / upper," and "lower / lower / lower" But may be used to distinguish one entity or element from another entity or element, without necessarily requiring or implying an order.

Hereinafter, a display device 100 according to an embodiment will be described with reference to the accompanying drawings. For convenience, the display device 100 is described using a Cartesian coordinate system (x-axis, y-axis, z-axis), but it is obvious that other coordinate systems can explain this. Further, according to the Cartesian coordinate system, the x-axis, the y-axis and the z-axis are orthogonal to each other, but they may intersect without being orthogonal.

FIG. 1A is an assembled cross-sectional view of a display panel 100 according to an embodiment, and FIG. 1B is an exploded cross-sectional view of a display panel 100 shown in FIG. 1A. For convenience, the illustration of the drive signal generator 130 in FIG. 1B has been omitted.

1A and 1B, a display device 100 includes a display panel 110, first through Nth piezoelectric actuators 120-1 through 120-N, a driving signal generating unit 130, . ≪ / RTI > Here, N is a positive integer of 2 or more.

Hereinafter, the case where the number of channels N is '2' will be described for convenience of explanation, but the following explanation can also be applied when N is 3 or more.

The display panel 110 may be disposed over the frame 140. The display panel 110 and the frame 140 may be coupled to each other in a fit manner, although not shown in FIGS. 1A and 1B, by a first adhesive layer 152, as shown in FIGS. 1A and 1B, The panel 110 may be bonded to the frame 140 and embodiments are not limited to the particular combination of the display panel 110 and the frame 140.

In addition, the display panel 110 may include a display layer 112 and a cover member 114.

The display layer 112 is disposed under the cover member 114 and the first and second piezoelectric actuators 120-1 and 120-2 may be disposed on the lower surface of the cover member 114. [ Display layer 112 may be an organic electroluminescent display (OLED) panel substrate or a plastic OLED panel substrate. In this case, the display layer 112 may include a self-luminous element not requiring a separate light source. Alternatively, the display layer 112 may comprise a thin film transistor (TFT). However, the embodiment is not limited to the particular structure or material of the display layer 112.

The cover member 114 may be disposed over the display layer 112. The cover member 114 may be rigid or flexible. Preferably, the cover member 114 may be flexible to be foldable or bending. The display layer 112 may have a smaller area than the cover member 114.

For example, the cover member 114 may include plastic or glass. In detail, the cover member 114 may include reinforced or soft plastic such as polyimide (PI), polyethylene terephthalate (PET), propylene glycol (PPG), polycarbonate (PC) . ≪ / RTI >

In addition, the cover member 114 may include an optically isotropic film. For example, the cover member 114 may include a Cyclic Olefin Copolymer (COC), a Cyclic Olefin Polymer (COP), a polycarbonate (PC), a light polymethyl methacrylate (PMMA), or the like.

Further, although not shown, the display panel 110 may further include a metal layer. The metal layer may be disposed under the display layer 112 and may be formed of aluminum (Al).

Meanwhile, the frame 140 supports the display panel 110 and can be divided into an inner part (IP) and an outer part (OP). At this time, the outer side OP is protruded with a higher sectional shape with respect to the inner side IP.

For example, when the display device 100 according to the embodiment is applied to a flat-type smartphone, four (four) pieces of the display device 100 in the frame 140 having a square-planar shape (e.g., a rectangular shape, a square shape or a round- And the outer side OP of the adjacent side may be all protruding.

Alternatively, in the frame 140 having a rectangular planar shape, only the outer side OP near two sides facing each other among the four side outer sides OP may be protruded. For example, only the outer side OP near the upper and lower sides facing each other protrudes and the outer side OP near the left side and the right side may not protrude. Alternatively, only the outer side OP opposed to the left side and the right side opposed to each other may protrude, and the outer side OP near the upper side and the lower side may not protrude.

A display panel 110 is disposed on the upper part of the frame 140 and a wiring (not shown) or a printed circuit board (not shown) connected to the display panel 110 may be disposed under the frame 140.

In addition, the frame 140 may correspond to the housing itself constituting the appearance of the display device 100.

For example, the frame 140 may include all parts except the display panel 110, the first and second piezoelectric actuators 120-1 and 120-2, and the drive signal generating part 130 in the display device 100 . As such, the frame 140 may correspond to a mechanical part in the display device 100. [ However, the embodiment is not limited to any particular form of frame 140. In addition, the module may be a remaining part of the display device 100 excluding a mechanical part, for example, the frame 140. [ Thus, the display device 100 may include a frame 140 and a module.

The first adhesive layer 152 may be disposed between the display panel 110 and the frame 140 to adhere the display panel 110 to the edge portion of the inner portion IP of the frame 140. For example, a first adhesive layer 152 may be disposed between the display layer 112 and the frame 140 to adhere the display layer 112 to the edge portion of the interior (IP) of the frame 140 . In addition, the first adhesive layer 152 may be adhered to the back surface 110B of the display panel 110 in various forms.

Also, the first adhesive layer 152 may include a silicon-based material, and may be, for example, a silicone-based epoxy. The first elastic modulus of the first adhesive layer 152 may be 1 MPa to 25000 MPa, preferably 100 MPa to 10000 MPa, more preferably 50 MPa to 2000 MPa, but the embodiment is not limited thereto.

If the thickness of the first adhesive layer 152 is less than 30 μm, the vibration force of the display panel 110 may be deteriorated. In addition, when the thickness of the first adhesive layer 152 is larger than 150 m, the display device 100 can not be made thin. Therefore, the thickness of the first adhesive layer 152 may be 30 [mu] m to 150 [mu] m, but the embodiment is not limited thereto.

The first and second piezoelectric actuators 120-1 and 120-2 are disposed on the rear surface 110B of the display panel 110 so as to be spaced apart from each other. By disposing the first and second piezoelectric actuators 120-1 and 120-2 in this manner, it is possible to remove a separate receiver hole or speaker hole by adopting a method of outputting sound by vibrating the display panel 100 .

The first and second piezoelectric actuators 120-1 and 120-2 operate in response to the first and second drive signals, respectively. The display panel 114 can vibrate by operating the first piezoelectric actuator 120-1 in response to the first drive signal. The first and second piezoelectric actuators 120-1 and 120-2 can vibrate in the horizontal direction (e.g., the y-axis direction) in response to an electrical signal. In this way, when at least one of the first and second piezoelectric actuators 120-1 and 120-2 vibrates in the horizontal direction, the display panel 110 vibrates in the vertical direction (e.g., the z-axis direction) .

The first and second piezoelectric actuators 120-1 and 120-2 and the back surface 110B of the display panel 110 can be coupled by the second adhesive layer 154. [ That is, the second adhesive layer 154 serves to adhere the first and second piezoelectric actuators 120-1 and 120-2 to the back surface 110A of the display panel 110, and has a second elastic modulus . The second adhesive layer 154 may be disposed on the rear surface 110B of the display panel 110 in various forms.

In order to lower the resonance frequency fo of the entire module including the display panel 110 and the first and second piezoelectric actuators 120-1 and 120-2, the second elastic modulus of the second adhesive layer 154 is low . For example, the second elastic modulus may be 1 MPa to 25000 MPa, preferably 100 MPa to 10000 MPa, more preferably 200 MPa to 4000 MPa, although the examples are not limited thereto.

When the second adhesive layer 154 has such a second modulus of elasticity, the resonance frequency fo of 1 kHz can be lowered to 200 Hz to 300 Hz. Thus, the resonance frequency fo can be lowered by raising the total mass increase rate of the second adhesive layer 154 with respect to the second elastic modulus. The second adhesive layer 154 may have a second modulus of elasticity greater than the first modulus of elasticity.

In addition, the second adhesive layer 154 may be embodied as an adhesive epoxy and may have a thickness of from 2 占 퐉 to 20 占 퐉, but the embodiments are not limited thereto.

The first piezoelectric actuator 120-1 is arranged on the rear side of the display panel 110 in a horizontal direction (e.g., the y-axis direction) The second distance D12 may be smaller in the horizontal direction (e.g., the y-axis direction) from the edge E of the light source 110B. The second piezoelectric actuator 120-2 is disposed on the back side of the display panel 110 in a horizontal direction (e.g., the y-axis direction) from the center C of the back surface 110B of the display panel 110, The second distance D22 may be smaller in the horizontal direction (e.g., the y-axis direction) from the edge E of the light source 110B. Thus, each of the first and second piezoelectric actuators 120-1 and 120-2 can be disposed closer to the edge E than the center C of the back surface 110B. The first and second piezoelectric actuators 120-1 and 120-2 are arranged closer to the center C than the edge E of the back surface 110B in consideration of the mode shape The restoration time when the vibrating display panel 110 returns to its original state is shorter than that when the vibrating display panel 110 is restored, and the energy for vibrating the display panel 110 can be lowered.

The first and second piezoelectric actuators 120-1 and 120-2 may have a cross sectional shape symmetrically arranged with respect to the center axis CX of the display panel 110. [ Also, although not shown, the first and second piezoelectric actuators 120-1 and 120-2 may have a planar shape symmetrically arranged with respect to the center axis CX of the display panel 110 .

For example, each of the first and second piezoelectric actuators 120-1 and 120-2 may include a piezoelectric element, and the piezoelectric element may be formed of a piezoelectric ceramic, a piezoelectric single crystal, a PVDF, or the like.

The reason why the piezoelectric element can be used as each of the first and second piezoelectric actuators 120-1 and 120-2 is that when the display device 100 is applied to a cellular phone with a narrow internal space, .

In addition, vibration characteristics (particularly in the low frequency range) of the piezoelectric element may be worse than that of a voice coil motor (VCM). The display device 100 according to the embodiment can solve this problem by using the first and second adhesive layers 152 and 154.

Hereinafter, an embodiment 120A of the piezoelectric element implementing each of the first and second piezoelectric actuators 120-1 and 120-2 will be described with reference to FIGS. 2A to 2C, Is not limited to this. That is, each of the first and second piezoelectric actuators 120-1 and 120-2 may be realized as a piezoelectric element other than the piezoelectric element shown in Figs. 2A to 2C.

2A shows an exploded perspective view of a piezoelectric element 120A embodying each of the first and second piezoelectric actuators 120-1 and 120-2 shown in Figs. 1A and 1B, and Fig. 2B is a cross- 2A shows an external perspective view of the piezoelectric unit 122 and the internal electrode 121 shown in FIG. 2A. FIG. 2C is a perspective view of the piezoelectric unit 122 and the internal electrode 121 shown in FIG. Fig.

2A to 2C, a piezoelectric element 120A according to an embodiment includes an internal electrode 121, a piezoelectric portion 122, an external electrode 126, and a passivation layer 128 .

The piezoelectric element 120A according to the embodiment can operate as a kind of speaker for converting an electrical signal into an acoustic signal. In addition, the piezoelectric element 120A according to the embodiment may operate as a kind of microswitch for converting an acoustic signal into an electrical signal.

The piezoelectric portion 122 may be in the form of a plate having a height (or thickness) H, a width W and a longitudinal width L (or length) L, but the embodiment is not limited to the specific shape of the piezoelectric portion 122 It is not limited. Here, the lateral width W may be greater than the height H and the longitudinal width L may be greater than the lateral width W. [

The piezoelectric unit 122 may include M unit blocks and M-1 third adhesive layers 124. Here, M may be a positive integer of 2 or more.

Hereinafter, the case where M = 4 as shown in FIGS. 2A to 2C will be described as the piezoelectric element 120A according to the embodiment, but the following description can also be applied to a case where M is smaller or larger than 4. 2C shows only a part of the first to fourth unit blocks B1 to B4 for convenience of explanation.

The first to fourth unit blocks B1 to B4 are stacked in the polarization direction. Here, the polarization direction coincides with the direction in which the internal electrodes 121 are arranged as the direction in which the polarization occurs. In addition, the polarization direction may be the longitudinal axis direction (e.g., the y-axis direction) of the piezoelectric portion 122.

Each of the first to fourth unit blocks B1 to B4 includes an internal electrode 121 and may include a ceramic piezoelectric material. The ceramic piezoelectric material may be a single crystal or a polycrystal. For example, single crystal ceramic-based piezoelectric material _{PZN-PT [Pb (Zn 2/3} Nb 1/3) O 3 -PbTiO 3] or _{PMN-PT [Pb (Mg 2/3} Nb 1/3) O 3 - PbTiO ₃ ]. Alternatively, the polycrystalline ceramic piezoelectric material may include a Pb-based or non-Pb-based basic composition. For example, the polycrystalline ceramic piezoelectric material having a Pb-based basic composition may include at least one of Pb (Zr, Ti) O ₃ or PZT (Pb Zirconate Titanate). Alternatively, the polycrystalline ceramic piezoelectric material having a non-Pb-based basic composition may include at least one of K _0.5 Na _0.5 NbO ₃ or KNN.

However, the material of the first to fourth unit blocks B1 to B4 is not limited to the ceramic-based piezoelectric material. That is, if stacking is possible, slicing can be performed, and internal electrodes IE1, IE2, DE1 to DE4 can be deposited or printed, the material of the first to fourth unit blocks B1 to B4 is a specific type of piezoelectric It is not limited to materials. For example, the internal electrodes IE1, IE2, and DE1 to DE4 may be formed by printing using a screen printing technique.

According to another embodiment, the material of the first to fourth unit blocks B1 to B4 may be a polymer-based piezoelectric material.

The third adhesive layer 124 is disposed between the plurality of unit blocks B1 to B4 and serves to adhere them to each other. As described above, when N = 4, the piezoelectric portion 122 may include three third adhesive layers 124 (A11, A12, A13). The third-first adhesive layer A11 serves to bond the first and second unit blocks B1 and B2 adjacent to each other, and the third-second adhesive layer A12 serves to adhere the second and third unit blocks A12, B2 and B3, and the third-third adhesive layer A13 serves to bond the third and fourth unit blocks B3 and B4 adjacent to each other.

Further, the third adhesive layer 124 may include an epoxy based adhesive material, but the embodiment is not limited to the specific constituent material of the third adhesive layer 124.

In addition, when the elastic modulus of the third adhesive layer 124 is lowered, the resonance frequency fo of the piezoelectric element 120A can be lowered. If the elastic modulus of the third adhesive layer 124 is less than 1 MPa, the inherent physical properties of the third adhesive layer 124 may be deteriorated and the adhesive force may be weak. Therefore, the modulus of elasticity of the third adhesive layer 124 may be 1 MPa or more. For example, the third modulus of elasticity of the third adhesive layer 124 may be from 1 MPa to 25000 MPa, preferably from 100 MPa to 10000 MPa, more preferably from 200 MPa to 4000 MPa, Do not. Thus, when the third elastic modulus of the third adhesive layer 124 is adjusted, the resonance frequency fo of the piezoelectric element 120A can be lowered, for example, from 1 kHz to 200 Hz to 300 Hz. This is a principle that raises the total mass increase rate relative to the total modulus of elasticity and lowers the resonance frequency fo.

On the other hand, the internal electrode 121 may be disposed inside the piezoelectric portion 122.

According to one embodiment, the internal electrode 121 may include first and second internal electrodes IE1 and IE2.

In addition, the number of internal electrodes 121 included in each of the plurality of unit blocks B 1 to B 4 may be the same or different from each other. For example, in the case of FIGS. 2B and 2C, the number of the internal electrodes 121 included in each of the first to fourth unit blocks B1 to B4 may be six and the same. For example, the second unit block B2 may include three first internal electrodes IE1 (IE211, IE212, IE213) and three second internal electrodes IE2 (IE221, IE222, IE223). Each of the first and third unit blocks B1 and B3 may include three first internal electrodes IE1 and three second internal electrodes IE2 as the second unit block B2.

In the unit blocks B1 to B4, the first and second internal electrodes IE1 and IE2 are spaced apart from each other in the longitudinal direction (e.g., the y-axis direction) of the piezoelectric portion 122, As shown in FIG. For example, referring to FIG. 2C, the first internal electrodes IE1 (IE211, IE212, IE213) and the second internal electrodes IE2 (IE221, IE222, IE223) And are repeatedly arranged mutually alternately.

The lengths (x1, x2) in the transverse direction (e.g., the x-axis direction) of the first internal electrodes (IE1: IE211, IE212, IE213) and the second internal electrodes (IE2: IE221, IE222, IE223) (For example, the x-axis direction) of the piezoelectric portion 122. The width W of the piezoelectric portion 122 may be smaller than the width W of the piezoelectric portion 122 in the x-axis direction.

The side surface of the piezoelectric portion 122 is a surface defined by the height H and the longitudinal width L and may include one side surface S1 and the other side surface S2 opposite to each other.

The grooves may be disposed symmetrically with respect to one side surface S1 and the other side surface S2 of the piezoelectric portion 122. [ Although the groove HO is formed only on one side S1 in the case of FIG. 2B, it may be symmetrically formed on the other side S2.

The first internal electrode IE1 (IE211, IE212, IE213) may be exposed to one side S1 of the piezoelectric portion 122 and electrically connected to the first external electrode 126-2. The second internal electrode IE2 (IE221, IE222, IE223) may be exposed to the other side S2 of the piezoelectric portion 122 and electrically connected to the second external electrode 126-1.

The first internal electrode IE1 may be a positive electrode and the second internal electrode IE2 may be a negative electrode. Alternatively, the first internal electrode IE1 may be a negative (-) electrode and the second internal electrode IE2 may be a positive (+) electrode.

The external electrode 126 is disposed on the side surfaces S1 and S2 of the piezoelectric portion 122 and may include first and second external electrodes 126-2 and 126-1. The first external electrode 126-2 may be disposed on one side S1 of the side surface of the piezoelectric portion 122 and connected to the first internal electrode IE1. The second external electrode 126-1 may be disposed on the other side S2 of the side surface of the piezoelectric portion 122 and connected to the second internal electrode IE2.

The first internal electrode IE1 included in each of the plurality of unit blocks B1 to B4 is electrically connected in common to one first external electrode 126-2 and the plurality of unit blocks B1 to B4 The second internal electrode IE2 included in the second external electrode 126-1 may be electrically connected in common to one second external electrode 126-1.

In addition, each of the first to fourth unit blocks B1 to B4 may include a dummy area (DA) and a polarization area (PA).

The dummy portion DA can be defined as an area between the third adhesive layer 124 and the inner electrode closest to the third adhesive layer 124 of the inner electrode 121 in each of the unit blocks B1 to B4. For example, assuming that six internal electrodes (IE211 to IE213, IE221 to IE223) are arranged in the second unit block B2 as shown in Fig. 2C, six internal electrodes (IE211 to IE213, IE221 The region between the internal electrode IE223 and the third adhesive layer A12 may correspond to the dummy portion DA since the internal electrode IE223 is disposed closest to the third adhesive layer A12.

Further, the polarized portion PA can be defined as an area between the first and second internal electrodes IE1 and IE2. For example, referring to FIG. 2C, a region between the first internal electrode IE 213 and the second internal electrode IE 223 may correspond to the polarization unit PA.

Further, no polarization occurs in each of the third adhesive layers 124 (A11 to A13) and the dummy portion DA, and polarization occurs only in the polarized portion PA. Therefore, in order to reduce a portion where polarization does not occur in the entire vertical width L of the piezoelectric portion 122 in the longitudinal direction (for example, the y-axis direction) It is preferable that the first length y1 of the adhesive layer 124 (A11 through A13) and the second length y2 of the dummy portion DA be shorter.

It is preferable that the dummy portion DA be present because the dummy portion DA can increase the mass increase rate relative to the mechanical stress and the elastic coefficient after the polarization of the piezoelectric element 120A to lower the resonance frequency fo. That is, the second length y2 may be greater than zero.

The first length y1 of the third adhesive layer 124 (A11 to A13) may be smaller than the third length y3 of the polarized portion PA in the longitudinal direction (e.g., the y-axis direction). This is because when the first length y1 of the third adhesive layer 124 (A11 to A13) is large, the weight of the piezoelectric element 120A increases and the vibration force can be attenuated. The second length y2 of the dummy portion DA may be smaller than the third length y3 of the polarized portion PA in the longitudinal direction (e.g., the y-axis direction).

For example, the first length y1 of the third adhesive layer 124 (A11 to A13) in the longitudinal direction (e.g., the y-axis direction) may be 0 to 20 占 퐉, preferably 2 占 퐉 to 10 占 퐉 . For example, the second length y2 of the dummy portion DA in the longitudinal direction (e.g., the y-axis direction) is greater than 0 and less than 50 占 퐉, preferably 10 占 퐉 to 50 占 퐉, more preferably 30 Mu m or 40 mu m. For example, the third length y3 of the polarizing portion PA in the longitudinal direction (e.g., the y-axis direction) may be 20 [mu] m to 100 [mu] m. However, the embodiment is not limited to specific values of the first to third lengths (y1, y2, y3).

Referring again to FIG. 1A, the drive signal generator 130 generates first and second drive signals having different frequencies for each vibration mode, and outputs the generated first and second drive signals to the first and second And outputs them to the piezoelectric actuators 120-1 and 120-2, respectively.

According to an embodiment, the vibration mode may include at least two of the first, second or third vibration modes. In the case of including a plurality of vibration modes, even when a speaker of one display panel is used, different vibration modes can be provided according to the use mode.

The first vibration mode is a mode for vibrating only a part of the first and second piezoelectric actuators 120-1 and 120-2. For example, the driving signal generating unit 130 generates a first driving signal having a first frequency belonging to the first frequency band in the first vibration mode, and outputs the generated first driving signal to the first piezoelectric actuator 120- 1). Alternatively, the driving signal generating unit 130 generates a second driving signal having a first frequency belonging to the first frequency band in the first vibration mode, and outputs the generated second driving signal to the second piezoelectric actuator 120-2. . For example, the first frequency band may be 1 kHz to 4 kHz. The first vibration mode is a mode in which the display panel 110 vibrates to perform the first sound providing function. Here, the first sound providing function is a function in which the display panel 110 vibrates to provide a first sound to the user.

The second vibration mode is a mode for simultaneously vibrating the first and second piezoelectric actuators 120-1 and 120-2. The driving signal generating unit 130 generates first and second driving signals in the second vibration mode and outputs the generated first and second driving signals to the first and second piezoelectric actuators 120-1 and 120-2, Can be output simultaneously. Each of the first and second driving signals may have a second frequency belonging to the second frequency band. For example, the second frequency band may be 300 Hz to 15 kHz. The second vibration mode is a mode in which the display panel 110 vibrates to perform the second sound providing function. Here, the second sound providing function is a function in which the display panel 110 vibrates to provide a second sound to the user.

Each of the first and second vibration modes described above is connected to the display panel 110 to perform a role of a receiver, a speaker, or a buzzer for outputting sound in the display device 100, As shown in FIG. For example, the first vibration mode may be a mode for vibrating the display panel 110 to perform a role of a receiver, and the second vibration mode may be a mode for vibrating the display panel 110 to perform a role of a speaker. have.

The third vibration mode is a mode in which the first and second piezoelectric actuators 120-1 and 120-2 are oscillated with a parallax. The driving signal generating unit 130 generates first and second driving signals in the third vibration mode and outputs the generated first and second driving signals to the first and second piezoelectric actuators 120-1 and 120-2, It is possible to output them with a time difference. Each of the first and second driving signals may have a third frequency belonging to the third frequency band. For example, the third frequency band may be 50 Hz to 300 Hz. The third vibration mode is a mode in which the display panel 110 vibrates to perform a haptic function. Here, the haptic function refers to a function of generating various tactile effects to the user on the display panel 110 when the user touches the display panel 110, such as vibration for notification, vibration for touch of the user (for example, Feedback to the touch point).

In the third vibration mode, the piezoelectric actuator located away from the point touched by the user among the first and second piezoelectric actuators 120-1 and 120-2 vibrates first and the piezoelectric actuator located close to the portion touched by the user You can vibrate at a later time.

Further, the second frequency may be smaller than the first frequency, and the third frequency may be smaller than the second frequency, but the embodiments are not limited thereto.

Further, according to the embodiment, the vibration mode may further include a fourth vibration mode described later.

As described above, when a plurality of piezoelectric actuators having different frequency bands or frequency bands not overlapping each other are applied, an optimized output can be provided for each mode.

Hereinafter, embodiments 130A, 130B, and 130C of the drive signal generator 130 shown in FIG. 1A will be described with reference to the accompanying drawings. At this time, it is assumed that N = 2 for convenience of explanation, but even if N is 3 or more, the following description can be applied.

FIG. 3 shows a block diagram of an embodiment 130A of the drive signal generator 130 shown in FIG. 1A.

3, the driving signal generating unit 130A includes a main control unit 131A, a first interface unit 133A, an auxiliary control unit 135, a first and a second D / (DAC) 137A-1 and 137A-2, and first and second amplifying units 139A-1 and 139A-2.

The main control unit 131A determines the vibration mode of the display panel 110 and outputs the determined result as an event signal. That is, the event signal is a signal having information on the determined vibration mode. To this end, the main control unit 131A may include a storage unit M. [ The storage unit M may include a plurality of memories. For example, the storage unit M may include at least two of the first, second, or third memories M1, M2, and M3. In some cases, the third memory M3 may be omitted.

The first memory M1 may store at least one of the first or second audio data. The first audio data may mean data necessary to vibrate the display panel 110 in the first vibration mode. For example, the first audio data may include data relating to at least one of frequency, width, or intensity with which the display panel 110 will vibrate in the first vibration mode. Therefore, the frequency or the like of the drive signal for driving the first or second piezoelectric actuators 120-1 and 120-2 in the first vibration mode can be determined by the first audio data. The second audio data may mean data necessary to vibrate the display panel 110 in the second vibration mode. For example, the second audio data may include data relating to at least one of frequency, width, or intensity with which the display panel 110 will vibrate in the second vibration mode. Therefore, the frequency and the like of the drive signal for simultaneously driving the first and second piezoelectric actuators 120-1 and 120-N in the second vibration mode can be determined by the second audio data.

In addition, the second memory M2 may store haptic data. The haptic data may mean data necessary to vibrate the display panel 110 in the third vibration mode. For example, the haptic data may include data relating to at least one of the frequency, width, or intensity with which the display panel 110 vibrates in the third vibration mode. Therefore, the frequency of the drive signal for driving the first and second piezoelectric actuators 120-1 and 120-2 with a parallax in the third vibration mode, etc. can be determined by the haptic data.

In addition to the first to third vibration modes, the third memory M3 may store data necessary for the display device to perform the fourth vibration mode. Here, the fourth vibration mode may be a mode in which the display device 100 vibrates the display panel 110 to perform various events such as a biometric function or a facial recognition function. In some cases, the third memory M3 may be omitted.

Each of the first to third memories M1 to M3 may be a flash memory type, a hard disk type, a multimedia card micro type, a card type memory A random access memory (SRAM), a random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM) Read-Only Memory), a magnetic memory, a magnetic disk, and an optical disk.

As a result, the main control unit 131A determines the vibration mode of the display panel 110, reads the data stored in the first to third memories M1 to M3 according to the determined result, and outputs the read data as an event signal Can be output.

The first interface unit 133A may be disposed between the main control unit 131A and the auxiliary control unit 135 to interface the first and second interface units 133A and 135 with each other. For example, the first interface unit 133A may serve as a kind of buffer (or latch). That is, when the auxiliary controller 135 performs another function when the event signal is supplied from the main controller 131A, the event signal may not be received. At this time, the first interface unit 133A may temporarily store the event signal until the auxiliary controller 135 can receive the event signal. Alternatively, the first interface unit 133A may be omitted.

The auxiliary control unit 135 determines at least one frequency of the first or second driving data according to the event signal provided from the main control unit 131A and outputs at least one of the first or second driving data having the determined frequency And outputs it.

For example, the auxiliary control unit 135 may include a processing unit 135A and a first data output unit 135B.

The processing unit 135A analyzes the event signal provided from the main control unit 131A, generates basic data for determining at least one frequency of the first or second driving data according to the analyzed result, And outputs it to the first data output unit 135B. The processor 135A may include a signal analyzer 210, first to third basic data generators 212, 214 and 216, and a mixer 218. [

The signal analyzing unit 210 analyzes the event signal provided from the main control unit 131A and outputs the basic data in at least one of the first, second, and third basic data generators 212, 214, and 216, As shown in Fig.

The first basic data generator 212 may generate at least one of the 1-1 or 1-2 basic data in response to the result analyzed by the signal analyzer 210 and output the generated data to the mixer 218. The 1-1 base data has information on the frequency of a driving signal required to vibrate the display panel 110 in the first vibration mode, And has information on the frequency of the drive signal necessary for oscillation.

The second fundamental data generating unit 214 may generate the second fundamental data in response to the result analyzed by the signal analyzing unit 210 and output the second basic data to the mixer 218. The second fundamental data has information on the frequency of the driving signal required to vibrate the display panel 110 in the third vibration mode.

The third basic data generator 216 may generate the third basic data in response to the result analyzed by the signal analyzer 210 and output the third basic data to the mixer 218. The third basic data has information on the frequency of the driving signal required to vibrate the display panel 110 in the fourth vibration mode.

At least two of the first, second, and third vibration modes may be performed in combination, and the fourth vibration mode may be performed. Therefore, the mixer 218 selects at least one of the first, second, third, and second basic data output from the first, second, and third basic data generators 212, 214, And output the mixed result to the first data output unit 135B.

The first data output unit 135B classifies the mixed result output from the mixer 218 into the number N of piezoelectric actuators and outputs the classified result as the first to Nth drive data to the first and second DACs 137A-1 and 137A-2, respectively.

For convenience, the auxiliary control unit 135 is illustrated as including the first data output unit 135B, but the embodiment is not limited to this.

That is, according to another embodiment, the first data output unit 135B may be disposed between the auxiliary control unit 135 and the first and second DACs 137A-1 and 137A-2 instead of being disposed within the auxiliary control unit 135. [ As shown in FIG. In this case, the processing section 135A of the auxiliary control section 135 may be integrated circuit (IC).

The first DAC 137A-1 converts the first drive data in the digital form into an analog form, and outputs the converted result to the first amplifier 139A-1. The second DAC 137A-2 converts the second driving data in a digital form into an analog form, and outputs the converted result to the second amplifier 139A-2.

The first amplifier 139A-1 amplifies the output of the first DAC 137A-1 and outputs the amplified result as the first drive signal to the first piezoelectric actuator 120-1 through the output terminal OUT1 . The second amplifier 139A-2 amplifies the output of the second DAC 137A-2 and outputs the amplified result as the second drive signal to the second piezoelectric actuator 120-2 through the output terminal OUT2 .

Since the intensity of the signal output from the first and second DACs 137A-1 and 137A-2 is small, the first and second amplifying units 139A-1 and 139A-2 amplify the signal.

Accordingly, at least one of the first or second piezoelectric actuators 120-1 and 120-2 vibrates, and the display panel 110 vibrates at least one of the first or second piezoelectric actuators 120-1 and 120-2 It is possible to vibrate in a state required by at least two of the first, second, and third vibration modes.

FIG. 4 is a block diagram of another embodiment 130B of the drive signal generator 130 shown in FIG. 1A.

4, the driving signal generation unit 130B according to another embodiment includes a main control unit 131B, a second interface unit 133B, a second data output unit 135C, a third and a fourth digital / Analog converters 137A-3 and 137A-4, and third and fourth amplifiers 139A-3 and 139A-4.

In the case of the drive signal generator 130B shown in Fig. 4, the processing unit 135A of the sub control unit 135 shown in Fig. 3 is arranged in the main control unit 131B. Unlike the drive signal generator 130A shown in FIG. 3, in the case of the drive signal generator 130B shown in FIG. 4, the mixed result in the mixer 218 is output to the second data output unit 135C And is output to the second interface unit 133B.

Except for this, the driving signal generating unit 130B shown in FIG. 4 is the same as the driving signal generating unit 130A shown in FIG. 3, and a duplicated description will be omitted. That is, the processing section 135A, the storage section M, the second interface section 133B, the second data output section 135C, the third and fourth D / A conversion sections 137A-3, 137A- The storage unit M, the first interface unit 133A, the first data 137A-4, and the third and fourth amplifying units 139A-3 and 139A-4 shown in FIG. Output section 135B, the first and second digital-to-analog converters 137A-1 and 137A-2, and the first and second amplifying sections 139A-1 and 139A-2, respectively.

The main control unit 131B determines a vibration mode and determines at least one frequency of the first or second drive data according to the determined result, and the second interface unit 133B and the second data output unit 135C determine the frequency of at least one of the first drive data and the second drive data, And outputting at least one of the first drive data and the second drive data having the frequency determined by the first drive data generation unit 131B.

The second interface unit 133B may be disposed between the main control unit 131B and the second data output unit 135C and may serve to interface the first and second data output units 135B and 135C with each other. For example, the second interface unit 133B may serve as a kind of buffer (or latch) for storing an event signal output from the main control unit 131B. That is, when the event signal is supplied from the main control unit 131B, the second data output unit 135C may not receive the event signal by performing another function. At this time, the second interface unit 133B can latch the event signal until the second data storage unit 135C can receive the event signal. At this time, the second interface unit 133B may output the latched event signal to the third and fourth DACs 137A-3 and 137A-4 in response to the mixed result in the mixer 218. [ Alternatively, the second interface portion 133B may be omitted in some cases.

The second data output unit 135C classifies the event signal output from the second interface unit 133B so as to correspond to the number of piezoelectric actuators (N = 2), and outputs the classified result as the first and second drive data 3 and the fourth DACs 137A-3 and 137A-4, respectively.

The third DAC 137A-3 converts the first driving data of the digital form into an analog form and outputs it. The fourth DAC 137A-4 converts the second drive data in a digital form into an analog form and outputs it.

The third amplifier 139A-3 amplifies the output of the first DAC 137A-3 and outputs the amplified result as the first drive signal to the first piezoelectric actuator 120-1 through the output terminal OUT3 . The fourth amplifying unit 139A-4 amplifies the output of the second DAC 137A-4 and outputs the amplified result as the second driving signal to the second piezoelectric actuator 120-2 through the output terminal OUT4 .

Since the intensity of the signal output from the third and fourth DACs 137A-3 and 137A-4 is small, the third and fourth amplifying units 139A-3 and 139A-4 amplify the signal.

Accordingly, at least one of the first or second piezoelectric actuators 120-1 and 120-2 vibrates, and the display panel 110 vibrates at least one of the first or second piezoelectric actuators 120-1 and 120-2 It is possible to vibrate in a state required by at least two of the first, second, and third vibration modes.

FIG. 5 is a block diagram of another embodiment 130C of the drive signal generator 130 shown in FIG. 1A.

The driving signal generating unit 130C according to another embodiment includes a main control unit 131C, a fifth digital-analog converting unit (DAC) 137B, and an active amplifying unit 139B as illustrated in FIG. 5 .

The main control unit 131C can determine the vibration mode and output the determined result to the fifth DAC 137B as an event signal. To this end, the main control unit 131C may include the storage unit M shown in FIG.

The fifth DAC 137B converts the digital event signal into an analog form, and outputs the converted result to the active amplifier unit 139B.

The active amplifying unit 139B determines at least one frequency of the first or second driving signal according to the analog type event signal output from the fifth DAC 137B and outputs the first or second driving signal Can be amplified and output. The amplifying unit 139B may include a touch information generating unit 302, a source unit 304, a third data output unit 306, and first and second amplifiers 308 and 309. [

The touch information generating unit 302 adds touch information to an analog event signal when the vibration mode is the third vibration mode and outputs the result to the source unit 304. [ Here, the touch information may include at least one of the coordinates of the touched position or the touch strength. That is, the coordinates of the touched position are displayed as coordinates in the x-axis and the y-axis, and the touch intensity can be displayed as coordinates in the z-axis.

However, when the vibration mode is not the third vibration mode, the touch information generation unit 302 may bypass the analog type event signal to the source unit 304. [

The source unit 304 receives at least one of the first to Nth driving signals having a frequency determined according to the event signal bypassed by the touch information generating unit 302 or the event signal to which the touch information is added, (308, 309) to the corresponding amplifier. To this end, the source unit 304 may incorporate the processing unit 135A shown in FIG.

The corresponding one of the first and second amplifiers 308 and 309 amplifies at least one of the first and second driving signals output from the third data output unit 306 and outputs the amplified result.

The first amplifier 308 amplifies the first driving signal output from the third data output unit 306 and outputs the amplified result to the first piezoelectric actuator 120-1 through the output terminal OUT5. The second amplifier 309 amplifies the second driving signal output from the third data output unit 306 and outputs the amplified result to the second piezoelectric actuator 120-2 through the output terminal OUT6.

Since the intensity of the signal output from the third data output unit 306 is small, the first and second amplifiers 308 and 309 amplify the signal. However, if the intensity of the signal is not small, the first and second amplifiers 308 and 309 may be omitted.

Accordingly, at least one of the first or second piezoelectric actuators 120-1 and 120-2 vibrates, and the display panel 110 vibrates at least one of the first or second piezoelectric actuators 120-1 and 120-2 It is possible to vibrate in a state required by at least two of the first, second, and third vibration modes.

As a result, the display device 100 according to the above-described embodiment can control at least two of the first, second, and third vibration modes, and can also perform the fourth vibration mode.

Meanwhile, the display device 100 according to the above-described embodiment can be applied to various devices. For example, the display device according to an embodiment may be a mobile phone, a multimedia Internet mobile phone, a wireless device, a smart phone, a Bluetooth device, a PDA, a portable computer, a netbook, a display device (including a traveling system and a speedometer), a cockpit control device, a display device, and the like, but the embodiment is not limited thereto.

When the display device according to the above-described embodiment is applied to the electronic device as described above, it is possible to increase the area occupied by the display in the electronic device and simultaneously provide an acoustic / vibration output suitable for the situation.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

100: display device 110: display panel
120-1 to 120-N: First to Nth Piezoelectric Actuators
120A: piezoelectric element 121: internal electrode
122: piezoelectric part 126: external electrode
128:
130, 130A, 130B, and 130C:
131A, 131B, 131C: main control unit 133A: first interface unit
133B: second interface unit 135: auxiliary control unit
135C: second data output section
137A-1, 137A-2, 137A-3, 137A-4, 137B: DAC
139A-1, 139A-2, 139A-3, 139A-4: amplifying unit 139B:
140: frame

Claims (11)

A display panel;
First to Nth piezoelectric actuators disposed on a rear surface of the display panel, the first to Nth piezoelectric actuators vibrating the display panel in response to driving signals of first to Nth (where N is a positive integer of 2 or more) driving signals; And
And a drive signal generator for generating and outputting the first to Nth drive signals having different frequencies for each vibration mode,
The vibration mode
A first vibration mode for vibrating a part of the plurality of piezoelectric actuators;
A second vibration mode for simultaneously vibrating the plurality of piezoelectric actuators; or
And a third vibration mode in which the plurality of piezoelectric actuators are oscillated with a parallax. The display device according to claim 1, wherein each of the first to Nth piezoelectric actuators is smaller in distance from the center of the back surface of the display panel than a first distance is greater than a second distance from an edge of the rear surface. The display device according to claim 1, wherein the first to Nth piezoelectric actuators have a cross section and a planar shape symmetrically arranged with respect to a central axis of the display panel. The apparatus of claim 1, wherein the drive signal generator
A main controller for determining the vibration mode and outputting the determined result as an event signal;
An auxiliary controller for determining at least one frequency among the first through N-th driving data according to the event signal and outputting at least one of first or Nth driving data having a determined frequency;
First to Nth digital-analog converters for respectively converting the first to N-th driving data in digital form into analog form and outputting the analog data; And
And first to Nth amplifying units for amplifying the outputs of the first to Nth digital-analog converting units and outputting the amplified result as the first to Nth driving signals, respectively. The apparatus of claim 1, wherein the drive signal generator
A main controller for determining the vibration mode, determining at least one frequency among the first through N-th drive data according to the determined result, and outputting at least one of first through N-th drive data having a determined frequency;
First to Nth digital-analog converters for respectively converting the first to N-th driving data in digital form into analog form and outputting the analog data; And
And first to Nth amplifying units for amplifying the outputs of the first to Nth digital-analog converting units and outputting the amplified result as the first to Nth driving signals, respectively. The apparatus of claim 1, wherein the drive signal generator
A main controller for determining the vibration mode and outputting the determined result as an event signal;
A digital / analog converter for converting the digital event signal into an analog form; And
And an active amplifier unit for determining at least one of the first to N-th driving signals according to the analog event signal and for amplifying and outputting at least one of the first to N-th driving signals having the determined frequency, Device. 7. The receiver of claim 6, wherein the active amplifier
A touch information generating unit which adds touch information to the analog type event signal when the vibration mode is the third vibration mode and bypasses the analog type event signal when the vibration mode is not the third vibration mode, ;
A source portion for outputting at least one of the first to N-th driving signals having a frequency determined according to the bypassed event signal or the event signal to which the touch information is added; And
And first to Nth amplifiers for amplifying and outputting at least one of the first to Nth driving signals output from the source unit. The method of claim 7,
Coordinates of the touched position; or
And a touch strength. The apparatus of claim 1, wherein the drive signal generator
And generates an n-th (1? N? N) driving signal having a first frequency belonging to the first frequency band in the first vibration mode, and outputs the driving signal to the n-th piezoelectric actuator. 10. The apparatus of claim 9, wherein the drive signal generator
And generates first to Nth driving signals belonging to the second frequency band and having a second frequency smaller than the first frequency in the second vibration mode, and outputs the first to Nth driving signals. The apparatus of claim 1, wherein the drive signal generator
And generates and outputs first to Nth driving signals belonging to the third frequency band and having a third frequency smaller than the second frequency in the third vibration mode.

Images