Touch sensor, touch detection method, and display device

Abstract

The invention relates to a touch sensor, a touch detection method and a display device. The touch sensor includes: a plurality of sensor elements arranged in a matrix shape across a first direction and a second direction crossing the first direction, and capable of transmitting and receiving ultrasonic waves; and a plurality of lines connected to the plurality of sensor elements, where at least one of the plurality of lines is shared by the plurality of sensor elements.

Description

Technical Field

[0001] The present invention relates to a touch sensor, a touch detection method, and a display device. Background Art

[0002] In recent years, display devices that can be operated by touching a display device with a finger, a pen, or the like have become popular. These display devices are equipped with sensors (i.e., touch sensors) that detect contact with the display device. Various configurations are applied to the touch sensors, such as the capacitive method, the conductive film method, the optical method, and the ultrasonic method. Among these methods, the ultrasonic touch sensor has the advantage of being able to detect touch without reducing the transmittance of the panel. Patent Document 1 discloses an ultrasonic touch sensor equipped with a piezoelectric element that generates ultrasonic waves and a sensor element that detects the reflected ultrasonic waves. The touch sensor described in Patent Document 1 detects contact with an object by detecting ultrasonic waves reflected from the object.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-81710.

[0004] The description provided in the background section should not be assumed to be prior art merely because it is mentioned in the background section or is related to the background section. The background section may include information describing one or more aspects of the subject technology. Summary of the Invention

[0005] However, as the number of piezoelectric elements and sensor elements increases, the number of lines also increases, making the circuit configuration complex. In addition, since it is impossible to mount the piezoelectric elements and sensor elements at high density, it may become difficult to improve the resolution of touch detection.

[0006] An advantage of the present invention is to provide a touch sensor and a display device capable of improving the resolution of touch detection.

[0007] The additional features and advantages of the present invention will be described below, and will be partly apparent from the description, or can be learned through the practice of the present invention. These and other advantages of the present invention will be achieved and obtained by the structures specifically pointed out in the written description and claims of the present invention and the drawings.

[0008] To achieve these and other advantages and in accordance with the purpose of the present invention, as specifically implemented and broadly described herein, a touch sensor includes: a plurality of sensor elements arranged in a matrix shape across a first direction and a second direction intersecting the first direction, and capable of transmitting and receiving ultrasonic waves; and a plurality of lines connected to the plurality of sensor elements, wherein at least one of the plurality of lines is shared by the plurality of sensor elements.

[0009] On the other hand, a touch sensor includes: M×N sensor elements, each of the M×N sensor elements including a vibration element that generates ultrasonic waves and a detection element that detects ultrasonic waves; M transmission lines extending in a first direction, and each of the M transmission lines being connected to N vibration elements; and N reception lines extending in a second direction intersecting the first direction, and each of the N reception lines being connected to M detection elements.

[0010] On the other hand, a display device includes: a touch panel including the above touch sensor; and a display panel facing the touch panel.

[0011] On the other hand, a touch detection method includes: generating ultrasonic waves from a plurality of sensor elements arranged in a matrix shape across a first direction and a second direction intersecting the first direction; and receiving the ultrasonic waves among the plurality of sensor elements, wherein the plurality of sensor elements are connected to a plurality of lines, and wherein at least one of the plurality of lines is shared by the plurality of sensor elements.

[0012] It should be understood that the foregoing general description and the following detailed description are both exemplary and explanatory and are intended to provide further explanation of the claimed invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings, which are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. In the drawings:

[0014] Figure 1 is a block diagram of a display device according to a first exemplary embodiment of the present invention;

[0015] Figure 2 is a cross-sectional view of a display panel according to a first exemplary embodiment of the present invention;

[0016] Figure 3 is a cross-sectional view of a touch panel according to a first exemplary embodiment of the present invention.

[0017] Figure 4 is a block diagram of a display device according to a first exemplary embodiment of the present invention;

[0018] Figure 5 is a timing diagram showing the operation of a display device according to a first exemplary embodiment of the present invention;

[0019] Figures 6A to 6D shows a detection method in a display device according to a first exemplary embodiment of the present invention;

[0020] Figure 7 is a block diagram of a display device according to a second exemplary embodiment of the present invention;

[0021] Figure 8 is a timing diagram showing the operation of a display device according to a second exemplary embodiment of the present invention;

[0022] Figure 9A and Figure 9B shows a detection signal in a display device according to a second exemplary embodiment of the present invention;

[0023] Figure 10 is a flowchart of a display device according to a third exemplary embodiment of the present invention.

[0024] Figure 11 is a flowchart of a display device according to a third exemplary embodiment of the present invention.

[0025] Throughout the drawings and the detailed description, unless otherwise specified, the same reference numerals should be understood to represent the same elements, features, and structures. For clarity, illustration, and convenience, the relative dimensions and depictions of these elements may be exaggerated. Detailed Description

[0026] The embodiments of the present invention will be described in detail below with reference to the drawings. Throughout the drawings, elements having common functions are given the same reference numerals, and redundant descriptions are sometimes omitted or simplified. In the following description, when it is determined that a detailed description of a well-known function or configuration related to this document unnecessarily obscures the gist of the inventive concept, its detailed description will be omitted. The progress of the described processing steps and / or operations is an example; however, the order of the steps and / or operations is not limited to the order set forth herein and may be changed as known in the art, except for steps and / or operations that must occur in a specific order. The names of the various elements used in the following description may be selected only for the convenience of writing the specification and may therefore be different from the names used in actual products.

[0027] The advantages and features of the present disclosure and the method of realizing them will be clarified by the following exemplary embodiments described with reference to the drawings. However, the present disclosure may be embodied in different forms and should not be construed as limited to the exemplary embodiments set forth herein. Instead, these exemplary embodiments may be provided so that the present disclosure may be thorough and complete and may help those skilled in the art fully understand the scope of the present disclosure. In addition, the present disclosure is defined only by the scope of the claims.

[0028] The shapes, sizes, dimensions (e.g., length, width, height, thickness, radius, diameter, area, etc.), ratios, angles, number of elements, angles, numerical values, etc. shown in the accompanying drawings for describing various example embodiments of the present disclosure are given only by way of example. Therefore, the present disclosure is not limited to the illustrations in the accompanying drawings. Unless otherwise specified, the same or similar elements are denoted by the same reference numerals throughout the specification. In the following description where a detailed description of a related known function or configuration may unnecessarily obscure the gist of the present disclosure, the detailed description of such known configured functions may be omitted. Any implementation described herein as an "example" is not necessarily to be construed as being preferred or advantageous over other implementations.

[0029] The term "exemplary" is used to indicate being used as an example or illustration. Each aspect is an example aspect. "Embodiment", "example", "aspect", etc. should not be construed as being preferred or advantageous over other implementations. Unless otherwise specified, an embodiment, an example, an example embodiment, an aspect, etc. may refer to one or more embodiments, one or more examples, one or more example embodiments, one or more aspects, etc. In addition, the term "may" encompasses all meanings of the term "can".

[0030] When the terms "comprising", "having", and "including" described in the present disclosure can be used, another part can be added, unless a more restrictive term such as "only" is used. Unless otherwise indicated to the contrary, a term in the singular form can include the plural form.

[0031] When interpreting an element, the element is interpreted as including an error range or tolerance range, even if there is no explicit description of such an error or tolerance range.

[0032] When describing a time relationship, for example, when a time sequence is described as, for example, "after", "subsequent", "next", and "before", discontinuous cases can be included, unless a more restrictive term such as "exactly", "immediately", or "directly" is used.

[0033] In the description of various embodiments of the present disclosure, in the case of describing a positional relationship, for example, when the positional relationship between two parts is described as, for example, "on", "above", "below", and "next to", etc., one or more other parts can be located between the two parts, unless a more restrictive term such as "exactly" or "directly" is used. For example, in the case where an element or layer is disposed "on" another element or layer, a third layer or element can be interposed therebetween.

[0034] In this document, terms such as "below", "lower", "above", "upper", etc. may be used to describe the relationship between components as shown in the figures. It should be understood that these terms are spatially relative and based on the orientation depicted in the drawings.

[0035] Although terms such as "first", "second", A, B, (a), (b), etc. may be used in this document to describe various components, these components should not be construed as being limited by these terms because they are not used to define a specific order or priority. These terms are only used to distinguish one component from another. For example, a first component may be referred to as a second component, and similarly, a second component may be referred to as a first component, without departing from the scope of the present disclosure.

[0036] The term "at least one" should be understood to include any and all combinations of one or more of the associated listed items. For example, the meaning of "at least one of the first element, the second element, and the third element" includes the combination of all three listed elements, the combination of any two of the three elements, and each individual element (the first element, the second element, or the third element).

[0037] As can be fully understood by those skilled in the art, the features of various embodiments of the present disclosure can be partially or wholly coupled or combined with each other, and can operate with each other in various ways and be technically driven. The embodiments of the present disclosure can be executed independently of each other, or can be executed together in a mutually dependent relationship.

[0038] <First Exemplary Embodiment>

[0039] Figure 1 is a block diagram of a display device according to the present invention. The display device according to this exemplary embodiment can be a television display, a computer display, a smartphone, a tablet, a signboard, a flexible display, a household appliance, a vehicle, a wearable device, etc. The display device includes a display controller 1, a display panel 2, and a touch sensor. The touch sensor includes a touch controller 3, a transmission circuit 4, a touch panel 5, and a reception circuit 6. In addition, the touch panel 5 includes a plurality of sensor elements 50, and each sensor element 50 includes a vibration element 51 and a detection element 52, but is not limited thereto.

[0040] The display panel 2 can be a liquid crystal display, an organic EL (electroluminescent) panel, a light-emitting diode (LED) display, a micro LED display, etc. The display panel 2 includes a plurality of pixels arranged in a matrix shape. The display panel 2 displays an image based on an image signal RGB, a main clock signal MCLK, a horizontal synchronization signal Hsync, and a vertical synchronization signal Vsync provided from the display controller 1.

[0041] As an example, the display controller 1 is equipped with a clock circuit, a voltage generation circuit, etc., but is not limited thereto. The display controller 1 outputs an image signal RGB, a main clock signal MCLK, a horizontal synchronization signal Hsync, a vertical synchronization signal Vsync, etc. to the display panel 2.

[0042] The touch panel 5 is formed facing the display panel 2. The touch panel 5 can be formed on the display surface of the display panel 2 or on the back surface of the display panel 2 opposite to the display surface. Here, the horizontal direction of the touch panel 5 is referred to as the X direction (or row direction), the vertical direction of the touch panel 5 is referred to as the Y direction (or column direction), and the vertical direction with respect to the operation surface of the touch panel 5 is referred to as the Z direction.

[0043] Each of the sensor elements 50 includes a vibration element 51 and a detection element 52, and is arranged in a matrix shape of m rows and n columns in the touch panel 5. As an example, Figure 1 Twenty-five sensor elements 50 arranged in a matrix shape of 5 rows and 5 columns are shown. The embodiment is not limited thereto. As an example, m and n can be any natural numbers. As an example, m can be greater than, equal to, or less than n.

[0044] The vibration element 51 vibrates according to the signal applied thereto and generates ultrasonic waves toward the operation surface of the touch panel 5. The frequency of the ultrasonic waves can be changed by changing the frequency of the signal applied to the vibration element 51.

[0045] The detection element 52 is arranged at a position in the sensor element 50 close to the vibration element 51. The ultrasonic waves generated from the vibration element 51 are reflected by the operation surface of the touch panel 5 or an object and detected by the detection element 52. The detection element 52 vibrates by detecting the ultrasonic waves and outputs a signal according to the vibration.

[0046] A plurality of sensor elements 50 share one of the plurality of receiving lines RL1 to RL5. In addition, a plurality of sensor elements 50 share one of the plurality of transmitting lines TL1 to TL5. As a result, compared with the case where lines are formed separately for a plurality of sensor elements 50, the display device of this exemplary embodiment can reduce the number of lines connected to the sensor elements 50.

[0047] The transmission circuit 4 is connected to the plurality of vibration elements 51 of the touch panel 5 through the plurality of transmission lines TL1 to TL5. The transmission circuit 4 transmits drive signals to the plurality of vibration elements 51 of the touch panel 5 through the plurality of transmission lines TL1 to TL5.

[0048] The receiving circuit 6 is connected to the plurality of detection elements 52 of the touch panel 5 through the plurality of receiving lines RL1 to RL5. The receiving circuit 6 outputs the detection signals of the plurality of detection elements 52 received through the plurality of receiving lines RL1 to RL5 to the touch controller 3.

[0049] The touch controller 3 supplies a drive signal for driving the sensor element 50 to the transmission circuit 4. In addition, the touch controller 3 receives a detection signal output from the sensor element 50 through the reception circuit 6. The touch controller 3 detects contact between the object and the touch panel 5 based on the detection signal output from the sensor element 50.

[0050] Figure 2 is a cross-sectional view of a display device according to the present exemplary embodiment, and is a cross-sectional view of Figure 1 A cross-sectional view of the display panel 2 taken along line II'. Figure 2 As shown, as an example, the display device includes a display panel 2 and a touch panel 5 formed on the display panel 2. The display panel 2 includes a substrate 21, a transistor 22, a buffer layer 23, an anode electrode 24, a dam layer 25, an organic light-emitting layer 26, a cathode electrode 27, an insulating layer 28 and an encapsulation layer 29. The embodiment is not limited to this. As an example, one or more of the components mentioned above may be omitted. As an example, one or more additional components may also be included. The substrate 21 is formed of a rigid material such as glass or other organic or inorganic materials. Alternatively, the substrate 21 may be a stretchable flexible substrate. When the substrate 21 is a flexible substrate, the substrate 21 may be formed of a plastic such as polyimide or polyester, but is not limited thereto.

[0051] The buffer layer 23 is formed on the substrate 21. The buffer layer 23 may be formed of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx). The buffer layer 23 has a function of protecting the transistor 22 from impurities such as moisture or oxygen entering from the outside. The buffer layer 23 has a contact hole for connecting the transistor 22 and the anode electrode 24.

[0052] The transistor 22 is embedded in the buffer layer 23. The transistor 22 is formed on the substrate 21. The transistor 22 is a thin film transistor (TFT). The transistor 22 is formed of a material such as polysilicon, amorphous silicon, a compound semiconductor, an oxide semiconductor, an organic semiconductor, etc. The transistor 22 constitutes a circuit of a pixel included in the display panel 2.

[0053] A bank layer 25 is formed on the buffer layer 23. The bank layer 25 may be formed of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), or an organic insulating material, but is not limited thereto. The bank layer 25 has contact holes (or openings) for connecting the anode electrode 24 and the organic light-emitting layer 26. The anode electrode 24 is embedded in the bank layer 25. The anode electrode 24 is formed on the buffer layer 23. In the case where the display device is a top-emission type that emits light upward from the substrate (i.e., in the Z direction), the anode electrode 24 may be formed of an opaque electrode such as silver (Ag), gold (Au), or aluminum (Al), or a transparent electrode, but is not limited thereto. In the case where the display device is a bottom-emission type that emits light toward the substrate (i.e., in the -Z direction), the anode electrode 24 may be formed of a transparent electrode such as indium tin oxide (ITO) or fluorine tin oxide (FTO), but is not limited thereto. The anode electrode 24 is connected to the transistor 22 through the contact hole of the buffer layer 23.

[0054] An organic light-emitting layer 26 or an inorganic light-emitting layer is formed on the bank layer 25. The organic light-emitting layer 26 may be an organic light-emitting diode (OLED), but is not limited thereto. The organic light-emitting layer 26 is connected to the anode electrode 24 through the contact hole of the bank layer 25.

[0055] A cathode electrode 27 is formed on the organic light-emitting layer 26. When the display device is a bottom-emission type that emits light toward the substrate (i.e., in the -Z direction), the cathode electrode 27 may be formed of an opaque electrode such as silver (Ag), gold (Au), or aluminum (Al), or a transparent electrode, but is not limited thereto. When the display device is a top-emission type that emits light upward from the substrate (i.e., in the Z direction), the cathode electrode 27 may be formed of a transparent electrode such as indium tin oxide (ITO) or fluorine tin oxide (FTO).

[0056] An insulating layer 28 is formed on the cathode electrode 27. The insulating layer 28 may be formed of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), or may be formed of an organic insulating material. The insulating layer 28 has a function of insulating the cathode electrode 27 from the outside.

[0057] A encapsulation layer 29 is formed on the insulating layer 28. The encapsulation layer 29 may be formed of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), or may be formed of an organic insulating material. The encapsulation layer 29 has a function of blocking impurities such as moisture or oxygen entering from the outside.

[0058] Figure 3 is a cross-sectional view of a display device according to the present exemplary embodiment and is a cross-sectional view of the touch panel 5 along the Figure 1 line I-I’. As Figure 3As shown, a touch panel 5 is formed on a display panel 2. The touch panel 5 includes a vibration element 51, a detection element 52, an insulating layer 53, an insulating layer 54, and an insulating layer 55. Additionally, the vibration element 51 has an electrode 511, a dielectric 512, and an electrode 513, and the detection element 52 has an electrode 521, a dielectric 522, and an electrode 523.

[0059] The insulating layer 53 is formed on the display panel 2. The insulating layer 53 can be formed of an inorganic insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), or can be formed of an organic insulating material. The insulating layer 53 has a contact hole for connecting the electrode 511 and the dielectric 512. The electrode 511 is embedded in the lower surface of the insulating layer 53. The electrode 511 extends in the X direction and is shared with the electrode 511 of another vibration element 51 in the X direction. The electrode 511 is also formed on the upper surface of the insulating layer 53 through the contact hole of the insulating layer 53. The electrode 511 can be formed of a transparent electrode such as indium tin oxide or fluorine-doped tin oxide, but is not limited thereto. As an example, the electrode 511 can be formed of an opaque electrode such as a metal. The electrode 521 is embedded in the upper surface of the insulating layer 53. The electrode 521 is formed between the portions of the electrode 511 formed on the upper surface of the insulating layer 53. As an example, the electrode 521 can be formed of the same material as the electrode 511, or can be formed of a different material. As an example, the electrode 521 can be formed to have the same thickness at the same height as the portion of the electrode 511 formed on the upper surface of the insulating layer 53, or can have a different thickness at a different height from the portion of the electrode 511 formed on the upper surface of the insulating layer 53.

[0060] The insulating layer 54 is formed on the insulating layer 53. The insulating layer 54 can be formed of the same material or a different material from the insulating layer 53. As an example, the insulating layer 54 can be integrally formed with or separately formed from the insulating layer 53. The insulating layer 54 has a contact hole for connecting the dielectric 522 and the electrode 523.

[0061] The dielectric 512 is embedded in the lower surface of the insulating layer 54. The lower surface of the dielectric 512 is connected to the electrode 511 formed on the upper surface of the insulating layer 53. The dielectric 512 can be formed of materials such as dielectric elastomers, ceramics, barium titanate, lead zirconate titanate, or zinc oxide, but is not limited thereto. The electrode 513 is embedded in the insulating layer 54. The electrode 513 is connected to the upper surface of the dielectric 512. The electrode 513 can be formed of the same material as the electrode 511 or can be formed of a different material from the electrode 511. The dielectric 522 is embedded in the lower surface of the insulating layer 54. The lower surface of the dielectric 522 is connected to the electrode 521 formed on the upper surface of the insulating layer 53. The dielectric 522 can be formed of the same material as the dielectric 512 or can be formed of a different material from the dielectric 512. As an example, the dielectric 522 can be formed to have the same thickness at the same height as the dielectric 512 or can have a different thickness at a different height from the dielectric 512.

[0062] The insulating layer 55 is formed on the insulating layer 54. The insulating layer 55 can be formed of the same material or a different material from the insulating layer 53. The electrode 523 is embedded in the lower surface of the insulating layer 55. The electrode 523 extends in the X direction and is shared with the electrode 523 of another detection element 52 in the X direction. The electrode 523 is connected to the upper surface of the dielectric 522 through a contact hole in the insulating layer 54. The electrode 523 can be formed of the same material or a different material from the electrode 511.

[0063] The electrode 513, together with the electrodes 513 of other vibration elements 51 arranged in the Y direction, is connected to the transmission circuit 4 through one of the transmission lines TL1 to TL5. The electrode 511 is connected to the transmission circuit 4 through a line. The electrodes 511 and 513 receive drive signals from the transmission circuit 4.

[0064] When drive signals are sent to the electrodes 511 and 513, an electrostatic force is generated between the electrodes 511 and 513. The electrodes 511 and 513 are attracted to each other due to the electrostatic force, causing the dielectric 512 to contract in the Z direction. In this way, the vibration element 51 contracts in the Z direction. When drive signals are not applied to the electrodes 511 and 513, the electrostatic force generated between the electrodes 511 and 513 disappears. The electrodes 511 and 513 attracted to each other due to the electrostatic force move away from each other, causing the dielectric 512 to extend in the Z direction. As a result, the vibration element 51 extends in the Z direction. That is, the vibration element 51 contracts and extends according to the drive signals sent to the electrodes 511 and 513, and the vibration element 51 can emit ultrasonic waves to the touch panel 5.

[0065] When ultrasonic waves are applied to the dielectric 522, a detection signal can be generated between the electrodes 521 and 523 due to the vibration of the dielectric 522. Therefore, the ultrasonic waves generated by the vibration element 51 can be detected based on the detection signal output from the detection element 52.

[0066] The electrode 523 of the other detection element 52 arranged in the X direction is connected to the receiving circuit 6 through one of the plurality of receiving lines RL1 to RL5 together with the electrode 523. The electrode 521 is connected to the receiving circuit 6 through a line.

[0067] Figure 4 is a block diagram of a display device according to the present exemplary embodiment, which shows a touch controller 3, a transmission circuit 4, a touch panel 5, and a receiving circuit 6. The touch controller 3 is equipped with a CPU (Central Processing Unit) 301, a ROM (Read Only Memory) 302, a RAM (Random Access Memory) 303, a memory device 304, a communication I / F 305, and a bus 306. The components of the touch controller 3 are connected to each other through the bus 306. The embodiment is not limited thereto. As an example, one or more of the above-mentioned components may be omitted. As an example, one or more additional components may also be included.

[0068] The CPU 301 is a processor that performs predetermined operations according to programs stored in the ROM 302, the memory device (304), etc., and also has a function of controlling each part of the touch controller 3. The CPU 301 loads the programs stored in the ROM 302, the memory device (304), etc. into the RAM 302 and runs it. The RAM 302 is configured as a volatile memory medium and provides a temporary memory area necessary for the operation of the CPU 301. The ROM 302 is configured as a non-volatile memory medium and stores necessary information such as operation programs of the CPU 301. The memory device 304 is configured as a non-volatile memory medium, such as a flash memory, a hard disk, etc. The communication I / F 305 is a communication interface for wireless communication or wired communication and is a module for performing communication with other devices.

[0069] As an example, the transmission circuit 4 is provided with a DA converter 401 and a multiplexer 402, but is not limited thereto. The DA converter 401 converts the digital signal output from the CPU 301 into a drive signal of a predetermined frequency. The drive signal is output to the multiplexer 402. The multiplexer 402 is provided with an input node and a plurality of output nodes. In addition, the multiplexer 402 is provided with a control node. The drive signal is input from the DA converter 401 to the input node. The control signal from the CPU 301 is input to the control node. The multiplexer 402 can select an output node based on the control signal of the CPU 301. The transmission lines TL1 to TL5 are connected to the output nodes. The drive signal of a predetermined frequency is sequentially output to the vibration elements 51 through the transmission lines TL1 to TL5.

[0070] As an example, the reception circuit 6 is provided with a multiplexer 601, an amplifier circuit 602, and an AD converter 603, but is not limited thereto. The multiplexer 601 is provided with a plurality of input nodes and an output node. In addition, the multiplexer 601 is provided with a control node. The reception lines RL1 to RL5 are connected to the input nodes. The detection signals are input from the detection elements 52 to the input nodes through the reception lines RL1 to RL5. The control signal from the CPU 301 is input to the control node, and the detection signals of the reception lines RL1 to RL5 are sequentially output to the output node according to the control signal. The amplifier circuit 602 includes a differential amplifier circuit and amplifies the voltage of the weak detection signal output from the detection element 52. The AD converter 603 includes a comparison circuit and a reference voltage generation circuit, and converts the detection signal into a digital signal. The AD converter 603 outputs the digital signal to the CPU 301 through the bus 306.

[0071] Figure 5 is a timing chart showing the operation of the display device according to the present exemplary embodiment. For simplicity, it is assumed that the touch panel 5 has three transmission lines TL1 to TL3, three reception lines RL1 to RL3, and nine (i.e., 3 * 3) sensor elements 50. At time t1, the transmission circuit 4 switches the multiplexer 402 and selects the transmission line TL1 as the output node. At times t1 to t2, the transmission circuit 4 outputs a drive signal to the three vibration elements 51 through the transmission line TL1. The three vibration elements 51 vibrate according to the drive signal and generate ultrasonic waves toward the operation surface of the touch panel 5. Each ultrasonic wave generated by the three vibration elements 51 is reflected by the operation surface or an object of the touch panel 5 and reaches each of the nine detection elements 52. The ultrasonic wave paths from the vibration elements 51 to the detection elements 52 are different for each of the nine detection elements 52. Therefore, the detection signals output from the nine detection elements 52 can also be different.

[0072] At time t2 to t3, the receiving circuit 6 switches the multiplexer 601 and selects the receiving line RL1 as the input node. Here, since the three detection elements 52 are connected to the receiving line RL1, the three detection signals are superimposed and output to the receiving line RL1. The receiving circuit 6 receives the detection signal in the receiving line RL1, and the touch controller 3 stores the AD-converted detection signal in the memory device 304.

[0073] At time t3 to t4, the transmitting circuit 4 outputs a driving signal to the three vibrating elements 51 through the transmitting line TL1. At time t4 to t5, the receiving circuit 6 selects the receiving line RL2 and receives the detection signal in the receiving line RL2. The touch controller 3 stores the AD-converted detection signal in the memory device 304.

[0074] At time t5 to t6, the transmitting circuit 4 also outputs a driving signal to the three vibrating elements 51 through the transmitting line TL1. At time t6 to t7, the receiving circuit 6 selects the receiving line RL3 and receives the detection signal in the receiving line RL3. After AD conversion, the detection signal is stored in the memory device 304.

[0075] At time t7, the transmitting circuit 4 switches the output node of the multiplexer 402 from the transmitting line TL1 to the transmitting line TL2. The transmitting circuit 4 outputs a driving signal to the vibrating element 51 three times through the transmitting line TL2 (i.e., at time t7 to t8, t9 to t10, and t11 to t12). The receiving circuit 6 sequentially selects the receiving lines RL1 to RL3 through the multiplexer 601, and receives the detection signal in each of the receiving lines RL1 to RL3 (i.e., in each of time t8 to t9, t10 to t11, and t12 to t13). The touch controller 3 AD-converts the received detection signal and stores it in the memory device 304.

[0076] Similarly, at time t13, the transmitting circuit 4 switches the output node of the multiplexer 402 from the transmitting line TL2 to the transmitting line TL3. The transmitting circuit 4 outputs a driving signal to the vibrating element 51 three times through the transmitting line TL3 (i.e., at time t13 to t14, t15 to t16, and t17 to t18). The receiving circuit 6 sequentially selects the receiving lines RL1 to RL3 through the multiplexer 601, and receives the detection signal in each of the receiving lines RL1 to RL3 (i.e., in each of time t14 to t15, t16 to t17, and t18 to t19). The received detection signal is AD-converted and then stored in the memory device 304.

[0077] As described above, the touch controller 3 can obtain 3 * 3 = 9 detection signals corresponding to the combinations of the transmitting lines TL1 to TL3 and the receiving lines RL1 to RL3.

[0078] In the following, reference is made to Figure 5 a method for specifying a contact position between an object and a touch panel 5. The waveform change of a detection signal increases as the ultrasonic transmission distance from a vibration element 51 that generates ultrasonic waves to a detection element 52 that detects the ultrasonic waves becomes shorter. For example, it is assumed that an object has come into contact at a position corresponding to a sensor element 50 connected to a receiving line RL1 and a transmitting line TL2. In a case where an ultrasonic wave is generated by a vibration element 51 in the sensor element 50 connected to the transmitting line TL2 and the ultrasonic wave is detected by a detection element 52 connected to the receiving line RL1, the ultrasonic transmission distance becomes the shortest. Therefore, among nine detection signals corresponding to combinations of transmitting lines TL1 to TL3 and receiving lines RL1 to RL3, the detection signal corresponding to the receiving line RL1 and the transmitting line TL2 has the largest waveform change of the detection signal. The touch controller 3 can specify the contact position of the object by determining the detection signal having the largest waveform change.

[0079] In addition, the method for determining the contact position of the object is not limited to the method for determining the detection signal having the largest waveform change. For example, the touch controller 3 can specify the contact position of the object by determining a detection signal having a waveform change greater than a predetermined threshold value. As a result, even when the object comes into contact with the touch panel 5 at a plurality of positions, the touch controller 3 can specify the contact positions.

[0080] The waveform change of the above-described detection signal can be determined by various methods. In the following, reference is made to Figures 6A to 6D a method for determining the waveform change of the detection signal.

[0081] Figures 6A to 6D FIG. shows detection signals in a display device according to the present exemplary embodiment. In Figures 6A to 6D FIG., a signal component A represents a reflected wave from the touch panel 5, and a signal component B represents a reflected wave from the object. Further, in Figure 6A FIG., the waveform of the ultrasonic frequency and the waveform of the envelope are shown together, but in Figures 6B to 6D FIG., the waveform of the ultrasonic frequency is omitted, and the waveform of the envelope is shown as the detection signal.

[0082] Figure 6AA determination method based on the time difference of detection signals is shown. The ultrasonic waves generated from the vibration element 51 are emitted in all directions and repeatedly reflected within the touch panel 5. Therefore, the detection signals can include multiple signal components based on the first-order reflected waves and the higher-order reflected waves. Here, when an object comes into contact with the touch panel 5, the ultrasonic waves from the vibration element 51 are not only reflected by the touch panel 5 but also reflected by the object. Therefore, the detection signals include the signal component B of the reflected waves from the object. Here, the change in the detection signals can be detected by determining whether the time difference Δt between the signal component A and the signal component B is within a known range. That is to say, if the time difference Δt is within the known range, the touch controller 3 can determine the contact with the object.

[0083] Figure 6B A determination method based on the voltage difference of detection signals is shown. When the touch panel 5 is touched, the detection signals can include the signal component A, and can also include the signal component B based on the reflected waves from the object. The touch controller 3 can determine the contact of the object by determining whether the voltage difference ΔV between the peak voltage Va of the signal component A and the peak voltage Vb of the signal component B is within a known range.

[0084] Figure 6C A determination method based on the time span of detection signals is shown. The time span of the detection signals can be detected as, for example, the time when the detection signals exceed a predetermined threshold voltage Vth. The change in the detection signals can be detected by determining whether the difference between the time span ta of the signal component A and the time span tb of the signal component B is within a known range.

[0085] Figure 6D A determination method based on the spectrum of detection signals is shown. In Figure 6D the horizontal axis represents the frequency, and the vertical axis represents the sound pressure. The spectrum can be calculated by, for example, performing a Fourier transform on the detection signals. The frequency of the ultrasonic waves generated from the vibration element 51 changes by passing through the dielectric in the touch panel 5, etc. Therefore, the frequency of the detection signals changes based on the transmission distance, transmission medium, etc. As Figure 6D shown, the spectrum A shows the reflected waves from the touch panel 5, and the spectrum B shows the reflected waves from the object. The touch controller 3 can detect the contact between the object and the touch panel 5 based on the peak frequencies fa and fb of the spectrum of the detection signals.

[0086] The touch controller 3 can use the above determination method to detect the contact between the object and the touch panel 5 based on the waveform change of the detection signals after AD conversion.

[0087] According to this exemplary embodiment, a plurality of sensor elements 50 share one receiving line among a plurality of receiving lines. In addition, a plurality of sensor elements 50 share one transmitting line among a plurality of transmitting lines. This makes it possible to reduce the number of lines connected to the sensor elements 50 and simplify the circuit configuration as compared with the case where lines are separately formed for the plurality of sensor elements 50. In addition, since the sensor elements 50 can be mounted at high density, the resolution of touch detection can be improved.

[0088] <Second Exemplary Embodiment>

[0089] A display device according to the second exemplary embodiment is described. The display device according to this embodiment is different from the first exemplary embodiment in that it uses ultrasonic waves of different frequencies. In the following, the description focuses on the configuration different from the first exemplary embodiment.

[0090] Figure 7 is a block diagram of a display device according to the present exemplary embodiment, which shows a touch controller 3, a transmission circuit 4, a touch panel 5, and a reception circuit 6. The transmission circuit 4 is equipped with a plurality of DA converters 401. Each of the plurality of DA converters 401 is formed for each vibration element 51. As an example, each of the plurality of DA converters 401 is formed for a corresponding row of vibration elements in the vibration elements 51. As an example, each of the plurality of DA converters 401 is formed for a corresponding one of the transmission lines TL1 to TL5. The CPU 301 outputs different digital signals to the plurality of DA converters 401 respectively, and the plurality of DA converters 401 can generate drive signals of different frequencies respectively. With this configuration, a plurality of drive signals having different frequencies can be output to the transmission lines TL1 to TL5 simultaneously. Similar to the first exemplary embodiment, the reception circuit 6 sequentially selects the reception lines RL1 to RL5 through the multiplexer 601 and receives the detection signals.

[0091] Figure 8 is a timing chart showing the operation of the display device according to the present exemplary embodiment. As Figure 5 shown, it is assumed that the touch panel 5 has three transmission lines TL1 to TL3, three reception lines RL1 to RL3, and nine (3 * 3) sensor elements 50.

[0092] At times t1 to t2, the reception circuit 6 switches the multiplexer 601 and selects the reception line RL1 as the input node. The transmission circuit 4 outputs drive signals to the plurality of transmission lines TL1 to TL3 simultaneously. As an example, the transmission circuit 4 outputs a drive signal with a frequency of f1 to the transmission line TL1, a drive signal with a frequency of f2 to the transmission line TL2, and a drive signal with a frequency of f3 to the transmission line TL3. As a result, ultrasonic waves of different frequencies f1, f2, and f3 are generated simultaneously.

[0093] At times t2 to t3, the receiving circuit 6 selects the receiving line RL1 and receives the detection signals of the three detection elements 52 through the receiving line RL1. The detection signals of the receiving line RL1 include signal components having frequencies f1, f2, and f3. In this way, the receiving circuit 6 can receive the detection signals including the signal components of the three frequencies f1, f2, and f3.

[0094] At times t3 to t5, the transmitting circuit 4 simultaneously outputs drive signals to a plurality of transmitting lines TL1 to TL3. The receiving circuit 6 selects the receiving line RL2 and receives the detection signals in the receiving line RL2.

[0095] At times t5 to t7, the transmitting circuit 4 simultaneously outputs drive signals to a plurality of transmitting lines TL1 to TL3. The receiving circuit 6 selects the receiving line RL3 and receives the detection signals in the receiving line RL3.

[0096] Also in this exemplary embodiment, the contact position between the object and the touch panel 5 can be specified based on the temporal change of each of the plurality of detection signals. That is, as the transmission distance of the ultrasonic wave from the vibration element 51 that generates the ultrasonic wave to the detection element 52 that detects the ultrasonic wave becomes shorter, the waveform change of the detection signal becomes larger. The touch controller 3 can specify the contact position of the object by determining the detection signal having the largest waveform change. In particular, in this exemplary embodiment, since the detection signal includes a plurality of frequency components corresponding to a plurality of transmitting lines (or a plurality of drive signals), it is easy to determine which transmitting line the changed frequency component in the detection signal corresponds to. Therefore, the contact position can be specified in a short time.

[0097] In this exemplary embodiment, the method for determining the contact position of the object is not limited to the method for determining the detection signal having the largest change in the detection signal. For example, the contact position of the object can be specified based on the frequency change of the signal components included in the detection signal. Hereinafter, with reference to Figure 9A and Figure 9B the method for specifying the contact position will be described.

[0098] Figure 9A and Figure 9B show the detection signals in the display device according to this exemplary embodiment, and show the spectrum obtained by the Fourier transform of the detection signals. In Figure 9A and Figure 9B the horizontal axis represents the frequency, and the vertical axis represents the sound pressure.

[0099] Figure 9AShows the spectrum when there is no contact between the object and the touch panel 5. As described above, the detection signal includes signal components of the driving signal having frequencies f1, f2, and f3. Therefore, the peak frequencies of the spectrum have frequencies f1, f2, and f3. In addition, as an example, when the ultrasonic wave generated from the vibration element 51 is transmitted and reflected from the touch panel 5, the frequency of the ultrasonic wave may shift. Therefore, the peak frequencies of the spectrum may include a predetermined error with respect to the frequencies f1, f2, and f3 of the driving signal.

[0100] Figure 9B Shows the spectrum when there is contact between the object and the touch panel 5. When the object contacts the touch panel 5, the ultrasonic wave is reflected from the touch panel 5 and also from the object. Due to the change in the transmission distance of the ultrasonic wave, the ultrasonic wave reflected from the object has a different frequency from the ultrasonic wave reflected from the touch panel 5. The sound pressure at frequency f2 decreases, and a peak appears at frequency f2a near frequency f2. The touch controller 3 can detect the contact between the object and the touch panel 5 from the peak frequency of the spectrum of the detection signal.

[0101] The change in the peak frequency of the spectrum of the detection signal occurs not only at frequency f2 but also at frequencies f1 and f3. In Figure 9B Among them, the spectrum change at frequency f2 is greater than the spectrum changes at frequencies f1 and f3. Therefore, among the signal components of the detection signal, the signal component based on the ultrasonic wave generated from the vibration element 51 in the sensor element 50 connected to the transmission line TL2 changes the most. The touch controller 3 determines that the object contacts at the position corresponding to the transmission line TL2 by determining the signal component with the largest waveform change of the detection signal. The touch controller 3 determines the detection signal with the largest spectral change at frequency f2 in the detection signals corresponding to the receiving lines RL1 to RL3 to indicate the contact position of the object.

[0102] Also in this exemplary embodiment, the touch controller 3 can indicate the contact position of the object by comparing the detection signals corresponding to the receiving lines RL1 to RL3.

[0103] Also in this exemplary embodiment, a plurality of sensor elements 50 share one receiving line among a plurality of receiving lines. In addition, a plurality of sensor elements 50 share one transmission line among a plurality of transmission lines. This makes it possible to simplify the circuit configuration while also densely mounting the sensor elements 50 to improve the resolution of touch detection. In addition, in this exemplary embodiment, the transmission circuit 4 simultaneously transmits a plurality of driving signals having different frequencies to a plurality of transmission lines. This makes it possible to shorten the time required to indicate the contact position compared to the first exemplary embodiment in which the driving signal is sequentially transmitted to a plurality of transmission lines.

[0104] <Third Exemplary Embodiment>

[0105] Describe the display device in this exemplary embodiment. The display device in this exemplary embodiment is different from that in the first exemplary embodiment in that it detects touches and indicates the contact positions by pre-creating a learning model generated by machine learning. In the following, the description focuses on the configurations different from those in the first exemplary embodiment.

[0106] Figure 10 It is a flowchart of the display device according to this exemplary embodiment, which shows the generation process of the learning model. The machine learning in this exemplary embodiment is supervised learning using teaching data, and the detection signals obtained from the plurality of sensor elements 50 are used as the teaching data. The touch controller 3 acquires the teaching data (step S101). The touch controller 3 performs machine learning based on the teaching data (step S102). The touch controller 3 generates a learning-completed model by repeatedly performing machine learning. The generated learning model is stored in the database of the display device (step S103). The embodiment is not limited thereto. As an example, the machine learning in this exemplary embodiment and its learning can also be unsupervised learning without using teaching data.

[0107] Figure 11 It is a flowchart of the display device according to this exemplary embodiment, which shows the calculation process of generating the learning model.

[0108] First, the touch controller 3 receives detection signals from the plurality of sensor elements 50 (step S201). The touch controller 3 calculates the feature amounts of the detection signals for each of the plurality of detection signals (step S202). The feature amounts of the detection signals can be the time difference, voltage difference, time span, and / or peak frequency of the spectrum of the detection signals. Subsequently, the touch controller 3 detects the contact between the object and the touch panel 5 from the feature amounts of the detection signals based on the learning-completed model, and indicates the contact position between the object and the touch panel 5 (step S203).

[0109] As described above, according to this exemplary embodiment, by using the learning model that associates the feature amounts of the detection signals and the contact of the object, the contact between the object and the touch panel 5 can be detected and the contact position can be indicated. The feature amounts of the detection signals vary according to the ultrasonic transmission path from the vibration element 51 that generates ultrasonic waves to the detection element 52 that detects the ultrasonic waves. Therefore, depending on the ultrasonic transmission path, it may be difficult to distinguish the change in the feature amounts of the detection signals caused by the contact of the object from the change in the detection signals caused by the transmission of the ultrasonic waves. In this exemplary embodiment, by using the learning model that associates the feature amounts of the detection signals and the contact of the object, the touch detection accuracy of the display device can be improved.

[0110] According to the above-mentioned present invention, a touch sensor and a display device capable of improving the resolution of touch detection can be provided.

[0111] It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the present invention. Accordingly, the present invention is intended to cover modifications and variations of the present invention as long as they fall within the scope of the appended claims and their equivalents.

[0112] Cross - reference to related applications

[0113] This application claims the priority and benefit of Japanese Patent Application No. 2023 - 200835, filed in Japan on November 28, 2023, which is hereby incorporated by reference in its entirety for all purposes as if fully set forth herein.

Claims

1. A touch sensor, comprising: a plurality of sensor elements arranged in a matrix shape along a first direction and a second direction intersecting the first direction and capable of transmitting and receiving ultrasonic waves; as well as a plurality of wires connected to the plurality of sensor elements, At least one of the plurality of lines is shared by at least a portion of the plurality of sensor elements.

2. The touch sensor according to claim 1, wherein: Each of the plurality of sensor elements includes a vibration element that generates the ultrasonic wave according to a driving signal. wherein the plurality of lines include a plurality of transmission lines extending in the first direction and connected to a plurality of vibration elements, and Each of the plurality of transmission lines is shared by sensor elements arranged in a row in the first direction.

3. The touch sensor according to claim 2, wherein: Each of the plurality of sensor elements includes a detection element that detects the ultrasonic wave and outputs a detection signal. wherein the plurality of lines include a plurality of receiving lines extending in the second direction and connected to a plurality of detection elements, and Each of the receiving lines is shared by sensor elements arranged in a row in the second direction.

4. The touch sensor according to claim 3, further comprising a control unit, which transmits the driving signals to the plurality of vibration elements through the plurality of transmitting lines, and receives the detection signals from the plurality of detection elements through the plurality of receiving lines.

5. The touch sensor according to claim 4, wherein: The control unit sequentially transmits the driving signal having the same frequency to each of the plurality of transmission lines, and detects a touch based on the detection signal in each of the plurality of reception lines.

6. The touch sensor according to claim 5, wherein: The control unit detects the touch based on a change in the detection signal.

7. The touch sensor according to claim 5, wherein: The control unit detects the touch based on a time difference between a plurality of signal components included in the detection signal.

8. The touch sensor according to claim 5, wherein: The control unit detects the touch based on a voltage difference between peaks of a plurality of signal components included in the detection signal.

9. The touch sensor according to claim 5, wherein: The control unit detects the touch based on a time span of a plurality of signal components included in the detection signal.

10. The touch sensor according to claim 5, wherein: The control unit detects the touch based on a frequency change of a plurality of signal components included in the detection signal.

11. The touch sensor according to claim 4, wherein: The control unit simultaneously transmits a plurality of driving signals having different frequencies to the plurality of transmission lines, and detects a touch based on the detection signal in each of the plurality of reception lines.

12. The touch sensor according to claim 11, wherein: The control unit detects the touch based on changes in a plurality of frequency components included in the detection signal.

13. The touch sensor according to claim 10, wherein: The control unit detects the touch based on a peak of a frequency spectrum of the detection signal.

14. The touch sensor according to claim 12, wherein: The control unit specifies the touch position based on a value of a detection signal having a largest change among the plurality of detection signals.

15. The touch sensor according to claim 12, wherein: The control unit specifies a plurality of touch positions based on a change in each of the plurality of detection signals.

16. The touch sensor according to claim 4, wherein: The control unit includes a learning model that receives data representing a feature amount of the detection signal as input and outputs data representing a touch position.

17. The touch sensor according to claim 16, wherein: The feature amount includes at least one of a time difference between a plurality of signal components included in the detection signal, a voltage difference between peaks of the plurality of signal components, a time span of the plurality of signal components, and a frequency change of the plurality of signal components.

18. The touch sensor according to claim 4, wherein: The control unit further includes a selection unit for selecting a reception line connected to the control unit from among the plurality of reception lines, and The selection unit sequentially selects the receiving lines connected to the control unit.

19. The touch sensor according to claim 1, wherein: Each of the plurality of sensor elements includes a vibration element that generates the ultrasonic wave according to a driving signal and a detection element that detects the ultrasonic wave and outputs a detection signal, and The vibration element and the detection element are arranged to overlap each other in the first direction and the second direction.

20. The touch sensor according to claim 1, wherein: Each of the plurality of sensor elements includes a vibration element and a detection element, wherein each of the vibration element and the detection element comprises a first electrode, a dielectric and a second electrode, wherein the dielectric of the vibration element is configured to contract or extend according to a driving signal sent to the first electrode and the second electrode of the vibration element, thereby emitting the ultrasonic wave, and When the ultrasonic wave is applied to the dielectric of the detection element, a detection signal is generated between the first electrode and the second electrode of the detection element due to vibration of the dielectric of the detection element.

21. The touch sensor according to claim 20, wherein: The first electrode and the second electrode of the vibration element and the first electrode and the second electrode of the detection element are formed of transparent electrodes.

22. A touch sensor, comprising: M×N sensor elements, each of the M×N sensor elements includes a vibration element that generates ultrasonic waves and a detection element that detects the ultrasonic waves, and the M×N sensor elements are arranged in a matrix shape having M columns and N rows along a first direction and a second direction intersecting the first direction, where M and N are natural numbers; M transmission lines, the M transmission lines extending along the first direction, and each of the M transmission lines connected to N vibration elements; as well as N receiving lines extend in the second direction, and each of the N receiving lines is connected to M detection elements. 23 . The touch sensor according to claim 22 , further comprising a control unit, wherein the control unit transmits a driving signal to the vibration element through the transmission line and receives a detection signal from the detection element through the reception line.

24. The touch sensor according to claim 23, wherein: The control unit selects the M transmission lines in sequence and sends the driving signals of the same frequency to the selected transmission lines, and The control unit selects the N receiving lines in sequence and receives the detection signal through the selected receiving lines.

25. The touch sensor according to claim 23, wherein: The control unit simultaneously sends M driving signals of different frequencies to the M transmission lines, and The control unit selects the N receiving lines in sequence and receives the detection signal through the selected receiving lines.

26. A display device, comprising: A touch panel comprising the touch sensor according to any one of claims 1 to 21; as well as A display panel faces the touch panel.

27. A display device, comprising: A touch panel comprising the touch sensor according to any one of claims 22 to 25; as well as A display panel faces the touch panel.

28. A touch detection method, the touch detection method comprising the following steps: generating ultrasonic waves from a plurality of sensor elements arranged in a matrix shape along a first direction and a second direction intersecting the first direction; as well as receiving the ultrasonic wave in the plurality of sensor elements, wherein the plurality of sensor elements are connected to a plurality of lines, and At least one of the plurality of lines is shared by at least a portion of the plurality of sensor elements.

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