Interactive display device and method of driving the same

Abstract

An interactive display apparatus and a driving method thereof are provided, which can reduce the size of a frame area around a display area while improving sensitivity in a touch panel. The display apparatus includes driving electrodes in a display area on a substrate; detection electrodes for forming a sensor; a driving unit for selecting and driving the driving electrodes. The driving unit includes a random number generator for generating pseudo random numbers; a shift register for shifting values of the pseudo random numbers, the shift register including registers corresponding to the driving electrodes; a controller for driving the corresponding driving electrodes according to the values of the pseudo random numbers stored in the registers.

Description

TECHNICAL FIELD

[0001] The present application relates to an interactive display device and a driving method thereof, and more particularly, to a display device in which a capacitive touch panel function and a display panel such as an OLED display panel are integrated, and a driving method thereof. BACKGROUND

[0002] A screen of an interactive electronic device such as a smart phone has a touch detection function of being operated by a finger, a palm, or a stylus pen. Conventionally, a touch panel is known to be integrated with a display. In this type of touch panel, a touch panel having a touch panel function mounted on a substrate of a liquid crystal display is called an on-cell type touch panel. The on-cell type touch panel does not require an additional process compared to an external type touch panel in which a touch panel device is connected to a liquid crystal panel, and thus can reduce costs. In addition, the on-cell type touch screen has the following advantages: it can improve light transmittance, reduce the overall thickness. In addition, it can make the manufactured on-cell type touch screen lighter in weight, and can reduce the width of a frame area around a display area.

[0003] Although there are various touch detection methods for touch detection at present, a capacitive touch panel in which electrodes extending in one direction are disposed to intersect each other is known as a touch detection method of a smart phone and a mobile phone. In a capacitive touch panel sensor, a display area on a glass substrate is provided with driving electrodes and detection electrodes facing the driving electrodes and forming a capacitance between the driving electrodes. The sensor detects the position of an adjacent target object according to a detection signal output from the detection electrodes according to a slight change in the capacitance.

[0004] In the current on-cell type capacitive touch panel, the sensor part has a large capacitance. Since it is difficult to detect a slight change in the capacitance, the sensitivity of the sensor of the touch panel is low.

[0005] For example, when performing fingerprint authentication, for each frame, it is necessary to detect the subtle difference in light reflected by the object, and a high SN ratio is required. If the SN ratio is low, the acquired fingerprint image will have a lot of noise, which will adversely affect the authentication of the fingerprint.

[0006] A code division multiplexing (CDM) driving method of an image sensor is known as a method of improving the SN ratio and improving the detection accuracy of the touch panel. In the CDM driving method, a touch driving signal having a phase determined according to a spread code is supplied to a selected driving electrode.

[0007] In the case of the CDM driving method, since the gate lines are simultaneously turned on, many data (detection signals) must be simultaneously collected. However, when a high-order spread code is generated, the circuit configuration becomes very complicated. In this case, the size of the spread code generation circuit becomes large. Therefore, when this circuit is mounted in the frame area of the display area, the width of the frame area and the display substrate become larger. Further, when this circuit is provided outside the display substrate, the touch panel electrode becomes longer, which increases the resistance of the touch line. SUMMARY

[0008] The present application provides an interactive display device which can reduce the size of the frame area around the display area while improving the sensitivity in the touch panel.

[0009] According to a first aspect, there is provided an interactive display device, comprising:

[0010] a plurality of drive electrodes provided in a display area on a substrate;

[0011] a plurality of detection electrodes facing the drive electrodes for forming a sensor;

[0012] a detection unit for detecting the position of an adjacent target object from detection signals output from the plurality of detection electrodes;

[0013] a drive unit for selecting and driving the plurality of drive electrodes;

[0014] wherein the drive unit comprises:

[0015] a random number generator for generating pseudo random numbers;

[0016] a shift register having a plurality of registers for shifting the values of the pseudo random numbers generated by the random number generator, the plurality of registers corresponding to the plurality of drive electrodes;

[0017] a controller for driving the corresponding drive electrodes according to the values of the pseudo random numbers stored in the plurality of registers.

[0018] According to this implementation, the drive unit comprises: a random number generator for generating pseudo random numbers; a shift register for shifting the values of the pseudo random numbers, the shift register comprising registers corresponding to the drive electrodes; and a controller for driving the corresponding drive electrodes according to the values of the pseudo random numbers stored in the registers. Therefore, the size of the touch driver for driving the touch sensor can be reduced.

[0019] According to a possible implementation of the first aspect, the sensor is formed on a different plane from a substrate of the display device and is directly connected to a circuit of the display device.

[0020] According to the implementation, the CDM driving method based on the pseudo-random number can be applied to the capacitive sensor.

[0021] According to a possible implementation of the first aspect, the display device further includes:

[0022] a plurality of pixel electrodes arranged in a matrix form in the display region;

[0023] a light emitting layer connected to the plurality of pixel electrodes;

[0024] a controller configured to apply a pixel driving voltage to the plurality of pixel electrodes according to an image signal to cause the light emitting layer to emit light.

[0025] According to the implementation, the size of the touch driver for driving the touch sensor of the on-cell type or in-cell type touch panel display can be reduced.

[0026] According to a possible implementation of the first aspect, the random number generation unit generates the pseudo-random number using an m-sequence.

[0027] According to the implementation, since the pseudo-random number is generated using the m-sequence, the configuration of the touch driver can be simplified.

[0028] According to a possible implementation of the first aspect, the driving unit is mounted on an edge of the display region.

[0029] According to the implementation, the driving unit is mounted on a frame region of the display region. Since the size of the touch driver can be reduced, the size of the frame region can be reduced.

[0030] According to a possible implementation of the first aspect, the driving unit simultaneously drives a plurality of adjacent driving electrodes, and the detection unit detects the shape of the adjacent target object according to a detection signal output from the plurality of driving electrodes.

[0031] The implementation realizes the fingerprint authentication by simultaneously driving the plurality of adjacent driving electrodes for image recognition.

[0032] According to a possible implementation of the first aspect, the driving unit further includes an orthogonal variable spreading factor code generation unit configured to generate an orthogonal variable spreading factor code,

[0033] The controller selectively drives the plurality of drive electrodes according to the pseudo-random number generated by the random number generation unit and drives the plurality of drive electrodes according to the orthogonal variable spreading factor code generated by the orthogonal variable spreading factor code generation unit.

[0034] According to this implementation, a suitable drive electrode can be selected according to a touch panel mode or a fingerprint sensor mode.

[0035] With reference to a possible implementation of the first aspect, the controller drives the plurality of drive electrodes according to the pseudo-random number when detecting the adjacent target object in a part of the display area, and drives the plurality of drive electrodes according to the orthogonal variable spreading factor code when detecting the adjacent target object in the entire display area.

[0036] According to this implementation, a suitable CDM driving method can be selected according to a touch panel mode or a fingerprint sensor mode.

[0037] With reference to a possible implementation of the first aspect, the drive unit has a first transmission circuit for driving the plurality of drive electrodes in a coarse cycle and a second transmission circuit for driving the plurality of drive electrodes in a fine cycle.

[0038] According to this implementation, two transmission circuits with different periods can be selectively used according to an operation mode.

[0039] With reference to a possible implementation of the first aspect, the first transmission circuit is used for specifying a position of a finger, and the second transmission circuit is used for scanning a fingerprint of the specified finger.

[0040] According to this implementation, the position of the finger can be specified in a coarse cycle, and a fingerprint scan can be performed in the specified position in a fine cycle.

[0041] With reference to a possible implementation of the first aspect, the random number generator is used for generating pseudo-random numbers with different lengths according to an operation mode.

[0042] According to this implementation, the size of the random number is different between touch and fingerprint sensing.

[0043] With reference to a possible implementation of the first aspect, the detection unit performs code division multiplexing according to the detection signal.

[0044] According to this implementation, a CDM driving method can be performed according to a detection signal.

[0045] In a possible implementation of the first aspect, the sensor is formed in a display region on a substrate of the display device and is controlled by a circuit of the display device.

[0046] According to the implementation, the CDM driving method based on the pseudo-random number can be applied to a pixel driving circuit of a display device with an in-cell touch detection function.

[0047] In a possible implementation of the first aspect, the sensor includes a photodiode.

[0048] According to the implementation, the CDM driving method based on the pseudo-random number can be applied to a photodiode.

[0049] According to the second aspect, a method for driving an interactive display device is provided, the display device including:

[0050] a plurality of driving electrodes arranged in a display region on a substrate;

[0051] a plurality of detection electrodes for forming a sensor;

[0052] a detection unit for detecting a position of a neighboring target object according to a detection signal output from the plurality of detection electrodes;

[0053] a driving unit for selecting and driving the plurality of driving electrodes, the method including:

[0054] the driving unit generates a pseudo-random number;

[0055] a value of the pseudo-random number generated by the driving unit is shifted using a plurality of registers included in a shift register, the plurality of registers corresponding to the plurality of driving electrodes;

[0056] the driving unit drives the corresponding driving electrode according to the value of the pseudo-random number stored in the shift register.

[0057] According to the implementation, the driving electrode is driven according to the value of the pseudo-random number stored in the shift register. Therefore, the size of a touch driver for driving the touch sensor can be reduced.

[0058] In a possible implementation of the second aspect, the sensor is formed on a different plane from a substrate of the display device and is directly connected to a circuit of the display device.

[0059] In a possible implementation of the second aspect, the display region further includes:

[0060] a plurality of pixel electrodes arranged in a matrix form in the display region;

[0061] a light emitting layer connected to the plurality of pixel electrodes, wherein the method comprises:

[0062] applying pixel driving voltages to the plurality of pixel electrodes according to the image signal to cause the light emitting layer to emit light.

[0063] With reference to a possible implementation of the second aspect, generating the pseudo-random number comprises generating the pseudo-random number using an m-sequence.

[0064] With reference to a possible implementation of the second aspect, the driving unit simultaneously drives a plurality of adjacent driving electrodes, and the detecting unit detects the shape of the adjacent target object according to detection signals output from the plurality of driving electrodes.

[0065] With reference to a possible implementation of the second aspect, the method further comprises generating an orthogonal variable spreading factor code;

[0066] wherein the driving step comprises selectively driving the plurality of driving electrodes according to the pseudo-random number generated by the random number generating unit, and driving the plurality of driving electrodes according to the orthogonal variable spreading factor code generated by the orthogonal variable spreading factor code generating unit.

[0067] With reference to a possible implementation of the second aspect, the driving step drives the plurality of driving electrodes according to the pseudo-random number when detecting the adjacent target object in a part of the display area, and drives the plurality of driving electrodes according to the orthogonal variable spreading factor code when detecting the adjacent target object in the entire display area.

[0068] With reference to a possible implementation of the second aspect, the driving step comprises driving the plurality of driving electrodes in a coarse cycle or driving the plurality of driving electrodes in a fine cycle.

[0069] With reference to a possible implementation of the second aspect, the first driving step is used to specify the position of a finger, and the second driving step is used to scan the fingerprint of the specified finger.

[0070] With reference to a possible implementation of the second aspect, the generating step generates the pseudo-random numbers of different lengths according to an operation mode.

[0071] With reference to a possible implementation of the second aspect, the detecting comprises performing code division multiplexing according to the detection signals.

[0072] With reference to a possible implementation of the second aspect, the sensor is formed in a display area on a substrate of a display device, and is controlled by a circuit of the display device.

[0073] In a possible implementation form of the second aspect, the sensor comprises a photodiode. BRIEF DESCRIPTION OF DRAWINGS

[0074] In order to more clearly describe the technical solutions of the embodiments, the drawings needed for describing the embodiments will be briefly described below. Obviously, the drawings in the following description only describe some possible embodiments, and other drawings can be obtained by those of ordinary skill in the art without creative effort based on these drawings.

[0075] [ Figure 1 ] Figure 1 is a block diagram of a configuration of an interactive display device according to an embodiment.

[0076] [ Figure 2 ] Figure 2 is a perspective view of a configuration of a touch sensor.

[0077] [ Figure 3A ] Figure 3A is an equivalent circuit of a touch sensor.

[0078] [ Figure 3B ] Figure 3B is an equivalent circuit of a touch sensor.

[0079] [ Figure 4A ] Figure 4A is a potential waveform of a touch detection electrode (Rx).

[0080] [ Figure 4B ] Figure 4B is a potential waveform of a drive electrode (Tx).

[0081] [ Figure 5 ] Figure 5 is an edge structure of an on-cell type touch panel.

[0082] [ Figure 6 ] Figure 6 is an example of a basic operation of a CDM drive method.

[0083] [ Figure 7 ] Figure 7 is a configuration of a CDM drive signal generator according to a comparative example.

[0084] [ Figure 8A ] Figure 8A is an example of a 32-bit OVSF code.

[0085] [ Figure 8B ] Figure 8B is a diagram of a drive effect of a 32-bit CDM drive signal generator using an OVSF code.

[0086] [ Figure 9] Figure 9 is a perspective view of a configuration of an interactive display device according to an embodiment.

[0087] [ Figure 10 ] Figure 10 is a plan view of a configuration of an interactive display device according to an embodiment.

[0088] [ Figure 11 ] Figure 11 is an edge structure of an on-cell type touch panel according to an embodiment.

[0089] [ Figure 12 ] Figure 12 is a diagram of a configuration of a CDM code generator according to an embodiment.

[0090] [ Figure 13A ] Figure 13A is an example of a 32-bit m-sequence.

[0091] [ Figure 13B ] Figure 13B is a diagram of a driving effect of a CDM code generator using an m-sequence.

[0092] [ Figure 14 ] Figure 14 is a comparison table of image recognition results of an object having a striped groove.

[0093] [ Figure 15A ] Figure 15A is a relationship between an order of a CDM driving signal and a signal level measurement result.

[0094] [ Figure 15B ] Figure 15B is a relationship between an order of a CDM code and a signal-to-noise ratio (SNR).

[0095] [ Figure 16A ] Figure 16A is a diagram of an exemplary configuration of a sensor and an AFE.

[0096] [ Figure 16B ] Figure 16B is a diagram for explaining an operation of a capacitive element formed in a sensor.

[0097] [ Figure 17A ] Figure 17A is a diagram of an exemplary configuration of a touch driver.

[0098] [ Figure 17B ] Figure 17B is a diagram of an exemplary configuration of a touch driver.

[0099] [ Figure 17C ]Figure 17C is a diagram of an exemplary configuration of a touch driver.

[0100] [ Figure 18A ] Figure 18A is a diagram of an operation method of a touch driver.

[0101] [ Figure 18B ] Figure 18B is a diagram of an operation method of a touch driver.

[0102] [ Figure 18C ] Figure 18C is a diagram of an operation method of a touch driver.

[0103] [ Figure 18D ] Figure 18D is a diagram of an operation method of a touch driver.

[0104] [ Figure 19A ] Figure 19A is a diagram of a configuration of a display device according to an embodiment.

[0105] [ Figure 19B ] Figure 19B is a diagram of an exemplary configuration of a detection signal multiplexing unit and a CDM code generating unit.

[0106] [ Figure 20 ] Figure 20 is a diagram of a configuration example of an embodiment.

[0107] [ Figure 21 ] Figure 21 is a diagram of an example of performing CDM driving of a touch detection electrode (Rx).

[0108] [ Figure 22 ] Figure 22 is a flowchart of a process of a method of switching between a TP mode and an FPS mode.

[0109] [ Figure 23 ] Figure 23 An exemplary configuration of a display device according to an embodiment is shown. DETAILED DESCRIPTION

[0110] In order for those skilled in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments but not all the embodiments. According to the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the protection scope of the present application.

[0111] (First Embodiment)

[0112] Figure 1 is a block diagram of a configuration of an interactive display device according to the first embodiment. The interactive display device 1 includes a display device with touch detection function 100, a controller 106, gate drivers 116A and 116B (hereinafter sometimes abbreviated as gate drivers 116), a signal multiplexing unit (Sig-MUX) 108, a detection unit (Rx-MUX) unit 110, touch drivers 114A and 114B (hereinafter sometimes abbreviated as touch drivers 114), and a touch and display driver integration-integrated circuit (TDDI-IC) 112. The display device with touch detection function 100 is a display device incorporating a touch detection function. The display device with touch detection function 100 is an on-cell type electronic device in which a capacitive touch sensor 104 is mounted on a display device 102 using an organic light emitting diode (OLED) as a display element.

[0113] As will be described later, the display device 102 is a device that scans each horizontal line in order according to a scanning signal for display provided from the gate drivers 116. The controller 106 is a circuit that provides control signals to the touch drivers 114, the gate drivers 116, the signal multiplexing unit 108, the detection unit 110, and the TDDI-IC 112 according to image signals provided from the outside. The controller 106 controls these units so that they operate in synchronization with each other.

[0114] The gate drivers 116 have a function of selecting one or more horizontal lines to be driven for display on the display device with touch detection function 100 in order according to control signals provided from the controller 106.

[0115] The signal multiplexing unit 108 is a circuit that provides a pixel signal to each pixel of the display device 102 according to a control signal provided from the controller 106. The signal multiplexing unit 108 generates a time-division multiplexed pixel signal of a sub-pixel of the display device 102 from an image signal of one horizontal line. Further, the signal multiplexing unit 108 generates a switch control signal required for separating the multiplexed pixel signal.

[0116] The touch drivers 114 are circuits that provide a drive signal for touch detection to a drive electrode of the touch sensor 104 according to a control signal provided from the controller 106.

[0117] The detection unit 110 is a circuit for detecting the presence or absence of a contact state on the touch sensor 30 based on a control signal supplied from the controller 106 and a touch detection signal supplied from the touch sensor 104, and obtaining a coordinate in a touch detection area or the like when a touch is present. The detection unit 110 can amplify or multiplex the touch detection signal supplied from the touch sensor 104. Further, the detection unit 110 can include a low-pass analog filter that removes a high-frequency component (noise component) included in the touch detection signal to extract and output a touch component.

[0118] Figure 2 is a perspective view of a configuration of the touch sensor 104. The touch sensor 104 includes a drive electrode (Tx) 240 and a touch detection electrode (Rx) 234 facing the electrode pattern 238 through an insulator 230. The drive electrode (Tx) 240 configures an electrode pattern 238 extending in the horizontal direction of the drawing. When a touch detection operation is performed, Figure 4B The touch detection drive signal Vdrv shown is supplied to the electrode pattern 238 in order by the touch driver 114 so that the scan drive is performed in order on a time-sequential basis. The touch detection electrode (Rx) 234 configures an electrode pattern 235 extending in a direction crossing the extension direction of the electrode pattern of the drive electrode (Tx) 240. A single touch detection electrode (Rx) 234 is connected to the detection unit 110.

[0119] In the touch detection operation, when the touch driver 114 drives the drive electrode (Tx) 240 so as to scan the drive electrode (Tx) 240 in order in a time-division manner, the touch sensor 104 selects the horizontal lines in order. Also in the touch detection operation, the touch detection signal Vdet is output from the touch detection electrode (Rx) 234. Thus, scanning the entire electrode pattern 238 in the touch sensor 104 ensures detection of a position at which a finger or a hand 232 to be detected is in contact with or close to the touch sensor 104.

[0120] Next, the basic principle of touch detection in the touch sensor 104 will be described with reference to Figure 2 to FIG. 4. In Figure 2 , the touch sensor 104 is implemented as a capacitive touch sensor. The drive electrode (Tx) 240 and the touch detection electrode (Rx) 234 facing each other configure a capacitor. This structure is represented as Figure 3A the equivalent circuit shown. In Figure 3A , one end of the capacitor Cl is connected to an AC drive signal source through the drive electrode (Tx) 240, and the other end is connected to the TDDI-IC 216 through the touch detection electrode (Rx) 234. When an AC signal having a predetermined frequency is applied from the AC signal source to the drive electrode (Tx) 240, a phenomenon occursFigure 3A the power line Ef indicated by a broken line.

[0121] For example, when a detection target such as a finger does not contact or approach the touch sensor 104 as shown in Figure 3A , the current according to the capacitance of the capacitor Cl flows with charging or discharging of the capacitor Cl. For example, at this time, the waveform of the potential of the touch detection electrode (Rx) 234 stored in the capacitor Cl becomes Figure 4A the waveform V0 in

[0122] When the finger contacts or approaches the touch sensor 104, as shown in Figure 3B , the capacitor C2 formed by the finger is added in series to the capacitor Cl. In this state, different voltages are applied to the capacitors Cl and C2 according to charging or discharging of the capacitors Cl and C2, respectively. At this time, the power line Ef changes as indicated by a broken line in Figure 3B , so that the waveform of the potential of the touch detection electrode (Rx) 234 becomes Figure 4A the waveform V1 in . At this time, the potential of the touch detection electrode (Rx) 234 is a divided potential determined by the current flowing through the capacitors Cl and C2. Therefore, the value of the waveform V1 becomes smaller than the value of the waveform V0 in the non-contact state. The TDDI-IC 112 compares the detected voltage with a predetermined threshold voltage Vth and determines it as the non-contact state when the detected voltage is higher than the threshold voltage. Thus, it is possible to perform touch detection by detecting the change in capacitance in this way.

[0123] Next, the edge structure of an on-cell type touch panel will be described.

[0124] Figure 5An edge structure of an on-cell type touch panel according to a comparative example of the present embodiment is shown. The edge structure includes a gate driver 104, a conductive layer 504, a planarization layer 506, a thin film encapsulation (TFE) 512, a drive electrode (Tx) 240, an insulating layer 514, and a detection electrode (Rx) 234 and a passivation layer 516 laminated and disposed on a glass substrate 502. The gate driver 104 provides a signal to the display device 102 through the conductive layer 504. The planarization layer 506 is formed on the conductive layer 504 to form a flat plane on the upper side. A laminated structure of a conductive layer 518 and an inorganic layer 520 is disposed near the end portion of the planarization layer 506. The TFE 512 has a structure for sealing an OLED (not shown) and is formed by stacking an organic material layer 510 and an inorganic material layer 508. The drive electrode (Tx) 240 is formed on the TFE 512. The drive electrode (Tx) 240 is connected to the conductive layer 518 formed on the substrate 502. The insulating layer 514 is formed on the drive electrode (Tx) 240, and the touch detection electrode (Rx) 234 is formed on the insulating layer 514 at regular intervals. Further, the passivation layer 516 for protecting the touch panel is provided on the touch detection electrode (Rx) 234. As shown in Figure 2 , the longitudinal direction of the touch detection electrode (Rx) 234 is substantially orthogonal to the longitudinal direction of the drive electrode (Tx) 240.

[0125] Next, an example of a basic operation of a CDM driving method performed by the touch driver 114 will be described with reference to Figure 6

[0126] Referring to the example shown in Figure 6 , the touch driver of the interactive display device drives a drive electrode block including four drive electrodes Tx1, Tx2, Tx3, and Tx4. When the drive electrode block is driven by a time division multiplexing (TDM) method, signals having the same AC rectangular wave pattern are sequentially provided to the drive electrodes while their phases are shifted. When an object such as a finger contacts Tx2, a differential voltage is generated due to mutual induction. In Figure 6 , the change in the differential voltage is 20%. The value output from the touch detection electrode (Rx) is represented by a vector (1, 0.8, 1, 1). By applying the matrix (1) to this vector, a calculation result (1, 0.8, 1, 1) is obtained.

[0127]

[0128] ​In the case of the TDM driving system, the difference (sensitivity) between the output value of the detection signal at the position where the object does not contact and the output value of the detection signal at the position where the object contacts is 1 - 0.8 = 0.2.

[0129] In the CDM driving method, the drive electrode blocks are simultaneously selected, and an AC rectangular wave driving signal that determines the phase according to a predetermined code is provided. For example, the predetermined code is defined by a square matrix of the following equation (2), and the order of the square matrix is 4, i.e., the number of the driving electrodes Tx1, Tx2, Tx3, and Tx4 of the drive electrode blocks.

[0130]

[0131] The touch driver 114 provides the touch driving signal according to the square matrix of equation (2) so that the phase of the above-described AC rectangular wave corresponding to the component "-1" is an inverted signal of the signal corresponding to the diagonal component "1" of the square matrix.

[0132] When the target object contacts the driving electrode Tx2, the driving electrode Tx2 is the second position that is scanned upstream of the driving electrodes Tx1, Tx2, Tx3, and Tx4, and the touch detection signal output from the touch detection electrode during the first period is (3.8) + (0.2) + (-0.2) + (0.2) = 3.8. Next, the touch detection signal detected in the second period is (3.8) + (-0.2) + (-0.2) + (-0.2) = 3.2. Next, the touch detection signal detected in the third period is (3.8) + (0.2) - (-0.2) - (0.2) = 4. Next, the touch detection signal detected in the fourth period is (3.8) - (0.2) - (-0.2) + (0.2) = 4.

[0133] In the case of the CDM driving method, the difference (sensitivity) between the output value of the detection signal at the position where the object does not contact and the output value of the detection signal at the position where the object contacts is 4 - 3.2 = 0.8. Accordingly, the sensitivity is improved compared to the TDM driving method.

[0134] Figure 7A configuration of a CDM drive signal generator of a CDM drive system according to a comparative example of the present application is shown. The configuration shown in the figure generates orthogonal variable spreading factor (OVSF) codes from a series of orthogonal codes. In the CDM drive signal generator 1000, an 11-bit counter 1012 is connected to CDM code generators (CDM4) 1006A and 1006B and CDM code generators (CDM8) 1008A and 1008B. Each of the CDM code generators (CDM4) 1006A and 1006B is used to generate four CDM codes. When generating OVSF codes, the outputs of the CDM code generators (CDM4) 1006A and 1006B are XORed by an XOR calculator 1002 to generate 16 CDM codes. The CDM code generator 1004 includes 32 blocks of CDM code generators (CDM64). The CDM code generator 1004 generates 64 CDM codes from the outputs of the two CDM code generators (CDM8) 1008A and 1008B. Further, the 16 CDM codes of the XOR calculator and the 64 CDM codes of the CDM code generator 1004 are input into an XOR operator (CDM1024) 1010. The XOR operation is performed by the XOR operator (CDM1024) 1010 to generate 1024 CDM codes, which are output to a buffer 1018.

[0135] Figure 8A is an example of a 32-bit OVSF code. In the figure, each row represents a 32-bit CDM code generated from an OVSF code and provided to a drive electrode (Tx). Here, "P" represents 1 and "N" represents -1.

[0136] Figure 8B is a graph of drive effects of a 32-bit CDM drive signal generator using OVSF codes.

[0137] The three-dimensional graph in the figure shows output values of detection signals in a case where detection of a fingerprint is performed by simulation using simulated fingerprint data. The vertical axis of the graph represents the intensity of the output values, the horizontal axis shows the positions of the touch detection electrodes (Rx), and the axis in the depth direction shows the positions of one touch detection electrode (Rx). In the pseudo fingerprint data, the output voltage difference between the position where the finger is in contact and the position where the finger is not in contact is 20% (0.2). In this case, according to the drive in the TDM drive method, the difference (sensitivity) between the signal output value at the position where the finger is in contact and the signal output value at the position where the finger is not in contact is 0.2. On the other hand, in the CDM drive signal generator using OVSF codes, the difference between the signal output value at the position where the finger is in contact and the signal output value at the position where the finger is not in contact is 6. This value is 32 times the value in the TDM drive system.

[0138] As described above, the CDM driving method using the OVSF code has higher sensitivity than the TDM driving method. This function is implemented on a touch sensor control device (TP-IC) provided outside the substrate, so that the TP-IC transmits a driving signal to the driving electrode (Tx) from the outside. However, in order to increase the order of the OVSF code, a complex structure is required. Therefore, the size of the CDM driving signal generator generating the OVSF code is greatly dependent on the order of the CDM driving signal.

[0139] In the present embodiment, by simplifying the configuration of the driving circuit of the touch sensor, the driving circuit can be installed in a narrow frame area on the substrate.

[0140] Figure 9 and Figure 10 are a perspective view and a plan view, respectively, showing the configuration of an interactive display device according to the present embodiment. In the display device 100 having a touch detection function, a rectangular display area is provided at the center of the substrate 602. As shown in Figure 10 , the gate driver 116A and the touch driver 114A are provided on one side of the display area, and the gate driver 116B and the touch driver 114B are provided on the other side thereof. Further, the signal multiplexing unit 108, the detection unit 110, and the TDDI-IC 112 are provided below the display area.

[0141] In Figure 9 , the pixel driving circuit 702 for driving a pixel is provided in an N×M matrix format using a thin film transistor (TFT) in the display area. The OLED 704 is formed on the pixel driving circuit 702. The OLED 704 is a light emitting layer provided between a pixel electrode and a driving electrode included in the pixel driving circuit 702, and emits light when driven by the pixel driving circuit 702. Therefore, the pixel driving circuit 702 and the OLED 704 form the display device 102. The gate driver 116 applies a pixel driving voltage to the pixel driving electrode and the driving electrode 702 according to an image signal, to cause the light emitting layer to emit light. The OLED 704 is sealed by the TFE 612. The driving electrode (Tx) 640 and the touch detection electrode (Rx) 634 are provided on the TFE 612. As indicated by the curved arrow, a driving signal generated by the touch driver 114 is supplied to the driving electrode (Tx) 640. A signal from the touch detection electrode (Rx) 634 is supplied to the detection unit 110.

[0142] Figure 11 shows the edge structure of an on-cell type touch panel, which corresponds to Figure 9An x-x' cross-sectional view of the display device is shown. In the edge structure, the gate driver 116 and the touch driver 114 are formed side by side on the glass substrate 602, and the conductive layer 604, the planarization layer 608, the TFE 612, the drive electrode (Tx) 240, the insulating layer 614, the touch detection electrode (Rx) 634, and the passivation layer 616 are further formed by lamination thereon. The gate driver 116 is used to provide a signal to the display device 102 through a metal wire (not shown). The touch drivers 114A and 114B drive the touch sensor 104 by the CDM driving method. The touch driver 114A includes a CDM code generator 118A and a buffer 120A. The touch driver 114B also includes a CDM code generator 118B and a buffer 120B. The CDM code generators 118A and 118B generate a CDM code signal (a driving signal) for CDM driving. The buffers 120A and 120B store and provide the CDM code to the drive electrode (Tx) 640. The planarization layer 606 is formed on the conductive layer 604 to form a flat plane on the upper side thereof. The inorganic layer 620 is formed near the end portion of the planarization layer 606. The TFE 612 has a structure for sealing an OLED (not shown) and is formed by stacking an organic material layer 610 and an inorganic material layer 608.

[0143] In one embodiment, an epoxy resin can be used for the organic material layer 610. For the inorganic layers 620 and 608, silicon nitride or aluminum oxide, etc. can be used. Although the TFE 612 has only a two-layer structure of the organic layer 610 and the inorganic layer 608 in Figure 11 , it can have a three-layer or more structure. The drive electrode (Tx) 640 is formed on the TFE 612. The drive electrode (Tx) 640 is connected to the conductive layer 604. The insulating layer 614 is provided on the drive electrode (Tx) 640, and the touch detection electrode (Rx) 634 is formed on the insulating layer 614 at regular intervals. Further, the passivation layer 616 for protecting the touch panel is provided on the touch detection electrode (Rx) 634. For the passivation layer 616, a photosensitive polyimide, polybenzoxazole (PBO), or a silicon-based resin material is used. As shown in Figure 9 , the longitudinal direction of the touch detection electrode (Rx) 634 is substantially orthogonal to the longitudinal direction of the drive electrode (Tx) 640.

[0144] The drive electrode (Tx) 640 and the touch detection electrode (Rx) 634 constitute a touch sensor. The touch sensor is formed on the display device, on a different plane from the substrate 602 of the TFT circuit for the display device 102, and is directly connected to the TFT circuit. The drive electrode (Tx) 640, the touch detection electrode (Rx) 634, and the conductive layer 604 can be composed of a metal such as silver (Ag), gold (Au), copper (Cu), or molybdenum (Mo). When the touch sensor is driven by the CDM driving method in this configuration, the touch driver 114 supplies a drive signal to the drive electrode (Tx) 640 through the conductive layer 604, as indicated by the arrow.

[0145] Next, executable functions in the interactive display device will be described. The electronic device such as a smartphone currently in use can have a drive electrode (Tx) and a touch detection electrode (Rx) layout such that the FPS can be executed in the display area. In the interactive display device, the capacitance difference between the detection operation of the touch panel (TP) and the detection operation of the fingerprint authentication (FPS) is different.

[0146] In the case of the conventional detection operation of the TP, if the distance between the drive electrode (Tx) and the touch detection electrode (Rx) is 4 mm, and if the distance between the touch detection electrode (Rx) and the finger is about 1 mm, the object should be detected. In this case, the capacitance difference between the position where the finger touches and the position where the finger does not touch can be about 100 fF.

[0147] On the other hand, in the case of the FPS detection operation, it is necessary to detect the difference between the valleys and the ridges of the fingerprint, and thus a very high sensitivity is required. For example, when the distance between the drive electrode (Tx) and the touch detection electrode (Rx) is 50 μm, and the distance between the touch detection electrode (Rx) and the finger is about 200 μm, the fingerprint authentication can be performed. In this case, the capacitance difference between the position where the finger contacts and the position where the finger does not contact is about 100 aF. This value is 1 / 1000 of the capacitance difference used by the TP. When the fingerprint authentication is performed in this configuration, some of the drive electrodes (Tx) where the finger contacts can be grouped. On the other hand, the detection operation of the touch panel (TP) can be performed by selecting the drive electrode (Tx) from each of all the touch detection electrode groups.

[0148] Figure 12is a diagram of the configuration of the CDM code generator 118 according to the present embodiment. The CDM code generator 118 includes an m-sequence generator 1102 as a random number generator, a CDM drive signal generator 1104, and a buffer 120. The drive unit 118 includes the m-sequence generator 1102 for generating a pseudo-random number and a shift register 1104 having a register for shifting each bit of the pseudo-random number. Each register corresponds to each drive electrode (Tx) 640. The drive unit 118 drives the corresponding drive electrode according to the pseudo-random number value stored in the plurality of registers.

[0149] The m-sequence generation unit 1102 generates an m-sequence (maximum length sequence) signal. The m-sequence generation unit 1102 has a 10-stage shift register, and a tap position is provided at the third stage. When the length of the shift register is m, and the number of registers until the tap position is n, the length of the m-sequence length is represented by 2 n -1. The m-sequence signal is a binary (0 and 1 or -1 or 1) periodic signal used as a spread code or a pseudo-noise code. Since the m-sequence signal is a periodic signal, if the initial value of one period is known, the values of all sequences can be known. Further, the m-sequence has good properties as a random number within one period.

[0150] The shift register 1104 shifts the values in order according to the input of the clock signal (Clk) from the controller 106, performs an XOR operation on the output of the tenth stage and the output of the third stage, and returns the result to the first stage. The CDM drive signal generation unit 1104 has a shift register of 1023 stages, stores the output from the m-sequence generation unit 1102 in the shift register in order, and stores it in the buffer 120.

[0151] The size of the CDM code generator 118 using the m-sequence does not depend seriously on the order of the CDM drive signal. Therefore, by configuring the CDM drive signal generator 1104 as Figure 12 indicated, it is possible to reduce the size of the CDM code generator. Therefore, it is possible to reduce the size of the frame area in which the CDM code generator 118 is installed.

[0152] Figure 13A is an example of a 32-bit m-sequence. In the figure, each row represents a 32-bit CDM code generated according to the m-sequence and provided to the drive electrode (Tx). Here, "P" represents 1, and N represents -1. Figure 13Bis a graph of the driving effect of a CDM code generator using an m-sequence. As can be clearly seen from the graph, the CDM driving signal generator uses an m-sequence, and the difference between the signal output value of the position where the finger is in contact and the signal output value of the position where the finger is not in contact is 6.4. That is, the CDM driven using an m-sequence has the same sensitivity as when OVSF is used.

[0153] Figure 14 A comparison table of the image recognition results of an object having a striped groove using a TDM driving method, a CDM driving method using 128 CDM codes (CDM128), a CDM driving method using 256 CDM codes (CDM256), and a driving method using 512 CDM codes (CDM512) is shown. The first row shows the type of the method of driving the detection signal (TDM, CDM128, CDM 256, and CDM 512). The image in the second row of the table shows the image generated from the detection signal. Further, the graph in the third row of the table shows the image of the cross section of the groove portion predicted from the generated image. The fourth row shows the signal intensity, the noise intensity, and the signal-to-noise ratio (SNR). As can be seen from the table, the CDM driving method can detect unevenness with higher sensitivity than the TDM driving method. Further, the higher the order of the CDM code, the better the sensitivity.

[0154] Figure 15A The relationship between the order of the CDM driving signal and the signal level measurement result is shown. According to the theoretical value of the signal level, the signal level is proportional to the order of the CDM code. Further, Figure 15B The relationship between the order of the CDM code and the signal-to-noise ratio (SNR) is shown. The theoretical value of the SNR is also proportional to the order of the CDM driving signal. These graphs show that the measured values of the actual signal and the SNR are close to the theoretical values.

[0155] Next, the configuration of the TDDI-IC will be described. The TDDI-IC integrates a narrowband analog frontend (AFE). The AFE is an analog circuit that connects a sensor for detecting a signal and a device for digital signal processing, and the like. Figure 16A is a graph of an exemplary configuration of one of the sensors provided in the touch sensor and the AFE connected to the sensor. In the sensor 1602, a drive electrode (Tx) and a touch detection electrode (Rx) form a capacitance Cm. A signal of an AC voltage Vtx=20 V is supplied to the drive electrode (Tx). A signal corresponding to the change ΔCm of the capacitance is output from the touch detection electrode (Rx) to the AFE 1600. Figure 16Bis a diagram for explaining the operation of a capacitive element formed in the sensor 1602. When a finger approaches the sensor, the distance from the sensor 1602 to the ridge of the fingerprint is different from the distance from the sensor 1602 to its valley. Accordingly, the sensor 1602 can form different capacitances in the ridge and the valley of the finger, and can calculate the shape of the fingerprint according to the capacitance difference. In the fingerprint authentication, adjacent drive electrodes are grouped and driven at the same time so as to calculate the shape of the finger approaching the touch sensor.

[0156] Referring again to Figure 16A , the AFE 1600 includes an integrator 1604, a gain amplifier (AMP) 1606, and an analog / digital converter (ADC) 1608. The integrator 1604 includes an operational amplifier and a capacitor Cfb, and uses an output value Vtx from the sensor 1602 as an input, to provide an output voltage Vout = Vtx(Cm / Cfb) to the gain amplifier 1606. The gain amplifier 1606 includes an operational amplifier and two resistors Rin and Rf. It inverts and amplifies Vout to output an output voltage Vgain = Vtx(Rf / Rin). The ADC 1608 inputs the analog output voltage Vgain to generate a digital output.

[0157] As described above, according to the present embodiment, a shift register including registers respectively corresponding to the drive electrodes is provided, and a random number generator for generating a pseudo-random number having bits respectively corresponding to the plurality of registers is provided. Further, a controller for driving the corresponding drive electrodes according to the values of the shift register is provided. With this configuration, the size of the CDM code generator can be reduced. Accordingly, the size of the frame area in which the CDM code generator is mounted can be reduced.

[0158] (Second Embodiment)

[0159] Next, a second embodiment of the present application will be described. In the present embodiment, the touch driver performs operations by switching between two modes, a touch panel scan mode (TP mode) and a fingerprint authentication mode (FPS mode).

[0160] Figure 17A to Figure 17C A diagram showing an exemplary configuration of the touch driver 114 is shown. In Figure 17AIn the middle, the touch driver 114 includes a CDM drive signal generator 1704 driven by a clock signal (Clk), a reset signal (Rst), or a start pulse signal (St), CDM shift register blocks (CDM SR blocks) 1702A, 1702B,..., 1702M-1, and 1702M (hereinafter, they can be simply referred to as CDM SR blocks 1702) connected to the drive electrodes (Tx), and an m-sequence generator 1102. Here, the start pulse signal (St) is according to the H / L signal of the code. The CDM SR blocks 1702A, 1702B,..., 1702M-1, and 1702M are connected to selectors 1706A, 1706B,..., 1706M-1, and 1706M (hereinafter, simply referred to as selectors 1706). The selectors 1706 are connected to the m-sequence generator 1102 and a TP mode selection line 1712. In addition, each selector is connected to one of shift registers 1708A, 1708B,..., 1708M-1, and 1708M (hereinafter, simply referred to as shift registers 1708). These shift registers are used to shift the stored values according to the clock signal (Clk), the reset signal (Rst), or the start pulse signal (St).

[0161] Figure 17B is included in Figure 17A An enlarged view of the portion surrounded by the circle 1710 in the middle, and shows the operation of the portion in the TP mode. The selector 1706A is composed of two AND circuits 1706A-1 and 1706A-2. One AND circuit 1706A-2 is connected to the shift register 1708A and the TP mode selection line 1715, and the other AND circuit 1706A-1 is connected to the AND circuit 1714 and the output of the shift register 1708A. The input of the AND circuit 1714 is connected to the m-sequence generator 1102 and the FPS mode selection line 1716. The selector 1706B has the same structure.

[0162] The CDM SR block 1702A includes shift registers 1702A-1, 1702A-2,..., 1702A-n, the input of each shift register is connected to the AND circuit 1706A-1, and the output is connected to an OR circuit 1703A-1. One input of the OR circuit 1703A-1 is connected to the AND circuit 1706A-1, and the other input is connected to the shift register 1702A-1. The output of the OR circuit 1703A-n is connected to one drive electrode (Tx).

[0163] In TP mode, the TP mode selection signal is provided from TP mode selection line 1712. For example, this signal can be provided from controller 106. The OR circuit 1706A-2 outputs the value of shift register 1708A to OR circuits 1703A-1, 1703A-2…1703A-n. The OR circuits 1703A-1, 1703A-2…1703A-n output the values ​​of shift registers 1702A-1, 1702A-2…1702A-n to all drive electrodes (Tx) connected to CDM SR block 1702A, respectively.

[0164] The next CDM SR block 1702B also performs the same process. Similarly, the drive electrode (Tx) is driven for the remaining CDM SR blocks 1702.

[0165] Figure 17C It includes Figure 17A An enlarged view of the portion enclosed by circle 1710 is shown, illustrating its operation in FPS mode. In FPS mode, the FPS mode signal is provided to AND circuit 1714. AND circuit 1714 provides the signal (CDM code) from m-sequence generator 1102 to AND circuit 1706B-1. AND circuit 1706B-1 provides the value generated by m-sequence generator 1102 to shift registers 1702B-1, 1702B-2...1702B-n of CDM SR block 1702B selected by shift register 1708B. The values ​​of shift registers 1702B-1, 1702B-2...1702B-n are then provided to the drive electrode (Tx) via OR circuits 1702B-1, 1702B-2...1702B-n.

[0166] Therefore, according to the example shown in Figure 17, the touch driver 114 has two transmission circuits with different cycles. One circuit in Figure 17B As shown, it performs a scan in a coarse loop, while another circuit... Figure 17C As shown, it performs a scan in a fine loop. Then, a touch scan is performed in a coarse loop, and a fingerprint scan is performed in a fine loop.

[0167] Therefore, the position of the finger can be specified in a coarse loop, and the fingerprint scan can be performed at the specified position in a fine loop.

[0168] Figure 18A to Figure 18D This is a diagram illustrating the operation of the touch driver 114 according to an embodiment. In this embodiment, there are two TP modes: the TP mode shown in FIG. 17 (TP mode 1) and the TP mode using the m-sequence generator (TP mode 2).

[0169] Figure 18A An exemplary configuration of the CDM code generator is shown.Figure 18A In this circuit, the m-sequence generator 1102 has inputs from the TP mode 1 select line (TP mode 1), the TP mode 2 select line (TP mode 2), the FPS mode select line (FPS mode), and the set line (St). The TP mode 1 select line and the TP mode 2 select line are connected to the OR circuit 1804 before the m-sequence generator 1102. The output of the OR circuit 1804 is connected to the OR circuits 1706A-2 and 1706B-2, such that the value of the shift register 1708A or 1708B can be output to the CDM SR block 1702A or 1702B in either TP mode 1 or TP mode 2.

[0170] Then, refer to Figure 18B to Figure 18C Describe each operation of the m-sequence generator 1102 in TP mode 1, TP mode 2 and FPS mode.

[0171] Figure 18B The operation of the m-sequence generator 1102 in TP mode 1 is shown. For example... Figure 18B As shown, the m-sequence generator 1102 has three AND circuits 1802A, 1802B, and 1802C. Signal TP_mode1 and signal St are input to AND circuit 1802C. Then, AND circuit 1802C outputs the signal to OR circuit 1806, and OR circuit 1806 outputs signal TP_st to shift register 1708A.

[0172] Figure 18C The operation of the m-sequence generator 1102 in TP mode 2 is shown. For example... Figure 18C As shown, the m-sequence generator 1102 has two switches, SW1 and SW2, which are turned on / off by signals from the TP mode 2 selection line and the FPS mode selection line, respectively. The m-sequence generator 1102 can switch the tap position between the TP mode 2 case and the FPS mode case.

[0173] exist Figure 18C In the example shown, switch SW1 is turned on by a signal applied from the TP mode 2 select line, and the drive mode is switched to TP mode 2. In this case, the tap position is located between the first and second stages of the shift register. On the other hand, in Figure 18D In the example shown, switch SW1 is turned off by a signal applied from the TP mode 2 select line, and switch SW2 is turned on by a signal applied from the FPS mode select line. In this case, the tap position is located between the third and fourth stages of the shift register. When the shift register length is m, and the number of shift registers up to the tap position is n, the length of the m sequence is 2. n -1 indicates that, therefore, by using the above configuration, the length of the m-sequence in FPS mode can be increased, while simultaneously driving the adjacent driving electrodes (Tx) included in the driving electrode block.

[0174] According to the example in FIG. 18, therefore, the m-sequence generator 1102 also has a function of generating a random number of which the length varies depending on the operation mode.

[0175] Accordingly, the size of the random number differs between the touch and the fingerprint recognition.

[0176] (Third Embodiment)

[0177] Next, a third embodiment of the present application will be described, in which code division multiplexing is performed on the output signal from the touch detection electrode (Rx).

[0178] Figure 19A is a diagram of the configuration of a display device according to the present embodiment. In the present embodiment, the detection unit 110 is replaced by a detection signal multiplexing unit 1912 and a CDM code generation unit 1902 as a function of receiving the touch detection electrode (Rx). The detection signal multiplexing unit 1912 performs code division multiplexing on the output signal from the touch detection electrode (Rx). The CDM code generation unit 1902 supplies a CDM code to the detection signal multiplexing unit 1912.

[0179] Figure 19B is a diagram of an exemplary configuration of the detection signal multiplexing unit 1912 and the CDM code generation unit 1902. It is assumed that seven adjacent touch detection electrodes (Rx) are used as the touch detection electrodes (Rx) for the fingerprint authentication. In the present example, the signals of the seven touch detection electrodes (Rx) are denoted by SigO to Sig6 from the right side. SigO to Sig6 are connected to the sources of transistors T00, T10, T20, T30, T40, T50, and T60, respectively. In addition, SigO to Sig6 are also connected to the sources of transistors T01, T11, T21, T31, T41, T51, and T61, respectively.

[0180] The gates of the transistors T00, T10, T20, T30, T40, T50, and T60 are connected to each stage of a shift register 1908. In addition, the gates of the transistors T01, T11, T21, T31, T41, T51, and T61 are connected to each stage of a shift register 1916.

[0181] The drains of the transistors T00, T10, T20, T30, T40, T50, and T60 are connected to an Rx reading unit (RxO) 1910. The drains of the transistors T01, T11, T21, T31, T41, T51, and T61 are connected to an Rx reading unit (Rx1) 1909.

[0182] According to the above configuration, when the value output from the m-sequence generator is 0, the outputs of Sig0 to Sig6 are multiplexed by the Rx reading unit (Rx0) 1910. In addition, when the value output from the m-sequence generator is 1, the outputs of Sig0 to Sig6 are multiplexed by the Rx reading unit (Rx1) 1909.

[0183] Figure 20 is a diagram of another configuration example of the present embodiment. For example, when the fingerprint authentication is performed in a range of a length (50 μm x 255 Tx) of 12.5 mm and a width (50 μm x 259 Rx) of 13 mm, the detection signal multiplexing unit 1912 needs 37 multiplexing groups of touch detection electrodes (Rx), in which the outputs of 7 touch detection electrodes (Rx) are multiplexed in each group. In addition, the touch driver 114 is used to generate 255 CDM codes using the m-sequence generator including an eight-stage shift register.

[0184] Figure 21 is a diagram of an example of performing CDM driving of the touch detection electrodes (Rx). The horizontal direction of the graph shows the CDM driving of the drive electrodes (Tx). Here, in four periods of t1, t2, t3, and t4, the CDM driving of the drive electrodes (Tx) is performed on the four drive electrodes (Tx) Tx1 to Tx4.

[0185] The vertical direction in the figure shows CDM driving of the touch detection electrodes (Rx). Here, CDM driving of the touch detection electrodes (Tx) is performed on the four touch detection electrodes (Rx) Rx1 to Rx4. Read(+) indicates a read value of the Rx read unit (Rx1) 1909. Read(-) indicates a read value of the Rx read unit (Rx0) 1910. In the CDM driving of the touch detection electrodes (Rx), each of the four periods t1 to t4 is further divided. For example, the period t1 is divided into four periods t11, t12, t13, and t14. At t11, the Rx read unit (Rx1) 1909 receives values of Rx1 to Rx4. At t12, the Rx read unit (Rx0) 1908 receives values of Rx1 and Rx3, and the Rx read unit (Rx0) 1910 receives values of Rx2 and Rx4. At t13, the Rx read unit (Rx1) 1909 receives values of Rx1 and Rx2, and the Rx read unit (Rx0) 1910 receives values of Rx3 and Rx4. At t14, the Rx read unit (Rx1) 1909 receives values of Rx1 and Rx4, and the Rx read unit (Rx0) 1910 receives values of Rx2 and Rx3. Similar processing is performed in the periods t2 to t4. That is, the period t2 is also divided into t21, t22, t23, and t24. The period t3 is also divided into t31, t32, t33, and t34. Further, the period t4 is divided into t41, t42, t43, and t44.

[0186] By performing such processing, adjacent drive electrodes (Tx) can be grouped to perform CDM driving, and adjacent touch detection electrodes (Rx) can be grouped to perform CDM driving. Further, even if the distance between the drive electrodes (Tx) is small or the distance between the touch detection electrodes (Rx) is small, the detection sensitivity can be improved.

[0187] Figure 22 is a flowchart of a process of a method of switching between a TP mode and an FPS mode performed in a display device according to an embodiment. For example, the method can be performed by the controller 106. In step S1, the controller 106 performs CDM driving in a TP mode. In step S2, the controller 106 determines whether an FPS mode selection signal has been received. When the FPS mode selection signal is received in step S2, the process proceeds to step S3. In step S3, the controller 106 selects a display area according to data from an application requesting fingerprint authentication and data output from the touch panel. In step S4, the controller 106 drives the touch sensor in an FPS mode.

[0188] (Fourth Embodiment)

[0189] In the above-described embodiment, the capacitive touch sensor is described as an example of a sensor driven by the CDM driving method. However, in the present embodiment, an optical sensor such as a photodiode (PD) can be used as a sensor driven by the CDM driving method, instead of a capacitive touch sensor. For example, in the case of a PD, it is formed in a display region on the substrate 602 of the display device 100 and is controlled by a TFT circuit.

[0190] Figure 23 An exemplary configuration of a display device according to the present embodiment is shown. As shown in the example shown in the drawing, the sensor includes a PD. The present application can be applied to a pixel driving circuit of a display device having an in-cell touch detection function. The pixel driving circuit shown in the drawing includes a 7T1C circuit including seven transistors and one capacitor for driving an OLED. Further, the pixel driving circuit includes a photodiode (PD) driving circuit including transistors for driving a photodiode PD to detect an adjacent target object. The PD is driven by applying a voltage to a driving electrode to detect light and outputs a detection signal to a vertical detection electrode. The pixel driving circuit shown in the drawing has a large number of transistors and capacitors, and the circuit is complex, so there is little space to include an additional component. Therefore, there is a problem that an amplifier transistor cannot be added to improve the detection sensitivity of the photodiode. Therefore, the circuit does not have an amplifier for the PD. By using a CDM code generator including an m-sequence generator as a touch sensor in combination with such a configuration, the detection sensitivity can be improved without increasing the amplifier transistor.

[0191] The above description is merely a specific implementation of the present application and is not intended to limit the scope of protection of the present application. Changes or substitutions within the scope of the disclosed technology that are easily conceivable by those skilled in the art should be encompassed within the scope of protection of the present application. Therefore, the scope of protection of the present application should be determined by the scope of protection of the claims.

Claims

1. An interactive display device, characterized by The display device includes: a plurality of drive electrodes disposed in a display region on a substrate; a plurality of detection electrodes for forming a sensor; a detection unit for detecting a position of an adjacent target object based on a detection signal output from the plurality of detection electrodes; a drive unit for selecting and driving the plurality of drive electrodes; wherein the drive unit includes: a random number generator for generating a pseudo-random number using an m-sequence; a shift register having a plurality of registers for shifting values of the pseudo-random number generated by the random number generator, the plurality of registers corresponding to the plurality of drive electrodes; a controller for driving the corresponding drive electrodes based on the values of the pseudo-random number stored in the plurality of registers; the drive unit has a first transmission circuit for driving the plurality of drive electrodes in a coarse cycle and a second transmission circuit for driving the plurality of drive electrodes in a fine cycle, wherein the first transmission circuit is for an operation mode of specifying a position of a finger, the second transmission circuit is for an operation mode of scanning a fingerprint of the specified finger, and the random number generator in the transmission circuit generates pseudo-random numbers of different lengths according to different operation modes.

2. The interactive display device of claim 1, wherein, The sensor is formed on a different plane from the substrate of the display device and is directly connected to the circuit of the display device.

3. The interactive display apparatus of claim 1 or 2, wherein, Further comprising: a plurality of pixel electrodes disposed in a matrix form in the display region; a light emitting layer connected to the plurality of pixel electrodes; a controller for applying a pixel drive voltage to the plurality of pixel electrodes based on an image signal to cause the light emitting layer to emit light.

4. The interactive display apparatus of claim 1 or 2, wherein, The drive unit is mounted on an edge of the display region.

5. The interactive display apparatus of claim 1 or 2, wherein, The drive unit simultaneously drives a plurality of adjacent drive electrodes, and the detection unit detects a shape of the adjacent target object based on a detection signal output from the plurality of drive electrodes.

6. The interactive display apparatus of claim 1 or 2, wherein, The drive unit further includes a orthogonal variable spreading factor code generation unit for generating an orthogonal variable spreading factor code, wherein the controller selectively drives the plurality of drive electrodes based on the pseudo-random number generated by the random number generation unit and drives the plurality of drive electrodes based on the orthogonal variable spreading factor code generated by the orthogonal variable spreading factor code generation unit.

7. The interactive display device of claim 6, wherein, The controller drives the plurality of drive electrodes based on the pseudo-random number when detecting the adjacent target object in a portion of the display region, and the controller drives the plurality of drive electrodes based on the orthogonal variable spreading factor code when detecting the adjacent target object in the entire display region.

8. The interactive display apparatus of claim 1 or 2, wherein, The detection unit performs code division multiplexing based on the detection signal.

9. The interactive display apparatus of claim 1 or 2, wherein, The sensor is formed in a display region on a substrate of a display device and is controlled by a circuit of the display device.

10. The interactive display apparatus of claim 1 or 2, wherein, The sensor includes a photodiode.

11. A method for driving an interactive display device, characterized by, The display device includes: a plurality of drive electrodes disposed in a display region on a substrate; a plurality of detection electrodes for forming a sensor; a detection unit for detecting a position of an adjacent target object based on a detection signal output from the plurality of detection electrodes; a drive unit for selecting and driving the plurality of drive electrodes, the method comprising: the drive unit generating a pseudo-random number using an m-sequence; shift the value of the pseudo-random number generated by the driving unit using a plurality of registers included in a shift register, the plurality of registers corresponding to the plurality of driving electrodes; the driving unit drives the corresponding driving electrode according to the value of the pseudo-random number stored in the shift register; the driving the plurality of driving electrodes includes a first driving step of driving the plurality of driving electrodes in a coarse cycle, or a second driving step of driving the plurality of driving electrodes in a fine cycle, wherein the first driving step is used for an operation mode of specifying the position of a finger, the second driving step is used for an operation mode of scanning the fingerprint of the specified finger, and the generating step generates pseudo-random numbers of different lengths according to different operation modes.

12. The method of claim 11, wherein, The sensor is formed on a display area of a substrate of a display device and is directly connected to a circuit of the display device.

13. The method according to claim 11 or 12, characterized in that, The display area further includes: a plurality of pixel electrodes arranged in a matrix in the display area; a light emitting layer connected to the plurality of pixel electrodes, wherein the method includes: applying pixel driving voltages to the plurality of pixel electrodes according to an image signal to cause the light emitting layer to emit light.

14. The method of claim 11 or 12, wherein, The driving unit simultaneously drives a plurality of adjacent driving electrodes, and the detecting unit detects the shape of the adjacent target object according to detection signals output from the plurality of driving electrodes.

15. The method of claim 11 or 12, wherein, further including generating an orthogonal variable spread factor code, wherein the driving the plurality of driving electrodes further includes selectively driving the plurality of driving electrodes according to the pseudo-random number generated by a random number generating unit and driving the plurality of driving electrodes according to the orthogonal variable spread factor code generated by an orthogonal variable spread factor code generating unit.

16. The method of claim 15, wherein, driving the plurality of driving electrodes according to the pseudo-random number when detecting the adjacent target object in a portion of the display area, and driving the plurality of driving electrodes according to the orthogonal variable spread factor code when detecting the adjacent target object in the entire display area.

17. The method of claim 11 or 12, wherein, The detecting the position of the adjacent target object according to the detection signals output from the plurality of detection electrodes includes performing code division multiplexing according to the detection signals.

18. The method of claim 11 or 12, wherein, The sensor is formed in a display area on a substrate of a display device and is controlled by a circuit of the display device.

19. The method of claim 18, wherein, The sensor includes a photodiode.

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