Display apparatus with touch panel and control method thereof

Abstract

To provide a display apparatus with a touch panel and a control method thereof capable of preventing a touch detection process started within a first period of the first period and a second period constituting one frame period from affecting a process performed within the second period, while preventing a period in which touch is detected from being extended even when operating at a variable frame rate.SOLUTION: A display apparatus 100 with a touch panel starts first touch detection process within an extended period and ends the first touch detection process before a normal driving period begins. The display apparatus 100 with the touch panel performs a process of outputting first report data when the length of the extended period is a predetermined length or longer. After the normal driving period begins, the display apparatus 100 with the touch panel performs second touch detection process, a writing process, and a process for outputting the second report data.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a display device with a touch panel and a control method thereof. [Background technology]

[0002] Patent Document 1 describes a display device with a touch panel. This display device with a touch panel includes a display unit, a detection unit, and a control unit. The display unit performs a display operation for displaying an image. The detection unit performs a touch detection operation for detecting a detection signal corresponding to an external nearby object in a touch detection period that is a period different from the normal drive period in which the display operation is performed. One frame period in which one frame of image is displayed includes a normal drive period, a touch detection period, and a display adjustment period for adjusting the display of the image. The control unit performs a touch detection operation in the display adjustment period when one frame period is driven at a low speed of 33.3 ms (30 Hz), which is a predetermined period longer than 16.6 ms (60 Hz) that is the length during normal drive. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-60319 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, there is a demand for a display device with a touch panel that operates at a variable frame rate where the length of one frame period varies, rather than just two types of frame period, one frame period during normal driving and one frame period during low-speed driving, and a control method thereof.In this case, one frame period includes a period whose length varies (hereinafter referred to as a "first period"), and a period in which normal driving is performed after the first period (hereinafter referred to as a "second period").

[0005] However, in a display device with a touch panel that operates at a variable frame rate, if the length of the first period is short, the second period starts while the touch detection operation that started during the first period is being performed. As a result, normal driving starts while the touch detection operation is being performed, and the touch detection operation that started during the first period may affect the normal driving in the second period.

[0006] To prevent this, there is a method of not executing the touch detection operation during the first period. However, in this case, the cycle of the touch detection operation becomes longer depending on the length of the first period. As a result, the cycle in which the touch is detected becomes longer.

[0007] Therefore, the present disclosure has been made to solve the above-mentioned problems, and aims to provide a display device with a touch panel that is capable of preventing the cycle for touch detection from becoming longer even when operating at a variable frame rate, while preventing touch detection processing started within the first period out of the first and second periods that make up one frame period from affecting processing executed within the second period, and a control method thereof. [Means for solving the problem]

[0008] In order to solve the above problem, a display device with a touch panel according to a first aspect of the present disclosure is a display device with a touch panel that operates at a variable frame rate, and the variable frame rate is realized by changing a length of a first period out of a first period and a second period that constitute one frame period. The display device with a touch panel includes a touch panel including pixel electrodes, and a control unit that executes a write process of writing data signals to the pixel electrodes and a touch detection process by the touch panel, and the control unit starts a first touch detection process within the first period, terminates the first touch detection process before the second period starts after starting the first touch detection process, does not output first report data reporting a detection result by the first touch detection process if the length of the first period is less than a predetermined length, outputs the first report data if the length of the first period is equal to or greater than the predetermined length, and executes a second touch detection process, the write process, and a process of outputting second report data reporting a detection result by the second touch detection process after the second period starts.

[0009] A control method for a display device with a touch panel according to a second aspect is a control method for a display device with a touch panel including a pixel electrode and operating at a variable frame rate, the variable frame rate being realized by changing a length of a first period out of a first period and a second period constituting one frame period, and the control method includes the steps of starting a first touch detection process by the touch panel within the first period, terminating the first touch detection process before the second period starts after the start of the first touch detection process, not outputting first report data reporting a detection result by the first touch detection process if the length of the first period is less than a predetermined length, and outputting the first report data if the length of the first period is equal to or greater than the predetermined length, and executing a second touch detection process by the touch panel after the second period starts, a write process of writing a data signal to the pixel electrode, and a process of outputting second report data reporting the detection result by the second touch detection process. Effect of the Invention

[0010] According to the above configuration, even when operating at a variable frame rate in which the length of the first period changes, the first touch detection process is forcibly ended before the second period starts after the first touch detection process starts. This makes it possible to prevent the first touch detection process started within the first period from affecting the process executed within the second period. Furthermore, when the length of the first period is equal to or longer than a predetermined length required for the touch detection process, the process of outputting the first report data is performed, making it possible to prevent the cycle in which touches are detected from becoming longer than when the touch detection process is not executed in the first period. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a configuration of a display system 100a according to an embodiment. [Diagram 2] FIG. 2 is a plan view that illustrates a schematic configuration of touch panel 1. As shown in FIG. [Diagram 3] FIG. 3 is a circuit diagram for explaining the connection relationship between the thin film transistor 13 and the pixel electrode 14. As shown in FIG. [Figure 4] FIG. 4 is a diagram (1) for explaining the operation of the display device 100 with a variable frame rate. [Diagram 5] FIG. 5 is a diagram (2) for explaining the operation of the display device 100 at a variable frame rate. [Figure 6] FIG. 6 is a diagram (3) for explaining the operation of the display device 100 at a variable frame rate. [Figure 7] FIG. 7 is a block diagram showing a configuration of a display system 200a according to a modified example of the embodiment. [Figure 8] FIG. 8 is a diagram (1) for explaining the operation at a variable frame rate of the display device 200 according to a modified example of the embodiment. [Figure 9]FIG. 9 is a diagram (2) for explaining the operation at a variable frame rate of the display device 200 according to the modified example of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated. In order to make the description easier to understand, the drawings referred to below show simplified or schematic configurations, and some components are omitted. In addition, the dimensional ratios between the components shown in each drawing do not necessarily represent the actual dimensional ratios.

[0013] [Overall configuration of the display system] The configuration of a touch panel-equipped display device 100 (hereinafter referred to as "display device 100") according to this embodiment and the configuration of a display system 100a according to this embodiment will be described below. Fig. 1 is a block diagram showing the configuration of the display system 100a according to this embodiment.

[0014] As shown in Fig. 1, the display system 100a includes a display device 100 and a host controller 3. In Fig. 1, the display device 100 and the host controller 3 are illustrated as separate devices. However, a configuration functioning as the display device 100 and a configuration functioning as the host controller 3 may be integrally housed in one device.

[0015] The display device 100 includes a touch panel 1 and a control circuit 2. The display device 100 displays a video or image on the touch panel 1. The display device 100 also detects a touch by a pointer through the touch panel 1. The pointer includes a finger and a pen. The control circuit 2 includes a processor that performs control processing related to touch detection on the touch panel 1 and control processing related to display.

[0016] FIG. 2 is a plan view showing a schematic configuration of the touch panel 1. As shown in FIG. 2, the touch panel 1 includes a touch detection electrode 11, a drive circuit 12, a thin film transistor 13, and a pixel electrode 14. In the present embodiment, the control circuit 2 is disposed on the touch panel 1. Note that, without being limited to this example, the control circuit 2 may be disposed outside the touch panel 1, and the control circuit 2 and the touch panel 1 may be connected by wiring (for example, a flexible printed circuit board). The touch panel 1 is, for example, an in-cell type touch panel. That is, the touch detection electrode 11 serves both as an electrode for detecting a touch and as a counter electrode for generating an electric field between the electrode and a pixel electrode for displaying an image. Note that, in FIG. 1, for ease of explanation, one touch detection electrode 11 and one pixel electrode 14 are shown. The drive circuit 12 includes, for example, one or more integrated circuits.

[0017] As shown in FIG. 2, the touch detection electrodes 11 are arranged, for example, in a matrix. The drive circuit 12 includes a touch detection driver. The touch detection electrodes 11 and the drive circuit 12 (touch detection driver) are connected to each other via touch signal lines 15. The touch detection electrodes 11 change their capacitance by capacitive coupling with a pointer. The drive circuit 12 supplies touch drive signals (pulse signals) to the touch detection electrodes 11. The waveform of the pulse signal changes depending on the magnitude of the capacitance of the touch detection electrodes 11. The drive circuit 12 detects a touch by a pointer (touched position) based on the waveform of a pulse signal (hereinafter, referred to as a "detection signal") from the touch detection electrodes 11. Note that the "touch" is a concept that includes not only the contact of a pointer with the touch panel 1, but also the approach of a pointer to the touch panel 1. That is, the touch panel 1 is a self-capacitance type touch panel. Note that the present invention is not limited to this example, and the touch panel 1 may be configured as a mutual capacitance type touch panel. The process of detecting a touch by a pointer on the touch panel 1 is hereinafter referred to as a "touch detection process."

[0018] 3 is a circuit diagram for explaining the connection relationship between the thin film transistor 13 and the pixel electrode 14. The drive circuit 12 (see FIG. 1) further includes a gate driver and a source driver. The gate driver of the drive circuit 12 is connected to a gate line 16. The source driver of the drive circuit 12 is connected to a source line 17. A gate electrode of the thin film transistor 13 is connected to the gate line 16, and a source electrode of the thin film transistor 13 is connected to the source line 17. A drain electrode of the thin film transistor 13 is connected to the pixel electrode 14. The pixel electrode 14 forms a capacitance with the touch detection electrode 11. The touch detection electrode 11 is provided in common to the multiple pixel electrodes 14 and functions as a common electrode.

[0019] The gate driver of the drive circuit 12 sequentially supplies a gate signal (scanning signal) to each of the multiple gate lines 16. The source driver of the drive circuit 12 supplies a data signal based on a video signal to each of the multiple source lines 17. As a result, the thin film transistor 13 to which the gate signal is supplied is turned on, and the data signal is written to the pixel electrode 14. The process of writing the data signal to the pixel electrode 14 is hereinafter referred to as a "write process." In the touch panel 1, an electric field generated by the pixel electrode 14 and the touch detection electrode 11 (common electrode) drives a liquid crystal layer (not shown) to display an image.

[0020] 4 to 6 are diagrams for explaining the operation of the display device 100 at a variable frame rate. Here, the display device 100 is a display device that operates at a variable frame rate as shown in FIG. 4 to FIG. 6. The "variable frame rate" is realized by changing the length of the first period out of the first period and the second period that constitute one frame period. In this embodiment, the first period is hereinafter referred to as the "extension period". The second period is hereinafter referred to as the "normal drive period". The "one frame period" is the time interval during which the vertical synchronization signal is input to the drive circuit 12. The normal drive period is a period having a constant length (a period whose length does not change). The extension period is a period for extending the length of one frame period with respect to the normal drive period. The length of the extension period may change regularly or randomly. The length of the extension period may change periodically for each frame or for each multiple frames, or may change randomly. The purpose of using the variable frame rate is not particularly limited. For example, the frame rate may be changed according to the amount of change (movement) of the image in the moving image in order to reduce power consumption. In this case, the display device 100 operates at a high frame rate (for example, 120 Hz) in scenes with many changes in the image, and operates at a low frame rate (for example, 60 Hz) in scenes with few changes in the image.

[0021] As shown in Fig. 4, the control circuit 2 inputs a signal ST to the drive circuit 12 to execute a touch detection process. The drive circuit 12 executes the touch detection process when the signal ST is at a low level, and stops the touch detection process when the signal ST is at a high level. The control circuit 2 also transmits report data RP including the touch position (touch coordinates) detected by the drive circuit 12 to the host controller 3. The host controller 3 receives (reads) the report data RP when a strobe signal SR output from the control circuit 2 becomes a low level, as shown in Fig. 4.

[0022] As shown in FIG. 4, the normal drive period includes a touch detection period T in which a touch detection process is performed, a display period D in which a write process is performed, and a vertical blanking period V (vertical blanking period). In this embodiment, the normal drive period is executed in the order of vertical blanking (vertical blanking period V), touch detection process (touch detection period T), and write process (display period D). That is, in the normal drive period, the control circuit 2 changes the signal ST from a High level to a Low level after the vertical blanking period V ends, and then changes the signal ST to a High level. The length of the vertical blanking period V is a length that does not change and is T0. In this embodiment, the display device 100 is driven by an LVB (Long Vertical Blanking) method in which only one vertical blanking period V is provided in the normal drive period.

[0023] The extension period is a period during which writing processing is not performed and updating of the display of the touch panel 1 is paused. If no extension period is provided within one frame period (if the length of the extension period is 0), the frame rate is set to the upper limit. In this case, as shown in FIG. 4, the length of one frame period is equal to the normal drive period TN.

[0024] As shown in FIG. 4, one frame period TLa includes an extension period TLa1 and a normal drive period TLa2. In this embodiment, the normal drive period TLa2 is provided after the extension period TLa1 in the one frame period TLa. The extension period TLa1 includes a vertical blanking period V and a touch detection period T. That is, in this embodiment, the touch detection process is performed during the extension period TLa1. Here, when improving the touch detection rate, it is possible to configure the control circuit (IC) so that an additional touch detection process is performed during the normal drive period. However, when performing the additional touch detection process during the normal drive period, it is necessary to prepare a grace period in advance to enable the additional touch detection process to be performed during the normal drive period even when driving is performed in which the additional touch detection process does not need to be added. In an in-cell type touch panel, since the touch detection process and the writing process are performed in a time-division manner, a control circuit (IC) having even higher performance is required to provide the above grace period. For this reason, driving in which it is not necessary to add the additional touch detection process (normal driving) is performed by a control circuit (IC) having excessive performance. In contrast, in this embodiment, since the touch detection process is added within the extended period, it is not necessary to change the driving during the normal driving period. As a result, in this embodiment, it is possible to prevent the required performance of the control circuit (IC) from becoming excessive.

[0025] Here, as shown in FIG. 4, when the length of the extension period is equal to or longer than a predetermined length required for the touch detection process, the control circuit 2 outputs report data RP reporting the detection result of the touch detection process to the host controller 3. In the example shown in FIG. 4, the "predetermined length required for the touch detection process" is the sum of the length T0 of the period (vertical blanking period V) from time t1 when the extension period TLa1 starts to time t2 when the touch detection process starts, and the length TT of the period T during which the touch detection process is being executed. The length TT is the time required to acquire (scan) all the detection signals of the multiple touch detection electrodes 11. That is, when the length of the extension period is equal to or longer than the sum of the period T0 and the period TT, the report data RP is output to the host controller 3. The report data RP is output to the host controller 3 at time t4, which is later than time t3 when the touch detection process ends.

[0026] As a result, the cycle in which the report data RP is output (the cycle in which a touch is detected) can be shortened to the period TR1 from time t6 to time t7, compared to when the touch detection process is not executed in the extended period (when the period is from time t0 to time t7). That is, according to the above configuration, the touch detection rate can be increased. Then, at time t5 after time t3, the extended period TLa1 is switched to the normal drive period TLa2. Note that, although time t4 is described as being prior to time t5 in FIG. 4, time t4 may be later than time t5.

[0027] Also, in the display device 100, the maximum value of the touch detection cycle (the minimum value of the touch detection rate) is TRr. That is, the required touch detection cycle is equal to or less than TRr. In this case, the maximum value of the length of the extension period is TRr. For example, the normal drive period TN is 8.33 ms (120 Hz), and the maximum value TRr is 9.09 ms (the lower limit of the touch detection rate is 110 Hz). In this case, in the example shown in FIG. 4, the extension period TLa1 is 0.76 ms, so the period TR1 (the period from the time t6 of touch detection in the extension period to the time t7 of touch detection in the normal drive period) is 0.76 ms. Therefore, the period TR1 is smaller than the maximum value of the touch detection cycle (9.09 ms).

[0028] Furthermore, when the lower limit x of the frame rate (frame repetition frequency) is f, which is the frame rate when one frame period includes only the normal driving period TN, and the required touch detection rate is m, the display device 100 operates for a video signal in which the lower limit x satisfies the following formula (1): f×m / (f+m) < x ··· (1) Here, if m = 110 and f = 120 as in the example above, then x > 57.39.

[0029] 6 is a diagram showing the operation during one frame period TLc when the frame rate is low (for example, 58 Hz). The period TRx from the time when the report data RP is output in the extension period TLc1 to the time when the report data RP is output in the normal driving period TLc2 is 8.91 ms. Therefore, the touch detection rate is 116 Hz, which is greater than m.

[0030] Moreover, when the length of the extension period is less than a predetermined length required for the touch detection process, the control circuit 2 discards the detection result of the touch detection process. For example, as shown in FIG. 5, when switching from the extension period TLb1 to the normal drive period TLb2, the control circuit 2 forcibly ends the touch detection process. Specifically, when the length TTa (the length of the period from the end time t11 of the vertical blanking period V to the start time t12 of the normal drive period TLb2) obtained by subtracting the length T0 of the vertical blanking period V from the extension period TLb1 constituting one frame period TLb is less than TT, the control circuit 2 changes the signal ST from a low level to a high level and forcibly ends the touch detection process. When the length TTa is less than TT, the control circuit 2 deletes the detection result of the touch detection process in the extension period TLb1 from a memory (not shown). Then, the control circuit 2 holds the signal SR at a high level until the touch detection process in the normal drive period TLb2 is completed. If the touch detection process cannot be completed within the extension period, unnecessary detection results can be discarded and incomplete report data RP can be prevented from being transmitted to the host controller 3.

[0031] Also, even if the touch detection process is not performed within the extension period TLb1, the length of the extension period TLb1 is short, so that the decrease in the touch detection rate is suppressed. For example, as shown in FIG. 5, when the report data RP of the extension period TLb1 is not output to the host controller 3, the cycle TR2 of the touch detection is a period from time t13 when the report data RP of the normal drive period TN immediately before the extension period TLb1 is output to time t14 when the report data RP of the normal drive period TLb2 immediately after the extension period TLb1 is output. Here, if the extension period TLb1 is 0.68 ms, and the normal drive periods TN and TLb2 are each 8.33 ms, the cycle TR2 of the touch detection is 9.01 ms (=0.68 ms+8.33 ms). In this case, the touch detection rate is 111 Hz, which is a value higher than the lower limit value 110 Hz of the touch detection rate described above, and the decrease in the touch detection rate is maintained at a value higher than the lower limit value.

[0032] (Display device control method) Next, a control method for the display device 100 according to the present embodiment will be described with reference to FIGS.

[0033] <When the extension period is longer than the specified period> A control method of the display device 100 when the length of the extension period TLa1 is equal to or longer than a predetermined length (T0+TT) required for the touch detection process will be described with reference to Fig. 4. As shown in Fig. 4, at time t1, the control circuit 2 starts the extension period TLa1 of the frame period TLa. The control circuit 2 does not execute the touch detection process and the write process during the period from time t1 to time t2 (vertical blanking period V).

[0034] When the vertical blanking period V ends at time t2, the control circuit 2 changes the signal ST from High level to Low level. During the period from time t2 to time t3, the control circuit 2 keeps the signal ST at Low level and executes the touch detection process.

[0035] In the period from time t4 to time t6, the control circuit 2 outputs report data RP to the host controller 3. The host controller 3 acquires the report data RP.

[0036] At time t5, the control circuit 2 starts the normal drive period TLa2 of the frame period TLa. The control circuit 2 does not execute the touch detection process and the write process during the period from time t5 to time t7a (vertical blanking period V).

[0037] When the vertical blanking period V ends at time t7a, the control circuit 2 changes the signal ST from High level to Low level. During the period from time t7a to time t7b, the control circuit 2 keeps the signal ST at Low level and executes the touch detection process.

[0038] In the period from time t7b to time t8 (display period D), the control circuit 2 executes a write process. In addition, in the period from time t7c to time t7, the control circuit 2 outputs report data RP to the host controller 3. The host controller 3 acquires the report data RP. Then, at time t8, the next frame period starts.

[0039] According to the above control method, the touch detection process is performed within the extension period TLa1, so that it is possible to prevent the cycle of detecting a touch from becoming long.

[0040] <When the extension period is less than the specified period> A control method of the display device 100 when the length of the extension period TLa1 is less than a predetermined length (T0+TT) required for the touch detection process will be described with reference to Fig. 5. As shown in Fig. 5, at time t10, the control circuit 2 starts the extension period TLb1 of the frame period TLb. The control circuit 2 does not execute the touch detection process and the write process during the period from time t10 to time t11 (vertical blanking period V).

[0041] At time t11, when the vertical blanking period V ends, the control circuit 2 changes the signal ST from a High level to a Low level. The control circuit 2 executes the touch detection process. Here, at time t12, when the extension period TLb1 ends and the normal drive period TLb2 starts, the control circuit 2 changes the signal ST from a Low level to a High level even if the length of the period during which the touch detection process is being executed is less than TT. This forces the touch detection process to end (be stopped). In this case, the control circuit 2 does not output report data RP related to the stopped touch detection process to the host controller 3.

[0042] At time t12, the control circuit 2 starts the normal drive period TLb2 of the frame period TLb. The control method thereafter is the same as that of the normal drive period TLa2 when the length of the extension period is equal to or longer than the predetermined length required for the touch detection process, and therefore will not be described.

[0043] According to the above control method, even if the extension period TLb1 is short, the touch detection process is forcibly terminated before the normal drive period TLb2 starts. This makes it possible to prevent the touch detection process started during the extension period TLb1 from affecting the process executed during the normal drive period TLb2.

[0044] [Transformation, etc.] As described above, the above-described embodiments are merely examples for implementing the present disclosure. Therefore, the present disclosure is not limited to the above-described embodiments, and can be implemented by appropriately modifying the above-described embodiments without departing from the spirit of the present disclosure.

[0045] (1) In the above embodiment, the touch detection process is executed once each in the extension period and the normal drive period, but the present disclosure is not limited to this. That is, the touch detection process may be executed multiple times each in the extension period and the normal drive period.

[0046] (2) In the above embodiment, examples of numerical values ​​(e.g., the length of the normal driving period is 8.33 ms) are shown and described, but the present disclosure is not limited to these. Values ​​other than the above numerical values ​​(e.g., the length of the normal driving period is 16.66 ms) may be applied to the display device of the present disclosure.

[0047] (3) In the above embodiment, an example has been shown in which the report data RP is output when the length of the extension period is equal to or longer than the combined length (T0+TT) of the vertical blanking period V and the length TT of the touch detection period T, but the present disclosure is not limited to this. For example, when the vertical blanking period V is provided after the touch detection period T in the extension period, the report data RP may be output when the length of the extension period is equal to or longer than TT, or the report data RP may be output only when the length of the extension period is longer than T0+TT.

[0048] (4) In the above embodiment, an example has been shown in which the detection result of the touch detection process is erased from the memory when the length of the extension period is less than the combined length (T0+TT) of the vertical blanking period V and the length TT of the touch detection period T, but the present disclosure is not limited to this. That is, when the length of the extension period is less than the combined length (T0+TT) of the vertical blanking period V and the length TT of the touch detection period T, the detection result does not need to be erased from the memory unless the report data RP is transmitted to the host controller 3.

[0049] (5) In the above embodiment, an example in which the second period (normal driving period) is provided after the first period (extension period) in one frame period has been described, but the present disclosure is not limited to this. For example, as in a display system 200a according to a modified example shown in Figures 7 to 9, the first period (extension period) may be provided after the second period (normal driving period) in one frame period.

[0050] As shown in FIG. 7, a display system 200a according to a modified example includes a display device 200 with a touch panel including a control circuit 202. As shown in FIG. 8, the control circuit 202 causes the drive circuit 12 to perform an operation in an extension period TLb2 after an operation in a normal drive period TLd1 within one frame period TLd. The control circuit 202 performs a touch detection process T in the extension period TLb2. Then, when the length of the extension period TLd2 is equal to or longer than a predetermined length (for example, T0+TT), the control circuit 202 outputs report data RP to the host controller 3. Also, as shown in FIG. 9, when the length of the extension period TLe2 (T0+TTb in FIG. 9) is less than a predetermined length (for example, T0+TT), the control circuit 202 discards the report data RP without outputting it to the host controller 3. For example, in an extension period TLe2 following a normal drive period TLe1 in a frame period TLe, when the next frame period is about to start during a touch detection process, the control circuit 202 ends the touch detection process, does not output the report data RP, and starts driving for the normal drive period. In this manner, even in the modified example, the touch detection process is executed in the extension period, so that it is possible to prevent the cycle in which touches are detected from becoming longer and to prevent the touch detection process started in the extension period from affecting the process executed in the normal drive period.

[0051] The above-mentioned configuration can be explained as follows.

[0052] A display device with a touch panel according to a first configuration is a display device with a touch panel that operates at a variable frame rate, and the variable frame rate is realized by changing a length of a first period out of a first period and a second period that constitute one frame period. The display device with a touch panel includes a touch panel including pixel electrodes, and a control unit that executes a write process of writing data signals to the pixel electrodes and a touch detection process by the touch panel. The control unit starts a first touch detection process within the first period, ends the first touch detection process before the second period starts after starting the first touch detection process, does not output first report data reporting a detection result by the first touch detection process if the length of the first period is less than a predetermined length, outputs the first report data if the length of the first period is equal to or greater than the predetermined length, and executes a second touch detection process, the write process, and a process of outputting second report data reporting a detection result by the second touch detection process after the second period starts (first configuration).

[0053] According to the first configuration, even when operating at a variable frame rate in which the length of the first period changes, the first touch detection process is forcibly terminated before the second period starts. This makes it possible to prevent the first touch detection process started within the first period from affecting the process executed within the second period following the first touch detection process. Furthermore, when the length of the first period is equal to or longer than a predetermined length, the process of outputting the first report data is performed, so that it is possible to prevent the cycle in which touches are detected from becoming longer than when the touch detection process is not executed during the first period.

[0054] In the first configuration, the control unit terminates the first touch detection process when the length of the period during which the first touch detection process is performed within the first period becomes equal to or longer than the predetermined length (second configuration).

[0055] According to the second configuration, the first touch detection process can be ended when the first touch detection process is completed.

[0056] In the first and second configurations, the control unit executes a process of discarding a detection result of the first touch detection process when a length of the first period is less than the predetermined length (third configuration).

[0057] According to the third configuration, when the first touch detection process cannot be completed, unnecessary detection results can be discarded.

[0058] A control method for a display device with a touch panel according to a fourth configuration is a control method for a display device with a touch panel including a pixel electrode and operating at a variable frame rate, the variable frame rate being realized by changing a length of a first period out of a first period and a second period constituting one frame period, and the control method includes the steps of starting a first touch detection process by the touch panel within the first period, terminating the first touch detection process before the second period starts after the start of the first touch detection process, not outputting first report data reporting a detection result by the first touch detection process if the length of the first period is less than a predetermined length, outputting the first report data if the length of the first period is equal to or greater than the predetermined length, and executing a second touch detection process by the touch panel after the second period starts, a write process of writing a data signal to the pixel electrode, and a process of outputting second report data reporting the detection result by the second touch detection process (fourth configuration).

[0059] According to the above fourth configuration, it is possible to provide a control method for a display device with a touch panel that can prevent the cycle in which touches are detected from becoming longer even when operating at a variable frame rate, while preventing a touch detection process started within a first period out of a first period and a second period that constitute one frame period from affecting a process executed within a second period following the touch detection process. [Explanation of symbols]

[0060] 1...touch panel, 2, 202...control circuit, 3...host controller, 11...touch detection electrode, 12...drive circuit, 13...thin film transistor, 14...pixel electrode, 100, 200...display device with touch panel

Claims

1. A display device with a touch panel that operates at a variable frame rate, the variable frame rate is realized by changing a length of a first period out of a first period and a second period that constitute one frame period, The display device with a touch panel includes: a touch panel including pixel electrodes; a control unit that executes a write process for writing a data signal to the pixel electrodes and a touch detection process by the touch panel; The control unit is starting a first touch detection process within the first period; ending the first touch detection process before the second period starts after starting the first touch detection process; When a length of the first period is less than a predetermined length, first report data for reporting a detection result of the first touch detection process is not output, and when a length of the first period is equal to or greater than the predetermined length, the first report data is output; a display device with a touch panel that executes, after the second period starts, a second touch detection process, the writing process, and a process of outputting second report data that reports a detection result by the second touch detection process.

2. 2 . The display device with a touch panel according to claim 1 , wherein the control unit terminates the first touch detection process when a length of a period during which the first touch detection process is performed within the first period becomes equal to or longer than the predetermined length.

3. The display device with a touch panel according to claim 1 , wherein the control unit executes a process of discarding a detection result of the first touch detection process when a length of the first period is less than the predetermined length.

4. A method for controlling a display device with a touch panel including a pixel electrode and operating at a variable frame rate, comprising: the variable frame rate is realized by changing a length of a first period out of a first period and a second period that constitute one frame period, starting a first touch detection process by the touch panel during the first period; ending the first touch detection process before the second period starts after starting the first touch detection process; When a length of the first period is less than a predetermined length, first report data for reporting a detection result of the first touch detection process is not output, and when a length of the first period is equal to or greater than the predetermined length, the first report data is output; A control method for a display device with a touch panel, which executes, after the second period starts, a second touch detection process by the touch panel, a writing process for writing a data signal to the pixel electrode, and a process for outputting second report data that reports a detection result by the second touch detection process.

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