Display device

Abstract

To improve display grade.SOLUTION: A display device 10 includes: a display panel 11; an image display unit 32; an image processing unit 34 which can process original data on an image to output processed data to the image display unit 32; a first detection unit 36 which detects pressing force; a second detection unit 37 which detects a pressing position where the pressing force acts on; and a control unit 35 which controls the image processing unit 34. The first detection unit 36 and the second detection unit 37 respectively detect the pressing force and the pressing position every unit time. The control unit 35 extracts a first variation by subtracting the pressing force detected by the first detection unit 36 at a first time point from the pressing force detected by the first detection unit 36 at a second time point when the unit time lapses from the first time point and, if an absolute value of the first variation is equal to or higher than a first threshold TH1, causes the image processing unit 34 to process the original data in a first region A1 having the pressing position detected by the second detection unit 37 at the second time point centered thereon so as to output first data as the processed data in a display gradation lower than that for the original data.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a display device. [Background technology]

[0002] Conventionally, a liquid crystal display device described in Patent Document 1 is known as an example of a display device. The liquid crystal display device described in Patent Document 1 has an image display section, an XY coordinate detection section, an image processing section, and a timing control section. The image display section has a liquid crystal display panel, a gate driver, a source driver, a touch panel, and a backlight (not shown). When the touch panel detects that a user is touching the liquid crystal display panel, the XY coordinate detection section identifies the location pressed by the user. The image processing section displays a lower gradation at the location pressed by the user than the display image at that location, and displays the original display image (i.e., the original gradation) when the user stops pressing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2012 / 043489 Summary of the Invention [Problem to be solved by the invention]

[0004] In the liquid crystal display device described in the above-mentioned Patent Document 1, the strength of a user's pressure on the touch panel is detected, and if the pressure detection unit determines that the pressure is strong, the image processing unit is controlled to mask the pressed area. In Patent Document 1, the strength of pressure is detected based on the amount of change in pressure from a state where no pressure is applied. For this reason, there is a problem in that it is difficult to avoid display defects that occur at the pressed area the moment the pressure changes, and it is difficult to sufficiently improve the display quality.

[0005] The technology described in this specification was developed based on the above circumstances, and aims to improve display quality. [Means for solving the problem]

[0006] (1) A display device according to the technology described in this specification includes a display panel having a display surface, an image display unit that displays an image on the display surface, an image processing unit that processes original data related to the image and outputs the processed data to the image display unit, a first detection unit that detects a pressure acting on the display surface, a second detection unit that detects a pressure position on the display surface where the pressure acts, and a control unit that controls the image processing unit, wherein the first detection unit and the second detection unit detect the pressure and the pressure position every unit time, and the control unit calculates the pressure detected by the first detection unit at a first point in time as a function of the pressure. a first change amount, which is a change amount related to the pressure, is extracted by subtracting it from the pressure detected by the first detection unit at a second time point when the unit time has elapsed from the first time point, and if the absolute value of the extracted first change amount is equal to or greater than a first threshold value, the image processing unit is caused to process the original data in at least a first region centered on the pressure position detected by the second detection unit at the second time point and output first data having a lower display gradation than the original data as the processed data, and if the absolute value of the first change amount is less than a first threshold value, the image processing unit is caused to output the original data.

[0007] (2) In addition to (1) above, in the display device, when the first amount of change does not exceed a second threshold value that is greater than the first threshold value and is equal to or greater than the first threshold value, the control unit may cause the image processing unit to process the original data in the first region and output the first data as the processed data, and when the first amount of change is equal to or greater than the second threshold value, the control unit may cause the image processing unit to process the original data in a second region that is centered on the pressure position detected by the second detection unit at least at the second time point and is wider than the first region, and output second data having a lower display gradation than the first data as the processed data.

[0008] (3) In addition to (1) or (2) above, the display device may further include a stylus pen that applies the pressure to the display surface, and a third detection unit that detects a tilt angle of the stylus pen with respect to the display surface, wherein the stylus pen has the first detection unit, and the control unit may multiply the pressure detected by the first detection unit by "sinθ" when the tilt angle detected by the third detection unit is "θ" to calculate a corrected pressure, and extract the first change amount based on the corrected pressure.

[0009] (4) A display device according to the technology described in this specification includes a display panel having a display surface, an image display unit that displays an image on the display surface, an image processing unit that processes original data related to the image and outputs the processed data to the image display unit, a first detection unit that detects a pressure acting on the display surface, a second detection unit that detects a pressure position on the display surface where the pressure acts, and a control unit that controls the image processing unit, wherein the first detection unit and the second detection unit detect the pressure and the pressure position every unit time, and the control unit detects a first pressure position that is the pressure position detected by the second detection unit at a first time point and a second pressure position that is the pressure position detected by the second detection unit at a second time point when the unit time has elapsed from the first time point. and extracting a second change amount, which is the amount of change related to the pressure position, based on the second pressure position, which is the pressure position outputted from the first detection unit, and if the absolute value of the extracted second change amount is equal to or greater than a third threshold value and the pressure detected by the first detection unit at the second time point is equal to or greater than a fourth threshold value, causing the image processing unit to process the original data in a third region, which is a range spanning at least the first pressure position and the second pressure position, and output third data having a lower display gradation than the original data as the processed data, and if the second change amount is less than the third threshold value or if the pressure detected by the first detection unit at the second time point is less than the fourth threshold value, causing the image processing unit to output the original data.

[0010] (5) In addition to (4) above, in the display device, when the second amount of change does not exceed a fifth threshold that is greater than the third threshold and is equal to or greater than the third threshold, the control unit may cause the image processing unit to process the original data in the third region and output the third data as the processed data, and when the second amount of change is equal to or greater than the fifth threshold, the control unit may cause the image processing unit to process the original data in a fourth region that is at least in a range spanning the first pressing position and the second pressing position and is wider than the third region, and output fourth data having a lower display gradation than the third data as the processed data.

[0011] (6) In addition to (5) above, the control unit of the display device may also cause the image processing unit to process the original data in a fifth region that includes the third region and whose range gradually increases as the fifth region approaches the second pressing position from the first pressing position, and output the third data or the fourth data. Effect of the Invention

[0012] According to the technology described in this specification, it is possible to improve the display quality. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a plan view of a liquid crystal panel, drivers, a flexible substrate, and the like that constitute a liquid crystal display device according to a first embodiment; [Diagram 2] 1 is a cross-sectional view of a liquid crystal panel, each driver, a flexible board, and the like according to the first embodiment; [Diagram 3] FIG. 1 is a circuit diagram showing an electrical configuration of an array substrate that constitutes a liquid crystal panel according to a first embodiment. [Figure 4] 1 is a cross-sectional view of a liquid crystal panel showing a state in which a stylus pen according to a first embodiment is in contact with the liquid crystal panel; [Diagram 5] FIG. 2 is a cross-sectional view of the liquid crystal panel showing a state in which the liquid crystal panel is pressed by a stylus pen according to the first embodiment; [Figure 6]6 is a cross-sectional view of the liquid crystal panel showing a state in which the liquid crystal panel is pressed by the stylus pen according to the first embodiment with a stronger pressing force than that in FIG. 5; [Figure 7] FIG. 1 is a block diagram showing an electrical configuration of a liquid crystal display device according to a first embodiment. [Figure 8] 1 is a flowchart of a process performed in association with touch detection according to the first embodiment; [Figure 9] FIG. 11 is a block diagram showing an electrical configuration of a liquid crystal display device according to a second embodiment. [Figure 10] 11 is a cross-sectional view of a liquid crystal panel showing the inclination angle of a stylus pen with respect to a display surface of the liquid crystal panel according to the second embodiment; [Figure 11] FIG. 11 is a block diagram showing an electrical configuration of a liquid crystal display device according to a third embodiment. [Figure 12] 11 is a cross-sectional view of a liquid crystal panel showing a state in which the liquid crystal panel is pressed by a stylus pen according to a third embodiment; [Figure 13] FIG. 11 is a cross-sectional view of a liquid crystal panel showing a state in which a stylus pen according to a third embodiment has moved from a first pressing position to a second pressing position; [Figure 14] 14 is a cross-sectional view of the liquid crystal panel showing a state in which the stylus pen according to the third embodiment has been moved from a first pressing position to a second pressing position farther than that shown in FIG. 13; [Figure 15] 11 is a flowchart of a process performed in association with touch detection according to the third embodiment. [Figure 16] FIG. 11 is a plan view of a liquid crystal panel showing a state in which a stylus pen according to a fourth embodiment has been moved from a first pressing position to a second pressing position; [Figure 17] FIG. 13 is a block diagram showing an electrical configuration of a liquid crystal display device according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <Embodiment 1> A first embodiment will be described with reference to Fig. 1 to Fig. 8. In this embodiment, a liquid crystal display device (display device) 10 having a display function and a touch panel function (position input function) is illustrated. Note that the X-axis, Y-axis, and Z-axis are shown in a part of each drawing, and each axis direction is drawn to be the direction shown in each drawing. Also, the upper side of Fig. 2, Fig. 5 to Fig. 7 is the front side, and the lower side of the drawings is the back side.

[0015] 1, a liquid crystal display device 10 includes at least a horizontally elongated rectangular liquid crystal panel (display panel) 11 capable of displaying an image, and a backlight device (illumination device) which is an external light source that irradiates the liquid crystal panel 11 with light to be used for display. The backlight device is disposed on the rear side (back side) of the liquid crystal panel 11, and includes a light source (e.g., an LED) that emits white light, and an optical member that converts the light from the light source into planar light by applying an optical effect. The central portion of the screen of the liquid crystal panel 11 is a display area AA where an image is displayed. In contrast, a frame-shaped outer peripheral portion surrounding the display area AA on the screen of the liquid crystal panel 11 is a non-display area NAA where no image is displayed.

[0016] The liquid crystal panel 11 will be described in detail with reference to FIG. 1 and FIG. 2. As shown in FIG. 1 and FIG. 2, the liquid crystal panel 11 is formed by bonding a pair of substrates 20 and 21. The front side (front side) of the pair of substrates 20 and 21 is an opposing substrate (CF substrate) 20, and the back side (rear side) is an array substrate (substrate) 21. The opposing substrate 20 and the array substrate 21 are both formed by laminating various films on the inner side of a glass substrate. Of the pair of main surfaces of the opposing substrate 20, the main surface on the front side (outer side) constitutes a display surface 11A capable of displaying an image in the liquid crystal panel 11. A liquid crystal layer (medium layer) 22 containing liquid crystal molecules, which are a substance whose optical properties change with the application of an electric field, is disposed between the pair of substrates 20 and 21. A seal portion 23 for sealing the liquid crystal layer 22 is disposed between the outer peripheral ends of the pair of substrates 20 and 21. The seal portion 23 is formed in a rectangular frame shape (endless ring shape) so as to surround the liquid crystal layer 22. A polarizing plate 15 is attached to the outer surface side of each of the substrates 20 and 21.

[0017] As shown in Fig. 1 and Fig. 2, the short side dimension and the long side dimension of the counter substrate 20 are shorter than those of the array substrate 21. The counter substrate 20 is attached to the array substrate 21 in such a manner that one end in the short side direction (Y-axis direction) and one end in the long side direction (X-axis direction) are aligned. Therefore, the other end in the short side direction and the other end in the long side direction of the array substrate 21 are exposed portions 21A protruding laterally from the counter substrate 20. The exposed portion 21A has a substantially L-shaped planar shape and is entirely a non-display area NAA, and is provided with a source driver (first signal supply unit) 12, a gate driver (second signal supply unit) 13, and a flexible substrate 14 for supplying various signals related to the display function and touch panel function described below.

[0018] The source driver 12 and the gate driver 13 shown in FIG. 1 and FIG. 2 are each composed of an LSI chip having a driving circuit therein. The source driver 12 and the gate driver 13 are mounted on the exposed portion 21A of the array substrate 21 by COG (Chip On Glass). The source driver 12 is disposed at the other end of the array substrate 21 in the short side direction. The gate driver 13 is disposed at the other end of the array substrate 21 in the long side direction. The source driver 12 and the gate driver 13 process various signals transmitted by the flexible substrate 14. The source driver 12 supplies various signals (e.g., image signals and touch signals, etc.) to the wiring in the display area AA (specifically, the source wiring 27 and the touch wiring 30, which will be described later). The gate driver 13 supplies various signals (e.g., scanning signals, etc.) to the wiring in the display area AA (specifically, the gate wiring 26, which will be described later). The flexible substrate 14 is configured by forming a large number of wiring patterns on a base material made of a synthetic resin material (e.g., polyimide resin, etc.) having insulating properties and flexibility. 1 and 2, one end of the flexible substrate 14 is connected to the exposed portion 21A of the array substrate 21, and the other end is connected to an external circuit substrate. The flexible substrate 14 is connected to the other end of the array substrate 21 in the short side direction at a position where the source driver 12 is sandwiched between the flexible substrate 14 and the display area AA.

[0019] The liquid crystal panel 11 according to this embodiment has both a display function for displaying an image and a touch panel function for detecting a position (input position) input by a user based on the displayed image. A touch panel pattern for exerting the touch panel function is integrated (in-cell) in the liquid crystal panel 11. This touch panel pattern is a so-called projected capacitive type, and its detection method is a self-capacitive type. As shown in FIG. 1, the touch panel pattern is composed of a plurality of touch electrodes (position detection electrodes) 29 arranged in a matrix shape in the display surface 11A of the liquid crystal panel 11. The touch electrodes 29 are arranged in the display area AA of the liquid crystal panel 11. Therefore, the display area AA of the liquid crystal panel 11 is approximately coincident with a touch area (position input area) where an input position can be detected, and the non-display area NAA is approximately coincident with a non-touch area (non-position input area) where an input position cannot be detected. When a user approaches a conductive finger or a stylus pen 31 (position input object) described later to the display surface 11A of the liquid crystal panel 11 to input a position based on an image in the display area AA of the liquid crystal panel 11 that the user is viewing, a capacitance is formed between the finger or the stylus pen 31 and the touch electrode 29. As a result, the capacitance detected by the touch electrode 29 near the finger or the stylus pen 31 changes as the finger approaches, and becomes different from that of the touch electrode 29 far from the finger or the stylus pen 31, so that it is possible to detect the input position on the display surface 11A based on the change. When a pressing force is applied to the display surface 11A during position input using the finger or the stylus pen 31, the pressing position where the pressing force is applied is detected by the touch electrode 29. Note that the specific number of touch electrodes 29 installed can be changed as appropriate, other than that shown in FIG. 1. The touch electrode 29 is substantially rectangular in plan view, with each side measuring about several mm. Therefore, the size of the touch electrode 29 in a plan view is much larger than a pixel described later, and the touch electrode 29 is disposed in an area spanning a plurality of pixels in both the X-axis and Y-axis directions.

[0020] Next, the configuration of the display area AA in the array substrate 21 will be described with reference to FIG. 3. As shown in FIG. 3, at least TFTs (thin film transistors, switching elements) 24 and pixel electrodes 25 are provided on the inner surface side of the display area AA of the array substrate 21. The TFTs 24 and pixel electrodes 25 are arranged in a matrix shape (row and column shape) with a plurality of TFTs 24 and pixel electrodes 25 arranged at intervals along the X-axis direction and the Y-axis direction. Gate wiring (scanning wiring) 26 and source wiring (image wiring, signal wiring) 27 that are orthogonal (intersecting) to each other are provided around the TFTs 24 and pixel electrodes 25. The gate wiring 26 extends along the X-axis direction and a plurality of the gate wirings 26 are arranged at intervals along the Y-axis direction. A scanning signal is supplied to each of the gate wirings 26 from the gate driver 13 (see FIG. 1). The source wirings 27 extend along the Y-axis direction and a plurality of the source wirings 27 are arranged at intervals along the X-axis direction. An image signal (data signal) is supplied to each of the source wirings 27 from the source driver 12 (see FIG. 1). The TFT 24 has a gate electrode 24A connected to the gate line 26, a source electrode 24B connected to the source line 27, a drain electrode 24C connected to the pixel electrode 25, and a semiconductor portion 24D made of a semiconductor material and connected to the source electrode 24B and the drain electrode 24C. The TFT 24 is driven based on a scanning signal supplied to the gate electrode 24A by the gate line 26. Then, a potential related to an image signal supplied to the source electrode 24B by the source line 27 is supplied to the drain electrode 24C via the semiconductor portion 24D. As a result, the pixel electrode 25 is charged to a potential related to the image signal. The pixel electrode 25 is disposed in a region surrounded by the gate line 26 and the source line 27, and has a planar shape of, for example, a substantially rectangular shape.

[0021] As shown in FIG. 3, a common electrode 28 is formed on the inner surface of the display area AA of the array substrate 21 so as to overlap all the pixel electrodes 25. The common electrode 28 extends over almost the entire display area AA. The common electrode 28 is disposed on the side closer to the liquid crystal layer 22 in the Z-axis direction (the normal direction of the display surface 11A) with respect to the pixel electrodes 25, with an insulating film interposed therebetween. In the common electrode 28, a plurality of slits extending along the long side direction of each pixel electrode 25 are formed in the portion overlapping each pixel electrode 25. Note that the slits are not shown in FIG. 3. When a potential difference occurs between the pixel electrodes 25 and the common electrode 28 overlapping each other as the pixel electrodes 25 are charged, a fringe electric field (diagonal electric field) including a component along the main surface of the array substrate 21 as well as a component in the normal direction to the main surface of the array substrate 21 is generated between the opening edge of the slit and the pixel electrode 25. Therefore, the alignment state of the liquid crystal molecules contained in the liquid crystal layer 22 can be controlled by utilizing this fringe electric field. That is, the liquid crystal panel 11 according to this embodiment operates in a FFS (Fringe Field Switching) mode. The common electrode 28 constitutes the above-mentioned multiple touch electrodes 29. In addition to the above-mentioned slits, the common electrode 28 has partition slits that separate adjacent touch electrodes 29. The partition slits divide the common electrode 28 into a grid pattern and the common electrode 28 is composed of multiple touch electrodes 29 that are electrically independent from each other.

[0022] As shown in FIG. 3, a plurality of touch wirings (position detection wirings) 30 connected to a plurality of touch electrodes 29 are provided on the inner surface side of the display area AA of the array substrate 21. The touch wirings 30 extend along the Y-axis direction and are parallel to the source wirings 27. The plurality of touch wirings 30 are individually connected to the plurality of touch electrodes 29. A common signal (reference potential signal) related to the display function and a touch signal (position detection signal) related to the touch function are supplied to the touch wirings 30 from the source driver 12 at different timings (time division). The timing when the common signal is supplied from the source driver 12 to the touch wirings 30 is the display period, and the timing when the touch signal is supplied from the source driver 12 to the touch wirings 30 is the sensing period (position detection period). During the display period, the common signal is supplied to all the touch wirings 30, so that all the touch electrodes 29 become the reference potential and function as the common electrodes 28.

[0023] In addition, in the display area AA of the counter substrate 20, a plurality of color filters are provided at positions facing each pixel electrode 25 on the array substrate 21 side. The color filters are made of three colors, R (red), G (green), and B (blue), repeatedly arranged in a predetermined order, and together with the pixel electrodes 25, form pixels of each color (red pixels, green pixels, and blue pixels). The three pixels, red pixels, green pixels, and blue pixels, form a display pixel capable of displaying a color of a predetermined gradation. In addition, a light-shielding portion (black matrix) is formed between each color filter to prevent color mixing. Note that an alignment film for aligning liquid crystal molecules contained in the liquid crystal layer 22 is provided on the innermost surface of the counter substrate 20 and the array substrate 21, respectively.

[0024] The liquid crystal panel 11 according to the present embodiment has a display function for displaying an image, a touch panel function for detecting an input position by a user, and a pressing force detection function for detecting a force (pressing force) applied by a user to the display surface 11A of the liquid crystal panel 11 based on a displayed image. When the counter substrate 20 of the liquid crystal panel 11 is pressed by a user from the state shown in FIG. 4, a deflection occurs in the counter substrate 20 near the pressed portion as shown in FIG. 5. Then, the thickness of the liquid crystal layer 22 near the pressed portion becomes smaller than the thickness of the liquid crystal layer 22 in other portions. When the pressing force is larger than that in FIG. 5, the range in which the deflection occurs in the counter substrate 20 becomes wider than that in FIG. 5, and the thickness of the liquid crystal layer 22 tends to become smaller than that in FIG. 5, as shown in FIG. 6. Note that the polarizing plate 15 (see FIG. 2) is omitted in FIGS. 4 to 6. Also, although FIGS. 4 to 6 illustrate a case in which the display surface 11A is pressed by a stylus pen 31, the display surface 11A may be pressed by other position input objects including a finger. In this way, when the thickness of the liquid crystal layer 22 changes due to the application of a pressing force, the alignment state of the liquid crystal molecules is disturbed, and accordingly, a change occurs in the capacitance generated in the touch electrode 29. By utilizing this change in the capacitance generated in the touch electrode 29, it is possible to detect the pressing force acting on the counter substrate 20.

[0025] Next, the electrical configuration of the liquid crystal display device 10 will be described with reference to Fig. 7. As shown in Fig. 7, the liquid crystal display device 10 includes a timing controller (image display unit) 32 that supplies various signals related to images to the liquid crystal panel 11 to display images on the display surface 11A, a touch controller 33 that processes touch signals and the like from the touch electrodes 29, an image processing unit 34 that processes original data related to images supplied from an external host system HS, and a control unit 35 that controls the image processing unit 34.

[0026] The timing controller 32 outputs an image signal supplied from the image processing unit 34 to the source driver 12 and a scanning signal to the gate driver 13 at a predetermined timing. The touch controller 33 processes a touch signal and the like supplied from the touch electrode 29 through the touch wiring 30, and outputs the processed signal to the control unit 35. The touch controller 33 has a first detection unit 36 ​​that detects a pressing force acting on the display surface 11A from a finger or a stylus pen 31, and a second detection unit 37 that detects a pressing position on the display surface 11A where a pressing force is applied by the finger or the stylus pen 31. The image processing unit 34 is capable of processing original data relating to an image supplied from the host system HS and outputting the processed data to the timing controller 32. The image processing unit 34 is also capable of outputting the original data relating to an image supplied from the host system HS to the timing controller 32 without processing it. The control unit 35 can control whether or not the image processing unit 34 processes the above-mentioned original data. The control unit 35 has at least a memory for storing information and a timer capable of measuring time.

[0027] Conventionally, the strength of a user's pressure on a touch panel is detected, and when the pressure detection unit determines that the pressure is strong, the image processing unit is controlled to mask the pressed area. Conventionally, the strength of pressure is detected based on the amount of change in pressure from a state where no pressure is applied, so it was difficult to avoid display defects that occur at the pressed area the moment the pressure changes.

[0028] In this regard, in this embodiment, in order to realize a display that accurately reflects an instantaneous change in pressure, the following configuration is adopted. First, the touch controller 33 detects the pressure and the pressure position every unit time by the first detection unit 36 ​​and the second detection unit 37. Specifically, this "unit time" is set to about 8 ms, for example. Then, the control unit 35 extracts a first change amount, which is a change amount related to the pressure, by subtracting the first pressure, which is the pressure detected by the first detection unit 36 ​​at a certain timing (hereinafter referred to as a first time point), from the second pressure, which is the pressure detected by the first detection unit 36 ​​at a second time point when the unit time has elapsed from the first time point. When the first pressure is "F1" and the second pressure is "F2", the first change amount can be expressed as "F2-F1", and the absolute value of the first change amount can be expressed as "|F2-F1|".

[0029] Then, the control unit 35 judges whether the absolute value of the extracted first change amount is equal to or greater than a predetermined first threshold value TH1. Here, the first threshold value TH1, which is the judgment criterion, is a numerical value empirically found to be a value at which display defects occurring near the pressed location due to the pressing force can be visually recognized. In addition, if the extracted first change amount is a positive value, it is understood that the pressing force tends to increase over time, and if the extracted first change amount is a negative value, it is understood that the pressing force tends to decrease over time. If the judgment result is "YES", the control unit 35 causes the image processing unit 34 to process the original data in the first region A1 centered on the second pressing position P2, which is the pressing position detected by the second detection unit 37 at the second time point, and outputs the first data having a lower display gradation than the original data as processed data. As shown in FIG. 5, this first region A1 is a range in which bending of the opposing substrate 20 occurs near the pressed location and display defects can be visually recognized, and is, for example, a circular range in a plan view centered on the pressing position. The timing controller 32 performs display in the first area A1 with a display gradation based on the first data output from the image processor 34, so that display defects that may be visible at the moment when the pressure changes can be made less visible. Compared to the conventional case where the strength of pressure is detected based on the amount of change in pressure from a state where no pressure is applied, a display that accurately reflects the instantaneous change in pressure can be realized, and excellent display quality can be obtained. If the determination result is "NO", the control unit 35 does not cause the image processor 34 to process the original data, but causes the original data to be output to the timing controller 32.

[0030] In addition, the control unit 35 also performs a judgment based on a second threshold TH2, which is larger than the first threshold TH1, with respect to the first change amount. The second threshold TH2, which is the judgment criterion, is a value empirically found such that the change in display gradation occurring near the pressed location due to pressing is large and the range in which display defects are visually recognized is wide. Specifically, when the first change amount does not exceed the second threshold TH2 and is set to be equal to or greater than the first threshold TH1, the control unit 35 causes the image processing unit 34 to process the original data in the first region A1 and output the first data as processed data. On the other hand, when the first change amount is equal to or greater than the second threshold TH2, the control unit 35 causes the image processing unit 34 to process the original data in the second region A2, which is centered on the second pressing position P2 detected by the second detection unit 37 at the second time point and is wider than the first region A1, and output the second data, which has a display gradation lower than the first data, as processed data. 6, the second region A2 is a range in which a display defect may be visually recognized due to bending of the counter substrate 20 near the pressed point, and is, for example, a circular range in a plan view centered on the pressed position, and its diameter is larger than that of the first region A1. In this way, when the pressing force changes more significantly, a display with a lower display gradation is performed over a wider range, so that a display that more accurately reflects the instantaneous change in pressing force can be realized.

[0031] Next, a specific process performed in association with touch detection will be described with reference to the flowchart shown in FIG. 8. According to FIG. 8, when the liquid crystal display device 10 is powered on, the control unit 35 judges whether or not a touch has been detected (step S10). If the judgment result of step S10 is NO, the process returns to step S10, and the control unit 35 judges again whether or not a touch has been detected. If the judgment result of step S10 is YES, the control unit 35 causes the first detection unit 36 ​​and the second detection unit 37 provided in the touch controller 33 to detect the pressing force and the pressing position, respectively (step S11). Then, the control unit 35 judges whether or not a unit time has elapsed (step S12). If the judgment result of step S12 is NO, the process returns to step S12, and the control unit 35 judges whether or not a unit time has elapsed. If the judgment result of step S12 is YES, the control unit 35 causes the first detection unit 36 ​​and the second detection unit 37 to detect the pressing force and the pressing position, respectively, again (step S13). The timing when step S11 is performed is a "first time point", and the timing when step S13 is performed is a "second time point" when a unit time has elapsed since the "first time point".

[0032] The control unit 35 subtracts the first pressure F1, which is the pressure detected by the first detection unit 36 ​​in step S11, from the second pressure F2, which is the pressure detected by the first detection unit 36 ​​in step S13, to extract a first change amount, which is the change amount related to the pressure. Then, the control unit 35 judges whether or not the absolute value of the extracted first change amount "|F2-F1|" is equal to or greater than the first threshold value TH1 (step S14). If the judgment result of step S14 is NO (if the absolute value of the first change amount "|F2-F1|" does not satisfy the first threshold value TH1), the control unit 35 does not cause the image processing unit 34 to perform each image processing described below, and causes the image processing unit 34 to output the original data to the timing controller 32. If the judgment result of step S14 is YES, the control unit 35 judges whether or not the absolute value of the first change amount "|F2-F1|" is equal to or greater than the second threshold value TH2 (step S15). When the determination result of step S15 is NO (when the absolute value of the first change amount "|F2-F1|" is equal to or larger than the first threshold value TH1 and does not satisfy the second threshold value TH2), the control unit 35 executes a first image processing for selectively processing the original data for the first region A1 centered on the second pressing position P2 (step S16). In detail, in step S16, the control unit 35 extracts the first region A1 centered on the second pressing position P2, which is the pressing position detected by the second detection unit 37 in step S13, and causes the image processing unit 34 to process the original data in the first region A1. Then, the control unit 35 causes the image processing unit 34 to output, as processed data, first data having a display gradation lower than that of the original data for the first region A1. When the first image processing is executed in this manner, the timing controller 32 performs display in the first region A1 at a display gradation based on the first data. This makes it possible to make it difficult to visually recognize display defects that may be visually recognized at the moment when the pressing force changes.

[0033] When the determination result of step S15 is YES (when the absolute value of the first change amount "|F2-F1|" is equal to or greater than the second threshold value TH2), the control unit 35 executes a second image process to selectively process the original data for the second region A2 centered on the second pressing position P2 (step S17). In detail, in step S17, the control unit 35 extracts the second region A2 centered on the second pressing position P2, which is the pressing position detected by the second detection unit 37 in step S13, and wider than the first region A1, and causes the image processing unit 34 to process the original data in the second region A2. Then, the control unit 35 causes the image processing unit 34 to output, as processed data, second data for the second region A2, which has a display gradation lower than the original data and a display gradation lower than the first data. When the second image process is executed in this manner, the timing controller 32 displays the second region A2 at a display gradation based on the second data. As a result, even if the pressure changes more significantly, a display with a lower display gradation is performed over a wider range, so that a display that more accurately reflects the instantaneous change in pressure can be realized.

[0034] As described above, the liquid crystal display device (display device) 10 of this embodiment includes a liquid crystal panel (display panel) 11 having a display surface 11A, a timing controller (image display unit) 32 that displays an image on the display surface 11A, an image processing unit 34 that is capable of processing original data related to the image and outputting the processed data to the timing controller 32, a first detection unit 36 ​​that detects a pressing force acting on the display surface 11A, a second detection unit 37 that detects a pressing position on the display surface 11A where the pressing force acts, and a control unit 35 that controls the image processing unit 34. The first detection unit 36 ​​and the second detection unit 37 detect the pressing force and the pressing position every unit time, and the control unit 35 controls the image processing unit 34. 5 extracts a first change amount, which is the change in pressure, by subtracting the pressure detected by the first detection unit 36 ​​at a first point in time from the pressure detected by the first detection unit 36 ​​at a second point in time when a unit time has elapsed from the first point in time, and if the absolute value of the extracted first change amount is equal to or greater than a first threshold value TH1, causes the image processing unit 34 to process the original data in a first area A1 centered on the pressure position detected by the second detection unit 37 at least at the second point in time and output first data having a lower display gradation than the original data as processed data, and if the absolute value of the first change amount is less than the first threshold value TH1, causes the image processing unit 34 to output the original data.

[0035] The pressure acting on the display surface 11A and the pressure position are detected by the first detection unit 36 ​​and the second detection unit 37 every unit time. Therefore, the control unit 35 can extract a first change amount, which is a change amount related to the pressure, by subtracting the pressure detected by the first detection unit 36 ​​at a first time point from the pressure detected by the first detection unit 36 ​​at a second time point when a unit time has elapsed from the first time point. If the absolute value of the extracted first change amount is equal to or greater than the first threshold value TH1, the control unit 35 causes the image processing unit 34 to perform the following process. That is, the image processing unit 34 processes the original data in the first region A1 centered on the pressure position detected by the second detection unit 37 at least at the second time point, and outputs the first data having a display gradation lower than that of the original data as the processed data. As a result, the first region A1 is displayed with a display gradation based on the processed first data, so that display defects that may be visible at the moment when the pressure changes can be made less visible. Compared to the conventional method of detecting the strength of pressure based on the amount of change in pressure from a state where no pressure is applied, this method can realize a display that accurately reflects the instantaneous change in pressure, and can obtain excellent display quality. If the first amount of change is less than the first threshold value TH1, the control unit 35 does not allow the image processing unit 34 to process the original data, and instead causes the original data to be output to the timing controller 32.

[0036] In addition, when the first change amount does not exceed the second threshold TH2 that is larger than the first threshold TH1 and is equal to or greater than the first threshold TH1, the control unit 35 causes the image processing unit 34 to process the original data in the first region A1 and output the first data as processed data, and when the first change amount is equal to or greater than the second threshold TH2, the control unit 35 causes the image processing unit 34 to process the original data in the second region A2 that is wider than the first region A1 and has the pressing position detected by the second detection unit 37 at least at the second time point as its center and outputs second data having a lower display gradation than the first data as processed data. The control unit 35 causes the image processing unit 34 to perform different processes depending on whether the first change amount is equal to or greater than the first threshold TH1 and does not exceed the second threshold TH2 or whether the first change amount is equal to or greater than the second threshold TH2. That is, when the first change amount is equal to or greater than the first threshold TH1 and does not exceed the second threshold TH2, the image processing unit 34 processes the original data in the first region A1 and outputs first data having a lower display gradation than the original data as processed data. On the other hand, when the first amount of change is equal to or greater than the second threshold TH2, the image processor 34 processes the original data in the second area A2, which is larger than the first area A1, and outputs, as the processed data, second data having a lower display gradation than the first data. In other words, when the pressure changes more significantly, a display with a lower display gradation is performed over a wider range, thereby realizing a display that more accurately reflects the instantaneous change in pressure.

[0037] <Embodiment 2> A second embodiment will be described with reference to Fig. 9 or 10. In this second embodiment, a case will be described in which the pressing force is corrected based on the inclination of a stylus pen 131. Note that a duplicated description of the structure, action, and effect similar to those of the first embodiment will be omitted.

[0038] 9, the stylus pen 131 according to this embodiment has a first detection unit 136 that detects a pressure acting on the display surface 111A. In addition, the stylus pen 131 has a third detection unit 38 that detects the tilt angle of the stylus pen 131 with respect to the display surface 111A. As shown in FIG. 10, this tilt angle is the angle between the display surface 111A and an axis 131AX (shown by a dashed line in FIG. 10) of the stylus pen 131. The touch controller 133 has a second detection unit 137.

[0039] If the stylus pen 131 has the first detection unit 136 as in this embodiment, the following problem may occur. That is, the pressure detected by the first detection unit 136 is a pressure acting on the display surface 111A along the axis 131AX of the stylus pen 131, as shown in FIG. 10. Therefore, when the axis 131AX of the stylus pen 131 is inclined with respect to the display surface 111A, the pressure detected by the first detection unit 136 becomes a value different from the pressure acting from the stylus pen 131 to the display surface 111A along the normal direction of the display surface 111A. Therefore, if the first change amount is extracted based on the pressure detected by the first detection unit 136 of the stylus pen 131, there is a risk of erroneous determination occurring when determining whether the first change amount is equal to or greater than the first threshold value TH1.

[0040] Therefore, when the tilt angle detected by the third detection unit 38 is "θ", the control unit 135 according to this embodiment multiplies the pressure detected by the first detection unit 136 by "sinθ" to calculate a corrected pressure, and extracts a first change amount based on the corrected pressure. In detail, as shown in FIG. 10, when the pressure acting on the display surface 111A along the axis 131AX of the stylus pen 131 is "F", and the pressure acting along the normal direction of the display surface 111A is "F'", the formula "F'=F·sinθ" is established. In this formula, "F" corresponds to the pressure detected by the first detection unit 136, and "F'" corresponds to the corrected pressure. Based on this, the control unit 135 calculates a first corrected pressure by multiplying the first pressure detected by the first detection unit 136 at the first time point by "sinθ", and calculates a second corrected pressure by multiplying the second pressure detected by the first detection unit 136 at the second time point by "sinθ". Then, the control unit 135 extracts a first change amount by subtracting the first corrected pressure from the second corrected pressure. This makes it possible to appropriately obtain the first change amount, which is a change amount related to the pressure acting on the display surface 111A along the normal direction of the display surface 111A, even if the stylus pen 131 is inclined with respect to the display surface 111A. Therefore, it is difficult for a situation to occur in which an erroneous determination occurs when determining whether the first change amount is equal to or greater than the first threshold value TH1, and the image processing unit 134 can output the first data of an appropriate display gradation.

[0041] As described above, according to this embodiment, the stylus pen 131 applies a pressure to the display surface 111A, and the third detection unit 38 detects the inclination angle of the stylus pen 131 with respect to the display surface 111A. The stylus pen 131 has the first detection unit 136. When the inclination angle detected by the third detection unit 38 is "θ", the control unit 135 multiplies the pressure detected by the first detection unit 136 by "sinθ" to calculate a corrected pressure, and extracts a first change amount based on the corrected pressure. The pressure detected by the first detection unit 136 of the stylus pen 131 acts on the display surface 111A along the axis 131AX of the stylus pen 131. Here, when the stylus pen 131 is inclined with respect to the display surface 111A, the pressure acting on the display surface 111A along the normal direction of the display surface 111A becomes a different value from the pressure acting on the display surface 111A along the axis 131AX of the stylus pen 131. Therefore, the control unit 135 calculates a corrected pressure by multiplying the pressure detected by the first detection unit 136 by "sinθ" based on the tilt angle "θ" detected by the third detection unit 38. The calculated corrected pressure coincides with the pressure acting on the display surface 111A along the normal direction of the display surface 111A. Then, the control unit 135 extracts the first change amount by subtracting the corrected pressure calculated by multiplying the pressure detected by the first detection unit 136 at the first time point by "sinθ" from the corrected pressure calculated by multiplying the pressure detected by the first detection unit 136 at the second time point by "sinθ". As a result, even if stylus pen 131 is tilted with respect to display surface 111A, the amount of change in the pressure acting on display surface 111A along the normal direction of display surface 111A can be appropriately obtained, so that image processing unit 134 can output first data with an appropriate display gradation.

[0042] <Embodiment 3> A third embodiment will be described with reference to Fig. 11 to Fig. 15. In this third embodiment, a case is shown in which it is determined whether or not to perform image processing based on the amount of change related to the pressing position, unlike the first embodiment. Note that a duplicated description of the structure, action, and effect similar to those of the first embodiment will be omitted.

[0043] As shown in FIG. 11, the liquid crystal display device 210 according to this embodiment has almost the same configuration as the liquid crystal display device 10 described in the above-mentioned embodiment 1. In this embodiment, the control unit 235 extracts a second change amount, which is a change amount related to the pressed position, by subtracting a first pressed position, which is a pressed position detected by the second detection unit 237 at a certain timing (hereinafter referred to as a first time point), from a second pressed position, which is a pressed position detected by the second detection unit 237 at a second time point after a unit time has elapsed from the first time point. When the first pressed position is "P1" and the second pressed position is "P2", the second change amount can be expressed as "P2-P1". When "P2-P1" is a positive value, the direction in which the pressed position changes is opposite to that when it is a negative value.

[0044] Here, the change in the pressing position will be described with reference to FIG. 12 to FIG. 14. First, when the pressing force applied to the counter substrate 220 by the user exceeds a predetermined value, as shown in FIG. 12, the counter substrate 220 is bent near the pressed portion. In this state, when the pressing position by the user moves from the first pressing position P1 shown in FIG. 12 to the second pressing position P2 shown in FIG. 13, there is a risk that a display defect caused by the pressing will be visually recognized along the moving path. When the amount of movement from the first pressing position P1 to the second pressing position P2 is larger than that in FIG. 13, as shown in FIG. 14, the range in which the display defect is visually recognized becomes wider than that in FIG. 13, and the change in the display gradation also tends to be larger. Note that the polarizing plate 15 (see FIG. 2) is omitted in FIG. 12 to FIG. 14. Also, although FIG. 12 to FIG. 14 illustrate a case in which the display surface 211A is pressed by the stylus pen 231, the display surface 211A may be pressed by other position input objects including a finger.

[0045] Then, the control unit 235 according to the present embodiment judges whether the absolute value of the extracted second change amount is equal to or greater than a predetermined third threshold value TH3, and judges whether the second pressing force F2, which is the pressing force detected by the first detection unit 236 at the second time point, is equal to or greater than a fourth threshold value TH4. Here, the third threshold value TH3 and the fourth threshold value TH4, which are the judgment criteria, are both values ​​empirically found to be values ​​at which display defects occurring near the pressed location due to pressing can be visually recognized. If the judgment result is "YES", the control unit 235 causes the image processing unit 234 to process the original data in the third region A3, which is a range spanning the first pressing position P1 and the second pressing position P2, and outputs third data having a lower display gradation than the original data as processed data. As shown in FIG. 13, this third region A3 is a range in which display defects can be visually recognized due to bending of the opposing substrate 220 near the pressed location, and is, for example, a band-like range in plan view centered on a line connecting the first pressing position P1 and the second pressing position P2. The timing controller 232 performs display in the third area A3 with a display gradation based on the third data output from the image processor 234, so that display defects that may be visible at the moment the pressing position changes can be made less visible. Compared to the conventional case where the strength of the pressing force is detected based on the amount of change in pressing force from a state where no pressing force is applied, a display that accurately reflects the instantaneous change in the pressing position can be realized, and excellent display quality can be obtained. If the determination result is "NO", the control unit 235 does not cause the image processor 234 to process the original data, but causes the original data to be output to the timing controller 232.

[0046] In addition, the control unit 235 also performs a determination based on a fifth threshold TH5, which is larger than the third threshold TH3, with respect to the second change amount. The fifth threshold TH5, which is the determination criterion, is a value empirically found such that the change in display gradation occurring near the pressed location due to pressing is large and the range in which display defects are visually recognized is wide. Specifically, when the second change amount does not exceed the fifth threshold TH5 but is equal to or greater than the third threshold TH3, the control unit 235 causes the image processing unit 234 to process the original data in the third region A3 and output the third data as processed data. On the other hand, when the second change amount is equal to or greater than the fifth threshold TH5, the control unit 235 causes the image processing unit 234 to process the original data in the fourth region A4, which is a range spanning the first pressing position P1 and the second pressing position P2 and is wider than the third region A3, and output the fourth data, which has a display gradation lower than the third data, as processed data. 14, the fourth region A4 is a range in which a display defect may be visually recognized due to bending of the counter substrate 220 near the pressed position, and is, for example, a band-like range in a plan view centered on a line connecting the first pressing position P1 and the second pressing position P2, and its length is greater than that of the third region A3. In this way, when the pressing position changes more significantly, a display with a lower display gradation is performed over a wider range, so that a display that more accurately reflects the instantaneous change in the pressing position can be realized.

[0047] Next, a specific process performed in association with touch detection will be described with reference to the flowchart shown in FIG. 15. According to FIG. 15, when the liquid crystal display device 210 is powered on, the control unit 235 judges whether or not a touch has been detected (step S20). If the judgment result of step S20 is NO, the process returns to step S20, and the control unit 235 judges again whether or not a touch has been detected. If the judgment result of step S20 is YES, the control unit 235 causes the first detection unit 236 and the second detection unit 237 provided in the touch controller 233 to detect the pressing force and the pressing position, respectively (step S21). Then, the control unit 235 judges whether or not a unit time has elapsed (step S22). If the judgment result of step S22 is NO, the process returns to step S22, and the control unit 235 judges whether or not a unit time has elapsed. If the judgment result of step S22 is YES, the control unit 235 causes the first detection unit 236 and the second detection unit 237 to detect the pressing force and the pressing position, respectively, again (step S23). The timing when step S21 is performed is a "first time point", and the timing when step S23 is performed is a "second time point" when a unit time has elapsed since the "first time point".

[0048] The control unit 235 subtracts the first pressing position P1, which is the pressing position detected by the second detection unit 237 in step S21, from the second pressing position P2, which is the pressing position detected by the second detection unit 237 in step S23, to extract a second change amount, which is the change amount related to the pressing position. Then, the control unit 235 determines whether the absolute value of the extracted second change amount "|P2-P1|" is equal to or greater than a third threshold value TH3, and determines whether the second pressing force F2, which is the pressing force detected by the first detection unit 236 at the second time point, is equal to or greater than a fourth threshold value TH4 (step S24). If the determination result of step S24 is NO (if the absolute value of the second change amount "|P2-P1|" is less than the third threshold TH3 or if the second pressing force F2 is less than the fourth threshold TH4), the control unit 235 does not cause the image processing unit 234 to perform each image processing described below, and causes the image processing unit 234 to output the original data to the timing controller 232. If the determination result of step S24 is YES, the control unit 235 determines whether the absolute value of the second change amount "|P2-P1|" is equal to or greater than the fifth threshold TH5 (step S25). If the determination result of step S25 is NO (if the absolute value of the second change amount "|P2-P1|" is equal to or greater than the third threshold TH3 and less than the fifth threshold TH5), the control unit 235 executes the first image processing to selectively process the original data for the third region A3, which is a range spanning the first pressing position P1 and the second pressing position P2 (step S26). In detail, in step S26, the control unit 235 extracts a third region A3 that is a range that spans the first pressing position P1 detected by the second detection unit 237 in step S21 and the second pressing position P2 detected by the second detection unit 237 in step S23, and causes the image processing unit 234 to process the original data in the third region A3. Then, the control unit 235 causes the image processing unit 234 to output third data having a lower display gradation than the original data as processed data for the third region A3. When the first image processing is executed in this manner, the timing controller 232 displays the third region A3 at a display gradation based on the third data. This makes it possible to make it difficult to view display defects that may be visible at the moment the pressing position changes.

[0049] When the determination result of step S25 is YES (when the absolute value of the second change amount "|P2-P1|" is equal to or greater than the fifth threshold value TH5), the control unit 235 executes a second image process to selectively process the original data for the fourth region A4, which is a range spanning the first pressing position P1 and the second pressing position P2 (step S27). In detail, in step S27, the control unit 235 extracts the fourth region A4, which is a range spanning the first pressing position P1 and the second pressing position P2 and is wider than the third region A3, and causes the image processing unit 234 to process the original data in the fourth region A4. Then, the control unit 235 causes the image processing unit 234 to output, as processed data, fourth data for the fourth region A4, which has a display gradation lower than the original data and a display gradation lower than the third data. When the second image process is executed in this manner, the timing controller 232 displays the fourth region A4 at a display gradation based on the fourth data. As a result, even if the pressed position changes significantly, a display with a lower display gradation is performed over a wider range, so that a display that more accurately reflects the instantaneous change in the pressed position can be realized.

[0050] As described above, the liquid crystal display device 210 according to this embodiment includes a liquid crystal panel 211 having a display surface 211A, a timing controller 232 that displays an image on the display surface 211A, an image processing unit 234 that is capable of processing original data relating to the image and outputting the processed data to the timing controller 232, a first detection unit 236 that detects a pressing force acting on the display surface 211A, a second detection unit 237 that detects a pressing position on the display surface 211A where the pressing force acts, and a control unit 235 that controls the image processing unit 234. The first detection unit 236 and the second detection unit 237 detect the pressing force and the pressing position every unit time, and the control unit 235 calculates a pressing position P1 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P2 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P3 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P4 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P5 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P6 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P7 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P8 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P9 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P1 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P1 that is a pressing position detected by the second detection unit 237 at a first time point and a pressing position P8 that is a pressing position detected by the second detection unit 237 at a and extracting a second change amount, which is the change amount related to the pressing position, based on the second pressing position P2, which is the pressing position detected by the second detection unit 237 at a second time point after 100 seconds has elapsed, and if the absolute value of the extracted second change amount is equal to or greater than the third threshold value TH3 and the pressing force detected by the first detection unit 236 at the second time point is equal to or greater than the fourth threshold value TH4, causing the image processing unit 234 to process the original data in a third area A3, which is a range straddling at least the first pressing position P1 and the second pressing position P2, and output third data having a lower display gradation than the original data as processed data; and if the second change amount is less than the third threshold value TH3 or if the pressing force detected by the first detection unit 236 at the second time point is less than the fourth threshold value TH4, causing the image processing unit 234 to output the original data.

[0051] The pressure acting on the display surface 211A and its pressure position are detected every unit time by the first detection unit 236 and the second detection unit 237. Therefore, the control unit 235 can extract a second change amount, which is a change amount related to the pressure position, based on the first pressure position P1, which is a pressure position detected by the second detection unit 237 at a first time point, and the second pressure position P2, which is a pressure position detected by the second detection unit 237 at a second time point when a unit time has elapsed from the first time point. If the extracted second change amount is equal to or greater than the third threshold TH3 and the pressure detected by the first detection unit 236 at the second time point is equal to or greater than the fourth threshold TH4, the control unit 235 causes the image processing unit 234 to perform the next process. That is, the image processing unit 234 processes the original data in the third region A3, which is a range spanning at least the first pressure position P1 and the second pressure position P2, and outputs third data having a lower display gradation than the original data as processed data. As a result, the third area A3 is displayed with a display gradation based on the processed third data, so that display defects that may be visible at the moment when the pressing position changes can be made difficult to see. Compared to the conventional case where the strength of the pressing force is detected based on the amount of change in the pressing force from a state where no pressing force is applied, a display that accurately reflects the instantaneous change in the pressing position can be realized, and excellent display quality can be obtained. Note that, when the second amount of change is less than the third threshold value TH3 or when the pressing force detected by the first detection unit 236 at the second time point is less than the fourth threshold value TH4, the control unit 235 does not cause the image processing unit 234 to process the original data, and causes the original data to be output to the timing controller 232.

[0052] Furthermore, when the second amount of change does not exceed a fifth threshold TH5 that is greater than the third threshold TH3 but is equal to or greater than the third threshold TH3, the control unit 235 causes the image processing unit 234 to process the original data in the third region A3 and output the third data as processed data, and when the second amount of change is equal to or greater than the fifth threshold TH5, the control unit 235 causes the image processing unit 234 to process the original data in a fourth region A4 that is wider than the third region A3 and that spans at least the first pressing position P1 and the second pressing position P2, and outputs the fourth data having a lower display gradation than the third data as processed data. The control unit 235 causes the image processing unit 234 to perform different processes depending on whether the second amount of change is equal to or greater than the third threshold TH3 and does not exceed the fifth threshold TH5 or whether the second amount of change is equal to or greater than the fifth threshold TH5. That is, when the second amount of change is equal to or greater than the third threshold TH3 and does not exceed the fifth threshold TH5, the image processor 234 processes the original data in the third region A3, and outputs, as the processed data, third data having a lower display gradation than the original data. On the other hand, when the second amount of change is equal to or greater than the fifth threshold TH5, the image processor 234 processes the original data in the fourth region A4, which is wider than the third region A3, and outputs, as the processed data, fourth data having a lower display gradation than the third data. That is, when the pressing position changes more significantly, a display with a lower display gradation is performed over a wider range, so that a display that more accurately reflects the instantaneous change in the pressing position can be realized.

[0053] <Embodiment 4> A fourth embodiment will be described with reference to Fig. 16. In this fourth embodiment, the range of image processing is changed from that of the third embodiment. Note that duplicated descriptions of structures, actions, and effects similar to those of the third embodiment will be omitted.

[0054] First, as in the above-described third embodiment, when the pressing position by the user moves, the range in which display defects caused by the pressing force can be seen from the first pressing position P1 to the second pressing position P2 at the second time point may tend to gradually widen as the area approaches from the first pressing position P1 to the second pressing position P2, as shown in FIG. 16. Assuming such a case, the control unit 35 according to this embodiment sets the fifth area A5, which is the area in which image processing is performed, as follows, as shown in FIG. 16. That is, the control unit 35 causes the image processing unit 34 to process the original data in the fifth area A5, which includes the third area A3 described in the third embodiment and whose range gradually widens as the area approaches from the first pressing position P1 to the second pressing position P2, and output the third data or the fourth data. In FIG. 16, the fifth area A5 is illustrated by being hatched. The fifth region A5 has a planar shape that is wider on the second pressing position P2 side than on the first pressing position P1 side, and has a minimum width near the first pressing position P1 and a maximum width near the second pressing position P2. This makes it difficult for display defects to be clearly seen in the fifth region A5.

[0055] As described above, according to this embodiment, the control unit 35 causes the image processing unit 34 to process the original data in the fifth region A5 including the third region A3, the range of which gradually becomes wider as the image moves from the first pressing position P1 to the second pressing position P2, and output the third data or the fourth data. At the second time point, there is a risk that a display defect caused by the pressing force may be visually recognized from the first pressing position P1 to the second pressing position P2, and the range in which the display defect may occur tends to gradually become wider as the image processing unit 34 moves from the first pressing position P1 to the second pressing position P2. In this regard, the image processing unit 34 processes the original data in the fifth region A5, the range of which gradually becomes wider as the image processing unit 34 moves from the first pressing position P1 to the second pressing position P2 and from the first pressing position P1 to the second pressing position P2, and outputs the third data or the fourth data, so that the display defect is less likely to be visually recognized in the fifth region A5.

[0056] <Embodiment 5> A fifth embodiment will be described with reference to Fig. 17. In this fifth embodiment, an image processing unit 434 is modified from the first embodiment. Note that a duplicated description of the structure, action, and effect similar to those of the first embodiment will be omitted.

[0057] Image processing unit 434 according to this embodiment is incorporated in host system HS as shown in Fig. 17. Even with this configuration, control unit 435 can cause image processing unit 434 included in host system HS to perform appropriate image processing, thereby realizing a display that accurately reflects instantaneous changes in pressure.

[0058] <Other embodiments> The technology disclosed in this specification is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included in the technical scope.

[0059] (1) If the result of the judgment in steps S14 and S24 of the flow chart shown in Figures 8 and 15 is "NO," the control unit 35, 135, 235, 435 judges whether the pressure detected by the first detection unit 36, 136, 236 at the second time point is equal to or greater than a predetermined value, and if the judgment result is "YES," it is also possible to have the image processing unit 34, 134, 234, 434 process the original data in the area centered on the pressure position detected by the second detection unit 37, 137, 237 at the second time point and output processed data with a lower display gradation than the original data. In this way, even if there is no change or only a slight change in the pressure or pressure position, display defects caused by the action of the pressure are less likely to be visually recognized.

[0060] (2) In the configurations described in the first, third, fourth and fifth embodiments, the first detection unit 36, 236 may be provided in the stylus pen 31.

[0061] (3) In the configuration described in the third embodiment, the third detection unit 38 may be provided in a component other than the stylus pen 231.

[0062] (4) The specific value of the "unit time" can be changed appropriately to values ​​other than those exemplified in the first embodiment.

[0063] (5) The planar shape of the liquid crystal panel 11 may be a vertically long rectangle, a square, a circle, a semicircle, an oval, an ellipse, a trapezoid, or the like.

[0064] (6) The liquid crystal panel 11 may be of a reflective or semi-transmissive type other than a transmissive type.

[0065] (7) In the configurations described in the first, second and fifth embodiments, the control unit 35, 135, 435 may determine the absolute value of the first amount of change in pressure based on three or more threshold values.

[0066] (8) In the configurations described in the third and fourth embodiments, the control unit 235 may determine the absolute value of the second amount of change in the pressed position based on three or more threshold values.

[0067] (9) In addition to the in-cell type in which a touch panel pattern is integrated into liquid crystal panel 11, an out-cell type in which a touch panel is provided separately from liquid crystal panel 11 may also be used. In this case, a "display panel" is formed by liquid crystal panel 11 and a touch panel that is laminated on the front side of liquid crystal panel 11. The touch panel that constitutes the "display panel" has a display surface that displays an image, a first detection unit that detects a pressure acting on the display surface, and a second detection unit that detects a pressure position on the display surface where the pressure acts. [Explanation of symbols]

[0068] 10... liquid crystal display device (display device), 11... liquid crystal panel (display panel), 11A, 111A, 211A... display surface, 31, 131, 231... stylus pen, 32, 232... timing controller (image display unit), 34, 134, 234, 434... image processing unit, 35, 135, 235, 435... control unit, 36, 136, 236... first detection unit, 37, 137, 237... second detection unit, 38... third detection unit, A1... first region, A2... second region, A3... third region, A4... fourth region, A5... fifth region, P1... first pressing position, P2... second pressing position, TH1... first threshold, TH2... second threshold, TH3... third threshold, TH4... fourth threshold, TH5... fifth threshold

Claims

1. a display panel having a display surface; an image display unit that displays an image on the display surface; an image processing unit capable of processing original data relating to an image and outputting the processed data to the image display unit; A first detection unit that detects a pressing force acting on the display surface; a second detection unit that detects a pressing position on the display surface where the pressing force is applied; A control unit that controls the image processing unit, the first detection unit and the second detection unit detect the pressing force and the pressing position every unit time; The control unit extracts a first change amount, which is a change amount related to the pressure, by subtracting the pressure detected by the first detection unit at a first time point from the pressure detected by the first detection unit at a second time point after the unit time has elapsed from the first time point, and if the absolute value of the extracted first change amount is equal to or greater than a first threshold value, causes the image processing unit to process the original data in at least a first region centered on the pressure position detected by the second detection unit at the second time point and output first data having a lower display gradation than the original data as the processed data, and if the absolute value of the first change amount is less than the first threshold value, causes the image processing unit to output the original data.

2. The display device of claim 1, wherein the control unit, when the first change amount does not exceed a second threshold value that is greater than the first threshold value and is equal to or greater than the first threshold value, causes the image processing unit to process the original data in the first region and output the first data as the processed data, and when the first change amount is equal to or greater than the second threshold value, causes the image processing unit to process the original data in a second region that is centered on the pressure position detected by the second detection unit at least at the second time point and is wider than the first region, and outputs second data having a lower display gradation than the first data as the processed data.

3. a stylus pen that applies the pressing force to the display surface; a third detection unit that detects a tilt angle of the stylus pen with respect to the display surface, The stylus pen has the first detection unit, 3. The display device according to claim 1, wherein the control unit, when the tilt angle detected by the third detection unit is "θ", multiplies the pressure detected by the first detection unit by "sin θ" to calculate a corrected pressure, and extracts the first change amount based on the corrected pressure.

4. a display panel having a display surface; an image display unit that displays an image on the display surface; an image processing unit capable of processing original data relating to an image and outputting the processed data to the image display unit; A first detection unit that detects a pressing force acting on the display surface; a second detection unit that detects a pressing position on the display surface where the pressing force is applied; A control unit that controls the image processing unit, the first detection unit and the second detection unit detect the pressing force and the pressing position every unit time; The control unit extracts a second change amount, which is the amount of change related to the pressure position, based on a first pressure position, which is the pressure position detected by the second detection unit at a first time point, and a second pressure position, which is the pressure position detected by the second detection unit at a second time point when the unit time has elapsed from the first time point, and if the absolute value of the extracted second change amount is greater than or equal to a third threshold and the pressure detected by the first detection unit at the second time point is greater than or equal to a fourth threshold, causes the image processing unit to process the original data in a third region, which is a range spanning at least the first pressure position and the second pressure position, and output third data having a lower display gradation than the original data as the processed data, and if the second change amount is less than the third threshold or if the pressure detected by the first detection unit at the second time point is less than the fourth threshold, causes the image processing unit to output the original data.

5. The display device of claim 4, wherein the control unit, when the second amount of change does not exceed a fifth threshold value that is greater than the third threshold value and is equal to or greater than the third threshold value, causes the image processing unit to process the original data in the third region and output the third data as the processed data, and when the second amount of change is equal to or greater than the fifth threshold value, causes the image processing unit to process the original data in a fourth region that is at least in a range spanning the first pressing position and the second pressing position and is wider than the third region, and outputs fourth data having a lower display gradation than the third data as the processed data.

6. The display device according to claim 5, wherein the control unit causes the image processing unit to process the original data in a fifth region that includes the third region and whose range gradually widens as it approaches the second pressing position from the first pressing position, and output the third data or the fourth data.

Images