Terminal device and program

Abstract

To provide a terminal device and a program that enable residual indentation to be suppressed.SOLUTION: A terminal device comprises: a display unit that has a liquid crystal display panel in which a touch panel is provided; and control means that controls a display action of the display unit, the control means enables the display unit to operate in a first display mode displaying in first display gradation and in a second display mode displaying in second display gradation having a smaller gradation number than the first display gradation, and the control means causes the display unit to operate in the second display mode when it is determined that a predetermined indentation suppression condition is satisfied.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a terminal device and a program. [Background technology]

[0002] Conventionally, terminal devices (e.g., handheld terminals) having a liquid crystal display panel with a touch panel are known (e.g., Patent Document 1). In such terminal devices, the touch panel can detect a touch operation by a finger, a stylus, or the like on the display screen of the liquid crystal display panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-24654 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the pressure applied during the touch operation is too strong or if the liquid crystal display panel is subjected to an impact due to, for example, dropping the terminal device, pressure unevenness (pressure marks) may appear on the display screen. Although this pressure unevenness is usually temporary and is caused by a disturbance in the orientation of the liquid crystal molecules, if pressure unevenness remains on the display screen, there is a problem that the user may mistakenly believe that it is a malfunction of the display unit.

[0005] An object of the present invention is to provide a terminal device and a program capable of suppressing residual pressure unevenness. [Means for solving the problem]

[0006] In order to solve the above problem, one aspect of the terminal device of the present invention is to A display unit having a liquid crystal display panel provided with a touch panel; A control means for controlling a display operation of the liquid crystal display panel; An acceleration sensor; a detection means for detecting at least one of a drop of the device and a shock of a predetermined intensity applied to the device based on a detection result of the acceleration by the acceleration sensor; Equipped with The control means The liquid crystal display panel can be operated in any one of a first display mode in which a display is performed at a first display gradation and a second display mode in which a display is performed at a second display gradation having a smaller number of gradations than the first display gradation, operating the liquid crystal display panel in the second display mode when it is determined that a pressure unevenness suppression condition related to pressure unevenness occurring in the liquid crystal display panel due to pressing of the touch panel is satisfied; The second display gray scale level is obtained by subtracting from the first display gray scale level a gray scale range from a minimum gray scale level to a first gray scale number in the first display gray scale level. the law of nature, The control means determines that the pressure unevenness suppression condition is satisfied when at least one of the drop and the impact is detected by the detection means. Characterized by 。

[0007] In order to solve the above problems, one aspect of the program of the present invention is A display unit having a liquid crystal display panel provided with a touch panel an acceleration sensor; and detection means for detecting at least one of a drop of the device and a shock of a predetermined strength applied to the device based on a detection result of acceleration by the acceleration sensor. a computer provided in a terminal device functioning as a control unit for controlling a display operation of the liquid crystal display panel; The control means The liquid crystal display panel can be operated in any one of a first display mode in which a display is performed at a first display gradation and a second display mode in which a display is performed at a second display gradation having a smaller number of gradations than the first display gradation, operating the liquid crystal display panel in the second display mode when it is determined that a pressure unevenness suppression condition related to pressure unevenness occurring in the liquid crystal display panel due to pressing of the touch panel is satisfied; The second display gray scale level is obtained by subtracting from the first display gray scale level a gray scale range from a minimum gray scale level to a first gray scale number in the first display gray scale level. the law of nature, The control means determines that the pressure unevenness suppression condition is satisfied when at least one of the drop and the impact is detected by the detection means. It is characterized by: Effect of the Invention

[0008] According to the present invention, it is possible to suppress residual pressing unevenness. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a handheld terminal as a terminal device. [Diagram 2] FIG. 2 is a block diagram showing a functional configuration of the handheld terminal. [Diagram 3] FIG. 2 is a schematic cross-sectional view showing a configuration of a display unit. [Figure 4] 3A and 3B are diagrams illustrating display modes of a display unit. [Diagram 5] FIG. 13 is a diagram showing gradation values ​​used to display white, black, red, green, and blue colors in a normal mode and a gradation limited mode. [Figure 6] 5A and 5B are diagrams illustrating examples of waveform patterns of voltages applied to a liquid crystal layer. [Figure 7] 13 is a flowchart showing a control procedure of a first display control process. [Figure 8] FIG. 11 is a diagram showing an example of the contents of display mode setting data. [Figure 9] 13 is a flowchart showing a control procedure of a second display control process. [Figure 10] 13 is a flowchart showing a control procedure of a third display control process. [Figure 11] 11A and 11B are diagrams illustrating examples of patterns of acceleration detection results when a drop is detected and when an impact is detected. [Figure 12] 13 is a flowchart showing a control procedure of a fourth display control process. [Figure 13] 13 is a flowchart showing a control procedure of a fifth display control process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a terminal device and a program according to the present invention will be described with reference to the drawings.

[0011] (Handheld terminal configuration) FIG. 1 is a diagram showing a handheld terminal 1 serving as a terminal device. The handy terminal 1 is installed in a store, warehouse, or other such location, and is operated by an operator such as a store clerk or manager at the location. The handy terminal 1 includes a display unit 15 located on the front, various operation keys 16 located on the front, sides, rear, and other locations, and a barcode scanner 19 (see FIG. 2) that scans and reads symbols such as barcodes. The display unit 15 displays an operation screen in response to operations using the operation keys 16, information read by the barcode scanner 19, and the like. The handy terminal 1 also includes a communication unit 20 (see FIG. 2) that performs wireless LAN communication with an access point, and transmits information read by the barcode scanner 19 to a specified server via the access point.

[0012] FIG. 2 is a block diagram showing the functional configuration of the handheld terminal 1. As shown in FIG. The handy terminal 1 includes a CPU 11 (Central Processing Unit) (computer), a RAM 12 (Random Access Memory), a ROM 13 (Read Only Memory), a storage unit 14, a display unit 15, operation keys 16, a pressure sensor 17, an acceleration sensor 18, a barcode scanner 19, a communication unit 20, and a bus 21. The various units of the handy terminal 1 are connected to each other via the bus 21. In addition to these components, the handy terminal 1 may also include a camera for acquiring images and notification means such as a buzzer and an LED (Light Emitting Diode).

[0013] The CPU 11 is a processor that controls each part of the handheld terminal 1 by performing various processes according to a program 141 stored in the storage unit 14. The CPU 11 executes the program 141 to perform various processes, thereby functioning as a control means that controls the display operation of the display unit, a user identification means that identifies the user operating the handheld terminal 1, a detection means that detects a fall or impact, and the like.

[0014] The RAM 12 provides a working memory space for the CPU 11 and stores temporary data. The RAM 12 may include a non-volatile memory.

[0015] The ROM 13 is a non-volatile storage unit from which information can be read, and stores various setting data and the like.

[0016] The storage unit 14 includes a storage device capable of writing and reading data, such as a solid state drive (SSD) having a flash memory, and stores a program 141 and various data. The data stored in the storage unit 14 includes data of the reading result by the barcode scanner 19, display mode setting data 142 (display mode setting information), and user authentication data 143 used in user authentication processing. The contents of the display mode setting data 142 will be described later. The user authentication data 143 is data in which a password set by a user is associated with a user ID unique to the user, for example.

[0017] The display unit 15 has a touch panel 151, a liquid crystal display panel 152, and a backlight 153. The display unit 15 displays various operation screens and the like in response to control signals transmitted from the CPU 11. The configuration and operation of the display unit 15 will be described in detail later.

[0018] The operation keys 16 are pressed by a user. The operation keys 16 include character input keys for inputting numbers and letters, function keys for calling and executing a predetermined function, and a trigger key for starting a reading operation of the barcode scanner 19. When an operation key 16 is pressed, an operation signal according to the function of that operation key 16 is transmitted to the CPU 11 and accepted as an input operation.

[0019] The pressure sensor 17 is provided in the display unit 15 , and detects the pressure applied to the liquid crystal display panel 152 and transmits the detection result to the CPU 11 .

[0020] The acceleration sensor 18 detects the acceleration of the handheld terminal 1 and transmits the detection result to the CPU 11. From this detection result, it is possible to detect whether the handheld terminal 1 has been dropped, an impact applied to the handheld terminal 1, and the like.

[0021] The barcode scanner 19 reads a symbol such as a barcode or a two-dimensional code generated according to a predetermined rule, decodes the obtained signal, and outputs the signal to the CPU 11. At least a part of the decoding process may be executed by the CPU 11. The barcode scanner 19 emits a laser beam from a reading surface provided on the rear surface of the handy terminal 1, and reads a symbol based on the intensity distribution of the reflected light of the laser beam on the surface of the object to be read.

[0022] The communication unit 20 is a communication module having an antenna, a modulation / demodulation circuit, a signal processing circuit, etc., and performs communication control in accordance with a communication standard related to wireless communication by wireless LAN. Under the control of the CPU 11, the communication unit 20 performs wireless communication with an access point that is set in advance as a communication connection target, and transmits and receives data to and from a server via the access point.

[0023] (Display Configuration and Operation) Next, the detailed configuration and operation of the display unit 15 will be described. FIG. 3 is a schematic cross-sectional view showing the configuration of the display unit 15. As shown in FIG. The display unit 15 includes a liquid crystal display panel 152, a touch panel 151 provided on the display surface side of the liquid crystal display panel 152, a backlight 153 provided on the rear surface side of the liquid crystal display panel 152, and the like.

[0024] Touch panel 151 detects the contact and contact position of an operating means such as a user's finger or a stylus (below, an example in which a finger is used will be described) on the surface (operation surface) of display unit 15, and transmits the detection result to CPU 11. The detection method of touch panel 151 is not particularly limited, but may be, for example, a capacitance method or a resistive film method.

[0025] The backlight 153 is a surface light source that irradiates light onto the entire surface of the liquid crystal display panel 152. Of the light emitted from the backlight 153 toward the liquid crystal display panel 152, the light that has passed through the liquid crystal display panel 152 and the touch panel 151 is used to display the display unit 15. The backlight 153 has, for example, a plurality of LEDs and a light guide plate that guides the light emitted from these LEDs to the inside and reflects it toward the liquid crystal display panel 152. By increasing or decreasing the amount of current flowing through the LEDs, the emission luminance of the backlight 153 can be adjusted, and thus the display luminance of the display unit 15 can be adjusted. The emission luminance of the backlight 153 is controlled by the CPU 11.

[0026] The liquid crystal display panel 152 has two glass substrates 1521 and 1524 bonded together via a spacer 1523, and a liquid crystal layer 1522 sealed between the glass substrates 1521 and 1524. Of the two glass substrates, the glass substrate 1521 is located on the rear side, and the glass substrate 1524 is located on the display surface side. Polarizing plates are attached to the outer surfaces of the glass substrates 1521 and 1524, respectively, with their polarization axes perpendicular to each other.

[0027] Transparent electrodes are provided on the inner surfaces of the glass substrates 1521 and 1524. When a voltage is applied between these electrodes, the orientation state of the liquid crystal molecules in the liquid crystal layer 1522 changes according to the magnitude of the applied voltage. The polarization state of the light emitted from the backlight 153, transmitted through the polarizing plate on the rear side, and entered the liquid crystal layer 1522 changes according to the orientation state of the liquid crystal molecules in the liquid crystal layer 1522. The light that passes through the liquid crystal layer 1522 is absorbed by the polarizing plate on the display surface side or transmitted through the polarizing plate according to the polarization state at the time of passing through. More specifically, when no voltage is applied to the liquid crystal layer 1522, the polarization state (linear polarization) of the incident light hardly changes in the liquid crystal layer 1522, and is absorbed by the polarizing plate on the display surface side whose polarization axis is perpendicular to the light. On the other hand, when a predetermined voltage Vd (a voltage corresponding to the maximum gray scale described later) is applied to the liquid crystal layer 1522, the incident linearly polarized light is converted to linearly polarized light perpendicular to the linearly polarized light or elliptically polarized light, and a part of the light emitted from the liquid crystal layer 1522 is transmitted through the polarizer on the display surface side. By adjusting the applied voltage signal to set the orientation state of the liquid crystal layer 1522 to an intermediate state between the no voltage application state and the state in which the voltage Vd is applied, a halftone display can be performed with the amount of transmitted light from the polarizer on the display surface side set to an intermediate value. By controlling the orientation state of the liquid crystal layer 1522 (i.e., the voltage signal applied to the liquid crystal layer 1522) for each pixel, the amount of transmitted light from each pixel can be adjusted. By adjusting the amount of transmitted light from each pixel arranged in a matrix, a desired display can be performed on the liquid crystal display panel 152.

[0028] As described above, the liquid crystal display panel 152 of the present embodiment is a normally black mode in which the panel is in a dark state when no voltage is applied and in a bright state when a voltage is applied. However, the present invention is not limited to this, and the panel may be a normally white mode in which the panel is in a bright state when no voltage is applied.

[0029] A color filter that transmits R (red), G (green) or B (blue) light is provided on the opposing surfaces of the glass substrates 1521 and 1524 for each pixel. Therefore, each pixel displays one of the colors R, G or B according to the color of the color filter. In addition, any color can be expressed by combining adjacent R, G and B pixels.

[0030] The configuration and driving method of the electrodes in the liquid crystal display panel 152 are not particularly limited, but may be, for example, an active matrix type. In the active matrix type, an electrode (pixel electrode) is provided for each pixel on one side of the glass substrate 1521, and an electrode (common electrode) common to all pixels is provided on the other side. In addition, a switching element connected to the pixel electrode switches between supplying and stopping the power supply voltage to each pixel electrode. This allows the voltage applied to the liquid crystal layer 1522 of each pixel to be individually controlled.

[0031] The liquid crystal display panel 152 is provided with a driver IC (Integrated Circuit) (not shown). The driver IC generates a power supply voltage to be supplied to the pixel electrodes and the common electrode, and switches on / off the switching elements of each pixel in response to a control signal transmitted from the CPU 11, thereby performing display on the liquid crystal display panel 152.

[0032] The alignment method of the liquid crystal layer 1522 may be, for example, a Twisted Nematic (TN) method, but is not limited to this, and any other alignment method such as an In-Plane Switching (IPS) method or a Vertical Alignment (VA) method may be used.

[0033] FIG. 4 is a diagram for explaining the display modes of the display unit 15. As shown in FIG. The display unit 15 of this embodiment operates in one display mode designated by the CPU 11, between a normal mode (first display mode) in which each pixel performs display in a first display gradation, and a gradation restriction mode (second display mode) in which each pixel performs display in a second display gradation having fewer gradations than the first display gradation. In other words, the CPU 11 can operate the display unit 15 in any one of the normal mode and the gradation restriction mode, and can switch to the other display mode at any timing. Furthermore, when the CPU 11 determines that a predetermined pressure unevenness suppression condition is satisfied, it operates the display unit 15 in the gradation restriction mode.

[0034] The first display gradation in the normal mode is 256 gradations from the minimum gradation "0" to the maximum gradation "255". In this embodiment, the minimum gradation corresponds to a state where no voltage is applied to the liquid crystal layer 1522, and corresponds to the display with the lowest brightness. The maximum gradation corresponds to a state where a voltage Vd is applied to the liquid crystal layer 1522, and corresponds to the display with the highest brightness. In the normal mode, the liquid crystal display panel 152 is driven and displayed based on image data having an 8-bit pixel value that can take 256 gradation levels. That is, a voltage is applied to the liquid crystal layer 1522 of each pixel so that the liquid crystal layer 1522 is in an orientation state where a transmitted light amount according to the pixel value (gradation value) is obtained. In the normal mode, 16.77 million colors can be displayed by combining 256 gradations of each color of RGB.

[0035] The second display gradation in the gradation restriction mode corresponds to the first display gradation minus the gradation range from the maximum gradation ("255") to the first gradation number, and the gradation range from the minimum gradation ("0") to the second gradation number in the first display gradation. Here, the first gradation number and the second gradation number are set to a value equal to or greater than 10% of the number of gradations (255) from the maximum gradation to the minimum gradation. From another perspective, the second display gradation corresponds to the number of display gradations reduced to 80% or less of the first display gradation. Specifically, in this embodiment, the first and second gradation numbers are both "26". Therefore, the second display gradation is 204 gradations from "26" to "229", excluding the gradation ranges of "0" to "25" and "230" to "255" from the first display gradation. In the gradation limit mode, if the gradation value (pixel value) of the image data is within the range of "0" to "25", the gradation value is converted to "26". Also, if the gradation value (pixel value) of the image data is within the range of "230" to "255", the gradation value is converted to "229". In the gradation limit mode, 8.48 million colors can be displayed by combining 204 gradations of each RGB color. From another perspective, the gradation limited mode is a display mode in which the maximum contrast is smaller than that of the normal mode, and the gradation limited mode is a display mode in which the range of chromaticity that can be displayed is smaller (the saturation is lower) than that of the normal mode.

[0036] In addition, the first number of gradations and the second number of gradations in the above do not necessarily have to be the same. For example, if pressure unevenness, which will be described later, is more likely to occur at the maximum gradation than at the minimum gradation, the first number of gradations may be made larger than the second number of gradations to enhance the effect of reducing pressure unevenness occurring in the maximum gradation area. Also, if pressure unevenness is more likely to occur at the minimum gradation than at the maximum gradation, the second number of gradations may be made larger than the first number of gradations to enhance the effect of reducing pressure unevenness occurring in the minimum gradation area.

[0037] FIG. 5 is a diagram showing gradation values ​​used to display the colors white, black, red, green, and blue in the normal mode and the gradation limit mode. In FIG. 5, a combination of the gradation values ​​of R, G, and B pixels used to display each color is represented as "(R gradation value, G gradation value, B gradation value)." To display white, the gradation values ​​(255, 255, 255) are used in the normal mode. On the other hand, in the gradation limit mode, the gradation values ​​are converted to (229, 229, 229), and the color is displayed slightly lower in brightness than in the normal mode and closer to gray. To display black, the gradation value (0, 0, 0) is used in normal mode. On the other hand, in limited gradation mode, the gradation value is converted to (26, 26, 26), and the color is displayed slightly brighter and grayer than in normal mode. When displaying red, the gradation value (255, 0, 0) is used in the normal mode. On the other hand, in the gradation limit mode, the gradation value is converted to (229, 26, 26), and the color is displayed slightly duller than in the normal mode. To display green, the gradation values ​​(0, 255, 0) are used in normal mode. On the other hand, in the gradation limit mode, the gradation values ​​are converted to (26, 229, 26), and the color is displayed slightly duller than in normal mode. To display blue, the gradation values ​​(0, 0, 255) are used in normal mode. On the other hand, in the gradation limit mode, the gradation values ​​are converted to (26, 26, 229), and the color is displayed slightly duller than in normal mode.

[0038] FIG. 6 is a diagram showing an example of a waveform pattern of the voltage applied to the liquid crystal layer 1522. In FIG. 6(a) to (e) show waveform patterns when displaying gray levels of "0", "26", "127", "229", and "255", respectively. The waveform patterns shown in Fig. 6 show the absolute value of the voltage applied to the liquid crystal layer 1522 at each point in time. Therefore, the transition of the potential for frame inversion (reversing the polarity of the applied voltage each time one frame is displayed) is not reflected in the diagram.

[0039] As shown in FIG. 6(a), when gray level "0" is to be displayed, the voltage applied to the liquid crystal layer 1522 is maintained at 0. Furthermore, as shown in FIG. 6(e), when displaying the gray scale "255", the voltage applied to the liquid crystal layer 1522 is maintained at the voltage Vd.

[0040] On the other hand, as shown in Fig. 6(b) to (d), when displaying halftones, a frame period in which the applied voltage is 0 (hereinafter referred to as a "voltage-off period") and a frame period in which a voltage Vd is applied (hereinafter referred to as a "voltage-on period") are mixed at a ratio according to the gradation value. That is, in this embodiment, halftones are expressed by frame rate control. Hereinafter, "length of voltage-on period / (length of voltage-on period+length of voltage-off period)" is referred to as "duty ratio". The length of one frame can be, for example, 1 / 60 seconds, but is not limited to this.

[0041] For example, as shown in Fig. 6(c), when displaying a grayscale "127" that is an intermediate grayscale between the maximum grayscale and the minimum grayscale, the voltage-on period and the voltage-off period are alternately switched every frame to set the duty ratio to 1 / 2. The switching cycle may be 2 frames or more. Also, as shown in FIG. 6(b), when displaying gray level "26", the duty ratio is lowered and the ratio of the voltage-on period is made smaller than that in FIG. 6(c). Also, as shown in FIG. 6(d), when displaying the gray scale "229", the duty ratio is increased and the ratio of the voltage-on period is made larger than that in FIG. 6(c). The duty ratio for each intermediate tone may simply be "tone value / 255", or may be further corrected so that the luminance difference between adjacent tone values ​​becomes uniform.

[0042] In this way, in halftone display, the voltage applied to the liquid crystal layer 1522 changes periodically between 0V and voltage Vd. Although the liquid crystal molecules respond to this voltage change (the alignment state changes), the period of change in the alignment state is extremely short, so that the display appears to be in the average alignment state in the repeating period of the waveform pattern. The alignment angle of the liquid crystal molecules in this average alignment state is an angle corresponding to the gradation value (an angle corresponding to the duty ratio). Therefore, the display appears to be in halftone with an amount of transmitted light corresponding to the gradation value. The amount of response of the liquid crystal molecules to the voltage change (amount of change in alignment state) depends on the response speed specific to the material of the liquid crystal layer 1522, the frame rate, etc.

[0043] (Handheld terminal operation) Next, the operation of the handy terminal 1 will be described, focusing on the transition of the display mode of the display unit 15.

[0044] The handheld terminal 1 of the present embodiment allows intuitive touch operation due to an integrated configuration of the touch panel 151 and the liquid crystal display panel 152. This configuration also allows the display unit 15 to be made thinner and ensures high visibility.

[0045] On the other hand, in this configuration, depending on the pressure of a finger or stylus on the touch panel 151, the touch panel 151 bends (deforms), and the pressure is also transmitted to the liquid crystal display panel 152. This is also the case when the touch panel 151 is pressed by a factor other than a touch operation. For example, when the handheld terminal 1 is dropped or subjected to an impact, the pressure may be transmitted to the liquid crystal display panel 152 via the touch panel 151. Since the handheld terminal 1 is usually a business terminal lent to an operator for business purposes, it is prone to being roughly handled, and thus it is easy for a situation in which pressure is applied to the liquid crystal display panel 152 as described above to occur.

[0046] When a pressure is transmitted to the liquid crystal display panel 152 and the glass substrate 1524 on the display surface side is partially bent, the thickness (cell thickness) of the liquid crystal layer 1522 in that portion changes, and the orientation of the liquid crystal molecules becomes disturbed. This disturbance in orientation leads to a change in the amount of transmitted light, and is visually recognized as pressure unevenness (pressure marks) on the display screen. Pressure unevenness appears, for example, as an area with lower brightness than the surroundings in a bright display such as white, and appears as an area with higher brightness than the surroundings in a dark display such as black.

[0047] This pressure unevenness is likely to occur particularly in a portion where the maximum gradation (gradation "255") or the minimum gradation (gradation "0") is displayed when the display unit 15 is operating in the first display mode. This is because when these gradations are displayed, the voltage applied to the liquid crystal layer 1522 does not change as shown in Figures 6(a) and 6(e), and the alignment state of the liquid crystal molecules is likely to remain disturbed.

[0048] Although such pressure unevenness is usually temporary and is caused by disturbance in the alignment of liquid crystal molecules, if pressure unevenness remains on the display screen, the user may mistakenly believe that the display unit is broken. Therefore, in the handheld terminal 1 of the present embodiment, in a situation where the pressure unevenness is likely to occur, the display mode of the display unit 15 is operated in the second display mode, thereby reducing the pressure unevenness to an unnoticeable level or eliminating it. Also, the occurrence of further pressure unevenness is suppressed.

[0049] The reason why the pressing unevenness can be reduced or eliminated by operating the display unit 15 in the second display mode is as follows. When switching from the first display mode to the second display mode, the maximum gradation (gradation "255") display switches to a half-tone display of gradation "229", and the minimum gradation (gradation "0") display switches to a half-tone display of gradation "26". At the time of this switching, the alignment state of the liquid crystal molecules changes according to the difference between the gradations before and after the switching. In other words, the liquid crystal molecules are rearranged to an appropriate alignment state corresponding to the half-tone after the switching (the alignment state is reset). This reduces or eliminates the alignment disturbance that occurred in the display area of ​​the maximum gradation or minimum gradation in the first display mode, and reduces or eliminates the pressure unevenness.

[0050] Furthermore, when the display unit 15 is operated in the second display mode, further pressure unevenness is less likely to occur. In the second display mode, as shown in Fig. 6(b) to (d), the applied voltage changes according to the grayscale value regardless of the grayscale level at which the display is performed, so that the liquid crystal molecules constantly move in response to this voltage change, and the alignment is less likely to be disturbed even if the cell thickness of the liquid crystal layer 1522 changes due to pressure.

[0051] In order for the liquid crystal molecules to be rearranged in an appropriate alignment state, it is desirable to cause a gradation change of 10% or more of the total number of gradations (255) from the maximum gradation or the minimum gradation. From another perspective, it is desirable to transition from the maximum gradation or the minimum gradation to an intermediate gradation with a duty ratio of 10% or more and 90% or less. For this reason, the second display gradation in the second operation mode is a gradation (gradation "26" to gradation "229") that excludes 10% or more above and below the first display gradation in the second operation mode.

[0052] Next, the above-mentioned display control processes involving switching of the display mode of the display unit 15 will be described using the first to fifth display control processes as examples. Two or more of the first to fifth display control processes may be combined. In any of the display control processes, the CPU 11 operates the display unit 15 in the second display mode when it is determined that a predetermined pressure unevenness suppression condition is satisfied.

[0053] <First display control process> FIG. 7 is a flowchart showing a control procedure by the CPU 11 of the first display control process. In the first display control process, a user who has logged in to the handheld terminal 1 is identified, and the display unit 15 is displayed in a display mode that is pre-associated with the user. The first display control process is started when the handheld terminal 1 is started up by a user operation (the same applies to the second to fifth display control processes described below).

[0054] When the first display control process is started, the CPU 11 causes the display unit 15 to perform display in the normal mode (step S101).

[0055] The CPU 11 determines whether or not the user has logged in (step S102). The login process is performed, for example, when a login request accompanied by input of a user ID and password is made from the user, and it is determined that the user ID and password are correct by referring to the user authentication data 143. The process of step S102 corresponds to a process of identifying the user who is operating the handy terminal 1 based on an input operation from the user.

[0056] If it is determined that a user has logged in ("YES" in step S102), CPU 11 refers to display mode setting data 142 and determines whether the display mode associated with the logged-in user is a gradation limiting mode (step S103).

[0057] FIG. 8 is a diagram showing an example of the contents of the display mode setting data 142. As shown in FIG. In the display mode setting data 142, a default display mode (normal mode or gradation limited mode) is set in association with a user ID unique to each user. The default display mode can be changed by the user performing a predetermined setting operation. The user sets the default display mode to the gradation limited mode when, for example, the user wants to prioritize the prevention of uneven pressing over contrast and display color.

[0058] When it is determined that the display mode associated with the user is the gradation limit mode ("YES" in step S103), the CPU 11 determines that the pressure unevenness suppression condition is satisfied, and causes the display unit 15 to perform display in the gradation limit mode (step S104). That is, the display mode of the display unit 15 is switched from the normal mode to the gradation limit mode.

[0059] When step S104 is completed, or when it is determined in step S103 that the display mode associated with the user is not the gradation limit mode ("NO" in step S103), CPU 11 determines whether or not the user has logged out (step S105). When it is determined that the user has not logged out ("NO" in step S105), CPU 11 executes the process of step S105 again. When it is determined that the user has logged out ("YES" in step S105), CPU 11 returns the process to step S101 and switches the display mode of display unit 15 to the normal mode.

[0060] If it is determined in the process of step S102 that the user is not logged in ("NO" in step S102), the CPU 11 determines whether or not a predetermined power-off operation has been performed (step S106). If it is determined that the power-off operation has not been performed ("NO" in step S106), the CPU 11 returns the process to the step from which the process branched (here, step S102), and if it is determined that the power-off operation has been performed ("YES" in step S106), the CPU 11 ends the display control process and turns off the power of the handheld terminal 1. The determination process in step S106 may be performed at any timing among steps S101 to S105. In other words, when a power-off operation is performed, the display control process may be terminated regardless of the processing content at that time. Hereinafter, a series of processes related to power-off from step S106 onwards is referred to as a power-off sequence.

[0061] <Second display control process> FIG. 9 is a flowchart showing a control procedure by the CPU 11 of the second display control process. In order to reduce battery consumption, when a predetermined time has elapsed without a user operation (without input to the touch panel 151), the handheld terminal 1 transitions to a dimming mode and reduces the display brightness of the display unit 15. In the second display control process, the display mode of the display unit 15 transitions to a gradation limiting mode in conjunction with the transition to the dimming mode.

[0062] When the second display control process is started, the CPU 11 causes the display unit 15 to perform display in the normal mode (step S201).

[0063] The CPU 11 judges whether or not a state in which there is no user operation for a predetermined time continues (step S202). If it is judged that there is no user operation for the predetermined time ("YES" in step S202), it judges that the brightness reduction condition is satisfied, and transitions to the dimming mode (step S203). That is, the CPU 11 reduces the emission brightness of the backlight 153, and reduces the display brightness of the display unit 15 to be lower than when the brightness reduction condition is not satisfied. Furthermore, if it is judged that the brightness reduction condition is satisfied as described above, the CPU 11 judges that the pressure unevenness suppression condition is satisfied, and causes the display unit 15 to perform display in the gradation restriction mode (step S204). That is, the display mode of the display unit 15 is switched from the normal mode to the gradation restriction mode. As a result, if there is pressure unevenness on the display unit 15, the pressure unevenness is reduced or eliminated.

[0064] The CPU 11 determines whether or not a user operation has been detected (step S205), and if it is determined that a user operation has not been detected ("NO" in step S205), executes the process of step S205 again.

[0065] When it is determined that a user operation has been detected ("YES" in step S205), CPU 11 determines that the brightness reduction condition is no longer satisfied, cancels the dimming mode, and increases the display brightness to the original brightness (step S206). When it is determined that the brightness reduction condition is no longer satisfied, CPU 11 determines that the pressure unevenness suppression condition is no longer satisfied, returns the process to step S201, and switches the display mode of display unit 15 to the normal mode. Prior to this, pressure unevenness has been reduced or eliminated in step S204, so pressure unevenness is not visible even when switching to the normal mode in step S201.

[0066] In the process of step S202, if it is determined that the state without user operation has not continued for the predetermined time ("NO" in step S202), CPU 11 determines whether or not a predetermined power-off operation has been performed (step S207), and executes a power-off sequence similar to that of the first display control process. The power-off sequence may be executed when a power-off operation is performed at any timing in steps S201 to S206.

[0067] 9, an example has been described in which the brightness reduction condition is that there is no user operation for a predetermined time (no input to touch panel 151), but the brightness reduction condition is not limited to this. For example, when a predetermined input operation instructing a transition to the dimming mode is performed by the user, it may be determined that the brightness reduction state is satisfied and the mode may be transitioned to the dimming mode. In this case as well, the display mode of display unit 15 is transitioned to the gradation limit mode together with the transition to the dimming mode. Furthermore, the user's operation may include not only input to the touch panel 151 but also input to the operation keys 16 .

[0068] <Third display control process> FIG. 10 is a flowchart showing a control procedure by the CPU 11 of the third display control process. In the third display control process, when a drop of the handheld terminal 1 or an impact on the handheld terminal 1 is detected, the display mode of the display unit 15 transitions to the gradation restriction mode.

[0069] When the third display control process is started, the CPU 11 causes the display unit 15 to perform display in the normal mode (step S301).

[0070] The CPU 11 determines whether or not a drop of the handheld terminal 1 has been detected based on the acceleration detection result by the acceleration sensor 18 (step S302). If it is determined that a drop has been detected ("YES" in step S302), the CPU 11 further determines whether or not an impact of a predetermined intensity (an impact whose intensity is greater than a predetermined value) has been detected based on the acceleration detection result by the acceleration sensor 18 (step S303).

[0071] FIG. 11 is a diagram showing an example of a pattern when a drop is detected and a pattern when an impact is detected in the detection result of acceleration. The graph in Fig. 11 plots the detection results of acceleration against the time axis. Pattern P1 in Fig. 11 is an example of a pattern of acceleration when the handheld terminal 1 is falling. Pattern P2 is an example of a pattern of acceleration when an impact is applied to the handheld terminal 1. In step S302, the CPU 11 determines whether or not the detection results of acceleration include pattern P1 indicating a fall based on predetermined pattern definition information for when a fall occurs. In step S303, the CPU 11 determines whether or not the detection results of acceleration include pattern P2 indicating the application of an impact based on predetermined pattern definition information for when an impact is applied.

[0072] If it is determined in step S303 that an impact of a predetermined strength has been detected ("YES" in step S303), CPU 11 determines that the pressure unevenness suppression condition is satisfied, and causes display unit 15 to perform display in the gradation restriction mode (step S304). That is, the display mode of display unit 15 is switched from the normal mode to the gradation restriction mode. As a result, even if pressure unevenness occurs on display unit 15 due to the impact, the pressure unevenness is reduced or eliminated.

[0073] The CPU 11 determines whether or not a predetermined time has elapsed since the transition to the gradation limit mode (step S305), and if it is determined that the predetermined time has not elapsed ("NO" in step S305), executes the processing of step S305 again.

[0074] If it is determined that the predetermined time has elapsed ("YES" in step S305), CPU 11 determines that the pressure unevenness suppression condition is no longer satisfied, and returns the process to step S301 to switch the display mode of display unit 15 to the normal mode. Since pressure unevenness has been reduced or eliminated in step S304 prior to this, pressure unevenness is not visible even when switching to the normal mode in step S301.

[0075] If a drop is not detected in the process of step S302 ("NO" in step S302), or if an impact is not detected in the process of step S303 ("NO" in step S303), CPU 11 determines whether a predetermined power-off operation has been performed (step S306), and executes a power-off sequence similar to the first display control process. The power-off sequence may be executed when a power-off operation is performed at any timing in steps S301 to S305.

[0076] 10, if a fall is detected in step S302 and then an impact is detected in step S303, it is determined that a large impact accompanied by a fall has been applied, and the mode is switched to the gradation restriction mode. However, this is not limited to the above, and in cases where the strength of the impact can be identified from the acceleration detection result, the fall detection in step S302 may be omitted, and it may be determined whether or not the pressure unevenness suppression condition is satisfied based only on the impact detection result in step S303. Furthermore, when the handheld terminal 1 is dropped, there is a high probability that some kind of impact will be applied subsequently, so if a fall is detected, it may be determined that the pressure unevenness suppression condition is satisfied, and the mode may be switched to the gradation restriction mode. In this case, the impact detection in step S303 may be omitted.

[0077] <Fourth display control process> FIG. 12 is a flowchart showing a control procedure by the CPU 11 of the fourth display control process. In the fourth display control process, if the pressure applied to the liquid crystal display panel 152 exceeds the reference pressure, it is determined that the pressure unevenness suppression condition is satisfied, and the display mode of the display unit 15 transitions to the gradation restriction mode.

[0078] When the fourth display control process is started, the CPU 11 causes the display unit 15 to perform display in the normal mode (step S401).

[0079] Based on the pressure detection result by the pressure sensor 17, the CPU 11 determines whether or not a pressure exceeding a reference pressure has been detected on the liquid crystal display panel 152 (step S402). The reference pressure is set to, for example, the upper limit of a pressure range in which no pressure unevenness occurs, or a value obtained by subtracting a predetermined margin from the upper limit. If a pressure exceeding the reference pressure has been detected, the CPU 11 determines that the pressure unevenness suppression condition is satisfied.

[0080] If it is determined that the pressure has been detected ("YES" in step S402), CPU 11 causes display unit 15 to perform display in gradation restriction mode (step S404) after determining that the series of input operations on touch panel 151 has ended ("YES" in step S403). That is, the display mode of display unit 15 is switched from normal mode to gradation restriction mode. As a result, even if pressure unevenness has occurred on display unit 15 due to touch operations, the pressure unevenness is reduced or eliminated. The determination of the end of the input operation in step S403 is made based on, for example, whether or not a predetermined time has elapsed since the last touch operation. It should be noted that the mode may be switched to the gradation restriction mode when it is determined in step S402 that a pressure exceeding the reference pressure has been detected, without waiting for the end of the input operation on the touch panel 151.

[0081] The CPU 11 determines whether or not a predetermined time has elapsed since the transition to the gradation limit mode (step S405), and if it is determined that the predetermined time has not elapsed ("NO" in step S405), executes the processing of step S405 again.

[0082] If it is determined that the predetermined time has elapsed ("YES" in step S405), CPU 11 determines that the pressure unevenness suppression condition is no longer satisfied, and returns the process to step S401 to switch the display mode of display unit 15 to the normal mode. Since pressure unevenness has been reduced or eliminated in step S404 prior to this, pressure unevenness is not visible even when switching to the normal mode in step S401.

[0083] In the process of step S402, if it is determined that a pressure exceeding the reference pressure has not been detected ("NO" in step S402), CPU 11 determines whether a predetermined power-off operation has been performed (step S406), and executes a power-off sequence similar to that of the first display control process. The power-off sequence may be executed when a power-off operation is performed at any timing in steps S401 to S405.

[0084] <Fifth display control process> FIG. 13 is a flowchart showing a control procedure by the CPU 11 of the fifth display control process. In the fifth display control process, after display starts in the normal mode, when a first waiting time has elapsed, the mode transitions to the gradation limit mode, and after display starts in the gradation limit mode, when a second waiting time has elapsed, the mode transitions to the normal mode.

[0085] When the fifth display control process is started, the CPU 11 causes the display unit 15 to perform display in the normal mode (step S501).

[0086] After starting display in the normal mode, the CPU 11 determines whether or not a first waiting time has elapsed (step S502). If it is determined that the first waiting time has elapsed ("YES" in step S502), the CPU 11 determines that the pressure unevenness suppression condition is satisfied, and causes the display unit 15 to perform display in the gradation restriction mode (step S503). That is, the display mode of the display unit 15 is switched from the normal mode to the gradation restriction mode. As a result, if pressure unevenness occurs on the display unit 15, the pressure unevenness is reduced or eliminated.

[0087] The CPU 11 determines whether the second waiting time has elapsed after the transition to the gradation limit mode (step S504), and if it is determined that the second waiting time has not elapsed ("NO" in step S504), executes the processing of step S504 again.

[0088] If it is determined that the second waiting time has elapsed ("YES" in step S504), CPU 11 determines that the pressure unevenness suppression condition is no longer satisfied, and returns the process to step S501 to switch the display mode of display unit 15 to the normal mode. Since pressure unevenness has been reduced or eliminated in step S503 prior to this, pressure unevenness is not visible even when switching to the normal mode in step S501.

[0089] In the process of step S502, if it is determined that the first waiting time has not elapsed ("NO" in step S502), CPU 11 determines whether or not a predetermined power-off operation has been performed (step S505), and executes a power-off sequence similar to the first display control process. The power-off sequence may be executed when a power-off operation is performed at any timing in steps S501 to S504.

[0090] The lengths of the first and second standby times are not particularly limited, but may be, for example, 1 minute. The first and second standby times may be set as fixed values ​​at the time of shipment, or may be set by the user to desired values.

[0091] (effect) As described above, the handy terminal 1 as a terminal device according to this embodiment includes the display unit 15 having the liquid crystal display panel 152 provided with the touch panel 151, and the CPU 11, which controls the display operation of the display unit 15 (control means). The CPU 11 can operate the display unit 15 in a normal mode (first display mode) in which a display is performed in a first display gradation, and in a gradation limited mode (second display mode) in which a display is performed in a second display gradation having fewer gradations than the first display gradation, and operates the display unit 15 in the second display mode when it is determined that a predetermined pressure unevenness suppression condition is satisfied (control means). By switching from the first display mode to the second display mode, which has a relatively smaller number of displayed gradations, a transition occurs in the displayed gradations, and the liquid crystal molecules are rearranged to the appropriate alignment state along with this transition. This makes it possible to reduce or eliminate pressure unevenness caused by the disturbance of the alignment. Therefore, it is possible to suppress the remaining pressure unevenness with simple control. Furthermore, the change in the display screen when switching from the first display mode to the second display mode is merely a slight decrease in contrast and saturation, so that pressure unevenness can be reduced or eliminated in an unnoticeable manner.

[0092] The second display gradation is obtained by excluding from the first display gradation the gradation range from the maximum gradation to the first number of gradations and the gradation range from the minimum gradation to the second number of gradations in the first display gradation. According to this, when switching from the first display mode to the second display mode, the region that was displaying the maximum or minimum grayscale can be caused to transition to an intermediate grayscale, and the liquid crystal molecules can be rearranged in an appropriate alignment state. Therefore, the pressure unevenness that tends to occur in the display region of the maximum or minimum grayscale can be efficiently reduced or eliminated. Moreover, each gray scale in the second display mode corresponds to one of the intermediate gray scales in the first display mode. In these intermediate gray scales, the voltage applied to the liquid crystal layer 1522 repeatedly changes according to the gray scale value, so that the liquid crystal molecules constantly move in response to the voltage change, and the alignment of the liquid crystal molecules is less likely to be disturbed. Therefore, by performing display in the second display mode, it is possible to suppress the occurrence of pressure unevenness compared to when displaying in the first display mode.

[0093] Moreover, the first number of gradations and the second number of gradations are 10% or more of the number of gradations from the maximum gradation to the minimum gradation. This allows a change in gradation of 10% or more to occur in the area where the maximum or minimum gradation was displayed when switching from the first display mode to the second display mode, and therefore the alignment state of the liquid crystal molecules in the area can be sufficiently changed, so that the pressing unevenness can be more effectively reduced or eliminated.

[0094] In the first display control process, the CPU 11 identifies a user who is operating the handheld terminal 1 (own device) based on an input operation from the user (user identification means). The CPU 11 also determines that the pressure unevenness suppression condition is satisfied when the display mode associated with the identified user is the second display mode in the display mode setting data 142 in which the display mode of the display unit 15 is associated and set for each user (control means). This allows display to be performed in the second display mode in which pressing unevenness is less likely to occur, according to the user's desire.

[0095] In addition, in the second display control process, when a predetermined brightness reduction condition is satisfied, the CPU 11 reduces the display brightness of the display unit 15 more than when the brightness reduction condition is not satisfied, and determines that the pressure unevenness suppression condition is satisfied when the brightness reduction condition is satisfied (control means). The dimming mode that reduces the display brightness is applied when, for example, no operation is performed for a predetermined period of time, and therefore, in the dimming mode, the user does not usually look at the display screen. Therefore, according to the above configuration in which the display mode is switched to the second display mode upon transition to the dimming mode, the reduction in contrast and saturation at the time of switching can be made less noticeable to the user.

[0096] Furthermore, in the second display control process, the CPU 11 determines that the luminance reduction condition is satisfied when there is no input to the touch panel 151 for a predetermined period of time (control means). This allows the display mode to be switched to the second display mode at a timing when the user is likely not looking at the display screen, making it possible to make the reduction in contrast and saturation during the switching less noticeable to the user.

[0097] Furthermore, the handheld terminal 1 includes an acceleration sensor 18. In the third display control process, the CPU 11 detects at least one of a drop of the handheld terminal 1 and a predetermined strength of an impact on the handheld terminal 1 based on the acceleration detection result by the acceleration sensor 18 (detection means). Furthermore, when at least one of a drop and an impact is detected, the CPU 11 determines that the pressure unevenness suppression condition is satisfied (control means). With this, even if the liquid crystal display panel 152 is pressed due to a drop and / or impact, causing pressure unevenness, the pressure unevenness can be reduced or eliminated in a timely manner by switching to the second display mode.

[0098] The handheld terminal 1 also includes a pressure sensor 17 that detects the pressure applied to the liquid crystal display panel 152. In the fourth display control process, the CPU 11 determines that the pressure unevenness suppression condition is satisfied when the pressure detected by the pressure sensor 17 exceeds a predetermined reference pressure (control means). According to this, when the liquid crystal display panel 152 is pressed and a situation occurs in which pressure unevenness is likely to occur, the pressure unevenness can be reduced or eliminated by switching to the second display mode at an appropriate time.

[0099] Furthermore, in the fifth display control process, the CPU 11 determines that the pressure unevenness suppression condition is satisfied when a predetermined waiting time has elapsed after the start of display in the first display mode (control means). This makes it possible to reduce or eliminate the unevenness in pressure periodically with a simple process, and therefore to more reliably suppress the remaining unevenness in pressure.

[0100] Moreover, the program 141 according to this embodiment causes the CPU 11, which is a computer provided in the handheld terminal 1, to function as a control means for controlling the display operation of the display unit 15. The control means is capable of operating the display unit 15 in a normal mode (first display mode) in which a display is performed in a first display gradation, and a gradation restriction mode (second display mode) in which a display is performed in a second display gradation having fewer gradations than the first display gradation, and operates the display unit 15 in the second display mode when it is determined that a predetermined pressure unevenness suppression condition is satisfied. By operating the handheld terminal 1 according to such a program 141, it is possible to suppress residual pressure unevenness with simple control.

[0101] In the above description, an example has been disclosed in which an SSD (flash memory) of the storage unit 14 is used as a computer-readable medium for the program according to the present invention, but the present invention is not limited to this example. As other computer-readable media, information recording media such as HDD (Hard Disk Drive) and CD-ROM can be applied. In addition, a carrier wave is also applied to the present invention as a medium for providing data of the program according to the present invention via a communication line.

[0102] (others) The above description of the embodiment is merely an example of the terminal device and the program according to the present invention, and the present invention is not limited to this. For example, in the above embodiment, an example has been described in which touch panel 151 is stacked on top of liquid crystal display panel 152, but touch panel 151 may be provided in association with liquid crystal display panel 152, for example, may be built into liquid crystal display panel 152.

[0103] In addition, in the above embodiment, 204 gradations from "26 to 229" are exemplified as the second display gradation in the second display mode, but the present invention is not limited to this.

[0104] Furthermore, the liquid crystal display panel 152 is not limited to one capable of color display, and may be one capable of monochrome display.

[0105] Furthermore, the liquid crystal display panel 152 is not limited to a transmissive type, but may be a reflective type that displays images by reflecting incident light from the display surface side with an internal reflective film.

[0106] In the above embodiment, the handheld terminal 1 is exemplified as the terminal device, but the present invention is not limited to this. The terminal device may be any device having a liquid crystal display panel with a touch panel, such as a smartphone, a tablet terminal, a portable game machine, or a notebook PC.

[0107] Furthermore, the detailed configuration and detailed operation of each component of the handy terminal 1 as the terminal device in the above embodiment can of course be modified as appropriate without departing from the spirit of the present invention.

[0108] Although the embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, but includes the scope of the invention described in the claims and its equivalents. The inventions described in the claims originally attached to this application are set forth below. The claim numbers in the appended claims are the same as those in the claims originally attached to this application. [Additional Notes] <Claim 1> A display unit having a liquid crystal display panel provided with a touch panel; A control means for controlling a display operation of the display unit; Equipped with The control means The display unit can be operated in a first display mode in which a display is performed at a first display gradation, and in a second display mode in which a display is performed at a second display gradation having a smaller number of gradations than the first display gradation, The terminal device is characterized in that, when it is determined that a predetermined pressure unevenness suppression condition is satisfied, the display unit is operated in the second display mode. <Claim 2> The terminal device according to claim 1, characterized in that the second display gradation is obtained by excluding from the first display gradation a gradation range from a maximum gradation to a first number of gradations and a gradation range from a minimum gradation to a second number of gradations in the first display gradation. <Claim 3> 3. The terminal device according to claim 2, wherein the first number of gradations and the second number of gradations are equal to or greater than 10% of the number of gradations from the maximum gradation to the minimum gradation. <Claim 4> a user identification means for identifying a user who is operating the device based on an input operation from the user; The terminal device according to any one of claims 1 to 3, characterized in that the control means determines that the pressure unevenness suppression condition is satisfied when the display mode associated with the user identified by the user identification means is the second display mode in display mode setting information in which the display mode of the display unit is associated with each user. <Claim 5> The control means When a predetermined luminance reduction condition is satisfied, the display luminance of the display unit is reduced more than when the luminance reduction condition is not satisfied; 5. The terminal device according to claim 1, wherein the pressure unevenness suppression condition is determined to be satisfied when the luminance reduction condition is satisfied. <Claim 6> 6. The terminal device according to claim 5, wherein the control means determines that the luminance reduction condition is satisfied when there is no input to the touch panel for a predetermined period of time. <Claim 7> An acceleration sensor; a detection means for detecting at least one of a drop of the device and a shock of a predetermined intensity applied to the device based on a detection result of the acceleration by the acceleration sensor; Equipped with 7. The terminal device according to claim 1, wherein the control means determines that the pressure unevenness suppression condition is satisfied when the detection means detects at least one of the drop and the impact. <Claim 8> a pressure sensor for detecting a pressure applied to the liquid crystal display panel; 8. The terminal device according to claim 1, wherein the control means determines that the pressure unevenness suppression condition is satisfied when the pressure detected by the pressure sensor exceeds a predetermined reference pressure. <Claim 9> The terminal device according to any one of claims 1 to 8, characterized in that the control means determines that the pressure unevenness suppression condition is satisfied when a predetermined waiting time has elapsed after display in the first display mode has started. <Claim 10> a computer provided in a terminal device including a display unit having a liquid crystal display panel provided with a touch panel is caused to function as a control means for controlling a display operation of the display unit; The control means The display unit can be operated in a first display mode in which a display is performed at a first display gradation, and in a second display mode in which a display is performed at a second display gradation having a smaller number of gradations than the first display gradation, A program that causes the display unit to operate in the second display mode when it is determined that a predetermined pressure unevenness suppression condition is satisfied. [Explanation of symbols]

[0109] 1. Handheld terminal 11 CPU (control means, user identification means, detection means) 12 RAM 13 ROM 14 Storage section 141 Programs 142 Display mode setting data 143 User authentication data 15 Display 151 Touch Panel 152 Liquid crystal display panel 1521, 1524 Glass substrate 1522 Liquid crystal layer 1523 Spacer 153 Backlight 16 Operation keys 17 Pressure Sensor 18 Acceleration Sensor 19. Barcode Scanner 20 Communications Department 21 Bus

Claims

1. A display unit having a liquid crystal display panel provided with a touch panel; A control means for controlling a display operation of the liquid crystal display panel; An acceleration sensor; a detection means for detecting at least one of a drop of the device and a shock of a predetermined intensity applied to the device based on a detection result of the acceleration by the acceleration sensor; Equipped with The control means The liquid crystal display panel can be operated in any one of a first display mode in which a display is performed at a first display gradation and a second display mode in which a display is performed at a second display gradation having a smaller number of gradations than the first display gradation, operating the liquid crystal display panel in the second display mode when it is determined that a pressure unevenness suppression condition related to pressure unevenness occurring in the liquid crystal display panel due to pressing of the touch panel is satisfied; the second display gradation is obtained by subtracting from the first display gradation a gradation range from a minimum gradation to a first gradation number in the first display gradation, The control means determines that the pressure unevenness suppression condition is satisfied when at least one of the drop and the impact is detected by the detection means. A terminal device comprising:

2. The terminal device according to claim 1, characterized in that the second display gradation is obtained by excluding from the first display gradation a gradation range from a minimum gradation to a first number of gradations and a gradation range from a maximum gradation to a second number of gradations in the first display gradation.

3. 3. The terminal device according to claim 2, wherein the first number of gradations and the second number of gradations are equal to or greater than 10% of the number of gradations from the maximum gradation to the minimum gradation.

4. a display unit having a liquid crystal display panel provided with a touch panel, an acceleration sensor, and detection means for detecting at least one of a drop of the device and an impact of a predetermined strength on the device based on a detection result of acceleration by the acceleration sensor, the computer provided in the terminal device being made to function as a control means for controlling a display operation of the liquid crystal display panel, The control means The liquid crystal display panel can be operated in any one of a first display mode in which a display is performed at a first display gradation and a second display mode in which a display is performed at a second display gradation having a smaller number of gradations than the first display gradation, operating the liquid crystal display panel in the second display mode when it is determined that a pressure unevenness suppression condition related to pressure unevenness occurring in the liquid crystal display panel due to pressing of the touch panel is satisfied; the second display gradation is obtained by subtracting from the first display gradation a gradation range from a minimum gradation to a first gradation number in the first display gradation, The control means determines that the pressure unevenness suppression condition is satisfied when at least one of the drop and the impact is detected by the detection means. A program characterized by:

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