JP7639370B2 - Terminal device and program - Google Patents

Description

The present invention relates to a terminal device and a program.

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 touch operations made with a finger, a stylus, or the like on the display screen of the liquid crystal display panel.

JP 2020-24654 A

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 alignment of the liquid crystal molecules, if pressure unevenness remains on the display screen, there is an issue that the user may mistakenly believe that this is a malfunction of the display unit.

The object of this invention is to provide a terminal device and a program that can suppress residual pressure unevenness.

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 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.
It is characterized by :

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 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 the detection means detects at least one of the drop and the impact.
It is characterized by:

The present invention makes it possible to prevent residual uneven pressure.

FIG. 1 is a diagram showing a handheld terminal as a terminal device. FIG. 2 is a block diagram showing a functional configuration of the handheld terminal. FIG. 2 is a schematic cross-sectional view showing a configuration of a display unit. 3A and 3B are diagrams illustrating display modes of a display unit. FIG. 11 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. 5A and 5B are diagrams illustrating examples of waveform patterns of voltages applied to a liquid crystal layer. 10 is a flowchart showing a control procedure of a first display control process. 13A and 13B are diagrams illustrating an example of the contents of display mode setting data. 10 is a flowchart showing a control procedure of a second display control process. 13 is a flowchart showing a control procedure of a third display control process. 11A and 11B are diagrams illustrating examples of patterns of acceleration detection results when a drop is detected and when an impact is detected. 13 is a flowchart showing a control procedure of a fourth display control process. 13 is a flowchart showing a control procedure of a fifth display control process.

The following describes an embodiment of the terminal device and program of the present invention with reference to the drawings.

(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 location where it is installed, and is operated by an operator such as a store clerk or manager at the location where it is installed. The handy terminal 1 includes a display unit 15 arranged on the front, various operation keys 16 arranged 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.

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 (Central Processing Unit) 11 (computer), a RAM (Random Access Memory) 12, a ROM (Read Only Memory) 13, 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. Each unit of the handy terminal 1 is connected to the bus 21. In addition to these components, the handy terminal 1 may include a camera for acquiring images and notification means such as a buzzer and an LED (Light Emitting Diode).

The CPU 11 is a processor that controls each part of the handheld terminal 1 by performing various processes according to the program 141 stored in the memory unit 14. By executing the program 141 and performing various processes, the CPU 11 functions 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 drops and impacts, and the like.

RAM 12 provides working memory space for CPU 11 and stores temporary data. RAM 12 may include non-volatile memory.

ROM 13 is a non-volatile memory unit from which information can be read, and stores various setting data, etc.

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 the user is associated with, for example, a user ID unique to the user.

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.

The operation keys 16 are pressed by the user. The operation keys 16 include character input keys for inputting numbers and letters, function keys for calling up and executing a specific function, and a trigger key for causing the barcode scanner 19 to start a reading operation. When an operation key 16 is pressed, an operation signal corresponding to the function of that operation key 16 is transmitted to the CPU 11 and accepted as an input operation.

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.

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 the dropping of the handheld terminal 1, an impact applied to the handheld terminal 1, etc.

The barcode scanner 19 reads symbols such as barcodes or two-dimensional codes generated according to predetermined rules, decodes the resulting signal, and outputs it to the CPU 11. At least a part of the decoding process may be executed by the CPU 11. The barcode scanner 19 emits laser light from a reading surface provided on the back of the handheld terminal 1, and reads the symbol based on the intensity distribution of the reflected light of the laser light on the surface to be read.

The communication unit 20 is a communication module having an antenna, a modulation/demodulation circuit, a signal processing circuit, etc., and performs communication control corresponding to the 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.

(Configuration and operation of display unit)
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.

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

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 towards the liquid crystal display panel 152, the light that passes 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, multiple LEDs and a light guide plate that guides the light emitted from these LEDs to the inside and reflects it towards the liquid crystal display panel 152. By increasing or decreasing the amount of current flowing through the LEDs, the emission brightness of the backlight 153 can be adjusted, and thus the display brightness of the display unit 15 can be adjusted. The emission brightness of the backlight 153 is controlled by the CPU 11.

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 at right angles to each other.

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 depending on 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 depending on 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 depending on the polarization state at the time of passage. More specifically, when no voltage is applied to the liquid crystal layer 1522, the polarization state (linear polarization) of the incident light in the liquid crystal layer 1522 hardly changes, 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 transitions to linearly polarized light perpendicular to the polarized light or elliptically polarized light, and a part of the light emitted from the liquid crystal layer 1522 passes through the polarizer on the display surface side. In addition, by adjusting the applied voltage signal to set the orientation state of the liquid crystal layer 1522 to an intermediate state between the state where no voltage is applied and the state where the voltage Vd is applied, it is possible to perform halftone display with the amount of transmitted light from the polarizer on the display surface side as an intermediate value. In addition, 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, it is possible to adjust the amount of transmitted light from each pixel. By adjusting the amount of transmitted light from each pixel arranged in a matrix, it is possible to perform a desired display on the liquid crystal display panel 152.

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

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.

The electrode configuration and driving method in the liquid crystal display panel 152 are not particularly limited, but can 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.

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 the switching elements of each pixel on and off in response to a control signal sent from the CPU 11 to perform display on the liquid crystal display panel 152.

The alignment method of the liquid crystal layer 1522 can be, for example, a twisted nematic (TN) method. However, this 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.

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 of a normal mode (first display mode) in which each pixel performs display in a first display gradation, and a gradation limit mode (second display mode) in which each pixel performs display in a second display gradation having fewer gradations than the first display gradation, as specified by the CPU 11. In other words, the CPU 11 can operate the display unit 15 in any one of the normal mode and the gradation limit mode, and can switch to the other display mode at any timing. In addition, when the CPU 11 determines that a predetermined pressure unevenness suppression condition is satisfied, it operates the display unit 15 in the gradation limit mode.

The first display gradation in the normal mode is 256 gradations ranging 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 8-bit pixel values that can take 256 gradation levels. That is, a voltage is applied to the liquid crystal layer 1522 of each pixel so that the orientation state is such that the amount of transmitted light 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.

The second display gradation in the gradation limiting mode corresponds to the gradation range of the first display gradation from the maximum gradation ("255") to the first gradation number, and the gradation range of the first display gradation from the minimum gradation ("0") to the second gradation number, subtracted from 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 of the RGB colors.
From another perspective, the gradation limited mode is a display mode in which the maximum contrast is smaller than that in 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 in the normal mode.

The first number of gradations and the second number of gradations do not necessarily have to be the same. For example, if the pressure unevenness described below 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 the pressure unevenness is more likely to occur at the minimum gradation than 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.

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 grayscale values (255, 255, 255) are used in the normal mode. On the other hand, in the grayscale limit mode, the grayscale values are converted to (229, 229, 229), and the color is displayed with a slightly lower brightness than in the normal mode and closer to gray.
To display black, the normal mode uses gradation values of (0, 0, 0). On the other hand, in the gradation limited mode, the gradation values are converted to (26, 26, 26), and a color that is slightly brighter and closer to gray than the normal mode is displayed.
When displaying red, the gradation values (255, 0, 0) are used in the normal mode, whereas in the gradation limited mode, the gradation values are converted to (229, 26, 26), and the color is displayed as slightly duller than in the normal mode.
To display green, the normal mode uses gradation values of (0, 255, 0). On the other hand, in the gradation limited mode, the gradation values are converted to (26, 229, 26), and the color is displayed as slightly duller than in the normal mode.
When displaying blue, the gradation values (0, 0, 255) are used in the normal mode, whereas in the gradation limit mode, the gradation values are converted to (26, 26, 229), resulting in a color that is slightly duller than in the normal mode.

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 for 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.

As shown in FIG. 6A, 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 a gray scale "255", the voltage applied to the liquid crystal layer 1522 is maintained at the voltage Vd.

On the other hand, as shown in Figures 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 in 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.

For example, as shown in Fig. 6C, when displaying a gradation "127" that is an intermediate level between the maximum gradation and the minimum gradation, the voltage-on period and the voltage-off period are alternately switched every frame to set the duty ratio to 1/2. Note that the switching period may be two frames or more.
Also, as shown in FIG. 6B, 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. 6C.
Also, as shown in FIG. 6D, when displaying the gray level "229", the duty ratio is increased and the ratio of the voltage-on period is made larger than that in FIG. 6C.
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.

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 alignment state changes over an extremely short period of time, so the display appears to be in the average alignment state over the repetition period of the waveform pattern. The alignment angle of the liquid crystal molecules in this average alignment state is an angle that corresponds to the gradation value (an angle that corresponds to the duty ratio). Therefore, halftone display appears to be performed with an amount of transmitted light that corresponds 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.

(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.

The handheld terminal 1 of this embodiment has an integrated configuration of the touch panel 151 and the liquid crystal display panel 152, allowing intuitive touch operation. This configuration also allows the display unit 15 to be made thinner while ensuring high visibility.

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 will bend (deform), and the pressure will be transmitted to the liquid crystal display panel 152. This is also true when the touch panel 151 is pressed by factors other than a touch operation. For example, if 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 situations in which pressure is applied to the liquid crystal display panel 152 like this can easily occur.

When 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 a lower brightness than the surrounding area in a bright display such as white, and as an area with a higher brightness than the surrounding area in a dark display such as black.

This pressure unevenness is particularly likely to occur in areas where the maximum gradation (gradation "255") or 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 (e), and the alignment state of the liquid crystal molecules tends to remain disordered.

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 uneven pressure is likely to occur, the display mode of the display unit 15 is operated in the second display mode, thereby reducing the uneven pressure to an unnoticeable level or eliminating the uneven pressure. Also, the occurrence of further uneven pressure is suppressed.

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 is switched to a halftone display of gradation "229", and the minimum gradation (gradation "0") display is switched to a halftone 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 halftone after the switching (the alignment state is reset). This reduces or eliminates the alignment disorder that occurred in the display area of the maximum gradation or the minimum gradation in the first display mode, and reduces or eliminates the pressure unevenness.

In addition, 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 Figures 6(b) to (d), the applied voltage changes according to the grayscale value regardless of the grayscale level displayed, so 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.

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) relative to the maximum or minimum gradation. From another perspective, it is desirable to transition from the maximum or 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 operating mode is the first display gradation in the second operating mode minus 10% or more above and below (gradation "26" to gradation "229").

Next, the display control processes involving switching the display mode of the display unit 15 described above 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 determines that a predetermined pressure unevenness suppression condition is satisfied.

<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).

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

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 by the user, and the user ID and password are determined to be correct by referring to the user authentication data 143. The process of step S102 corresponds to a process of identifying the user operating the handheld terminal 1 based on the input operation by the user.

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

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, he/she wants to prioritize the prevention of uneven pressing over contrast and display color.

If 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). In other words, the display mode of the display unit 15 is switched from the normal mode to the gradation limit mode.

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), the 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), the CPU 11 executes the process of step S105 again. When it is determined that the user has logged out ("YES" in step S105), the CPU 11 returns the process to step S101 and switches the display mode of the display unit 15 to the normal mode.

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 display control process is ended and the power to the handheld terminal 1 is turned off.
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.

<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 any user operation (no 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 when the handheld terminal 1 transitions to the dimming mode.

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

The CPU 11 determines whether or not a state in which there has been no user operation for a predetermined time (step S202). If it is determined that there has been no user operation for the predetermined time ("YES" in step S202), it determines that the brightness reduction condition is satisfied and transitions to dimming mode (step S203). That is, the CPU 11 reduces the emission brightness of the backlight 153 to reduce the display brightness of the display unit 15 compared to when the brightness reduction condition is not satisfied. In addition, if it is determined that the brightness reduction condition is satisfied as described above, 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 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.

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 (step S205: NO), it executes the process of step S205 again.

If it is determined that a user operation has been detected ("YES" in step S205), the 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). If it is determined that the brightness reduction condition is no longer satisfied, the 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 the display unit 15 to the normal mode. Prior to this, the pressure unevenness was reduced or eliminated in step S204, so that the pressure unevenness is not visible even when the display mode is switched to the normal mode in step S201.

If it is determined in the process of step S202 that the state in which there is no user operation has not continued for the predetermined time ("NO" in step S202), the CPU 11 determines whether or not a predetermined power-off operation has been performed (step S207) 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 S201 to S206.

9, an example has been described in which the brightness reduction condition is the absence of a user operation for a predetermined period of time (the absence of input to the 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 transition to the dimming mode may be made. In this case as well, the display mode of the display unit 15 is transitioned to the gradation limiting 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 .

<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 is switched to the gradation restriction mode.

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

Based on the acceleration detection result by the acceleration sensor 18, the CPU 11 determines whether or not a drop of the handheld terminal 1 has been detected (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).

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.

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

The CPU 11 determines whether a predetermined time has elapsed since the transition to the gradation limit mode (step S305), and if it determines that the predetermined time has not elapsed (step S305: NO), it executes the processing of step S305 again.

If it is determined that the predetermined time has elapsed ("YES" in step S305), the 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 the display unit 15 to the normal mode. Prior to this, pressure unevenness was reduced or eliminated in step S304, so pressure unevenness is not visible even when switching to the normal mode in step S301.

If a fall 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), the 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.

In FIG. 10, if a fall is detected in step S302 and then an impact is detected in step S303, it is assumed 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 determined from the acceleration detection results, the fall detection in step S302 may be omitted, and it may be determined whether the pressure unevenness suppression condition is met based only on the result of the impact detection in step S303. Also, when the handheld terminal 1 is dropped, there is a high probability that some kind of impact will subsequently be applied, so if a fall is detected, it may be determined that the pressure unevenness suppression condition is met, and the mode may be switched to the gradation restriction mode. In this case, the impact detection in step S303 may be omitted.

<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 limiting mode.

When the fourth display control process starts, the CPU 11 causes the display unit 15 to display in normal mode (step S401).

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

When it is determined that the pressure has been detected ("YES" in step S402), the CPU 11 determines that the series of input operations on the touch panel 151 has ended ("YES" in step S403), and then causes the display unit 15 to perform display in the gradation restriction mode (step S404). That is, the display mode of the display unit 15 is switched from the normal mode to the gradation restriction mode. As a result, even if pressure unevenness has occurred on the display unit 15 due to the touch operation, 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.

The CPU 11 determines whether a predetermined time has elapsed since the transition to the gradation limit mode (step S405), and if it determines that the predetermined time has not elapsed (step S405: NO), it executes the process of step S405 again.

If it is determined that the predetermined time has elapsed ("YES" in step S405), the 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 the display unit 15 to the normal mode. Prior to this, pressure unevenness was reduced or eliminated in step S404, so pressure unevenness is not visible even when switching to the normal mode in step S401.

If it is determined in the process of step S402 that a pressure exceeding the reference pressure has not been detected ("NO" in step S402), the CPU 11 determines whether a predetermined power-off operation has been performed (step S406) 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 S401 to S405.

<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 is switched to the gradation limit mode, and after display starts in the gradation limit mode, when a second waiting time has elapsed, the mode is switched to the normal mode.

When the fifth display control process starts, the CPU 11 causes the display unit 15 to display in normal mode (step S501).

After starting display in normal mode, the CPU 11 determines whether 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.

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), it executes the processing of step S504 again.

If it is determined that the second waiting time has elapsed ("YES" in step S504), the 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 the display unit 15 to the normal mode. Prior to this, pressure unevenness was reduced or eliminated in step S503, so pressure unevenness is not visible even when switching to the normal mode in step S501.

If it is determined in the process of step S502 that the first waiting time has not elapsed ("NO" in step S502), the 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.

The length of the first standby time and the second standby time is not particularly limited, but may be, for example, one minute. The first standby time and the second standby time may be set as fixed values at the time of shipment, or may be set by the user to a desired value.

(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 first display gradation is displayed, and in a gradation restriction mode (second display mode) in which 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 display gradations, a transition occurs in the displayed gradation, and the liquid crystal molecules are rearranged to an appropriate alignment state along with this transition. This makes it possible to reduce or eliminate pressure unevenness caused by disturbance in 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.

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 has been 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, thereby efficiently reducing or eliminating the pressure unevenness that tends to occur in the display region of the maximum or minimum grayscale.
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, the occurrence of pressure unevenness can be suppressed compared to when displaying in the first display mode.

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.

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 makes it possible to perform display in the second display mode, in which pressing unevenness is less likely to occur, in response to a user's request.

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, for example, when no operation is performed for a predetermined period of time, and therefore the user does not usually look at the display screen in the dimming mode. 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.

Furthermore, in the second display control process, the CPU 11 determines that the brightness reduction condition is satisfied when there is no input to the touch panel 151 for a predetermined 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.

The handheld terminal 1 also 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). 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).
According to this, even if the liquid crystal display panel 152 is pressed due to a fall 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.

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, it is possible to reduce or eliminate the pressure unevenness by switching to the second display mode at an appropriate time.

In addition, 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 uneven pressure periodically with a simple process, and therefore to more reliably suppress the remaining uneven pressure.

Moreover, the program 141 according to the present 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, residual pressure unevenness can be suppressed with simple control.

In the above explanation, 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 this is not limiting. As other computer-readable media, information recording media such as a hard disk drive (HDD) or a CD-ROM can be applied. In addition, a carrier wave can also be applied to the present invention as a medium for providing data for the program according to the present invention via a communication line.

(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 was described in which the touch panel 151 is stacked on top of the liquid crystal display panel 152, but the touch panel 151 may be provided in conjunction with the liquid crystal display panel 152, for example, it may be built into the liquid crystal display panel 152.

In addition, in the above embodiment, 204 gradations from "26 to 229" are given as an example of the second display gradation in the second display mode, but this is not limited to this.

In addition, the liquid crystal display panel 152 is not limited to being capable of color display, but may be capable of monochrome display.

In addition, 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.

In addition, in the above embodiment, a handheld terminal 1 is used as an example of a terminal device, but this 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.

Furthermore, the detailed configuration and detailed operation of each component of the handheld 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.

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,
A terminal device, 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 set in correspondence 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 brightness reduction condition is satisfied.
<Claim 6>
6. The terminal device according to claim 5, wherein the control means determines that the brightness 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
The terminal device according to any one of claims 1 to 6, characterized in that the control means determines that the pressure unevenness suppression condition is satisfied when the detection means detects at least one of the fall and the impact.
<Claim 8>
a pressure sensor for detecting a pressure applied to the liquid crystal display panel;
The terminal device according to any one of claims 1 to 7, characterized in that 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 display unit configured to display an image on the display screen in response to a predetermined pressure unevenness suppression condition being satisfied;

1 Handheld terminal 11 CPU (control means, user identification means, detection means)
12 RAM
13 ROM
14 Storage unit 141 Program 142 Display mode setting data 143 User authentication data 15 Display unit 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 Communication unit 21 Bus

Claims (4)

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

Images