Display device

Abstract

To provide a display device capable of preventing dew condensation.SOLUTION: The display device includes a display unit, an internal temperature measurement unit, an environment temperature measurement unit, an acquisition unit configured to acquire a first brightness setting value that is a current brightness setting of the display unit, and a control unit configured to control the display unit based on a first internal temperature measured by the internal temperature measurement unit, a first environment temperature measured by the environment temperature measurement unit, and the first brightness setting value acquired by the acquisition unit. And a control unit that determines whether dew condensation occurs on the display unit, and when it is determined that dew condensation occurs, controls the display unit to perform display at a second luminance setting value that is a luminance setting value smaller than the first luminance setting value and is a luminance setting value at which dew condensation does not occur.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a technique for preventing condensation from occurring in a display device. [Background technology]

[0002] In recent years, the increasing brightness and resolution of LCD panels have led to an increase in the power consumption of LCD panels and backlights. Furthermore, due to the emphasis on the performance and cost of LCD panels, many LCD panels and touch panels have been purchased separately and used in combination. In this configuration, an air gap is often provided between the LCD panel and the touch panel to reduce assembly costs.

[0003] However, in a configuration where there is an air gap between the LCD panel and the touch panel, the increased power consumption of the LCD panel can cause a temperature difference between the LCD panel and the touch panel, which can lead to condensation on the glass behind the touch panel, making it difficult to see the LCD panel screen.

[0004] Patent document 1 describes a technology for supplying power to an input operation unit including a liquid crystal display device and a touch panel in an image forming device, even in a special pause state in which the image forming device is not in a normal operating state, in order to prevent condensation due to environmental changes when the image forming device is in a special pause state. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-186327 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional example of Patent Document 1, condensation is prevented in a special sleep state, that is, when the power is off, so condensation cannot be prevented when the power is on and the device is in normal use.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a display device that can prevent condensation even during normal use. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the display device of the present invention comprises: A display device having a display unit, characterized by comprising: an internal temperature measuring unit; an environmental temperature measuring unit; an acquisition means for acquiring a first brightness setting value which is the current brightness setting of the display unit; and a control unit for determining whether condensation will occur on the display unit based on the first internal temperature measured by the internal temperature measuring unit, the first environmental temperature measured by the environmental temperature measuring unit, and the first brightness setting value acquired by the acquisition means, and for controlling the display unit to display at a second brightness setting value which is a brightness setting value smaller than the first brightness setting value and at which condensation will not occur, if it is determined that condensation will occur. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a display device that can prevent condensation even during normal use. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a configuration diagram of a display device according to a first embodiment. [Figure 2] 1 is a system block diagram of a display device according to a first embodiment. [Figure 3] 4 is a flowchart showing a process in the display device according to the first embodiment. [Figure 4] FIG. 10 is a configuration diagram of a display device according to a second embodiment. [Figure 5] FIG. 10 is a block diagram of a display device system according to a second embodiment. [Figure 6] 10 is a flowchart showing a process in the display device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] First Embodiment The display device of the first embodiment uses the internal temperature and the external temperature to determine whether condensation will occur, and if condensation will occur, limits the brightness to prevent condensation.

[0012] The configuration of the display device in the first embodiment will be described below.

[0013] 1 is a configuration diagram of a display device 100. The display device 100 is a display that displays an image based on input image data (image signal) or internally stored image data.

[0014] FIG. 2 is a system block diagram of the display device 100.

[0015] The display device 100 comprises a touch panel unit 101 , a display unit 102 , a light emitting unit 103 , an input operation unit 104 , a control board unit 105 , an environmental temperature measuring unit 106 , an internal temperature measuring unit 107 , and an exterior unit 111 .

[0016] The touch panel unit 101 is an input device that is configured to be planar and overlaid on the upper surface of the display unit 102 (described later) in order to detect a touch operation on the display screen of the display unit 102, and that outputs coordinate information corresponding to the contact position (touch position). The coordinate information is output to the control unit 108. The control unit 108 executes processing corresponding to the coordinate information input from the touch panel unit, thereby executing processing according to the touch operation.

[0017] The display unit 102 is provided above the light-emitting unit 103 (described later), and is a functional unit that displays images according to video signals by modulating light emitted from the light-emitting unit 103 using a liquid crystal panel. Liquid crystal shutter elements, color filters, and the like (not shown) are arranged in a matrix on the display unit 102. The liquid crystal shutter elements form images on the liquid crystal panel by changing the transmittance of the corresponding elements according to the RGB values ​​of each pixel of the video data. The liquid crystal shutter elements have multiple pixels arranged horizontally and vertically. Each pixel is provided with R, G, and B pixels as sub-pixels. The color filters are components that separate the light emitted from the light-emitting unit 103 into three wavelength bands, R, G, and B, respectively. Images, GUI screens constituting a GUI (Graphical User Interface), and the like are displayed under the control of a control board unit 105 (described later).

[0018] The light-emitting unit 103 is a light-emitting device that irradiates light onto the back surface of the display unit 102. The light-emitting unit 103 has one or more light sources (light source unit or light source group). The light emitted from the light source is diffused in the planar direction by a diffuser (not shown), and illuminates the display unit 102 from behind as a light-emitting source with a predetermined light spread. Note that, although an LED (light-emitting diode) or the like can be used as the light-emitting element of the light source, the light-emitting element of the light source is not limited to an LED. For example, a laser element, an organic EL element, a cold cathode fluorescent lamp element, a plasma element, or the like may also be used as the light-emitting element. The light-emitting unit 103 is controlled by a light-emitting drive unit 110 (described later), and the brightness of the display unit 102 can be changed by switching the light emission brightness of the light source of the light-emitting unit 103.

[0019] The input operation unit 104 is an input device for accepting user operations, and is provided in or connected to the display device 100. The input operation unit 104 includes a character information input device such as a keyboard, a pointing device such as a mouse or a touch panel, a button, a dial, a joystick, etc., and is used by the user to make various settings. The touch panel unit 101 may be used as the input operation unit. In this embodiment, the user can change the display brightness setting of the display unit 102 on the menu screen by operating the input operation unit 104. Various setting values ​​(including brightness setting values, etc.) set by the input operation unit 104 are output to the control unit 108 and stored in the storage unit 109.

[0020] The environmental temperature measurement unit 106 directly measures the ambient temperature of the display device 100 or estimates it from the temperature of a measurable part. Parts that can be estimated include, for example, members adjacent to the liquid crystal display unit 102, optical sheets such as light sources and light-emitting unit diffusers, electrical boards, and electrical components. In this embodiment, the environmental temperature measurement unit 106 is disposed outside the exterior casing 111 and is not affected by the temperature inside the display device 100. A temperature sensor that detects the temperature, such as a thermistor, is used, which outputs the temperature as a detected temperature value. The measured temperature is output to the control unit 108, which will be described later.

[0021] The internal temperature measurement unit 107 is disposed between the touch panel unit 101 and the display unit 102, and measures the temperature inside the display device 100, near the display unit 102. A temperature sensor that detects the temperature, such as a thermistor, that outputs the temperature as a detected temperature value is used. The measured temperature is output to the control unit 108, which will be described later.

[0022] The control board unit 105 is a board on which a control circuit configured from a control unit 108, a storage unit 109, and a light emission drive unit 110 is mounted. Here, it is placed on the opposite side of the light emitting surface (upper side) of the light emitting unit 103, but it may be configured as a separate unit from the display unit 102 and the light emitting unit 103.

[0023] The control unit 108 controls the entire display device 100 and performs various calculations. It changes various settings in response to operations on the input operation unit 104, changes the display brightness of the display unit 102 based on the brightness setting value set by the user, and acquires temperatures measured by the environmental temperature measurement unit 106 and the internal temperature measurement unit 107. Using the brightness setting value selected by the user via the input operation unit 104, the environmental temperature measured by the environmental temperature measurement unit 106, and the internal temperature of the display device 100 measured by the internal temperature measurement unit 107, the control unit 108 estimates the maximum internal temperature rise from the current brightness setting value and the environmental temperature. At this time, the control unit 108 may calculate the remaining temperature rise from the current internal temperature and calculate the temperature gradient from the time required for the rise. The following describes the case where the temperature gradient is calculated. The possibility of condensation occurrence is determined by comparing the allowable temperature gradient at each environmental temperature at which condensation does not occur, which is stored in the memory unit 109 (described later). Then, depending on the result of the condensation occurrence determination, it decides whether or not to change the brightness of the display unit 102 (the light-emitting brightness of the light-emitting unit 103). If it is determined that there is a possibility of condensation occurring, a luminance setting value that provides an allowable temperature gradient at which condensation will not occur is calculated, and the calculated luminance setting value is set in the light emission drive unit 110. At this time, the luminance setting value is set to the maximum luminance setting value at which condensation will not occur on the display unit 102 at the current ambient temperature. If it is determined that there is no possibility of condensation occurring, the current luminance setting value set by the user is sent to the light emission drive unit 110.

[0024] The storage unit 109 includes a ROM (Read Only Memory) and a RAM (Random Access Memory). The ROM, which is a non-volatile memory, stores the allowable temperature gradient at which condensation does not occur for each environmental temperature, and sends the allowable temperature gradient appropriate for the environmental temperature to the control unit 108 based on the environmental temperature information from the control unit 108. The relationship between the environmental temperature and the allowable temperature gradient is that when the environmental temperature is high, the amount of moisture in the air increases, causing thicker condensation. Therefore, even a gentle temperature gradient can easily cause thicker condensation that is detrimental to the user. The storage unit 109 also stores control programs that can be executed by the control unit 108. The RAM, which is a volatile memory, is used as a working memory.

[0025] The light-emitting drive unit 110 can adjust the light emission brightness of the light source of the light-emitting unit 103, and can change the brightness of the display unit 102 by driving the light source according to a brightness value set by the user via the input operation unit 104 or a brightness value calculated by the control unit 108. Here, the signal controlled by the light-emitting drive unit 110 represents, for example, the pulse width of a pulse signal (current or voltage pulse signal) to be applied to the light source. In this case, the light-emitting drive unit 110 adjusts the control signal to adjust the light emission brightness of the light source (PWM control). Note that the control signal may be a signal that represents the peak value of the pulse signal to be applied to the light source (PAM control), or may be a signal that represents both the pulse width and peak value (PWM control).

[0026] The exterior part 111 supports the touch panel part 101, the display part 102, the light emitting part 103, the control board part 105, and the environmental temperature measuring part 106. The material is not important, but it is desirable that there are no gaps between the exterior part 111 and the touch panel part 101 or the display part 102 to prevent the intrusion of dust and the like. It is desirable that the material of the part supporting the environmental temperature measuring part 106 is a material that does not easily conduct heat.

[0027] FIG. 3 is a flowchart showing a method of determining whether there is a risk of condensation occurring based on a combination of environmental temperature, internal temperature, and brightness information, and suppressing the occurrence of condensation by limiting brightness, according to the first embodiment.

[0028] Each process in this flowchart is realized by the control unit 108 executing various arithmetic processes and controlling each unit of the display device 100 based on a control program read from the storage unit 109.

[0029] In step S101, when the display device 100 is turned on, the control unit 108 starts this process.

[0030] In step S102, the control unit 108 acquires the value of the current environmental temperature from the environmental temperature measurement unit 106, acquires the current internal temperature inside the display device 100 from the internal temperature measurement unit 107, and proceeds to step S103.

[0031] In step S103, the control unit 108 acquires the current brightness setting value set by the user via the input operation unit 104 from the storage unit 109, and the process proceeds to step S104.

[0032] In step S104, the control unit 108 calculates the maximum temperature at which the internal temperature becomes saturated from the current environmental temperature acquired in step S102 and the brightness setting value acquired in step S103, and then proceeds to step S105.

[0033] In step S105, the control unit 108 calculates the rising temperature, which is the temperature that will rise from the current internal temperature when the display unit 102 displays at the set brightness setting value, from the maximum temperature calculated in step S104 and the internal temperature acquired in step S102. The rising temperature is the difference between the maximum temperature and the internal temperature, so it is calculated as rising temperature = maximum temperature - internal temperature. Then, the temperature gradient is calculated from the rising temperature and the time it takes to rise. Because the temperature gradient depends on the temperature difference from the internal temperature to the maximum temperature, the calculated rising temperature may be used instead of the temperature gradient.

[0034] In step S106, the control unit 108 reads from the storage unit the allowable temperature gradient corresponding to the environmental temperature acquired in step S102. The allowable temperature gradient indicates the temperature rise per predetermined time, and indicates the temperature rise gradient at which condensation may occur if the temperature rises further within the predetermined time. Because the allowable temperature gradient differs depending on the environmental temperature, the allowable temperature gradient for each environmental temperature is stored in advance in the storage unit 109.

[0035] In step S107, the control unit 108 compares the allowable temperature gradient acquired in S106 with the temperature gradient calculated in S105. If it determines that the calculated temperature gradient is equal to or smaller than the allowable temperature gradient, it determines that there is no possibility of condensation occurring, and proceeds to step S109. If the calculated temperature gradient is greater than the allowable temperature gradient, it determines that there is a possibility of condensation occurring, and proceeds to step S108.

[0036] If it is determined in step S107 that there is a possibility of condensation occurring with the current brightness setting, then in step S108, the control unit 108 changes the brightness setting value to a smaller value. The control unit 108 calculates the brightness setting value that will be the same as the allowable temperature gradient calculated in S106 for the environmental temperature and internal temperature acquired in S102, and determines this as the brightness setting value to be changed. The determined brightness setting value is sent to the light emission drive unit 110 and set.

[0037] If it is determined in step S107 that there is no possibility of condensation occurring with the current brightness setting, the control unit 108 proceeds to S109 without changing the brightness setting value. Here, if a current brightness setting value has not been set in the light-emitting drive unit 110, the brightness setting value acquired in S103 is transmitted to the light-emitting drive unit 110 and set. Note that in the above description, the brightness setting value set by the input operation unit 104 is stored in the storage unit 109. However, the brightness setting value may be transmitted to and set in the light-emitting drive unit 110 in response to a setting by the input operation unit 104, and the currently set brightness setting value may be held in the light-emitting drive unit 110. In this case, in S103, the control unit 108 acquires the brightness setting value from the light-emitting drive unit 110.

[0038] In step S109, light emission drive unit 110 causes light emission unit 103 to emit light based on the brightness setting value set by control unit 108. If the brightness setting value has been changed in S108, light emission unit 103 is caused to emit light at the changed brightness setting value, and if S108 has not been executed, light emission unit 103 is caused to emit light without changing the brightness setting value. Then, the process proceeds to step S110.

[0039] In step S110, the control unit 108 determines whether the input operation unit 104 has been operated and the brightness setting has been changed. If the brightness setting has not been changed, the process proceeds to S111. If the brightness setting has been changed, the temperature gradient changes depending on the changed brightness setting, so the processes of S102 to S109 are executed again. As described above, in the display device of this embodiment, the processes of S102 to S109 for preventing condensation are executed when the power is turned on in S101 and when the brightness setting is changed in S110. When the brightness setting is changed and the processes of S102 to S109 are executed again, the current internal temperature, the current ambient temperature, and the changed current brightness setting are acquired in S102 to S103, and the process of S104 is executed based on this information. Furthermore, when S102 to S109 are executed again, a new allowable temperature gradient may be calculated for the allowable temperature gradient calculated in S106 from both the previous allowable temperature gradient and the allowable gradient corresponding to the ambient temperature and internal temperature when the brightness setting was changed. Furthermore, the temperature gradient calculated in S105 may be calculated anew from both the previously calculated temperature gradient and the temperature gradient corresponding to the environmental temperature and internal temperature when the brightness setting value was changed.

[0040] In step S111, the control unit 108 determines whether the power has been turned off, and if the power has not been turned off, the process returns to step S110. If the power has been turned off, the control unit 108 ends this process.

[0041] As described above, in the first embodiment, a display device equipped with an environmental temperature measurement unit and an internal temperature measurement unit determines whether condensation will occur based on the current temperature information and brightness information, as shown in Fig. 3, and if it will occur, limits the brightness. This prevents condensation and prevents a decrease in user visibility.

[0042] <Second embodiment> The display device according to the second embodiment will be described below. The second embodiment adds a process to the first embodiment in which, based on humidity information inside the display device 100, it is determined that condensation will not occur if the humidity is below a certain level, regardless of the temperature gradient.

[0043] The configuration of the display device of the second embodiment is almost the same as that of the first embodiment, so the same components are denoted by the same reference numerals and the description thereof will be omitted.

[0044] FIG. 4 is a configuration diagram of a display device 100, which is obtained by adding a humidity measuring unit 400 to the configuration diagram of the first embodiment shown in FIG.

[0045] A system block diagram of this embodiment is shown in Figure 5. In the second embodiment, a humidity measurement unit 400 is added to the configuration of the first embodiment, and processing is added that does not limit brightness regardless of the temperature gradient when the humidity measured by the humidity measurement unit 400 is equal to or lower than a predetermined humidity.

[0046] The humidity measuring unit 400 measures the humidity inside the display device 100 and sends the result to the control unit 108 .

[0047] In addition to the contents of the first embodiment, the storage unit 109 stores a humidity level at which condensation does not occur, which is a problem for the display device, and sends this to the control unit 108.

[0048] FIG. 6 is a flowchart showing a process for determining whether condensation will occur based on a combination of the ambient temperature, internal temperature, brightness information, and humidity in the second embodiment, and for limiting brightness to prevent condensation from occurring if it is determined that condensation will occur.

[0049] Each process in the flowchart will be described below. The process in this flowchart is realized by the control unit 108 executing various arithmetic processes and controlling each unit of the display device 100 based on a control program read from the storage unit 109.

[0050] Step S201 is the same process as step S101 in FIG. 2 described in the first embodiment, and therefore a description thereof will be omitted.

[0051] In step S202, the control unit 108 acquires the value of the current environmental temperature measured by the environmental temperature measurement unit 106, acquires the current temperature inside the display device 100 measured by the internal temperature measurement unit 107, and acquires the humidity inside the display device 100 measured by the humidity measurement unit 400.

[0052] Steps S203 to S205 are the same as steps S103 to S105 in FIG. 2 described in the first embodiment, and therefore a description thereof will be omitted.

[0053] In step S206, the control unit 108 calculates the allowable gradient in the same manner as in S 106. In step S206, the control unit 108 further acquires from the storage unit 109 humidity information at which condensation does not occur (for example, humidity of 60%).

[0054] In step S207, the control unit 108 determines whether the current humidity acquired in S202 is equal to or lower than the humidity (60%) at which condensation does not occur acquired in S206. If it is equal to or lower than the humidity at which condensation does not occur, the process proceeds to step S210, and if it is higher than the humidity at which condensation does not occur, the process proceeds to step S208.

[0055] Steps S208 to S212 are the same as steps S107 to S111 in FIG. 2 described in the first embodiment, and therefore a description thereof will be omitted.

[0056] In this way, the display device of the second embodiment determines whether condensation will occur based on the current temperature information, humidity information, and brightness information, as shown in Fig. 6. If it is determined that condensation will occur based on the condensation occurrence determination result, the brightness is limited, thereby preventing condensation during normal use and preventing a decrease in user visibility without providing a special state when the power is turned off.

[0057] In this embodiment, the threshold value for determining humidity is set to 60%, but this value may be changed according to the display device, brightness settings, and environmental temperature.

[0058] <Other embodiments> Although the present invention has been described in detail above based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the gist of the present invention are also included in the present invention. Parts of the above-described embodiments may be combined as appropriate.

[0059] The present invention also includes cases where a software program that realizes the functions of the above-described embodiments is supplied to a system or device having a computer that can execute the program directly from a recording medium or via wired / wireless communication, and the program is executed.

[0060] Therefore, the program code itself that is supplied to and installed on a computer to realize the functional processing of the present invention also realizes the present invention. In other words, the computer program itself for realizing the functional processing of the present invention is also included in the present invention.

[0061] In this case, as long as it has the functionality of a program, the form of the program does not matter, such as object code, a program executed by an interpreter, or script data supplied to an OS.

[0062] The recording medium for supplying the program may be, for example, a hard disk, a magnetic recording medium such as a magnetic tape, an optical / magneto-optical storage medium, or a non-volatile semiconductor memory.

[0063] Another method of supplying the program is to store the computer program forming the present invention in a server on a computer network, and have connected client computers download the computer program.

[0064] In the above embodiment, it is stated that no condensation occurs, but this also includes cases where the level of condensation is light and there are no disadvantages for the user.

[0065] The disclosure of this specification includes the following display devices.

[0066] [Configuration 1] A display device having a display unit, An internal temperature measurement unit; an environmental temperature measurement unit; an acquisition means for acquiring a first brightness setting value which is a current brightness setting of the display unit; a control unit that determines whether condensation will occur on the display unit based on a first internal temperature measured by the internal temperature measurement unit, a first environmental temperature measured by the environmental temperature measurement unit, and the first brightness setting value acquired by the acquisition means, and if it is determined that condensation will occur, controls the display unit to display at a second brightness setting value that is smaller than the first brightness setting value and at which condensation will not occur.

[0067] [Configuration 2] a touch panel unit provided on an upper surface of the display unit; the internal temperature measurement unit measures the temperature between the display unit and the touch panel unit. 2. The display device according to configuration 1,

[0068] [Configuration 3] Further having a humidity measuring unit, When the humidity acquired by the humidity measuring unit is higher than the predetermined humidity, the control means determines whether condensation will occur on the display unit based on the first internal temperature, the first environmental temperature, and the first brightness setting value, and when it is determined that condensation will occur, controls the display unit to display at the second brightness setting value, and when the humidity acquired by the humidity measuring unit is equal to or lower than the predetermined humidity, controls the display unit to display at the first brightness setting value. 3. The display device according to configuration 1 or 2.

[0069] [Configuration 4] 4. The display device according to any one of configurations 1 to 3, characterized in that, in response to the display device being powered on, the control means acquires the first environmental temperature measured by the internal temperature measurement unit and the first brightness setting measured by the environmental temperature measurement unit, and switches between displaying the display unit at the first brightness setting value or displaying the display unit at the second brightness setting value based on the first internal temperature, the first environmental temperature, and the first brightness setting value.

[0070] [Configuration 5] The display device according to configuration 4, characterized in that, in response to the current brightness setting value being changed to a third brightness setting value, the control means acquires a second internal temperature measured by the internal temperature measurement unit and a second environmental temperature measured by the environmental temperature measurement unit, and determines whether condensation will occur on the display unit based on the second internal temperature, the second environmental temperature, and the third brightness setting value, and switches the display unit between displaying at the third brightness setting value or displaying at a fourth brightness setting value that is brighter than the third brightness setting value, depending on the determination result.

[0071] [Configuration 6] The display device described in any one of configurations 1 to 5, characterized in that the control means determines whether condensation will occur on the display unit based on a temperature gradient calculated based on the first internal temperature, the first ambient temperature, and the first brightness setting value, and an allowable temperature gradient corresponding to the ambient temperature.

[0072] [Configuration 7] 7. The display device according to configuration 6, wherein the control means determines the second brightness setting value based on the allowable temperature gradient and the first internal temperature.

Claims

1. A display device having a display unit, An internal temperature measurement unit; an environmental temperature measurement unit; an acquisition means for acquiring a first brightness setting value which is a current brightness setting of the display unit; a control unit that determines whether condensation will occur on the display unit based on a first internal temperature measured by the internal temperature measurement unit, a first environmental temperature measured by the environmental temperature measurement unit, and the first brightness setting value acquired by the acquisition means, and if it is determined that condensation will occur, controls the display unit to display at a second brightness setting value that is smaller than the first brightness setting value and at which condensation will not occur.

2. a touch panel unit provided on an upper surface of the display unit; the internal temperature measurement unit measures the temperature between the display unit and the touch panel unit.

2. The display device according to claim 1.

3. Further having a humidity measuring unit, When the humidity acquired by the humidity measuring unit is higher than the predetermined humidity, the control means determines whether condensation will occur on the display unit based on the first internal temperature, the first environmental temperature, and the first brightness setting value, and when it is determined that condensation will occur, controls the display unit to display at the second brightness setting value, and when the humidity acquired by the humidity measuring unit is equal to or lower than the predetermined humidity, controls the display unit to display at the first brightness setting value.

2. The display device according to claim 1.

4. 2. The display device according to claim 1, wherein, in response to the display device being powered on, the control means acquires the first environmental temperature measured by the internal temperature measurement unit and the first brightness setting measured by the environmental temperature measurement unit, and switches between displaying the display unit at the first brightness setting value or displaying the display unit at the second brightness setting value based on the first internal temperature, the first environmental temperature, and the first brightness setting value.

5. 5. The display device according to claim 4, wherein, in response to the current brightness setting value being changed to a third brightness setting value, the control means acquires a second internal temperature measured by the internal temperature measurement unit and a second environmental temperature measured by the environmental temperature measurement unit, determines whether condensation will occur on the display unit based on the second internal temperature, the second environmental temperature, and the third brightness setting value, and switches the display unit between displaying at the third brightness setting value or displaying at a fourth brightness setting value that is lower in brightness than the third brightness setting value, depending on the determination result.

6. 2. The display device according to claim 1, wherein the control means determines whether condensation will occur on the display unit based on a temperature gradient calculated based on the first internal temperature, the first ambient temperature, and the first brightness setting value, and an allowable temperature gradient corresponding to the ambient temperature.

7. 7. The display device according to claim 6, wherein the control means determines the second brightness setting value based on the allowable temperature gradient and the first internal temperature.

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