Display, method for controlling display, and program

Abstract

To provide a display that can reduce power consumption for preventing the occurrence of dew condensation, a method for controlling the display, and a program.SOLUTION: A display 100 having a light emitting unit 103 as a light source of a display unit 102 has: a luminance change amount detection unit 213 that acquires a luminance setting change amount α in switching from second luminance lower than first luminance to the first luminance; a dew condensation condition determination unit 214 that determines if dew condensation occurs in the display 100 by using the luminance setting change amount α; and a light emission driving unit 215 that, when it is determined that the dew condensation does not to occur in the display 100, turns on the light emitting unit 103 at the first luminance, and when it is determined that the dew condensation occurs in the display 100, turns on the light emitting unit 103 at third luminance lower than the first luminance and higher than the second luminance.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a display device, a control method for a display device, and a program. [Background technology]

[0002] In recent years, the increasing brightness and resolution of liquid crystal panels in display devices has led to an increase in the power consumption of liquid crystal panels and backlights. Furthermore, many display devices have traditionally combined separately purchased liquid crystal panels and touch panels, prioritizing the performance and cost of the liquid crystal panel. In such configurations, an air gap is often provided between the liquid crystal panel and the touch panel to reduce assembly costs.

[0003] However, in a structure with an air gap between the LCD panel and the touch panel, increased power consumption by the LCD panel and backlight can cause a temperature difference between the two, resulting in condensation on the glass on the air gap side of the touch panel. Condensation can make it difficult to see the LCD panel screen, which is a disadvantage for users. Furthermore, the size limitations of small LCD panels used in imaging and display devices such as video cameras make it difficult to implement condensation prevention measures such as incorporating a fan into the LCD panel unit.

[0004] As a technology related to this background, for example, Patent Document 1 describes a technology that gradually increases the backlight current while displaying an initial steady screen in order to prevent LED deterioration due to a sudden temperature change when starting up at a low temperature. Also, Patent Document 2 describes a technology to prevent condensation inside a touch panel, which prevents condensation by supplying power only to the input operation unit to increase the surface temperature of the touch panel even when the image forming apparatus is not in a normal operating state. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-124284 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-186327 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology of Patent Document 1 gradually increases the brightness of the LEDs only while the initial static screen is displayed, but the display time of the initial static screen alone does not affect the temperature of the LCD panel or touch panel, so condensation cannot be prevented. Furthermore, even if control to warm the LCD panel or touch panel continues after the display time of the initial static screen has ended, it is difficult for the user to determine when to end this control. Furthermore, the technology of Patent Document 2 prevents condensation by entering a special sleep state when the power is turned off, so when applied to battery-powered devices such as image capture and display devices, the operating time during normal use is shortened.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a display device, a control method for the display device, and a program that can reduce power consumption to prevent condensation from occurring. [Means for solving the problem]

[0008] In order to achieve the above object, the display device of the present invention is a display device having a light-emitting unit that is a light source for the display unit, and is characterized by comprising: a first acquisition means that acquires the amount of change when switching from a second luminance lower than a first luminance to the first luminance; a first determination means that determines whether condensation will occur on the display device using the amount of change acquired by the first acquisition means; a first lighting means that turns on the light-emitting unit at the first luminance when the first determination means determines that condensation will not occur on the display device; and a second lighting means that turns on the light-emitting unit at a third luminance lower than the first luminance and higher than the second luminance when the first determination means determines that condensation will occur on the display device. [Effects of the Invention]

[0009] According to the present invention, it is possible to reduce the power consumption required to prevent condensation from occurring. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram illustrating the configuration of a display device 100. FIG. [Figure 2] 1 is a system block diagram of a display device 100 according to a first embodiment. [Figure 3] 1 is a table showing the brightness of the light-emitting unit 103 and whether or not condensation occurs when the display device 100 is powered on (hereinafter referred to as "power-on"). [Figure 4] 10 is a table showing whether or not condensation occurs when the brightness of the light-emitting unit 103 is switched while the display device 100 is powered on (hereinafter referred to as "power-on"). [Figure 5] 4 is a flowchart showing a display control procedure of the display device 100 of the first embodiment. [Figure 6] FIG. 10 is a system block diagram of a display device 100 according to a second embodiment. [Figure 7] 10 is a flowchart showing a display control procedure of the display device 100 of the second embodiment. [Figure 8]10 is a graph showing the time that the light-emitting unit 103 is lit from power-on at the luminance of each luminance setting condition, and the temperature rise on the surface of the display unit 102 in the display device 100 of the second embodiment. [Figure 9] FIG. 10 is a system block diagram of a display device 100 according to a third embodiment. [Figure 10] 10 is a flowchart showing a display control procedure of the display device 100 of the third embodiment. [Figure 11] This is a graph showing the time that the power supply of the display device 100 is turned off (hereinafter referred to as "power-off time") and the temperature rise on the surface of the display unit 102 under each brightness setting condition when the power supply of the display device 100 is turned off (hereinafter referred to as "power-off time") in the third embodiment. [Figure 12] FIG. 10 is a system block diagram of a display device 100 according to a fourth embodiment. [Figure 13] 10 is a flowchart showing a display control procedure of the display device 100 of the fourth embodiment. [Figure 14] FIG. 10 is a system block diagram of a display device 100 according to a fifth embodiment. [Figure 15] 10 is a flowchart showing a display control procedure of the display device 100 of the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Each embodiment of the present invention will be described in detail below with reference to the drawings. However, the configurations described in each of the following embodiments are merely examples, and the scope of the present invention is not limited to the configurations described in each embodiment. For example, each component constituting the present invention can be replaced with any configuration that can perform the same function. Any component may also be added. Any two or more configurations (features) of each embodiment can also be combined. Each embodiment of the present invention will be described below with reference to FIGS. 1 to 15. Note that identical components are designated by the same reference numerals in each drawing, and description thereof will be omitted.

[0012] First Embodiment A first embodiment will be described below with reference to FIGS. 1 to 5. In the first embodiment, a display control procedure for temporarily lowering brightness when it is determined that there is a possibility of condensation using a brightness setting change amount acquired from brightness setting conditions, etc., will be described. First, the system control configuration of the display device of the first embodiment will be described. FIG. 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 or internally stored image data. The display device 100 has a touch panel unit 101, a display unit 102, a light-emitting unit 103, a control board 104, an air layer 105, and an exterior unit 106. The touch panel unit 101 (optical unit) is disposed opposite the display unit 102 via the air layer 105, and is an input device that outputs coordinate information according to a touched position.

[0013] The display unit 102 is superimposed on the light-emitting unit 103 on the air layer 105 side. As a result, the display unit 102 faces the touch panel unit 101 on the opposite side from the light-emitting unit 103, with the air layer 105 interposed therebetween. The display unit 102 is a functional unit that displays images according to video data by modulating light emitted from the light-emitting unit 103 with liquid crystal. The display unit 102 has liquid crystal shutter elements and color filters (not shown) arranged in a matrix. The liquid crystal shutter elements form images on the liquid crystal panel by changing the transmittance of 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 has 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. The display unit 102 displays images and GUI screens constituting a GUI (Graphical User Interface), etc., under the control of the control board 104.

[0014] 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 (hereinafter simply referred to as "light sources"). The light emitted from the light source of the light-emitting unit 103 is diffused in the planar direction by a diffusion plate (not shown), and serves as a light-emitting source with a predetermined light spread, irradiating the display unit 102 from behind. Note that, although an LED (light-emitting diode) or the like is used as the light-emitting element of the light source of the light-emitting unit 103, the light-emitting element is not limited to an LED, and 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.

[0015] There is an air layer 105 between the touch panel unit 101 and the display unit 102. When a large temperature difference occurs between the glass on the air layer 105 side of the touch panel unit 101 and the display unit 102, condensation occurs on the glass on the air layer 105 side of the touch panel unit 101. This is the location where condensation occurs in all cases described in the first embodiment. Therefore, the location where condensation occurs will not be specified in the following description. The exterior unit 106 supports the touch panel unit 101, the display unit 102, the light-emitting unit 103, and the control board 104.

[0016] FIG. 2 is a system block diagram of the display device 100 of the first embodiment. The display device 100 has an input operation unit 201 and a power operation unit 202 in addition to the above-mentioned touch panel unit 101, display unit 102, light-emitting unit 103, and control board 104. The input operation unit 201 is an input device for receiving user operations. The input operation unit 201 includes a character information input device such as a keyboard, a pointing device such as a mouse or touch panel, a button, a dial, a joystick, a touch sensor, a touchpad, and the like. The user performs various settings on the input operation unit 201. In this example, the user performs settings such as brightness and color. The power operation unit 202 is a selector switch. The user performs an operation on or off the power of the display device 100 using the power operation unit 202.

[0017] The control board 104 is a board on which a control circuit including a luminance setting storage unit 211, a luminance setting unit 212, a luminance change amount detection unit 213, a condensation condition determination unit 214, a light emission drive unit 215, and a system control unit 216 is mounted. Here, the control board 104 is disposed on the surface opposite to the light emitting surface (the upper surface in FIG. 1 ) of the light emitting unit 103, but may be configured separately from the display unit 102 and the light emitting unit 103. The system control unit 216 is connected to the input operation unit 201, the power operation unit 202, the luminance setting storage unit 211, the luminance setting unit 212, the luminance change amount detection unit 213, and the condensation condition determination unit 214, and controls the entire display device 100. In this way, the system control unit 216 realizes each process of the flowchart shown in FIG. 5, which will be described later.

[0018] The system control unit 216 may have, for example, a CPU, a ROM, and a RAM (not shown), and the CPU (computer) may read out a program stored in the ROM, load it into the RAM, and execute it to realize each process of the flowchart shown in Fig. 5 (to be described later). These points also apply to the flowcharts shown in Fig. 7, 10, 13, and 15 (to be described later).

[0019] The luminance setting storage unit 211 is a memory that stores a plurality of luminance setting conditions, including luminance that can be set by the user, and power values ​​for each luminance setting condition. The luminance setting conditions and power values ​​are parameters determined from the specifications of the display unit 102, light-emitting unit 103, and light-emitting drive unit 215 of the display device 100, but may also be determined by actual measurement. The luminance setting unit 212 sets the drive conditions for the light-emitting drive unit 215 by determining the luminance of the light-emitting unit 103 according to the luminance setting condition set by the user from the plurality of luminance setting conditions stored in the luminance setting storage unit 211.

[0020] The luminance change amount detection unit 213 detects the amount of luminance change from the luminance set by the user. For example, if the user changes the luminance from 250 [cd / m²], which is the luminance setting condition at power-on, to 750 [cd / m²], the amount of luminance change is 500 [cd / m²]. Furthermore, the luminance change amount detection unit 213 acquires a luminance setting change amount indicating a value corresponding to the amount of change in power from the detected amount of luminance change and the power value stored in the luminance setting storage unit 211. The condensation condition determination unit 214 determines whether or not condensation is likely to occur in the display device 100 using the luminance setting change amount acquired by the luminance change amount detection unit 213. If the condensation condition determination unit 214 determines that condensation is likely to occur, the lighting luminance of the light-emitting unit 103 is temporarily limited to a luminance setting condition that does not cause condensation. The luminance setting condition at this time is the maximum luminance setting condition among the luminance setting conditions that do not cause condensation. On the other hand, if the condensation condition determination unit 214 determines that there is no possibility of condensation occurring, the light emitting unit 103 lights up at the set brightness.

[0021] The light-emitting drive unit 215 can adjust the lighting luminance of the light-emitting unit 103. The light-emitting drive unit 215 drives the light-emitting unit 103 based on the luminance set by the user via the input operation unit 201. However, the light-emitting drive unit 215 switches the lighting luminance of the light-emitting unit 103 depending on the determination result received from the condensation condition determination unit 214. Here, the control signal that drives the light-emitting unit 103 is, for example, a signal that represents the pulse width of a pulse signal (current or voltage pulse signal) that is applied to the light source of the light-emitting unit 103. In this case, the light-emitting drive unit 215 adjusts the control signal to adjust the lighting luminance of the light-emitting unit 103 (PWM control). Note that the control signal may be a signal that represents the peak value of the pulse signal that is applied to the light source of the light-emitting unit 103 (PAM control), or a signal that represents both the pulse width and peak value of the pulse signal that is applied to the light source of the light-emitting unit 103 (PWM control).

[0022] Next, the mechanism by which condensation occurs on the glass on the air layer 105 side of the touch panel unit 101 will be described. Before the display device 100 is turned on, the temperature of the air layer 105 between the touch panel unit 101 and the display unit 102 is the same as the outside air temperature. When the display device 100 is turned on, the display unit 102, the light-emitting unit 103, and the control board 104 are driven, causing the temperature of the air layer 105 to rise rapidly. As a result, warm air flows toward the touch panel unit 101 in the air layer 105, causing condensation to occur on the glass on the air layer 105 side of the touch panel unit 101.

[0023] Such a temperature rise in the air layer 105 varies depending on the power of the light-emitting drive unit 215, and is mainly caused by the brightness of the light-emitting unit 103. For example, when the display device 100 is turned on at a luminance of 1500 [cd / m2], the temperature of the air layer 105 rises rapidly, causing condensation to form on the glass on the air layer 105 side of the touch panel unit 101. On the other hand, when the display device 100 is turned on at a luminance of 250 [cd / m2], the temperature of the air layer 105 rises only slightly, causing no condensation to form on the glass on the air layer 105 side of the touch panel unit 101.

[0024] FIG. 3 is a table (first data table) showing the brightness of the light-emitting unit 103 when the power is on and whether or not condensation occurs. FIG. 4 is a table (second data table) showing whether or not condensation occurs when the brightness of the light-emitting unit 103 is changed while the power is on. In each of the tables in FIG. 3 and FIG. 4, brightness indicates the brightness of the light-emitting unit 103. Power indicates the power consumption of the display device 100. Temperature rise indicates the temperature rise when the surface temperature of the display unit 102 reaches its maximum temperature after power is turned on. Condensation status indicates whether or not condensation occurs on the glass on the air layer 105 side of the touch panel unit 101.

[0025] The table in FIG. 3 shows the power, temperature rise, and condensation status for each brightness setting condition at power on. For example, when display device 100 is powered on with a brightness setting of 250 [cd / m2], the power is 675 [mW], the temperature rise is 5 [°C], and no condensation occurs. On the other hand, when display device 100 is powered on with a brightness setting of 1500 [cd / m2], the power is 4050 [mW], the temperature rise is 30 [°C], and condensation occurs. Note that the power, temperature rise, and condensation status may be obtained by substituting brightness into a calculation formula.

[0026] 4 shows the power increase and condensation state of the display device 100 for each brightness setting condition to which the brightness is changed from a certain brightness. For example, when the brightness setting condition is changed from 250 [cd / m2] to 500 [cd / m2], the power increase is 675 [mW] and condensation does not occur. On the other hand, when the brightness setting condition is changed from 250 [cd / m2] to 1500 [cd / m2], the power increase is 3375 [mW] and condensation occurs.

[0027] Furthermore, when the brightness setting condition is switched from 500 [cd / m2] to 1500 [cd / m2], the increased power is 2700 [mW], and condensation will occur. On the other hand, when the brightness setting condition is switched from 750 [cd / m2] to 1500 [cd / m2], the increased power is 2025 [mW], and condensation will not occur. Thus, in the first embodiment, when the power is turned on or when the brightness setting condition is changed while the power is on, if the power difference is 2100 [mW] or more, condensation will occur. Note that the increased power and condensation status may be obtained by substituting the brightness into a calculation formula.

[0028] FIG. 5 is a flowchart showing a display control procedure for the display device 100 of the first embodiment. Each process shown in the flowchart in FIG. 5 is realized by the system control unit 216. It should be noted that when the flowchart in FIG. 5 starts, the temperatures of the touch panel unit 101, the display unit 102, and the air layer 105 are assumed to be the same as the outside air temperature. When the flowchart in FIG. 5 starts, in step S501, the system control unit 216 supplies power to the display device 100 in response to a user operating the power operation unit 202. When power is supplied to the display device 100, a startup sequence for displaying an image on the display unit 102 starts. Furthermore, the system control unit 216 reads out, from the brightness setting storage unit 211, the brightness setting condition A that was set when the power was turned on.

[0029] In step S502, the system control unit 216, via the brightness change amount detection unit 213, acquires the brightness setting change amount α when the currently set brightness setting condition is switched to the brightness setting condition A that was set at power-on. That is, the brightness change amount detection unit 213 (first acquisition means) acquires the brightness setting change amount α (change amount) when the brightness of the currently set brightness setting condition (second brightness) is switched to the brightness of the brightness setting condition A that was set at power-on (first brightness) (acquisition step). However, the brightness setting change amount α at power-on, i.e., when the flowchart of FIG. 5 is started, is set to a value equivalent to the power under the brightness setting condition A that was set at power-on. According to the table of FIG. 3, for example, when the brightness of the brightness setting condition A that was set at power-on is 1500 [cd / m2], the power is 4050 [mW], so the brightness setting change amount α is 4050.

[0030] In step S503, system control unit 216 determines whether luminance setting change amount α satisfies the condensation condition using condensation condition determination unit 214 (first determination means) (determination step). This determines whether condensation is likely to occur. If system control unit 216 determines via condensation condition determination unit 214 that luminance setting change amount α satisfies the condensation condition, that is, if system control unit 216 determines that condensation is likely to occur, the process proceeds to step S504. On the other hand, if system control unit 216 determines via condensation condition determination unit 214 that luminance setting change amount α does not satisfy the condensation condition, that is, if system control unit 216 determines that condensation is unlikely to occur, the process proceeds to step S506.

[0031] In the first embodiment, as described above, condensation occurs when the power difference is 2100 mW or more. Therefore, when the brightness setting change amount α is 2100 or more, the brightness setting change amount α is determined to be a condition for condensation to occur, by the brightness setting change amount α. In contrast, when the brightness setting change amount α is less than 2100, the brightness setting change amount α is determined to be not a condition for condensation to occur, by the brightness setting change amount α. In this case, since the brightness setting change amount α acquired in step S502 is 4050, the brightness setting change amount α is determined to be a condition for condensation to occur, by the brightness setting change amount α. Therefore, the process proceeds to step S504.

[0032] In step S504, the system control unit 216 switches the brightness setting condition to a lower brightness setting condition than the brightness of the brightness setting condition A set at power-on, using the brightness setting unit 212. Furthermore, the system control unit 216 controls the light-emitting drive unit 215 (second lighting means) to light the light-emitting unit 103 at the brightness (third brightness) of the switched brightness setting condition (second lighting step). Here, the brightness setting condition lower than the brightness of the brightness setting condition A set at power-on is the maximum brightness setting condition among the brightness setting conditions that do not cause condensation. According to the table of FIG. 3, the maximum brightness among the brightness setting conditions that do not cause condensation is 750 [cd / m2]. Therefore, the brightness setting unit 212 switches from the brightness setting condition A set at power-on to the brightness setting condition with a brightness of 750 [cd / m2]. In the following description of the first embodiment, the brightness setting condition after this switching will be referred to as "brightness setting condition B."

[0033] In step S505, the system control unit 216 waits for a predetermined time to elapse by timing its internal clock. After the predetermined time has elapsed, the process returns to step S502. This causes step S502 and subsequent steps to be repeated. Here, the predetermined time is the time required for the surface temperature of the display unit 102 to reach the temperature required for brightness setting condition B after power-on. In other words, the predetermined time is the time required for the surface temperature of the display unit 102 to reach its maximum temperature after power-on under brightness setting condition B. In the first embodiment, the predetermined time is set to five minutes regardless of the brightness setting condition. Therefore, if brightness setting condition B, in which the brightness is 750 cd / m², is selected in step S504, the process returns to step S502 five minutes later. The process from step S502 onward is repeated until it is determined in step S503 that the brightness setting change amount α does not satisfy the condensation condition.

[0034] Specifically, in step S502, system control unit 216 acquires the brightness setting change amount α when the currently set brightness setting condition (i.e., brightness setting condition B) is switched to the brightness setting condition A that was set when the power was turned on, using brightness change amount detection unit 213. That is, brightness change amount detection unit 213 (first acquisition means) acquires the brightness setting change amount α when the brightness (third brightness) of the currently set brightness setting condition B is switched to the brightness (first brightness) of the brightness setting condition A that was set when the power was turned on.

[0035] According to the table in FIG. 4, the above-described change in the brightness setting condition corresponds to a change from a brightness of 750 [cd / m2] to a brightness setting condition of 1500 [cd / m2], resulting in an increased power of 2025 [mW]. As a result, the acquired brightness setting change amount α is 2025, which corresponds to the increased power and is smaller than 2100. Therefore, in step S503, the system control unit 216 determines, via the condensation condition determination unit 214, that the brightness setting change amount α does not satisfy the condensation occurrence condition, and the process proceeds to step S506. In step S506, the system control unit 216 causes the brightness setting unit 212 and the light-emitting drive unit 215 (first lighting means) to light the light-emitting unit 103 at the brightness of the brightness setting condition A that was set when the power was turned on (first lighting step). The flowchart in FIG. 5 then ends.

[0036] As described above, in the first embodiment, when the display device 100 determines that there is a possibility of condensation using the luminance setting change amount α obtained from the luminance setting conditions, etc., the display device 100 temporarily lowers the lighting luminance of the light-emitting unit 103. This allows the display device 100 to prevent condensation from occurring during normal use. Furthermore, when the display device 100 determines that there is no possibility of condensation occurring, the display device 100 does not temporarily lower the lighting luminance of the light-emitting unit 103, and therefore can end control for preventing condensation at an appropriate timing. Furthermore, in the display device 100, power for preventing condensation from occurring is not consumed when the power is turned off. As a result, the display device 100 can reduce power consumption for preventing condensation from occurring. Therefore, when the display device 100 is battery-powered, the battery drive time during normal use is not shortened.

[0037] Second Embodiment A second embodiment will be described below with reference to FIGS. 6 to 8. In the second embodiment, a display control procedure will be described in which the rising temperature of the surface of the display unit 102 and a virtual brightness setting condition are obtained using a brightness setting condition and a lighting time under that brightness setting condition, and the brightness is temporarily lowered when it is determined from the obtained results that there is a possibility of condensation. Note that in the second embodiment, only the differences from the first embodiment will be described. FIG. 6 is a system block diagram of a display device 100 of the second embodiment. The display device 100 has a lighting time calculation unit 601, a temperature calculation unit 602, and a virtual brightness setting calculation unit 603. This makes it possible for the display device 100 to determine whether or not there is a possibility of condensation even if the brightness setting condition is frequently changed by the user.

[0038] Lighting time calculation unit 601 calculates how many minutes light-emitting unit 103 remains lit at the luminance of the luminance setting condition before it was changed by the user. Temperature calculation unit 602 calculates the temperature rise of the surface of display unit 102 using the luminance setting condition before it was changed by the user and the time calculated by lighting time calculation unit 601. Virtual luminance setting calculation unit 603 calculates a virtual luminance setting condition by determining whether the temperature rise calculated by temperature calculation unit 602 is the same as the temperature rise that would occur if light-emitting unit 103 were lit at the luminance of a luminance setting condition.

[0039] 7 is a flowchart showing a display control procedure for the display device 100 of the second embodiment. The display control procedure for the display device 100 of the second embodiment is a control procedure when the user changes the brightness setting conditions before a predetermined time has elapsed since the light-emitting unit 103 was turned on or since the user changed the brightness setting conditions. Note that the predetermined time here refers to the time it takes for the rising temperature of the surface of the display unit 102 from when the power is turned on to reach the rising temperature of the brightness setting conditions before the change by the user. Each process shown in the flowchart of FIG. 7 is realized by the system control unit 216.

[0040] When the flowchart of FIG. 7 starts, in step S701, the user changes the luminance setting condition after the light-emitting unit 103 is turned on or before a predetermined time has elapsed since the user changed the luminance setting condition. In the second embodiment, it is assumed that the user changes the luminance setting condition from luminance setting condition A to luminance setting condition B. Also, it is assumed that the luminance (fourth luminance) of luminance setting condition A is 500 [cd / m2] and the luminance (first luminance) of luminance setting condition B is 1500 [cd / m2]. In step S702, the system control unit 216 acquires, via the lighting time calculation unit 601 (second acquisition means), the time (lighting time) before the luminance setting condition was changed, that is, the time during which the light-emitting unit 103 was turned on at the luminance of luminance setting condition A. In the second embodiment, it is assumed that the user changes the luminance setting condition to B after the light-emitting unit 103 has been turned on at the luminance of luminance setting condition A for 2.5 minutes.

[0041] In step S703, the system control unit 216 acquires, using the temperature calculation unit 602 (third acquisition means), the temperature rise (information about the temperature of the display unit) on the surface of the display unit 102 before the brightness setting condition is changed, i.e., under brightness setting condition A. FIG. 8 is a graph showing the time that the light-emitting unit 103 has been lit since power-on at the brightness of each brightness setting condition, and the temperature rise on the surface of the display unit 102. The graph in FIG. 8 may also be a data table. According to the graph in FIG. 8, in the second embodiment, the brightness of brightness setting condition A is 500 [cd / m2], and the lighting time of the light-emitting unit 103 is 2.5 minutes. Therefore, the temperature rise on the surface of the display unit 102 before the brightness setting condition is changed, i.e., under brightness setting condition A, is 5 [°C]. In step S704, the system control unit 216 acquires, using the virtual brightness setting calculation unit 603 (fourth acquisition means), the virtual brightness setting condition A' from the temperature rise acquired in step S705. According to the table of FIG. 3, in the second embodiment, the rising temperature is 5[° C.], so a virtual luminance setting condition A′ in which the luminance (first virtual luminance) is 250[cd / m 2 ] is acquired.

[0042] In step S705, the system control unit 216 acquires the luminance setting change amount α when the virtual luminance setting condition A' is switched to the luminance setting condition B by the luminance change amount detection unit 213. That is, the luminance change amount detection unit 213 (first acquisition means) acquires the luminance setting change amount α (change amount) when the luminance of the virtual luminance setting condition A' (first virtual luminance) is switched to the luminance of the luminance setting condition B (first luminance). In this example, the luminance of the virtual luminance setting condition A' is 250 [cd / m2], and the luminance of the luminance setting condition B is 1500 [cd / m2]. According to the table in FIG. 4, the above-mentioned switching of the luminance setting condition corresponds to the switching from the luminance of 250 [cd / m2] to the luminance setting condition of 1500 [cd / m2], so the increased power is 3375 [mW]. As a result, the acquired luminance setting change amount α becomes 3375, which is a value corresponding to the increased power.

[0043] In step S706, system control unit 216 determines, via condensation condition determination unit 214 (first determination means), whether brightness setting change amount α satisfies the condensation condition. This determines whether there is a possibility of condensation occurring. If system control unit 216 determines via condensation condition determination unit 214 that brightness setting change amount α satisfies the condensation condition, that is, if there is a possibility of condensation occurring, the process proceeds to step S707. On the other hand, if system control unit 216 determines via condensation condition determination unit 214 that brightness setting change amount α does not satisfy the condensation condition, that is, if there is no possibility of condensation occurring, the process proceeds to step S710.

[0044] In the second embodiment, condensation occurs when the power difference is 2100 [mW] or more. Therefore, when the brightness setting change amount α is 2100 or more, the condensation condition determination unit 214 determines that the brightness setting change amount α satisfies the condition for condensation to occur. In contrast, when the brightness setting change amount α is smaller than 2100, the condensation condition determination unit 214 determines that the brightness setting change amount α does not satisfy the condition for condensation to occur. In this case, the brightness setting change amount α calculated in step S705 is 3375, so the condensation condition determination unit 214 determines that the brightness setting change amount α satisfies the condition for condensation to occur. Therefore, the process proceeds to step S707.

[0045] In step S707, the system control unit 216 switches the brightness setting condition to a brightness setting condition lower than the brightness of brightness setting condition B, using the brightness setting unit 212. Furthermore, the system control unit 216 controls the light-emitting drive unit 215 (second lighting means) to light the light-emitting unit 103 at the brightness (third brightness) of the switched brightness setting condition. Here, the brightness setting condition lower than the brightness of brightness setting condition B is the maximum brightness setting condition among the brightness setting conditions under which condensation does not occur. According to the table of FIG. 4, among the brightness setting conditions to which the virtual brightness setting condition A', 250 [cd / m2], can be switched, the maximum brightness among the brightness setting conditions under which condensation does not occur is 1000 [cd / m2]. Therefore, the brightness setting unit 212 switches from brightness setting condition B to a brightness setting condition with a brightness of 1000 [cd / m2]. In the following description of the second embodiment, this switched brightness setting condition will be referred to as "brightness setting condition C."

[0046] In step S708, the system control unit 216 waits for a predetermined time to elapse by timing its internal clock. After the predetermined time has elapsed, the process proceeds to step S709. Here, the predetermined time is the time it takes for the surface temperature of the display unit 102 to rise from power-on to the temperature of brightness setting condition C. In other words, the predetermined time is the time it takes for the surface temperature of the display unit 102 to reach its maximum temperature from power-on under brightness setting condition C. In the second embodiment, the predetermined time is set to 5 minutes regardless of the brightness setting condition.

[0047] In step S709, the system control unit 216 acquires the luminance setting change amount α' when the currently set luminance setting condition C is switched to the luminance setting condition B by the luminance change amount detection unit 213. That is, the luminance change amount detection unit 213 (first acquisition means) acquires the luminance setting change amount α when the currently set luminance setting condition C (third luminance) is switched to the luminance setting condition B (first luminance). In this example, the luminance of the luminance setting condition C is 1000 [cd / m2], and the luminance of the luminance setting condition B is 1500 [cd / m2]. According to the table in FIG. 4, the above-mentioned switching of the luminance setting condition corresponds to the switching from the luminance of 1000 [cd / m2] to the luminance setting condition of 1500 [cd / m2], so the increased power is 1350 [mW]. As a result, the acquired luminance setting change amount α' becomes 1350, a value corresponding to the increased power. Then, the process returns to step S706.

[0048] In step S706, the system control unit 216 determines, via the condensation condition determination unit 214, whether the brightness setting change amount α' satisfies the condensation condition. The processes from step S707 onward are repeated until it is determined in step S706 that the brightness setting change amount α' does not satisfy the condensation condition. Here, the brightness setting change amount α' is 1350, which is smaller than 2100. Therefore, in step S706, the system control unit 216 determines, via the condensation condition determination unit 214, that the brightness setting change amount α' does not satisfy the condensation condition, and the process proceeds to step S710. In step S710, the system control unit 216 causes the brightness setting unit 212 and the light-emitting drive unit 215 (first lighting means) to light the light-emitting unit 103 at the brightness of the brightness setting condition B. The flowchart in FIG. 7 then ends.

[0049] As described above, in the second embodiment, display device 100 acquires the rising temperature of the surface of display unit 102 and the virtual brightness setting condition using the brightness setting condition and the lighting time under that brightness setting condition. Furthermore, when display device 100 determines that there is a possibility of condensation from the brightness setting change amount α(α') according to the acquired results, it temporarily lowers the lighting brightness of light-emitting unit 103. This allows display device 100 to prevent condensation from occurring even if the brightness setting condition is frequently changed by the user.

[0050] <Third embodiment> A third embodiment will be described below with reference to Figs. 9 to 11. In the third embodiment, the rising temperature of the surface of the display unit 102 and the virtual brightness setting conditions are acquired using the brightness setting conditions at the time of power off and the power off time, and a control procedure for temporarily lowering the brightness when it is determined from the acquired results that there is a possibility of condensation occurring will be described. Note that in the third embodiment, only the differences from the second embodiment will be described. Furthermore, in the third embodiment, it is assumed that in the display device 100 when the power is off, the surface temperature of the display unit 102 reaches the maximum temperature under the brightness setting conditions at the time of power off.

[0051] 9 is a system block diagram of a display device 100 according to a third embodiment. The display device 100 includes a power-off time calculation unit 901. The power-off time calculation unit 901 calculates the power-off time. In addition to calculating the temperature rise of the surface of the display unit 102 as described in the second embodiment, the temperature calculation unit 602 calculates the temperature rise of the surface of the display unit 102 using the power-off time and the luminance setting conditions at the time of power-off stored in the luminance setting storage unit 211. As in the second embodiment, the virtual luminance setting calculation unit 603 calculates the virtual luminance setting conditions by determining under which luminance setting conditions the temperature rise calculated by the temperature calculation unit 602 is the same as the temperature rise when the light-emitting unit 103 is turned on.

[0052] FIG. 10 is a flowchart showing a display control procedure for the display device 100 of the third embodiment. The display control procedure for the display device 100 of the third embodiment is a control procedure when the power is turned on again before the temperature drop time has elapsed since the power was turned off. Here, the temperature drop time is the time it takes for the surface temperature of the display unit 102 to reach the minimum temperature (i.e., the outside air temperature) after the power is turned off under the brightness setting conditions at the time of power off. Each process shown in the flowchart of FIG. 10 is realized by the system control unit 216. When the flowchart of FIG. 10 starts, in step S1001, the system control unit 216 supplies power to the display device 100 in response to a user's operation of the power operation unit 202. When power is supplied to the display device 100, a startup sequence for displaying an image on the display unit 102 starts. Furthermore, the system control unit 216 reads out the brightness setting condition A that was set when the power was turned on from the brightness setting storage unit 211. In the third embodiment, the brightness of the brightness setting condition A is set to 1500 [cd / m2].

[0053] In step S1002, the system control unit 216 (fifth acquisition means) reads out the brightness setting conditions at power off from the brightness setting storage unit 211. In the third embodiment, the brightness setting conditions are backed up when the power is off, so the brightness setting conditions at power off are the same as brightness setting condition A. Note that if the brightness setting conditions are not backed up when the power is off, the brightness setting conditions at power off may be different from brightness setting condition A. In step S1003, the system control unit 216 acquires the power off time using the power off time calculation unit 901 (sixth acquisition means). In the third embodiment, the power off time is set to 5 minutes.

[0054] In step S1004, the system control unit 216 acquires the rising temperature (information about the temperature of the display unit) of the surface of the display unit 102 using the luminance (fifth luminance) of the luminance setting condition when the power is off and the power-off time, using the temperature calculation unit 602 (seventh acquisition means). FIG. 11 is a graph showing the power-off time and the temperature rise of the surface of the display unit 102 for each luminance setting condition when the power is off. Note that the graph of FIG. 11 may also be a data table. According to the graph of FIG. 11, in the third embodiment, the luminance of luminance setting condition A, which is the luminance setting condition when the power is off, is 1500 [cd / m2] and the power-off time is 5 minutes, so the rising temperature of the surface of the display unit 102 is 15 [°C]. In step S1005, the system control unit 216 acquires the virtual luminance setting calculation unit 603 (eighth acquisition means) from the rising temperature acquired in step S1004, using the virtual luminance setting condition A'. According to the table of FIG. 3, in the third embodiment, the rising temperature is 15[° C.], so the virtual luminance setting condition A′ with a luminance of 750[cd / m 2 ] is acquired.

[0055] In step S1006, the system control unit 216 acquires the luminance setting change amount α when the virtual luminance setting condition A' is switched to the luminance setting condition A by the luminance change amount detection unit 213. That is, the luminance change amount detection unit 213 (first acquisition means) acquires the luminance setting change amount α (change amount) when the luminance of the virtual luminance setting condition A' (second virtual luminance) is switched to the luminance of the luminance setting condition A (first luminance). In this example, the luminance of the virtual luminance setting condition A' is 750 [cd / m2], and the luminance of the luminance setting condition A is 1500 [cd / m2]. According to the table of FIG. 4, the above-mentioned switching of the luminance setting condition corresponds to the switching from the luminance of 750 [cd / m2] to the luminance setting condition of 1500 [cd / m2], so the increased power is 2025 [mW]. As a result, the calculated luminance setting change amount α becomes 2025, which is a value corresponding to the increased power.

[0056] The processes in steps S1007 to S1011 are similar to the processes in steps S706 to S710 in the second embodiment, and therefore will not be described in detail below. However, brightness setting condition B in the second embodiment is replaced with brightness setting condition A. In the specific example described above, the brightness setting change amount α acquired in step S1006 is 2025, so the condensation condition determination unit 214 (first determination means) in step S1007 determines that the brightness setting change amount α does not satisfy the condensation occurrence condition. Therefore, the process proceeds to step S1011.

[0057] As described above, in the third embodiment, the display device 100 acquires the rising temperature and virtual brightness setting conditions on the surface of the display unit 102 using the brightness setting conditions when the power is off and the power-off time. Furthermore, the display device 100 temporarily lowers the brightness when it determines that there is a possibility of condensation occurring based on the brightness setting change amount α (α') corresponding to the acquired results. This allows the display device 100 to prevent condensation from occurring even if the power is turned on again before the temperature drop time has elapsed since the power was turned off.

[0058] <Fourth embodiment> A fourth embodiment will be described below with reference to Fig. 12 and Fig. 13. In the fourth embodiment, a control procedure will be described for displaying a message indicating a risk of condensation when it is determined that the luminance setting change amount α when the user changes the luminance setting condition is a condensation occurrence condition. Note that in the fourth embodiment, only the differences from the first embodiment will be described.

[0059] 12 is a system block diagram of a display device 100 according to a fourth embodiment. The display device 100 includes a condensation occurrence time calculation unit 1201 and a warning display unit 1202. When the condensation condition determination unit 214 determines that condensation may occur, the condensation occurrence time calculation unit 1201 notifies the warning display unit 1202 of the possibility of condensation occurrence, and then calculates the condensation occurrence time by referring to condensation occurrence information corresponding to the brightness setting change amount α. Here, it is assumed that the condensation occurrence time observed in an experiment in which the temperature conditions and brightness setting conditions of the display unit 102 were set in advance is stored in the condensation occurrence time calculation unit 1201 as the condensation occurrence information. The warning display unit 1202 displays the condensation occurrence time calculated by the condensation occurrence time calculation unit 1201 on the display unit 102.

[0060] FIG. 13 is a flowchart showing a display control procedure for the display device 100 of the fourth embodiment. Each process shown in the flowchart in FIG. 13 is implemented by the system control unit 216. The processes in steps S1301 to S1303 are similar to those in steps S501 to S503 of the first embodiment, and therefore will not be described in detail. However, if the system control unit 216 determines in step S1303 via the condensation condition determination unit 214 that the brightness setting change amount α does not satisfy the condensation condition, i.e., if the system control unit 216 determines that there is no possibility of condensation, the process returns to step S1302. As a result, the processes in steps S1302 and S1303 are repeated, thereby monitoring the user's operation to change the brightness setting condition. On the other hand, if the system control unit 216 determines in step S1303 via the condensation condition determination unit 214 that the brightness setting change amount α satisfies the condensation condition, i.e., if the system control unit 216 determines that there is a possibility of condensation, the process proceeds to step S1304.

[0061] In step S1304, system control unit 216 acquires the condensation occurrence time by referring to the condensation occurrence information corresponding to the brightness setting change amount α using condensation occurrence time calculation unit 1201 (ninth acquisition means). In step S1305, system control unit 216 transmits the condensation occurrence time and the like acquired in step S1304 to display unit 102 using warning display unit 1202. As a result, warning display unit 1202 (first warning display means) displays on display unit 102 the condensation occurrence time and a first alert message indicating that the current operation to change the brightness setting conditions poses a risk of condensation occurring.

[0062] In step S1306, system control unit 216 causes luminance setting unit 212 and light-emission driving unit 215 to switch to a luminance setting condition that is lower than the luminance of the currently set luminance setting condition, and lights up light-emitting unit 103 at the luminance of the switched luminance setting condition. Here, the luminance setting condition that is lower than the luminance of the currently set luminance setting condition is the luminance setting condition with the maximum luminance among the luminance setting conditions that do not cause condensation. Furthermore, system control unit 216 causes warning display unit 1202 (first warning display means) to display a second message on display unit 102 as an alert, indicating that the luminance setting condition has been switched to a luminance (third luminance) that is lower than the luminance of the currently set luminance setting condition.

[0063] In step S1307, the system control unit 216 waits for a predetermined time to elapse by timing its internal clock. After the predetermined time has elapsed, the process proceeds to step S1308. Here, the predetermined time is the same as the predetermined time in step S505 in the first embodiment. In step S1308, the system control unit 216 turns off the alert display by the warning display unit 1202 (first warning display means). As a result, the condensation occurrence time, the first message, and the second message are not displayed on the display unit 102.

[0064] In step S1309, system control unit 216 determines whether or not the power to display device 100 has been turned off. If system control unit 216 determines that the power to display device 100 has not been turned off, the process returns to step S1302. This continues the state of monitoring the user's operation to change the brightness setting condition until the power to display device 100 is turned off. On the other hand, if system control unit 216 determines that the power to display device 100 has been turned off, the flowchart in FIG. 13 ends.

[0065] As described above, in the fourth embodiment, when the display device 100 determines that the brightness setting change amount α when the user changes the brightness setting condition is a condition that causes condensation, the display device 100 can notify the user that the current change in the brightness setting condition poses a risk of condensation. Additionally, the display device 100 can notify the user of the condensation occurrence time and the fact that the brightness setting condition has been changed to a lower brightness than the brightness of the brightness setting condition changed by the user. Note that, in the fourth embodiment, the display unit 102 displays or hides the condensation occurrence time, the first message, and the second message, but this is not limiting. For example, the display unit 102 may display or hide at least one of the condensation occurrence time, the first message, and the second message.

[0066] Fifth Embodiment A fifth embodiment will be described below with reference to FIGS. 14 and 15. In the fifth embodiment, a control procedure for displaying a condensation disappearance time when it is determined that condensation may occur when the user changes the brightness setting condition will be described. Here, it is assumed that when the brightness setting condition is switched to one with a lower brightness than the brightness of the currently set brightness setting condition, the brightness is changed back to the brightness of the currently set brightness setting condition due to a forced cancellation operation by the user, and condensation occurs. In the following description of the fifth embodiment, the brightness setting condition with a lower brightness after this switching will be referred to as a "low brightness setting condition." In addition, in the fifth embodiment, only the differences from the fourth embodiment will be described.

[0067] 14 is a system block diagram of a display device 100 according to a fifth embodiment. The display device 100 includes a condensation disappearance time calculation unit 1401 instead of the condensation occurrence time calculation unit 1201, and further includes an environmental temperature measurement unit 1402 and a temperature calculation unit 602. The condensation disappearance time calculation unit 1401 calculates the condensation disappearance time by referring to the environmental temperature and internal temperature of the display device 100 and condensation disappearance information corresponding to the brightness setting conditions. Here, it is assumed that the condensation disappearance time observed in an experiment in which the temperature conditions and brightness setting conditions of the display unit 102 were set in advance is stored in the condensation disappearance time calculation unit 1401 as the condensation disappearance information. The condensation disappearance time calculated by the condensation disappearance time calculation unit 1401 is displayed on the display unit 102 by the warning display unit 1202.

[0068] The environmental temperature measurement unit 1402 directly measures the ambient temperature of the display device 100 or estimates it from the temperature of a measurable part. Examples of measurable parts include components adjacent to the display unit 102, the light source of the light-emitting unit 103, optical sheets such as a diffuser, an electric board, and electric components. In the fifth embodiment, the environmental temperature measurement unit 1402 is disposed outside the exterior unit 106 and is not affected by the internal temperature of the display device 100. The environmental temperature measurement unit 1402 uses a temperature sensor that detects temperature, such as a thermistor. Note that the internal temperature of the display device 100 is calculated using the temperature calculation unit 602, but a temperature sensor or the like may be provided to detect the internal temperature of the display device 100.

[0069] FIG. 15 is a flowchart of the control of the control board 104 according to the fifth embodiment. The processes shown in the flowchart in FIG. 15 are implemented by the system control unit 216. The processes in steps S1501 to S1503 are similar to those in steps S501 to S503 in the first embodiment, and therefore will not be described in detail. However, if the system control unit 216 determines in step S1503 via the condensation condition determination unit 214 that the brightness setting change amount α does not satisfy the condensation condition, i.e., if the system control unit 216 determines that there is no possibility of condensation, the process returns to step S1502. As a result, the processes in steps S1502 and S1503 are repeated, thereby monitoring the user's operation to change the brightness setting condition. On the other hand, if the system control unit 216 determines in step S1503 via the condensation condition determination unit 214 that the brightness setting change amount α satisfies the condensation condition, i.e., if there is a possibility of condensation, the process proceeds to step S1504.

[0070] In step S1504, system control unit 216 determines whether the low brightness setting condition has been forcibly canceled by the user using brightness change amount detection unit 213 (second determination means). If system control unit 216 determines through brightness change amount detection unit 213 that the low brightness setting condition has not been forcibly canceled by the user, the process returns to step S1502. As a result, the processes of steps S1502 and S1503, and further the process of step S1504 are repeated, thereby monitoring the user's operation to change the brightness setting condition. On the other hand, if system control unit 216 determines through brightness change amount detection unit 213 that the low brightness setting condition has been forcibly canceled by the user, the process proceeds to step S1505.

[0071] In step S1505, the system control unit 216 acquires the condensation disappearance time by using the condensation disappearance time calculation unit 1401 (tenth acquisition means) to refer to the ambient temperature and internal temperature of the display device 100 and the condensation disappearance information corresponding to the brightness setting change amount α. In step S1506, the system control unit 216 transmits the condensation disappearance time acquired in step S1505 to the display unit 102 by using the warning display unit 1202 (second warning display means). As a result, the warning display unit 1202 displays an alert of the condensation disappearance time on the display unit 102. In step S1507, the system control unit 216 waits for the condensation disappearance time to elapse from the display of the condensation disappearance time by measuring time with its built-in clock. Then, when the condensation disappearance time has elapsed from the display of the condensation disappearance time, the process proceeds to step S1508. In step S1508, the system control unit 216 turns off the alert display by using the warning display unit 1202 (second warning display means).

[0072] As a result, the condensation disappearance time is not displayed on the display unit 102. In step S1509, the system control unit 216 determines whether the power of the display device 100 has been turned off. If the system control unit 216 determines that the power of the display device 100 has not been turned off, the process returns to step S1502. As a result, the state of monitoring the user's operation to change the brightness setting condition continues until the power of the display device 100 is turned off. On the other hand, if the system control unit 216 determines that the power of the display device 100 has been turned off, the flowchart in FIG. 15 ends.

[0073] As described above, in the fifth embodiment, when the display device 100 determines that there is a possibility of condensation occurring when the user changes the brightness setting condition, it can notify the user of the time it will take for condensation to disappear. This allows the user to estimate the time at which condensation will disappear on the display device 100. Note that the display device 100 may display the result of the determination of whether there is a possibility of condensation occurring when the user changes the brightness setting condition on the display unit 102 as a message indicating whether condensation will occur when the user forcibly cancels the low brightness setting condition.

[0074] <Other> Although preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications and variations are possible within the scope of the present invention. For example, in each embodiment, the brightness setting change amount α(α') is calculated using the increased power obtained from a change in the brightness setting condition. However, since the change in the brightness setting condition and the increased power are uniquely determined, the brightness setting change amount α(α') may be obtained using only the change in the brightness setting condition. Similarly, in each embodiment, the possibility of condensation occurring is determined using the increased power obtained from the change in the brightness setting condition. However, since the change in the brightness setting condition and the increased power are uniquely determined, the possibility of condensation occurring may be determined using only the change in the brightness setting condition.

[0075] In each embodiment, the touch panel unit 101 is disposed so as to face the display unit 102 via the air layer 105. In this regard, a protective plate may be disposed on the surface of the display unit 102 facing the air layer 105. The present invention is also applicable to the display device 100 having a viewfinder-like configuration in which a lens group (optical unit) is disposed on the opposite side of the light-emitting unit 103 so as to face the display unit 102 via the air layer 105.

[0076] The present invention can also be realized by supplying a program that realizes one or more functions of each of the above embodiments to a system or device via a network or storage medium, and having one or more processors in the computer of the system or device read and execute the program. The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0077] The disclosure of each embodiment includes the following configurations, methods, and programs. (Configuration 1) A display device having a light-emitting unit that is a light source for a display unit, a first acquisition means for acquiring a change amount when switching from a second luminance lower than the first luminance to the first luminance; a first determination means for determining whether condensation will occur on the display device using the amount of change acquired by the first acquisition means; a first lighting means for lighting the light-emitting unit at the first luminance when the first determination means determines that condensation will not occur on the display device; and a second lighting means for lighting the light-emitting unit at a third brightness lower than the first brightness and higher than the second brightness when the first determination means determines that condensation will occur on the display device. (Configuration 2) The amount of change when switching from the second luminance to the first luminance is obtained from a first data table; 2. The display device according to configuration 1, wherein when the third luminance is the second luminance, the amount of change is obtained from a second data table different from the first data table. (Configuration 3) A second acquisition means for acquiring, as a lighting time, a time during which the light-emitting unit is lit at the fourth luminance when the luminance is changed from a fourth luminance lower than the first luminance to the first luminance by a user; a third acquisition means for acquiring information about a temperature of the display unit according to the fourth luminance and the lighting time; a fourth acquisition means for acquiring a first virtual luminance in accordance with information about a temperature of the display unit; 2. The display device according to configuration 1, wherein the first acquisition means acquires the amount of change by using the first virtual luminance as the second luminance. (Configuration 4) The first acquisition means The amount of change when switching from the second luminance to the first luminance is obtained from a first data table; When the third luminance is set to the second luminance, the amount of change is obtained from a second data table different from the first data table; 4. The display device according to configuration 3, wherein when the first virtual luminance is set to the second luminance, the amount of change is obtained from the second data table. (Configuration 5) A fifth acquisition means for acquiring, as a fifth luminance, the luminance of the light-emitting unit when the power supply of the display device is turned off; a sixth acquiring means for acquiring, as a power-off time, a time during which the power of the display device has been off when the power of the display device is turned on; a seventh acquisition means for acquiring information about a temperature of the display unit according to the fifth luminance and the power-off time; and an eighth acquisition means for acquiring a second virtual luminance in accordance with information about the temperature of the display unit, 4. The display device according to configuration 1 or 3, wherein the first acquisition means acquires the amount of change by using the second virtual luminance as the second luminance. (Configuration 6) The first acquisition means The amount of change when switching from the second luminance to the first luminance is obtained from a first data table; When the third luminance is set to the second luminance, the amount of change is obtained from a second data table different from the first data table; 6. The display device according to configuration 5, wherein when the second virtual luminance is the second luminance, the amount of change is obtained from the second data table. (Configuration 7) A display device described in any one of configurations 1 to 6, characterized in that the third brightness is the maximum brightness, among brightnesses lower than the first brightness, that allows the first acquisition means to acquire the amount of change when the first determination means determines that no condensation will occur on the display device. (Configuration 8) The display device described in Configuration 7, wherein the first acquisition means acquires the amount of change by setting the third brightness as the second brightness when the time has passed for the temperature of the display unit to reach its maximum temperature when the light-emitting unit is lit at the third brightness. (Configuration 9) A ninth acquisition means for acquiring, when the first determination means determines that condensation will occur on the display device, a time at which condensation will occur on the display device according to condensation occurrence information corresponding to the amount of change used by the first determination means; and a first warning display means for displaying an alert on the display unit regarding at least one of the condensation occurrence time, a first message indicating that condensation will occur on the display unit, and a second message indicating that the light-emitting unit is lit at the third brightness. (Configuration 10) The display device described in Configuration 9, wherein the first warning display means turns off the alert display on the display unit when the time has passed for the temperature of the display unit to reach its maximum temperature when the light-emitting unit is lit at the third brightness. (Configuration 11) A second determination means for determining whether or not a user has changed the third luminance to the first luminance when the first determination means determines that condensation will occur on the display device; a tenth acquisition means for acquiring, when the second determination means determines that the user has changed the third luminance to the first luminance, a time until condensation disappears on the display device according to condensation disappearance information corresponding to the amount of change used by the first determination means; and 11. The display device according to any one of configurations 1 to 10, further comprising: a second warning display means for displaying the condensation disappearance time on the display unit. (Configuration 12) The display device according to Configuration 11, wherein the second warning display means turns off the display of the condensation disappearance time on the display unit when the condensation disappearance time has elapsed since the condensation disappearance time was displayed on the display unit. (Configuration 13) The display device according to any one of configurations 1 to 12, wherein the amount of change is an increase in power of the display device when switching from the second luminance to the first luminance. (Configuration 14) A display device described in any one of configurations 1 to 13, characterized in that the first acquisition means repeats acquiring the amount of change by setting the third brightness as the second brightness until the first determination means determines that no condensation will occur on the display device. (Configuration 15) The display device according to any one of configurations 1 to 14, further comprising an optical section facing the display section on the opposite side to the light-emitting section with an air layer interposed therebetween. (Configuration 16) The display device according to configuration 15, wherein the optical unit is a touch panel. (Configuration 17) The display device according to configuration 15, wherein the optical section is a lens group. (Method 1) A method for controlling a display device having a light-emitting unit that is a light source for the display unit, comprising: an acquisition step of acquiring a change amount when switching from a second luminance lower than the first luminance to the first luminance; a determination step of determining whether condensation will occur on the display device using the amount of change acquired in the acquisition step; a first lighting step of lighting the light-emitting unit at the first luminance when it is determined in the determination step that condensation will not occur on the display device; a second lighting step of lighting the light-emitting unit at a third brightness lower than the first brightness and higher than the second brightness when the determination step determines that condensation will occur on the display device. (Program 1) A program for causing a computer to execute each means of the display device according to any one of configurations 1 to 17. [Explanation of symbols]

[0078] 100 display device 102 Display section 103 Light-emitting part 213 Brightness change amount detection unit (first acquisition means) 214 Condensation condition determination section (first determination means) 215 light emission driving unit (first lighting means) (second lighting means) α Brightness setting change amount (change amount)

Claims

1. A display device having a light-emitting unit that is a light source for a display unit, a first acquisition means for acquiring a change amount when switching from a second luminance lower than the first luminance to the first luminance; a first determination means for determining whether condensation will occur on the display device using the amount of change acquired by the first acquisition means; a first lighting means for lighting the light-emitting unit at the first luminance when the first determination means determines that condensation will not occur on the display device; a second lighting means for lighting the light-emitting unit at a third brightness lower than the first brightness and higher than the second brightness when the first determination means determines that condensation will occur on the display device.

2. The first acquisition means The amount of change when switching from the second luminance to the first luminance is obtained from a first data table; 2. The display device according to claim 1, wherein when the third luminance is set to the second luminance, the amount of change is obtained from a second data table different from the first data table.

3. a second acquisition means for acquiring, as a lighting time, a time during which the light-emitting unit is lit at the fourth luminance when the luminance is changed from a fourth luminance lower than the first luminance to the first luminance by a user; a third acquisition means for acquiring information about a temperature of the display unit according to the fourth luminance and the lighting time; a fourth acquisition means for acquiring a first virtual luminance in accordance with information relating to the temperature of the display unit; 2. The display device according to claim 1, wherein the first acquisition means acquires the amount of change by using the first virtual luminance as the second luminance.

4. The first acquisition means The amount of change when switching from the second luminance to the first luminance is obtained from a first data table; When the third luminance is set to the second luminance, the change amount is obtained from a second data table different from the first data table; 4. The display device according to claim 3, wherein when the first virtual luminance is set to the second luminance, the amount of change is obtained from the second data table.

5. a fifth acquisition means for acquiring, as a fifth luminance, the luminance of the light-emitting unit when the power supply of the display device is turned off; a sixth acquiring means for acquiring, as a power-off time, a time during which the power of the display device has been off when the power of the display device is turned on; a seventh acquisition means for acquiring information about a temperature of the display unit according to the fifth luminance and the power-off time; an eighth acquisition means for acquiring a second virtual luminance in accordance with information relating to the temperature of the display unit; 2. The display device according to claim 1, wherein the first acquisition means acquires the amount of change by using the second virtual luminance as the second luminance.

6. The first acquisition means The amount of change when switching from the second luminance to the first luminance is obtained from a first data table; When the third luminance is set to the second luminance, the change amount is obtained from a second data table different from the first data table; 6. The display device according to claim 5, wherein when the second virtual luminance is set to the second luminance, the amount of change is obtained from the second data table.

7. The display device according to claim 1, characterized in that the third brightness is the maximum brightness, among brightnesses lower than the first brightness, that allows the first acquisition means to acquire the amount of change when the first determination means determines that no condensation will occur on the display device.

8. The display device according to claim 7, characterized in that the first acquisition means acquires the amount of change by setting the third brightness as the second brightness when a time has passed during which the temperature of the display unit reaches a maximum temperature when the light-emitting unit is lit at the third brightness.

9. a ninth acquisition means for acquiring, when the first determination means determines that condensation will occur on the display device, a time period during which condensation will occur on the display device in accordance with condensation occurrence information corresponding to the amount of change used by the first determination means; and 2. The display device according to claim 1, further comprising: a first warning display means for displaying an alert on the display unit regarding at least one of the condensation occurrence time, a first message indicating that condensation will occur on the display unit, and a second message indicating that the light-emitting unit is lit at the third brightness.

10. 10. The display device according to claim 9, wherein the first warning display means turns off the alert display on the display unit when a time has passed during which the temperature of the display unit reaches a maximum temperature when the light-emitting unit is lit at the third brightness.

11. a second determination means for determining whether a user has changed the brightness from the third brightness to the first brightness when the first determination means determines that condensation will occur on the display device; and a tenth acquisition means for acquiring, when the second determination means determines that the user has changed the third luminance to the first luminance, a time until condensation disappears on the display device according to condensation disappearance information corresponding to the amount of change used by the first determination means; and 2. The display device according to claim 1, further comprising a second warning display means for displaying the condensation disappearance time on the display unit.

12. 12. The display device according to claim 11, wherein the second warning display means turns off the display of the condensation disappearance time on the display unit when the condensation disappearance time has elapsed since the condensation disappearance time was displayed on the display unit.

13. 2. The display device according to claim 1, wherein the amount of change is an increase in power of the display device when switching from the second luminance to the first luminance.

14. The display device according to claim 1 , wherein the first acquisition means repeatedly acquires the amount of change by setting the third luminance as the second luminance until the first determination means determines that no condensation will occur on the display device.

15. 2. The display device according to claim 1, further comprising an optical section that faces the display section on the opposite side to the light-emitting section via an air layer.

16. The display device according to claim 15, wherein the optical unit is a touch panel.

17. 16. The display device according to claim 15, wherein the optical unit is a lens group.

18. A method for controlling a display device having a light-emitting unit that is a light source for a display unit, comprising: an acquisition step of acquiring a change amount when switching from a second luminance lower than the first luminance to the first luminance; a determination step of determining whether condensation will occur on the display device using the amount of change acquired in the acquisition step; a first lighting step of lighting the light-emitting unit at the first luminance when it is determined in the determination step that condensation will not occur on the display device; a second lighting step of lighting the light-emitting unit at a third brightness lower than the first brightness and higher than the second brightness when the determination step determines that condensation will occur on the display device.

19. A program for causing a computer to execute each means of the display device according to claim 1.

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