Display device

Abstract

To provide a technique that can stabilize a luminance of an LED in a shorter time in a display device equipped with the LED.SOLUTION: A display device 1 includes a housing, a display panel, a light source, a first acquirer, a second acquirer, and a stabilizer. The display panel is provided in the housing. The light source is provided in the housing, and includes an LED that irradiates the display panel with light. The first acquirer acquires a first temperature in a first region including a region where the light source is disposed in the housing. The second acquirer acquires a second temperature in a second region different from the first region. The stabilizer has a first adjustment mode for lighting the LED with maximum luminance as an adjustment mode for stabilizing luminance of the LED. The stabilizer operates the LED in the first adjustment mode in a case where a temperature difference between the first temperature and the second temperature is a first threshold value or more.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a display device. [Background technology]

[0002] Conventionally, light emitting diodes (LEDs) have been used in the backlight of display devices. The brightness of LEDs depends on temperature. Since the screen brightness of a display device varies depending on the brightness of the backlight, it is necessary to wait until a stabilization process for stabilizing the brightness of the backlight is completed. Patent Document 1 discloses an LED brightness control circuit that quickly stabilizes the brightness of an LED. The LED brightness control circuit described in Patent Document 1 stabilizes the brightness of an LED by gradually increasing the current value of the LED based on the cathode potential of the LED and bringing it closer to a target current value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-121684 A Summary of the Invention [Problem to be solved by the invention]

[0004] Temperature changes in the environment in which the display device is placed can affect the brightness of the LEDs. Therefore, it may not be possible to stabilize the brightness of the LEDs in a short time just by measuring the temperature of the LED element itself.

[0005] An object of the present invention is to provide a technique for stabilizing the luminance of an LED in a shorter time period in a display device equipped with an LED. [Means for solving the problem]

[0006] The display device according to the present invention includes a housing, a display panel, a light source unit, a first acquisition unit, a second acquisition unit, and a stabilization unit. The display panel is provided within the housing. The light source unit is provided within the housing and includes an LED that irradiates light onto the display panel. The first acquisition unit measures a first temperature in a first region including a region in the housing where the light source unit is arranged. The second acquisition unit acquires a second temperature in a second region different from the first region. The stabilization unit has a first adjustment mode as an adjustment mode for stabilizing the brightness of the LED, and operates the LED in the first adjustment mode. The first adjustment mode is a mode in which the brightness of the LED is adjusted to maximum brightness when the temperature difference between the first temperature and the second temperature is equal to or greater than a first threshold value. Effect of the Invention

[0007] According to the display device, the brightness of the LEDs can be stabilized in a shorter time. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the appearance of a display device according to an embodiment. [Diagram 2] FIG. 2 is an exploded view showing a schematic configuration of the display device shown in FIG. [Diagram 3] FIG. 3 is a cross-sectional view showing a schematic cross section taken along line III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing a schematic cross section taken along line IV-IV in FIG. [Figure 5A] FIG. 5A is a schematic diagram showing a fan mounting member in the embodiment. [Figure 5B] FIG. 5B is a schematic diagram of the fan mounting member shown in FIG. 5A as viewed from the negative Z-axis direction side. [Figure 5C] FIG. 5C is a schematic diagram of the fan mounting member shown in FIG. 5A as viewed from the positive Z-axis direction. [Figure 5D] FIG. 5D is a schematic diagram of the fan mounting member shown in FIG. 5A as viewed from the negative X-axis direction. [Figure 5E] FIG. 5E is a schematic diagram of the fan mounting member shown in FIG. 5A as viewed from the positive direction of the X-axis. [Figure 6] FIG. 6 is a schematic cross-sectional view taken along line VI-VI shown in FIG. [Figure 7A] FIG. 7A is a diagram showing the path of the airflow generated by driving the first fan. [Figure 7B] FIG. 7B is a diagram showing the path of the airflow generated by driving the second fan. [Figure 8] FIG. 8 is a functional block diagram of the display device according to the embodiment. [Figure 9] FIG. 9 is an operational flow of the stabilization process in this embodiment. [Figure 10] FIG. 10 is a graph showing changes in LED luminance when stabilization processes are performed in the first adjustment mode and the second adjustment mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a display device according to an embodiment will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0010] 1 is a schematic diagram showing the appearance of a display device 1 according to an embodiment. The display device 1 is, for example, an 8K high-resolution display. As shown in FIG. 1, the display device 1 includes a housing 10. The front surface (negative Y-axis side) of the housing 10 has an opening 110a that exposes a display region R that displays an image. The rear surface (positive Y-axis side) of the housing 10 has air intakes 1211, 1212 and exhausts 1221, 1222.

[0011] Fig. 2 is an exploded view showing a schematic configuration of the display device 1 shown in Fig. 1. Fig. 3 is a cross-sectional view showing a schematic cross section taken along line III-III in Fig. 1. Fig. 4 is a cross-sectional view showing a schematic cross section taken along line IV-IV in Fig. 1. The internal structure of the display device 1 will be specifically described below with reference to Figs. 2 to 4.

[0012] 2 to 4, the display device 1 includes a front housing 110 and a rear housing 120 as the housing 10, a first chassis 20, and a second chassis 30. The first chassis 20 and the second chassis 30 are disposed between the front housing 110 and the rear housing 120. Specifically, the first chassis 20 is provided closer to the front housing 110 than the second chassis 30 is, and the second chassis 30 is provided between the first chassis 20 and the rear housing 120.

[0013] The projected area of ​​the second chassis 30 is smaller than that of the first chassis 20. The rear housing 120 has a first rear part 1201 that covers the first chassis 20 and a second rear part 1202 that covers the second chassis 30. A step is formed between the first rear part 1201 and the second rear part 1202. Due to this step, as shown in FIG. 3, a thickness L2 from the front surface (Y-axis negative direction side) of the front housing 110 to the second rear part 1202 is thicker than a thickness L1 from the front surface (Y-axis negative direction side) of the front housing 110 to the first rear part 1201. At the position of the step in the rear housing 120, the surface of the second chassis 30 on the rear housing 120 side comes into contact with the inner surface of the rear housing 120.

[0014] The display device 1 has a first internal space S1 (an example of a first internal space layer) and a second internal space S2 (an example of a second internal space layer) in the housing 10, and the second chassis 30 is disposed between the first internal space S1 and the second internal space S2. The first internal space S1 is an internal space on the first chassis 20 side, and the second internal space S2 is an internal space on the rear housing 120 side.

[0015] Furthermore, the display device 1 includes within the housing 10 a display module 210, a display control circuit board 230, an LED drive circuit board 240, a first temperature detection circuit 250 (an example of a first acquisition section), a main board 310, an image processing circuit board 320, a power supply unit 330, a plurality of fan mounting members 370, a plurality of first fans 350, a plurality of second fans 360, and a second temperature detection circuit 380 (an example of a second acquisition section).

[0016] The display module 210, the display control circuit board 230, the LED driving circuit board 240, the first temperature detection circuit 250, the image processing circuit board 320, the power supply unit 330, the multiple first fans 350, the multiple second fans 360, and the second temperature detection circuit 380 are electrically connected to the main board 310.

[0017] 2, the first chassis 20 supports a display module 210, a display control circuit board 230, and an LED drive circuit board 240. As shown in Fig. 3 and Fig. 4, in the first chassis 20, the display module 210 is disposed on the front housing 110 side, and the display control circuit board 230 and the LED drive circuit board 240 are disposed on the rear housing 120 side. The display module 210 is disposed in contact with the front housing 110 such that a display region R of the display module 210 is exposed from an opening 110a of the front housing 110.

[0018] 3 and 4, the display module 210 includes a display panel 211 and a backlight 212. In this embodiment, the display panel 211 is a liquid crystal display panel. The display panel 211 is electrically connected to a display control circuit board 230. The display control circuit board 230 includes a display panel drive circuit for driving the display panel 211.

[0019] The backlight 212 is a direct type backlight that radiates light to the entire back surface of the display panel 211. The backlight 212 includes a plurality of LEDs 212a and an LED board 212b that supports the plurality of LEDs 212a. The backlight 212 also includes an optical member (not shown) such as a reflective sheet for making light enter the display panel 211. The backlight 212 is electrically connected to an LED drive circuit board 240. The LED drive circuit board 240 is electrically connected to the display control circuit board 230. The LED drive circuit board 240 includes an LED drive circuit that turns on or off the plurality of LEDs 212a.

[0020] 2 includes a temperature sensor (not shown). The temperature sensor of the first temperature detection circuit 250 is provided in a first region R1 including the LED drive circuit board 240. In this embodiment, the first region R1 is in the vicinity of the LED drive circuit board 240, but the first region R1 may be in a range in which a temperature closer to the temperature of the LEDs 212a can be measured. The first temperature detection circuit 250 detects the temperature in the vicinity of the LED drive circuit board 240 at regular intervals, and outputs information indicating the detected temperature to the main board 310.

[0021] 2, the second chassis 30 supports a main board 310, an image processing circuit board 320, and a power supply unit 330 on the rear housing 120 side. Also, the second chassis 30 supports two sets of fan mounting members 370 arranged spaced apart from each other on the rear housing 120 side as shown in Fig. 2. The bottom of each fan mounting member 370 is connected to the second chassis 30, and a set of a first fan 350 and a second fan 360 is installed on the upper part of each fan mounting member 370.

[0022] The main board 310 includes a control circuit including a CPU (Central Processing Unit) and memories (ROM (Read Only Memory) and RAM (Random Access Memory)), a communication interface circuit for communicating with an external device, and the like (all not shown). The image processing circuit board 320 is electrically connected to the main board 310. The image processing circuit board 320 includes an image processing circuit for adjusting the color and brightness of a display image. The power supply unit 330 is electrically connected to each part of the display device 1 and supplies power to each connected part. The two sets of first and second fans 350 and 360 have their rotational operations controlled by the main board 310. The first fan 350 is used to exhaust air from the first internal space S1 (FIGS. 3 and 4), and the second fan 360 is used to exhaust air from the second internal space S2 (FIGS. 3 and 4). Hereinafter, the fan mounting members arranged on the X-axis positive side and the X-axis negative side of the second chassis 30 may be referred to as fan mounting members 370R and 370L, respectively.

[0023] 5A to 5E are schematic diagrams showing the structure of the fan mounting member 370R. FIG. 5A is a schematic diagram showing the fan mounting member 370R. FIG. 5B is a schematic diagram showing the fan mounting member 370R shown in FIG. 5A as viewed from the negative Z-axis direction. FIG. 5C is a schematic diagram showing the fan mounting member 370R shown in FIG. 5A as viewed from the positive Z-axis direction. FIG. 5D is a schematic diagram showing the fan mounting member 370R shown in FIG. 5A as viewed from the negative X-axis direction. FIG. 5E is a schematic diagram showing the fan mounting member 370R shown in FIG. 5A as viewed from the positive X-axis direction.

[0024] As shown in FIG. 5A to FIG. 5E, the fan mounting member 370R has a first mounting portion 3701 and a second mounting portion 3702. The first mounting portion 3701 has a hollow, substantially rectangular prism shape, and has a hollow area 3701h penetrating in the Y-axis direction. As shown in FIG. 5B to FIG. 5D, the second chassis 30 has an opening 30a penetrating the second chassis 30 at a position facing the first mounting portion 3701. The hollow area 3701h of the first mounting portion 3701 communicates with the first internal space S1 via the opening 30a. The first fan 350 is disposed on the upper surface (Y-axis positive direction side) of the first mounting portion 3701. The first mounting portion 3701 shields the opening 30a from the first fan 350 from the second internal space S2. Therefore, by driving the first fan 350, an airflow is formed that flows from the first internal space S1 through the opening 30a, through the hollow area 3701h of the first installation portion 3701, and toward the bottom of the first fan 350. In other words, the first installation portion 3701 and the opening 30a of the second chassis 30 are an example of an exhaust duct that guides the air in the first internal space S1 to the first fan 350. The first installation portion 3701 and the opening 30a prevent the air in the first internal space S1 from mixing with the air in the second internal space S2.

[0025] As shown in FIG. 5A to FIG. 5E, the second mounting portion 3702 has a substantially rectangular prism shape, and has openings 3702a to 3702e on all faces except the face that is the boundary with the first mounting portion 3701. As shown in FIG. 5B, 5C, and 5E, the opening 3702e on the bottom of the second mounting portion 3702 is blocked by the second chassis 30. That is, the inside 3702h of the second mounting portion 3702 communicates with the second internal space S2, but does not communicate with the first internal space S1. The second fan 360 is disposed on the upper surface of the second mounting portion 3702. Therefore, by driving the second fan 360, an airflow is formed that passes through the openings 3702a to 3702d of the second mounting portion 3702 from the second internal space S2 toward the bottom of the second fan 360.

[0026] Although not shown in the drawings, the fan mounting member 370L has a structure in which the positions of the first mounting portion 3701 and the second mounting portion 3702 of the fan mounting member 370R are reversed.

[0027] 2 to 4, the second temperature detection circuit 380 includes a temperature sensor (not shown). The temperature sensor of the second temperature detection circuit 380 is disposed in a second region R2 including the main substrate 310. In this embodiment, the second region R2 is on the main substrate 310, but the second region R2 may be a region different from the first region R1. The second temperature detection circuit 380 detects the temperature on the main substrate 310 at regular intervals, and outputs information indicating the detected temperature to the main substrate 310.

[0028] FIG. 6 is a schematic cross-sectional view taken along line VI-VI in FIG. 1. As shown in FIG. 2 and FIG. 6, the display device 1 further includes a blocking member 400 and a plurality of wirings 410 in the housing 10. The blocking member 400 is provided on the surface of the second chassis 30 on the rear housing 120 side. The blocking member 400 is made of an insulating material. As shown in FIG. 6, the second chassis 30 has a wiring opening 30b in the area where the blocking member 400 is provided. In the wiring opening 30b, the image processing circuit board 320 arranged on the second chassis 30 and the display control circuit board 230 arranged on the first chassis 20 are connected by the wiring 410. In addition, the main board 310 and the power supply unit 330 arranged on the second chassis 30 are connected by the wiring 410 to the display control circuit board 230 and the LED drive circuit board 240 arranged on the first chassis 20. The blocking member 400 covers the wiring opening 30b through which the wiring 410 is passed. In this manner, in this embodiment, the wiring 410 that connects the circuit members arranged on the first chassis 20 and the circuit members arranged on the second chassis 30 is concentrated in one place.

[0029] Returning to Figs. 2 to 4, the rear housing 120 is provided with intake ports 1211, 1212 and exhaust ports 1221, 1222. Specifically, the intake port 1211 (an example of a first intake port and a first intake section) is arranged in the first rear section 1201 of the rear housing 120, and the intake port 1212 (an example of a second intake port and a second intake section) and the exhaust ports 1221, 1222 are arranged in the second rear section 1202. The intake port 1211 provides communication between the first internal space S1 and the outside, and external air is taken into the first internal space S1. The intake port 1212 provides communication between the second internal space S2 and the outside, and external air is taken into the second internal space S2.

[0030] 4, the exhaust port 1221 (an example of a first exhaust port) is provided facing the first fan 350, and air sent out from the first fan 350 is exhausted from the exhaust port 1221. Specifically, as shown in FIG. 4, by driving the first fan 350, air in the first internal space S1 that has flowed into the first fan 350 through the opening 30a and the hollow region 3701h of the first installation portion 3701 is exhausted from the exhaust port 1221. In other words, the opening 30a, the first installation portion 3701, the first fan 350, and the exhaust port 1221 are an example of a first exhaust portion in this embodiment.

[0031] 3, the exhaust port 1222 (an example of a second exhaust port) is provided facing the second fan 360, and exhausts air sent out from the second fan 360. Specifically, as shown in FIG. 3, by driving the second fan 360, air in the second internal space S2 that has flowed into the second fan 360 through the interior 3702h of the second installation section 3702 is exhausted from the exhaust port 1222. That is, the second installation section 3702, the second fan 360, and the exhaust port 1222 are an example of a second exhaust section in this embodiment.

[0032] In this embodiment, the inside of the housing 10 of the display device 1 is separated by a first chassis 20 and a second chassis 30, and a first internal space S1 and a second internal space S2 are formed on the front side and the back side, respectively, of the housing 10. A fan (first fan 350) for exhausting air from the first internal space S1 and a fan (second fan 360) for exhausting air from the second internal space S2 are provided in the second internal space S2, and the air currents formed by each fan pass through different internal spaces.

[0033] 7A is a diagram showing the path of the airflow generated by driving the first fan 350, and FIG. 7B is a diagram showing the path of the airflow generated by driving the second fan 360. As shown by the arrows in FIG. 7A, the airflow generated by the first fan 350 passes through the first internal space S1 from the intake port 1211, passes through the opening 30a of the second chassis 30 and the hollow area 3701h of the first installation part 3701, flows into the first fan 350, and heads to the outside through the exhaust port 1221. As shown by the arrows in FIG. 7B, the airflow generated by the second fan 360 passes through the second internal space S2 from the intake port 1212, passes through the inside 3702h of the second installation part 3702, flows into the second fan 360, and heads to the outside through the exhaust port 1222. In this way, the air in the first internal space S1 and the second internal space S2 is not mixed with each other, and the air in each internal space is individually exhausted to the outside by driving the first fan 350 and the second fan 360. That is, the display control circuit board 230, the LED drive circuit board 240, and the LEDs 212a arranged in the first chassis 20, and the main board 310 arranged in the second chassis 30 are each individually cooled.

[0034] Next, functions of the display device 1 in this embodiment will be described with reference to Fig. 8. Fig. 8 is a functional block diagram of the display device 1.

[0035] As shown in FIG. 8, the display device 1 includes a control unit 1000, a display panel driving unit 1110, an LED driving unit 1120, an acquisition unit 1130, an image processing unit 1140, a first cooling unit 1150, a second cooling unit 1160, a display panel 211, and a backlight 212.

[0036] The display panel driver 1110 includes a display control circuit board 230 (see FIG. 2). The display panel driver 1110 displays an image on the display panel 211 by the display control circuit board 230 based on an image signal from the image processor 1140.

[0037] The LED driving unit 1120 includes an LED driving circuit board 240 (see FIG. 2). The LED driving unit 1120 controls the lighting of the backlight 212 by the LED driving circuit board 240 under the control of the control unit 1000.

[0038] The acquisition unit 1130 includes a first temperature detection circuit 250 and a second temperature detection circuit 380 (see FIG. 2). Under the control of the control unit 1000, the acquisition unit 1130 acquires a first temperature near the LED drive circuit board 240 by the first temperature detection circuit 250, and outputs the acquisition result to the control unit 1000. Also, under the control of the control unit 1000, the acquisition unit 1130 acquires a second temperature in the second internal space S2 by the second temperature detection circuit 380, and outputs the acquisition result to the control unit 1000. In other words, the first temperature is a temperature near the LED drive circuit board 240 that has a strong correlation with the temperature of the LED 212a, and can be estimated as the temperature of the LED 212a itself. The second temperature is a temperature in the second internal space S2 that is different from the first internal space S1 in which the LED 212a is provided, and corresponds to the temperature of the environment in which the LED 212a is provided.

[0039] The image processing unit 1140 includes an image processing circuit board 320 (see FIG. 2). It performs image correction processing for adjusting the color and brightness of the image on the image signal output from the control unit 1000, and outputs the image signal after the image correction processing to the display panel driving unit 1110.

[0040] The first cooling section 1150 includes a first fan 350 (see FIG. 2). Under the control of the control section 1000, the first cooling section 1150 exhausts the air in the first internal space S1 to the outside by the first fan 350.

[0041] The second cooling section 1160 includes a second fan 360 (see FIG. 2). Under the control of the control section 1000, the second cooling section 1160 exhausts the air in the second internal space S2 to the outside by the second fan 360.

[0042] The control unit 1000 includes a control circuit (not shown) having a CPU and memory (ROM and RAM) on the main board 310 (see FIG. 2). The control unit 1000 functions as a stabilization unit 1001, a cooling control unit 1002, and a display control unit 1003 by the CPU executing a control program stored in the ROM.

[0043] The stabilization unit 1001 has a first adjustment mode and a second adjustment mode as adjustment modes for performing stabilization processing of the luminance of the LED 212a. The stabilization unit 1001 controls the acquisition unit 1130, and switches the adjustment mode according to the temperature difference between the first temperature and the second temperature output from the acquisition unit 1130. In other words, the stabilization unit 1001 switches the adjustment mode according to the difference between the temperature (first temperature) of the LED drive circuit board 240, which has a correlation with the temperature of the LED 212a, and a temperature (second temperature) close to the temperature of the environment in which the LED 212a is provided.

[0044] The first adjustment mode is a mode in which the LEDs 212a of the backlight 212 are turned on so that the brightness of the backlight 212 is maximized. The second adjustment mode is a mode in which the LEDs 212a are turned on so that the brightness of the LEDs 212a is a predetermined target brightness. The predetermined target brightness is, for example, a brightness suitable for an image to be displayed.

[0045] Furthermore, the stabilization unit 1001 has a timer function and times the stabilization processing time. The stabilization unit 1001 performs the stabilization processing in at least one of the first adjustment mode and the second adjustment mode until the stabilization processing time exceeds a predetermined time. The stabilization processing may be performed, for example, when the power supply (not shown) of the display device 1 is turned on, or may be performed in response to a user operation. When the stabilization processing is performed in response to a user operation, for example, an operation button for instructing the stabilization processing may be provided on the display device 1, and the stabilization processing may be started when the operation button is pressed.

[0046] The cooling control unit 1002 controls the driving of the first cooling unit 1150 and the second cooling unit 1160 depending on the adjustment mode. Specifically, in the first adjustment mode, the cooling control unit 1002 stops the first fan 350 and drives only the second fan 360. In the second adjustment mode, the cooling control unit 1002 drives the first fan 350 and the second fan 360.

[0047] The display control unit 1003 generates an image signal of an image to be displayed and outputs it to the image processing unit 1140 .

[0048] (operation) Next, the operation of the stabilization process in the display device 1 will be described with reference to Fig. 9. Fig. 9 shows the operation flow of the stabilization process in this embodiment.

[0049] In step S11, the display device 1 starts acquiring the first temperature and the second temperature in the acquiring unit 1130, and starts measuring the temperature difference between the acquired first temperature and the second temperature. Specifically, the stabilizing unit 1001 drives the first temperature detection circuit 250 and the second temperature detection circuit 380 to detect the first temperature (T1) near the LED drive circuit board 240 and the second temperature (T2) near the main board 310 at regular intervals. Then, the stabilizing unit 1001 starts measuring the temperature difference ΔT (=T1-T2) between the first temperature (T1) and the second temperature (T2) detected at regular intervals.

[0050] If the measured temperature difference ΔT is not equal to or greater than the first threshold (eg, 14° C. or greater) (step S12: No), the display device 1 sets the adjustment mode to the first adjustment mode by the control unit 1000 (step S13).

[0051] Specifically, by setting the first adjustment mode, the stabilization unit 1001 outputs a lighting control signal indicating the maximum brightness of the LED 212a to the LED drive unit 1120. In this case, a PWM signal with a duty ratio of, for example, 100% is input to the LED 212a from the LED drive circuit (not shown) in the LED drive circuit board 240 as a PWM signal based on the lighting control signal. In addition, the cooling control unit 1002 stops the first fan 350 and drives only the second fan 360. This causes the air in the second internal space S2 in which the main board 310 is provided to be exhausted to the outside. That is, by the first adjustment mode, the inside of the first internal space S1 in which the LED drive circuit board 240 is provided is not cooled, and the LED 212a is turned on at the maximum brightness.

[0052] In step S14, if the temperature difference ΔT between the first temperature and the second temperature is not equal to or greater than the second threshold (e.g., 40° C. or greater) (step S14: No) and a predetermined time (e.g., 10 minutes) has not elapsed since the start of the stabilization process (step S15: No), the display device 1 continues the processes of steps S13 and S14. In other words, if it is within the predetermined time after the start of the first adjustment mode, the first adjustment mode is continued until the temperature difference ΔT between the first temperature and the second temperature becomes equal to or greater than the second threshold.

[0053] In step S14, if the temperature difference ΔT between the first temperature and the second temperature becomes equal to or greater than the second threshold (e.g., 40°C or greater) and a predetermined time (e.g., 10 minutes) has not elapsed since the start of the stabilization process (step S14: Yes, step S6: No), the display device 1 switches the adjustment mode from the first adjustment mode to the second adjustment mode via the control unit 1000 (step S17).

[0054] Specifically, by switching to the second adjustment mode, the stabilization unit 1001 outputs a lighting control signal indicating a target brightness to the LED drive unit 1120. In this case, a PWM signal having a duty ratio of, for example, about 80% is input to the LED 212a from the LED drive circuit (not shown) in the LED drive circuit board 240 as a PWM signal based on the lighting control signal. Then, the cooling control unit 1002 drives the first fan 350 and the second fan 360. As a result, not only the air in the second internal space S2 but also the air in the first internal space S1 in which the LED drive circuit board 240 is provided is exhausted to the outside. In other words, by switching to the second adjustment mode, the insides of the first internal space S1 and the second internal space S2 are cooled, and the LED 212a is turned on at the target brightness.

[0055] When the temperature difference ΔT is 40° C. or more, the temperature of the LED driving circuit board 240 rises sufficiently, the LEDs 212a themselves are sufficiently warmed, and the brightness of the LEDs 212a is stable. In this state, when the first adjustment mode is switched to the second adjustment mode, the first internal space S1 is cooled, and the LED driving circuit board 240 and the LEDs 212a are cooled. As a result, the brightness of the LEDs 212a converges to the target brightness.

[0056] The display device 1 continues the stabilization process in the first adjustment mode or the second adjustment mode until a predetermined time has elapsed since the start of the stabilization process (step S15: No, step S16: No) by the control unit 1000. Then, when the predetermined time has elapsed since the start of the stabilization process (step S15: Yes, step S16: Yes), the display device 1 ends the stabilization process by the control unit 1000.

[0057] Fig. 10 is a graph showing the change in luminance of the LED 212a when the stabilization process is performed in the first adjustment mode and the second adjustment mode. In Fig. 10, the dashed curve (A) shows the change in luminance of the LED 212a when the stabilization process is performed in the second adjustment mode, and the solid curve (B) shows the change in luminance of the LED 212a when the stabilization process is performed in the first adjustment mode.

[0058] As shown by curve (A) and curve (B), in any adjustment mode, the luminance of LED212a decreases over time and then stabilizes. In curve (A), the time when the luminance stabilizes is t2 (minutes), while in curve (B), the time when the luminance stabilizes is t1 (t1 < t2) (minutes). That is, the time when the luminance stabilizes is shorter for curve (B). In the first adjustment mode, since LED212a is lit at the maximum luminance, the temperature of the LED drive circuit board 240 and LED212a rises faster than in the second adjustment mode where LED212a is lit at a target luminance lower than the maximum luminance. Furthermore, in the first adjustment mode, since the first internal space S1 including the LED drive circuit board 240 is not cooled, the temperature of the LED drive circuit board 240 and LED212a can be raised more rapidly compared to the second adjustment mode where the first internal space S1 and the second internal space S2 are cooled. As a result, the luminance of LED212a stabilizes more rapidly, and the stabilization process of the LED212a luminance can be completed in a short time.

[0059] Also, the display device 1 in the present embodiment performs the luminance stabilization process in consideration of the ambient temperature that affects the luminance of LED212a. Therefore, compared with the case where the stabilization process is performed based only on the temperature of LED212a, the stabilization process can be more surely completed in a short time.

[0060] The embodiments according to the present invention have been described above. However, the present invention is not limited to the above embodiments, and can be implemented in various aspects without departing from the gist thereof. The drawings schematically show each component mainly for easy understanding, and the thickness, length, number, etc. of each illustrated component are different from the actual ones for convenience of drawing creation. Also, the shape, dimensions, etc. of each component shown in the above embodiments are examples and are not particularly limited, and various changes can be made without substantially departing from the effects of the present invention.

[0061] (1) The second temperature may be the temperature outside the display device 1, that is, the installation environment temperature of the place where the display device 1 is installed. In this case, the display device 1 is provided with an acquisition means for successively acquiring the installation environment temperature wirelessly or via a wired connection. Then, the stabilization unit 1001 may take the installation environment temperature acquired by the acquisition means as the second temperature, and measure the temperature difference between the first temperature and the second temperature.

[0062] (2) The second temperature detection circuit 380 may be provided in the second internal space S2 near the air intakes 1211, 1212 of the first rear portion 1201 and the second rear portion 1202. Since the air intakes 1211, 1212 are in communication with the outside of the housing 10, the difference between the temperature near the air intakes 1211, 1212 and the outside temperature is small. Therefore, a temperature closer to the temperature of the environment in which the display device 1 is installed can be detected as the second temperature. In other words, the second region R2 may be any region other than the first region R1 in the housing 10, and preferably any region in which a temperature closer to the outside temperature can be measured.

[0063] (3) The first region R1 is not limited to a region in the vicinity of the LED driving circuit board 240. The first region R1 may be a region including the LEDs 212a and separated from the LED driving circuit board 240. In this case, the first acquisition unit may measure the temperature at a position separated from the LED driving circuit board 240, and estimate the temperature of the LEDs 212a (the first temperature) from the measured temperature using a predetermined formula.

[0064] (4) In the stabilization process, in the first adjustment mode, at least only the lighting control of the LED 212a may be performed by the stabilization unit 1001. In other words, in the first adjustment mode, the drive control of the first fan 350 and the second fan 360 by the cooling control unit 1002 is not essential.

[0065] (5) Although the display device 1 has two internal spaces (the first internal space S1 and the second internal space S2) that are shielded from each other within the housing 10, the housing 10 may have only one internal space.

[0066] (6) In step S12: No in FIG. 9, a condition for setting the first adjustment mode may be added that the difference between the acquired first temperature and a predetermined target temperature of the LED 212a is not equal to or greater than a predetermined threshold. That is, when the measured temperature difference ΔT is not equal to or greater than the first threshold (for example, 14° C. or greater) (step S12: No) and the difference between the first temperature and the target temperature is not equal to or greater than a predetermined threshold, the control unit 1000 may set the first adjustment mode as the adjustment mode. When performing stabilization processing after the LED 212a is turned on, the LED 212a may be warmed to some extent. Therefore, when the temperature difference ΔT is equal to or greater than the first threshold and the difference between the first temperature and the target temperature is equal to or greater than a certain value, the adjustment mode may be set to the first adjustment mode, and otherwise to the second adjustment mode. [Industrial Applicability]

[0067] The present invention can be used in liquid crystal displays. [Explanation of symbols]

[0068] 1:Display device 10: Housing 20: First Chassis 30: 2nd chassis 30A: Second chassis 30a: opening 30b: Wiring opening 30c: Intake opening 110: Front case 120: Rear case 210: Display module 211: Display panel 212: Backlight 212a: LED 212b: LED board 230: Display control circuit board 240: LED driver circuit board 250: First temperature detection circuit 310: Main board 320: Image processing circuit board 330: Power supply unit 350: 1st fan 360: Second Fan 370: Fan installation parts 380: Second temperature detection circuit 400: Closure member 410: Wiring 500: Intake duct 1000: Control section 1001: Stabilization section 1002: Cooling control unit 1120: LED driver 1130:Detection unit 1150: 1st cooling section 1160:Second cooling section 1201: 1st back part 1201A: Back part 1202:Second back part 1211, 1212: Air intake 1221, 1222: Exhaust port 3701: 1st installation part 3702:Second installation part R1: 1st area R2: 2nd area S1: 1st internal space S2:Second internal space

Claims

1. A housing and A display panel provided in the housing; a light source unit provided in the housing and including an LED (Light Emitting Diode) that irradiates light onto the display panel; a first acquisition unit that acquires a first temperature in a first region including a region in which the light source unit is disposed within the housing; A second acquisition unit that acquires a second temperature in a second region different from the first region; a stabilization unit that has a first adjustment mode for stabilizing the brightness of the LED, the first adjustment mode being for lighting the LED at maximum brightness, and that operates the LED in the first adjustment mode when a temperature difference between the first temperature and the second temperature is not equal to or greater than a first threshold value; Equipped with the second area is an area other than the first area within the housing, the housing has a front surface exposing a display area of ​​the display panel and a rear surface opposite to the front surface, In the housing, A first chassis; a second chassis facing the first chassis and disposed on the rear side of the first chassis; a first internal space layer that is an internal space between the first chassis and the second chassis and includes the first region; a second internal space layer that is an internal space between the second chassis and the rear surface of the housing and includes the second region; Further comprising: A display device, wherein the first internal space layer and the second internal space layer are shielded from each other.

2. the stabilization unit further has, as the adjustment mode, a second adjustment mode in which the LED is operated to have a target luminance lower than the maximum luminance; 2. The display device of claim 1, wherein the stabilization unit operates the LED in the first adjustment mode, and switches from the first adjustment mode to the second adjustment mode when the temperature difference becomes equal to or greater than a second threshold value that is greater than the first threshold value and when the operating time in the first adjustment mode is less than a predetermined time.

3. The display device according to claim 1 , wherein the second region is an outside of the housing.

4. a first exhaust unit including a first fan and driving the first fan to exhaust air of the first internal space layer to the outside of the housing; a second exhaust unit including a second fan and driving the second fan to exhaust air in the second internal space layer to the outside of the housing; Further equipped with The first exhaust unit stops driving the first fan in the first adjustment mode and drives the first fan in the second adjustment mode, The display device according to claim 2 , wherein the second exhaust section drives the second fan in the first adjustment mode and the second adjustment mode.

5. the first exhaust section further includes an exhaust duct section that penetrates the second chassis and is shielded from the second internal space layer, and a first exhaust port provided on the rear surface of the housing, and exhausts air of the first internal space layer from the exhaust duct section to the outside via the first exhaust port; The display device according to claim 4 , wherein the second exhaust section further includes a second exhaust port provided on the rear surface of the housing, and exhausts air in the second internal space layer to the outside from the second exhaust port.

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