Display device

Abstract

To provide a display device capable of improving visibility when a light-emitting part emits light.SOLUTION: A display device is provided with a light-emitting unit 20 that emits light by itself, a body part 2 in which the light-emitting unit 20 is arranged, a control unit 60 that controls luminance of the light-emitting unit 20, and an irradiation light detection unit 50 that detects light irradiated from a direction in which the light-emitting unit 20 emits light. The control unit 60 increases the luminance of the light-emitting unit 20 when the irradiation light detection unit 50 detects light irradiated from the direction in which the light-emitting unit 20 emits light, in a state where the light-emitting unit 20 emits light.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] When construction work is carried out on a road where vehicles are traveling, it is necessary to indicate the construction site to pedestrians and vehicle drivers in order to ensure the safety of the workers performing the work and the safety of the vehicles traveling on the road. Known means for indicating construction sites in this way include construction lights and display devices that use illuminants.

[0003] For example, the display device described in Patent Document 1 includes a solar cell, a power storage unit that stores power converted by the solar cell, a battery storage unit that stores a dry cell battery and at least a portion of which is formed from a transparent member, a light-emitting unit that emits light using power supplied from the power storage unit or the dry cell battery, and a power supply switching unit that switches the power source for power supplied to the light-emitting unit between the power storage unit and the dry cell battery. This makes it possible for the display device described in Patent Document 1 to avoid a situation in which the light-emitting unit cannot emit light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-27058 Summary of the Invention [Problem to be solved by the invention]

[0005] In situations where the light-emitting unit of a display device located near a construction site is emitting light, i.e., when it is dark around the display device, such as at night, vehicles traveling on the road will be traveling with their headlights on. Therefore, when a traveling vehicle approaches the display device, the light emitted from the vehicle's headlights will also be irradiated onto the display device.

[0006] However, when light from the vehicle's headlights is irradiated onto the display device, the light from the headlights is reflected by the entire display device, and the light from the light-emitting portion of the display device in an illuminating state may be mixed up with the reflected light of the headlights reflected by the entire display device. In this case, it becomes difficult for the driver of the vehicle to see the light from the light-emitting portion of the display device, and the driver of the vehicle may have difficulty recognizing the information shown by the display device using the light from the light-emitting portion as well.

[0007] In particular, in recent years, as vehicle headlights have increasingly been converted to LEDs and become brighter, the brightness of the light reflected from the display device when the light from the headlights is irradiated onto the display device has also increased, making the light from the light-emitting unit of the display device more difficult to see than ever before.For this reason, there is room for improvement in terms of visibility in dark surroundings, such as at night, in display devices that allow the vehicle driver to recognize desired information by emitting light from the light-emitting unit.

[0008] The present invention has been made in view of the above, and has an object to provide a display device that can improve visibility when a light-emitting portion emits light. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems and achieve the object, the display device of the present invention comprises a self-luminous light-emitting unit, a main body unit in which the light-emitting unit is arranged, a control unit that controls the brightness of the light-emitting unit, and an irradiation light detection unit that detects light irradiated from the direction in which the light-emitting unit irradiates light, and is characterized in that the control unit increases the brightness of the light-emitting unit when the irradiation light detection unit detects light irradiated from the direction in which the light-emitting unit irradiates light while the light-emitting unit is emitting light.

[0010] In the display device, it is preferable that the control unit increases the brightness of the light-emitting unit and then returns the brightness of the light-emitting unit to its original value after a predetermined time has elapsed.

[0011] Furthermore, it is preferable that the display device further includes an illuminance detection unit that detects ambient illuminance, and the control unit causes the light-emitting unit to emit light when the illuminance detected by the illuminance detection unit is equal to or lower than a predetermined threshold, and turns off the light-emitting unit when the illuminance detected by the illuminance detection unit is higher than the threshold.

[0012] Furthermore, it is preferable that the above display device further comprises a solar cell that converts light energy into electricity and a storage unit that stores the electricity converted by the solar cell, and that the light-emitting unit emits light using the electricity supplied from the storage unit.

[0013] Furthermore, it is preferable that the above display device is provided with a communication unit that wirelessly transmits and receives signals from the control unit, the control unit controls the blinking of the light-emitting unit, and the control unit communicates with the control unit of another display device via the communication unit and synchronizes the blinking of the light-emitting unit between the display devices that communicate with each other to perform the blinking control.

[0014] Furthermore, it is preferable that the above display device further includes a battery housing section that houses a primary battery, and the light-emitting section emits light using power supplied from the storage section or power supplied from the primary battery housed in the battery housing section.

[0015] Furthermore, the above display device preferably has a first unit including the solar cell and the power storage unit, a second unit including the solar cell, the power storage unit, and the communication unit, and a third unit including the solar cell, the power storage unit, and the battery accommodating unit, and the first unit, the second unit, and the third unit are each detachable from the main body unit and can each be attached to the main body unit in a replaceable manner.

[0016] In addition, the display device preferably includes a canopy that blocks light irradiated onto the irradiated light detection unit from above.

[0017] The display device preferably further includes a cover that covers the irradiated light detection unit, and at least a part of the cover is made of a transparent material. [Effects of the Invention]

[0018] The display device according to the present invention has an effect of improving visibility when the light-emitting portion emits light. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a front view of a display device according to an embodiment. [Figure 2] FIG. 2 is a view taken along the line AA in FIG. [Figure 3] FIG. 3 is a view taken along the arrow BB in FIG. [Figure 4] FIG. 4 is a view taken along the arrow CC in FIG. [Figure 5] FIG. 5 is a detailed schematic diagram of the portion of the solar unit where the irradiated light detector is disposed. [Figure 6] FIG. 6 is a view taken along the arrow DD in FIG. [Figure 7] FIG. 7 is a functional block diagram of the display device according to the embodiment. [Figure 8] FIG. 8 is a front view of the display device to which the second unit is attached. [Figure 9] FIG. 9 is a view taken along the arrow EE in FIG. [Figure 10] FIG. 10 is a functional block diagram of the display device shown in FIG. [Figure 11] FIG. 11 is a front view of the display device to which the third unit is attached. [Figure 12] FIG. 12 is a view taken along the arrow FF in FIG. [Figure 13] FIG. 13 is a functional block diagram of the display device shown in FIG. [Figure 14] FIG. 14 is an explanatory diagram showing a state in which the legs of the display device shown in FIG. 2 are opened. [Figure 15]FIG. 15 is an explanatory diagram showing a state in which the legs of the display device shown in FIG. 3 are opened. [Figure 16] FIG. 16 is a transition diagram of the light emitting state of the light emitting unit of the display device. [Figure 17] FIG. 17 is an explanatory diagram for creating a synchronization group for synchronizing the light emission of the light-emitting parts of display devices. [Figure 18] FIG. 18 is an explanatory diagram for flashing the light emitting units in synchronized flashing patterns. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, embodiments of a display device according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are replaceable and easily conceivable by those skilled in the art, or those that are substantially the same.

[0021] [Embodiment] FIG. 1 is a front view of a display device 1 according to an embodiment. FIG. 2 is a view taken along the arrow AA in FIG. 1. In the following description, the up-down direction of the display device 1 in its normal use state will be described as the up-down direction of the display device 1, the upper side of the display device 1 in its normal use state will be described as the upper side of the display device 1, and the lower side of the display device 1 in its normal use state will be described as the lower side of the display device 1. The display device 1 according to this embodiment includes a main body 2 and a solar unit 30 attached to the main body 2. The main body 2 has a substantially rectangular plate-like panel 3, and the panel 3 is attached to a frame 4, which is a frame-like member formed in a substantially rectangular shape that is roughly the same as the outer periphery of the panel 3.

[0022] A display unit 6 that displays desired information is disposed on one surface in the thickness direction of the panel 3 attached to the frame 4, and is formed in an arbitrary shape using a member of a color different from the color of the panel 3. For example, if the panel 3 is white, the display unit 6 is formed in a color that stands out against the panel 3, such as red or blue, and it is preferable that a retroreflective reflective material is used for the display unit 6. In this embodiment, the display unit 6 is formed in the shape of an arrow that points in one direction in the longitudinal direction of the rectangular shape of the panel 3. This makes it possible for the display device 1 according to this embodiment to inform pedestrians and vehicle drivers who view the display device 1 that the direction of the arrow in the shape of the display unit 6 is a safe direction to proceed.

[0023] A plurality of self-emitting light-emitting units 20 are arranged in the main body 2 of the display device 1 formed in this manner. The light-emitting units 20 are made of, for example, LEDs (Light Emitting Diodes), and a plurality of light-emitting units 20 are arranged on the display unit 6 along the shape of the display unit 6 provided on the panel 3 of the main body 2. Therefore, when the light-emitting units 20 are lit, the plurality of light-emitting units 20 arranged on the display unit 6 can light up in a shape that follows the shape of the display unit 6.

[0024] 3 is a view taken along the arrow BB in FIG. 1. FIG. 4 is a view taken along the arrow CC in FIG. 3. In the display device 1, a leg 10 is disposed on the surface of the panel 3 opposite the surface on which the display unit 6 is provided in the thickness direction. The leg 10 is formed in a roughly U-shape and is attached to the frame 4 so as to be rotatable around a pivot 12. More specifically, the width of the open side of the U-shape of the leg 10 is approximately the same as the width of the panel 3 and the frame 4 in the short direction, and both ends of the open side of the leg 10 are attached to the frame 4 via the pivot 12. The pivot 12 connects the leg 10 to the frame 4 so as to be rotatable relative to the frame 4 around a pivot axis oriented along the short direction of the panel 3, etc.

[0025] The pivoting portion 12 is disposed near one end in the longitudinal direction of the frame portion 4. When the leg portion 10 connected to the frame portion 4 by the pivoting portion 12 is aligned with the frame portion 4, the closed side of the U-shape is positioned near the other end of the frame portion 4 in the longitudinal direction.

[0026] The display device 1 also has a solar unit 30 equipped with a solar cell 40 (see FIG. 2), and the frame 4 is provided with a unit mounting bracket 16 for attaching the solar unit 30. The solar unit 30 can be attached to and detached from the unit mounting bracket 16 using mounting members 17 (see FIG. 1). Therefore, the solar unit 30 can be attached to and detached from the main body 2 by being attached to and detached from the unit mounting bracket 16.

[0027] The solar unit 30, which can be attached to and detached from the unit mounting bracket 16, can also be electrically attached and detached from the light-emitting unit 20 arranged in the main body 2. That is, electric wires (not shown) that can carry electricity extend from the solar unit 30 and the light-emitting unit 20, and connectors (not shown) are arranged on each electric wire. The solar unit 30 and the light-emitting unit 20 can be electrically connected and disconnected by connecting and disconnecting the connectors arranged on each electric wire.

[0028] The unit mounting bracket 16 provided on the frame 4 of the main body 2 is located near the center of the frame 4 in the longitudinal direction. The unit mounting brackets 16 are also located on both of the two long sides of the frame 4, allowing the solar unit 30 to be detachably attached to both sides. In this way, the unit mounting brackets 16 to which the solar unit 30 can be attached are rotatably connected to the frame 4.

[0029] More specifically, the unit mounting bracket 16 is connected to the frame 4 so as to be rotatable about an axis member 18 extending in the longitudinal direction of the frame 4. Therefore, the unit mounting bracket 16 on the side where the solar unit 30 is attached can be rotated about the axis member 18, so that the portion of the unit mounting bracket 16 where the solar unit 30 is attached is positioned on the side of the panel 3 where the display unit 6 is located. In this way, the unit mounting bracket 16 positions the solar unit 30 attached to the unit mounting bracket 16 on the side of the panel 3 where the display unit 6 is located.

[0030] On the other hand, of the two unit mounting brackets 16 arranged on the frame portion 4, the unit mounting bracket 16 on the side to which the solar unit 30 cannot be attached is rotated around the axis member 18, and positioned on the side opposite to the side on which the display unit 6 of the panel 3 is located, as in the lower unit mounting bracket 16 in Figure 4.

[0031] In other words, the unit mounting bracket 16 can be rotated approximately 270° around the axis member 18, and by rotating it around the axis member 18, it can be switched between a state in which the solar unit 30 is attached and used, and a state in which it is positioned on the back side, which is the side opposite to the side on which the display unit 6 of the panel 3 is located.

[0032] The display device 1 according to this embodiment is used with the short side direction of the panel 3 and frame 4 oriented close to the vertical direction, and the solar unit 30 is attached to the unit mounting bracket 16 that is located on the upper side when the display device 1 is in use. Therefore, when using the display device 1, the unit mounting bracket 16 located on the upper side is rotated to a position where the solar unit 30 can be attached, and the unit mounting bracket 16 located on the lower side is rotated to a position on the rear side of the panel 3.

[0033] 1 illustrates a form in which the display device 1 is used with the arrow on the display unit 6 pointing to the left when viewed from the side on which the display unit 6 is provided, but the display device 1 may also be used with the arrow pointing to the right. When using the display device 1 with the arrow on the display unit 6 pointing to the right, the solar unit 30 is attached to the unit mounting bracket 16 that is located on the upper side of the two unit mounting brackets 16 when using the display device 1 with the arrow pointing to the right.

[0034] When the main body 2 is oriented so that the arrow on the display unit 6 points to the right, the unit mounting bracket 16 for attaching the solar unit 30 is rotated upward to position the unit mounting bracket 16 above the frame 4. The solar unit 30 is attached to the unit mounting bracket 16 positioned above the frame 4 in this way. This allows the display device 1 to be used with the solar unit 30 positioned at the top end of the main body 2, even when the arrow on the display unit 6 is oriented to point to the right.

[0035] The solar unit 30 has a solar cell 40 that converts light energy into electricity, and a secondary battery 45 that is a power storage unit that stores the electricity converted by the solar cell 40. The light emitting unit 20 emits light using power supplied from the secondary battery 45 of the solar unit 30. The solar unit 30 has an upper cover 35 and a lower cover 36, which are formed in a shape that has a space inside when the upper cover 35 and the lower cover 36 are joined together. In other words, the upper cover 35 and the lower cover 36 are provided as a housing for the solar unit 30.

[0036] The upper cover 35 and the lower cover 36 are joined together in such a manner that, when the solar unit 30 is attached to the unit mounting bracket 16 and the display device 1 is oriented for use, the upper cover 35 is relatively positioned on the upper side and the lower cover 36 is positioned below the upper cover 35. When attaching the solar unit 30 to the unit mounting bracket 16, the lower side of the lower cover 36 is attached to the unit mounting bracket 16.

[0037] Solar cell 40 and secondary battery 45 are placed in a space formed inside upper cover 35 and lower cover 36 by joining upper cover 35 and lower cover 36, and are covered by upper cover 35 and lower cover 36. Upper cover 35 and lower cover 36 are each covers made of a transparent material that transmits light.

[0038] The solar cell 40, which is arranged inside the upper cover 35 and the lower cover 36, is arranged closer to the upper cover 35 than the secondary battery 45. Therefore, when the solar unit 30 is attached to the unit mounting bracket 16, the solar cell 40 is arranged above the secondary battery 45. The solar cell 40, which is arranged above the secondary battery 45, can receive ambient light, such as sunlight, that is irradiated onto the solar unit 30 from above through the upper cover 35, and can convert the energy of the received light into electricity.

[0039] The solar unit 30 also has an irradiated light detection unit 50. The irradiated light detection unit 50 uses a light detection sensor, such as a photodiode or photoresistor, that can output an electrical signal in response to received light. The irradiated light detection unit 50 is located on the same side of the solar unit 30 as the side on which the light-emitting unit 20 located on the main body 2 is located when the solar unit 30 is attached to the unit mounting bracket 16. In other words, the irradiated light detection unit 50 is located on the solar unit 30 facing the same side as the light-emitting unit 20 located on the main body 2. This makes it possible for the irradiated light detection unit 50 to detect light irradiated from the direction in which the light-emitting unit 20 emits light.

[0040] Figure 5 is a detailed schematic diagram of the portion of the solar unit 30 where the irradiated light detection unit 50 is located. Figure 6 is a view taken along the arrow DD in Figure 5. The irradiated light detection unit 50 is located below the solar cell 40 in the solar unit 30. Therefore, light irradiated from above onto the irradiated light detection unit 50, which is capable of detecting light, is blocked by the solar cell 40. In other words, the solar cell 40 is also provided as a canopy 38 that blocks light irradiated onto the irradiated light detection unit 50 from above.

[0041] The irradiated light detection unit 50, which is disposed below the solar cell 40, is covered by the lower cover 36. More specifically, the lower cover 36 has a recess 36a that is recessed from the outer circumferential surface of the lower cover 36 and has an opening that opens toward the side where the irradiated light detection unit 50 detects light. The irradiated light detection unit 50 is disposed at the bottom of the recess 36a formed in the lower cover 36. Therefore, the lower cover 36, which is a cover made of a transparent material, covers the irradiated light detection unit 50.

[0042] 7 is a functional block diagram of a display device 1 according to an embodiment. The display device 1 has a control unit 60 that can switch the light emission state of the light emitting unit 20 by controlling the power supplied to the light emitting unit 20. The control unit 60 is configured as an electronic control device that includes a processing unit having a CPU (Central Processing Unit) and the like, and a storage unit such as RAM (Random Access Memory). The control unit 60 is disposed inside the solar unit 30, and is disposed below the solar cell 40 in the space formed by the upper cover 35 and the lower cover 36. The solar cell 40, the secondary battery 45, and the irradiated light detection unit 50 are connected to the control unit 60.

[0043] When the light-emitting unit 20 arranged in the main body 2 is electrically connected to the solar unit 30, the light-emitting unit 20 is electrically connected to the control unit 60. Furthermore, the solar unit 30 is also provided with a power switch (not shown) that switches between a state in which the display device 1 is in use and a state in which the display device 1 is stopped from being used.

[0044] In this embodiment, the solar cell 40 is also used as an illuminance detection unit 55 that detects the ambient illuminance, and doubles as the illuminance detection unit 55. That is, the solar cell 40 converts the light energy received by the solar cell 40 into electric power, and the electric power generated by the solar cell 40 changes depending on the amount of light received by the solar cell 40. That is, the solar cell 40 generates a lot of electric power when the amount of light received is large, and generates less electric power when the amount of light received is small, so that it is possible to detect the ambient illuminance of the display device 1 by detecting the electric power generated by the solar cell 40.

[0045] The secondary battery 45 serves as a power storage unit that stores the power converted by the solar cell 40, and serves as a power source for the power used by the display device 1. The secondary battery 45 receives power converted by the solar cell 40 from ambient light via the control unit 60 and stores the power. The secondary battery 45 also supplies the power used by the light-emitting unit 20 to the light-emitting unit 20 via the control unit 60, and the light-emitting unit 20 emits light using the power supplied from the secondary battery 45. In other words, the light-emitting unit 20 emits light using the power converted by the solar cell 40 that is supplied via the secondary battery 45. The control unit 60 is also driven by the power supplied from the secondary battery 45.

[0046] The control unit 60 can control the light emission of the light-emitting unit 20 by controlling the power supplied to the light-emitting unit 20. That is, the control unit 60 can control the brightness of the light-emitting unit 20 by controlling the power supplied to the light-emitting unit 20, and can make the light-emitting unit 20 blink by repeatedly switching the light-emitting unit 20 between emitting and turning off.

[0047] For example, the control unit 60 causes the light-emitting unit 20 to emit light when the illuminance detected by the illuminance detection unit 55 is equal to or lower than a predetermined threshold, and turns off the light-emitting unit 20 when the illuminance detected by the illuminance detection unit 55 is higher than the threshold. Furthermore, when the irradiated light detection unit 50 detects light irradiated from the direction in which the light-emitting unit 20 irradiates light while the light-emitting unit 20 is emitting light, the control unit 60 increases the luminance of the light-emitting unit 20, and after increasing the luminance of the light-emitting unit 20, returns the luminance of the light-emitting unit 20 to its original value after a predetermined time has elapsed.

[0048] Furthermore, the intervals at which the light-emitting units 20 are turned on and off when the control unit 60 causes the light-emitting units 20 to blink are preset as blinking patterns of the light-emitting units 20 and stored in a storage unit of the control unit 60. When causing the light-emitting units 20 to emit light, the control unit 60 controls the blinking of the light-emitting units 20 based on the blinking patterns thus set. Note that the blinking control of the light-emitting units 20 may involve simultaneously blinking all of the multiple light-emitting units 20, or may involve staggering the blinking timing of the multiple light-emitting units 20 so that the light from the light-emitting units 20 flows in the direction of the arrow shown on the display unit 6.

[0049] Furthermore, the display device 1 according to the embodiment is provided with a plurality of types of solar units 30 with different configurations, and it is possible to use interchangeable solar units 30. That is, the display device 1 is provided with a first unit 31, a second unit 32, and a third unit 33 as the solar units 30, each with a different configuration.

[0050] These first unit 31, second unit 32, and third unit 33 are each detachable from the main body 2, and can be attached interchangeably to the main body 2. That is, the first unit 31, second unit 32, and third unit 33 can be attached to and detached from the main body 2 by being attached to and detached from the unit mounting bracket 16, and can be electrically connected to and disconnected from the light-emitting unit 20.

[0051] Of these, the first unit 31 is the solar unit 30 shown in Figures 1 to 7. That is, the first unit 31 includes a solar cell 40 and a secondary battery 45.

[0052] FIG. 8 is a front view of the display device 1 to which the second unit 32 is attached. FIG. 9 is a view taken along the arrow EE in FIG. 8. FIG. 10 is a functional block diagram of the display device 1 shown in FIG. 8. In addition to the first unit 31, the second unit 32 of the solar unit 30 includes a communication unit 70 that wirelessly transmits and receives signals from the control unit 60. That is, the second unit 32 includes a solar cell 40, a secondary battery 45, and the communication unit 70. Like the solar cell 40 and the secondary battery 45, the communication unit 70 is arranged inside the upper cover 35 and lower cover 36 that are coupled to each other. The communication unit 70 has an antenna 71 and a communication control unit 72, and is connected to the control unit 60.

[0053] Of these, the antenna 71 is an antenna capable of transmitting and receiving radio waves used for wireless communication. The communication control unit 72 is capable of performing communication control when transmitting and receiving signals using radio waves. In detail, the communication control unit 72 is capable of acquiring signals carried by the radio waves from the radio waves received by the antenna 71 and transmitting the acquired signals to the control unit 60, and also capable of transmitting signals from the control unit 60 via radio waves from the antenna 71. The communication unit 70 is capable of transmitting and receiving signals by using radio waves in the 2.4 GHz frequency band, for example.

[0054] When the second unit 32 is attached to the main body 2 of the display device 1, the second unit 32 is provided with a communication unit 70, which enables wireless communication with other display devices 1. That is, the control unit 60 of the second unit 32 attached to the main body 2 communicates with the control unit 60 of the other display devices 1 via the communication unit 70.

[0055] In this way, the display device 1 capable of wireless communication with other display devices 1 can transmit and receive signals, such as control signals, between the control units 60 of the display devices 1 when controlling the blinking of the light-emitting units 20, through wireless communication between the display devices 1. In other words, the control units 60 of the display devices 1 to which the second units 32 are attached can transmit and receive control signals via wireless communication between the communication units 70 of the respective display devices 1. Therefore, the control unit 60 of the second unit 32 attached to the main body 2 can, for example, synchronize the blinking of the light-emitting units 20 between the display devices 1 that are communicating with each other, thereby controlling the blinking of the light-emitting units 20.

[0056] FIG. 11 is a front view of the display device 1 to which the third unit 33 is attached. FIG. 12 is a view taken along the arrow FF in FIG. 11. FIG. 13 is a functional block diagram of the display device 1 shown in FIG. 11. The third unit 33 of the solar unit 30 includes, in addition to the second unit 32, a battery housing section 80 that houses a primary battery 85. That is, the third unit 33 includes a solar cell 40, a secondary battery 45, a communication section 70, and the battery housing section 80. The battery housing section 80 is disposed outside the upper cover 35 and the lower cover 36. The battery housing section 80 houses a so-called dry battery as the primary battery 85.

[0057] In the third unit 33, the control unit 60 can switch between the power supplied from the secondary battery 45 and the power supplied from the primary battery 85 to cause the light-emitting unit 20 to emit light. In other words, the light-emitting unit 20 disposed in the main body 2 to which the third unit 33 is attached emits light using the power supplied from the secondary battery 45 or the power supplied from the primary battery 85 housed in the battery housing unit 80.

[0058] The control unit 60, for example, acquires the voltage of the power supplied from the secondary battery 45 and the voltage of the power supplied from the primary battery 85 and measures the magnitude of these voltages. The control unit 60 switches the power source for power supplied to the light-emitting unit 20 between the secondary battery 45 and the primary battery 85 based on the voltage of the secondary battery 45. That is, the control unit 60 determines whether the voltage of the secondary battery 45 is equal to or higher than a predetermined threshold, and based on the determination result, selects either the secondary battery 45 or the primary battery 85 as the power source for power supplied to the light-emitting unit 20, and switches the power source to either the secondary battery 45 or the primary battery 85.

[0059] The display device 1 according to this embodiment includes the above-described configuration, and its operation will be described below. Fig. 14 is an explanatory diagram showing the display device 1 shown in Fig. 2 in a state where the legs 10 are open. Fig. 15 is an explanatory diagram showing the display device 1 shown in Fig. 3 in a state where the legs 10 are open. Figs. 14 and 15 illustrate the display device 1 in which the first unit 31 is attached to the main body 2 in a state where the legs 10 are open, as an example for explaining the state when the display device 1 is in use.

[0060] The display device 1 is used by being installed in any location, such as a location where it is desired to indicate that construction work is underway. When installing the display device 1, the leg 10 is pulled out and raised by rotating the leg 10 around the rotating part 12 in a direction away from the panel 3. This positions the closed side of the U-shaped shape of the leg 10 away from the panel 3.

[0061] In this state, the display device 1 is placed in a desired location with one end of the frame 4 in the shorter direction facing downward. As a result, the display device 1 is placed so that the closed end of the U-shape of the leg 10 and the portion of the frame 4 located on the underside are in contact with the ground. When using the display device 1, the solar unit 30 is attached to the unit mounting bracket 16 that is located on the upper side when the display device 1 is placed, of the two unit mounting brackets 16, and the unit mounting bracket 16 to which the solar unit 30 is attached is rotated upward. This positions the solar unit 30 above the frame 4. The display device 1 is installed in a desired location with the solar unit 30 positioned on the upper end side of the main body 2 in this way.

[0062] When using the display device 1, the legs 10 are raised in this manner and the display device 1 is placed in any position with the solar unit 30 positioned on the upper end side when the display device 1 is placed. When using the display device 1, after placing it in the desired position in this manner, or before placing it, the power switch located on the solar unit 30 is turned ON to make the display device 1 ready for use.

[0063] When the solar unit 30 is attached to the unit mounting bracket 16 located on the upper end side of the main body 2, the solar unit 30 is oriented with the upper cover 35 facing upward, and therefore, during the day, sunlight irradiating the solar unit 30 passes through the upper cover 35 and is irradiated onto the solar cell 40 arranged inside the solar unit 30. The solar cell 40 generates electricity using the sunlight irradiated in this way, and the electricity generated by the solar cell 40 is supplied to the secondary battery 45 via the control unit 60 and stored in the secondary battery 45.

[0064] Since the solar cell 40 is disposed in the solar unit 30 located on the upper side of the main body 2 when the display device 1 is in use, the solar cell 40 is disposed in a position where it is likely to be irradiated with sunlight directly or indirectly during the day. Therefore, the solar cell 40 can efficiently convert a large amount of light energy into electricity during the day, and the converted electricity can be stored in the secondary battery 45.

[0065] When causing the light-emitting unit 20 to emit light, the control unit 60 causes the light-emitting unit 20 to emit light by supplying the power stored in the secondary battery 45 to the light-emitting unit 20. The control unit 60 is also capable of switching the light-emitting state of the light-emitting unit 20 by controlling the power supplied to the light-emitting unit 20, and the light-emitting state of the light-emitting unit 20 is switched based on the illuminance around the display device 1 and the state of the power stored in the secondary battery 45.

[0066] The switching of the light-emitting state of the light-emitting unit 20 based on the illuminance around the display device 1 is performed by comparing the illuminance around the display device 1 with a preset threshold value for the illuminance, and determining whether the illuminance is equal to or less than the threshold value. The threshold value for the illuminance is set in advance and stored in a storage unit provided in the control unit 60.

[0067] The illuminance around the display device 1 is detected by the illuminance detection unit 55, which also functions as the solar cell 40. That is, the illuminance around the display device 1 is detected based on the magnitude of the electric power converted from light energy by the solar cell 40. When detecting the illuminance based on the magnitude of the electric power converted by the solar cell 40, for example, the relationship between the illuminance of light irradiated on the solar cell 40 and the voltage of the electric power converted from light energy by the solar cell 40 is determined in advance and stored in the memory unit of the control unit 60. The control unit 60 acquires the voltage of the electric power converted by the solar cell 40, measures the voltage, and compares the voltage of the electric power converted by the solar cell 40 with the relationship between illuminance and voltage stored in the memory unit of the control unit 60. In this way, the illuminance around the display device 1 can be determined.

[0068] Furthermore, the switching of the light-emitting state of the light-emitting unit 20 based on the state of power stored in the secondary battery 45 is performed by comparing the voltage of the secondary battery 45 with a preset threshold value for voltage and determining whether the voltage of the secondary battery 45 is equal to or lower than the threshold value. The control unit 60 acquires the voltage of the power supplied from the secondary battery 45 when causing the light-emitting unit 20 to emit light and measures the magnitude of the voltage. If the voltage of the secondary battery 45 is equal to or lower than the predetermined threshold value, the control unit 60 reduces the power supplied to the light-emitting unit 20 compared to the power supplied to the light-emitting unit 20 during normal light emission. In other words, when causing the light-emitting unit 20 to emit light, if the voltage of the secondary battery 45 is equal to or lower than the predetermined threshold value, the control unit 60 reduces the power consumption of the secondary battery 45 by causing the light-emitting unit 20 to emit light in power-saving mode, which is light emission at a lower brightness than normal light emission.

[0069] Furthermore, in the display device 1 of this embodiment, when the light emitting unit 20 is emitting light and the irradiated light detection unit 50 detects light irradiated onto the display device 1 from the direction in which the light emitting unit 20 irradiates light, the brightness of the light emitting unit 20 is made higher than the brightness during normal light emission for a predetermined period of time.

[0070] Specifically, in the display device 1, a threshold value for light received by the irradiated light detection unit 50 is set in advance and stored in a memory unit of the control unit 60. The control unit 60 compares the light received by the irradiated light detection unit 50 while the light-emitting unit 20 is emitting light with the threshold value set in advance for light received by the irradiated light detection unit 50, and if the light received by the irradiated light detection unit 50 is higher than the threshold value, the control unit 60 increases the power supplied to the light-emitting unit 20 to increase the luminance of the light-emitting unit 20. In other words, if the light received by the irradiated light detection unit 50 while the light-emitting unit 20 is emitting light is higher than the threshold value, the control unit 60 causes the light-emitting unit 20 to emit light at a high luminance, which is higher than the luminance during normal light emission.

[0071] In addition, in the display device 1, the time for increasing the brightness of the light-emitting unit 20 is set in advance and stored in the memory of the control unit 60, and when the preset time has elapsed while the brightness of the light-emitting unit 20 is increased, the control unit 60 returns the brightness of the light-emitting unit 20 to the brightness before it was increased.

[0072] The display device 1 installed in any location, such as a location where it is desired to indicate that construction work is underway, switches the light emission state of the light-emitting unit 20 based on the illuminance around the display device 1, the state of power stored in the secondary battery 45, and the light irradiated onto the display device 1 from the direction in which the light-emitting unit 20 irradiates light. Next, the transition of the light emission state of the light-emitting unit 20 in the display device 1 will be described.

[0073] FIG. 16 is a transition diagram of the light-emitting state of the light-emitting unit 20 of the display device 1. The display device 1 changes the luminance of the light-emitting unit 20 based on the ambient illuminance. During the day, the illuminance around the display device 1 is high, so the control unit 60 turns off the light-emitting unit 20 (ST1). That is, the control unit 60 compares the illuminance detected by the illuminance detection unit 55, which also functions as the solar cell 40, with an illuminance threshold value that is a threshold value set for the illuminance. If the illuminance detected by the illuminance detection unit 55 is equal to or greater than the illuminance threshold value, the control unit 60 turns off the light-emitting unit 20. The illuminance threshold value is set to determine whether the area around the display device 1 is dark. In this embodiment, the illuminance threshold value is set to 1000 lx. During the day, the illuminance around the display device 1 is high, so the illuminance around the display device 1 is equal to or greater than the illuminance threshold value, so the control unit 60 turns off the light-emitting unit 20.

[0074] During the day, the illuminance is high, and the sunlight makes it easy for vehicle drivers and pedestrians to see the display device 1. Therefore, during the day, vehicle drivers and pedestrians can easily recognize construction sites and the like indicated by the display unit 6 of the display device 1, and can pass by the vicinity of the location where the display device 1 is installed while paying attention to the construction sites and the like.

[0075] On the other hand, since the illuminance is high during the day, solar cell 40 converts a large amount of light energy into electricity and supplies it to secondary battery 45. As a result, while power is not consumed by light-emitting unit 20 during the day, a large amount of power is supplied from solar cell 40 to secondary battery 45, so that a large amount of power is stored in secondary battery 45 during the day.

[0076] If time passes with the light-emitting unit 20 turned off, and the illuminance around the display device 1 drops below the illuminance threshold value at night, the control unit 60 causes the light-emitting unit 20 to emit light normally (ST2). That is, if the illuminance detected by the illuminance detection unit 55, which also serves as the solar cell 40, falls below the illuminance threshold value, the control unit 60 causes the light-emitting unit 20 to emit light at the normal emission mode, which is the normal emission mode of the light-emitting unit 20.

[0077] That is, at night, the ambient illumination decreases, making it difficult for vehicle drivers and pedestrians to see the display device 1. For this reason, the display device 1 illuminates the light-emitting unit 20 so that the information shown on the display unit 6 can be seen by the vehicle driver or pedestrian. This allows the vehicle driver or pedestrian to recognize the information shown on the display unit 6 even at night by the light from the light-emitting unit 20, and by recognizing the construction sites, etc. shown on the display unit 6, they can pass by while paying attention to the construction sites, etc.

[0078] In this embodiment, the light emitting unit 20 emits light while being controlled to blink, thereby enabling the display device 1 to draw the attention of vehicle drivers and pedestrians to the display device 1 and to call attention to construction sites and the like.

[0079] Here, a vehicle traveling at night travels with its headlights on. Therefore, when a vehicle travels near the display device 1, light from the vehicle's headlights may be irradiated onto the display device 1. When light from the vehicle's headlights is irradiated onto the surface of the display device 1 on which the display unit 6 is disposed, the light from the light-emitting unit 20 on which the display unit 6 is disposed may be mixed with the light from the headlights reflected by the display device 1.

[0080] For example, when display device 1 is installed near a construction site ahead of a vehicle in the traveling direction, with the surface on which display unit 6 is located facing the vehicle, and the vehicle approaches display device 1 with its headlights on, light from the headlights is irradiated onto the surface of display device 1 on which display unit 6 is located. At night, light-emitting unit 20 emits light, but when light from the vehicle's headlights is irradiated onto the surface of display device 1 on which display unit 6 is located, display device 1 reflects the light from the headlights with the entire panel 3, and the light from light-emitting unit 20 may become mixed up with the light reflected by panel 3. When the light from light-emitting unit 20 becomes mixed up with the light from the headlights reflected by panel 3 of display device 1, it becomes difficult for the driver of the vehicle to recognize the light from light-emitting unit 20, and there is a risk that the driver of the vehicle may have difficulty recognizing the information displayed by display device 1 using the light from light-emitting unit 20 as well.

[0081] In contrast, in the display device 1 according to this embodiment, the irradiated light detection unit 50 is arranged in the solar unit 30, and the irradiated light detection unit 50 is arranged on the same side of the solar unit 30 as the side on which the light-emitting unit 20 arranged in the main body 2 is located. Therefore, when light from the vehicle headlights is irradiated onto the surface on which the display unit 6 of the display device 1 is located, the irradiated light detection unit 50 detects the light irradiated from the headlights. In other words, the irradiated light detection unit 50 detects the light from the vehicle headlights that is irradiated from the direction in which the light-emitting unit 20 arranged in the main body 2 irradiates light.

[0082] When the irradiated light detection unit 50 detects light irradiated from the direction in which the light emitting unit 20 irradiates light while the light emitting unit 20 is emitting light, the control unit 60 increases the luminance of the light emitting unit 20 to cause the light emitting unit 20 to emit light at a high luminance (ST3). That is, the control unit 60 compares the illuminance of the irradiated light detected by the irradiated light detection unit 50 with an irradiated light threshold which is a threshold set for the illuminance of the irradiated light, and when the illuminance of the irradiated light detected by the irradiated light detection unit 50 is equal to or greater than the irradiated light threshold, the control unit 60 increases the luminance of the light emitting unit 20 above the luminance of normal light emission.

[0083] The irradiated light threshold is a threshold set to determine whether light from a vehicle headlight is irradiated onto the surface on which the light-emitting unit 20 of the display device 1 is disposed when it is dark around the display device 1, such as at night, and in this embodiment, the irradiated light threshold is set to 50 lx. If the illuminance of the irradiated light detected by the irradiated light detection unit 50 is equal to or greater than the irradiated light threshold, the control unit 60 determines that light from a vehicle headlight is irradiated onto the surface on which the light-emitting unit 20 of the display device 1 is disposed, and causes the light-emitting unit 20 to emit light at high brightness.

[0084] When light-emitting unit 20 emits light with high brightness, even when light from the vehicle's headlights is reflected by panel 3, the light from light-emitting unit 20 can be made brighter than the light reflected by panel 3, making the light from light-emitting unit 20 more noticeable to the driver of the vehicle. This allows the driver of a vehicle traveling at night to recognize the light from light-emitting unit 20 in display device 1, where light from the headlights is reflected by panel 3, and to recognize construction sites and the like indicated by display unit 6.

[0085] Since the irradiated light detection unit 50 is covered with the lower cover 36 made of a transparent member, light irradiated from the vehicle headlights other than light irradiated from the front of the irradiated light detection unit 50 can also be detected by the irradiated light detection unit 50 as the light passes through the lower cover 36. Therefore, the irradiated light detection unit 50 can detect light irradiated from the vehicle headlights that is irradiated from an oblique direction toward the irradiated light detection unit 50, and the control unit 60 causes the light emitting unit 20 to emit light with high brightness based not only on light irradiated from the vehicle headlights that is irradiated from the front toward the irradiated light detection unit 50 but also on light irradiated from the vehicle headlights that is irradiated from an oblique direction.

[0086] Furthermore, the solar cell 40 arranged in the solar unit 30 also serves as the eaves portion 38, so that the light irradiated from above onto the irradiated light detection portion 50 can be blocked by the eaves portion 38 in which the solar cell 40 is used. As a result, for example, by blocking light from streetlights and lighting fixtures installed on store signs that irradiate the display device 1 from above at night, the eaves portion 38 can prevent the irradiated light detection portion 50 from detecting this light as light irradiated from vehicle headlights.

[0087] After causing the light-emitting unit 20 to emit light at high brightness, the control unit 60 returns the brightness of the light-emitting unit 20 to normal light emission when a preset predetermined time has elapsed. In this embodiment, the predetermined time is set to 3 seconds and is stored in the memory unit of the control unit 60. Therefore, in this embodiment, the control unit 60 causes the light-emitting unit 20 to emit light at high brightness for only 3 seconds, and returns the brightness of the light-emitting unit 20 to normal when 3 seconds have elapsed since the light-emitting unit 20 emitted light at high brightness.

[0088] After the light-emitting unit 20 emits light at high brightness, the irradiated light detection unit 50 may newly detect irradiated light at or above the irradiated light threshold before a predetermined time has elapsed. For example, when multiple vehicles are traveling at a relatively short inter-vehicle distance, the irradiated light detection unit 50 may detect that the illuminance of light emitted from the headlights of one vehicle is equal to or above the irradiated light threshold, causing the light-emitting unit 20 to emit light at high brightness. However, before three seconds have elapsed, the irradiated light detection unit 50 may detect that the illuminance of light emitted from the headlights of a following vehicle is equal to or above the irradiated light threshold. In such a case, when a predetermined time, for example, three seconds, has elapsed since the last time the irradiated light detection unit 50 detected that the irradiated light was equal to or above the irradiated light threshold, the luminance of the light-emitting unit 20 is returned to the luminance of normal light emission.

[0089] In the display device 1, when the illuminance around the display device 1 is equal to or lower than the illuminance threshold value, the control unit 60 causes the light-emitting unit 20 to emit light normally or at high brightness, and the light-emitting unit 20 emits light using power supplied from the secondary battery 45. The secondary battery 45 stores power converted from light energy by the solar cell 40 and supplies the stored power to the light-emitting unit 20, but when there is little light irradiating the solar cell 40, such as at night, the power converted by the solar cell 40 also decreases. In this case, the secondary battery 45 continues to supply power to the light-emitting unit 20 without storing any new power, and the amount of power stored in the secondary battery 45 gradually decreases.

[0090] If the amount of power stored in the secondary battery 45 decreases and the secondary battery 45 is no longer able to supply the light-emitting unit 20 with the power necessary to illuminate the light-emitting unit 20, the light-emitting unit 20 will no longer be able to emit light. Therefore, when controlling the light-emitting unit 20 to emit light, the control unit 60 also determines whether the voltage of the power stored in the secondary battery 45 is equal to or higher than a predetermined threshold. That is, when causing the light-emitting unit 20 to emit light, the control unit 60 determines whether the voltage of the secondary battery 45 is equal to or lower than a predetermined voltage threshold, and if the voltage of the secondary battery 45 is equal to or lower than the voltage threshold, causes the light-emitting unit 20 to emit light in a power-saving manner (ST4). Note that the voltage threshold, which is the predetermined threshold set for the voltage of the secondary battery 45, is set to a value that allows it to be determined that the amount of power stored in the secondary battery 45 has decreased, relative to the voltage when the secondary battery 45 is fully charged. Therefore, the voltage threshold is set, for example, to a value that is arbitrarily small relative to the nominal voltage of the secondary battery 45.

[0091] If the voltage of the secondary battery 45 when causing the light-emitting unit 20 to emit light is equal to or lower than the voltage threshold, the control unit 60 reduces the power supplied from the secondary battery 45 to the light-emitting unit 20 to less than the power supplied during normal light emission. As a result, although the brightness of the light-emitting unit 20 becomes lower than during normal light emission, the power consumption is reduced, and therefore it is possible to prevent a decrease in the amount of stored power in the secondary battery 45 due to causing the light-emitting unit 20 to emit light.

[0092] Even in the power-saving light emission mode, the light-emitting unit 20 still emits light, albeit at a low brightness, so that in conditions where the ambient illumination is low, such as at night, vehicle drivers and pedestrians can more easily recognize the display unit 6 of the display device 1 than when the light-emitting unit 20 is turned off. This allows vehicle drivers and pedestrians to recognize construction sites, etc. where the display device 1 is installed, by the light from the light-emitting unit 20 of the display device 1, and they can pass by while paying attention to the construction sites, etc.

[0093] As time passes while the light-emitting unit 20 is emitting normal light (ST2) or power-saving light (ST4), if it becomes daytime and the illuminance around the display device 1 becomes higher than the illuminance threshold, the control unit 60 turns off the light-emitting unit 20 (ST1). When the illuminance around the display device 1 becomes higher than the illuminance threshold, the display unit 6 arranged on the main body 2 of the display device 1 can be clearly seen by sunlight even if the light-emitting unit 20 is turned off. This allows vehicle drivers and pedestrians to easily recognize construction sites, etc. indicated by the display unit 6 of the display device 1, and they can pass by the location where the display device 1 is installed while paying attention to the construction sites, etc.

[0094] Furthermore, when the illuminance around the display device 1 becomes higher than the illuminance threshold, a lot of light is irradiated onto the solar cell 40, so the solar cell 40 can convert a lot of light energy into electricity and store the converted electricity in the secondary battery 45. This allows a lot of electricity to be stored in the secondary battery 45 during the day.

[0095] Next, communication control between display devices 1 when the second unit 32 or the third unit 33 is attached to the main body 2 will be described. Both the second unit 32 and the third unit 33 have a communication unit 70, so a display device 1 with the second unit 32 or the third unit 33 attached to the main body 2 can communicate with other display devices 1. In this embodiment, communication between display devices 1 with the second unit 32 or the third unit 33 attached is performed, thereby synchronizing the blinking of the light-emitting units 20 between the display devices 1.

[0096] 17 is an explanatory diagram for creating a synchronization group G for synchronizing the light emission of the light-emitting units 20 among display devices 1. The synchronization of the light emission of the light-emitting units 20 among display devices 1 is achieved by wirelessly communicating between the communication units 70 of each display device 1 to create a synchronization group G, which is a group for synchronizing the display devices 1 with each other, and the light emission is synchronized among the multiple display devices 1 that make up the synchronization group G. To explain how the synchronization group G is created, for example, after the display device 1 is powered on, the communication unit 70 of each display device 1 equipped with the second unit 32 or the third unit 33 transmits a signal from the communication unit 70 to the other display devices 1 when the light emission of the light-emitting units 20 is in an emitting state, to synchronize the blinking patterns among the display devices 1.

[0097] Among the multiple display devices 1, the display device 1 that first transmits a signal from the communication unit 70 for synchronizing the blinking patterns of the display devices 1 operates as the parent device 1a among the multiple display devices 1. The display device 1 that is arranged within a distance that can receive the signal transmitted by wireless communication from the parent device 1a and receives the signal for synchronization transmitted from the parent device 1a operates as the child device 1b.

[0098] The slave device 1b receives a signal from the master device 1a via wireless communication at its communication unit 70, and the communication unit 70 of the slave device 1b further transmits a signal for synchronization to another display device 1. A display device 1 that is arranged within a distance range where it can receive the signal transmitted by wireless communication from the slave device 1b and receives the signal for synchronization transmitted from the slave device 1b at its communication unit 70 also operates as the slave device 1b and transmits a signal for synchronization from its communication unit 70.

[0099] 17, a synchronization signal transmitted from a display device 1 operating as a master device 1a is received by a display device 1 located close to the master device 1a. The display device 1 that receives the signal transmitted from the master device 1a operates as a first slave device 1b1, which is the first slave device 1b in the direction of signal flow between the slave devices 1b, and transmits a synchronization signal to the other display devices 1.

[0100] The signal transmitted from the first slave device 1b1 is received by a display device 1 located close to the first slave device 1b1. The display device 1 that receives the signal transmitted from the first slave device 1b1 operates as a second slave device 1b2, which is the second slave device 1b in the direction of signal flow between the slave devices 1b, and transmits a signal for synchronization to the other display devices 1.

[0101] The signal transmitted from the second handset 1b2 is received by a display device 1 located close to the second handset 1b2. The display device 1 that receives the signal transmitted from the second handset 1b2 operates as a third handset 1b3, which is the third handset 1b in the direction of signal flow between the handset 1b, and transmits a signal for synchronization to the other display devices 1.

[0102] After the power is turned on, when the light-emitting units 20 of the display devices 1 that can communicate with each other are in an emitting state, the display devices 1 perform these operations and send and receive signals for synchronization via the communication units 70, thereby creating a synchronization group G having one master device 1a and multiple slave devices 1b. By creating a synchronization group G with multiple display devices 1 in this manner, the display devices 1 can synchronize the blinking of the light-emitting units 20 among the display devices 1 that make up the synchronization group G when the light-emitting units 20 of each display device 1 are lit. In other words, the control unit 60 of each display device 1 communicates with the control units 60 of the other display devices 1 via the communication units 70, and synchronizes the blinking patterns between the communicating display devices 1, thereby enabling the timing of turning on and off the light-emitting units 20 to be synchronized among the communicating display devices 1, thereby controlling the blinking of the light-emitting units 20.

[0103] Here, each display device 1 switches the light-emitting unit 20 on and off depending on the illuminance detected by the illuminance detection unit 55, and when the illuminance detected by the illuminance detection unit 55 becomes equal to or lower than the illuminance threshold, the light-emitting unit 20 of each display device 1 emits light. Therefore, the blinking of the light-emitting unit 20 is synchronized when the illuminance detected by the illuminance detection unit 55 becomes equal to or lower than the illuminance threshold and the light-emitting unit 20 of each display device 1 emits light in normal emission, high-brightness emission, or power-saving emission.

[0104] Next, blinking control when the blinking of the light-emitting unit 20 is synchronized among the plurality of display devices 1 that make up the synchronization group G will be described. Fig. 18 is an explanatory diagram of when the blinking patterns are synchronized to make the light-emitting unit 20 blink. When the illuminance detected by the illuminance detection unit 55 becomes equal to or lower than the illuminance threshold value and each display device 1 that makes up the synchronization group G makes the light-emitting unit 20 emit light, each slave device 1b blinks its own light-emitting unit 20 in synchronization with the blinking pattern of the master device 1a.

[0105] Specifically, the control unit 60 of the master unit 1a controls the blinking of the light-emitting unit 20 in accordance with a preset blinking pattern, and transmits a signal regarding the blinking timing from the communication unit 70. That is, in order to synchronize the blinking patterns with the other display devices 1, the master unit 1a blinks its own light-emitting unit 20 in accordance with the blinking pattern, and transmits to the other display devices 1 a signal regarding the timing of turning on and off the light-emitting unit 20 when blinking its own light-emitting unit 20. The signal regarding the blinking timing transmitted from the master unit 1a is transmitted sequentially to the multiple slave units 1b that constitute the synchronization group G together with the master unit 1a, and is received by each slave unit 1b.

[0106] For example, a signal regarding the blinking timing transmitted from the master unit 1a is received by the first slave unit 1b1, which is located close to the master unit 1a. The control unit 60 of the first slave unit 1b1, which receives the signal from the master unit 1a via the communication unit 70, blinks the light-emitting unit 20 in accordance with the blinking timing transmitted from the master unit 1a, and transmits the signal regarding the blinking timing transmitted from the master unit 1a to the other display devices 1 via the communication unit 70.

[0107] The signal from the first handset 1b1 is received by the second handset 1b2, which is located close to the first handset 1b1. The control unit 60 of the second handset 1b2 causes the light-emitting unit 20 to blink in accordance with the blinking timing transmitted from the first handset 1b1, and transmits a signal regarding the blinking timing transmitted from the first handset 1b1 to the other display devices 1 from the communication unit 70.

[0108] The signal from the second handset 1b2 is received by the third handset 1b3, which is located close to the second handset 1b2. The control unit 60 of the third handset 1b3 causes the light-emitting unit 20 to blink in accordance with the blinking timing transmitted from the second handset 1b2, and transmits a signal regarding the blinking timing transmitted from the second handset 1b2 to the other display devices 1 from the communication unit 70.

[0109] The multiple display devices 1 that make up the synchronization group G can send and receive signals regarding the blinking timing between the display devices 1 in this manner, and blink the light-emitting units 20 according to the blinking pattern, thereby making it possible for the multiple display devices 1 that make up the synchronization group G to blink the light-emitting units 20 at the same timing as each other.

[0110] As a result, light from the light-emitting units 20 of the multiple display devices 1, which flash in sync, enters the eyes of the driver of a vehicle traveling near the construction site where the display device 1 is installed, making it easier for the driver to become aware of the display device 1. This makes it easier for the driver of the vehicle to become aware of the construction site where the multiple display devices 1 are installed, and makes it easier for the driver to pay attention to the construction site on the road indicated by the display device 1.

[0111] The multiple display devices 1 that make up the synchronization group G synchronize the blinking of the light-emitting units 20 while communicating wirelessly among themselves, but the brightness of the light-emitting units 20 is controlled individually for each display device 1, rather than synchronized among the display devices 1. In other words, high-brightness light emission when the irradiated light detection unit 50 detects irradiated light, and power-saving light emission when the voltage of the secondary battery 45 drops below the voltage threshold, are controlled individually for each display device 1.

[0112] Even when some of the display devices 1 constituting the synchronization group G cause the light-emitting units 20 to emit light with high brightness or low-power emission, and other display devices 1 cause the light-emitting units 20 to emit light with normal emission, the blinking timing of the light-emitting units 20 is synchronized. For this reason, for example, when some of the display devices 1 cause the light-emitting units 20 to emit light with high brightness emission, and other display devices 1 cause the light-emitting units 20 to emit light with normal emission, the blinking control is performed by synchronizing the blinking of the light-emitting units 20 with a mixture of high brightness emission and normal emission in the multiple display devices 1 constituting the synchronization group G.

[0113] Furthermore, a synchronization group G created by multiple display devices 1 communicating with each other synchronizes the blinking of the light-emitting units 20 among the display devices 1 that make up the synchronization group G to control the blinking of the light-emitting units 20, and then is dissolved when the light-emitting units 20 are turned off because the illuminance detected by the illuminance detection unit 55 becomes higher than the illuminance threshold, and after the light-emitting units 20 are turned on again, the synchronization group G is created again. In other words, when the light-emitting units 20 are turned off, each display device 1 controls them individually without creating a synchronization group G, and each time the illuminance detected by the illuminance detection unit 55 becomes equal to or lower than the illuminance threshold and the light-emitting units 20 are turned on, a synchronization group G is created by the multiple display devices 1, and control is performed to synchronize the blinking of the light-emitting units 20.

[0114] Furthermore, when a new display device 1 is added to a synchronization group G made up of multiple display devices 1, the added display device 1 controls its blinking by adjusting its own blinking timing to that of the other display devices 1 that make up the same synchronization group G. For example, after a synchronization group G is created with multiple display devices 1, if another display device 1 is newly placed in a position where it can communicate wirelessly with any of the display devices 1, the newly placed display device 1 is added to the synchronization group G as a new slave device 1b. The display device 1 added to the synchronization group G as the new slave device 1b communicates with display devices 1 in the same synchronization group G, thereby adjusting the blinking timing of the light-emitting unit 20 when controlling its blinking to that of the higher-ranking slave device 1b in the synchronization group G.

[0115] When a new display device 1 or a new slave device 1b is added to a synchronization group G, the order of signal flow directions when communication between slave devices 1b may be changed depending on the location of the new display device 1 relative to the multiple display devices 1 constituting the synchronization group G. For example, when a new display device 1 is placed between a first slave device 1b1 and a second slave device 1b2, the newly placed display device 1 may be designated as the second slave device 1b2, and the previous second slave device 1b2 may be designated as the third slave device 1b3 that receives signals transmitted from the newly placed display device 1. When a new display device 1 is added to a synchronization group G, it is preferable to set the order of signals for synchronizing blinking timing between the display devices 1 so that, while communicating with each other, signals are transmitted and received between display devices 1 that are positioned as close as possible depending on the locations of the multiple display devices 1 including the new display device 1.

[0116] Next, we will explain how to switch the power source that supplies power to the light-emitting unit 20 when the third unit 33 is attached to the main body 2. The third unit 33 has a battery housing 80 that houses a primary battery 85, and the control unit 60 of the third unit 33 can switch the power supplied to the light-emitting unit 20 between power supplied from the secondary battery 45 and power supplied from the primary battery 85 housed in the battery housing 80.

[0117] The power supplied to the light-emitting unit 20 is switched based on the voltage of the secondary battery 45. That is, the control unit 60 of the third unit 33 stores a voltage threshold, which is a threshold set for the voltage of the secondary battery 45, in a memory unit of the control unit 60, and switches the power supplied to the light-emitting unit 20 by comparing the voltage of the secondary battery 45 with the voltage threshold. That is, in the third unit 33, when the light-emitting unit 20 is being caused to emit light normally using power supplied from the secondary battery 45, if the voltage of the secondary battery 45 falls below the voltage threshold, the power supplied to the light-emitting unit 20 is first switched to power from the primary battery 85. As a result, the light-emitting unit 20 is caused to emit light normally using power supplied from the primary battery 85.

[0118] When the voltage of the primary battery 85 drops below a predetermined threshold while the light-emitting unit 20 is emitting normal light using power supplied from the primary battery 85, the light-emitting unit 20 emits light in a power-saving manner. When the light-emitting unit 20 emits light in a power-saving manner, it is preferable that the power source for first supplying power to the light-emitting unit 20 is the primary battery 85, and when the voltage of the primary battery 85 drops further, power is supplied to the light-emitting unit 20 from the secondary battery 45. This allows the light-emitting unit 20 to emit light for as long as possible, thereby alerting vehicle drivers and pedestrians to construction sites and the like.

[0119] In the display device 1 according to this embodiment, by attaching the solar units 30 having different configurations to the main body 2, different functions can be realized by replacing the solar units 30.

[0120] The display device 1 according to the above embodiment includes an irradiated light detection unit 50 that detects light irradiated from the direction in which the light-emitting unit 20 emits light. When the irradiated light detection unit 50 detects light irradiated from the direction in which the light-emitting unit 20 emits light while the light-emitting unit 20 is emitting light, the control unit 60 increases the luminance of the light-emitting unit 20. Therefore, even when light from a vehicle's headlights is irradiated onto the surface of the main body 2 on which the light-emitting unit 20 is disposed and the irradiated light is reflected by the main body 2, increasing the luminance of the light from the light-emitting unit 20 makes the light from the light-emitting unit 20 more noticeable compared to the light reflected by the main body 2. This makes it possible to use light from the light-emitting unit 20 to alert the driver of a construction site or the like in a dark environment around the display device 1, such as at night, making the light from the light-emitting unit 20 more visible to a driver traveling with their headlights on. As a result, visibility when the light-emitting unit 20 is emitting light can be improved.

[0121] Furthermore, since the control unit 60 increases the brightness of the light-emitting unit 20 and then returns the brightness of the light-emitting unit 20 to its original value after a predetermined time has elapsed, it is possible to suppress an increase in power consumption due to increasing the brightness of the light-emitting unit 20. This makes it possible to prevent the power of the power supply for the light-emitting unit 20 from decreasing prematurely, and when the light-emitting unit 20 is made to emit light, it is possible to make the light-emitting unit 20 emit light for a long period of time. As a result, it is possible to draw attention with light from the light-emitting unit 20 for a long period of time.

[0122] Furthermore, the display device 1 includes an illuminance detection unit 55, which causes the light-emitting unit 20 to emit light when the illuminance detected by the illuminance detection unit 55 is equal to or lower than a predetermined threshold, and turns off the light-emitting unit 20 when the illuminance detected by the illuminance detection unit 55 is higher than the threshold. This allows the light-emitting unit 20 to emit light only when the surroundings of the display device 1 are dark and the display device 1 is difficult to see. This reduces the amount of power consumed by illuminating the light-emitting unit 20, and prevents the power of the power supply for the light-emitting unit 20 from decreasing prematurely. This allows the light-emitting unit 20 to emit light for a longer period of time, and prevents the light-emitting unit 20 from becoming unable to emit light due to a decrease in the power supply. As a result, the light from the light-emitting unit 20 can be used to alert the user for a longer period of time.

[0123] Furthermore, the display device 1 includes a solar cell 40 and a secondary battery 45 that stores the power converted by the solar cell 40. The light-emitting unit 20 emits light using power supplied from the secondary battery 45. Therefore, the power required to emit light from sunlight irradiating the display device 1 can be secured. This eliminates the need to frequently replace batteries when the battery power runs out, for example, when only dry batteries are used as the power source for the light-emitting unit 20, and prevents the user from noticing that the battery power has run out and being unable to emit light from the light-emitting unit 20. Furthermore, it eliminates the need to connect the display device 1 to an external power source each time the display device 1 is used, for example, when an external power source is used as the power source for the light-emitting unit 20. As a result, the light-emitting unit 20 can be easily illuminated for a long period of time, and the user can easily alert the user for a long period of time.

[0124] Furthermore, the display device 1 includes a communication unit 70 that wirelessly transmits and receives signals from the control unit 60, and the control unit 60 synchronizes the blinking of the light-emitting units 20 between display devices 1 that communicate via the communication unit 70 to control the blinking of the light-emitting units 20, making it easier for vehicle drivers and pedestrians to notice the light from the light-emitting units 20. As a result, the light from the light-emitting units 20 of multiple display devices 1 that blink in sync can draw the attention of vehicle drivers and pedestrians to construction sites where the display devices 1 are installed. As a result, attention can be more reliably drawn.

[0125] Furthermore, the display device 1 includes a battery housing 80, and the light-emitting unit 20 emits light using power supplied from the secondary battery 45 or power supplied from the primary battery 85 housed in the battery housing 80. This allows the light-emitting unit 20 to emit light for a long period of time using the power from the secondary battery 45 and the power from the primary battery 85. This prevents the light-emitting unit 20 from being unable to emit light if the power from the power source runs out when a single power source is used to light up the light-emitting unit 20, and allows the light-emitting unit 20 to emit light for a long period of time. As a result, the light from the light-emitting unit 20 can be used to call attention for a long period of time.

[0126] Furthermore, the display device 1 includes a first unit 31, a second unit 32, and a third unit 33, each of which has a different configuration. The first unit 31, the second unit 32, and the third unit 33 are interchangeably attached to the main body 2, so that different functions can be realized by exchanging the first unit 31, the second unit 32, and the third unit 33. This allows display devices 1 with different functions to be manufactured using a common main body 2, thereby reducing manufacturing costs. Furthermore, since display devices 1 with different functions can be prepared using a common main body 2, storage space for the display devices 1 can be saved. Furthermore, if a different function is required for the display device 1 currently in use, the required function can be achieved by exchanging the first unit 31, the second unit 32, or the third unit 33. As a result, the manufacturing cost of the display device 1 can be reduced, storage space for the display device 1 can be saved, and usability of the display device 1 can be improved.

[0127] Furthermore, since the illuminating light detecting unit 50 is provided with the canopy portion 38 that blocks light irradiated from above, it is possible to prevent the illuminating light detecting unit 50 from erroneously detecting light other than light irradiated from the vehicle headlamp. This makes it possible to prevent the light-emitting unit 20 from being made to emit light by increasing the brightness even when light irradiated from the vehicle headlamp is not irradiated onto the display device 1. This makes it possible to prevent the brightness of the light-emitting unit 20 from being increased at an unnecessary time, and to prevent an increase in power consumption due to increasing the brightness of the light-emitting unit 20 at an unnecessary time, which in turn makes it impossible for the light-emitting unit 20 to emit light due to the power supply of the light-emitting unit 20 running out early. As a result, it is possible for the light-emitting unit 20 to emit light for a long period of time, and it is possible to alert people with light from the light-emitting unit 20 for a long period of time.

[0128] Furthermore, because the lower cover 36 covering the irradiated light detection unit 50 is made of a transparent material, the irradiated light detection unit 50 can detect not only irradiated light irradiated from the front onto the irradiated light detection unit 50 but also irradiated light irradiated from an oblique direction onto the irradiated light detection unit 50 by transmitting the irradiated light through the lower cover 36. This allows the irradiated light detection unit 50 to detect not only irradiated light from the vehicle headlamp irradiating the irradiated light detection unit 50 from the front, but also irradiated light irradiated from an oblique direction onto the irradiated light detection unit 50, so the irradiated light detection unit 50 can more reliably detect light irradiated from the vehicle headlamp. Therefore, when light from the vehicle headlamp irradiates the surface of the main body 2 on which the light emitting unit 20 is disposed while the light emitting unit 20 is emitting light, the control unit 60 can more reliably increase the luminance of the light emitting unit 20. Therefore, even when light emitted from the vehicle headlamps is reflected by the main body 2, the light from the light-emitting unit 20 can be made more noticeable, and the light from the light-emitting unit 20 can be more easily and reliably seen by a driver of a vehicle traveling with the headlamps turned on. As a result, the visibility of the light-emitting unit 20 when it is emitting light can be more reliably improved.

[0129] [Variations] In the above-described embodiment, the first unit 31 includes the solar cell 40 and the secondary battery 45, the second unit 32 includes the solar cell 40, the secondary battery 45, and the communication unit 70, and the third unit 33 includes the solar cell 40, the secondary battery 45, the communication unit 70, and the battery housing 80, but the solar unit 30 may have a configuration other than these. For example, the solar unit 30 may have a configuration including the solar cell 40, the secondary battery 45, and the battery housing 80 without including the communication unit 70. The configuration of the solar unit 30 is not important as long as it includes the control unit 60 that controls the brightness of the light-emitting unit 20 and the irradiated light detection unit 50 that detects light irradiated from the direction in which the light-emitting unit 20 irradiates light.

[0130] In the above-described embodiment, the lower cover 36 is entirely made of a transparent material, but the lower cover 36 that covers the irradiated light detection unit 50 does not have to be entirely transparent. It is sufficient that at least a portion of the lower cover 36 that covers the irradiated light detection unit 50 is made of a transparent material.

[0131] Furthermore, in the above-described embodiment, the illuminance detection unit 55 that detects illuminance is also the solar cell 40, but the illuminance detection unit 55 may be a member separate from the solar cell 40. For example, the illuminance detection unit 55 may be an illuminance sensor that can detect the illuminance of received light. The illuminance detection unit 55 may be any means or configuration as long as it can detect the illuminance around the display device 1 and the detection result can be used to control switching between illuminating and extinguishing the light-emitting unit 20.

[0132] In the above-described embodiment, the secondary battery 45 is used as the power storage unit that stores the power converted by the solar cell 40, but the power storage unit may be something other than the secondary battery 45. For example, a capacitor may be used as the power storage unit.

[0133] Furthermore, in the above-described embodiment, the solar cell 40 is used as the eaves portion 38 that blocks light irradiated from above onto the irradiated light detection unit 50, but the eaves portion 38 may be formed from a material other than the solar cell 40. The eaves portion 38 may be formed, for example, on the upper cover 35 or the lower cover 36 from a dedicated member for the eaves portion 38, which is made of a colored member that blocks light.

[0134] In the above-described embodiment, the illuminance threshold used to determine whether to cause the light-emitting unit 20 to emit light based on the illuminance around the display device 1 is set to 1000 lx, but the illuminance threshold may be a value other than this. Similarly, the irradiation light threshold used to determine whether to cause the light-emitting unit 20 to emit light at high brightness is set to 50 lx, but the irradiation light threshold may be a value other than this.

[0135] In the above-described embodiment, the illuminance threshold when the ambient illuminance decreases, such as when the daytime turns to nighttime, is the same as the illuminance threshold when the ambient illuminance increases, such as when the nighttime turns to daytime. However, the illuminance threshold value may be different depending on the direction of change in the ambient illuminance. That is, the illuminance threshold used to determine whether to switch the light-emitting unit 20 from its off state to normal light emission may be different from the illuminance threshold used to determine whether to switch from normal light emission to off. In this way, by varying the illuminance threshold value depending on the direction of change in the ambient illuminance of the display device 1, i.e., the direction of switching the light-emitting state of the light-emitting unit 20, frequent switching of the light-emitting state of the light-emitting unit 20 due to slight changes in illuminance can be suppressed when the ambient illuminance of the display device 1 is close to the illuminance at which the light-emitting state of the light-emitting unit 20 switches.

[0136] Furthermore, although the display device 1 according to the above-described embodiment has been described using a display device 1 having an arrow-shaped display unit 6, the display device 1 may be formed in other forms. For example, the display device 1 may display other figures or arbitrary characters when the light-emitting unit 20 is lit. Even in the case of a display device that displays figures or characters other than an arrow when the light-emitting unit 20 is lit, it is possible to alert pedestrians and vehicle drivers who view the display device 1 to construction sites, etc., and to effectively convey arbitrary information. [Explanation of symbols]

[0137] 1 Display device 2 Main body 3 Panels 4 Frame 6 Display section 10 Legs 12 Rotating part 16 Unit mounting bracket 17 Mounting material 18 Shaft member 20 Light-emitting part 30 solar units 31 Unit 1 32 Unit 2 33 Unit 3 35 Upper cover 36 Lower cover 36a Recess 38 Eaves 40 Solar Cells 45 Secondary battery 50 Irradiation light detection unit 55 Illuminance detection unit 60 Control Unit 70 Communications Department 71 Antenna 72 Communication control section 80 Battery compartment 85 Primary battery

Claims

1. a self-luminous light-emitting part; a main body portion in which the light emitting portion is disposed; a control unit that controls the brightness of the light-emitting unit; an irradiation light detection unit that detects light irradiated from the direction in which the light emitting unit irradiates light; Equipped with The control unit increases the brightness of the light-emitting unit when the light-emitting unit is emitting light from the direction in which the light-emitting unit emits light, using the irradiated light detection unit.

2. The display device according to claim 1 , wherein the control unit increases the luminance of the light-emitting unit and then returns the luminance of the light-emitting unit to its original value after a predetermined time has elapsed.

3. An illuminance detection unit is provided to detect the illuminance of the surroundings, 3. The display device according to claim 1, wherein the control unit causes the light-emitting unit to emit light when the illuminance detected by the illuminance detection unit is equal to or lower than a predetermined threshold, and turns off the light-emitting unit when the illuminance detected by the illuminance detection unit is higher than the threshold.

4. A solar cell that converts light energy into electricity; a power storage unit that stores the power converted by the solar cell; Equipped with The display device according to claim 1 , wherein the light-emitting portion emits light using power supplied from the power storage portion.

5. a communication unit that wirelessly transmits and receives signals from the control unit, the control unit controls the blinking of the light emitting unit, The display device according to claim 4 , wherein the control unit communicates with the control unit of another display device via the communication unit, and performs the blinking control by synchronizing the blinking of the light-emitting unit between the display devices that communicate with each other.

6. a battery housing portion for housing a primary battery; The display device according to claim 5 , wherein the light emitting section emits light using power supplied from the power storage section or power supplied from the primary battery housed in the battery housing section.

7. a first unit including the solar cell and the power storage unit; a second unit including the solar cell, the power storage unit, and the communication unit; a third unit including the solar cell, the power storage unit, and the battery housing unit; and The display device according to claim 6 , wherein the first unit, the second unit, and the third unit are each detachable from the main body and are each replaceably attached to the main body.

8. The display device according to claim 1 , further comprising a canopy that blocks light irradiated onto the irradiation light detection section from above.

9. 3. The display device according to claim 1, further comprising a cover that covers the irradiated light detection unit, and at least a part of the cover is made of a transparent material.

Images