JP6712531B2 - Display device and snow prevention method thereof - Google Patents

Description

The present invention relates to a display device and a snow accretion prevention method thereof.

A display (marking) device provided with a snowfall sensor is known (for example, Patent Documents 1 and 2). In Patent Documents 1 and 2, snow is prevented and visibility is ensured by driving a blower or starting power supply to a thermal element when a snow sensor detects snow. There is.

JP, 2002-38429, A JP, 2016-126151, A

However, the state in which the snowfall sensor detects snowfall does not necessarily mean that snowfall is likely to occur on the display surface. This is because the snowfall sensor detects snowfall from above, and snowfall from above is unlikely to land on the display surface installed almost vertically. On the contrary, even if the amount of snow is small, the possibility of snow accretion increases if the snow is blown perpendicularly to the display surface. Therefore, if power is supplied to the blower or the heating element based on the detection result of the snowfall sensor as in Patent Documents 1 and 2, power will be consumed unnecessarily.
In addition, in Patent Document 1, it is proposed that an anemometer and an anemoscope be provided in addition to the snowfall sensor, and that the blower ejection amount be adjusted based on the measurement results of the anemometer and the anemoscope. Further, in Patent Document 2, it is proposed to increase the amount of electric power supplied to the heating element when a signal indicating that there is a large amount of airflow or that there is a vertical headwind to the display device is output from the outside air detection sensor. ing. As described above, when the wind speed and the wind direction are taken into consideration, it is possible to supply power to the blower and the heat generating element in a state where snow is easily accumulated on the display surface. However, when the display device is provided with the anemometer or the wind vane, the device becomes complicated, and the manufacturing cost increases and the maintenance load increases.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of reducing snow accretion on a display surface with a small amount of electric power with a simple device configuration.

In order to achieve the above-mentioned object, the display device of the present invention includes a display surface, a heater for heating the display surface, and a snowfall sensor including a snow detection section for detecting the passage of snow from above with respect to the snow detection section. A horizontal snow sensor formed by arranging so as to block the passing snow, and a control unit that controls the amount of heat generated by the heater based on the snow detection result of the horizontal snow sensor.

In the configuration of the present invention described above, by disposing the snowfall sensor so as to block the snow passing from above with respect to the snow detection unit, it is difficult to detect snowfall from above, and the snow detection unit enters from the horizontal direction. It is possible to detect snow that falls. A snowfall sensor can detect snow that blows at an angle close to a vertical direction to the display surface, that is, snow that easily lands on the display surface, and the amount of heat generated by the heater can be effectively suppressed. Further, a conventional snowfall sensor may be arranged so as to block snow passing from above, and it is not necessary to provide an airflow meter or anemometer. That is, with a simple device configuration, snow accretion on the display surface can be reduced with a small amount of electric power.

1A is a front view of the display device, FIGS. 1B and 1C are side views of the display device, and FIG. 1D is an enlarged view of the display device. It is a perspective view of a snowfall sensor. It is a block diagram of a display device. It is a flowchart of snow accretion prevention processing. 5A is a front view of the display device, and FIG. 5B is an enlarged view of the display device.

Here, embodiments of the present invention will be described in the following order.
(1) First embodiment:
(2) Second embodiment:
(3) Other embodiments:

(1) First embodiment:
FIG. 1A is a front view of a display device 1 according to an embodiment of the present invention. The display device 1 of the present embodiment is a display device for an occupant of a vehicle traveling on a road to visually recognize various information. However, the display device 1 may be installed outdoors, and is not necessarily a road display device.

The display device 1 includes a pillar V, a lateral beam Y, a display plate B, and a snowfall sensor S. The column V is a columnar member whose lower end is fixed to the ground (hatching) so that the length direction is the vertical direction. The horizontal beam Y is a horizontal beam that connects the column V and the display board B. The display board B is cantilevered by a pillar V above the road. The display board B has a rectangular plate-shaped housing, and the display surface M is formed on one surface of the housing.

The direction in which the display surface M is formed is the front, and the display surface M is visually recognized by an occupant of a vehicle approaching from the front. On the display surface M, light-emitting elements such as LEDs are arranged in a dot matrix, and by individually controlling the lighting of the light-emitting elements, an image can be formed on the display surface M and various information can be displayed. it can.

1B and 1C are side views of the display device 1. Note that the pillar V is not shown in FIGS. 1B and 1C. In FIG. 1B, the display surface M is a surface in the vertical direction. However, as shown in FIG. The display surface M can be easily seen by an occupant of a vehicle traveling forward and downward. The inclination angle α can be set according to the height and size of the display surface M, the gradient of the road, and the like. In this embodiment, the height H of the display board B is 2200 mm, the width W is 3200 mm, and the depth D is 300 mm. Of course, the size of the display board B is not limited to the illustrated size.

As shown in FIGS. 1A to 1C, a snowfall sensor S is arranged below the display plate B. FIG. 1D is a side view showing an enlarged part where the snowfall sensor S is provided. The snowfall sensor S is arranged such that the upper end is joined to the front end of the bottom surface B1 of the display plate B. Therefore, the snowfall sensor S is arranged in front of the bisector X that bisects the bottom surface B1 of the display board B in the front and back. Further, the display surface M and the front surface of the snowfall sensor S are lined up on the same plane. The snowfall sensor S may be fixed to the bottom surface B1 of the display board B via a connecting member.

FIG. 2 is a perspective view of the snowfall sensor S. The snowfall sensor S has a substantially rectangular parallelepiped outer shape, and has a rectangular parallelepiped recess (snow detecting portion A) formed below. A light emitting portion S1 is provided on one side surface of the snow detecting portion A in the width direction, and a light receiving portion S2 is provided on the other side surface of the snow detecting portion A in the width direction. A light ray L (thick line arrow) emitted from the light emitting portion S1 penetrates the snow detection portion A in the width direction and is received by the light receiving portion S2. When snow passes through the optical path of the light ray L, the light ray L is not received by the light receiving section S2. Therefore, the amount of snow that has passed through the light beam L can be detected by constantly emitting light at the light emitting unit S1 and detecting the number of times the light beam L cannot be received by the light receiving unit S2. Any method may be used to detect the amount of snow, and for example, the total value of the lengths of periods in which light cannot be received may be detected as the amount of snow. The wavelength of the light ray L is not particularly limited, and the light ray L may be infrared light or visible light. The light beam L may be laser light. Further, instead of the light ray L, a sound wave or a radio wave other than the electromagnetic wave that can penetrate the snow detection unit A may be adopted.

In the present embodiment, the height h of the snowfall sensor S is 100 mm, the width w is 200 mm, and the depth d is 20 mm. The height h1 of the snow detecting portion A is 40 mm and the width w4 thereof is 140 mm. In the snowfall sensor S, the widths w2 and w3 of the left and right portions of the snow detection portion A are 30 mm, respectively.

In FIG. 1D, the snow detection unit A is indicated by hatching. As shown in FIG. 1D, the snowfall sensor S is arranged so that the snow detection unit A faces downward. Here, when the display board B is viewed from above in the vertical direction, the snowfall sensor S and the entire snow detection portion A are covered by the display board B and cannot be seen. Therefore, the snow falling in the vertical direction is blocked by the display plate B and does not reach the snow detecting section A. That is, the snowfall sensor S is arranged so as not to fulfill its original purpose of use, which is to detect snowfall from above.

On the other hand, the snow detecting portion A of the snowfall sensor S can pass snow that is blown obliquely and in the front-rear direction. Therefore, the snowfall sensor S can detect the amount of snow blown diagonally and in the front-back direction. Further, as shown in FIG. 1D, the snowfall sensor S is arranged in front of the bisector X that bisects the bottom surface B1 of the display plate B into front and rear. The bottom surface B1 may include a cross beam Y (FIG. 1A, FIG. 1B, FIG. 1C) that horizontally supports the back surface of the display panel B. Therefore, the snow trajectory KB (two-dot chain line) that can obliquely descend from the rear and pass the light ray L of the snow detection unit A without being blocked by the bottom surface B1 descends obliquely from the front and the light beam of the snow detection unit A. The angle is closer to horizontal than the snow trajectory KF (two-dot chain line) that can pass L. That is, except when the wind speed is extremely high, it is possible to prevent the snowfall sensor S from detecting snow blown from behind. Therefore, the amount of snow blown from the front can be more easily detected by the snowfall sensor S than the amount of snow blown from the rear. Further, since the display surface M and the front surface of the snowfall sensor S are aligned on the same plane, it is possible to prevent the snow falling obliquely from the front from being blocked by the bottom surface B1 of the display plate B.

As described above, the snowfall sensor S of this embodiment is mainly arranged so as to detect the amount of snow blown from the front. Here, the snowfall sensor S and the display plate B having a function of blocking snow passing from above with respect to the snow detection unit A constitute a lateral snow sensor Z (broken line) of the present invention. The position in the width direction where the snowfall sensor S is arranged below the display plate B is not particularly limited, and the snowfall sensor S may be arranged on the opposite side of the pillar V or the snowfall sensor S is arranged on the pillar V side. Alternatively, the snowfall sensor S may be arranged at the center in the width direction. Further, the columns V may be provided on both left and right sides of the display board B. Furthermore, in order to prevent the snow blown from behind from being detected more reliably, an eaves may be provided on the bottom surface B1 of the display board B to block the air flow from behind.

FIG. 3 is a block diagram of the display device 1. The display device 1 includes a display board B, a snowfall sensor S, a control unit 20, a temperature sensor 30, a power supply unit 40, and a power supply circuit 50. The control unit 20, the power supply unit 40, and the power supply circuit 50 may be provided inside the display board B, or may be provided inside a control box different from the display board B. The display board B includes a display unit 11 and a heater 12. The display unit 11 includes a plurality of light emitting elements such as LEDs arranged in a dot matrix, a driver circuit that generates a drive current for the plurality of light emitting elements, and the like. The heater 12 is a heating wire stretched around the plurality of light emitting elements arranged in a dot matrix on the display surface M so as to sew. By supplying electric power to the heater 12, the heater 12 generates Joule heat in an amount according to the magnitude of the electric power, and heats the display surface M. It should be noted that the heater 12 may be any element that generates heat, and is not necessarily a heating wire.

The temperature sensor 30 is a sensor that measures the outside air temperature. The power supply unit 40 is a power supply circuit that generates power supplied from an external power supply (commercial power supply) to each unit of the display device 1. The power supply unit 40 includes, for example, a DC circuit and a transformer circuit. The power supply circuit 50 is a circuit that generates a current to be supplied to the heater 12 based on a control signal from the control unit 20. The power supply circuit 50 generates a rectangular wave having a current value of High and Low as a current to be supplied to the heater 12, and based on a control signal from the control unit 20, a duty ratio that is a ratio of a period in which the current value is High. Adjust. The current value of High is constant, and the current value of Low is 0. Since the resistance value of the heater 12 is constant, the electric power supplied to the heater 12 can be adjusted by adjusting the duty ratio of the current supplied to the heater 12.

The control unit 20 is a computer including a CPU, a ROM, a RAM, etc., and a control program 21 recorded in the ROM is executed by the CPU. The control program 21 includes a display control module 21a and a heater control module 21b. With the function of the display control module 21a, the control unit 20 controls the lighting of the plurality of light emitting elements included in the display unit 11. Specifically, the control unit 20 generates a control signal to be output to the driver circuit of the display unit 11 based on the display image data recorded in the ROM by the function of the display control module 21a. The display image data may be acquired from an external device via a communication unit (not shown). The control unit 20 does not necessarily have to realize the functions of the present invention by using software, and may be an ASIC (application specific integrated circuit) or the like.

With the function of the heater control module 21b, the control unit 20 controls the heater 12 to execute snow accretion prevention processing, which is processing for preventing snow accretion on the display surface M. FIG. 4 is a flowchart of snow accretion prevention processing. The snow accretion prevention process may be executed only in the season when snow can fall (for example, the winter season).

First, the control unit 20 detects the temperature (step S100). That is, the control unit 20 acquires the outside air temperature detected by the temperature sensor 30. Next, the control unit 20 determines whether or not the temperature is below the threshold value (step S105). The threshold value may be, for example, an upper limit temperature (such as 2 degrees Celsius) at which snow accretion on the display surface M may occur.

When it is not determined that the temperature is equal to or lower than the threshold value (step S105: N), the control unit 20 turns off the heater 12 (step S110). That is, the control unit 20 outputs to the power supply circuit 50 a control signal for supplying the heater 12 with a current such that the duty ratio becomes zero. The method of turning off the heater 12 is not limited to one in which the duty ratio is set to 0. For example, the switch may be switched so as to cut off the electrical connection between the heater 12 and the power supply circuit 50.

On the other hand, when it is determined that the temperature is equal to or lower than the threshold value (step S105: Y), the control unit 20 acquires the amount of snow detected by the snowfall sensor S (step S115). Specifically, the control unit 20 acquires the detected amount of snow from the snowfall sensor S (lateral snow sensor Z) which is arranged so as to mainly detect the amount of snow blown from the front. That is, the control unit 20 acquires the detected amount of snow that is mainly blown from the front.

Next, the control unit 20 determines whether or not the detected amount of snow is the first determination value T1 or more (step S120). That is, the control unit 20 mainly determines whether or not the amount of snow blown from the front is the first determination value T1 or more. The first determination value T1 (for example, 0) is a predetermined value, and is a minute amount of snow that does not cause snowfall on the display surface M even if the temperature is below the threshold value.

When it is not determined that the detected amount of snow is the first determination value T1 or more (step S120: N), the control unit 20 turns off the heater 12 (step S110). That is, as in the case where the temperature is equal to or higher than the threshold value, the control unit 20 turns off the heater 12 on the assumption that snow cannot occur on the display surface M.

On the other hand, when it is determined that the detected amount of snow is not less than the first determination value T1 (step S120: Y), the control unit 20 determines whether the detected amount of snow is not less than the second determination value T2. Yes (step S125). Here, the second determination value T2 is a predetermined value and is a value larger than the first determination value T1.

When it is not determined that the detected amount of snow is equal to or greater than the second determination value T2 (step S125: N), the control unit 20 sets the power supplied to the heater 12 to G1×P (step S130). That is, when the amount of snow blown from the front is greater than or equal to the first determination value T1 but less than the second determination value T2, the control unit 20 turns on the heater 12 and sets its supply power to G1×P. Set. Here, P is the maximum power that can be supplied to the heater 12, and is the power when the duty ratio of the current supplied to the heater 12 is 100%. G1 (for example, 0.5) is a coefficient that takes a value between 0 and 1. The duty ratio of the current to be supplied to the heater 12 can be derived based on the supplied power, the resistance value of the heater 12, and the high current value.

On the other hand, when it is determined that the detected amount of snow is the second determination value T2 or more (step S125: Y), the control unit 20 determines whether the detected amount of snow is the third determination value T3 or more. Yes (step S135). Here, the third determination value T3 is a predetermined value and is a value larger than the first determination value T1 and the second determination value T2.

When it is not determined that the detected amount of snow is equal to or greater than the third determination value T3 (step S135: N), the control unit 20 sets the electric power supplied to the heater 12 to G2×P (step S140). That is, when the amount of snow blown from the front is equal to or greater than the second determination value T2 but is less than the third determination value T3, the control unit 20 turns on the heater 12 and sets its supply power to G2×P. Set. Here, G2 (for example, 0.75) is a coefficient that takes a value between 0 and 1 and is a coefficient that is larger than G1. The amount of heat generated by the heater 12 when the supplied power is set to G2×P (step S140) is larger than the amount of heat generated by the heater 12 when the supplied power is set to G1×P (step S130). ..

On the other hand, when it is determined that the detected amount of snow is not less than the third determination value T3 (step S135: Y), the control unit 20 sets the electric power supplied to the heater 12 to G3×P (step S145). That is, the control unit 20 turns on the heater 12 and sets the supplied power to G3×P when the amount of snow blown from the front is equal to or larger than the third determination value T3. Here, G3 (for example, 1) is a coefficient that takes a value between 0 and 1 and is a coefficient that is larger than G2. The amount of heat generated by the heater 12 when the supplied power is set to G3×P (step S145) is larger than the amount of heat generated by the heater 12 when the supplied power is set to G2×P (step S140). .. When the above process is completed, the control unit 20 waits for a certain period and then returns to step S100.

In the first embodiment described above, by disposing the snowfall sensor S so as to block the snow passing from above with respect to the snow detector A, it is difficult to detect snowfall from above, and the snow detector from the horizontal direction is detected. It is possible to detect snow that enters A. It is possible to detect the snow sprayed at an angle close to the display surface M at a vertical angle, that is, the snow that is likely to land on the display surface M by the snowfall sensor S, and effectively suppress the amount of heat generated by the heater 12. Further, the conventional snowfall sensor S may be arranged so as to block the snow passing from above, and it is not necessary to provide an airflow meter or anemometer. That is, with a simple device configuration, snow accretion on the display surface M can be reduced with less electric power.

Further, the control unit 20 increases the amount of heat generated by the heater 12 as the amount of snow detected by the horizontal snow sensor Z (snowfall sensor S) increases. As a result, the amount of heat generated by the heater 12 can be increased when the amount of snow detected by the side snow sensor Z is large and the amount of snow that is likely to land on the display surface M is large. On the contrary, when the amount of snow detected by the lateral snow sensor Z is small and the amount of snow that is likely to land on the display surface M is small, the amount of heat generated by the heater 12 can be reduced and power can be suppressed.

Further, when the temperature is equal to or lower than the threshold value, the control unit 20 heats the heater 12 based on the snow detection result of the side snow sensor Z. That is, when the temperature is higher than the threshold value, the control unit 20 does not heat the heater regardless of the snow detection result by the side snow sensor (step S110). As a result, even if the amount of snow sprayed in the horizontal direction is large, it is possible to reduce the possibility of wasteful power consumption in a situation where the snow melts easily and does not easily land on the display surface M.

Further, by arranging the snowfall sensor S below the display plate B, it is possible to block the snow passing from above with respect to the snow detection unit A, and it is not necessary to separately provide a structure for blocking the snow. I'm done. Further, the snowfall sensor S is arranged in front of the bisector X that bisects the bottom surface B1 of the display board B in the front and back. This makes it easier for the bottom surface B1 of the display plate B to block the snow sprayed on the snowfall sensor S from diagonally behind than the snow sprayed on the snowfall sensor S from diagonally front, and the snow sprayed from the front on the display surface M can be made smaller. Can be detected efficiently.

Further, the display surface M and the front surface of the snowfall sensor S are arranged on the same plane. That is, the display surface M (display plate B) is not positioned in front of the front surface of the snowfall sensor S. As a result, it is possible to prevent the display plate B from disturbing the airflow blowing from the front toward the snowfall sensor S, and it is possible to efficiently detect the snow blowing from the front onto the display surface M. Furthermore, by preventing the snowfall sensor S from being positioned in front of the display surface M, it is possible to prevent the snowfall sensor S from impairing the visibility of the display surface M.

(2) Second embodiment:
FIG. 5A is a front view of the display device 101 according to the second embodiment. The difference between the display device 1 of the first embodiment and the display device 101 of the second embodiment is the position of the snowfall sensor S. In the second embodiment, the snowfall sensor S is provided on the right side of the display board B. Since the snowfall sensor S evaluates the possibility of snow accretion on the display plate B, the position of the snowfall sensor S is not particularly limited as long as it is close to the display plate B. For example, a space may be secured between the display board B and the pillar V, and the snowfall sensor S may be arranged in the space.

FIG. 5B is an enlarged side view of the vicinity where the snowfall sensor S is provided. As shown in FIGS. 5A and 5B, the snowfall sensor S is fixed to the right side surface of the display plate B via a connecting member C. The connecting member C includes a fixing portion fixed to the side surface with a bolt, and an arm portion connecting the fixing portion and the snowfall sensor S. The arm portion is formed such that the display surface M of the display plate B and the front surface of the snowfall sensor S are aligned on the same plane. That is, the connecting member C fixes the snowfall sensor S so that the front surface of the snowfall sensor S is inclined by the inclination angle α from the vertical direction.

A roof R is provided above the snowfall sensor S. When the roof R is viewed from above in the vertical direction, the snowfall sensor S and the entire snow detection portion A are covered by the roof R and cannot be seen. The snowfall sensor S is arranged in front of the bisector X that bisects the roof R. The roof R is composed of two planes inclined at an angle larger than 45 degrees with respect to the horizontal plane. Further, the height of the rear end of the roof R is lower than the height of the front end of the roof R.

As shown in FIG. 5B, the trajectory KB (two-dot chain line) of the snow that can obliquely descend from the rear and pass the light ray L of the snow detection unit A without being blocked by the roof R descends obliquely from the front and falls. The angle is closer to horizontal than the snow trajectory KF (two-dot chain line) that can pass the light ray L of the detection unit A. Therefore, it is possible to make it easier for the snowfall sensor S to detect the snow blown from the front than the snow blown from the rear. By lowering the height of the rear end portion of the roof R, it is possible to reliably block the snow sprayed from the rear. In addition, also in the second embodiment, the same processing as the snow accretion prevention processing in the first embodiment may be performed.

In the second embodiment described above, the snowfall sensor S can be arranged at any position by providing the roof R that covers the snowfall sensor S from above. That is, the snowfall sensor S can be arranged at a position other than below the display plate B. By not arranging the snowfall sensor S below the display plate B, the bottom surface B1 of the display plate B can be made flat, and the snowfall sensor S does not get in the way when the display plate B is transported. be able to. Further, since the snowfall sensor S is arranged in front of the bisector X that bisects the roof R, snow blown onto the snowfall sensor S from behind can be easily blocked by the roof R, and the display surface M On the other hand, the snow sprayed from the front can be detected efficiently. Since the roof R is configured by a plane inclined at an angle larger than 45 degrees with respect to the horizontal plane, the possibility that snow will be accumulated on the roof R is reduced, and the snowfall may cause a malfunction of the snowfall sensor S or the like. Can be reduced.

In the first embodiment, snow blown onto the display surface M from the front can be lowered along the display surface M and detected by the snowfall sensor S. On the other hand, in the second embodiment, the snowfall sensor S is unlikely to detect the snow sprayed on the display surface M. Therefore, in the first embodiment, the amount of snow detected by the snowfall sensor S is likely to be larger than that in the second embodiment. Therefore, the determination values T1 to T3 of the first embodiment may be set to values larger than the determination values T1 to T3 of the second embodiment.

(3) Other embodiments:
In the above-described embodiment, an example in which the display plate B or the roof R has a function of blocking snow from above is shown, but the snow from above is blocked by other members constituting the display device 1. Good. For example, the snowfall sensor S may be arranged below the horizontal beam Y that connects the display board B and the support V on the back surface of the display board B. In addition, when the fixed type marking device such as a road sign having a small depth on the bottom surface B1 of the display board B is heated by the heater, the second embodiment in which the snowfall sensor S is arranged on the side surface of the display board B is applied. Is preferred. Further, the snowfall sensor S only needs to be arranged in a direction in which snow can enter the snow detection portion A from the front, and the surface T shown above in FIG. 2 does not have to be arranged in a direction facing forward.

Further, at least a part of the snow detection portion A of the snowfall sensor S may be shielded by the display plate B and the roof R when viewed from above vertically, and the entire snow detection portion A does not necessarily have to be shielded. Even if only a part of the snow detecting portion A of the snowfall sensor S (for example, 50% or more, preferably 70% or more of the projected area from vertically above) is shielded, it is difficult for the snow from above to pass through the snow detecting portion A. You can

Further, the amount of heat generated by the heater 12 does not necessarily have to be controlled in multiple stages, and the heater 12 may simply be switched on/off in accordance with the amount of snow detected by the snowfall sensor S. Furthermore, in the present invention, the temperature sensor 30 is not essential, and the temperature sensor 30 and steps S100 to S105 of FIG. 4 may be omitted.

Further, the snowfall sensor S does not necessarily have to be arranged in front of the bisector X that bisects the bottom surface B1 of the display board B or the roof R into front and rear. Of course, the display surface M and the front surface of the snowfall sensor S do not have to be aligned on the same plane. For example, instead of arranging the snowfall sensor S in front of the bisector X that bisects the bottom surface B1 of the display board B or the roof R in the front and back, an eave that blocks snow from the rear is placed behind the snowfall sensor S. You may arrange. Even in this case, it is possible to detect the snow blown on the display surface M mainly from the front.

Further, the shape of the roof R is not limited to the shape shown in FIGS. 5A and 5B. For example, a single flat roof R may be provided, the height of which decreases toward the rear. In this case, it is possible to reduce the possibility that snow falls from the front end of the roof R and is detected by the snowfall sensor S.

1, 101... Display device, 11... Display unit, 12... Heater, 20... Control unit, 21... Control program, 21a... Display control module, 21b... Heater control module, 30... Temperature sensor, 40... Power supply unit, 50... Power supply circuit, A...snow detecting portion, B...display plate, B1...bottom surface, C...connecting member, KB, KF...snow locus, L...light ray, M...display surface, R...roof, S...snowfall sensor, Y... Horizontal beam, S1... Light emitting part, S2... Light receiving part, T1... 1st judgment value, T2... 2nd judgment value, T3... 3rd judgment value, V... Strut, X... Bisecting line, Z... Side snow Sensor.

Claims (9)

Display board,
A heater for heating the display surface of the display plate,
A snow detecting section for detecting passage of snow, the snow detecting section including a light emitting section on one side surface in the width direction of the display plate and a light receiving section on the other side surface in the width direction. A lateral snow sensor formed by arranging a sensor so as to block snow passing from above with respect to the snow detection unit,
A control unit that controls the amount of heat generated by the heater based on the snow detection result of the lateral snow sensor;
Display device. The control unit increases the amount of heat generated by the heater as the amount of snow detected by the lateral snow sensor increases.
The display device according to claim 1. When the temperature is equal to or lower than a threshold value, the control unit heats the heater based on a snow detection result by the side snow sensor.
The display device according to claim 1. By disposing the snowfall sensor below the display plate, snow passing from above with respect to the snow detection unit is blocked.
The display device according to any one of claims 1 to 3. The snowfall sensor is arranged in front of a bisector that bisects the bottom surface of the display plate.
The display device according to claim 4. By providing a roof that covers the snowfall sensor from above, snow passing from above with respect to the snow detection unit is blocked.
The display device according to any one of claims 1 to 3. The snowfall sensor is arranged in front of a bisector that bisects the roof.
The display device according to claim 6. The display surface and the front surface of the snowfall sensor are arranged on the same plane,
The display device according to any one of claims 1 to 7. A display panel, a heater for heating the display surface of the display panel, a snow-accretion preventing method for a display device comprising a,
A snow detecting section for detecting passage of snow, the snow detecting section including a light emitting section on one side surface in the width direction of the display plate and a light receiving section on the other side surface in the width direction. The amount of heat generated by the heater is controlled based on the snow detection result of the lateral snow sensor formed by arranging the sensor so as to block the snow passing from above with respect to the snow detection unit.
A method for preventing snow accretion on a display device.

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