JP7655511B2 - Display unit - Google Patents

Description

The present invention relates to indicators such as traffic signals that can prevent snow from accumulating, particularly in snowy regions.

In recent years, with the changes in the global environment, damage caused by heavy snow blown by strong winds in winter has become a problem. Heavy snowfall not only creates obstacles to road traffic, but also causes snow to accumulate on traffic signal lamps due to blizzards, blocking the light emission of the traffic signals and making the traffic signals invisible. For this reason, measures to prevent snow accumulation on traffic signals during blizzards are needed.

One way to deal with this type of snow accumulation is to provide a hood or cover to cover the traffic light (for example, Patent Document 1 and Patent Document 2).

There are also methods for melting snow using a heating element (e.g., Patent Document 3 and Patent Document 4).

However, while methods such as those described in Patent Documents 1 and 2 that provide large hoods may make snow less likely to accumulate, once snow does accumulate, the snow will continue to grow and impair the visibility of the traffic light.

In addition, when infrared rays are used as a heat source as in Patent Document 3, electrical energy is converted into light, which results in poor efficiency in conversion and absorption, and the difficulty of requiring an extremely large amount of electrical energy to generate sufficient heat to remove snow from the light-emitting surface.

In addition, Patent Document 4 provides a cover to form a dark portion that absorbs light, which is a heat source, and generates heat, but this has problems in that it is inefficient when using light as an energy transmission means, and covering the traffic light with such a material impedes visibility under normal conditions.

In response to this, a display has been proposed in which multiple light source arrangement sections are arranged at a specified interval so that wind and snow from the front can pass through the gaps between adjacent light source arrangement sections to the rear (Patent Document 5).

JP 2008-305025 A Publication No. 2009-190554 Utility Model Registration No. 3161877 JP 2012-108861 A JP 2021-26658 A

According to Patent Document 5, snow blown in from the front passes through the gaps between adjacent light source arrangement sections to the rear, so by appropriately setting the gaps between the light source arrangement sections, it is possible to prevent snow from accumulating on the front of the light source arrangement sections. However, if even a small amount of snow adheres to the front of the light source arrangement section, there is a risk that this will become the nucleus from which the snow accumulation area will expand.

In addition, the width of the light source arrangement section cannot be made wide because gaps must be created between adjacent light source arrangement sections to allow wind and snow to pass through. For this reason, there is a limit to the size of the light source 5 arranged in the light source arrangement section, and it is desirable for the light source 5 to also have the function of effectively collecting and distributing the total luminous flux emitted by the light source.

The present invention was made in consideration of these problems, and aims to provide an energy-saving display and traffic light that has a simple structure, efficiently prevents snow from accumulating, and is capable of distributing signal light.

To achieve the above-mentioned object, the present invention provides a display comprising a light source arrangement section in which a light source is arranged, a transparent cover provided on the light-emitting surface side of the light source arrangement section to protect the light source, and a frame section to support the light source arrangement section, the light source arrangement sections being arranged at predetermined intervals, allowing wind and snow from the front to pass through gaps between adjacent light source arrangement sections to the rear, and the transparent cover being a triangular prism member having a generally triangular portion protruding forward in a cross section perpendicular to the longitudinal direction.

The transparent cover may be roughly home plate shaped, with side portions that are roughly parallel in the front-to-rear direction and behind the triangular portion.

It is desirable that the angle of the front apex of the transparent cover be approximately 100° or less.

It is desirable that the light source be a planar LED light source, and that the rear surface of the transparent cover be in surface contact with the light-emitting surface of the LED light source.

According to the present invention, gaps are formed between multiple adjacent light source arrangement sections, through which wind can pass, and because the shape of the transparent cover is a roughly triangular shape facing forward, the area where stagnation points of the wind flow occur in front of the light source arrangement section is reduced, making it possible to reduce snow accumulation on the front surface of the light source arrangement section. In addition, the lens effect caused by the refraction of light through both sloped sections of the triangle shape causes the light emitted from the LED light source to be concentrated forward. As a result, the internal light source appears to be expanded when viewed from the front, thereby improving visibility.

In addition, if the angle of the front apex of the transparent cover is approximately 100° or less (i.e., the base angle of the isosceles triangle is approximately 40° or more), this will be greater than the angle of repose of snow, so snow accumulation on the left and right slopes can be more reliably suppressed.

In addition, by using a flat LED light source as the light source and bringing the rear surface of the transparent cover into surface contact with the light-emitting surface of the LED light source, the light emitted from the light source can be efficiently guided into the triangular prism-shaped transparent cover, improving visibility from the front.

The present invention provides a display and a traffic light that are energy-saving, have a simple structure, and can efficiently prevent snow accumulation.

1A is a front view of the traffic light 10, and FIG. 1B is a cross-sectional view of the traffic light 10 taken along line B-B in FIG. 4A is an enlarged cross-sectional view of the light source mounting section 3, and FIG. 4B is a diagram showing the flow of air and the like relative to the light source mounting section 3. FIG. 13A and 13B are diagrams showing different shapes of the transparent cover, and 13C and 13D are conceptual diagrams showing the visibility of the light source 5 when viewed from the front. Actual photographs of Fig. 3(c) and Fig. 3(d). 4A and 4B are diagrams showing the light distribution characteristics of a light source 5 for FIGS. 3A and 3B. FIG. 13A and 13B are diagrams showing another transparent cover 9b. FIG. 4A is a perspective view showing the display unit 1a, and FIG. 4B is a side view showing the display unit 1a.

Below, an embodiment of the present invention will be described with reference to the drawings. Fig. 1(a) is a front view of a traffic light 10, and Fig. 1(b) is a cross-sectional view of the traffic light 10 taken along line B-B in Fig. 1(a). In the following description, an example of a traffic light 10 having three indicators 1 connected together will be described, but the indicators 1 of the present invention may be connected vertically or may be a double traffic light. In addition to traffic lights, the indicators 1 can also be used as indicators for expressway toll gates, or indicators for displaying traffic information, warnings, expressway toll gate indicators, signs, etc. The indicator 1 is mainly composed of a light source arrangement section 3, a light source 5, a frame section 7, etc.

In the light source arrangement section 3, multiple light sources 5 are arranged in the longitudinal direction. The light sources 5 are, for example, LED light sources. In the illustrated example, the light sources 5 are arranged in a row in each light source arrangement section 3, but they may be arranged in two or more rows. However, as described below, if the width of the light source arrangement section 3 is widened, the amount of snow that accumulates may increase, so it is preferable that the width of the light source arrangement section 3 is narrow.

The light source arrangement sections 3 are arranged parallel to each other at a predetermined interval. In the illustrated example, the light source arrangement sections 3 are arranged in a vertical lattice pattern. The frame section 7 supports the light source arrangement sections 3 at least at the upper and lower parts of the light source arrangement sections 3. In this way, gaps are formed between the light source arrangement sections 3, so that a snowstorm from the front can pass through the gaps between adjacent light source arrangement sections 3 to the rear. Note that forming a gap between adjacent light source arrangement sections 3 means that there is a space between adjacent light source arrangement sections 3 through which wind can pass. For example, adjacent light source arrangement sections 3 may be partially connected, or a portion between the light source arrangement sections 3 may be blocked. Note that the details of the air flow will be described later.

Multiple light sources 5 are arranged in each light source arrangement section 3. Since the light source arrangement sections 3 are of approximately the same length and are arranged at a predetermined interval, the light emitting area in which the light sources 5 can be installed is approximately rectangular. In the multiple light source arrangement sections 3 arranged in this approximately rectangular shape, the light sources 5 are arranged so as to form an approximately circular shape when viewed from the front (A in the figure). In this way, light can be emitted in an approximately circular shape, which can be recognized as circular light.

It should be noted that there is also a method of covering everything except the circular light-emitting part with a shielding plate or the like, but in this case, the shielding plate fills the gap between adjacent light source arrangement parts 3. As a result, the shielding plate prevents the flow of fluid (wind and snow) between adjacent light source arrangement parts 3. For this reason, it is preferable to form a roughly circular light-emitting area by arranging the light sources 5 in the light source arrangement part 3, rather than blocking a part of the light source arrangement part 3.

Figure 2(a) is an enlarged cross-sectional view of the light source arrangement section 3. The light source arrangement section 3 is, for example, a rail with a substantially H-shaped cross section, on which a board on which the light source 5 is arranged is joined. In addition, a transparent cover 9 that protects the light source 5 is disposed on the light-emitting surface side of the light source 5 in the light source arrangement section 3 and is integrated with the light-emitting surface side of the light source 5.

The transparent cover 9 is a triangular prism member (excluding hollow members) that has a generally triangular portion (dotted line in the figure) protruding forward in a cross section perpendicular to the longitudinal direction. The light source 5 is a planar LED light source, and the flat surface on the rear side of the transparent cover 9 is in surface contact with the light emitting surface of the LED light source. In other words, there is no light reflecting surface between the emission surface of the light source 5 and the front surface of the transparent cover 9. By eliminating the air layer between the light source 5 and the transparent cover 9 in this way, the light emitted from the light source 5 can be efficiently introduced into the transparent cover 9. The transparent cover 9 can be made of resin or glass with a refractive index greater than 1.

In the illustrated example, the transparent cover 9 has a triangular portion (dotted line portion) at the front with a slope 15 that slopes from the center to the rear, and a side portion 13 that is approximately parallel in the front-to-rear direction (left-to-right direction in the figure) behind the base of the isosceles triangle. That is, in the illustrated example, it has a roughly home plate-shaped configuration in which an isosceles triangle with an apex angle facing forward is connected to a rectangle provided behind it. The side portion is parallel to the airflow and is not subject to snow accumulation. Even if snow accumulates on the top of the front surface during a heavy snowstorm, light emitted from this side portion will emit a signal light.

Here, it is desirable for the base angle (θ in the figure) of the transparent cover 9 to be approximately 40° or greater. For example, in places with a surface perpendicular to the flow of snowstorms, the flow stops and loses speed, creating stagnation points, which act as nuclei for snow particles to adhere to the surface of objects. At this time, the outline of the snow forms an angle of repose, which has been reported to be approximately 40° ("Transition of Road Icing Prevention Technology (2) Snowstorm Prevention and Research for Traffic Security and Safety" by Takeuchi Masao, Kita no Kousaten vol. 3, SPRING-SUMMER 1998, pp. 10-17; "Experimental Research on Snow Accretion Properties of Structural Members - Snow Particle Collision Rate and Snow Accretion Rate" by Sato Yuki et al., Hokkaido University of Science Research Bulletin No. 39 (2015), pp. 1-6; "Snow Accretion and Prevention on Road Signs" by Takeuchi Masao et al., Civil Engineering Laboratory Monthly Report, October 1978, No. 305, pp. 11-19).

In other words, if the base angle of the transparent cover 9 is approximately 40° or more, snow accumulation on the slope 15 can be suppressed.

Figure 2(b) shows the wind flow (C in the figure) from the front (left side in the figure) of the light source arrangement section 3. If a surface approximately perpendicular to the airflow exists at the tip of the approximate center of the light source arrangement section 3, a stagnation point where the airflow speed is approximately zero is formed where the airflow collides (D2 in the figure). At stagnation point D2, the light source arrangement section 3 is pushed by the flow due to the conversion of dynamic pressure and the kinetic energy of the snow particles into thermal energy.

For example, in a snowstorm containing snow particles, snow particles that reach stagnation point D2 collide with light source arrangement section 3 and are pressed against light source arrangement section 3 by dynamic pressure, causing snow to accumulate, which is thought to result in a large amount of snow accumulating at and near the stagnation point.

However, in this embodiment, the stagnation point D2 is the apex of a triangle, so the area of the surface approximately perpendicular to the airflow is extremely small (ideally, the apex is a ridgeline with an area of 0). This makes it possible to prevent snow from accumulating at the stagnation point. As described above, the base angle of the sloped portion 15 relative to the base is greater than the angle of repose, and because wind-blown snow flows rearward, even if a small amount of snow accumulates on the top of the transparent cover 9, further growth of the snow is prevented.

Next, the visibility of the light emitted from the light source will be described. FIG. 3(a) is a diagram showing a light source arrangement section 3 using a transparent cover 9a having a surface that is approximately perpendicular to the air flow described above as a comparative example, and FIG. 3(b) is a diagram showing a light source arrangement section 3 using a transparent cover 9 whose front is triangular (isosceles triangle with an apex angle of 90°). Note that FIG. 3(b) shows an example in which the sloped portion is flat, but the results are approximately the same even if the sloped portion is curved forward. In other words, the same tendency is observed even if the sloped portion has a gentle arc shape that is convex forward near approximately the center in the width direction (left-right direction in the figure).

3(c) is a diagram showing how the light source 5 looks when viewed from the front (arrow C) of FIG. 3(a), and FIG. 3(d) is a diagram showing how the light source 5 (light from the light source 5) looks when viewed from the front (arrow D) of FIG. 3(b). As shown in FIG. 3(c), when the front surface of the transparent cover 9a is flat (or a gentle arc), the light-emitting area of the light source 5 (E in the figure) seen through the transparent cover 9a from the front is visually recognized as being approximately the same size as the size of the light source 5. On the other hand, as shown in FIG. 3(d), when the transparent cover 9 is triangular and protrudes forward, the light-emitting area of the light source 5 is visually recognized on both sides of the center (vertex) in the width direction due to refraction of light when it is emitted from the triangular prism into the atmosphere. In other words, the area of light from the light source 5 seen through the transparent cover 9 (F in the figure) is sufficiently larger than the size of the original light source 5.

The photograph on the left side of Figure 4 is an actual photograph corresponding to Figure 3(c), and the photograph on the right side of Figure 4 is an actual photograph corresponding to Figure 3(d). In this way, by making the front of the transparent cover 9 triangular, the light-emitting area (size) of the light source 5 as seen from the front can be made roughly twice as large.

By focusing light forward from each light source arrangement section 3, adjacent light source arrangement sections 3 become a group that emits signal light forward. In this case, it is possible to significantly improve visibility while saving power without changing the number of light sources 5 or power consumption.

Figure 5(a) shows the evaluation results of the light distribution characteristics of the light emitted from the light source 5 with the transparent cover removed (roughly corresponding to the left side of Figure 4). Also, Figure 5(b) shows the evaluation results of the light distribution characteristics of the light emitted from the light source 5 with the triangular prism-shaped transparent cover 9 attached (corresponding to the right side of Figure 4). The LED light source consisted of 15 LED elements mounted at equal intervals on an aluminum rail 25 cm long and 12 mm wide, and driven at 12 V. The height of the center of the light source and the illuminometer were set to be the same, and the measurement distance was 1 m.

As shown, in both cases, the intensity of the light emitted from the light source 5 is stronger toward the center and weakens as the light distribution angle increases, but in Figure 5(b), which uses a triangular transparent cover 9, the light emitted forward is stronger. In other words, by using a triangular prism-shaped transparent cover 9, the light spreading to the left and right is concentrated in the center (forward), and the central area is about twice as bright as the comparative example. Also, in Figure 5(b), the angular range in which the brightness was equal to or greater than that of Figure 5(a) was approximately 60° (a range of 30° to the left and right from the center).

As described above, according to this embodiment, by making the front surface of the transparent cover 9 into a triangular prism shape, it is possible to minimize stagnation points and suppress the adhesion of snow, which is the nucleus of initial snow accumulation.

In addition, by making the inclination angle of the sloped portion 15 of the transparent cover 9 equal to or greater than the angle of repose, snow accumulation on the left and right slopes of the transparent cover 9 can be further suppressed. In addition, the structure allows snow to blow through between the multiple light source arrangement sections 3 where the light sources 5 are arranged, which significantly reduces snow accumulation on the light emitting surface of the light source arrangement section 3, making it possible to eliminate snow accumulation.

In addition, the light intensity of the light source 5 when viewed from the front can be increased, thereby improving visibility from the front.

In order to achieve this effect, the shape of the transparent cover is not limited to the home plate shape, and for example, a transparent cover 9b having an overall triangular prism shape as shown in FIG. 6 may be used. In this way, as long as it has a triangular prism shape that protrudes forward, there are no particular limitations on the cross-sectional shape.

Next, another embodiment will be described. Fig. 7(a) is a rear perspective view showing the display unit 1a, and Fig. 7(b) is a side view of the display unit 1a (a perspective view of the frame, etc.). In the following description, components having the same functions as the above-mentioned embodiment are given the same reference numerals as in Figs. 1 to 3, and duplicated descriptions will be omitted.

The display 1a has a similar configuration to the display 1, but is different in that a light shielding member 17 is additionally arranged behind the light source arrangement section 3 to allow wind to pass through. In the display 1a, a plurality of light shielding members 17 are arranged in a plurality of stages. In the figure, an example in which the light shielding members 17 are arranged in three stages is shown, but the number of stages of the light shielding members 17 is not particularly limited. The plurality of light shielding members 17 are arranged at a predetermined interval in the vertical direction. Each light shielding member 17 has a tapered portion that slopes downward as it goes rearward, and the tapered portions are formed approximately parallel to each other. In a rear view (front view), the plurality of stages of light shielding members 17 are arranged so as to overlap each other in the vertical direction. For example, the lower end of the upper stage light shielding member 17 overlaps in height with the upper end of the light shielding member 17 in the stage below.

The tapered portions of all the light blocking members 17 are formed at positions spaced a predetermined distance rearward from the frame portion 7. The topmost light blocking member 17 has a horizontal portion (a portion that is approximately perpendicular to the direction in which the light source arrangement portions 3 are arranged) in front of the tapered portion, and an eave is formed so as to protrude forward of the frame portion 7. In other words, the light blocking members 17 from the second row down from the top are positioned at positions spaced a predetermined distance rearward from the frame portion 7.

Each light blocking member 17 is supported by a frame that is disposed rearward from the side of the frame 7. That is, the light blocking member 17 is fixed to the frame 7 via the frame. Note that in the illustrated example, the frame is exposed on the side, but the side of the light blocking member 17 may be blocked by a plate-shaped member (not shown).

As mentioned above, because gaps are formed between adjacent light source arrangement sections 3, it is possible to see the scenery behind the display unit and sunlight from behind from the front of the display unit. This may impair the visibility of the light emitting unit in front of the display unit. In response, by disposing the light blocking member 17, light from behind the display unit 1a is blocked, and the visibility of the light from each light source 5 of the light source arrangement section 3 can be improved.

The multiple light blocking members 17 are also arranged with gaps between them, allowing the wind passing between adjacent light source arrangements 3 to flow directly to the rear of the display unit 1a. Therefore, even if light from the rear is blocked, the flow of wind is not impeded. This makes it possible to prevent snow from accumulating on the front of the light source arrangements 3.

Note that the arrangement and shape of the light blocking member are not limited to the example shown in FIG. 7. Other shapes are also acceptable as long as they can block light from the rear and allow air to flow rearward.

As described above, according to this embodiment, by disposing a light-blocking member behind the display unit, it is possible to prevent light from leaking from behind the display unit through the gap between adjacent light source arrangement units 3. In addition, because there is a gap between the light-blocking member 17 and the frame unit 7, it is possible to maintain the snow accumulation suppression effect without blocking the air flow.

Although the embodiment of the present invention has been described above with reference to the attached drawings, the technical scope of the present invention is not limited to the above-mentioned embodiment. It is clear that a person skilled in the art can come up with various modified or revised examples within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present invention.

1, 1a... Display unit 3... Light source installation section 5... Light source 7... Frame section 9, 9a, 9b... Transparent cover 10... Traffic light 13... Side section 15... Inclined surface section 17... Light blocking member

Claims (4)

a light source arrangement section in which a light source is arranged;
a transparent cover provided on a light emitting surface side of the light source arrangement portion to protect the light source;
A frame portion supporting the light source arrangement portion;
Equipped with
The light source arrangement sections are arranged at predetermined intervals, and wind and snow from the front can pass through gaps between adjacent light source arrangement sections to the rear,
A display device characterized in that the transparent cover is a triangular prism member having a generally triangular portion protruding forward in a cross section perpendicular to the longitudinal direction. The display device according to claim 1, characterized in that the transparent cover is approximately home base shaped, with side portions approximately parallel to the front-to-rear direction, rearward of the triangular portion. The display device according to claim 1, characterized in that the angle of the front apex of the transparent cover is 100° or less. The display device according to claim 1, characterized in that the light source is a flat LED light source, and the rear surface of the transparent cover is in surface contact with the light-emitting surface of the LED light source.

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