JP2010002650A - Self-luminous road sign plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate drawbacks of a road sign plate such that conventionally a retroreflective sheet is stuck to the surface of a road sign plate so as to use the light from a headlight of a vehicle at night to efficiently reflect the light in the direction of the incident light, however, the plate surface becomes hardly visible because of insufficient luminous energy of incident light when a headlight of a vehicle is at a low angle. <P>SOLUTION: The road sign plate is prepared by sticking a retroreflective sheet 5 to the surface of a "self-luminous plate", which includes a light guide plate 1 and a light-diffusing plate 2 applied thereon, and removing characters and marks to expose the underlay light diffusing plate. Visibility of the plate at night can be enhanced by allowing the "self-luminous plate" to emit light to illuminate the characters and marks. The "self-luminous plate" includes a light guide plate made of a transparent acrylic plate and a light-diffusing plate made of an opaque acrylic plate as a pair, and an edge light comprising an belt-like array of LEDs to emit light as a light source. A retroreflective sheet that does not transmit light is stuck to the surface of the "self-luminous" plate, which provides a long-life energy-saving sign plate free of light pollution by light leakage with less power consumption. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a method for improving visibility at night by causing characters and marks to self-emit by road signs.

This is due to the progress in practical use of edgelights that emit light with a narrow width that matches the width of the light guide plate.

LED power consumption is small and energy-saving, and it has a long life span and can greatly reduce the number of light source replacements, making it suitable as a light source for road signs.

We were able to create a technology that uniformly changes the direction of the light from the edge light to create a uniform light surface on the board surface.
There are a printing method and a cutting groove method for changing the direction of light.

A light blocking type that does not allow light to pass through the back of the retroreflective sheet and a light transmissive type that allows light to pass through have been made. In this way, a self-luminous light can be added to the reflected light to produce a signboard with improved visibility.
JP 2000-276084 A JP2003-242815

A retro-reflective sheet is attached to the surface of the road sign board so as to reflect light efficiently in the direction of incident light using the light of a headlight of a night vehicle. However, when the vehicle headlight is at a low angle, the amount of incident light is insufficient, making it difficult to see the board surface. Various measures are being taken as countermeasures, but each has its own drawbacks, and a solution is awaited.

There is a method to brighten the board surface by providing a fluorescent lamp on the top of the sign board. However, when the size of the sign board increases, light does not reach the lower part, and the brightness of the board surface can be different, which is not practical for large size sign boards.

There is a far-field illumination system in which a spotlight is provided 20m to 30m in front of the sign board to illuminate the board surface, but there is a problem that light from the spotlight leaks to other than the board surface and causes light pollution.

A metal halide lamp or the like is used for the far-distance illumination method, and the power consumption is large at 400 w to 600 w per lamp and the running cost is high.

The life of the light bulbs such as the metal halide lamps used for far-distance lighting is as short as about 5000 hours, and it is necessary to replace the light bulbs once a year on average, which requires costs such as material costs and labor costs. Also, in places with heavy traffic, traffic regulations and dedicated vehicles need to be dispatched, and the burden of expenses for bulb replacement is large.

In recent years, wide-angle reflective films have emerged that do not use fluorescent lamps or remote lighting. However, when the headlight of a car becomes a low angle, there is a problem that the amount of light hitting the sign board is small and the visibility is poor.

A retroreflective sheet is attached to the surface of the “self-light-emitting plate” provided with a light diffusing plate on the light guide plate, characters and mark portions are removed, and the underlying light diffusing plate is exposed. Visibility at night can be improved by shining the “self-light-emitting plate” to self-light the characters and the mark portion.

The “self-light emitting plate” is a pair of a light guide plate made of a transparent acrylic plate and a light diffusing plate made of a milky white acrylic plate, and the light source is composed of edge lights that emit light by arranging LEDs in a strip shape. Light can be introduced from the side surface of the light guide plate by the edge light, and a light surface can be created by the light diffusion plate so that the surface has uniform brightness. For this reason, unevenness of light on the board surface does not occur.

Since a retroreflective sheet that does not transmit light is affixed to the surface of the “self-light-emitting plate”, no light is emitted except for characters and mark portions. Therefore, light pollution due to light leakage does not occur.

LED light sources consume less power. Compared to the average 400w distance metal halide lamp for distant illumination at about 10m ² , LED power consumption is reduced by 75% at about 100w, thus realizing energy saving.

LED light sources have a long life. Compared to 5000 hours of metal halide lamps, the LED will be 50,000 hours, and the bulb replacement during this period can be almost eliminated, greatly reducing the cost of replacement.

By making the character or mark self-emit, visibility can be sufficiently improved without receiving external light compensation.
Moreover, the low visibility of the low angle of the headlight of the car, which is a problem of the wide-angle reflecting sheet, can always improve the visibility by the self-light emission.

The self-luminous sign board can improve the visibility without inferiority compared to external illumination using fluorescent lamps or far-field illumination that illuminates the board surface from a distance of 20 m-30 m.
Furthermore, compared with the wide-angle reflective film type, as shown in “Table-1”, the visibility is greatly improved.

As shown in Fig. 1, a retroreflective sheet (5) is attached to the entire surface of the sign board. The reflective sheet is cut off from the characters and marks, and the underlying light diffusion plate (2) is exposed.

As shown in FIG. 2, a light guide plate (1) is further provided under the light diffusion plate (2), and light conversion printing (8) or cutting grooves (19) are provided on one side. .
A reflection sheet (4) is provided in order to efficiently direct light from the light conversion section toward the board surface.
In this way, the light that has traveled through the light guide plate is redirected by the light conversion unit and directed to the board surface, and the sign plate self-emits.

The entire sign board receives the car light and emits reflected light in the direction of incident light to brighten the entire sign board. This indicates to the driver the presence of the signboard. The guidance can be clearly shown by making characters and marks shine stronger than the reflected light.
In particular, when the vehicle is in a low angle where the light does not reach, self-luminous light can ensure unchanging visibility.

The edge light provided on the side surface of the light guide plate (1) uses the LED (3) and exhibits high luminous efficiency with low power consumption.
LEDs have a long life span, an average durability of 50,000 hours, and do not require replacement for 10 to 15 years.

The illuminance of self-light emission is not to be bright. If it is too bright, the surrounding reflection sheet portion cannot be seen. If it is too dark, characters or marks cannot be seen.
As shown in “Table-2”, the illuminance is preferably 100 lux to 200 lux.

FIG. 2 is a cross-sectional view of a self-luminous label plate. Incident light (10) from the car becomes reflected light (11) and is visually recognized by the driver. The character and the mark part (6) self-emit by light stronger than the reflected light (11), and the light is clearly delivered to the driver and can be clearly read.

FIG. 3 shows the types of retroreflective sheets. A type glass bead type reflects the incident light at a narrow angle, so it is suitable for incident / reflection from a long distance, but when the light is at a short distance and the light is at a low angle, Light does not reach the sign board and the display surface cannot be read.
Since the B type prism sheet type is incident and reflected at a relatively wide angle, the surface of the sign board is bright even at low angles, making it suitable for reading the display surface.
However, as shown in the above (0018), it does not reach the self-luminous type.

The self-luminous sign board shown in Fig. 2 can be used as it is, or multiple self-luminous small panels can be attached to a large retroreflective sheeting sign board and used as a single sign board. good.

You may affix the light transmissive type of a retroreflection sheet to the exposed part (6) of the light diffusing plate shown in FIG. The reflected light is added to the self-light emission, and the visibility can be improved.
In the unlikely event that the LED light source does not turn on, a certain level of visibility can be maintained by the function of the reflective sheet.

Front view of self-luminous sign board Cross section of self-luminous style plate Glass beads retroreflective sheet (A-light-shielding type) (B-transmitted light type) Prism-type retroreflective sheet (A-shading type) (B-transmitted light type) Light conversion part (A-printing type) (B-cutting groove type)

Explanation of symbols

1 Light guide plate 2 Light diffusion plate 3 LED
4 Reflective sheet 5 Retroreflective sheet 6 Light diffusion plate, exposed portion 7 Outer frame 8 Light converting portion 9 Light traveling in the light guide plate 10 Incident light 11 Reflected light 12 Self-luminous 13 Glass beads 14 Glass bead fixing resin 15 Light blocking layer 16 Adhesive layer 17 Light conversion printing 18 Light conversion light 19 Light conversion cutting groove 20 Prism film 21 Air layer 22 Film fixing resin 23 Base film 24 Surface film

Claims (3)

Self-illuminated retroreflective sheet with the letters and marks removed, and the letters and marks exposed, on the surface of the “self-luminous plate” that combines the light guide plate, light diffuser and LED edge light Luminous road sign board. A plurality of small plates attached with a light-shielding retroreflective sheet from which letters and marks are removed from the surface of the "self-light-emitting plate" are attached to a board surface on which a retroreflective sheet is attached to the entire surface of the sign board. The self-luminous road sign board according to 1. The retroreflective sheet having translucency is pasted on the surface of the “self-light-emitting plate” on the character and the mark part, and the retroreflective sheet having light shielding property is pasted on a part other than the character and the mark part. 2. A self-luminous road sign board according to 2.

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