Traffic sign reflective film of reflective material

Reflective film is a retroreflective material that has been made into a thin film and can be directly applied. It is also the most widely used retroreflective material. In 1937, the world's first reflective film was born in the laboratory of 3M Company in the United States. This is the starting point of the history of large-scale application of reflective film on traffic signs. In 1939, a sign made of Scotchlite TM reflective film was used for the first time in the open air on the side of a highway in Minnesota, USA. Since then, a new era of a series of reflective products for traffic signs has been opened and a new era has been created. A whole new traffic safety industry. This year, the U.S. national standards for traffic signs (1939 edition of the U.S. Manual of United Traffic Control Devices, 1939) officially stipulated that reflective films should be used to manufacture traffic signs.

Since then, with the development of the chemical industry, especially synthetic resins, various R&D institutions have continued to research and innovate, using glass bead technology, synthetic resin technology, film technology and coating technology to develop a series of high-tech products. Quality retroreflective products.

Beginning in the 1940s, this initially manufactured reflective film was dubbed "engineering grade" reflective film and began to be widely used in road traffic signs. Since then, a series of products such as reflective films used in personal safety protection fields such as clothing have also been developed with the advent of synthetic resins and the needs of social development. Since then, with a series of research results in material technology and optical technology, especially the emergence of microprism reflective materials, this reflective material, which was originally mainly used for traffic signs, began to be gradually replaced by newer and better reflective materials.

There are many ways to classify reflective films. Among them, the more commonly accepted classification principle is based on the basic structure of the retroreflective unit and the ranking method based on the retroreflection coefficient of the front photometric performance of the reflective film. However, considering the different processes of reflective films, some are specifically designed to solve the problem of non-frontal retroreflective brightness, some take into account both performance, and some are aimed at visual recognition requirements under harsh climate conditions, so this classification method is also There are deficiencies. Therefore, it is very necessary to be familiar with and master the application conditions and design functions of various reflective films.

In traditional customs, reflective films are divided into two categories based on the structure of the reflective unit of the reflective film, glass bead reflective film and microprism reflective film. Each type of reflective film also includes many types, such as micro-prism reflective film. Due to the adoption of more advanced technology, there have been many changes in material selection and prism structure, which can cope with more traffic needs. According to the form and technical characteristics of the prism, microprism reflective films can be divided into truncated prism reflective films with good long-distance retroreflective properties, truncated prism reflective films with good short-range and large-angle retroreflective properties, and truncated prism reflective films with good long-distance retroreflective properties. Full-prism reflective film that meets the needs of customers, fluorescent full-prism reflective film that has good performance during the day and in harsh weather conditions, prism-type reflective film that meets traditional engineering-grade retroreflective parameters, etc.

Glass bead type reflective film appeared earlier, but its process changes are relatively few. There are two main types, one is the lens embedded type reflective film, which is customarily called engineering grade reflective film; It is a sealed capsule type, usually called a high-strength reflective film. Due to application needs, it should be noted that in the lens-embedded reflective film, due to its long history, different manufacturers have a long production and manufacturing process. , using the differences in the diameter, density, and weather-resistant coating thickness of the lens, many types of reflective films are produced, such as super engineering-grade reflective films, which are mainly based on engineering-grade reflective films and use higher-quality glass beads. And increase the density of glass beads to improve some brightness; commonly known as economic-grade reflective film, mainly produced in China, it is basically based on the technology of engineering-grade reflective film, by reducing the number and density of lenses (glass beads) The reflective ability of these two kinds of reflective films, economic-grade reflective films, cannot meet the needs of traffic safety. They are mostly used in the commercial field. They are rarely included in traffic safety standards in the world. among.

When it comes to the scientific classification method of reflective films, we cannot leave out the reflective film standards that have great guiding significance for the application of reflective films. Among the reflective film standards in various countries around the world, the American Society for Testing and Materials standards, Australian and New Zealand standards, and the U.S. Federal Highway Administration Traffic Sign Retroreflective Materials Guidance, etc., research and application of retroreflective materials to make traffic signs in various countries around the world, improve Traffic safety has played a positive guiding role. Below, we introduce them one by one.

The American Association of Materials and Testing is an international organization for materials testing standards with a long history. Its full English name is Association of Standard Testing of Materials, or ASTM for short. It was established to provide information to the scientific community and industry. Provide a series of material testing standards to achieve the definition of new materials and provide a technical platform for mutual communication for the scientific community around the world. Provide technical support for testing standardization of retroreflective materials, as well as many materials in various industrial fields such as petroleum, natural gas, and chemicals.

In view of such technical traceability, ASTM’s testing standards for retroreflective materials are also cumulatively carried out with the invention and use of retroreflective materials. Every time a new material appears, as long as this Once a material has been around for a period of time and its manufacturer applies to ASTM for inclusion, its committee will authorize the classification of this material and establish testing standards. It is for this reason that in the ASTM4956 reflective film standard, there are as many as 11 types of reflective films, and they are still continuing; however, on the other hand, the ASTM standard is more like a product catalog about retroreflective materials, and It is not a standard that helps understand the application methods and issues of reflective film because driver performance and needs were not considered when ASTM originally classified these materials.

For this reason, in order to provide more effective technical support and guidance to their own transportation engineering construction units, developed countries in the world have specially set up their own national technical standards instead of directly using ASTM. Classification of reflective materials.

Reflective film is a layer structure composed of multiple layers of materials with different properties. Different reflective films have different layer structures. Figure 3 is the basic structural diagram of the earliest glass bead reflective film. It can be seen from the figure that reflective films generally consist of a surface layer (protective film), a reflective layer (functional layer), a base layer (carrying layer), and an adhesive layer. Membrane structure objects composed of multiple layers of different materials such as the bottom layer (protective layer) and the bottom layer (protective layer). The surface layer of the reflective film is generally made of a resin film with good light transmittance and weather resistance. The materials of the reflective layer vary according to different types of reflective films, including tiny glass beads, microprisms or metal reflective coatings, etc. The base layer has many It is a film made of resin organic compounds. The adhesive layer is usually epoxy resin glue, and the bottom layer is a protective layer made of thick paper.

Table 1 is a structural diagram of various reflective films. It can be seen that the types of reflective films are different, and their constituent materials and structures are also different.

Table 1 Illustration of the main structures of various reflective films. The primary function of reflective films is to improve the surface performance of traffic signs so that they can adapt to all-weather traffic needs and improve road safety operating conditions.

Due to the differences in the reflective properties of different types of reflective films, when it is specifically applied to the production of traffic signs, it is necessary to carry out corresponding specifications according to the setting function and purpose of the signs. The science of studying this application specification is regarded as an important part of traffic control and safety technology by safety engineering professionals from all over the world.

Traffic control and safety technology has been developed for hundreds of years. Since the first traffic sign standard was published in the United Kingdom in 1908, many countries around the world have continued to invest a large amount of scientific research and technology resources to analyze and master the role and value of retroreflective technology in the field of traffic safety. In this regard, those at the forefront are developed countries such as Europe and the United States. Their research results have helped China in many aspects to go from scratch to something in just over 10 years - China's transportation Research on sign reflective technology started in the late 1980s, with the national standard GB5768 for traffic signs and the national standard GB18833 for reflective materials for traffic signs as the main technical specifications. In many aspects, these standards are still in the stage of extensive improvement and development, and relevant scientific application methods and effect research conclusions require a lot of time and practice. Lens-embedded reflective film, commonly known as "engineering grade", is the first type of glass bead type reflective film. It is customary in the industry to call the "engineering grade" series of reflective films, invented in 1937. The name "Engineering Grade" comes from the registered English product name "Engineering Grade", which is the name of the company that invented the product. Later, many scientific research institutions directly used this product name to represent the name of experimental materials, so the name became a common usage in the transportation engineering community around the world. Its front brightness (0.2?/-4?) is generally below 100cd/lx/m . It was not until November 2008 that the new prism-type engineering grade reflective film (also called super engineering grade, English EGP, Engineering Grade Prismatic) developed based on the reflective brightness characteristics of engineering grade reflective film came out, and technology innovation was once again used. It breaks through and enriches the meaning of engineering grade reflective film.

The traditional engineering-grade reflective film was introduced to China in the 1980s. In the 1990s, a number of manufacturers began to appear in China to manufacture this kind of reflective film.

The adhesive backing of engineering-grade reflective film is generally divided into pressure-sensitive and heat-sensitive types, both of which can be pasted. Using the same type of ink and screen printing technology, various patterns can also be printed on it. The suitable base plate for engineering-grade reflective film is aluminum plate, and the construction operating temperature is generally required to be above 18 degrees Celsius. If the temperature is too low, it will affect the performance of the adhesive and damage the life of the sign. Figure 4 is a schematic structural diagram of the lens embedded reflective film. The service life of engineering-grade reflective film is generally 3 to 7 years. The front two degrees of white film (0.2?/-4?) is generally around 100cd/lx/m, depending on the manufacturer. Some manufacturers only provide reflective films for 7 years, and the brightness retention value after 7 years is at least 50% of the initial brightness value. Some manufacturers only provide 3-year and 5-year quality guarantees.

This is mainly caused by the different weather resistance of reflective films. Reflective films made of the same raw materials have different life spans when used under different regional climate conditions.

One thing that needs more attention is that the brightness stability, brightness intensity and weather resistance of engineering-grade reflective films are all important basis for inspecting the production quality of this type of reflective film. In these links, cutting corners in any link can reduce product costs, but its quality will also be greatly compromised, especially the gap in weather resistance and photometric parameters, which can clearly reflect the advantages and disadvantages of engineering-grade reflective films. . Lens-sealed reflective film is a durable glass bead-type reflective film, which is commonly called "high-strength" reflective film in the industry. It was successfully developed in 1972. "High-intensity grade" comes from the English High Intensive Beads (HIB for short), which was originally the special name of the company that developed the product. Until 1985, starting from Japan, companies in some countries and regions also began to produce this kind of reflective film. The term "high-strength grade" began to be used by other manufacturers one after another, and gradually became a unified name for this special structure of reflective film. Considering that most of the readers of this book are people in the industry, and the name of high-strength level has become a common name in the industry, this book starts from the perspective of easy understanding for readers. In the following chapters, "high-strength level" is also used as the main title.

This high-strength reflective film, manufactured with qualified technology and materials, has a reflective coefficient at least twice as high as that of engineering-grade reflective films. Its internal vacuum support structure also solves the problem of condensation on signs caused by temperature changes. dew problem, thereby further improving the material's reflective ability. When this material came out in the 1970s, it was successfully used to make traffic signs and saved a lot of lives in response to the needs of technological progress as vehicle speeds increased and road conditions improved. Compared with engineering-grade reflective film, high-strength reflective film makes the sign more visible even at larger angles and in bright areas, effectively warning drivers of dangerous road conditions ahead.

High-intensity reflective film uses glass bead reflective technology. Due to its innovation in product structure, it has unparalleled reflective brightness and angle performance compared to engineering-grade reflective film. But at the same time, it is also due to The high-strength grade's own structure has led to some product defects that are difficult to overcome, such as products that are brittle and easy to tear, wrinkles, bubbles, surface honeycomb protrusions, high production energy consumption, large emissions, etc. The limitations of glass bead technology also hinder the improvement of high-strength grades to higher brightness and better angles.

High-strength reflective film is also a material with adhesive backing, and is generally divided into two types: pressure-sensitive and heat-sensitive. Various patterns can be produced using screen printing technology using the same type of inks. High-intensity reflective film is generally made of a resin film with good light transmittance and weather resistance as the surface layer. The second layer is a vacuum layer, the third layer is embedded micro glass beads, the fourth layer is a metal reflective coating, and the fifth layer is resin. The load-bearing layer, the sixth layer is adhesive, and the seventh layer is the backing paper protective layer. Figure 5 is a schematic structural diagram of a high-intensity reflective film, and Figure 6 is a typical appearance of a high-intensity reflective film. High-strength reflective film is mainly used to make major traffic signs such as guide signs, prohibition signs, warning signs and instruction signs. After the advent of high-strength reflective film, the time it takes for drivers to identify traffic signs has been shortened, and the distance between signs and obstacles ahead has been significantly increased, which greatly increased the time to take safety precautions, reduced the incidence of nighttime road traffic accidents, and improved traffic safety. sex. According to empirical research, the brightness of high-strength retroreflective materials is significantly higher than that of engineering-grade retroreflective materials. Since the 1990s, this high-strength retroreflective material has been widely used on China's highways.

Since then, with the improvement of motor vehicle performance and road construction technology, the urban environment has changed dramatically, highways and high-speed vehicles have increased significantly, urban light sources have become complex, and wide roads and sharp bends have emerged in endlessly, which has put a heavy burden on drivers. There are new requirements for predicting sight distance. Some shortcomings of high-intensity reflective materials, especially in large-angle reflective performance and processing technology and cost, are no longer comparable to the emerging prism technology and are gradually beginning to be replaced.

In the second half of the 1990s, especially in the 21st century, the United States and Europe have fully launched the process of replacing high-strength materials with prism-grade materials. In particular, the "super-strength" retroreflective material that came out in 2004 uses prism technology, which is not only qualitatively improved over the high-strength grade in terms of reflective performance, processing methods, energy conservation and emission reduction, but also does not lose in terms of price and cost. Since then, the United States, the birthplace of high-strength materials, has no longer produced this material, making China the only producer of high-strength reflective materials.

The service life of high-quality high-strength reflective film is generally 10 years. The front brightness of the white film (0.2?/-4?) is generally above 250cd/lx/m. Under normal use conditions, after 10 years The brightness retention value is at least 80% of the initial brightness value. The suitable substrate for high-strength reflective film is aluminum plate, and the operating temperature is usually required to be above 18 degrees Celsius. The retroreflective principle of microprism reflective film is different from that of engineering grade (embedded lens) and high-strength grade (lens sealed) reflective film. Both engineering-grade and high-strength grade reflective films use the glass bead reflection principle, while the reflection of microprism reflective film The principle is to use the refraction and reflection of microprisms.

The main representative products of microprism reflective film can be divided into four categories in terms of retroreflective characteristics and structure: truncated prisms that focus on long-distance legibility, truncated prisms that focus on short-range and wide-angle legibility, and truncated prisms that focus on long-distance legibility. Full prisms with distance recognition performance and short-range reading performance, and new prism-type reflective films that combine these prism technologies with new material technologies. They are new reflective materials that comply with the diversification of application levels and have emerged in recent years to meet the needs of different levels.

Long-distance truncated microprism reflective film is the first generation of microprism reflective film. It was launched in the early 1980s. Its English name is Long Distance Prismatic (LDP). The first generation diamond grade, crystal grade and starlight grade are all such products. The front brightness of this type of reflective film is very high. The front brightness of white films (0.2?/-4?) is generally above 800cd/lx/m, and the distribution of retroreflective light has no directionality. Whether the reflective film is horizontal or There is not much difference in the reflective effect when applying the film vertically. However, under large incident angles and observation angles, the reflective brightness will be greatly attenuated. Figure 7 shows the structure diagram of this type of reflective film under a microscope. This kind of reflective film that highlights the brightness of the front retroreflection is more suitable for use as outline signs, warning posts, etc., but is not suitable for use as traffic signs that require more visibility within the reading distance. This early prism reflective film was a phased result of design and research and development at that time. The prism structure at that time could not solve the problem of retroreflective brightness at large observation angles.

After the first generation of microprism reflective film came out, people discovered a problem. When a motor vehicle actually drove into the reading distance of the sign, that is, at a large viewing angle, the brightness of the sign attenuated. It is so large that the content of the sign cannot be read within a reading distance, or it takes longer to read. As a result, people used the large-angle truncated microprism structure to create large-angle truncated microprism reflective films to solve the problem of maintaining two degrees of the mark within the reading distance. Therefore, this kind of large-angle reflective film is also a special prism-type reflective film described in terms of reflective performance.

Compared with the long-distance truncated microprism reflective film, the front brightness of the large-angle truncated microprism reflective film is relatively low, but at large incident angles and observation angles, its reflective brightness will not be as good. Great attenuation. The large angle corresponds to locations with multiple lanes and many curves, as well as signs with complex content that require a long reading time, so this kind of reflective film is suitable for traffic signs on urban roads and wide roads. Although its frontal reflective brightness at a long distance is average (only compared to the long-distance prism level, it is still more than twice as high as the frontal brightness of the high-intensity level), but at close range (when reading the logo content is required) distance), its reflective brightness is much higher than that of long-distance reflective film. Its directionality is stronger than that of long-distance reflective film, and it can be adjusted according to the position and direction of the sign to meet the needs of reading. Figure 8 shows the structure diagram of the VIP large-angle truncated microprism under a microscope. VIP (Visual Impact Prismatic), translated as visual impact prism, came out in the late 1980s and was once widely used. It was discontinued after the emergence of full prism technology.

Full-prism reflective film is a prism-type retroreflective material using a full-prism structure. It removes the non-reflective parts of the traditional micro-prism structure, so that the reflective film is entirely composed of prism structures that can achieve total reflection. Become. It combines the two characteristics of long-distance and large-angle microprism reflective films. While maintaining high front brightness and easy detection at long distances, it also improves the reflective brightness at large incident angles and observation angles at a distance of 50-250 meters. .

The advent of this full-prism reflective film breaks through the academic barrier that prismatic reflective films cannot take into account both long-distance and short-distance reflective capabilities. Based on the path and mode of car light propagation, it finds the angles (incident angle and observation angle) required for sign recognition within the ideal distance, then determines the non-reflective areas on the traditional truncated microprisms, and then converts these non-reflective areas into The area is removed, thereby achieving 100% of the reflective structure area per unit area of ??the reflective film, which is the so-called "total reflection".

Of course, this is only the theoretical reflective efficiency of 100%. In actual production, due to limitations of materials and other conditions, 100% of the brightness of reflective car lights cannot be achieved. Currently, the best reflection efficiency is 58%, which is much higher than other types of reflective films, such as high-intensity reflective films. Efficiency, only 23%. Moreover, from the observation angle of 0.2° to 2°, the retroreflection efficiency can always remain above 50%. Figure 9 is an electron micrograph of the full prism reflective film.

On the current full prism reflective film, after each microcrystalline cube is connected and arranged according to a certain rule, there will be more than 930 units on a square centimeter of material area to control the incidence of light. and reflected paths. The lower layer of the microcrystalline cube corner is sealed to form an air layer, which uses the diffraction phenomenon of light to form total internal reflection of the incident light, thereby achieving the best reflective effect without the need for a metal reflective layer. Compared with traditional engineering-grade and high-strength-grade reflective films, this kind of reflective film made of wear-resistant and high-hardness polycarbonate material and microcrystalline cube technology has not only doubled its reflective performance, but also has better large-angle reflective performance. Great improvement.

The front brightness of this full-prism reflective film is more than six times that of the engineering grade. The front brightness of the white film (0.2?/-4?) is generally above 600 cd/lx/m, which is more than twice that of the high-intensity grade. Large observation The retroreflective performance at angles (0.5° and 2°) is about two to four times higher.

Full prism reflective film is a traffic sign material suitable for all grades of highways and urban roads. Applications in the West have gradually replaced the investment and consumption of sign lighting. When making road signs, if we consider long-term investment benefits and safety benefits, full-prism reflective film can replace any grade of reflective film. Under normal use conditions, the retained value of full-prism reflective brightness after ten years of use is at least 80% of the initial brightness value. That is, after ten years, it can still greatly exceed the retroreflection of new high-strength and engineering-grade reflective films. Performance is a more economical choice when viewed from the perspective of scientific development. At the same time, if the same type of ink is used, combined with screen printing technology, various types of traffic signs with patterns can be produced.

Full prism reflective film is mainly used in guide signs, prohibition signs, warning signs and instruction signs, especially signs that require a long time to read, signs with complex visual environment, as well as wide roads and high-grade On the road, its performance is particularly outstanding. The suitable base plate for diamond grade reflective film is aluminum plate, and the processing operating temperature is generally required to be above 18 degrees Celsius.

Figure 10 is a comparison of the retroreflective brightness values ??of engineering-grade reflective film, high-strength grade, truncated prism and full prism at various angles. With the advancement of technology, the photometric performance of full-prism reflective films at all angles has been significantly improved.

In recent years, prismatic reflective films, without major changes in structure, have shifted the focus of innovation to achieving richer light control effects and through different material processing technologies. Rich material properties are provided to achieve different retroreflective capabilities and different flexibility to meet the needs of different levels. Reflective films commonly known as "super-strength grade", "extra-strength grade" and prismatic engineering grade (new super engineering grade) in the market are all new forms of prismatic reflective film. The truncated prism structures of these reflective films are basically the same, but the material processing techniques are different, resulting in different reflective effects, superior weather resistance and processing adaptability to cope with different application needs.

Among them, especially the super-strong reflective film, it has become popular rapidly after its advent in the early 21st century because it complied with the needs of the market. The original intention of its design is to take advantage of the prism structure, ensure that it can surpass all functions of high-strength reflective film, and also have better retroreflective performance and superior cost performance under multi-angle conditions.

These new prismatic reflective films have very high strength and thickness, which eliminate defects such as easy tearing, wrinkles, bubbles, and honeycomb protrusions on the surface of the reflective film during sign processing, greatly simplifying the difficulty of construction. , making the sign processing process easier to control and reducing losses caused by poor processing. At the same time, due to the large surface brightness factor of the reflective film, the retroreflective performance is greatly improved. It not only has a superior retroreflection coefficient at long distances, but under general visual recognition requirements, the large observation angle at close range can still maintain good brightness of the signs, allowing drivers to detect signs earlier and Read the signs more clearly at a closer distance. Figure 11 is a schematic structural diagram of these prism structure reflective films. Different retroreflective effects can be formed through differences in material processing of the resin layer and cubic crystal surface.

The surface layer of this type of reflective film is mostly made of polycarbonate material, which is not only more wear-resistant and scratch-resistant, but can also be used with screen printing inks and thermal transfer printing to produce colorful traffic signs. . At the same time, due to the increase in surface brightness factor, the signboard is more eye-catching and bright during the day, and it also has better weather resistance.

It is worth mentioning that at the 2008 Beijing Olympics, which had strict requirements on traffic signs in all aspects, the Beijing Municipal Traffic Management Bureau used this kind of reflective film to complete the preparations for the event with high quality and speed. mission, making China the first country in the history of the Olympic Games to use this kind of reflective film to make special lane prompt signs. This also shows from one aspect that China's traffic sign production technology has quickly approached the international advanced level. See Figure 12. Figure 12(a) shows the super reflective film sign being installed. The colored part above is printed by a printer. Picture (b) shows the super reflective film being printed. The most distinctive feature of the super reflective film surface is the unique stripe pattern in Figure (c). This is a feature that other reflective films do not have.

The prism-type engineering-grade reflective film, which was only launched in 2008, is also a brand-new product concept. While ensuring the front brightness performance of traditional engineering-grade reflective films, it has made great progress in large-angle reflective performance. The retroreflective ability even surpasses the parameters of high-strength reflective films. At the same time, due to the use of polycarbonate materials , making this kind of reflective film hard and highly weather-resistant, which can greatly improve construction efficiency and provide more technical options for the application and promotion of retroreflective materials.

Reflective films after the full prism structure have not yet made any structural breakthroughs. However, there is still a lot of room for development in the cost, material and chemical coating of reflective film. Fluorescent reflective film is a typical example of improving coating technology to further optimize the function of reflective film.

Fluorescent full prism reflective film is a reflective film with special optical effects that combines special fluorescent materials with excellent weather resistance (general fluorescent materials have poor weather resistance) with full prism technology. There is a unique weather-resistant fluorescent factor in the fluorescent reflective film, which can increase the activity after absorbing the energy of visible light and part of the invisible light in the spectrum, thereby converting the energy of invisible light into the energy of visible light, making the chromaticity of the reflective film and luminosity play out more powerfully during the day, thus increasing the conspicuity of the logo.

Because the fluorescent reflective film can absorb the energy of invisible light in the spectrum and convert it, it can have better chromaticity and luminosity, which is the so-called more vivid. This kind of fluorescent reflective film, under bad weather conditions and when the sun is not so strong, is much brighter than ordinary colors and is easier to attract people's attention. The use of this fluorescent reflective film in traffic safety facilities is of great significance to ensure driving safety at dawn, dusk, or in severe weather such as rain, snow, fog, etc. At present, fluorescent full-prism reflective films are widely used abroad, such as fluorescent warning signs, fluorescent linear delineators, fluorescent signs in road construction areas, etc. The yellow-green fluorescent full-prism reflective film has been approved by the US Federal Highway Administration for use in traffic signs for pedestrians, non-motor vehicles and school areas; the orange fluorescent full-prism reflective film is mostly used in construction area signs. Countries around the world have also introduced corresponding standards, specifications and technical conditions for fluorescent reflective films. Figure 13 is a comparison of fluorescent and non-fluorescent reflective films.

In China, since 2006, fluorescent yellow reflective films and fluorescent yellow-green reflective films have begun to have some applications. The Chinese traffic engineering community's detailed understanding of this new technology can be seen in the rainy and foggy section of the highway from Sichuan to Mount Emei, the accident-prone section of the Badaling Expressway in Beijing, and the Olympic-only lanes on the Fifth Ring Road in Beijing. and application play. See Figure 14 and Figure 15. Figure 14: The sidewalk warning signs near the Beijing Olympic water sports venue use fluorescent yellow-green full-prism reflective materials to improve the visual recognition of the warning signs. Pay attention to the difference in luminosity and chromaticity of warning signs using ordinary reflective film next to them. In order to ensure Olympic traffic, speed reminder equipment with fluorescent yellow-green full-prism reflective film is being installed on the Fifth Ring Road (Figure 15). It is worth noting that under backlighting, other traffic signs have poor chromaticity and luminosity, but fluorescent signs The yellow-green full-prism reflective film area is very eye-catching.

It should be noted that fluorescent reflective film is a combination of weather-resistant fluorescent factors and prism-type reflective film. Advertising materials printed with lemon yellow do not fall into this technical category, although the surface color spectrum looks close , but does not have all the technical characteristics of fluorescent reflective film.