EP0687284A1 - Fluorescent coating for road markings - Google Patents

Fluorescent coating for road markings

Info

Publication number
EP0687284A1
EP0687284A1 EP94909396A EP94909396A EP0687284A1 EP 0687284 A1 EP0687284 A1 EP 0687284A1 EP 94909396 A EP94909396 A EP 94909396A EP 94909396 A EP94909396 A EP 94909396A EP 0687284 A1 EP0687284 A1 EP 0687284A1
Authority
EP
European Patent Office
Prior art keywords
wavelength range
light
fluorescent
fluoresces
nanometers
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP94909396A
Other languages
German (de)
French (fr)
Inventor
Peder Fast
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ultralux AB
Original Assignee
Ultralux AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ultralux AB filed Critical Ultralux AB
Publication of EP0687284A1 publication Critical patent/EP0687284A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/58—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing copper, silver or gold
    • C09K11/582—Chalcogenides
    • C09K11/584—Chalcogenides with zinc or cadmium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/22—Luminous paints
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F9/00—Arrangement of road signs or traffic signals; Arrangements for enforcing caution
    • E01F9/50—Road surface markings; Kerbs or road edgings, specially adapted for alerting road users
    • E01F9/506—Road surface markings; Kerbs or road edgings, specially adapted for alerting road users characterised by the road surface marking material, e.g. comprising additives for improving friction or reflectivity; Methods of forming, installing or applying markings in, on or to road surfaces
    • E01F9/524—Reflecting elements specially adapted for incorporation in or application to road surface markings

Definitions

  • the present invention relates to a fluorescent coating which fluoresces in the presence of light within the ultraviolet wavelength range.
  • the invention relates particularly to a coating intended for road markings, for instance markings on road verges, centre line markings, stop lines, right-of-way markings, lane arrows, pedestrian crossings, and like markings.
  • the coating can also be applied to different types of signs for instance.
  • daylight paints resides in the use of a pigment which fluoresces when illuminated by ultraviolet light.
  • Swedish Patent Specification 9002413-4 describes, on the other hand, a road marking which is characterized in that the material that fluoresces when illuminated with light within the ultraviolet wavelength range is comprised of glass balls or glass pieces produced from a glass composi ⁇ tion that has been doped with a dope substance which causes the glass in the glass balls or glass pieces to fluoresce when illuminated with ultraviolet light.
  • the present invention provides a marking which can be seen better than earlier known markings.
  • the present invention thus relates to a fluorescent coating which fluoresces when illuminated with light within the ultraviolet wavelength range, said coating being intended primarily for different types of road markings and includes a material that contains a pigment for emitting one colour when illuminated with light within the visible wavelength range and material which fluoresces when illuminated with light within the ultraviolet wavelength range, and is characterized in that the material which fluoresces when illuminated with light within the ultraviolet wavelength range has been chosen to fluoresce essentially in a wavelength range of 455-555 nanometers.
  • sensitivity of the human eye varies with the wavelength of light.
  • the sensitivity of the eye also varies with different levels of illumination and whether foveal sight or peripheral sight is meant.
  • foveal sight is meant that the gaze is concentrated straight forwards, where the focus of the eye is sharpest.
  • the foveal point covers only about 0.5 degrees.
  • the perception of the eye i.e. its ability to discern an object, varies greatly with for instance the state of tiredness, the mental state, the expectation of seeing an object ahead, the stress to which the driver is subjected mentally by the surroundings, and colour content.
  • the anticipation of seeing an object is of particular interest with regard to driving a vehicle.
  • verge lines and, to some extent, verge posts are extremely high, and consequently the eye is well able to discern a verge demarcation line in relatively low contrast conditions, even in dynamic traffic.
  • the invention is based on the realization that when an edge line is produced in a fluorescent material whose fluorescence is adapted to peripheral sight and mesopic sight, the adaptation to mesopic sight will cause the gaze of the viewer to be moved further along the road, at the same time as the adaptation to peripheral sight will cause the edge line to be discerned clearly by the peripheral sight, even from close distances.
  • the material that fluoresces when illuminated with light within the ultravio ⁇ let wavelength range is chosen to fluoresce essentially in a wavelength range of 455 and 555 nanometers. This provides the aforesaid effect.
  • the fluorescent material will fluoresce in a substantially narrower wavelength range than that given above, namely between 470 and 540 nanometers.
  • the fluores- cent material is chosen so that its colour impression relating to the colour of the fluorescence within said wavelength range will lie between a blue-violet colour and a greenish colour.
  • the fluorescent material chosen is one which emits the major part of its fluorescence at a wavelength of less than 500 nanometers.
  • the fluorescent material is chosen so that it will be activated to maximum fluorescence when irradiated with ultraviolet light within the wavelength range of 340-400 nanometers, preferably within the wavelength range of 350-380 nanometers. It is namely within this wavelength range that vehicle headlamps that emit ultraviolet light provide a maximum light effect.
  • the fluorescent material In order to obtain a good effect also in daylight and at dusk, it is advantageous for the fluorescent material also to be activated by incident ultraviolet radiation that has a wavelength of about 400 nanometers.
  • incident ultraviolet radiation that has a wavelength of about 400 nanometers.
  • sub ⁇ stances which fluoresce within different wavelength ranges and which are suitable for use when practicing the inven ⁇ tion.
  • Many substances emit visible light within a given spectrum, although the major part of the visible light is found within a given wavelength range.
  • Typical fluorescent compounds or substances contain zinc sulphide (ZnS) with additives of silver (Ag) , sulphur (S) and cadmium (Cd) .
  • ZnS zinc sulphide
  • Ag silver
  • S sulphur
  • Cd cadmium

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Inorganic Chemistry (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Paints Or Removers (AREA)
  • Road Signs Or Road Markings (AREA)

Abstract

A fluorescent coating which fluoresces when illuminated with light within the ultraviolet wavelength range, wherein the coating is intended primarily for different kinds of road markings and includes material containing pigment which emits a colour when irradiated with light within the visible wavelength range and material which fluoresces when illuminated with light within the ultraviolet wavelength range. The invention is characterized in that the material that fluoresces when illuminated with light within the ultraviolet wavelength range has been chosen so that it fluoresces essentially in a wavelength range of 455-555 nanometers.

Description

FLUORESCENT COATING FOR ROAD MARKINGS
The present invention relates to a fluorescent coating which fluoresces in the presence of light within the ultraviolet wavelength range.
The invention relates particularly to a coating intended for road markings, for instance markings on road verges, centre line markings, stop lines, right-of-way markings, lane arrows, pedestrian crossings, and like markings. The coating can also be applied to different types of signs for instance.
The fact that the full beam of a car brightly illuminates the surroundings in front of the car is a generally known problem. The full beam of a vehicle will also dazzle oncoming motorists, however. When the vehicle is driven on dipped headlights, so as not to dazzle oncoming motorists, the surroundings in front of the vehicle are not illu inat- ed satisfactorily. Normally, however, the amount of light provided by dipped headlamps is sufficient for the driver to see the road ahead well enough to drive the vehicle.
However, the ability to discern objects on the road, such as road markings and other stationary markings, as well as people, is much poorer on dipped headlamps than on full beam.
One desire, which is becoming more and more pronounced, is that vehicles shall be equipped with lamps that emit ultraviolet light. Such light causes a number of different paints or pigments to fluoresce to a greater or lesser extent. It has become more general in recent times to use so-called daylight pigments or paints, i.e. paints which when illuminated by ultraviolet (UV) light emit light of visible wavelength. Light clothing also fluoresces rela¬ tively well when illuminated with ultraviolet light. If vehicles were able to transmit ultraviolet light, it would be possible to paint road verge-posts, road signs, etc., either totally or partially with so-called daylight paints to a larger extent than is now the case, with the intention of enhancing traffic safety.
It is previously known to produce road markings which fluoresce when illuminated with ultraviolet light. One such coating is known from U.S. 3,253,146. This coating is produced by mixing a pigment, which fluoresces when illuminated with ultraviolet light, with a transparent carrier or matrix.
The known technique used generally for utilizing ultravio- let fluorescent paints, so-called daylight paints, resides in the use of a pigment which fluoresces when illuminated by ultraviolet light.
Swedish Patent Specification 9002413-4 describes, on the other hand, a road marking which is characterized in that the material that fluoresces when illuminated with light within the ultraviolet wavelength range is comprised of glass balls or glass pieces produced from a glass composi¬ tion that has been doped with a dope substance which causes the glass in the glass balls or glass pieces to fluoresce when illuminated with ultraviolet light.
Tests carried out on ultraviolet fluorescing road signs have shown surprisingly that the measurements taken of the intensity of the visible light emitted from the markings do not agree with how people experience the strength of the light emitted by said markings. This means that the best fluorescent substance cannot be chosen with the aid of measuring instruments, as earlier supposed.
The present invention provides a marking which can be seen better than earlier known markings. The present invention thus relates to a fluorescent coating which fluoresces when illuminated with light within the ultraviolet wavelength range, said coating being intended primarily for different types of road markings and includes a material that contains a pigment for emitting one colour when illuminated with light within the visible wavelength range and material which fluoresces when illuminated with light within the ultraviolet wavelength range, and is characterized in that the material which fluoresces when illuminated with light within the ultraviolet wavelength range has been chosen to fluoresce essentially in a wavelength range of 455-555 nanometers.
The invention will now be described in more detail.
It is known that the sensitivity of the human eye varies with the wavelength of light. The sensitivity of the eye also varies with different levels of illumination and whether foveal sight or peripheral sight is meant. By foveal sight is meant that the gaze is concentrated straight forwards, where the focus of the eye is sharpest. The foveal point covers only about 0.5 degrees.
The sensitivity of the eye has earlier been documented and is disclosed in standard works, for instance IES Lighting Handbook, 1984, Reference Volume. This work deals with an investigation into the sensitivity of the eye in the case of foveal sight under normal lighting levels, and sight that lies outside the foveal point at normal lighting levels. Scoptic sight, i.e. the ability to see in the dark, has also been investigated and compared with photopic sight, i.e. the ability to see in normal daylight.
It has been established that the eye takes about 60 minutes to adapt fully to darkness. It has been found that none of the aforesaid cases apply when driving in the dark. This is because the eye does not become fully adapted to the dark, since this takes 60 minutes to achieve, and since the eye looks at an illumi- nated part of the road. It has been found that the eye is situated in an intermediate phase, so-called mesopic sight. The lighting levels vary between scoptic and photopic levels. Both foveal and peripheral sight are also used. Added to this is the dazzling effect of the occasional oncoming vehicle.
The perception of the eye, i.e. its ability to discern an object, varies greatly with for instance the state of tiredness, the mental state, the expectation of seeing an object ahead, the stress to which the driver is subjected mentally by the surroundings, and colour content. The anticipation of seeing an object is of particular interest with regard to driving a vehicle.
A number of tests were carried out to establish the difference between discerning a static object and discern¬ ing a dynamic traffic object. It was found that in order to discern an object in dynamic traffic, the contrast differ¬ ence required was 10-30 times higher than the contrast difference required to discern a static object.
However, expectation with regard to road markings in the form of verge lines and, to some extent, verge posts is extremely high, and consequently the eye is well able to discern a verge demarcation line in relatively low contrast conditions, even in dynamic traffic.
It has also been established that the eye is able to discern road markings at relatively low luminesce levels. It has also been established that the ability to discern fluorescent objects at low levels of illumination differs from the ability to discern non-fluorescent objects. The invention is based on the realization that when an edge line is produced in a fluorescent material whose fluorescence is adapted to peripheral sight and mesopic sight, the adaptation to mesopic sight will cause the gaze of the viewer to be moved further along the road, at the same time as the adaptation to peripheral sight will cause the edge line to be discerned clearly by the peripheral sight, even from close distances.
The fact that the gaze of the viewer is moved further along the road in combination with a high degree of expectation, causes a fluorescent edge line to be discerned clearly from much further distances than when using conventional edge lines conventional headlamps.
According to the present invention, the material that fluoresces when illuminated with light within the ultravio¬ let wavelength range is chosen to fluoresce essentially in a wavelength range of 455 and 555 nanometers. This provides the aforesaid effect.
It can be mentioned by way of example that when carrying out practical tests with a vehicle equipped with headlamps that emitted conventional visible light and ultraviolet light, the following results were obtained with regard to the distances from which the driver was able to clearly discern verge markings.
Illumination Verge Marking
Normal dipped lights Conventional
Normal dipped lights Fluorescent Normal dipped lights
+ ultraviolet light Fluorescent
Normal dipped lights Conventional Normal dipped lights Fluorescent Wet 78 Normal dipped lights + ultraviolet light Fluorescent Wet 125
It will be obvious from this Table that visibility is very greatly improved when applying the present invention.
According to one preferred embodiment, the fluorescent material will fluoresce in a substantially narrower wavelength range than that given above, namely between 470 and 540 nanometers.
According to a further preferred embodiment, the fluores- cent material is chosen so that its colour impression relating to the colour of the fluorescence within said wavelength range will lie between a blue-violet colour and a greenish colour.
When the verge lines or other markings are white, it is preferred that the fluorescent material chosen is one which emits the major part of its fluorescence at a wavelength of less than 500 nanometers.
According to another preferred embodiment, the fluorescent material is chosen so that it will be activated to maximum fluorescence when irradiated with ultraviolet light within the wavelength range of 340-400 nanometers, preferably within the wavelength range of 350-380 nanometers. It is namely within this wavelength range that vehicle headlamps that emit ultraviolet light provide a maximum light effect.
In order to obtain a good effect also in daylight and at dusk, it is advantageous for the fluorescent material also to be activated by incident ultraviolet radiation that has a wavelength of about 400 nanometers. There are a large number of commercially available sub¬ stances which fluoresce within different wavelength ranges and which are suitable for use when practicing the inven¬ tion. Many substances emit visible light within a given spectrum, although the major part of the visible light is found within a given wavelength range. The above remarks and the features set forth in the following Claims shall be read against this background.
Typical fluorescent compounds or substances contain zinc sulphide (ZnS) with additives of silver (Ag) , sulphur (S) and cadmium (Cd) . A large number of other compounds are available, and the person skilled in this art may select the compound or compounds that is/are most suited to the purpose of the present invention and to existing specifica¬ tions.
The present invention is not therefore considered to be restricted to any particular fluorescent compound or substance, but can be varied within the scope of the following Claims.

Claims

1. A fluorescent coating which fluoresces when illuminated with light within the ultraviolet wavelength range, wherein the coating is intended primarily for different kinds of road markings and includes material containing pigment which emits a colour when irradiated with light within the visible wavelength range and material which fluoresces when illuminated with light within the ultraviolet wavelength range, characterized in that the material that fluoresces when illuminated with light within the ultraviolet wavelength range has been chosen so that it fluoresces essentially in a wavelength range of 455-555 nanometers.
2. A fluorescent coating according to Claim l, character¬ ized in that the fluorescent material fluoresces substantially in a wavelength range of between 470 and 540 nanometers.
3. A fluorescent coating according to Claim 1 or 2, characterized in that the fluorescent material is chosen so that its colour impression within said wavelength range lies between a blue-violet colour and a greenish colour.
4. A fluorescent coating according to Claim 1 or 2, characterized in that when verge lines or other markings are white, the fluorescent material is chosen so that the major part of its fluorescence is emitted at a wavelength below 500 nanometers.
5. A fluorescent coating according to Claim 1, 2, 3 or 4, characterized in that the fluorescent material is chosen so that it is activated to maximum fluorescence by incident ultraviolet radiation within the wavelength range of 340- 400 nanometers, preferably within the wavelength range of 350-380 nanometers.
6. A fluorescent coating according to Claim 5, character¬ ized in that the fluorescent material is also activated by incident ultraviolet radiation having a wavelength of about 400 nanometers.
EP94909396A 1993-03-05 1994-03-04 Fluorescent coating for road markings Withdrawn EP0687284A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
SE9300741A SE511756C2 (en) 1993-03-05 1993-03-05 Fluorescent coating for road markings
SE9300741 1993-03-05
PCT/SE1994/000189 WO1994020577A1 (en) 1993-03-05 1994-03-04 Fluorescent coating for road markings

Publications (1)

Publication Number Publication Date
EP0687284A1 true EP0687284A1 (en) 1995-12-20

Family

ID=20389129

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94909396A Withdrawn EP0687284A1 (en) 1993-03-05 1994-03-04 Fluorescent coating for road markings

Country Status (4)

Country Link
EP (1) EP0687284A1 (en)
AU (1) AU6225694A (en)
SE (1) SE511756C2 (en)
WO (1) WO1994020577A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5853615A (en) * 1993-11-15 1998-12-29 Cleanosol International Ab Fluorescent covering for roads, parking areas etc, which fluoresces upon illumination with ultraviolet light
SE502005C2 (en) * 1993-11-15 1995-07-10 Cleanosol Int Ab Fluorescent coating for roads, parking lots etc that fluoresce under ultraviolet light
GB2324325A (en) * 1997-04-19 1998-10-21 Product 2000 Limited Road marking
FR2811663B1 (en) 2000-07-13 2003-05-02 Commenplus LUMINESCENT RIPING MATERIAL AND METHOD FOR PLACING SUCH MATERIAL
GB2399585A (en) * 2003-03-20 2004-09-22 Saint Gobain Pipelines Plc Surface access cover

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4208300A (en) * 1973-07-11 1980-06-17 Gravisse Philippe E Photoluminescent materials and method of manufacturing same
SE468856B (en) * 1990-07-11 1993-03-29 Ultralux Ab FLUORESCENT ROAD MARKING

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9420577A1 *

Also Published As

Publication number Publication date
WO1994020577A1 (en) 1994-09-15
SE511756C2 (en) 1999-11-22
AU6225694A (en) 1994-09-26
SE9300741D0 (en) 1993-03-05
SE9300741L (en) 1994-09-06

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