WO1984000231A1 - Reflecteur de lumiere sensible a la temperature notamment avertisseur de verglas en circulation routiere - Google Patents

Reflecteur de lumiere sensible a la temperature notamment avertisseur de verglas en circulation routiere Download PDF

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Publication number
WO1984000231A1
WO1984000231A1 PCT/DE1982/000233 DE8200233W WO8400231A1 WO 1984000231 A1 WO1984000231 A1 WO 1984000231A1 DE 8200233 W DE8200233 W DE 8200233W WO 8400231 A1 WO8400231 A1 WO 8400231A1
Authority
WO
WIPO (PCT)
Prior art keywords
light reflector
light
reflector according
temperature
cell
Prior art date
Application number
PCT/DE1982/000233
Other languages
German (de)
English (en)
Inventor
Walter Ries
Gerhard Meier
Original Assignee
Meier Hans Ulrich
Walter Ries
Gerhard Meier
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
Priority claimed from DE19823224451 external-priority patent/DE3224451A1/de
Application filed by Meier Hans Ulrich, Walter Ries, Gerhard Meier filed Critical Meier Hans Ulrich
Publication of WO1984000231A1 publication Critical patent/WO1984000231A1/fr

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Classifications

    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B19/00—Alarms responsive to two or more different undesired or abnormal conditions, e.g. burglary and fire, abnormal temperature and abnormal rate of flow
    • G08B19/02—Alarm responsive to formation or anticipated formation of ice
    • 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
    • E01F9/40—Arrangements responsive to adverse atmospheric conditions, e.g. to signal icy roads or to automatically illuminate in fog; Arrangements characterised by heating or drying means

Definitions

  • Temperature-dependent light reflector especially for warning of slippage in road traffic
  • the invention relates to a temperature-dependent reflector light 10, in particular for roads! Such and light signs according to the preamble of claim 1.
  • a light reflector changes the intensity or the color of the light reflected by the arrangement depending on the temperature.
  • the European patent application 80103061.0 publication number 22 917, has disclosed a street pole for carrying one or more reflectors, which discloses the idea that the reflectors should be made from one
  • the invention is based on the object of realizing the above idea of temperature-dependent light reflectors, in particular for warning of black ice in road traffic, on the basis of liquid crystals which have the property that their optical behavior, depending on the material, is strongly temperature-dependent is and changes suddenly, especially at the clearing point.
  • the invention is therefore intended to show a simple and economically practicable route which, by means of 5 liquid crystals, leads to a temperature-dependent light reflector which can also be easily produced as a mass article,
  • OMPI 1 which causes a change in the color and / or the intensity of the light reflected by the reflectors at a certain temperature.
  • the light reflector should thus assume at least two different states
  • the light reflector can assume more than two states, in particular three states.
  • the optical liquid crystal 1 cell 1 e was already described by C. Mauguin in 1911 (Bull. Soc. Franc. Miner. Vol. 34, P. 71, 1911). It consists of two transparent plates, between which there is a liquid crystal layer such that the liquid crystal has a helical structure (e.g. rotation by 90) with respect to the layer plane. Such twisting is achieved by suitable pretreatment of the plate surfaces.
  • the liquid crystal consists, for example, of a nematic phase which, when heated above a certain temperature T, changes into a normal (isotropic) liquid phase. Nematic liquid crystals have a parallel structure, i.e. In the unaffected state, their molecules are parallel to a preferred direction.
  • the twisting in the cell arises in that the molecules assume the preferred orientation given on the surface of the plate parallel to the surface.
  • the liquid crystal stall can also be of the cholesteric type, which has a natural twist. They are also electrically switchable liquid crystals! known, e.g. be used when displaying digits in electronic watches. Such electrically switchable liquid
  • OMPI - Crystals do not play a role here, since the temperature change should be displayed without any auxiliary energy.
  • Direction of polarization by a certain angle e.g.
  • reflectors can be constructed according to the invention which change their reflection properties (color, intensity) at a certain clarification temperature T, i.e. two can assume different states.
  • a temperature-dependent optical filter eg sol-gel filter or dispersion filter
  • a light reflector according to the invention can also be built up can assume three different states depending on the temperature, which can be particularly advantageous for black ice warning in road traffic.
  • FIG. 2 shows a cross section through a reflector according to the invention with color switching at the clarification temperature T, also for Z-Vei different states;
  • FIG. 3 shows a cross section through a reflector according to the invention similar to that of FIG. 1 for three different states;
  • FIG. 4 shows a cross section through a reflector according to the invention similar to that according to FIG. 2 for three different states
  • Figure 5 shows another reflector according to the invention for three different states.
  • the light (e.g. from a car headlight) is first linearly polarized by a polarizer 1.
  • a polarizer 1 When passing through the Maugui n cell 1 e 2, depending on the temperature T, the plane of polarization of the light either remains unchanged (T y T) or it is rotated by 90 ° (TT).
  • a second polarizer 3 whose polarization direction is perpendicular to that of the first, absorbs the unchanged light while letting the light through 90 ° pass.
  • the continuous light strikes the reflecting element 4, is reflected there, passes through the polarizer-cell combination a second time and steps in the direction of the
  • This reflector arrangement thus reflects light when the temperature is below the temperature r T, while at temperatures above 1 no light is reflected.
  • a color filter can be switched on at any suitable point in the beam path of the layer combination according to FIG. 1.
  • the reflector 4 can also be specially colored in order to reflect a colored light.
  • Fig. 2 differs from that just described
  • Element 5 will generally be a birefringent plate or sheet oriented so that the optical axis forms an angle of 45 ° with the vertical.
  • This element acts as an optical delay element in that the light is split into two mutually perpendicularly polarized partial beams which suffer different delays due to the birefringence of the element. These partial beams are reassembled in polarizer 3. Since the optical path length difference of the two beams strongly depends on the wavelength of the light, the light emerging from the polarizer 3 and striking the reflecting element 4 is colored. The color can be selected by the thickness and birefringence of the element 5.
  • the transmitted color for temperatures T "T is complementary to the color for ⁇ T.
  • the light passes through the arrangement a second time and emerges again in the direction of the light source.
  • This reflector arrangement thus reflects the light in different ways colors, depending on whether the temperature is above or below T.
  • the element 5 either before or after the remplissigk istallschich 't lying birefringent may together with the adjacent thereto lying polarizer 1 and 3 by a known per se pl eochroi table selectively absorbing element (selective polarizer) to be replaced.
  • the light reflector according to the invention is particularly suitable, for example, for warning of black ice in road traffic.
  • a carrier can be provided with one or more of the light reflectors according to the invention.
  • the reflective element 4 is advantageous to design the reflective element 4 as a retroreflector so that the incident light from a car headlight is reflected back again with high intensity in the same direction.
  • the carrier can be, for example, a road pole.
  • a erfi ndungsgemä 'SSER reflector in addition to the reflector or reflectors herotrom ⁇ mlichen in the immediate soil näh * s angeo dnet are.
  • the carrier can also be, for example, a relatively short rubber elastic lobe, which is used for
  • Marking of road guidance lines is arranged in a plurality at short intervals along road guidance lines directly on the roadway and thus carries at least one light reflector according to the invention in the immediate vicinity of the ground.
  • Such rubber-elastic rags are known as carriers for conventional cat eyes and can be run over by a vehicle without damaging it.
  • the carrier can also be, for example, a half-shell-shaped or hemispherical component which is firmly connected to the roadway and rises only slightly above the roadway level, so that a vehicle can drive over it without damage.
  • At least one light reflector according to the invention is located on a free visible surface of the half-shell shaped carrier facing the road user. It is clear that the invention is not limited to attachment to certain supports.
  • the reflector according to the invention for warning of black ice cannot be attached in the immediate vicinity of the ground of a roadway in order to indicate floor temperatures which are dangerous for ice, it is advantageous to use a metallic reflector Connect ladder to the floor.
  • a metallic reflector Connect ladder to the floor.
  • It is preferably a metal strip or metal strip with good thermal conductivity, for example copper.
  • It can be the metal band or the metal ⁇ fen strei also forms excluded foil-like thin.
  • the reflectors according to the invention can also be used in addition to or instead of the conventional reflectors on roads! be attached, taking into account the road surface temperature.
  • the present invention has compared to other methods for ice warning in road traffic, among others. above all the following advantages:
  • the warning can be switched from non-reflective to reflective or from one
  • the switchover is not gradual, but at a sharply defined temperature T (within a few tenths of a degree), which can be set by selecting the liquid crystal material.
  • the layer thickness of the liquid crystal between thin parallel glass or f! üssigkri stal 1 -resistant plastic sheets can be freely selected within wide limits.
  • the light reflector according to the invention is advantageously sandwich-like.
  • the polarizers 1 and 3 made of thin film sections can be glued on, for example, so that the liquid crystal forms a structural unit with the two polarizers according to FIG. 1.
  • the polarizer 1 coming to the outside can be coated on its outer layer with a translucent protective film or the like.
  • the light reflector unit can, for example, be glued to a thin reflector plate or the like.
  • the light reflector assembly can also be supplemented by a birefringent element 5 in the form of a thin plate or film according to FIG. 2. It is clear that the light reflector assemblies can also have two liquid crystals according to FIGS. 3 and 4 or, according to FIG. 5, are provided with a temperature-dependent filter in the form of a thin plate or film.
  • the light reflector according to the invention is advantageously arranged in the immediate vicinity of the road surface.
  • a multitude of refector carriers are available to the person skilled in the art.
  • a copper foil is preferably used as the temperature bridge.
  • FIG. 3 shows an embodiment with two Maugui n cell 1 s 2 1 and 2 ", between which a polarizer 3 'is arranged .
  • - Dami t - ⁇ is the Mauguin cell 2 in Fig. 1 by the two Mauguin ⁇ Cells 2 'and 2 "and an intermediate polarizer 3' replaced.
  • FIG. 4 shows a further embodiment with two Maugui n cells 1 '2' and 2 ", between which a birefringent element 5 'and a polarizer 3' are arranged.
  • the Mauguin cell 2 in FIG. 2 is through replaced the two Mauguin cells 2 'and 2 "with the interposed birefringent element 5' and polarizer 3 '.
  • the latter can also be replaced by a selective polarizer.
  • Filters to the arrangement according to FIG. 1 or FIG. 2 overlap the transmission properties of the filter and the reflection properties of the arrangement, so that - similar to the arrangement with a double cell just described - there are three different areas when the point of change of the filter is at a temperature different from T.
  • FIG. 5 shows an embodiment in which an optical filter 6 (sol-gel filter or dispersion filter) is arranged in front of the polarizer 1 according to FIG. 2.
  • the optical filter 6 can also be connected upstream of the polarizer 1 in FIG. 1.
  • the light reflector indicates more than three color or intensity states
  • several Maugui n cells can be provided, each with an interposed polarizer.

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  • Life Sciences & Earth Sciences (AREA)
  • Atmospheric Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Polarising Elements (AREA)

Abstract

Un réflecteur de lumière sensible à la température est constitué par un élément réfléchissant (4) par exemple un rétroréflecteur devant lequel est disposée une cellule à cristaux liquides (2) selon Mauguin se trouvant entre deux polariseurs (1, 3). Entre la cellule (2) et l'un ou l'autre des polariseurs on peut encore insérer un élément biréfringent (5). Le réflecteur modifie l'intensité ou la couleur de la lumière qu'il renvoie en fonction de la température et convient notamment comme avertisseur de verglas. Le réflecteur peut par exemple être solidarisé à un poteau de signalisation, à un panneau de signalisation ou à un indicateur de traffic situé directement au sol ou au voisinage de la chaussée. Pour indiquer trois états dépendant de la température on pourra aménager une cellule double constituée de deux cellules juxtaposées de Mauguin (2', 2'') avec un polariseur intercalé (3' respectivement 5, 3'). Ou bien, on pourra ajouter un élément optique sensible à la température (Filtre sol-gel ou filtre à dispersion).
PCT/DE1982/000233 1982-06-30 1982-12-22 Reflecteur de lumiere sensible a la temperature notamment avertisseur de verglas en circulation routiere WO1984000231A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19823224451 DE3224451A1 (de) 1981-06-30 1982-06-30 Temperaturabhaengiger lichtreflektor, insbesondere zur glatteiswarnung im strassenverkehr

Publications (1)

Publication Number Publication Date
WO1984000231A1 true WO1984000231A1 (fr) 1984-01-19

Family

ID=6167244

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/DE1982/000233 WO1984000231A1 (fr) 1982-06-30 1982-12-22 Reflecteur de lumiere sensible a la temperature notamment avertisseur de verglas en circulation routiere

Country Status (2)

Country Link
EP (1) EP0113350A1 (fr)
WO (1) WO1984000231A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1063356A1 (fr) * 1999-06-23 2000-12-27 B.V. Nederland Haarlem Traffic, Parking & Industry Marquage routier
GB2487982A (en) * 2011-02-12 2012-08-15 Blaine Leathem Temperature Sensitive Road Marking

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1956287A1 (de) * 1968-12-03 1971-05-13 Basf Ag Rueckstrahler fuer Verkehrszwecke als Glatteiswarnvorrichtung
DE2940205A1 (de) * 1979-10-04 1981-04-16 Karl-Gottfried Dr. 7000 Stuttgart Reinsch Vorrichtung zum warnen vor eisglaettegefahr
EP0033525A2 (fr) * 1980-01-31 1981-08-12 Wolfgang Weiler Dispositif indicateur de la température de chaussées

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1956287A1 (de) * 1968-12-03 1971-05-13 Basf Ag Rueckstrahler fuer Verkehrszwecke als Glatteiswarnvorrichtung
DE2940205A1 (de) * 1979-10-04 1981-04-16 Karl-Gottfried Dr. 7000 Stuttgart Reinsch Vorrichtung zum warnen vor eisglaettegefahr
EP0033525A2 (fr) * 1980-01-31 1981-08-12 Wolfgang Weiler Dispositif indicateur de la température de chaussées

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Bull. Soc. Franc. Miner. Vol. 34, 1911, MAUGUIN: "Sur les Cristaux Liguides de Lehmann", pages 71-117, see page 71, last paragraph - page 72, paragraph 5 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1063356A1 (fr) * 1999-06-23 2000-12-27 B.V. Nederland Haarlem Traffic, Parking & Industry Marquage routier
GB2487982A (en) * 2011-02-12 2012-08-15 Blaine Leathem Temperature Sensitive Road Marking

Also Published As

Publication number Publication date
EP0113350A1 (fr) 1984-07-18

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