GB2189919A

GB2189919A - Temperature sensitive reflective marker or indicator

Info

Publication number: GB2189919A
Application number: GB08610057A
Authority: GB
Inventors: Glyn Martin Dominy
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-04-24
Filing date: 1986-04-24
Publication date: 1987-11-04
Also published as: GB8610057D0

Abstract

A reflective marker or indicator which can be applied to a surface over which vehicles travel, or which can be located adjacent to such a surface, in order to give an indication of icing conditions on the surface, comprises a layer of line forming material 12, a sealer material 14 applied onto the line forming material 12, a liquid-crystal material 15 which reflects light of a particular wavelength which depends on temperature applied onto the sealer material 14, glass spheres 16 applied onto part of the liquid-crystal material 15, a U/V light shield 17 applied onto the liquid-crystal material 15 and an acrylic material 18 applied over the whole of the marker or indicator, the liquid-crystal material preferably reflecting white light when the temperature is above 0 DEG C and reflecting blue light when the temperature is at or below 0 DEG C. <IMAGE>

Description

SPECIFICATION Temperature sensitive reflective marker or indicator This invention relates to a reflective marker or indicator which can be applied to a surface, such as a road surface, over which vehicles travel, or which can be located adjacent to such a surface, and which will give an indication when icing conditions prevail on the surface.

Liquid-crystal temperature indicators are known, particularly in the field of disposable thermometers. Such indicators are formed from a cholestoric liquid-crystal material which reflect light of a particular wavelength which depends on temperature.

According to the present invention there is provided a reflective marker on indicator which can be applied to a surface over which vehicles travel, on which can be located adjacent to such a surface, said marker or indicator comprising a layer of line material, a sealer material applied onto the line material, a liquid crystal material applied onto the sealer material, glass spheres applied at least onto part of the liquid crystal material, a u/v light shield applied onto the liquid crystal material and an acrylic material applied over the whole of the marker or indicator.

Preferably the predetermined temperature is that at which water will freeze on said surface.

Thus a reflective marker or indicator according to the present invention will give an indication to the occupants of vehicles that icing conditions prevail on the surface. Such an indication is desirable when black ice, which can not be readily seen, forms on the surface.

An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a reflective line marker according to the present invention, and Figure 2 is a longitudinal section through the marker taken along the line 2-2 indicated on Fig. 1.

The reflective marker is rectangular in plan view and is divided into an area 10 which is black and an area 11 which is white. The marker consists of a strip of line material 12 which can be applied either directly to the road surface or to a carrier from which the marker when completed can be lifted and later applied to a road surface.

Half of the strip of white line material 10 is coated with a black paint 13 over the area 10. A sealer material 14 which is preferably a PVA adhesive is then applied over the whole surface. A liquid-crystal material 1 5 is then applied on top of the sealer material 14. Glass sphere 16 are then applied on top of the material 15 only over the area corresponding to area 11. A material 17 constituting a u/v light shield is then applied over the whole length of the strips and an acrylic material 18 is then applied over the layer of material 17.

When the surface on which the reflective marker is applied is subjected to temperatures at or below freezing, the liquid-crystal material 15 reflects light of a particular wavelength which is different to that which it reflects when the temperature is above freezing. Preferably the liquid-crystal material 15 reflects a wavelength giving the colour blue when the temperature is at or below freezing and reflects a wavelength giving a white colour when the temperature is above freezing. Thus during daylight when the temperature is above freezing the area 10 is black and the area 11 is white. When the temperature fails to or below freezing the liquid-crystal material 15 turns blue and thus the area 10 appears blue but the area 11 still appear white even though the liquid-crystal material 15 in that area has changed colour.

During darnkess when the temperature is above freezing the area 10 is black and the area 11 is white and the white is reflected by the glass sphere 16 when in the range of the vehicles headlights. When the temperature is at or below freezing the liquid-crystal material 15 turns blue and this is reflected by the glass sphere 16 back to the driver.

Thus, during daylight and during darkness the reflective marker will indicate icing conditions to a road user.

The reflective marker can be incorporated into a line provided on a road surface or incorporated into lettering provided on a road surface.

The reflective marker can be provided on a surface other than a road, such as an airport runway or aircraft turning area.

Instead of the marker being provided on the road surface it may be provided at the side of the road or adjacent to the road. For example the marker may be provided on kerb stones at the side of the road surface.

The marker may be circular or of any other shape in plan view instead of being rectangular.

The liquid-crystal material is preferably a thermochromic micro encapsulated liquid crystal sold as TCC 409 by B D H Chemicals Ltd.

Preferably the liquid-crystal material goes blue at 1" to 1.5 .

1. A reflective marker or indicator which can be applied to a surface over which vehicles travel, or which can be located adjacent to such a surface, said marker or indicator comprising a layer of line forming material, a sealer material applied onto the line forming material, a liquid-crystal material which reflects light of a particular wavelength which depends on temperature applied onto the sealer ma

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Temperature sensitive reflective marker or indicator This invention relates to a reflective marker or indicator which can be applied to a surface, such as a road surface, over which vehicles travel, or which can be located adjacent to such a surface, and which will give an indication when icing conditions prevail on the surface. Liquid-crystal temperature indicators are known, particularly in the field of disposable thermometers. Such indicators are formed from a cholestoric liquid-crystal material which reflect light of a particular wavelength which depends on temperature. According to the present invention there is provided a reflective marker on indicator which can be applied to a surface over which vehicles travel, on which can be located adjacent to such a surface, said marker or indicator comprising a layer of line material, a sealer material applied onto the line material, a liquid crystal material applied onto the sealer material, glass spheres applied at least onto part of the liquid crystal material, a u/v light shield applied onto the liquid crystal material and an acrylic material applied over the whole of the marker or indicator. Preferably the predetermined temperature is that at which water will freeze on said surface. Thus a reflective marker or indicator according to the present invention will give an indication to the occupants of vehicles that icing conditions prevail on the surface. Such an indication is desirable when black ice, which can not be readily seen, forms on the surface. An embodiment of the invention will now be described, by way of an example, with reference to the accompanying drawings, in which: Figure 1 is a plan view of a reflective line marker according to the present invention, and Figure 2 is a longitudinal section through the marker taken along the line 2-2 indicated on Fig. 1. The reflective marker is rectangular in plan view and is divided into an area 10 which is black and an area 11 which is white. The marker consists of a strip of line material 12 which can be applied either directly to the road surface or to a carrier from which the marker when completed can be lifted and later applied to a road surface. Half of the strip of white line material 10 is coated with a black paint 13 over the area 10. A sealer material 14 which is preferably a PVA adhesive is then applied over the whole surface. A liquid-crystal material 1 5 is then applied on top of the sealer material 14. Glass sphere 16 are then applied on top of the material 15 only over the area corresponding to area 11. A material 17 constituting a u/v light shield is then applied over the whole length of the strips and an acrylic material 18 is then applied over the layer of material 17. When the surface on which the reflective marker is applied is subjected to temperatures at or below freezing, the liquid-crystal material 15 reflects light of a particular wavelength which is different to that which it reflects when the temperature is above freezing. Preferably the liquid-crystal material 15 reflects a wavelength giving the colour blue when the temperature is at or below freezing and reflects a wavelength giving a white colour when the temperature is above freezing. Thus during daylight when the temperature is above freezing the area 10 is black and the area 11 is white. When the temperature fails to or below freezing the liquid-crystal material 15 turns blue and thus the area 10 appears blue but the area 11 still appear white even though the liquid-crystal material 15 in that area has changed colour. During darnkess when the temperature is above freezing the area 10 is black and the area 11 is white and the white is reflected by the glass sphere 16 when in the range of the vehicles headlights. When the temperature is at or below freezing the liquid-crystal material 15 turns blue and this is reflected by the glass sphere 16 back to the driver. Thus, during daylight and during darkness the reflective marker will indicate icing conditions to a road user. The reflective marker can be incorporated into a line provided on a road surface or incorporated into lettering provided on a road surface. The reflective marker can be provided on a surface other than a road, such as an airport runway or aircraft turning area. Instead of the marker being provided on the road surface it may be provided at the side of the road or adjacent to the road. For example the marker may be provided on kerb stones at the side of the road surface. The marker may be circular or of any other shape in plan view instead of being rectangular. The liquid-crystal material is preferably a thermochromic micro encapsulated liquid crystal sold as TCC 409 by B D H Chemicals Ltd. Preferably the liquid-crystal material goes blue at 1" to 1.5 . CLAIMS

1. A reflective marker or indicator which can be applied to a surface over which vehicles travel, or which can be located adjacent to such a surface, said marker or indicator comprising a layer of line forming material, a sealer material applied onto the line forming material, a liquid-crystal material which reflects light of a particular wavelength which depends on temperature applied onto the sealer ma terial, glass spheres applied at least onto part of the liquid-crystal material, a U/V light shield applied onto the liquid-crystal material and an acrylic material applied over the whole of the marker or indicator.

2. A reflective marker or indicator as claimed in claim 1, in which the wavelength changes at a temperature at which water will freeze on said surface.

3. A reflective marker or indicator as claimed in claim 1 or claim 2, in which the liquid-crystal material reflects a wavelength giving a blue colour when the temperature is at or below 0 C and reflects a wavelength giving a white colour when the temperature is above 0 C.

4. A reflective marker or indicator as claimed in any preceding claim, in which a layer of black paint or the like is applied to part of the surface of the line forming material.

5. A reflective marker or indicator as claimed in any preceding claim, in which the marker is initially applied to a carrier from which it is removed before being applied to said surface or a surface located adjacent to said surface.

6. A reflective marker or indicator as claimed in any preceding claim, in which the marker or indicator is incorporated into a line provided on said surface.

7. A reflective marker or indicator as claimed in any one of claims 1 to 6, in which the marker or indicator is incorporated in lettering provided on said surface.

8. A reflective marker or indicator as claimed in any preceding claim, in which the liquid-crystal material comprises a thermochronic micro encapsulated liquid-crystal.

9. A reflective marker or indicator which can be applied to a surface over which vehicles travel, or which can be located adjacent to such a surface, substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.