AU735376B2 - Improved signs - Google Patents

Description

WO 98/47129 PCT/AU98/00257 1 IMPROVED SIGNS This invention relates to signs and in particular to signs of a type which are intended to be used along the sides of roads so that they will be useful both during the day by reason of incidental illumination, and during the night by reason of reflection from vehicle headlights.

One of the problems applicable to this application is the difficulty of matching the effectiveness of the sign at night with the effectiveness of the sign during the day.

In order to get effective brightness from a sign from side illumination of the 1 0 headlights of a motor vehicle, there needs to be a prismatic lens effect available so that light originating from the vehicle will predominantly be directed specifically back in the direction of the originating light.

This effect is well known and is used in a number of applications applicable to roads at the present time for instance this effect is used in cats eyes in the 1 5 middle of the road and in rear and front reflectors used for signalling purposes.

For advertising signs however the difficulty is to establish an arrangement whereby any image that is a part of the sign will be effective in both types of lighting that is when there is simply incidental lighting as compared to directed lighting from a car head light.

The problem is very complex indeed.

While it is relatively easy to get an image that is at least recognisable as being the same image both for incident lighting and night time direct lighting, in many experiments conducted thus far, it has been difficult to find techniques that provide for superior appeal for the same image both during the day and at night in these situations.

An understanding of the problem perhaps will be better gained by an illustration where for instance the image is of an orange which is intended to attract the casual observer by reason of its mouth watering appeal.

WO 98/47129 PCT/AU98/00257 2 During the day, the subtlety of the orange colour has to be achieved by incidental light reflecting from the surface of the toned image whereas at night, the same effect has to be achieved by having the light first pass fully through the image a first time, be reflected from the prismatic back, and then pass once again through the same or similar parts of the image to then be seen by the viewer.

The viewer will then see in part, a first reflection by reason of some incidental light, and then the remainder of the image will be visible because of the reflected light having passed twice through the image.

1 0 One of the significant problems then is also to ensure that there is sufficient light left after the light passes twice though the image.

Sheet material providing very high reflectivity by reason of this prismatic effect is available but it is very expensive indeed and has not therefore been considered to be a useful material in a commercial sense for this application.

1 5 It also has previously not been considered that a sign should be separable from the reflective backing material.

According to this invention then there is proposed a sign having a prismatic lens reflective sheeting supported and positioned to be a reflective backing for the sign and an image carrying sheet and/or sheets separable from the reflective sheeting, positioned and supported to be in front of the reflecting face of the reflective sheeting and being such as to allow light to pass through the image carrying sheet and/or sheets to then be reflected by the reflective sheeting back along an incoming direction.

In preference at least one of the image carrying sheets is a separate transparent sheet and is positioned so that its rear side is in very close vicinity of a front surface of the reflective sheeting.

In preference the separate image carrying sheet is held by means holding the sheet with the image to have its rear side in contact with a reflective sheet.

The reflective sheet of which we talk is a very high performance material 3 0 because it is this type of material that is expensive but also it is this type of WO 98/47129 PCT/AU98/00257 3 material that provides the effective reflectivity to an efficiency that assists significantly in the visual effect of a sign.

In conjunction with the above however the separable sheet carries the image in the form either of an image applied to one or both front and rear surfaces of the sheet and wherein at least a substantial proportion of the image is comprised of an ink or inks which allow a significant proportion of light to pass therethrough.

In preference, the inks from which the image is printed are transparent inks.

In preference, the images are printed using the technique of four colour 1 0 printing wherein the effect of the image is achieved by a selection of separate dots which are placed on the surface either singularly or in partially or fully overlapping relationship to provide for an effect of the visual image.

One of the earlier problems described relates to the difficulty of matching both daylight and night time visual effect of an image with a reflective surface.

1 5 If the total criteria for the printing process especially with the four colour printing process are chosen so as to provide a good effect during the day, then there is a significant difference in the image effect at night using high reflective sheeting.

A further difficulty is that using a very high efficiency prismatic lens reflective sheeting such as that sold by 3M as "visual impact performance reflective sheeting series 3990", this is not of itself during daylight hours an apparent white colour.

That is, during night, its reflective effect does show as a substantially white colour but not so during the day.

It has been discovered that if a very light screen of white is printed across the side of the image closest to the reflective surface, then this has the effect of providing for a significant whitening of the apparent background during daylight hours or during incidental lighting and any reduction in the effectiveness of the reflective lighting at night is not observably significant.

WO 98/47129 PCT/AU98/00257 4 In preference, a white coating in the range of from 1% to 10% coverage is useful and in preference 5% is found to be very good to achieve this effect.

Further, in preference, by using a four colour process and using a coarser dot structure than is conventional for instance a resolution of in the range from screen to 45 screen has been found to improve the effect and achieve a more balanced comparison between daylight and night time usage.

A number of advantages arise by firstly separating the highly efficient prismatic lens reflective sheeting material from the material on which the image is based.

For instance, this means that the image can be replaced on a regular basis at a relatively low cost without having to replace the prismatic lens reflective sheeting material at the very significantly higher cost.

In preference, a sheet of transparent material on which an image is printed, has the image printed on a rear face so that the dot structure of the image in 1 5 the event that a four colour printing process is used, is as close as possible to the reflective sheeting.

In preference, the light white screen is printed on the rearward side of the existing image.

In a further preferred example there is an arrangement in which the image is placed on the surface of a transparent sheet which is caused to be removably adhering to the face of the reflective surface either directly or through an intermediary sheet or sheets which is or are themselves caused to be removably adhering one to the other In a further preferred example there is included an arrangement where the image is applied directly to a clear sheet which includes a clear adhesive of a type which provides for adhesion to the surface of the reflective material and allows for subsequent non damaging removal or separation of the clear sheet from the surface of the reflective backing.

These further examples have the advantages of ensuring during use that the 3 0 image is kept very close to the reflective surface but allow for recovery of the WO 98/47129 PCT/AU98/00257 reflective material at any time for further use with additional or further images on clear sheet by stripping the adhering surface away from the other surface.

The type of clear film or sheet material that can be used is chosen to be appropriate for the application and is such as to hold a printed image.

In conjunction with the above however the separable sheet whether separable by reason of the type of adhesive or otherwise carries the image in the form either of an image applied to one or both front and rear surfaces of the sheet and wherein at least a substantial proportion of the image is comprised of an ink or inks which allow a significant proportion of light to pass therethrough.

1 0 In preference, such inks are transparent.

In preference, the images are printed using the technique of four colour printing wherein the effect of the image is achieved by a selection of separate dots which are placed on the surface either singularly or in partially or fully overlapping relationship to provide for an effect of the visual image.

1 5 In relation to the above it is also of value to provide a light screen of white which is printed across the side of the sheet carrying the image which side is closest to the reflective surface. This has the effect of providing for a significant whitening of an apparent background during daylight hours or during incidental lighting and any reduction in the effectiveness of the reflective lighting at night is not observably significant.

The sheet has a clear adhesive which is selected such that the adhesive will not substantially affect the transparency of the image but will allow for substantial adhesion through substantial changes of temperature and humidity but is also removable by simple pulling from one corner so that it will progressively separate.

For a better understanding of this invention it will now be described with relation to embodiments which shall be described with the assistance of the drawing where: Figure 1 is a cross sectional view of a part of a sign constructed in accord with the embodiment.

WO 98/47129 PCT/AU98/00257 6 Referring specifically to the drawing and further, describing the embodiments there is provided in relation to the first embodiment a frame 1 including a backing sheet 2 and a front peripheral frame member 3 which has immediately behind it a foam pad 4 which also extends around the periphery of the frame 1.

The top of the frame 1 at 5 is open so that the three sheets that is a front cover sheet 6, an image carrying sheet 7 and a prismatic lens reflective sheeting 8 can each be separately slipped into position or removed from the frame 1.

In each case however when they are in position by reason of the extent of the 1 0 foam pad material 4, they are pressed at the perimeter to be together and by reason of their selected thickness and character are each sufficiently rigid across their width and length to hold themselves in a closely adjoining relationship as shown in the drawing.

The prismatic lens reflective sheeting 8 consists of prismatic lenses that are 1 5 formed in a transparent, synthetic resin which is sealed.

This is a some what white material to provide for a very high efficiency retro reflection effect.

Characteristics of the material selected which is a commercially available material available from 3M under product identification 3990 is as follows: WO 98/47129 PCT/AU98/00257 7 TABLE B1 MINIMUM COEFFICIENT OF RETROREFLECTION RA for new sheeting (Candelas/Foot Candle/Square Foot) 00 Orientation Entrance Angle Observation Angle 0 .2 .33 .5 1 White 430 300 250 300 Entrance Angle Observation Angle 0 .2 .33 .5 1 White 235 150 170 900 Orientation 400 Entrance Angle Observation Angle 0 .2 .33 .5 1 White 150 85 35 Observation (Divergence) Angle The angle between the illumination axis and the observation axis.

Entrance (Incidence) Angle The angle from the illumination axis to the retroreflective axis. The retroreflective axis is an axis perpendicular to the retroreflective surface.

The image carrying sheet 7 has an image which is shown as a dotted line at 9 but in this case is comprised of 5 layers of printing a first four of these being a printing of an image in accordance with the four colour process printing which is applied to the rear surface of a clear polyvinyl chloride sheet and then a fifth coating is applied subsequent to the application of the four colour process, this 3 5 fifth colour being white and being comprised of a white line colour at intensity that is to say the dots cover 5% of the covered area across the full back of the sheet and across the existing image.

This then describes a first embodiment.

WO 98/47129 PCT/AU98/00257 8 In relation to a second embodiment, the light white coating is applied only to selected areas namely those that are either behind effectively clear or only very lightly covered parts of an image and in each case of 5% intensity.

In a third embodiment, the image carrying sheet is a sheet of plastics material which has applied over the image applied to an inner side, a contact adhesive which when pushed against the front face of the reflective sheet will adhere thereto and will be held in intimate contact thereby. This further has the advantage that there will be a minimal gap between the reflective elements in the reflective sheet and the image elements. This has the further advantage 1 0 that there will be a minimum of offset and therefore loss of reflected image intensity in some cases.

Further however, the adhesive chosen is also chosen to allow for easy and quick removal in a non destructive way of the image carrying sheet from the reflective surface.

This facilitates recovery of the exspensive high grade reflective material and makes it easy to change the image from time to time for appropriate commercial purposes.

In a further embodiment the image carrying sheet is a plastics material that will be attracted and adhere by reason of electrostatic attraction. This is less attractive where the sign may be vulnerable to easy access by less desirable elements and it will be dependent on the atmospheric conditions maintaining sufficient attraction but it is highly desirable from the point of view of cost, ease of application and removal and long term stability where chemical adhesives may deteriate over time.

In a further embodiment, the image is formed by being cut from transparent coloured sheeting where each element of the image is then secured in a removable fashion either to a clear transparent support sheet which is then held against the surface of the prismatic lens reflective sheeting or the elements are each held by adhesive directly against the surface of the 3 0 prismatic lens reflective sheeting.

In a further embodiment, the image is applied to a clear transparent sheet by a four colour printing process. This sheet is then held against the surface of the WO 98/47129 PCT/AU98/00257 9 prismatic lens reflective sheeting.

As will be seen therefore the printing can be varied although different printing techniques provide varied effects which can be of different benefit. For instance, digital printing can also be used.

Generally from the above it will now be seen that the proposal provides significant advantages to those who currently are seeking additional signage that can be viewed in an attractive way but at a reasonable cost.

The use of removable image carryingsheets with high efficiency reflective material has transformed the economics in this industry and has opened up a 1 0 significant new market for available signage.

Claims (16)

1. A sign having a prismatic lens reflective sheeting supported and positioned to be a reflective backing for the sign and an image carrying sheet and/or sheets separable from the reflective sheeting, positioned and supported to be in front of the reflecting face of the reflective sheeting and being such as to allow light to pass through the image carrying sheet and/or sheets to then be reflected by the reflective sheeting back along an incoming direction.

2. A sign as in claim 1 further characterised in that at least one of the 1 0 image carrying sheets is a separate transparent sheet and is positioned so that its rear side is in very close vicinity of a front surface of the reflective sheeting.

3. A sign as in the immediately preceding claim further characterised in that the separate image carrying sheet is held by means holding the sheet 1 5 with the image to have its rear side in contact with a reflective sheet.

4. A sign as in any one of the preceding claims further characterised in that the reflective sheeting is comprised of prismatic lenses that are held in alignment in a transparent, synthetic resin. A sign as in any one of the preceding claims further characterised in that the image carrying sheet carries an image in the form of an image applied to both front and rear surfaces of the sheet and wherein at least a substantial proportion of the image is comprised of an ink or inks which are transparent.

6. A sign as in any one of the preceding claims further characterised in that at least one of the images on the image carrying sheet is printed on the sheet as a four colour print wherein the image is formed by separate dots which are placed on the surface either singularly or in partially or fully overlapping relationship.

7. A sign as in any one of the preceding claims further characterised in that a light screen of white is printed across the rear side of the image. 11

8. A sign as in the immediately preceding claim further characterised in that the white coating is in the range of from 1% to 10% coverage.

9. A sign as in the immediately preceding claim further characterised in that the white coating is approximately 5% coverage. A sign as in the preceding claim 6, further characterised in that the four colour process has a dot structure in the range from 30 screen to 45 screen.

11. A sign as in any one of the preceding claims further characterised in that the image carrying sheet has the image printed on a rear face so that the dot structure of the image in the event that a four colour printing process is used, is close to front surface of the reflective sheeting.

12. A sign as in any one of the preceding claims further characterised in that the light white screen is printed on the rearward side of the image carrying sheet.

13. A sign as in any one of the preceding claims further characterised in that 15 an image is placed on the surface of a transparent sheet which is caused to be removably adhering to the face of a reflective surface either directly or through an intermediary sheet or sheets.

14. A sign as in claim 13 where the image is applied directly to a clear sheet which includes a clear adhesive of a type which provides for adhesion to the surface of the reflective material and allows for subsequent non damaging removal or separation of the clear sheet from the front surface of the reflective sheeting. 11a A sign as in any one of the preceding claims further characterised in that where the separable sheet whether separable by reason of the type of adhesive or otherwise carries the image in the form either of an image applied to one or both front and rear surfaces of the sheet and wherein at least a substantial proportion of the image is comprised of an ink or inks which allow a significant proportion of light to pass therethrough.

16. A sign as in any one of the preceding claims further characterised in that a light screen of white which is printed across the side of the sheet 4 *o 9. 5 w C *oo> *ooo *o^ oo *I WO 98/47129 PCT/AU98/00257 12 carrying the image which side is closest to the reflective surface.

17. A sign as in any one of the preceding claims further characterised in that the sheet has a clear adhesive which is selected such that the adhesive will not substantially affect the transparency of the image but provides substantial adhesion.

18. A sign as in any one of the preceding claims further characterised in that the image is comprised of an element or elements of transparent coloured sheet in the shape of the image parts each element including an adhesive inner surface.

19. A sign substantially as described in the specification with reference to and as illustrated by the accompanying illustrations. SUBSTITUTE SHEET (Rule 26)