AU2008212046A1 - Illuminated sign - Google Patents

Description

00 ILLUMINATED SIGN SField of the Invention 00 The present invention relates to illuminated signs, and particularly to portable illuminated signs, such as those adapted for use on a vehicle.

Background Signs such as advertising signs are often illuminated in some way to improve 00 their visibility in low light conditions. Some of the common types of illuminated signs are: board signs lit by separate mounted or suspended incandescent bulbs directed on to the sign; "neon" signs in which the images and words of the sign are made from fluorescent tubing; and back-lit signs in which a semi-transparent panel is placed in front of a light source such as an incandescent bulb so that contrasting colours on the panel create the desired words or images.

This last type of back-lit sign is commonly used on vehicles such as taxis. The sign is used to indicate that the vehicle is a taxi, and to which company it belongs, and often the status whether the vehicle is available or occupied. To convey this information, the sign is linked into the on-board electronic systems, including the Mobile Data Transceiver (MDT) and meter.

The "For Hire" light needs to be reliable in its function. When the system is operating correctly, when the fare is cleared from the meter, a signal passes to the MDT and the "For Hire" light is automatically activated. It is known that incandescent bulbs fail catastrophically when their wire fails. If the "For Hire" light ceases to work, the vehicle will appear to viewers to be unavailable.

Furthermore, the driver may not be able to access the MDT for work and information. Either of these factors may result in the driver missing out on potential work.

00 a The systems currently employed in illumination of taxi-top lights rely on a base r. to attach the moulded outer cover and to attach the bulbs or fluorescent tubes 0o holders. This form of manufacture is a system for regular failure through excessive vibration that is the main cause for cracks in the moulded cover and IND the stress placed on the bulb or tube assembly. The whole system is reliant on 0screws to hold it together. This physical fragility increases the incidence of

(N

malfunctioning or unsightly signs, either of which is a disadvantage to the driver.

o00 The discussion of prior art in the Background section of the specification above does not constitute an admission that such prior art is widely known or forms part of the common general knowledge in the field.

It would be advantageous if an illuminated sign could be devised that overcomes at least one of the problems with existing signs, or at least provides the public with a useful choice.

Summary of the Invention The present invention provides a sign including at least two sections of optically transparent block, each section including at least one light source associated with a first face of the section and at least one indication associated with a second face of the section, such that when the light source is active, the or each indication is visible.

Preferably at least two of the light sources can be independently activated and deactivated.

In a preferred embodiment, at least two sections of the block are integrally formed.

The indication may be selected from the list comprising: angled boundaries, blocking coatings, transmitting coatings and any combination thereof.

00 O Optionally the indication includes at least one angled boundary, which is Stextured.

0Preferably the block is made from a material selected from the list comprising: glass, polymethyl methacrylate or polycarbonate.

SIn a preferred embodiment at least one light source consists of one or more light emitting diodes (LEDs).

00 The light sources associated with different sections may be selected to provide different frequencies of light.

Preferably a reflective coating is provided on at least part of at least one third face of the block.

The sign may include at least one embedded section of reflective material. In a highly preferred form, the reflective material is reflective acrylic.

In a preferred embodiment, the sign includes at least one obscuring panel, which hides at least one indication when the associated light source is inactive.

In one preferred embodiment, the obscuring panel is a sheet of coloured acrylic.

In an alternative embodiment, the obscuring panel is a polariser.

The present invention further provides the combination of a sign as described above and at least one bracket, wherein the bracket is permanently affixed to a vehicle and the sign can be releasably engaged with the bracket.

Brief Description of Drawings By way of example only, a preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings, in which: 00 00

C

oo oo

IN

00 Figure 1 is a perspective front view of a preferred embodiment of a sign according to the present invention; Figure 2 is a schematic side view of the path of selected rays of light through a primary block of a preferred embodiment of a sign according to the present invention; Figure 3A is a top view of a bracket according to the present invention; Figure 3B is a side view of a bracket according to the present invention; Figure 3C is a cross-sectional view of a bracket according to the present invention; and Figure 4 is a schematic side view of the path of selected rays of light through a secondary block of a preferred embodiment of a sign according to the present invention.

Detailed Description of Preferred Embodiment In a preferred embodiment, shown in Figure 1, the illuminated sign is adapted to be mounted on the top of a taxi.

The sign 1 includes a primary block 2, which is preferably made of Polymethyl methacrylate (acrylic). Acrylic is well-suited to this application because it is transparent to visible light frequencies and can be processed by standard industrial means. Because the block is solid, it has vibrational stability, reducing damage caused by stresses from the vehicle.

An indication 3, such as the word "TAXI" shown in Figure 1, is presented on a face of the primary block 2. Indication 3 may be created by carving symbols into a face of the block to create an angled boundary 4 between the primary block 2 and the indication 3. Angled boundary 4 may be textured to diffuse light incident upon it. Areas on the front face of primary block 2 are coated with an opaque or semi-opaque blocking coating 40 (Figure Other areas may be coated with a transmitting coating 41. The indication 3 may be comprised of any combination of any one or more of: angled boundaries4, blocking coatings 40 and transmitting coatings 41.

00

O

A light source 5 is provided at the bottom of the primary block 2. In this r embodiment, the light source 5 is a strip of light emitting diodes (LEDs). LEDs are more energy efficient than incandescent bulbs, and fail gradually, allowing time to fix any problems before the sign will cease to function properly.

OWhen the light source 5 is activated, light from light source 5 is reflected within the block until it encounters the indication 3. Light impacting on an optical 0boundary 4 is either reflected within the block or refracted so that it passes out of the block (depending on the properties of the boundary and the angle of incidence). Where the optical boundary 4 is textured the light may illuminate the textured surface as it is reflected between and refracted through the peaks and troughs on the surface of the optical boundary 4. When light impacts on the back side of an area of transmitting coating 41, the light can escape the block. No light (or limited light) can escape through the blocking coating 40, so this area remains dark.

In order to increase the amount of light from the light source 5 which is incident on the indication 3, reflective coatings 42 may be applied to at least one face of the block 2. This decreases loss of light from the block 2 through other faces, increasing the amount of light which will be incident on the indication 3.

Thus, the sign 1 provides an illuminated sign which can be seen by a viewer from a distance and/or in the dark. Because the sign 1 is a solid acrylic block, it does not admit water or dirt after the manner of a conventional back-lit sign, leading to an enhanced aesthetic appeal. It is also less vulnerable to the vibrational damage caused by being mounted on a vehicle. The sign also uses LEDs, which are advantageous in providing a range of colour options, higher efficiency and gradual failure.

In an alternative embodiment (not shown), a second indication may be carved into the back side of the primary block. In this embodiment, it is desirable that 00 O the side of any blocking coatings adjacent the block be optically reflective, to

(N

increase the amount of light incident on the other indications.

0The light source 5 may include multiple component light sources of differing output frequencies. For example, an array of different coloured LEDs may be IND provided. The light source 5 may be electronically controlled to emit different Scolours at different times, or to different parts of the sign 1 to create a desired visual effect. In order to enhance this effect, different areas of tuned front 0coating 41 can be used.

The sign 1 can also include one or more secondary blocks 22, which are preferably integrally formed with primary block 2. Embedded in secondary block 22 is a piece of reflective acrylic 44. Adjacent the reflective acrylic 44, a secondary indication 23 is carved into the secondary block 22 to create a textured optical boundary bounding a cavity 45, which is bounded on its other side by the reflective acrylic 44. Secondary block 22 further includes a secondary light source 25; each secondary light source 25 may be of a different output frequency to the primary light source 5, to create a multi-coloured effect.

A secondary obscuring layer 26 prevents a viewer from seeing the secondary indication 23 when secondary light source 25 is switched off. However, as shown in Figure 4, when secondary light source 25 is switched on, light encounters the optical boundary between the secondary block 22 and cavity and further light is reflected from reflective acrylic 44 through the cavity 45. The reflected and direct light illuminate the optical boundary; this effect is enhanced by the texturing of the optical boundary. Obscuring layer 26 is optically transparent or semi-transparent to the frequency of light provided by the secondary light source 25, so that the illuminated optical boundary can be seen by a viewer through obscuring layer 26.

The secondary indication 23 may be a message or symbol relating to the status of the taxi e.g. "For Hire". The obscuring layer 26 is preferably a layer of coloured acrylic which may be adhered to the face of secondary block 22, but 00 may alternatively be a polariser, such as an electronically activated thin film e coating or liquid crystal cell on the front face of secondary block 22.

00 0 It will be appreciated that the reverse side of reflective acrylic 44 may carry a message, which may be a printed message illuminated by a light source within IDthe secondary block 22. Alternatively, a further secondary indication may be 0 carved into the boundary of the secondary block 22 with the back of the reflective acrylic 44.

00 oO The sign 1 may, as shown in Figure 1, include a base section 46 housing the light source 5, and connected via cables 47a to a power supply (preferably solar panels on the roof of the vehicle) and an electronic controller in the vehicle's electrical system. Base section46 includes lugs47 for securing to a bracket 48, shown in Figure 3. Bracket 48 includes a bracket base 49, which is permanently fixed to the top of the vehicle by conventional means. Mounted on bracket base 49 are two upstands 50, spaced apart by the width of the base section 46 of the sign 1. The upstands 50 optionally may be supported by side supports 52. Each upstand 50 includes a kinked slot 51 sufficiently wide to receive one of the lugs 47. A plastic cover (not shown) may be placed over the side sections of bracket base 49 and side supports 52 to enhance the aesthetic appearance of the bracket.

In order to secure the sign 1 to the vehicle, the lugs 47 are lowered into slots 51 and moved into the horizontal section 51a of slot 51. In this position, the lugs 47 cannot move vertically, so sign 1 is held on to the top of the vehicle.

Cable 47a is plugged into the on board electronic system and the sign can be used.

An advantage of the present invention is that the sign can be easily removed from the vehicle by unplugging cable 47a, and manually sliding the lugs 47 out of slots 51. This allows the same vehicle to be either with or without the sign 1, as may be desired.

00 8 0 0 variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth.

00

Claims (17)

1. A sign including at least two sections of optically transparent block, each 0section including at least one light source associated with a first face of the section and at least one indication associated with a second face of O the section, such that when the light source is active, the or each indication is visible.

2. A sign according to claim 1, wherein at least two of the light sources can be independently activated and deactivated.

3. A sign according to either one of the preceding claims, wherein at least two sections of the block are integrally formed.

4. A sign according to any one of the preceding claims, wherein the indication is selected from the list comprising: angled boundaries, blocking coatings, transmitting coatings and any combination thereof.

A sign according to claim 4, wherein the indication includes at least one angled boundary, which is textured.

6. A sign according to any one of the preceding claims, wherein the block is made from a material selected from the list comprising: glass, polymethyl methacrylate or polycarbonate.

7. A sign according to any one of the preceding claims, wherein at least one light source consists of one or more light emitting diodes.

8. A sign according to any one of the preceding claims, wherein the light sources associated with different sections are selected to provide different frequencies of light. 00 O

9. A sign according to any one of the preceding claims, wherein a reflective e coating is provided on at least part of at least one third face of the block. oo00

10. A sign according to any one of the preceding claims, wherein the sign includes at least one embedded section of reflective material.

11. A sign according to claim 10, wherein the reflective material is reflective acrylic. 00

12. A sign according to any one of the preceding claims, wherein the sign includes at least one obscuring panel, which hides at least one indication when the associated light source is inactive.

13. A sign according to claim 12, wherein the obscuring panel is a sheet of coloured acrylic.

14. A sign according to claim 12, wherein the obscuring panel is a polariser.

The combination of a sign according to any one of the preceding claims and at least one bracket, wherein the bracket is permanently affixed to a vehicle and the sign can be releasably engaged with the bracket.

16. A sign substantially as hereinbefore described in the detailed description of the preferred embodiment with reference to Figures 1, 2 and 4 of the accompanying drawings.

17. A combination of a sign and a bracket, substantially as hereinbefore described in the detailed description of the preferred embodiment with reference to Figures 1, 2 and 4 of the accompanying drawings.