FI104652B - Light diffuser for billboards and billboards - Google Patents

Description

1 104652

Light diffuser for billboards and billboards

The invention relates to a light diffuser and light panels using a light diffuser. Specifically, the invention relates to lightboards used on billboards, billboards, and backlighting of LCD panels.

Such panels are usually made in the form of a light cabinet, which, depending on the size of the panel, is provided with one or more fluorescent tubes for backlighting the panel. The pictures or information are placed on a transparent cover or plate which is illuminated with light coming from the cabinet fluorescent lamp (s). In order to distribute the light as best as possible and as evenly as possible over the whole surface to be illuminated, a hi-15 diffuser and a diffuser respectively are located behind the fluorescent lamp or tubes. In addition, the lid must be frosted. The disadvantage of these already known light board structures is that the box structure becomes relatively deep or of high structural height so that light is distributed satisfactorily throughout the surface.

20 U.S. Patent 4,791,540 discloses a lightboard. It is made into a box in which the light source can be placed either under the cover plate or at one or more of the lateral edges. The cover plate comprises a plastic foil which is smooth on one side and has longitudinal grooves on the other side (the so-called SOLF film manufactured by 3M). *: · *: The base plate is provided with a reflective or mirrored surface or · * · *: Made of SOLF film on a matte surface. When the light source is positioned at one of its side edges, the SCLF foil is placed between the fluorescent lamp and the light box.

30 In order to achieve a satisfactory light distribution, these well-known illuminated panels of * * · · height. is small, special power devices have been used, for example «fr light-conducting plates or films that direct light.

It is an object of the present invention to provide a structure specifically designed for light boards of the type mentioned in the beginning 2,104,652 and having a minimum height of structure with the light being evenly distributed over the largest possible surface.

This object is achieved by means of a light panel using a light diffuser, the features of which are apparent from the claims.

When using the claimed light diffuser, the light panels can be made 50 to 60 mm strong when illuminated on one side, and 70 to 90 mm strong, illuminated on both sides. This strength is necessary due to the diameter of the fluorescent tubes. In this case, the image or information displayed on the light board will have a uniform luminous intensity, a high luminous power, and a low power consumption.

Another advantage of a light panel with a diffuser is that its entire surface is illuminated. The light board has no frame edges and no light source at the side that can be obscured.

The invention will be explained in more detail with reference to the construction examples set forth in the following drawings.

Figure 1 is a vertical sectional view of a illuminated illuminated table with information on one side and a light source.

Figure 2 shows the light panel of Figure 1 as viewed from above with the cover plate removed.

Fig. 3 is a vertical sectional view of a illuminated illuminator with information on one side and two illuminators.

... Figure 4 shows the light table according to Figure 3 above. when viewed with the cover plate removed.

Fig. 5 is a vertical sectional view of a illuminated table with information on both sides.

Figure 6 is a top view of the light panel of Figure 5 with the cover plate removed.

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Figure 7 shows a structure of a light diffuser.

Figure 8 shows the passage of light through the light diffuser shown in Figure 7 as a function of the centerline distances.

The figures illustrate examples of the structure of a lightboard according to the invention, illustrating only the principles of the invention.

The illuminated panel according to the invention can be used as modules and the modules can be joined together in both width and longitudinal direction, so that the illuminated panel is in each case corresponding to the desired dimensioning.

In Figure 1, the base plate is denoted by reference numeral 1 and the side walls by reference numerals 13 and 14.

15 The retro-reflector, comprising a straight surface and a curved surface, is designated by reference numeral 2.

The reflector 2 is a plate having an uneven, rough surface so that it reflects light in all directions, so that it has no dominant light reflection direction. The Hi-20 Strainer 2 is preferably an aluminum plate of type designation ANO-FOL, DSS-10 / R, STUCCO and supplied by Metalloxyd CmbH, Cologne, Germany.

ί Reflector 2 has a white coat • of white paint, preferably containing pigments with: '25 reflection loss as low as possible.

···: In its simplest form, the reflector 2 may be a white plate, for example, a white painted metal • ·. •: \ plate. This type of board provides a lighter • • · luminous density to the entire deck than current lightboard technology.

... 30 The reflector 2 has one straight part of the light source 3 • «· · · ·,. below and two curved sections. Reflector 2 is symmetrical • · t '· * * on both sides of centerline. The straight portion is 20 - 40% / of the width of the light board, preferably 30%. The curved parts have a radius of curvature of 250 to 350 mm, preferably 300 mm.

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The width of the illuminated panel depends on the compromise solution for the requirement of uniform illumination and luminance of the surface. If the width of the illuminating panel needs to be adjusted, the width of the 5 straight sections beneath the light source of the reflector is preferably kept constant, but instead the radius of curvature of the curved sections is increased or decreased.

Light source 3 is generally a fluorescent lamp. The light source may also be two fluorescent tubes, or a plurality of fluorescent tubes 10 placed one above the other or side by side, or the light source may be a compact fluorescent tube, which may vary in construction.

A light diffuser 4 is disposed above the light source 3 in parallel with the cover plate 5. The light scattering tin 4 is a plate having an opaque region above the light source. Outside this range, the disc is light-transmitting. The light transmittance increases towards the side edges of the board, but not necessarily in a linear fashion. In addition, the diffuser 4 is partially reflective. A portion of the light source 3 comes in only 20 light reflected from the side of the light diffuser 4 facing the light source 3. The light diffuser and its structure shown in Figures 1-6 will be further described with reference to Figures 7 and 8.

At the top of the illuminated panel is a 25 cover plate designated 5. The cover plate is made of frosted glass or frosted plastic, and is white or milky in color and diffuses light.

· * · '; Pre-switching of fluorescent or compact fluorescent lamps • ·. ·; *. devices or electronic ignition devices may be located below the reflector and shall be designated ... 30 Sat 6.

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Fig. 2 is a top view of the light panel of Fig. 1 with the cover plate 5 removed. Lightbox is: ': a rectangular box whose dimensions depend on: ·! the length of the light source 3. The holders of the light source 3, for example the holders of the fluorescent lamps, are denoted by reference numerals 104652 9. They are affixed to the side walls 11 and 12 of the illuminated panel. The side walls 11, 12, 13 and 14 are white on the side 15; for example, they are painted white.

The side walls 11, 12, i3 and 14 form a frame 5 and can be dimensioned so that the frame becomes strong and self-supporting. The base plate 1 is then not needed at all. The reflector 2 then serves as a base for the illuminated panel. The structure of the lightboard is thus very simple and the manufacturing costs can be kept low.

The illuminated panel shown in Figures 1 and 2 can be used as a module and larger modules can be formed. At the points where the deck plates are connected, overlapping edges are formed, which are usually somewhat visible.

15 For better results, the cover plate 5 is made as a single sheet, which has no seams and covers all the modules included in the illuminated board.

Fig. 3 is a vertical sectional view of a light panel comprising two light sources. The reference numerals of this figure correspond to the parts represented by the reference numerals of FIG. 1.

Figure 4 is a top view of the light panel of Figure 3 with the cover plate removed. Reference numbers:. corresponding to the parts represented by the reference numerals of Figure 2.

Figures 3 and 4 show a further improvement in the formation of the larger light panels 25 by forming overlapping edges ·; ··; then completely missing out. In this case, the illuminated table · * · * has two light sources 3 which are parallel to each other and at a certain distance from each other. This design can also be applied to a lighting panel ... r 30 with at least three light sources which are • * · central. I .. are parallel to one another and at a certain distance to each other.

Multiple light sources can be placed in series in the same frame with their holders secured to the corner brackets 35.

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3 and 4, having at least two light sources 3, is symmetrical on both sides of its center line.

In such a light panel, the curved portion of the reflector at the transition between the light sources is only 5 to 50% of the structural height, preferably 20%, while at the lateral edge the curved portion of the reflector corresponds to the overall height of the panel.

Fig. 5 is a vertical sectional view of a light panel 10 illuminated and comprising information on both sides.

Figure 6 is a top view of the light panel of Figure 5 with the cover plate removed.

The illuminated panel of Figures 5 and 6 comprises side walls 11, 12, 13 and 14 which form a frame. The 15 are mechanically dimensioned so that the light board is strong and self-supporting. The side walls 11 and 12 are provided with brackets 9 for light sources which are fluorescent tubes 3. Fluorescent tubes 3 are disposed on the center line of the light panel.

Light diffusers 4 are disposed on both sides of the fluorescent tubes 3. The light diffusers 4 are parallel to the cover plates 5.

: The covers 5 are made of frosted glass or frosted, white or milky colored and light-scattering.

The cover plates 5 are parallel to each other and are: ·; · 1: spaced at the same distance from the center line of the light board.

• ·. ·· .1. The cover plates 5 reflect part of the light coming from the fluorescent tubes 3 on the ... side 30 facing the interior of the light panel. The combination of light through the diffuser 4 and the reflection from the diffuser 4 and the cover plates 5 · · 1 ensures an effective effect so that the luminous intensity is uniform over the surface of the illuminator.

·; ··· When the fluorescent tubes 3 illuminate both cover plates .1. 35 5, multiple types of light sources must be used in these types of light panels 7 104652 to produce the same light intensity of the cover plate 5.

Figure 7 shows a part of a diffuser structure designated by reference numeral 21. Various diffuser structures are already known, for example as light filters or dimmers for optical instruments.

The light diffuser 21 is made of a light impermeable white plate. It must be in the form of a non-volatile material, for example metal, which may be formed with a white coating of white paint, preferably containing pigments with minimal reflection loss. The advantage of this design is that the light diffuser 21 does not change over time due, for example, to the heat generated by the light source.

The plate has two perforated fields 22 and 23 disposed symmetrically with respect to the centerline. These fields 22, 23 form the light-transmitting regions of the light diffuser 21.

The holes may have different shapes, for example triangles, squares, rectangles or circles, or a combination of these 4f shapes. Perforated surfaces; the size of the holes may also vary.

In Figure 7, the holes 74 are circular. Perforated light ·; ··: The advantage of the diffuser is that the pattern remains constant.

Number of holes per unit area and number of holes

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the diameter forms the light transmittance of the light diffuser.

30 In order to distribute the light as evenly as possible,

A A A

It has been found that the light transmittance of the light diffuser must increase from the center of the plate towards its side edges. However, light transmission does not increase: · linearly adjusts. This can be achieved by changing the perforations, either by increasing the number of holes or their size.

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The perforations in the fields 22, 23 are only one structural example to achieve the desired light transmission.

The light diffuser shown in Fig. 7 has side edges consisting of semicircles, the edges 5 being approximately wavy. Wavy side edges have been found to provide better light distribution than straight side edges. For example, the lateral edges may be made to have fully symmetrical wave structures consisting of sinusoidal or semicircles, or a saw or hammer mass or rectangular structure, or a combination thereof. The distance between the two waveguides may be 3 to 15 mm, preferably 7 mm, and the amplitude may be 1 to 10 mm, preferably 2.5 mm.

Both the width and the length of the diffuser depend on the shape of the light source. The width can be 2-5 times the width of the light source. When the light source is a standard fluorescent tube with a diameter of 26 mm, the width of the diffuser is preferably 80 mm.

Fluorescent tubes usually give less light near the electrodes. Therefore, the length of the light diffuser may be 75-100% of the length of the light source. With current fluorescent lamps, the length of the diffuser is 80 to 95% of the length of the fluorescent lamp, depending on its power and length.

Figure 8 is a graph showing the light transmittance as a function of the distances * * · ': of the center line of the light *: **: diffuser (Figure 7). The light transmittance is defined as the ratio of perforated area · · as a function of total area and expressed as a percentage.

30 The light transmission is represented by a bar graph. As an example, the diffuser of the light · · · is divided into three · · · * starting from the centerline. fields indicated by fields 1, 2 and 3 and the light transmittance v / opacity is shown for the half of the diffuser.

Field 1, which is 10% of the area, is perforated-35, so it has a light transmittance of 0%.

a 9 104652 The light transmittance of field 2, which makes up 32% of the area, is 23, and the light transmittance of field 3, which makes up 58% of the area of the diffuser, is 43%.

The combination of the light transmittance formed by the light diffuser and the reflection from the light diffuser placed on the 5 light sources and the shape of the reflector produce a power effect so that a uniform light density is obtained throughout the light panel. This applies only to illuminated panels on one side.

In addition, high light output is obtained for light panels incorporating a light diffuser because most of the light from the light source is reflected only once and no light-conducting plates or films are used which cause transmission loss.

15 In the case of illuminated panels on both sides, the cover plates function partly as a reflector. In such panels, the combination of the light transmittance of the light diffusers placed on the light sources and the reflection from the light diffusers, as well as the reflection from the cover plates, produces a power effect so that a uniform light density is obtained on both cover sheets.

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Claims (4)

Light diffusers intended for use in light panels, said light diffusers intended to be positioned near a fluorescent lamp 5 and facing a cover plate, the light diffuser being partly reflective on a side facing the light source and provided with areas of different light transmittance characteristics. The light diffuser (4, 21) is formed as a pianous disc body, arranged parallel to the cover plate (5), wherein the width of the light diffuser is 2 - 5 threads, heist 3 threads, the width of the light source (3), and the 1 light diffuser (4, 21). ) is not light transmissible in an area directly in front of the light source (3) and the light transmittance increases in direction away from the light source (3) and the light transmittance of the light diffuser 15 is varied by two perforated areas (22, 23) disposed on its bed side. equally long distance from its center line directly in front of the light source (3) and where the perforation is arranged so that the area of the openings increases where the heel of the al increases or size grows in the direction of leaking from the center line. Light diffusers according to claim 1, characterized in that the 1-diff diffuser (4, 21) is formed of a white non-light-transmitting disc, which has two perfused areas (22, 23), one in each case. side of the center line and 25 at the same distance from it, these areas being • f *: 1 light-permeable areas, and that the perforation, that is, the 1-permeable area is 25 - 45% of the total area, heist 31%, and increases from 23% near the center line to 43% at the lateral edges, and that the non-perforated area at the midline may be up to 30% of the area of the disc *, 10%. 3. Light diffusers according to Claim 1, character- i I <'iif! assuming that the length of the 1-jus diffuser (4, 21) is 75 - 100% of the length of the light source (3) depending on the effect of the light source (3). Light diffusers according to claim 1, characterized in that the heel constituting the perforation in the light diffuser can have any shape heist, heist round, and that the side edges are approximately road-shaped or saw-tooth-shaped or include rectangular recesses or are a combination of these shapes. • · | I • · · · • V • · * • · · · · · · · · · · · · · · - · · · · M · · • · ·