DE202006017445U1 - Light module for rear-illuminated lettering, comprises light-conducting plate with two surfaces facing each other, connecting lateral surface and source of light, light or air chambers form recesses in region of spaced adhesive frames - Google Patents

Abstract

The module (1) comprises a light-conducting plate with two surfaces facing each other, a connecting lateral surface (13,16) and a source of light (21,22). The light or air chambers form recesses in the region of spaced adhesive frames, between which at least one diffuser film is arranged, so that this film possesses a distance to the light conductor place and to lower side of the script nameplate. The total structure is brought into the recess of a grouting frame (23) and is filled with a grouting compound.

Description

object The innovation is a light module, especially for a backlit lettering according to the preamble of claim 1.

such Light modules have become known from a variety of documents. For example, from WO 97/40486 a light module has become known, which consists of a luminous symbol plate, the basic carrier a Light guide plate receives, in front of the distance with a front panel with corresponding luminous symbols is arranged. The light sources are here as fluorescent tubes formed, which radiate laterally into the light guide plate. Disadvantage of said arrangement, however, is that the entire arrangement not liquid and is moisture-proof and that there is a risk that both the fluorescent lamps, their power supply as well as the recesses can soil in the light guide plate. Such an arrangement is not for the spray water area suitable.

The US 3,491,245 shows a sheet-metal housing, in the interior of which a light guide plate is arranged, which is irradiated laterally by incandescent lamps.

A such arrangement is also not encapsulated moisture-proof.

With the DE 699 14 089 D2 a luminous display panel has become known in which an image is arranged separately in front of the light guide via an air gap. Such an arrangement is also not liquid-tight and can not withstand high mechanical stresses.

With the DE 196 06 179 A1 is a lighting device made known from a hollow body, in the interior of which a corresponding light source is arranged.

Because of the training as a hollow body there is a risk of moisture precipitation, and there are Sealing problems.

The same criticism applies to the EP 1 489 582 A2 , where a stacked structure of a flare symbol with associated spacers and connectors between the individual stacked layers is shown.

The DE 32 23 706 A1 describes a film viewer with a light guide plate, the surface of which nubs are arranged for light diffusion. There is a cavity between the light-emitting side of the light guide plate and the associated luminous surface, at the back of a diffuser film is arranged. Such an arrangement is also not sealed liquid-tight and can not withstand high mechanical loads.

In the US 6,425,673 a light guide plate and a housing for a light guide plate is shown, wherein the said parts are merely superimposed and mechanically connected to each other, without provisions being made against ingress of moisture.

The same criticism applies to the US 5,584,556 merely schematically illustrates a structure and integration of a light guide in a light housing. The same criticism applies to US 2005/0072032 A1, which shows only an image viewer with a luminous field, which, however, has not cope with high mechanical loads.

Another Disadvantage of the known backlight module is the lack of moisture resistance, because the LED used for lighting is exposed to moisture, as well as all other parts of the backlight, in particular the surfaces between the surface the plastic plate and the diffuser foil placed thereon.

penetrates there water, it comes to condensation phenomena, and the Light impression is greatly attenuated. Incidentally, there are signs of decomposition, which even leads to organic decay phenomena.

• 1. Die Klebefläche an der Oberfläche der Kunststoffplatte und der Unterseite der Diffusorfolie schwächt den Leuchteindruck ab.
• 2. Die unmittelbare Berührung der Diffusorfolie über die Klebeschicht mit der Oberfläche der Kunststoffplatte hat einen weiteren Nachteil, dass eine günstige Ausbreitung der an der Oberfläche der Kunststoffplatte sich ausbreitenden Strahlung nicht gewährleistet ist. Es erfolgt daraus eine schlechte Leuchtdichteverteilung.

Incidentally, the luminance of the known backlight module is severely limited because it is only known to stick the diffuser film directly onto the surface of the plastic plate, which has various disadvantages:

• 1. The adhesive surface on the surface of the plastic plate and the bottom of the diffuser film attenuates the light impression.
• 2. The direct contact of the diffuser film on the adhesive layer with the surface of the plastic plate has a further disadvantage that a favorable spread of the propagating on the surface of the plastic plate radiation is not guaranteed. It results from a poor luminance distribution.

Of the Innovation is therefore the object of a light module, in particular for a backlit Lettering of the type mentioned in such a way that at significantly better light efficiency absolutely reliable sealing against moisture and environmental influences guaranteed is.

To solve the task is the innovation by the technical teaching of Anspru Ches 1 marked.

essential Feature of the innovation is that at least the luminous symbol plate as a basic carrier the light guide plate receives and is potted with this and that in the space between the light-emitting interface of the Light guide plate and the light-receiving side of the light symbol plate an air chamber is arranged, the hermetically sealing closed is.

Important is that the exploded structure in the assembled state Completely is cast, bringing the entire recess in the potting with filled a potting compound is.

On In this way, the light module is absolutely safe against penetration protected from moisture and dust. Furthermore results in a high mechanical stability.

A advantageous embodiment of the invention is that of the plastic plate trained light guide sunken at least on one side to the surface Having depressions, which form a grid surface, which grid surface as Gradient grid is formed, which starting each of the End faces (short narrow sides) in the direction of the central transverse axis a greater grid density occupies.

With The given technical teaching thus results in the essential Advantage that now according to the invention at both opposite End sides of the plastic plate each arranged a light source and that the two light sources are aligned with respect to each other End faces of the plastic plate lie and that of the two Light sources generated light in the volume of the plastic plate spreads and evenly through the history grid described above the surface the plastic plate is formed.

in this connection is essential that the grid by depressions in the surface of the Plastic plate is achieved, wherein at the outer edge regions a smaller grid area is achieved in that in the outer edge regions such conical (conical or frustoconical) depressions only one Depth of z. B. 0.0125 mm, while in the direction of the Center transverse axis occupy an increasing depth and in the area of Center transverse axis then have a depth of 0.25 mm.

Thereby thus arise different sized diameter of the recesses, because the cone bores (eg those with an angle of 90 degrees be introduced) different depth in the plastic plate and thereby have a larger one according to the depth smaller recess formed in the surface of the plastic plate.

In order to results in a significant advantage over the prior art, because such Konusbohrungen can very easy to be produced by injection molding, if the Plastic plate itself is produced by injection molding.

It enough then, in the injection mold such projecting taper pins to bring in, which have different lengths, so they So in the middle transverse axis of the plastic plate a greater depth with accordingly larger sized ones Recesses produce as comparatively in the peripheral areas of Plastic plate towards the illuminated faces of this Plastic plate.

This is a significant advantage over the prior art, because in the prior art, it was only known grid points Apply by printing on the surface of a plastic plate. However, such pressure points are a certain mechanical abrasion already subjected to assembly, they have no great long-term stability and they form effective obstacles for the irradiated surface the plastic plate, d. H. they only leave the radiation very bad by. It is therefore not the entire surface of the plastic plate as Radiation source exploited what in the present invention done in a completely different way.

at According to the present invention, the core is that through the Incorporation of cone recesses no radiation-weakening Districts in the plastic surface be achieved, but rather radiation-enhancing districts, because through the cone depressions in this case further angular ranges in the area the surface The plastic plate is created for a reflection of this angled surfaces impinging light rays provide.

In order to becomes the radiation quality and the radiation density at the surface of this plastic plate significantly improved. It has better long-term stability because print dots printed in the printing process do not decompose, mix or otherwise mitigate. You can not - which at Printing inks are very common the contained solvent the plastic surface hurt or weaken.

Incidentally, register problems also arise during printing, ie there is a risk that the surface will not be printed in register, which is associated with a further loss of quality. Such problems arise during the introduction of cone holes in the surface of a plastic plate not.

In a preferred first embodiment, it is provided that such Recesses arranged only in the bottom of the plastic plate are, i. on the far side, the backlit lettering away.

In However, it can also be provided for a further embodiment of the invention be that in addition to the bottom, the top of the plastic plate with such rastered countersinks is provided, this surface next to the backlit lettering is located, and in a third embodiment It may be provided that only the top with such grid recesses is provided while the underside is smooth and flat.

to further improvement of the radiation quality, in particular the radiation density It is provided in a development of the invention that so-called Light chambers or air chambers in the space between the surface of Plastic plate and the underside of the backlit lettering are arranged.

such Light or air chambers are defined by recesses in the range of Adhesive frame achieved, with two adhesive frame at a distance above each other are arranged and between the adhesive frame in this case a diffuser film is arranged.

Thereby gets these arranged in the middle region between two adhesive frame Diffuser film both a distance to the luminous surface of the Plastic plate as well as a distance to the backlit Bottom of the lettering.

By the arrangement of these recesses are in the range of adhesive frame according to the before mentioned Light or air chambers formed for improved propagation allow this light or air chambers penetrating radiation.

It hereby comes to a further diffuser effect and to another Improvement of light distribution both at the bottom of the diffuser film as also at the top of the diffuser film towards the bottom of the backlit lettering.

In the case, that in relation to the aforementioned embodiment, the cone-like Depressions only on the underside of the plastic plate, d. H. are arranged away from the backlit lettering, it is further preferred if directly on this bottom one Adhesive layer is applied and applied to this translucent adhesive layer a translucent Diffuser film is glued on, which at its underside by a not translucent Covering foil is covered.

The in the way of the reflection at the bottom of the plastic plate in Area of conical countersinks emerging light rays thus reach the volume of the diffuser film and become on the surface the cover sheet reflected, which in turn created there reflected light rays in the volume of the plastic plate feeds back.

It It goes without saying that the cover sheet with an associated Adhesive layer is glued to the underside of the diffuser film.

By these measures there is a significant increase the luminance and an improvement of the luminance distribution.

It It goes without saying that all adhesive layers used here are made absolutely transparent and / or translucent to the Not obstruct light passage.

One Another feature of the innovation is that a relief-like lettering is backlit. This means that on a transilluminable Relief plate raised symbols are arranged by assigned Recesses - which just release the icons - one opaque Reach through the front panel.

in this connection Does it then come to the desired lighting effect, leaving only the sublime symbols in the assigned cutouts the front panel are lit while all others, remaining parts the enlightened relief plate are not visible from the outside.

The However, the invention is not limited to this embodiment of the backlight a relief plate with material integrally molded thereon symbols limited.

In In another embodiment, it may be provided that the relief plate is formed as a straight plate, in the example, letters, symbols and the like milled are.

In a further embodiment Overall, such a plastic plate can be illuminated, wherein then the corresponding symbols, documents and the like in the printing process are applied.

In the simplest case, however, the relief plate can be shaped as a flat or three-dimensionally deformed Plastic plate are formed, which is suitable as a luminous surface for the backlighting of different objects. Such articles are trim or decorative elements used in the automotive or consumer sector (eg, kitchens or living areas or home appliances with LCD backlighting).

As well Is it possible, that the relief plate or the - in a training so trained - level plastic plate different, different colored plastics is formed, to achieve differently colored light impressions in the area of the visible surface.

Under the term "screen density" in claim 1 is Here, the degree of surface removal of a planar light guide surface Understood. This degree of erosion can be achieved by various measures be achieved, namely e.g. by attaching various large holes or by arrangement same holes in the changing distance.

Under The term "hole" here are tapered blind holes Understood.

In the preferred embodiment, the blind holes have the same distance, but different diameter, by the penetration depth of a Cone tip in the surface is conditional.

In In a further embodiment, it is preferred if the conical surface of the conical blind holes rough (not polished and not smooth) are formed there to the Light scattering effect to improve.

In a further embodiment is preferred when the light guide plate is not formed as a flat plate, but as a three-dimensional Body. In this case, the grid density is the curvature of the three-dimensional body customized. A three-dimensional deformation is necessary in some cases around a likewise three-dimensional object (for example a front panel and an associated one Relief plate) to backlight.

Of the Subject of the present innovation does not arise only from the subject of the individual claims, but also from the combination the individual protection claims among themselves.

All in the documents, including Summary of information and features, in particular the spatial training shown in the drawings as claimed essential to the invention, as far as they individually or in Combination opposite the prior art are new.

in the The following is the innovation of only one execution way illustrative drawings closer explained. Here are more from the drawings and their description essential features and benefits of the innovation.

It demonstrate:

1 : Perspective view of the luminous element with a front panel remote therefrom

2 : the layer structure of the luminous element after 1

3 : A schematic section through a luminous element in the assembled state

4 : Perspective view of a flex conductor with light sources

5 : a detail of the representation after 4

6 : The top view of a plastic plate in training as a diffuser

7 : Cut through the arrangement after 6

8th : an enlarged view of the section after 7

9 : the top view of the underside of the plastic plate with the gradient grid

10 : schematized and greatly enlarged a section through the light module after the innovation

The light module 1 The new feature is used to backlight a front panel 2 in which a symbol contour 3 punched out and the backlit to be.

For this purpose, the light module 1 at the top an adhesive layer 4 on, directly to the bottom of the front panel 2 is glued, wherein the adhesive layer is recessed according to the desired contour to be illuminated.

Through the recesses in the adhesive layer 4 picks up a relief plate 5 through, the material integrally raised symbols 6 wearing, which accordingly through the recesses in the adhesive layer 4 reach through and the symbol contour 3 in the front panel 2 fill out. The light module should according to the raised symbols 6 , which by the symbol contour 3 in the front panel 2 reach through, with high and uniform luminance illuminate th.

For this purpose is at the bottom of the relief plate 5 a first adhesive frame 7 arranged, in its center region a recess 8th has, in its dimension about the backlit surface of the symbol contour 3 equivalent.

At the bottom of the adhesive frame 1 is a diffuser film 9 adhered, which consists for example of a transparent paper.

At the bottom of the first diffuser film 9 puts a second adhesive frame 10 at the same recess 11 that has the recess 8th in the first adhesive frame 7 in alignment.

This will be a distance of the diffuser film 9 both opposite the bottom of the relief plate 5 as well as towards the luminous top of the plastic plate 12 reached.

The light-generating element after the innovation consists of a plastic plate 12 , which consists of a conventional, transparent plastic, wherein an elongated, rod-shaped element is formed.

However, the invention is not limited to the particular shape of this plastic plate 12 limited. Any desired shapes of the plastic plate can be used. In the illustrated embodiment, the plastic plate has dimensions of z. B. 100 mm × 30 mm and a thickness of 2 mm.

The long narrow sides 13 . 13a the plastic plate 12 are mirrored. For this purpose, mirror films can be applied or applied by printing, so that essentially at the circumferential long narrow sides 13 . 13a the plastic plate 12 Verspiegelungen 14 are located.

It is also important that the end portions of the plastic plate taper approximately conically and evenly and in narrower open end faces 16 lead to the light sources required for lighting 21 . 22 lie positively. It is important that these narrower, tapered areas of the plastic plate 12 also mirrored surfaces 15 form.

Regarding the exact structure of the plastic plate 12 is determined by the 7 to 9 even more received.

At the bottom of the plastic plate 12 puts a transparent light guide adhesive as an adhesive layer 17 on whose underside turn a second diffuser film 18 is attached.

At the bottom of the diffuser film 18 is a cover foil 19 arranged, on its underside an adhesive layer 27 carries, with the help of a flex conductor 20 stuck there.

The exact structure of the flex conductor 20 is determined by the 4 and 5 described in more detail.

Incidentally, the cover film carries an adhesive layer on its upper side, so that it attaches to the underside of the diffuser film 18 can be glued.

The entire structure is in a circumferential Vergussrahmen 23 introduced and fills the recess 24 out.

The top of the potting frame 23 Carries an adhesive layer, allowing the potting frame directly to the underside of the front panel 2 is glued on.

Importantly, the in 2 exploded structure is completely potted in the assembled state, bringing the entire recess 24 in the potting frame 23 filled with a potting compound.

In this way, the light module 1 absolutely safe against ingress of moisture and dust. In addition, there is a high mechanical stability.

The 1 still shows that the two light sources 21 . 22 , which are preferably formed as LED, with the aid of an adhesive layer 28 (Superglue) to the front 16 the plastic plate 12 are glued.

The front of the cover 19 Carries an adhesive layer, which attaches to the underside of the diffuser film 18 is glued on.

The 3 shows the more detailed structure of the arrangement, where the above-mentioned parts are shown in sectional view in the assembled state.

There it can be seen that the peripheral edge of the potting frame 23 an adhesive layer 25 carries, with this to the underside of a front panel, not shown there 2 is glued on.

The 4 and 5 show the structure of the flex conductor. Here it can be seen that the flex conductor 20 with the help of an adhesive layer 27 on the cover 19 is fixed and also two opposing and oppositely directed angle pieces 26 that is out of the plane of the flex conductor 20 hey bent out.

In the area of these contra-angles 26 become the two light sources 21 . 22 attached so that they are directed against each other and aligned with each other.

Alternatively, the flex conductor 20 also be straight, and the corresponding light sources 21 . 22 are then executed angled.

The 5 shows that on the flex conductor 20 one or more SND resistors 29 can be arranged.

The flexible conductor can also be made from the potting compound of the potting frame 23 protrude to the electrical connection of the entire light module 1 to ensure.

The 6 to 9 show the exact structure of the plastic plate 12 with one at the bottom 30 existing grid area 33 ,

The 6 shows first that the long narrow sides (edges 13 . 13a ) Reflections 14 Wear, extending to the area of the front and rear open ends 16 extend.

Likewise, the tapered surfaces of the plastic plate on the top and bottom with mirrored surfaces 15 Mistake.

If lower luminance levels are desired, the above-mentioned reflective coatings can 14 . 15 also be omitted.

The 7 to 9 now show a special training a grid area 33 on the bottom 30 the plastic plate 12 ,

It can be seen that from the lateral end faces 16 starting in increments of z. B. 0.0125 mm cone holes in the form of the wells 32 are arranged. Here, two rows are always the same, ie the wells arranged there 32 have the same diameter in that they have the same depth of z. B. 0.0375 mm.

Toward the center area 34 However, the depth of the holes increases, their distance remains the same, and this results in a gradient grid. In the middle area, these holes have a depth of 0.25 mm, for example.

This results in a gradient grid whose density in the region of the end faces 16 is low and its density is continuously on the central longitudinal area (center area 34 ) increases.

Thus, the luminance distribution over the volume of the plastic plate 12 optimized.

Incidentally, in this embodiment, it is shown that the upper side 31 is completely smooth and scratch-free. It is preferably polished. The angle 35 between the straight front ends 16 and the adjoining long narrow sides of the plastic plate is preferably 130 degrees.

The 9 clearly shows a density gradient 36 of the grid so that the grid density of the end faces 16 towards the center area 34 continuously increases.

The resulting benefits are in 10 schematized and shown in exaggerated proportions. By at the bottom 30 arranged differently grooved recesses 32 This results in a favorable reflection of the light sources 21 . 22 in the direction of the arrow 37 irradiated light rays, which are therefore in the entire volume of the plastic plate 12 to distribute. Such light rays also strike in the direction of the arrow 38 on the conical recesses, are reflected there and, for example, in the arrow direction 39 emitted in all directions.

They are therefore also from the bottom of the plastic plate 12 out through the adhesive layer arranged there 17 in the arranged there diffuser film 18 irradiated, enforce this diffuser film 18 and become on the surface of the cover 19 reflected. This is in the form of arrow directions 40 . 41 shown, so that there from the bottom back into the volume of the plastic plate 12 incoming light rays repeatedly at the cone-shaped recesses 32 be reflected and again in the volume of the plastic plate 12 be scattered.

This results in a favorable diffuser effect in the interior of the plastic plate 12 , and the diffused light beams thus generated become, for example, in the arrow direction 42 in a first recess 11 (Called air or light chamber) of the adhesive frame 10 passed through and then get to the distance from the surface 31 the plastic plate 12 held diffuser film 9 into it.

This results in a widespread diffuser radiation in the diffuser film 9 , and those from this diffuser film 9 in the direction of the arrow 43 emerging light rays in turn pass through the spacer recess 8th of the adhesive frame 7 to the underside of the relief plate 5 , which is backlit thereby with the largest possible diffuser light radiation.

The material of the relief plate 5 is transparent and / or translucent and can be colored in any way. The relief plate can also be designed in several parts. The light rays entering there thus occur in the direction of the arrow 45 through the sublime symbols 6 through which by the punched out symbol contour 3 the front panel 2 reach through.

The 10 shows, moreover, that in the area of the raised symbols still opaque imprints can be attached, as with the contour print 44 is shown. In this case, only the outer areas outside the contour heading 44 the sublime symbols 6 be enlightened.

For connecting the light module 1 with the front panel 2 It can also be provided, moreover, to connect the two parts directly in an injection molding process. For this purpose, it is then provided that the light module is inserted into the injection mold together with the front panel and that by the symbol contour 3 the front panel 2 a back-lit plastic is sprayed through it, which in the cured state, the relief plate 5 with the sublime symbols 6 results. This would then also the Vergussrahmen 23 of the light module with the back of the front panel 2 connected.

1

light module

2

front panel

3

negative Symbol contour (punched out)

4

adhesive layer

5

relief plate

6

positive sublime symbols

7

adhesive frame 1

8th

recess

9

diffuser film 1

10

adhesive frame 2

11

recess

12

Light guide plate (Plastic)

13

Long narrow side; 13a sloping narrow side

14

Mirroring of 13 . 13a . 15

15

Surface (mirrored)

16

short Narrow side (optically open front side)

17

adhesive layer

18

Diffuser foil 2

19

cover

20

Flex Head

21

light source (LED)

22

light source (LED)

23

Vergussrahmen

24

recess

25

adhesive layer

26

elbow

27

adhesive layer

28

adhesive layer

29

SMD resistor

30

bottom (Rasterized)

31

top

32

deepening

33

grid area

34

mid-range

35

angle

36

density curve

37

light rays

38

arrow

39

arrow

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arrow

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arrow

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arrow

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Contours publication

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Claims (19)

Light module ( 1 ), in particular for a backlit lettering ( 3 . 6 ), including a light guide plate ( 12 ) with two opposing surfaces ( 30 . 31 ) and at least one lateral surface ( 13 . 16 ), and including at least one light source ( 21 . 22 ), whose light over at least a part of the lateral surface ( 13 . 16 ) in the light guide plate ( 12 ) is introduced, and from this again over at least one of the surfaces ( 30 . 31 ) diffusely scattering, wherein the at least one diffusely scattering surface ( 30 . 31 ) of the light guide plate ( 12 ) recessed depressions ( 32 ) having a light-scattering screen surface ( 33 ), characterized in that the light or air chambers ( 8th . 11 ) Recesses in the area of spaced-apart adhesive frame ( 7 . 10 ) between which at least one diffuser film ( 9 ) is arranged so that they both a distance from the light guide plate ( 12 ) as well as the underside of the lettering ( 3 . 6 ) owns and that the entire structure in the recess ( 24 ) of a potting frame ( 23 ) is introduced and filled with a potting compound. Light module according to claim 1, characterized in that for the connection of the light module ( 1 ) with the front panel ( 2 ) The two parts are connected directly in an injection molding process. Light module according to claim 2, characterized in that the light module ( 1 ) in the injection mold together with the front panel ( 2 ) is inserted and that by the symbol contour ( 3 ) of the front panel ( 2 ) through a back-lit plastic is sprayed, in the cured state, the relief plate ( 5 ) with the raised symbols ( 6 ). Light module according to claim 2 or 3, characterized characterized in that the potting frame ( 23 ) of the light module with the back of the front panel ( 2 ) is connected by injection molding. Light module according to one of claims 1 to 4, characterized that the grid density such a distribution on the surface of Fiber optic plate forms that the lighter areas a greater grid density and the darker areas are assigned a low. Light module according to one of claims 1 to 5, characterized that the light guide plate is deformed three-dimensionally. Light module according to one of claims 1 to 6, characterized in that the at least one light source ( 21 . 22 ) is an LED. Light module according to claim 6 or 7, characterized in that the respective light source ( 21 . 22 ) associated with depressions ( 32 ) a grid area ( 33 ) whose raster density depends on the short sides ( 16 ) starting in the direction of the central transverse axis ( 34 ) of the rectangular light guide plate ( 12 ) increases. Light module according to one of claims 1 to 8, characterized in that on two short end faces ( 16 ) of the light guide plate ( 12 ) one LED each ( 21 . 22 ) which are opposed to each other. Light module according to one of claims 1 to 9, characterized in that between the right angle (short) ( 16 ) and long narrow sides ( 13 ) at an angle of 45 ° extending oblique narrow sides ( 13a ) and thus at the ends of the plane surfaces ( 30 . 31 ) triangular surfaces ( 15 ) are formed. Light module according to claim 10, characterized in that the long narrow sides ( 13 ) and / or the oblique narrow sides ( 13a ) and / or - with the exception of the short narrow sides ( 16 ) - the surfaces of the triangular surfaces ( 15 ), a totally reflecting mirroring ( 14 ) exhibit. Light module according to one of claims 1 to 11, characterized in that the recessed depressions ( 32 ) are cone-shaped and the peripheral recesses ( 32 ) a small depth of z. B. 0.0125 mm, which in the direction of a central transverse axis ( 34 ) of the light guide plate ( 12 ) increases to a depth of z. B. 0.25 mm. Light module ( 1 ) according to claim 12, characterized in that the cone of the recessed depressions ( 32 ) has a cone angle of 90 °. Light module ( 1 ) according to claim 12 or 13, characterized in that the recessed depressions ( 32 ) by injection molding in the light guide plate ( 12 ) are introduced. Light module ( 1 ) according to one of claims 1 to 14, characterized in that light or air chambers ( 8th . 11 ) in the space between at least one of the surfaces ( 30 . 31 ) of the light guide plate ( 12 ) and the underside of the backlit lettering ( 3 . 6 ) are arranged. Light module ( 1 ) according to one of claims 1 to 15, characterized in that on the one with the recesses ( 32 ) ( 30 . 31 ) of the light guide plate ( 12 ) a translucent adhesive layer ( 17 ) is applied, on which a translucent diffuser film ( 18 ) is adhered to which a non-translucent cover ( 19 ) is applied. Light module ( 1 ) according to one of claims 1 to 16, characterized in that on a transilluminable relief plate ( 5 ) sublime symbols ( 6 ) of the lettering of the front panel ( 2 ) arranged by associated recesses ( 3 ) of the lettering of an opaque front panel ( 2 ), which only the symbols ( 6 ) leave with or without some play. Light module ( 1 ) according to one of claims 1 to 17, characterized in that the lettering in a newly formed relief plate ( 5 ) is materialized by material processing such as deformation, casting, stamping, milling, laser and / or there is attached as a separately manufactured element, for example, printed and / or glued. Light module according to one of claims 1 to 18, characterized in that the peripheral edge of the Vergussrahmens ( 23 ) an adhesive layer ( 25 ), with which this to the underside of the front panel ( 2 ) is glued.