WO2009000567A1

WO2009000567A1 - Apparatus which can be illuminated

Info

Publication number: WO2009000567A1
Application number: PCT/EP2008/053185
Authority: WO
Inventors: Hans Lichtenstein; Damian Machert; Oliver MÜCK
Original assignee: Evonik Röhm Gmbh
Priority date: 2007-06-28
Filing date: 2008-03-18
Publication date: 2008-12-31
Also published as: DE102007030263A1; TW200926088A

Abstract

An apparatus which can be illuminated, containing at least one light source, a lower cover which is associated with the light source, scatters light and is composed of multicoloured (DIN 5033, part 1) plastic which has a transmission (DIN 5036) of at least 35% and a reflection (DIN 5036) of at least 15% at the wavelength of the relative energy maximum of the light source, and an upper cover composed of a plastic which is coloured transparent grey and has a transmission of 5 to 20% at the wavelength of the relative energy maximum of the light source, and its use as advertising or notice board is described.

Description

Illuminable device

The invention relates to an illuminable device and its use as an advertising or information board.

Illuminable devices, eg. As for billboards, consisting essentially of a light source and a light source associated with the light-diffusing cover made of colored plastic, are in principle known (eg., JP 61159440). In general, incandescent or fluorescent tubes are used as light sources, which have a good luminosity and emit a wide spectrum of light. Due to the wide spectrum of light corresponding colored plastic covers appear in unlit condition, ie z. B. in daylight, in the same color impression, which can be perceived even with backlighting by means of said light sources.

Light-emitting diodes (LEDs) are of significantly lower luminance compared to light sources such as incandescent lamps or fluorescent tubes. However, colored LEDs are still very noticeable in the dark, since they emit an almost monochromatic light, which in turn is relatively intense in the respective wavelength range. Corresponding colored LEDs are available from several manufacturers z. B. in the colors red, green, blue and yellow available.

Dyeing and Dyeing process for plastics such. B. polymethyl methacrylate are well known z. From EP-A-130 576.

US 5,355,284 describes a mirror assembly, in particular rearview mirrors for vehicles. The module can contain additional functions, eg as additional brake light, turn signal and / or clock. For this purpose, a dichroic mirror is used, which reflects the visible light and transmits light in the range of 600 to 700 nm. For illumination, LEDs can also be used. In order to avoid dazzling the driver, the light is passed through a grid structure so that it emerges directional. The mirror cover is not color matched to the LEDs used and not light scattering, but transparent. US 5,684,633 describes a polymeric body made of two polymeric materials of multilayer construction. It can z. B. more than 500 layers may be present. The polymeric bodies can be used for vehicle taillights and colored accordingly. The light sources are not further specified in this context. An adaptation of the colored cover to the spectrum of LEDs is not apparent.

EP-B-1456581 describes an illuminable device consisting essentially of a light source consisting of one or more light-emitting diodes (LEDs) emitting a colored, substantially monochromatic light and a light-scattering cover associated with the light source colored plastic. The cover has a transmission (DIN 5036) of at least 35% and a reflection (DIN 5036) of at least 15% at the wavelength of the relative energy maximum of the light-emitting diode. By the device is formed optically in about the same color impression in incident light, so z. B. in daylight, as well as fluoroscopy. Corresponding advertising or information boards appear optically approximately the same both during the daytime and in the backlit state (page 2, lines 34-50).

However, there is a need for an illuminable device, for example, for light advertising, the daytime in supervision (not backlit) for night effect (backlit) has different colors, for example, black during the day and a colorful color at night, for example, red. The device must be created so that, if possible, a black impression is given in supervision and still sufficient light passes through backlighting, however, to obtain a good view and an unimpaired color hue.

The spectral transmission in the wavelength range of 400-700 nm should be as constant as possible. The deviation from the mean spectral value should be below 5% points.

Furthermore, the device should allow low depths and be characterized by low power consumption The object is therefore to provide a device with the aforementioned property profile.

The device according to the invention solves this problem.

The invention relates to an illuminable device comprising at least one light source, a lower, the light source associated, light-scattering cover of colored colored (DIN 5033, Part 1) plastic, which at the wavelength of the relative energy maximum of the light source, a transmission (DIN 5036) of at least 35% and a reflection (DIN 5036) of at least 15%, and a top cover of a gray transparent colored plastic, which has a transmission of 5 to 20% at the wavelength of the relative energy maximum of the light source.

It is preferred that the light source of the device according to the invention consists of one or more light emitting diodes (LEDs) or fluorescent tubes, which emit a colored, substantially monochromatic light and show a particularly brilliant coloration. Most preferably, the use of one or more or a plurality of LEDs, which emit a colored, substantially monochromatic light. Optionally, LEDs of different colors can be used simultaneously.

The color of the LEDs depends on the wavelength of their relative energy maximum. This relative energy maximum can z. B. be determined spectrophotometrically and drawn in a wavelength spectrum. You can see the light source z. B. in a Ulbricht'sche ball (see DIN 5036) bring and measure the exiting light. The highest point (peak) of the curve indicates the wavelength of the relative energy maximum. The number of LEDs depends on the size of the device, the luminosity of the LEDs used and the overall desired brightness of the device in the illuminated state. LEDs are z. B are available as modules of 4 LEDs in a holder, of which, if necessary, a variety can be installed in the device. Suitable LEDs are z. B. red, blue, yellow or green LEDs.

A red LED has a relative energy maximum in the range of about 610 to 640 nm.

A blue LED has a relative energy maximum in the range of about 440 to 500 nm.

A yellow LED has a relative energy maximum in the range of about 570 to 610 nm.

A green LED has a relative energy maximum in the range of about 500 to 540 nm.

For combinations with several different colored parts e.g. Letters may alternatively include the usual white light sources, in particular e.g. Fluorescent tubes or white LEDs find use.

Particularly suitable for the lower cover made of plastic are tuned to the monochromatic light of the LEDs used colorful colorations, as they are characterized by a high light transmission with good light scattering. In addition, by such a colored lower cover, the light-reducing effect of the upper cover can be compensated.

The coloring of the device according to the invention, which appears black in supervision, is achieved by the neutral gray transparent coloring of the upper cover. In addition, the upper cover used in the invention has a transmission (DIN 5036) of 5 to 20%, preferably from 8 to 15%, at the wavelength of the relative energy maximum of the light source, so that when backlighting a good view is guaranteed and the hue of deposited lower colored layer remains virtually unchanged.

A gray coloration, which satisfies the above criteria can be, for example, by a mixture of soluble dyes, for example from the series of Macrolex ^® - (Lanxess), Sandoplast ^® - (Clahant) or thermoplastic ^® (BASF) - Farbstoffe_erreichen. Also by certain pigments such as specific soot pigments or spinel pigments, such as Pigment Black 26, is a coloring with the required properties possible.

Optionally, the device according to the invention may have a third layer between the lower and the upper cover which contains a colorless plastic. To increase the light scattering, this third layer may also contain scattering particles in an amount of from 0.1 to 10% by weight.

The lower and the upper cover as well as the intermediate layer are made of a plastic, which is transparent in the non-colored state and without scattering agent, or a transmission (DIN 5036, see parts 1 and 3 / D65) of at least 50%, preferably at least 70 , particularly preferably from 75 to 92%. With scattering agent (only lower cover and intermediate layer), but without colorant, the transmittance may preferably be at least 40%, more preferably at least 50%.

Suitable plastics are z. Polymethyl methacrylate plastic, impact modified polymethyl methacrylate, polycarbonate plastic, polystyrene plastic, styrene-acrylonitrile plastic, polyethylene terephthalate plastic, glycol-modified polyethylene terephthalate plastic, polyvinyl chloride plastic, transparent polyolefin plastic, acrylonitrile-butadiene-styrene ( ABS) -Ku nststoff or mixtures (blends) of various thermoplastics.

Because of their high weather resistance Polymethylmethacryat plastics, in particular for outdoor applications of cast or extruded polymethylmethacrylate, z. B. with a methyl methacrylate content of 85 to 100 wt .-%, preferably. Optionally, up to 15 wt .-% of suitable comonomers such as. Esters of methacrylic acid (eg, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate), esters of acrylic acid (eg, methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, cyclohexyl acrylate), or styrene and styrene derivatives such as a-methyl styrene or p-butyl methacrylate. Methylstyrene be polymerized or contained in the polymer.

The light scattering capacity of the lower cover and the intermediate layer, measured according to DIN 5036, preferably has a value of at least 0.5, especially preferably of at least 0.6, in particular at least 0.7. The better the light scattering capability, the smaller the distance of the light source from the cover and the associated lower overall depths of the device can be realized.

As a light scattering agent colorless scattering pigments are preferably used whose refractive index deviates to about 0.5 from the refractive index of the plastic, in particular to about 0.2 from the refractive index of acrylic glass. For example, calcium carbonate, magnesium carbonate, aluminum trihydroxide, magnesium hydroxide, barium sulfate, etc. are suitable.

Likewise, polymers which lie in the suitable refractive index range can be used. For example, in the methyl methacrylate monomer, polystyrene can be dissolved, which then precipitates during polymerization and results in a material with good light scattering. However, crosslinked polymer particles may also be added, e.g. Crosslinked polystyrene polymer beads or crosslinked copolymers of methyl methacrylate with phenyl (meth) acrylate or benzyl (meth) acrylate.

BaSO ₄ or polystyrene are preferred and are introduced in an amount of 0.5 to 5.0 wt .-%, preferably in an amount of 1, 5 to 2.5 wt .-% in the plastic. Lichtstreuperlen of a crosslinked plastic are preferably introduced in an amount of 0.1 to 10 wt .-% in the plastic.

At the wavelength of the relative energy maximum of a light-emitting diode, the lower light-scattering cover made of colored plastic exhibits a transmission (DIN 5036, see parts 1 and 3) of at least 35%, preferably at least 38%, particularly preferably at least 41% and a reflection ( DIN 5036, parts 1 and 3, reflection or remission) of at least 15%, preferably at least 20%, particularly preferably at least 30%.

The term "colored paint" is defined analogously to DIN 5033-1: 1979-03 (Part 1, Points 13 and 14). The transmission of a lower cover associated with a yellow LED can be at least 50%, preferably at least 60%. The corresponding reflection can be at least 25%, preferably at least 30%.

In particular, the transmission of a lower cover assigned to a red LED can amount to at least 40%, preferably at least 45%. The corresponding reflection can be at least 22%, preferably at least 45%.

In particular, the transmission of a lower cover assigned to a green LED can amount to at least 40%, preferably at least 42%. The corresponding reflection can be at least 18%, preferably at least 20%.

In particular, the transmission of a lower cover assigned to a blue LED can be at least 40%, preferably at least 42%. The corresponding reflection can be at least 20%, preferably at least 22%.

In the event that LEDs of different colors are used simultaneously to achieve mixed colors (eg, yellow and green LEDs produce a yellow-green color impression), the associated light-diffusing plastic cover should be at least at the wavelength of the relative energy maximum of one of the light-emitting diodes used , ie z. As the yellow or green LED, have the above required transmission and reflection values.

Suitable colorants for the lower cover are preferably organic colorants for the purposes of the invention, since they have high brilliance and luminosity both in incident light and in transmitted light. Suitable colorants are, in particular, plastic-soluble dyes or organic pigments, but also, less preferably, insoluble inorganic color pigments. To name a few are exemplary:

For yellow colorations: pyrazolone yellow or perinone orange or mixtures thereof. For red colorations: mixtures of pyrazolone yellow and anthraquinone red,

Naphtol AS or DPP red or mixtures thereof.

For green colorations: mixtures of Cu-phthalocyanine green and

Pyrazolone yellow.

For blue colorations: anthraquinone blue or ultramarine blue or

Mixtures thereof.

The preparation of the cover plates contained in the device according to the invention can be carried out in a conventional manner by extrusion or injection molding. The two-layer system is preferably prepared by coextrusion. In the production by injection molding, preferably, the top cover and the colored bottom cover plate are made separately.

According to a particular embodiment, a chamber is formed from the lower and the upper cover plate, into which subsequently a liquid colorless plastic is poured, which then hardens to form a third connecting layer.

Dispersants and colorants may be added or incorporated into the plastic in a manner known per se during the polymerization or during the thermoplastic processing in the melt state. To protect the plastic against the effects of light and weather, light stabilizers, UV absorbers, antioxidants, etc. can be added.

In this way, for. B. plastic plates with a thickness of z. B. 0.5 to 10 mm, preferably 1 to 5 mm, can be obtained, which can be used as covers for illuminable devices according to the invention with rectangular boxes, frame or holder. Corresponding pieces can be converted and adapted as required by cutting, milling, sawing or other processing in virtually any shape and adapted. In addition to the plate shape, any profiles, such as pipes, rods, etc. can be manufactured.

In the case of the use of LEDs, the device according to the invention can be designed such that the spacing of the LEDs diffuses to the lower light Cover 3 to 12 cm, preferably 4 to 10 cm. At this distance a good illumination is achieved. If the distance is too short, the position of the LED will be visible as a bright spot. If the distance is too great, the brightness decreases too much.

The LEDs can z. B. in a box or frame, which is covered by the lower and upper cover. The covers may be provided with an information-bearing layer, e.g. As a film provided or even already have the form of information, for. B. in letter or number form.

The device according to the invention is preferably used as an advertising or information board.

Example:

Three layer device

Gray cover:

Version 1 :

In 1000 parts prepolymer Metylmethacrylat syrup (viscosity about 1000 cP) is

1 part of 2,2'-azobis- (2,4-dimethylvaleronitrile) dissolved.

In this approach, one gives a color paste consisting of

3 parts of a soluble polymethyl methacrylate resin and

0.2 parts of Pigment Black 26, which in

30 parts of methyl methacrylate with a high-speed dispersant

(Rotor / stator principle) is dispersed, added.

The mixture is stirred intensively, in a distanced with a 3 mm thick cord

Silicate glass filled and polymerized in a water bath at 45 ° C for about 16 hours polymehsiert. The final polymerization is carried out in a tempering at 115 ° C for about 4 hours.

This gives a plate with a neutral gray, transparent appearance.

The spectral transmission is in the wavelength range of 400-700 nm at 10 bis

15%. The transmittance is 12%. Variant 2:

In 1000 parts prepolymer Metylmethacrylat syrup (viscosity about 1000 cP) is

1 part of 2,2'-azobis- (2,4-dimethylvaleronitrile) dissolved.

In this approach, one gives a mixture

0.0060% Macrolex green G,

0.0040% Macrolex Violet B

0.0067% Plastred 8350 and

0.0028% thermoplastic yellow 104 added

The mixture is stirred intensively, in a distance with a 3mm thick cord

Silicate glass filled and polymerized in a water bath at 45 ° C for about 16 hours polymehsiert. The final polymerization takes place in a Temperschrank at 115 ° C for about

4 hours. This gives a plate with a neutral gray, transparent

Appearance.

The spectral transmission is in the wavelength range of 400-700 nm at 7

17%. The transmittance is 12%.

Colored cover of one color of the colorant series 1:

Production analogous to gray cover, but it will consist of a color paste

3 parts of a soluble polymethylmethacrylate resin,

20 parts of barium sulfate and the colorants of the respective color according to Table 1, which in

30 parts of methyl methacrylate with a high-speed dispersant

(Rotor / stator principle) is added.

Tab. 1

Colorant Series 1: Red 1, Yellow 1, Blue 1 Green 1

Data: in% by weight

Inside:

Manufacture analogous to gray cover, but it will replace the

Color paste consisting of a paste

3 parts of a soluble polymethyl methacrylate resin and

10 parts of barium sulfate, which in

30 parts of methyl methacrylate with a high-speed dispersant

(Rotor / stator principle) is added.

The mixture is stirred intensively, in a distance with a 3mm thick cord

Chamber filled, which is formed of the gray and one of the colored covers _^ and polymehsiert in a water bath at 45 ° C for about 16 hours. The

Final polymerization is carried out in a tempering at 115 ° C for about 4 hours.

This gives a three-layer cover plate.

Results:

In a white lacquered, open top metal box measuring 90 x 470 mm and

100mm height are 32 light-emitting diodes on the inner bottom, from OSRAM (8

Module ä 4 LED's) attached. With a power supply, the permissible operating current of between 320 and 400mA is set at an operating voltage of 10V, depending on the type.

One of the previously obtained three-layer cover plates is placed with the gray side up on this box and judged by color. The incident light test

(Daytime effect) is achieved by illumination with a daylight lamp with 150 W (D65 according to DIN 6173, quality class 1, eg from Siemens) at a distance of approx. 60 cm from above. The LEDs are switched off. The transmitted light test takes place in one darkened room with activated LEDs according to the above operating information.

The daytime effect is neutral black in the device according to the invention. In the case of fluoroscopy (night-time effect), a clear and brilliant coloring (red, yellow, green and blue after series 1) can be recognized, depending on the version.

Claims

claims:

1. Illuminable device comprising at least one light source, a lower, the light source associated, light-scattering cover of colored (DIN 5033) plastic, which at the wavelength of the relative energy maximum of the light source, a transmission (DIN 5036) of at least 35% and a Reflection (DIN 5036) of at least 15%, and a top cover made of a gray transparent colored plastic, which has a transmission of 5 to 20% at the wavelength of the relative energy maximum of the light source.

2. Apparatus according to claim 1, characterized in that the light source consists of one or more light emitting diodes (LEDs) or fluorescent tubes emitting a colored, substantially monochromatic light.

3. Apparatus according to claim 1 or 2, characterized in that the transmission of the upper cover is 8 to 15%.

4. Device according to one or more of claims 1 to 3, characterized in that the upper and lower cover are connected directly to each other.

5. Device according to one or more of claims 1 to 3, characterized in that there is a third layer between the lower and the upper cover, which contains a colorless plastic.

6. Device according to one or more of claims 1 to 5, characterized in that the plastic is polymethylmethacrylate.

7. The device according to claim 5, characterized in that the third layer additionally contains light scattering agent in an amount of 0.1 to 10 wt .-%.

8. Device according to one or more of claims 1 to 7, characterized in that the light source is in a box or frame, which is covered by the lower and the upper cover.

9. Use of the device according to one or more of claims 1 to 8 as an advertising or information board.