DE29815437U1 - Radiolucent component for devices with backlighting - Google Patents

Description

Transmissible component for devices with backlight

The invention relates to a component for use in devices with background lighting, wherein a light source is arranged inside the device, which at least partially shines through the component, the light emerging from the component in a scattered manner.

Such components are used in a wide variety of ways. For example, they can be displays for pocket calculators 10 or panels and switches for car radios. Such components are also used as switch arrangements with background lighting for use in vehicle passenger compartments.

Actuating switches are used in motor vehicles for a wide variety of electrical devices (lights, windscreen wipers, window lifters, radio, etc.). A light source in the form of a lamp or a light guide is integrated into the device, for example the switch or the radio, for background lighting. When the vehicle lights are switched on, the background lighting is also switched on. The light emerges from the component (cover element) via the symbols on the actuating switch, so that the switch can be activated via the illuminated symbol.

Hanover:

Koblenzer Straße 21 D-30173 Hannover Federal Republic of Germany Telephone 0511 / 988 75 07

Please reply to:

Brunswick:

Theodor-Heuss-Straße 1 D-38122 Braunschweig Federal Republic of Germany Telephone 0531 / 28 14 0-0 "5ele/9x_D531 / 28 140 28

can also be identified in the dark (night design). To ensure that the switch can be clearly identified during the day, the symbols must be clearly distinguished in color from the rest of the outer surface of the cover element (day design).

In order to achieve a level of illumination that is pleasant for the human eye and to prevent the light source from being visible through the component, the emerging light must be strongly scattered.

In order to achieve the scattering, light distribution paints are currently sprayed onto the back of the component, which faces into the device. Spraying the paints sometimes requires a high level of expertise in order to achieve an even layer of paint, even on components with complex shapes. Surfaces that serve as reference or contact surfaces are often not allowed to be wetted with paint, so a corresponding template must be made beforehand.

It is also known to stick light distribution foils onto the back of the components. This additional work step not only makes the component more expensive, but also increases the production time.

In many cases, the components are tinted in order to conceal irregularities in the surface of the component. However, it must be accepted that each color pigment reduces the light passing through the component and therefore the light source intended for the background lighting must be amplified. The costs of stronger light sources are, however, much higher than the costs of spraying or sticking a surface.

Based on this problem, the component described at the beginning is to be improved with regard to its translucency and suitability to refract light.

To solve the problem, the component is made of plastic and irregularly distributed glass beads with a diameter of 6 to 8 μια are mixed into the plastic, with the proportion of glass beads being 0.5% to 20%.
5

This design improves light scattering by almost 50% compared to previous solutions. The glass spheres have very good permeability, so that either fewer light sources are required or the quality of the light output is improved compared to previous systems.

The glass balls can be hollow or solid.

The surface of the glass beads is preferably provided with an oxide layer in order to achieve a void-free cross-linking with the plastic.

The plastic is preferably crystal clear to achieve maximum light transmission. 20

The invention will be explained in more detail below with the help of the attached drawing. It shows:

Figure 1 - the schematic representation of the irradiation of a component according to the invention;

Figure 2 - the schematic representation of the irradiation of a conventionally designed component.

As Figure 2 shows, 6 different light-emitting diodes 2 are arranged in a device, which shine through a translucent component 1 (for example a display panel or an actuating switch). In order to achieve the greatest possible light intensity, the component 1 is not or only slightly colored, the light refraction is weak and, as can be seen from the illustration, the diodes 2 are visible from the outside.

Figure 1 shows a component designed according to the invention, which consists of plastic, preferably crystal-clear polycarbonate, which has a very high heat resistance. Micro hollow or solid glass spheres 4 are mixed into the plastic in an irregularly distributed manner. The glass spheres have a diameter of 6 to 8 μm and are manufactured, for example, by the US company Balodini. The light is refracted very strongly by these glass spheres 4, so that the light rays 3 emerge from the component 1 very diffused. The illumination is therefore very uniform, the diodes 2 cannot be seen from the outside.

An oxide layer (not shown here) is applied to the surface of the glass beads 4, which is tailored to the respective basic material type of the thermoplastic and serves to achieve void-free cross-linking with the base material. The proportion of glass beads 4 in the component 1 is variable in a range from 0.5% to 20% and depends on the application.

Claims (5)

1. Component for use in devices with background lighting, wherein a light source is arranged inside the device, which at least partially shines through the component, the light emerging from the component in a scattered manner, characterized in that the component ( 1 ) consists of plastic and glass beads ( 4 ) with a diameter of 6 to 8 µm are mixed into the plastic in an irregularly distributed manner, and that the proportion of glass beads ( 4 ) is 0.5% to 20%. 2. Component according to claim 1, characterized in that the glass balls ( 4 ) are hollow. 3. Component according to claim 1, characterized in that the glass balls ( 4 ) are solid. 4. Component according to claim 1, characterized in that the surface of the glass beads ( 4 ) is provided with an oxide layer for void-free cross-linking with the plastic. 5. Component according to one or more of the preceding claims, characterized in that the plastic is crystal clear.