ITTV20100123A1 - THIN-THICK RETRO-LIGHTING DEVICE FOR INTERIOR CAR LUMINOUS COMPONENTS, WITH A LED LIGHT SOURCE AND WITH IMPROVED LIGHT DISTRIBUTION OF THROUGH A LIGHT VARIABLE SECTION AND ELLIPTICAL MICRO-OPTICAL SECTION SUPER - Google Patents

Description

RETR01LLUM1NANTE DEVICE WITH THIN THICKNESS TOP

FOR BRIGHT COMPONENTS OF CAR INTERIORS. WITH SOURCE

BRIGHT LED AND WITH IMPROVED LIGHT DISTRIBUTION

FOR USING A VARIABLE SECTION LIGHT GUIDE E

ELLIPTICAL MICRO-OPTICS WITH SUPERFICIAL WHEELBASE

VARIABLE

The present invention relates to a thin-thickness flat back-lighting device for luminous components of car interiors, for example footsteps with a luminous distinctive emblem or decorative luminous escutcheons, with a LED light source and with improved light distribution by means of a guide - variable section light and surface elliptical micro-optics with variable center distance.

State of the art

Various thin, substantially flat devices for backlighting are well known in the electronics sector, in particular in LCD type displays, and also in the automotive sector, in particular in the dials in instrumentation, in signaling devices and in aesthetic profiles with decorations. or bright emblems.

In general, the most popular backlighting technologies can be grouped into three distinct types:

guide - traditional light, otherwise known as "light pipe" or "light guide" in English, made of transparent thermoplastic polymer with optical qualities, generally Polycarbonate or Polymethylmethacrylate, and shaped in such a way as to conduct the light where required, even planarly , plate-shaped and superficially equipped with integrated optical elements, such as microprisms, microlenses, hemispheres, grooves or even simple surface roughness, designed in such a way as to allow the light rays to exit the solid body in the desired direction, usually towards the upper face. In these devices the light source is constituted by one or more LED diodes, sometimes neon, placed on the side in such a way as to direct the light rays longitudinally inside the solid body of said light guide. Sometimes there are underlying layers of reflective material in such a way as to redirect the light rays towards the lower surface, or there are layers of opalescent translucent material on the top, suitable for improving the distribution of the light emitted;

electroluminescent film, thin and flexible in the luminous part, substantially a multilayer device, sealed, containing the material with electroluminescent properties and also the various layers for the correct distribution of light, which requires a transformer and a separate electronic control;

• optical fiber “pad”, made from a plurality of superficially micro-furrowed optical fibers, placed side by side and glued on a reflective flexible support. The light source is constituted by an LED diode equipped with a concentrating lens able to convey the light rays inside the cord formed by the collected fibers; said rays come out of the micro-grooves distributed on the upper surface of said "pad" in proximity of the area to be backlit.

In general, the main quality parameters with which backlight devices are evaluated are:

quantity of light emitted by a surface, otherwise called luminance and measured in cd / m2; in particular, in the automotive sector, the maximum and minimum luminance values relating to some components are regulated;

* homogeneity of the light emitted, ie the distribution of luminance values in the various parts of the device; in particular it measures the variation of the values relating to a portion of the surface with respect to the others;

maintenance of quantity and homogeneity values over time and under certain conditions such as, for example, high humidity and temperature.

It is known that electroluminescent film and optical fiber solutions are sometimes problematic in maintaining performance over time or under certain conditions, while light guide solutions have numerous advantages, including low cost, but are sometimes problematic in uniform distribution of the light. light emitted. The solution described by the invention falls within the light-guide type with specific measures designed to improve the distribution of light on the illuminating surface. In order to determine the state of the art of this solution, a research was conducted which identified the following prior documents: DI: US20060268551 (Mok et al.) - Avago Technologies

D2: US6827457 (Umemoto et al.) - Nitto Denko

D3: US5050946 (Hathaway et al.) - Compaq

D4: US5608550 (Epstein et al.) - Minnesota Mining

D5: US566891 3 (Tai et al.)

D6: US7039286 (Leu et al.) - Hon Hai Precision Ind.

D7: US71 14820 (Parikka et al.) - Nokia

D8: US6402334 (Yu-San et al.) - Garmin

D9: US20080089654 (Lee et al.) - LG

D1 0: EP1 890077 (Haase et al.) - Hella

D1 describes a typical backlighting device for LCD displays and also proposes an improved version characterized by a plurality of "LED dies" type light sources aligned and encapsulated in a flexible printed circuit support and where the illumination is distributed by a guide - flat and transparent light characterized by a lower and an upper surface that reflect and convey the rays emitted by the light sources located on the side and where the lower surface includes reflective elements capable of redirecting the light rays at an angle that exceeds the critical angle and exit from the upper surface; said reflecting elements can be suspended inside the plastic material with which the light guide is made or placed on the lower surface of the same. A reflective film is placed under the lower surface of the light guide; similarly, in proximity to the light sources, a flexible reflective film is placed on top which redirects the outgoing light rays inside the optical system.

D2 describes a reflective backlighting device for LCD displays, devoid of the visual disturbances and moiré effect typical of the images produced by backlit displays with microprism diffuser, and where the light guide used is improved and characterized by a particularly light distribution. efficient. In particular, the system includes a flat light guide where in the surface opposite to the illuminating one there are integrated micro-grooves arranged in a discontinuous way, where said micro-grooves have a length not exceeding 250μΐη and a depth not exceeding 50 μΐη and the triangular section of the groove with the side inclined towards the light source having a variable angle between 35 and 48 degrees. In particular, said micro-grooves are arranged with a higher density away from the light source. The light source, for example LED, is located on the side.

D3 describes several known configurations of backlighting devices for LCD displays and proposes a new improved configuration characterized by a variable section light guide with lateral light source, where the illuminating surface is flat and the opposite one is faceted with reflective inclined steps which progressively reduce the section. Said stepped facets can optionally be concave or convex and also with surface roughness if necessary to improve light distribution. In a preferential configuration, a layer of reflective material is placed under the variable section surface and above, between the flat illuminating surface and the display, a layer of diffusive material.

D4 suggests a front lighting system of LCD display based on a guide - light illuminated laterally and characterized by a surface with a plurality of inclined planes reflecting inwards obtained with micro grooves or notches, where the frequency of these optical elements it is not uniform but increases away from the light source; substantially the increase in the density of the reflecting elements compensates for the decrease in the luminous flux. In a variant embodiment, the inclined planes are obtained by means of steps which, moving away from the light source, progressively reduce the section of the solid.

D5 describes a flat lighting device characterized by a flat light guide with raised, continuous and transversely arranged microprisms, shaped in various ways, for example with triangular, trapezoidal section, portion of a circle, convex lens with an inclined axis; where the light source is lateral. The device is intended to illuminate displays, traffic signs, medical instruments, measuring instruments, jewelry, art images or as a transparent lighting tool through which to look during surgical or dental operations.

D6 proposes a thin and flat lighting device, substantially consisting of a lateral light source and a plurality of reflective and diffusive organic spheres integrated on the upper surface by means of a binding adhesive agent and where the lower surface and also the lateral one opposite the surface inlet of the luminous flux are coated with a layer of reflective circular elements. In an alternative embodiment configuration, the reflecting circular elements can advantageously increase in diameter by progressively moving away from the light source.

D7 describes a method of surface texturing of a thin light guide for flat screen displays which allows to obtain a better uniformity in the distribution of light and which is extremely simple to manufacture. Basically it proposes to divide the upper surface, illuminating, into a plurality of minimum surface units, whose diffractive properties vary according to the orientation and where the texturing is carried out by mold directly on the surface. In a preferential embodiment configuration the illuminating area is divided into a matrix of small squares with microcrests of type B, longitudinally oriented in the direction of the propagation of light, or of type A, oriented transversely in the opposite direction; the choice of increasing the density of type A units by gradually moving away from the light source increases the amount of rays emitted from the surface and compensates for the decrease in light intensity, D8 proposes a backlight device for displays where the light guide is characterized by a plurality of hollow surface optical elements, reflecting and diffusing, in the shape of a quarter of a sphere and longitudinally aligned. In an alternative configuration, said optical elements remain longitudinally aligned but, moving away from the light source, they decrease the center distance and increase the dimensions so as to compensate for the decrease in light intensity and improve its uniformity.

D9 describes a cylindrical and hollow light guide, with the internal surface structured with continuous triangular prisms arranged longitudinally and with the external surface equipped with micro-optics in relief, reflecting and diffusing, arranged with a regular center distance, suitable for causing the exit of the light and also diffuse it homogeneously. In an alternative configuration with improved light distribution, said surface micro-optics have an annular arrangement with decreasing center distance moving away from the light source, located at the end; this arrangement allows to progressively increase the quantity of light rays emitted by the cylinder, per surface unit, away from the light source, to compensate for the decrease in intensity of the same and to obtain a lighting device with constant luminance values and homogeneous light distribution. In an alternative embodiment configuration, the reflecting and diffusive elements are integrated in a film adhering to the internal surface and have variable diameters and center distances in such a way as to increase and proportion the density of the emitted rays with the distance from the source.

DI O describes a light profile for cars, with a curved and thin shape, made with a traditional light guide, where the point light source is positioned at the top and where the external surface is smooth, with a substantially semicircular section, and the surface lower is faceted and reflective by means of continuous transversal prisms suitable for creating a plurality of inclined planes reflecting the light rays towards the outside; the proposed device is characterized by a substantially tapered longitudinal section moving away from the light source. It is therefore reasonable to believe that a backlighting device structure for luminous signaling components or displays is known, consisting of:

• Guide - substantially flat light, illuminated laterally, which superficially integrates a plurality of optical microelements able to reflect and diffuse the light rays, where said optical microelements are geometrically shaped in various ways including, for example, spheres, hemispheres, quarter spheres ; triangular, trapezoidal, semicircular section prisms; embossed or hollow; continuous or discontinuous; with micro-grooves, micro-crests or with simple surface roughness.

• Guide - light characterized by said optical microelements arranged on the upper or lower surface and also combined, for example above to diffuse and below to reflect; and where the distance between said elements and also the dimensions are variable according to the distance from the light source, they generally increase progressively.

■ Guide - light characterized by a flat emitting surface and by the opposite surface with inclined planes obtained by means of steps which, moving away from the light source, progressively reduce the section of the solid.

* Guide - light made monobloc with injection molding technology in a transparent thermoplastic polymer for optical use such as, for example, Polycarbonate, Polymethylmethacrylate, “Methallocene Cyclic Olefin” copolymer. • Lateral light source composed of a LED or a plurality of aligned LEDs, possibly with a front optical interface element to uniform the flux before being conveyed inside the light guide.

* Any underlying reflective layers and any upper diffusive layers, between the light guide and the component to be illuminated.

Drawbacks

The proposed and known solutions have some drawbacks.

The main problem to be overcome is the uneven distribution of the light emitted substantially due to the decrease in light intensity as a function of the distance from the light source and also to the difficulty of managing the reflected rays, even of various inclinations, and emitting them through the illuminating surface in uniform way. Known optical systems generally require layers of diffusive material interposed between the illuminating surface and the component to be backlit, which are expensive and bulky. Other systems provide for the gluing of diffusive elements on the surface, for example microspheres, others the insertion of reflecting elements in suspension, with the manufacturing problems and costs that these solutions entail.

All this considered, it is reasonable for companies in the sector to identify innovative solutions capable of overcoming at least the problems noted above, that is, to create an extremely simple device, characterized by an improved uniformity of the light emitted and a low cost.

Summary of the finding

The present invention relates to a thin-walled back-lighting device for luminous components of car interiors, for example water heaters with a luminous distinctive emblem or decorative luminous escutcheons, with a LED light source and with improved light distribution by means of a light guide. with variable section and surface elliptical micro-optics with variable center distance.

Aims

In this way, through the notable creative contribution whose effect constitutes an immediate and not negligible technical progress, different and remarkable aims are achieved.

A first object consisted in realizing a back-lighting device with excellent characteristics in terms of uniformity in the distribution of light and made with the least number of components.

A second purpose consisted in realizing a backlighting device with an extremely limited thickness, which can be completely and easily integrated into the components for car interiors, for example the door sill guard or the decorated escutcheons for dashboards and door panels.

A third object consisted in realizing a backlighting device which is extremely simple in construction and assembly.

A fourth object consisted in realizing a self-supporting backlighting device which incorporates seats and fixings.

A fifth purpose consisted in realizing a backlighting light guide device with improved performances capable of replacing similar systems based on electroluminescent films or on optical fibers.

A further object consisted in realizing a back-lighting device with an extremely low cost.

Description

The invention describes a new backlighting system for decorative components for car interiors, for example a plastic or metal kick plate with a transparent central distinctive logo and backlit with colored light, where the backlighting is carried out by means of a thick flat light guide. thin with LEDs positioned on the side, and where said light guide is shaped with a variable section decreasing with respect to the light source to keep the amount of light constant and homogeneous over the entire surface and with elliptical micro-optics in relief on the lower surface to give greater uniformity to the light. The same device can also be applied for the backlighting of internal escutcheons or decorative profiles.

Claims (4)

CLAIMS 1. Lighting device with thin thickness and uniform light distribution, suitable for the backlighting of components for car interiors, consisting of a light guide with a flat conformation and a lateral LED light source, characterized by the fact that said light guide integrates on the lower surface a plurality of raised elliptical micro - optics suitable for reflecting and diffusing the light rays upwards; and where said lower surface has a variable section, decreasing aliontanadosi from the light source; and where said elliptical micro-optics have variable center distance, decreasing aliontanadosis from the light source; and where said elliptical micro-optics have variable dimensions, increasing aliontanadoses from the light source; and where the upper surface has a micro-roughness suitable for attenuating any variations in intensity visible on the illuminating area. 2. Illuminating device as per claim 1, characterized in that said light guide with variable section with elliptical micro-optics is of the monobloc type, integrates seats and fixings; and where said light guide is made with injection molding technology in a transparent thermoplastic polymer for optical use. 3. Illuminating device according to claims 1 and 2, characterized in that it can be integrated into a thin-thickness sill scuff plate and with decorated and distinctive luminous-type parts. 4. Illuminating device according to claims 1 and 2, characterized in that it can be integrated into a decorative flange with a thin thickness and with parts of the luminous type.