WO2020141450A1

WO2020141450A1 - Optoelectronic device of the led (light emitting diode) type or the like

Info

Publication number: WO2020141450A1
Application number: PCT/IB2019/061458
Authority: WO
Inventors: Marco FRANCIOSA; Andrea TELLATIN
Original assignee: Ledworks Srl
Priority date: 2019-01-03
Filing date: 2019-12-31
Publication date: 2020-07-09
Also published as: IT201900000058A1

Abstract

Optoelectronic device of the LED (light emitting diode) type or the like, comprising at least two emitters (20,21,22), the at least two emitters are contained within an outer transparent envelope (12), so as to allow the passage of the light generated by said at least two emitters. Each emitter is configured in such a way as to emit a source of white light, each at a different colour temperature.

Description

OPTOELECTRONIC DEVICE OF THE LED (LIGHT EMITTING DIODE) TYPE OR THE LIKE

DESCRIPTION

The present invention relates to an optoelectronic device of the LED (light emitting diode) type or the like, comprising at least two emitters, which are contained within an outer transparent envelope, so as to allow the passage of the light generated by said at least two emitters .

Preferably the invention relates to addressable LEDs, i.e. LEDs that are configured so as to receive instructions for driving the light intensity to be emitted, together with further command data, sent by a control unit connected to said LEDs .

The one just described is the common configuration of LEDs known to the state of the art, such as for example, the well-known RGB (Red, Green and Blue) LEDs, i.e. LEDs that have three emitters, in particular an emitter capable of emitting a red light, an emitter capable of emitting a green light and an emitter capable of emitting a blue light .

By mixing the colours emitted by the three emitters, it is possible to obtain different possible colours, especially thanks to the presence of opaque, translucent (or slow) envelopes, which allow to obtain a homogeneous mixture of the three colours to generate a single colour.

Despite the different LED driving algorithms known to the state of the art and despite the technological development of both the emitters and the lenses, some users ' needs still remain unsatisfied, especially related to obtaining particular effects, such as particularly brilliant and bright colourings .

For example, with the LEDs known to the state of the art, the most different colourings can be obtained, both in terms of lightness brightness, but the effects are limited to the colours that derive from a mixture of red, green and blue colours .

Although in theory it is possible, with appropriate mixing of the primary colours red, green and blue, to obtain any colour of the visual spectrum, it is not possible to obtain this result in practice with individual LED lights, since, the greater the need to mix the colours, the greater is the quantity of opaque material needed and requires an opaque envelope that prevents brightness and makes the colour homogeneous and unchanging as the observer ' s point of view changes .

In fact, the present invention has the purpose of realizing a LED capable of emitting a light source that can recreate a "metallic" effect, i.e., of emitting a light with a mixture of colours and a level of brightness such as to recreate effectively the colour of the metals, such as gold, silver, copper, bronze.

The present invention achieves the above objects by realizing a device as previously described, wherein each emitter is configured in such a way as to emit a white light, of varying intensity, each at a different colour temperature .

As known to the state of the art, it is specified that the term colour temperature is used in lighting technology, photography and other related disciplines to quantify the light shade, it is measured in kelvin (https : //it .wikipedia.org/wiki/Temperatura_di_colore)

The proper mixing of the different light sources allows the device object of the present invention to reproduce a light similar to that reproduced by an illuminated metal . The presence of at least two emitters in conjunction with the fact of emitting white light at different temperatures is crucial, as it allows to obtain an effect of chromatic variability and separation based on the position of the observer, a typical effect of metals.

Therefore, the metallic effect is obtained through the mutability of the LED lighting effect based on the position of the observer, just to recreate the typical brightness of metals.

As will be specified later, to obtain this effect, the contributions of each light source must be different .

For this reason, the term "mixing" is intended as a union, i.e., as the simultaneous emission of two light sources, but these light sources do not mix and do not get confused to create a homogeneous light effect, but the individual contributions are easily distinguishable .

Moreover, the realization of a LED with at least two emitters that emit a different white light is a particularly complex industrial process.

In fact, unlike RGB LEDs, to obtain a white light, it is necessary to deposit phosphorus powders on the emitters, in different quantities, to obtain the different white temperature desired. Within a particularly restricted space, such as the one available inside the outer envelope of LEDs known to the state of the art, it is not possible to obtain a precise deposition of the phosphorus powders and there is a risk that part of the phosphorus powders relative to one emitter, are deposited on another emitter, compromising the success of the LED.

According to a preferred embodiment, the device object of the present invention provides for the presence of three emitters .

Again, each emitter is configured to emit a white light source of varying intensity, each at a different colour temperature .

Preferably an emitter emits warm white light (Warm White) , an emitter emits cold white light (Cold White) and an emitter emits amber light (Amber) .

In order to obtain these different colourings, a first emitter emits light at a temperature between 5000 and 6000 K, a second emitter emits light at a temperature between 2400 and 3000 K, a third emitter emits light at a temperature between 2000 and 2400 K.

The mixing of these different colours allows the LED object of the present invention to generate a metallic effect, i.e. the light emitted is of the correct shade and adequately bright that it can be compared to a metallic light, in particular to the light generated by a metal that is enlightened.

Advantageously, the generated light consists of mixing the light sources emitted by at least two of said three emitters .

In fact, according to the particular type of metal that is usually obtained, the contributions of the different emitters will be modified, and even only through the combination of two emitters is it possible to obtain the desired metallic effect.

In particular, some possible configurations of the contributions of each emitter are described below, based on the metal chosen :

Silver: 70-85% Cold White, 10-20% Warm White

Yellow gold: 90-100% Warm White, 10-20% Amber

Pink gold: 80% Warm White, 40-50% Amber

Copper: 80% Amber, 20-30% Warm White, 5% Cold

White

Bronze: 100% Amber, 10% Cold White.

According to a preferred embodiment, the outer envelope is constituted, at least in part, by a transparent glossy material.

As anticipated, the presence of transparent glossy material allows to filter the light sources, keeping the contributions of each single emitter separate, without mixing them to generate a homogeneous light effect .

In order to further increase the brightness of the light source, and to partially separate the chromatic components, according to an embodiment, it is possible to provide that the outer envelope comprises a concave lens arranged perpendicular to the light beam emitted by the emitters and therefore to the metal base of the device on which the emitters are arranged parallel .

This lens therefore has a surface with a concavity facing the emitters .

Advantageously, the lens is made of transparent glossy material.

The presence of several emitters turned on at the same time and the concave and transparent lens, allows to radiate the light separating the colours, in order to give that feature of chromatic mutability to the point of view shift of a possible observer, typical of metal .

The device object of the present invention therefore provides a lens capable of maximizing the brightness of the light emitted by the emitters and which does not merge the colours but keeps them separate .

This feature is particularly different compared to the well-known RGB LEDs which require an opaque lens to mix the colours emitted by the emitters : the purpose of the state-of-the-art LEDs is in fact to obtain a homogeneous mixing and not a changing colour, making the use of opaque lenses necessary.

According to an embodiment of the device object of the present invention, the outer envelope is constituted by a cylindrical element which has a transparent side wall and a transparent lens arranged at the upper base, of convex shape.

As anticipated, one of the peculiarities of the device object of the present invention is the possibility of realizing a LED which has three emitters, each of which has a different quantity of phosphorus powders inside an outer envelope which has a particularly limited space .

For this reason, the outer envelope advantageously has a section of less than 14 square millimetres.

Given the advantageous aspects of the device just described, the present invention also relates to a method for the generation of a light source suitable for recreating a metallic appearance colour.

By a metallic appearance colour, we mean, as previously described, a particularly bright colour, with a specific set of suitable shades and with the mutability feature necessary to represent a metallic effect .

In fact, the metallic effect is such that the generated light must have a chromatic variability according to the observer ' s point of view and must be bright .

Advantageously, the method uses the device object of the present invention, i.e. the LED described above, with all the features treated.

Through the use of said LED, the method object of the present invention provides that the generation of said light source provides for the simultaneous activation of at least two of the emitters, the light sources of each emitter being filtered by an outer envelope of transparent glossy material, in order to recreate the chromatic mutability feature based on the position of an observer.

As anticipated, for example, to generate a "silver" effect it is sufficient to activate only two emitters, the one with warm white light and the one with cold white light .

In this case the dominant shade will be the cold white light, typical of silver, and the warm light shade will give the most typical reflections of that material .

As anticipated, the generation of the light source requires that each emitter emits white light at a different colour temperature.

Finally, according to a preferred embodiment, the generation of said light source is obtained by mixing the light sources emitted by said three emitters, according to predetermined percentages based on the metallic effect to be recreated.

It is evident that the method object of the present invention, in order to recreate the desired metallic effect, provides to use correct chromatic sources, to choose the appropriate white temperatures of the emitters and to choose the appropriate ignition proportions to make the colour suitable .

These and other features and advantages of the present invention will become clearer from the following description of some exemplary embodiments illustrated in the attached drawings wherein:

figures la and lb show a concept diagram of a possible embodiment of the device object of the present invention .

It is specified that the figures attached to the present patent application show a preferred embodiment of the device object of the present invention to better understand its advantages and features described.

This embodiment is therefore to be intended for purely illustrative and non-limiting purpose to the inventive concept of the present invention, i.e. that of realizing an LED capable of generating a light that presents a metallic appearance colour.

In particular, figures la and lb show an LED 1 which has a base 10 with a metal support plate 11 on which three emitters 20, 21 and 22 are fixed.

There is also an outer envelope 12 consisting, at least in part, of a transparent cylindrical element, which has a lens 13 at the upper base .

Advantageously, it is precisely the lens 13 which is made of transparent glossy material. The lens 13 has a concavity facing towards the metal plate 11, so as to be substantially perpendicular to the beams of the light sources A, B and C emitted by the three emitters 20, 21 and 22.

With particular reference to the variant embodiment illustrated in the figures, it is specified that the lens 13, of which a section is illustrated in figure la, has a conical shape, with the top facing towards the emitters 20, 21 and 22.

The emitter 20 emits a beam A consisting of a "cold white" light radiation (colour temperature between 5000 and 6000 K) , the emitter 21 emits a beam B consisting of a "warm white" light radiation (colour temperature between 2400 and 3000 K) , while the emitter 22 emits a beam C consisting of an "amber" light radiation (colour temperature between 2000 and 2400 K) .

For illustrative simplicity, figure la illustrates the device object of the present invention without showing the diffusion of light, while figure lb illustrates in particular how the light is diffused by the LED object of the present invention, once the flows A, B and C pass through the lens 13.

As can be seen from Figure lb, the light emitted by the LED 1 consists of a mixing of the beams A, B and C, variable according to the proportions of the three beams, as described above, in order to obtain a specific metallic colour.

As anticipated, by mixing we mean the simultaneous emission of the light sources emitted by the three emitters, but we do not mean a homogenization of the three light beams, since the contributions of each individual emitter remain distinct by an observer. As illustrated in figure lb, the three beams A, B and C impact with the surface of the lens 13 and the particular shape of this lens 13 allows to diffuse the light in all directions, as illustrated in figure lb.

The light diffusion is such that the intensity, lightness and brightness of this light are variable based on the position of a possible observer, in order to recreate the typical effect of metallic materials.

In order to recreate this effect, as previously described, the simultaneous activation, even with different contributions, of at least two of the three emitters 20, 21 and 22 is sufficient.

Finally, it is specified that the three emitters 20, 21 and 22 can be arranged in any way known to the state of the art on the metal support plate 11, without modifying the light effect of the LED object of the present invention.

While the invention can be changed according to different modifications and alternative constructions, some preferred embodiments were shown in the drawings and described in detail .

It should be understood, however, that there is no intention of limiting the invention to the specific illustrated embodiment but, on the contrary, it aims at covering all modifications, alternative constructions, and equivalents falling within the scope of the invention as defined in the claims .

The use of "for example", "etc.", "or" indicates non-exclusive alternatives without limitation unless otherwise indicated.

The use of "includes" means "includes but is not limited to" unless otherwise indicated.

Claims

1. Optoelectronic device (1) of the LED (Light Emitting Diode) type, comprising at least two emitters (20, 21, 22) , which the at least two emitters (20, 21, 22) are contained within an outer transparent envelope (12) , so as to allow the passage of the light generated (A, B, C) by said at least two emitters (20, 21, 22) , characterized in that

each emitter (20, 21, 22) is configured in such a way as to emit a source (A, B, C) of white light of variable intensity, each at a different colour temperature .

2. Device according to claim 1, wherein three emitters (20, 21, 22) are provided, each emitter (20, 21, 22) being configured to emit a source (A, B, C) of white light of variable intensity, each at a different colour temperature .

3. Device according to claim 2, wherein a first emitter (20) emits light (A) at the temperature comprised between 5000 and 6000 K, a second emitter (21) emits light (B) at the temperature between 2400 and 3000 K, a third emitter (22) emits light (C) at the temperature between 2000 and 2400 K.

4. Device according to one or more of the preceding claims, wherein said outer envelope (12) is constituted at least in part by transparent glossy material .

5. Device according to one or more of the preceding claims, wherein said outer envelope (12) comprises a lens (13) arranged perpendicular to the light beam (A, B, C) emitted by said emitters (20, 21, 22) , which lens (13) has a surface with a concavity facing towards the emitters (20, 21, 22) , so as to make the light visible from multiple points of view, maintaining the chromatic separation of the light sources generated by the said emitters (20, 21, 22) .

6. Device according to claim 5, wherein said lens (13) is made of transparent glossy material.

7. Device according to one or more of the preceding claims, wherein said outer envelope (12) has a section of less than 14 square millimetres.

8. Device according to one or more of the preceding claims, wherein the generated light consists of a mixing of the light sources emitted by at least two of said three emitters (20, 21, 22) .

9. Method for generating a light source capable of recreating a metallic appearance colour, which method provides for the use of the device according to one or more of the preceding claims from 1 to 8,

characterized in that

the generation of said light source provides the simultaneous activation of at least two of said emitters,

the light sources of each emitter being filtered by an outer envelope of transparent glossy material, in order to recreate the chromatic mutability feature based on the position of an observer.

9. Method according to claim 8, wherein each emitter emits white light at a different temperature.

10. Method according to claim 8 or claim 9, wherein the generation of said light source is obtained by mixing the light sources emitted by said three emitters, according to predetermined percentages based on the metallic effect to be recreated.