DE102010043296B4 - Light emitter module with deflecting optics - Google Patents

Abstract

Light emitter module, comprising: an LED (5) and a sensor (2), the LED (5) and the sensor (2) being connected via a control unit, as well as a light guide (5) which can be inserted into the module and is opposite the LED (5). 4A-D), and an optic (3A-D), the optic (3A-D) part of the light beams (6a-8a) of the LED (5) before they enter the light guide (4a-D) in the direction of the Sensors (2) branches off so that they can be detected by the sensor (2), the LED (5) and the sensor (2) being fixed on a common base (1), in particular a circuit board, characterized in that the LED (5) an RGB-LED is provided with several color diodes, in particular a green, a blue and a red color diode (6-8).

Description

Technical area

The present invention relates to interior lighting, in particular by means of LEDs, such as is used, for example, in automobiles. Such lighting can be so-called ambient lighting or effect lighting, but also signal lighting (for example in the event of danger).

State of the art

In the area of ambient lighting for vehicles, there is a desire for multicolor in addition to the familiar monochrome lighting. In-house, it is known to implement such a multicolor with several single-colored LEDs. However, the available installation space is small, which is why the light guide coupled to the LEDs should not exceed a certain diameter. Since the light guide should continue to be guaranteed homogeneously over great lengths, a maximum light guide diameter of 5.5 mm is usually assumed. With such a diameter, however, light can be coupled in using a maximum of two single-color LEDs.

By mixing the intensity of these two LEDs, in addition to a specific color of an LED, additional mixed colors can be generated, which in the CIE standard table are on straight lines connecting the pure colors.

In order to further increase the variety of colors in the vehicle, and even to be able to provide an unlimited number of colors, it would be advantageous to couple light using an RGB LED instead of several single-color LEDs. When using such an RGB LED, light guides with a diameter of 3.5 mm could also be used.

A color sensor could be used to control the RGB-LED. However, the problem arises that the light emitted by the RGB-LED must first be sufficiently mixed before it reaches the color sensor. Direct radiation into the color sensor is not possible because the intensity and color location information is falsified. Accordingly, the light guide would have to be adapted, which is time-consuming and causes increased costs.

The document DE 10 2006 099 551 B4 known, which relates to a device for generating light of a freely selectable color with a plurality of monochrome illuminants. A controller is designed here as a microprocessor and is connected by means of a line to a temperature sensor for detecting the temperature of the light-emitting diodes. Likewise, the control is connected by means of a line to a photodiode which is arranged facing a light exit surface of a prism, the light entry surface of which faces the photodiodes.

Another prior art is the document DE 10 2008 039 364 A1 known relating to a semiconductor lighting device. The semiconductor light source can comprise at least one LED. Furthermore, several light-emitting diodes of the same color and / or different colors can be present.

Another prior art that DE 10 2008 025 865 A1 , relates to a method for operating an LED module consisting of a number of different colored LEDs. The problem arises from this state of the art that, in the case of a new RGB-RGBA or hybrid LED module, only the reproducibility of defined LED light will enable the use of LED technology in general lighting. Only a color sensor that determines the color location and can therefore calculate the individual color components allows precise color location control.

The pamphlets DE 199 52 795 A1 and DE 196 03 025 A1 disclose a light emitting module according to the preamble of claim 1.

Subject of the invention

The object of the present invention is to provide a module with an LED and a sensor in which the components can be accommodated in a small installation space and at the same time the light emitted by the LED is hardly attenuated by the measurement with the sensor.

To achieve this object according to the invention, a module according to claim 1 is provided. Exemplary embodiments of the invention can be found in the dependent claims.

The core idea of the present invention is to arrange the LED (preferably an RGB LED), the sensor and the optics in a module in such a way that before the light from the LED is coupled into a light guide inserted into the module, a small portion of this light is guided to the sensor becomes. The sensor and the control unit are calibrated for this configuration, and the control unit regulates the LED based on the measurement results.

Therefore, the sensor only needs to be calibrated / tuned once for a specific module. The regulation is therefore independent of the changing geometry of the light guide. Incidentally, the regulation can not only be used for color matching, but can also be used for brightness control. Furthermore, the present invention enables the individual elements to be accommodated in a small installation space, and it is also prevented that the light emitted by the LED is negatively influenced by the measurement.

The LED and the sensor are fixed on a common base. This ensures that the sensor is aligned relative to the LED. In particular, a printed circuit board (PCB) is used as the common basis.

The LED is a so-called RGB LED with several color diodes. An RGB LED is usually equipped with a green, a blue and a red color diode. A wide range of colors can be realized by mixing the individual colors.

It is further preferred that the sensor is calibrated when it is installed in the light emitter module with respect to the LED that is also already installed in the light emitter module. The sensor can thus be adjusted to the conditions in the specific module. This is particularly advantageous if - in the case of an RGB LED - different color components are detected by the sensor depending on the light emitter module.

Thus, the control unit connected to the LED and the sensor can control the LED in a targeted manner on the basis of the measurement data of the sensor, and thus set the desired color exactly. In a further preferred embodiment, it is preferred that the light guide used has a diameter between 2-5 mm, preferably about 3.5 mm. The dimension of about 3.5 mm in diameter is a commonly used size. This ensures that the light guide is homogeneous over relatively long distances, which can lead to problems with larger light guide diameters.

In a further embodiment, it is preferred that the light beams that have entered the optics are reflected at at least one interface within the optics. This results in a thorough mixing of the light until it reaches the sensor.

In a further embodiment, the sensor is provided in such a way that a detection surface points in the direction of the light exit from the LED. This enables an extremely compact design to be implemented.

In a further particular embodiment, it is provided that the light guide has a conical end section in an end area which is opposite the LED. This conical end section is laterally enclosed by the optics. The conical end section thus offers the area in which the light is coupled into the light guide. The optics surround this area and can pick up light that is not coupled into the conical end section and guide it to the sensor.

It is preferably provided that the end face of the conical end section of the light guide facing the LED has a smaller area than the light exit opening of the LED. This end face of the conical end section is only slightly smaller than the area of the light exit opening, so that only a very small part of the light from the LED does not enter the light guide but into the optics.

Furthermore, it is preferably provided that the conical end section of the light guide has a step at the transition to the cylindrical light guide. The optics can rest on this step and the light guide, the optics and the LED can thus be positioned in relation to one another.

In another preferred embodiment, separate optics are provided in sections between the light guide and the LED. In this configuration, the light thus enters the optics from the LED and a small part of the light is reflected at the interface between the optics and the light guide in the direction of the sensor. The remaining major part of the light is transmitted to the light guide.

For this purpose, it is preferably provided that the interface between the optics and the light guide is cloudy or has a clear but defined reflective coating. This parameter is used to set how much of the light is transmitted to the light guide and how much is reflected to the sensor.

Figure list

• 1 shows an exemplary embodiment of the present invention in which an RGB-LED, a light guide, an optical system and a color sensor are arranged in a compact structure.
• 2 Figure 12 shows a schematic view of a second embodiment of the present invention in which a portion of optics is located between an LED and a light guide.
• 3 Figure 3 shows a third embodiment of the present invention
• 4th Fig. 10 shows a fourth embodiment of the present invention which uses optics similar to the third embodiment.

Detailed description of the exemplary embodiment

1 shows a schematic representation of an exemplary embodiment of a module with an RGB LED 5 and a color sensor 2 . In this context, RGB-LED means an LED (light emitter diode) with several diodes. This term also includes RGGBs, RGBWs or similar LEDs with more than one light-emitting chip.

Here, the RGB LEDs are in a housing G 5 as well as the color sensor 2 on a circuit board 1 appropriate. The color sensor 2 can for example be a so-called truecolor sensor or an RGB sensor. In a vertical direction above the RGB LED 5 (that of the circuit board 1 facing away from the RGB-LED 5 ) there is a light guide inserted or plugged into the module 4A , which in this embodiment has a diameter of about 3.5 mm, and forwards the light beams emitted by the RGB-LED. At the one to the RGB-LED 5 On the facing side, the cylindrical light guide comprises a conical end, the cone having a flat tip in the direction of the RGB LED, and a step in the transition to the cylindrical light guide 4b is available. The level of the level 4b as well as the plane of the flat cone tip 4a are essentially parallel to each other.

The color sensor is also on the circuit board 2 appropriate. The detection section of the sensor 2 points in the same direction as the main light exit direction of the RGB-LED (in 1 pointing away from the circuit board in the vertical direction).

The module according to the present embodiment further comprises optics (RGB optics) with which light beams from the RGB-LED to the color sensor 2 can be guided by reflection. The optics 3 can also do this on the circuit board 1 and it extends from a portion of the RGB LED 5 to the color sensor 2 .

The RGB LED 5 comprises several color diodes, in the present embodiment one diode for green light 6th , a diode for blue light 7th and a diode for red light 8th . With the help of these diodes 6-8 a large color spectrum can be generated.

It is provided here in the construction of the module according to the invention that a large part of the from the RGB-LED 5 emitted color rays on the surface 4a into the light guide 4A reached (approx. 99%). The scattered radiation of the RGB-LED is in the edge area next to the conical end of the light guide 4A due to the optics that are arranged complementarily around this area and laterally enclose the cone of the light guide 3 collected, and guided to the sensor by reflection within the optics. Here, the light from the individual diodes is not collected in equal proportions due to their position in relation to the optics and the sensor. However, by calibrating the system it can be ensured that the sensor can evaluate the values from the optics in such a way that the desired color is fed into the light guide by means of a corresponding color setting.

The arrangement according to the preferred embodiment thus guarantees indirect radiation into the color sensor. In addition, the light emitted by the LED is hardly attenuated.

2 Figure 3 shows a second embodiment of the present invention. As in the first embodiment, this variant comprises a printed circuit board in a housing G 1 , a sensor mounted on it 2 , an RGB LED 5 with diodes 6th , 7th and 8th as well as a light guide arranged vertically above the RGB-LED 4B . This light guide 4B was inserted into the module as in the first embodiment and releasably attached to it. The relative alignment of the components mentioned to one another is essentially the same as in the first embodiment. However, the light guide has 4B does not open the conical termination described in the first embodiment, but closes with a to the circuit board 1 and thus to the top of the RGB LED 5 essentially plane-parallel surface 4c from.

In the area of the conical end of the light guide 4A of the first embodiment is the optics in the second embodiment 3B available. In other words, the look is 3B not interrupted by the conical termination of the light guide, as in the first embodiment.

The optics 3B the second embodiment transmits almost all of the light (approximately 99%) coming from the LED 5 is emitted into the light guide 4B . A small proportion is at the interface of the optics 3B to the light guide 4B reflected, scattered and directed towards the sensor. This is where the optics 3B opaque or clear but defined reflective coating at this boundary surface, so that the scattered light portion is increased somewhat. The turbidity also ensures that all the colors emitted by the various diodes are mixed.

As in the first embodiment, there is thus indirect irradiation from the RGB LED 5 emitted rays into the sensor 2 guaranteed. In addition, there is good mixing of the individual diodes 6-8 emitted light.

3 Figure 3 shows a third embodiment of the present invention. Here is the same as in the embodiments 1 and 2 , a circuit board 1 , a sensor attached to it 2 as well as an RGB LED 5 provided in a housing G. Vertically above the RGB LED 5 there is a light guide 4C , however, unlike the embodiments 1 and 2 , a beveled surface 4d towards the RGB LED 5 having.

Between the RGB LED 5 as well as the beveled surface 4d of the light guide 4C is an optic 3C provided, which is designed in the manner of a prism. These optics transmit a large part of the light emitted by the RGB LED into the light guide 4C . A small proportion is at the interface between the optics 3C and the light guide 4C (first reflective surface) reflected, and a second reflective surface of the optics 3C diverted directly into the sensor detector surface. The first reflection surface could be provided with a special filter layer that reflects a certain, very small portion of the light and allows the rest of the light rays to pass through.

The in 3 The structure shown has the advantage that fewer tolerance problems occur when the module is installed, since the light beams are always deflected at the same angle and the distance between the RGB LED and the sensor always remains the same. Accordingly, larger tolerance ranges can be used during assembly. In order to further improve the quality of the measurement results, a roughening of the second reflection surface of the optics could, for example 3C , or the exit surface of the optics 3C towards the sensor 2 be provided.

4th Figure 12 shows a fourth embodiment of the present invention which is similar to the third embodiment. The main difference is that the color sensor 2 laterally next to the optics 3D is arranged, and the light rays 6a - 8a not directly on the detection section of the color sensor 2 hit. However, clouding of the second reflection surface would, as in the embodiment 3 that favor the mixing of the light rays. Incidentally, the surface facing the sensor is the optics 3D roughened so that the light is coupled out in the direction of the sensor 2 can take place.

The in 4th The construction shown has the advantage that the detector surface is directed towards a mixed light and not the direct light of the RGB-LED 5 on the detection section of the color sensor 2 hits.

In the previous embodiments, there are various ways of using the color sensor 2 on the circuit board 1 to fix. One possibility is to have contact pins on the circuit board 1 and to provide guide slots in the housing G for the pins. A receptacle for the contact pins is provided at the individual outputs of the sensor. The mount between the springs on the color sensor 2 is smaller than the contact pin diameter so that the contact pin engages and thus a firm contact can be guaranteed.

Another possibility is to use the contact pins on the color sensor 2 to be provided. Contact is made with the circuit board via so-called mqs action pins. For this purpose, contact holes are made available on the circuit board that are smaller in diameter than the contact pins. When the contact pins are pressed into the bores, material in the bores is plastically deformed, and the contact pins thus lock firmly into place.

Claims (11)

Light emitter module, comprising: an LED (5) and a sensor (2), the LED (5) and the sensor (2) being connected via a control unit, as well as a light guide (5) which can be inserted into the module and is opposite the LED (5). 4A-D), and an optic (3A-D), the optic (3A-D) part of the light beams (6a-8a) of the LED (5) before they enter the light guide (4a-D) in the direction of the Sensors (2) branches off so that they can be detected by the sensor (2), the LED (5) and the sensor (2) being fixed on a common base (1), in particular a circuit board, characterized in that the LED (5) an RGB-LED is provided with several color diodes, in particular a green, a blue and a red color diode (6-8). Light emitter module according to one of the preceding claims, in which the sensor (2) is calibrated during assembly with respect to the LED (5) mounted in this light emitter module. Light emitter module according to one of the preceding claims, in which the control unit can control the LED (5) based on the measurement data from the sensor (2). Light emitter module according to one of the preceding claims, in which the light guide (4A-D) has a diameter of 2 to 5 mm, preferably approximately 3.5 mm. Light emitter module according to one of the preceding claims, in which the light beams (6a-8a) of the LED (5) which have entered the optics (3A-D) are reflected at interfaces within the optics (3A-D). Light emitter module according to one of the preceding claims, wherein the sensor (2) a Has detection surface which points in the emission direction of the LED (5). Light emitter module according to one of the preceding claims, in which a conical end section of the light guide (4A) lies opposite the LED (5), and the conical end section is laterally enclosed by the optics (3A). Light emitter module according to Claim 7 , in which the end face (4a) of the conical end section of the light guide (4A) facing the LED (5) has a smaller area than the light exit opening of the LED (5). Light emitter module according to Claim 7 or 8th , in which the conical end section forms a step at the transition to the light guide. Light emitter module according to one of the Claims 1 - 6th , in which the optic (3B-D) lies in sections between the light guide (4B-D) and the LED (5), and thus part of the light emitted by the LED (5) at the interface between the optic (3B-D ) and the light guide (4B-D) is reflected in the direction of the sensor (2). Light emitter module according to Claim 10 , characterized in that at least the interface between the optics (3B-D) and the light guide (4B-D) is cloudy or clear - but has a defined reflective coating.

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