Patent Application
20210003275
This application claims the benefit of EP Patent Application No. 19184331.7, filed Jul. 4, 2019, which is incorporated by reference as if fully set forth.
The present invention relates to a lighting device, in particular for automotive lighting applications and more particular in the form of a luminous band or lighting ribbon.
In the automotive field, it is currently a trend to implement lighting devices which can be controlled dynamically. This means that it is no longer sufficient that the lighting device can be switched on and off, but that in addition parts of the lighting device must be individually adjustable. For instance, in order to generate a dynamic lighting effect, individual parts may be switched on and off or may be dimmed. The availability of light emitting semiconductors (LEDs) has considerably enhanced the development of light emitting device that may be controlled dynamically.
LEDs may be controlled individually by addressing each LED by separate electronic wires. However, this results in numerous wires that need to be connected to a lighting driver in order to control each light emitting diode (LED) individually. This increases the necessary effort to fabricate and implement such a lighting device. Further, due to the numerous wires and the complex wire routing, the spatial constraints of the lighting device, in particular for automotive lighting applications, are easily exceeded.
In order to avoid complex wire routing within the lighting device, it is possible to use flat ribbon cables instead. However, by using such flat ribbon cables, the flexibility of the lighting device is limited since flat ribbon cables are flexible in one direction only and not flexible and bendable in a plane in which the wires of the flat ribbon cable are arranged. Often, modern automotive lighting devices need to follow a complex three-dimensional (3D) shape. Therefore, flat ribbon cables are not suitable for 3D applications.
Alternatively, it is well-known to combine each LED with a control chip such as integrated circuit (IC) or microprocessor, wherein the control chips of the whole lighting device are communicating via a bus wire. However, implementing a control chip for each LED increases the costs of the lighting device. This is in particular true for the automotive field in which each IC or microprocessor must be tested and certified. This decreases the applicability of this solution and prolongs necessary development and design periods. Further, error detection is typically required in the automotive field and needs to be implemented by additional circuitry, which increases the complexity even further.
US 2018/078072 A1 describes a light string with parallel circuits driven respectively by three independent command signals that merge at a common return path. Each of the circuits may have a unique color scheme and/or spatial distribution, for example, to provide for lighting effects. One or more of the lighting elements in any of the circuits may be individually addressable by, for example, serial commands supplied on the corresponding command signals.
US 2011/050109 A1 relates to a reverse polarity series type LED which is formed by two sets of LED and diode assemblies in reverse polarity series connection wherein the first set is consisted of at least one or multiple homopolar series or parallel connected or series and parallel connected LED's, and the second set consisting of at least one or more homopolar parallel or series connected or series and parallel connected LED's for further connection to the drive circuit formed by currentlimiting impedance and/or power storage and discharging devices and/or voltage-limit circuit devices in order to produce the required operational characteristics.
It is an object of the present invention to provide a lighting device that is flexible, dynamic controllable, less complex and suitable for error detection. The given object is achieved by a lighting device in accordance with claim 1 as well as a lighting device in accordance with claim 17. Further advantageous embodiments to the lighting device of the present invention have been specified in dependent claims.
According to a first aspect of the present invention, there is provided a lighting device, which is particularly suitable for automotive lighting applications, in particular in cars. According to claim 1, a plurality of lighting elements is arranged in a row, wherein each lighting element comprises at least one LED. Consequently, a luminous band or lighting ribbon is formed, which can be placed, for instance, below or between other lighting devices of a car and is convenient for the styling of signalling functions.
In addition, a long and very narrow lighting device may be achieved by arranging a large number of the lighting elements in a row. The lighting device has a length which extends the width of the lighting device. For instance, the length of the lighting device may be more than 200 mm or more than 500 mm, while for instance, the width of the lighting element may be below 10 mm or below 6 mm. The lighting elements are also known as or referred to as interposers. Preferably, the lighting elements are built identically. The lighting elements may comprise a printed circuit board (PCB) carrying the LED. The LED can be mounted to the PCB either by direct attachment of the naked die or can be mounted as a surface mounted device (SMD), as a through hole technology (THT) component or any other type of component. A PCB may comprise one LED or more than one LED.
In accordance with the first aspect of the present invention, the above-mentioned plurality of lighting elements is further divided into a plurality of segments and the lighting elements within each segment are electrically connected in series. In addition, each segment may comprise the same or different number of lighting elements. It is further preferred that the physical connections between the lighting elements within each segment are physically arranged in series as well in order for convenient control and design of patterns of lighting and dimming. Segmentation of the lighting elements enables random resolution of the lighting and dimming of the luminous band depending on the length of each segment compared with that of the luminous band. Further, the complexity of the lighting device can be reduced while still providing a diverse range of lighting functions due to the individually controllable segments of lighting elements.
In accordance with the first aspect of the present invention, a first contacting element is placed at a first end of the above-mentioned row of lighting elements providing current for a first group of segments, wherein the first group of segments comprises at least one segment of lighting elements. The first end may be either of the two ends of the luminous band. Following the luminous band design, electrical connections between the first contacting element and the first group of segments are physically arranged substantially in parallel to or along the row of lighting elements. Therefore, for a certain group of segments, only one contacting element is needed for power supply thus reducing the required number of contacting elements and this contacting element controls the lighting and dimming of this group independently to the other groups.
In addition, a contacting element serves to connect the lighting device to a lighting driver, wherein the contacting element can be built as an integral part of the lighting device or a separate entity. More specifically, the current can be provided via wires directly to the leadframe, for instance, by means of soldering structures comprised in the lighting elements (see, for instance,
Thus one or more contacting elements serve to control the lighting device and provide the power for the lighting device as well. In order to achieve dynamical lighting, the one or more contacting elements can address individual segments of lighting elements.
Therefore, the present invention has the advantage of independent, flexible and dynamic control of the lighting and dimming of lighting elements with random resolution as well as reduced complexity and space of the luminous band.
In particular, each segment is further divided into at least two sub-segments; and, within each segment, any two consecutive sub-segments are electrically connected anti series to each other, wherein anti series refers to that the two sub-segments are connected in series but with polarities of their respective lighting elements reversed to each other. Therefore, each sub-segment is only switched on during a certain period of the time before the respective current of each sub-segment is reversed; and the current running through the LEDs of each sub-segment is higher than the average current since not all the sub-segments are used at a given moment. The segment-wise resolution of the lighting and dimming is consequently increased; that is, within each segment, it can be flexibly selected which sub-segments are switched on during a given period. Further, the increment in resolution of lighting and dimming can be flexibly controlled by altering the amount of lighting elements in each sub-segment as well as that in each segment.
In particular, each LED is electrically connected anti parallel to at least one rectifier diode, wherein anti parallel refers to that each LED and the respective at least one rectifier diode are connected in parallel but with their polarities reversed to each other. Thus, currents at a given moment on un-used sub-segments are bypassed through the at least one rectifier diode arranged in the un-used sub-segments.
In particular, the first contacting element comprises a plurality of pins which refer to power-supply terminals. The pins are preferably arranged in one column and comprise at least one voltage supplying pin as well as at least one ground pin. The voltage supplying pin provides high voltage or low voltage, wherein high voltage supplying pins are also known as or referred to as anode pins or positive pins and low voltage supplying pins are also known as or referred to as cathode pins or negative pins.
In particular, a second contacting element is arranged preferably at a second end of the row of lighting elements providing current for at least a second group of segments, the second group of segments comprising at least one of the segments other than those in the first group. The second end is preferably different from and opposite of the first end as mentioned above. The second contacting element increases the number of addressable groups without increasing the complexity of the wire routing such that a large number of groups can be individually addressed by at least two contacting elements in order to provide dynamic lighting.
In particular, the electrical connections between the second contacting element and the second group of segments are physically arranged substantially in parallel to or along the row of lighting elements. The physical parallelism between the second contacting element and the second group of segments as well as that between the first contacting element and the first group of segments enhance the operability of independent and dynamic control.
In particular, the second contacting element comprises a plurality of pins, the pins being preferably arranged in one column and the number of pins being preferably the same as the number of pins of the first contacting element. It is possible that the second contacting element only comprises anode pins. Alternatively, it is possible that the second contacting element also comprises one or more anode pins and one ground pin. Alternatively, it is possible that the second contacting element comprises more than one ground pins.
In particular, at least one more contacting element is arranged between the first contacting element and the second contacting element along the row of lighting elements. Each of the at least one more contacting element provides current for one group of segments which is not supplied with power by the first contacting element or the second contacting element. The at least one more contacting element increases the number of addressable groups without increasing the complexity of the wire routing such that even more groups can be individually addressed for dynamic lighting.
In particular, the electrical connections between the at least one more contacting element and the respective group of segments are arranged substantially in parallel to or along the row of lighting elements. The physical parallelism between the contacting elements and their respective groups of segments enhances the operability of independent and dynamic control.
In particular, each contacting element between the first contacting element and the second contacting element comprises a plurality of pins, the pins being preferably arranged in two columns and the number of pins in each column being preferably the same as the number of pins of the first contacting element and/or the second contacting element. It is possible that each contacting element between the first contacting element and the second contacting element comprises one or more anode pins.
In particular, the lighting device in accordance with the present invention comprises 1, 2, or 3 contacting elements. With not more than 3 contacting elements, independent, flexible and dynamic control of the lighting and dimming patterns is possible without resorting to the complex solution provided by the microcontroller or occupying much space in the narrow luminous band.
In particular, the row of lighting elements is run through by a plurality of bendable electrical wires which are arranged substantially in parallel to each other. The electrical connections in the lighting device can thus be routed within the bendable electrical wires. The individual lighting elements are connected by the plurality of electric wires. The direct connection between subsequent lighting elements may as well comprise one or more physical connections, which physical connections serve to connect the lighting elements in the structure of the lighting device. Such physical connections may again be wires, more particularly also one or more of the electric wires may provide the physical connections and thus have a double function. Consequently, the lighting elements are connected by more than one electrical wire and may as well, in addition, be physically connected. If the lighting element is built as circuit board then the wires may be physically connected to the PCB or through the PCB and are in electrical contact with the one or more LEDs of the specific lighting element.
In particular, the bendable electrical wires are flexible in two axes. For instance, bending of the lighting device along horizontal and vertical axes in a certain surface of a car is possible. Versatile ways of styling of the signalling functions can thus fit into the signalling system of a car. Preferably, the wires are arranged in a common plane. Bending of the lighting device perpendicular to this plane is possible in order to adapt the shape of the lighting device to the specific application. Even a complex 3D shape is possible. Preferably the two bendable axes are perpendicular to each other and perpendicular to the longitudinal axis of the lighting device. The longitudinal axis of the lighting device is defined as the axis running along the row or lighting elements. A possible bending radius is preferably below 100 mm, more preferably below 50 mm and most preferably below 25 mm. Additionally or alternatively, the lighting device is twistable around the longitudinal axis. Preferably, twisting of the lighting device of 90° is possible within a length of 100 mm, more preferably within 75 mm and most preferably within 50 mm. With such flexibility the lighting device is suitable for a large number of applications and may be adapted to all kind of shapes.
In particular, the number of bendable electrical wires is the same as the number of pins of the first contacting element and/or the second contacting element and/or a third contacting element if any. Preferably, the arrangement of the wires between each of the lighting elements are identical along the complete row.
In particular, the lighting device in accordance with the present invention comprises 3 or 4 bendable electrical wires. Preferably the number of wires between each of the lighting elements is the same along the complete lighting device.
Increasing the number of wires between each of the lighting elements also increases the ability to control more groups of lighting elements. Simultaneously, the complexity of the lighting devices increases as well as the necessary installation space. Thus, with a maximum of 4 wires between each of the lighting elements, a sufficiently large number of groups can be controlled in order to provide dynamic lighting.
In particular, at least two segments consist of the same number of lighting elements. This makes it possible, for instance, for the lighting driver, to compare current and/or voltage of the two segments and to detect an error if there is a deviation of current or power between the two identical segments. Preferably each segment consists of the same number of lighting elements, and even more preferred each segment of lighting elements comprises the same number of LEDs. Thus, current and voltage of each segment can be compared with each other in order to obtain a reliable error detection.
According to a second aspect of the present invention, there is provided a lighting device, which is particularly suitable for automotive lighting applications, in particular in cars. In order for simplicity, similar features which pertain to the present invention as mentioned above regarding the first aspect of the present invention are omitted in the following. According to the present invention, a plurality of lighting elements is arranged in one or more parallel rows, wherein each lighting element comprises at least one LED. Each parallel row as mentioned above may comprise the same or different number of lighting elements. In this case, a luminous band or lighting ribbon comprising one or more rows of lighting sources is formed, which can not only be placed flexibly at positions where space is limited but also allows even more versatile patterns of lighting and dimming required by different signalling functions.
The plurality of lighting elements is divided into a plurality of segments and the lighting elements within each segment are electrically connected in parallel. In addition, each segment as mentioned above may comprise the same or different number of lighting elements; and lighting elements that belong to the same segment are preferably arranged in the same row of lighting elements. It is further preferred that the physical connections between the lighting elements within each segment are physically arranged in parallel as well in order for convenient control and design of patterns of lighting and dimming. Analogous to what is disclosed above, segmentation of the lighting elements enables random resolution of the lighting and dimming of the luminous band depending on the length of each segment compared with that of the luminous band; and the complexity of the lighting device is reduced while still providing a diverse range of lighting functions due to the individually controllable segments of lighting elements. Furthermore, the parallelism as mentioned here, in addition to the serialism as described before, between lighting elements in one segment, provides an alternative solution to the dynamic control mechanism.
In accordance with the present invention, current for the plurality of lighting elements is provided by a first contacting element comprising at least three power-supply pins. The first contacting element is arranged at one end of the one or more parallel rows of lighting elements and electrically connected thereto, wherein electrical connections therebetween are physically arranged substantially in parallel to the one or more rows of lighting elements such that a luminous band is formed. It is thus flexible to assign, from the at least three power-supply pins, two pins as power supply for certain segments of lighting elements such that different segments can be independently controlled by the respective power-supply pins connected thereto. The complexity is also reduced since one contacting element can flexibly control all the segments.
Therefore, analogously to what is discussed before, the present invention has the advantage of independent, flexible and dynamic control of the lighting and dimming of segments of lighting elements with random resolution as well as reduced complexity and space of the luminous band.
Further, while independent and dynamic control of the lighting elements, as discussed above, results from further grouping of segments and then assigning to different contacting elements different groups, the same effect is achieved now by segmentation of lighting elements across one or more rows and assigning the segments to different pairs of pins comprised in only one contacting element.
In particular, across any two power-supply pins, there are at least two segments electrically connected thereto which are connected anti parallel to each other. In other words, the at least two segments are connected in parallel but with polarities of their respective lighting elements reversed to each other. It can thus be flexibly selected, given any two power-supply pins, which segments therein are switched on during a given period. Alternatively, the length of each segment across any two power-supply pins can be extended by adding more lighting elements. Any two consecutive segments across any two power-supply pins may comprise the same number or different number of lighting elements depending on the requirements of the styling functions of the lighting applications. Considering the one or more rows, even more patterns can be achieved. As a result, the resolution, across any two power-supply pins, of lighting and dimming is further increased, as well as patterns of lighting functions formed along the whole luminous band.
Further, as mentioned above, the further increment of resolution as explained before, is achieved by adding a rectifier diode to each lighting element and sub-segmentation of a segment wherein any two consecutive subsegments are electrically connected anti series to each other such that only one sub-segment therein can be switched on at a given moment; whereas the same or similar effect is achieved now by an alternative solution wherein two consecutive segments across two power-supply pins are electrically connected anti parallel to each other such that, given certain values of the pair of pins, only one segment can be switched on.
In particular, the three power-supply pins comprised in the first contacting element are preferably arranged in one column, and values of voltages provided by the three pins are preferably different from each other. This configuration of power-supply pins serves to ensure, between any two power-supply pins, that some segments connected therebetween can be switched on while the other segments also connected therebetween but with reversed polarities cannot be switched on.
In particular, each lighting element is electrically connected to a current limiter in series. Current limiters, as is well known to be in the form of resistors, are used to ensure that there is not enough power to switch on, across any two given power-supply pins, segments whose polarities are reversed to those segments which can be switched on. Given a first power-supply pin, a second power-supply pin and a third power-supply pin with their values of currents in a decreasing order, it is possible that the first segment between the first power-supply pin and the second power-supply pin is connected therebetween with a current limiter connected between the cathode pin of the first segment and the second power-supply pin, and the second segment is connected anti parallel to the first segment as described above with a current limiter connected between the anode pin of the second segment and the second power-supply pin; alternatively or additionally, it is possible that the first segment between the second power-supply pin and the third power-supply pin is connected therebetween with a current limiter connected between the cathode pin of the second segment and the third power-supply pin, and the second segment is connected anti parallel to the first segment as described above with a current limiter connected between the anode pin of the second segment and the third power-supply pin; and alternatively or additionally, it is possible that the first segment between the third power-supply pin and the first power-supply pin is connected therebetween with a current limiter connected between the anode pin of the first segment and the first power-supply pin, and the second segment is connected anti parallel to the first segment as described above with a current limiter connected between the cathode pin of the second segment and the first power-supply pin. It is therefore possible to achieve, across any row of the luminous band as well as any two power-supply pins, flexible and dynamic patterns of lighting and dimming with selected voltages provided by the respective pins connected to the lighting driver. Thus, highly complex patterns or ways of lighting and dimming of different or distant lighting elements are possible with the present invention.
In particular, the lighting driver providing power through the power-supply pins is an active B6 bridge.
In particular and analogous to the first aspect of the present invention, the lighting device further comprises a plurality of bendable electrical wires running through the rows of lighting elements and arranged substantially in parallel to each other.
In particular and analogous to the first aspect of the present invention, the bendable electrical wires are flexible in two axes and/or twistable along a longitudinal axis of the lighting device, wherein preferably the two bendable axes are perpendicular to each other and/or perpendicular to the longitudinal axis.
In particular, the number of bendable electrical wires is preferably 3. Since three power-supply pins are provided, three electrical wires are enough to apply independent control over different rows along the luminous band as well as over different segments across any two power-supply pins, which greatly reduces the complexity and space required by a diverse range of lighting applications as well as ensuring versatile and complex patterns of lighting functions.
In particular, the present invention further comprises one or more of the features described in connection with the first aspect.
Non-limiting and non-exhaustive embodiments of the present invention as described above are referenced to the following figures, wherein same or similar elements are indicated by identical reference signs.
In the following description, for purposes of explanation rather than limitation, specific details are set forth such as the particular architecture, interfaces, techniques, etc., in order to provide a thorough understanding of the concepts of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments, which depart from these specific details. In like manner, the text of this description is directed to the example embodiments as illustrated in the Figures and is not intended to limit the claimed invention beyond the limits expressly included in the claims. For purposes of simplicity and clarity, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary details. The following description should not be understood to limit the assignment of any specific feature to a specific embodiment. Thus, the features of the embodiments mentioned hereinafter can be freely combined with each other.
All LEDs 14 are directed in the same direction. Thus, along the complete lighting device light is emitted only in one half space. Therein, the lighting device may emit light only with an opening angle of the emission equal to or below 180° and more preferably equal to or below 120° or equal to or below 90°. In order to enhance the characteristics of emission further, a reflective element can be arranged on a plane parallel to the common plane of LEDs (corresponding to the image plane of
The lighting elements 10 are arranged in a row, wherein each lighting element 10 is directly connected to a preceding lighting element and/or a following lighting element 10 by wires 16a, 16b and 16c. Thus, the lighting device of
A first connector or contacting element 18 arranged at a first end, namely the leftmost end, of the row of lighting elements 10 is connected via wires 16a to 16c to the row of lighting elements 10. Additionally, a second connector 20 is arranged at a second end, namely the rightmost end, of the row of lighting elements 10 and connected to the row of lighting elements 10 also by the wires 16a to 16c. The first connector and the second connector each comprise three pins 22, wherein the number of pins of the connectors 18, 20 is equal to the number of wires of the lighting device. Thus, by using two connectors 18, 20 and three wires 16a to 16c, five segments 12 can be individually controlled by a lighting driver (not shown) to which the lighting device of
As shown in
The first connector 18 comprises a ground pin 24, as well as a first anode pin 26 and a second anode pin 28. The second connector 20 comprises a third anode pin 30, a fourth anode pin 32 and a fifth anode pin 34. Therein, with the first anode pin 26, a first segment 12a of LEDs 14 is controlled, wherein the first segment 12a is connected to the ground pin 24 of the first connector 18 as well. With each further anode pin of the first connector 18 or the second connector 20, the segments 12 of LEDs 14 can be directly addressed by the lighting driver connected via the first connector 18 and the second connector 20 to the lighting device. Thus, the first connector 18 controls a first group of segments including 12a and 12b and the second connector 20 controls a second group of segments including 12c, 12d and 12e. The five segments 12 of LEDs 14 can be individually addressed in order to provide dynamical lighting, which is achieved only by using three parallel wires along the entire length of the lighting device, thereby maintaining the ability to bend the lighting device in all directions and providing a low complexity of wire routing within the lighting device.
The first connector 18 comprises a first ground pin, as well as a second ground pin and a first anode pin, as well as a second anode pin. The second connector 20 comprises a third ground pin and a fourth ground pin, as well a third anode pin and a fourth anode pin. Further, the first connector 18 controls a first group of segments including 12a, 12b and 12c and the second connector 20 controls a second group of segments including 12d, 12e and 12f and 12g. The first connector 18 and the second connector 20 are connected to the lighting elements 10 of the lighting device by four wires which are arranged in parallel along the entire length of the lighting device. Thus, by the pins of the first connector 18 and the second connector 20 connecting the lighting device to a lighting driver, each segment 12 can be controlled individually in order to provide dynamical lighting.
The lighting device of
In the example of
In the example of
As illustrated in the upper portion of
| Number | Date | Country | Kind |
|---|---|---|---|
| 19184331.7 | Jul 2019 | EP | regional |
