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Title:
REGULATION OF SEQUENTIALLY OPERATING LIGHT SOURCE AND DEVICE FOR CARRYING OUT THE METHOD
Document Type and Number:
WIPO Patent Application WO/2018/029587
Kind Code:
A1
Abstract:
The present invention refers to a method and a device for sequentially operating light source, in particular a lighting system for signalizing a change of driving direction of a motor vehicle, comprising a plurality of light emitting diodes (LED) connected in series, said diodes can be activated in a pre-determined sequence within a required time frame t0. The method comprises activating within a required time frame (t0) a sequential operation of a plurality of LEDs, wherein the operation of the first LED in the plurality of LEDs and operation of the last LED in the plurality of LEDs is carried out within an actual time frame (t1) of operation. The method further comprises activating after lapse of a safety time frame (t2) of all LEDs (11, 12... 1n) simultaneously.

Inventors:
KRZIC, Peter (Kamnik pod Krimom 8, 1352 Preserje, 1352, SI)
PERKON, Martin (Trg prekomorskih brigad 6, 1000 Ljubljana, 1000, SI)
RAZPOTNIK, Jure (Tesovnikova ulica 45, 1000 Ljubljana, 1000, SI)
Application Number:
IB2017/054810
Publication Date:
February 15, 2018
Filing Date:
August 07, 2017
Export Citation:
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Assignee:
HELLA SATURNUS SLOVENIJA PROIZVODNJA SVETLOBNE OPREME ZA MOTORNA IN DRUGA VOZILA, D.O.O. (Letališka Cesta 17, 1000 Ljubljana, 1000, SI)
International Classes:
H05B33/08; B60Q1/38
Domestic Patent References:
WO2011148259A22011-12-01
Foreign References:
US20130127340A12013-05-23
FR2057350A51971-05-21
US20100128479A12010-05-27
US20040114384A12004-06-17
Attorney, Agent or Firm:
INVENTIO D.O.O. (Dolenjska cesta 11, 1000 Ljubljana, 1000, SI)
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Claims:
Claims

1. A method for sequentially operating light source on a vehicle, in particular a lighting system for signalizing a change of driving direction of a motor vehicle, comprising a plurality of light emitting diodes (LED) (li, I2 ... ln) connected in series, said diodes can be activated in a pre-determined sequence within a required time frame (to), characterized in that, it comprises the following steps:

a) activating within a required time frame (to) a sequential operation of a plurality of LEDs (li, I2 ... In), wherein the operation of the first LED (li) in the plurality of LEDs and operation of the last LED (ln) in the plurality of LEDs is carried out within an actual time frame (ti) of operation;

b) activating by means of a reserve security element (10) and after lapse of a safety time frame (t2) of all LEDs (li, I2 ... ln) simultaneously.

2. A method according to claim 1, characterized in that, the required time frame (to), the actual time frame (ti) and the safety time frame (t2) are equal.

3. A method according to claim 1, characterized in that, said actual time frame (ti) is at most equal or smaller than the required time frame (to).

4. A method according to claim 1, characterized in that, said safety time frame (t2) is equal or smaller than the required time frame (to), but larger from the actual time frame (ti) of the activation of all LEDs (li, I2 ... ln).

5. A device for carrying out a method according to claims 1 do 4, characterized in that, it comprises

a) a plurality of light emitting diodes (li, I2 ... ln) connected in series;

b) a feeding device which controls at least one LED from the plurality of LEDs (li, I2 c) a thermal protection element (4) the resistance thereof depends on temperature;

d) an excess voltage protection element (5);

e) a security element (6), which in case that at least one LED (11,1.2 ... In) from the plurality of LEDs fails provides for that a driver is alerted about the failer; f) a timer and shift element (7), which provides for a sequential activation of LEDs (li, g) a control element (8), which connects all aforementioned elements and provide for carrying out of respective functions thereof;

h) a reserve security element (10), which is associated with the control element (8) and takes care of the operation when the failure occurs and, respectively, when any of the components fails.

6. A device according to claim 5, characterized in that, the number n of LEDs is preferably selected as an even number.

Description:
REGULATION OF SEQUENTIALLY OPERATING LIGHT SOURCE AND DEVICE FOR

CARRYING OUT THE METHOD

[0001] The present invention refers to a method and a device for sequentially operating light source, in particular a lighting system for signalizing a change of driving direction of a motor vehicle, comprising a plurality of light emitting diodes connected in series, said diodes can be activated in a pre-determined sequence.

[0002] Light systems for signalizing driving direction of a motor vehicle, comprising a plurality of light emitting diodes (LED) connected in series, said diodes can be activated in a pre-determined sequence are well known from various patent applications such as DE 10 2015 010 315 Al, CN 104816668 A, US 2015/0158416 Al, US 2013/0127612 Al, US 2009/0051523 Al, JP 2005132256 A, for example. None of said documents, however, disclose how to operate a sequentially operating light in order to enable a reliable functional saf ety of the lighting system operation. In case of a sequential circuit failure only the first LED from the plurality of LEDs would be operational in the worst scenario, however, the failure would not be detected by a vehicle diagnostic which is absolutely unacceptable from the functional safety point of view. In order to remedy said problems, most of the known solutions focus either to duplicating the control circuit or to duplicating the light sources or to the combination thereof.

[0003] It is the object of the present invention to create a method of sequentially operating light source, particularly with a motor vehicle, which enables a reliable functional safety of a lighting system operation. The invention further refers to a device for carrying out said method.

[0004] The object as set above is solved, according to the present invention, by features according to the characterising clause of the claim 1. The invention is disclosed in detail in corresponding subclaims.

[0005] The invention is further described in detail by way of non-limiting embodiment, and with a reference to the accompanying drawing, which shows a schematic view of a device for enabling a functional safety according to the invention.

[0006] A detailed description of the invention is based on the embodiment representing a device for sequentially operating lighting system for signalizing a change of driving direction of a motor vehicle and, respectively, a so called direction indicator. Said direction indicator comprises a plurality of light emitting diodes li, I2 ... l n (LED) connected in series, that are controlled by means of a feeding device, such as a DC/DC converter or a plurality of constant current sources 2i, 22 ... 2 m , as provided for in the present embodiment, and similar. The number n of LEDs is preferably, yet non-limiting, selected as an even number. When the number n of LEDs is selected as the even number, a single current source 2i, 22 ... 2 m is assigned per each pair li, I2; I3, I4 ... l n -i, In of the LEDs, whereby the direction indicator is attached by means of a connecting element in a manner know per se to the wiring of the headlamps. In the present embodiment, the number m of the current sources 2i, 22 ... 2 m preferably equals to n/2. Energy is fed to said direction indicator via an input protecting element 3, which protects direction indicator against possible polarity reversal, electrostatic impulse, voltage pulse, and similar.

[0007] Moreover, said circuit is provided with a thermal protection element 4, the resistance thereof varies in dependence of temperature. When the temperature on said circuit reaches a critical value, said thermal protection element 4 lowers the current fed. The luminosity decreases consequently, thus, keeping the electronic components in permitted temperature ranges.

[0008] Said circuit is further provided with an excess voltage protection element 5, which in case of excessive voltage, in the present embodiment the voltage >19V, switches off the entire circuit of the direction indicator. In addition, a security element 6 is provided on said circuit which, in case that at least one LED 11,1.2 ... l n from the plurality of LEDs fails, provides for that the diagnostic system in the vehicle alerts a driver about the failure.

[0009] In addition to said elements, said circuit of the direction indicator also comprises a timer and shift element 7, which takes care of the sequential lighting of LEDs l i, I2 ... l n , and a control element 8, which connects all aforesaid elements and takes care of the respective functions thereof are carried out. A switch 9i, 92 ... 9k is allocated to each second LED I2, I4 . . . ln-i from the plurality of LEDs li, I2 ... l n . The number k of switches 9i, 92 ... 9k preferably equals to the number m of the current sources 2i, 22 ... 2 m , which preferably equals to n/2. At the beginning of the operation, when the energy is fed to the direction indicator all switches 9 i, 92 ... 9k are closed, wherein only the first current source 2i is turned on activating thus the operation of the first LED li from the plurality of LEDs li, I2 ... l n . In the next sequence, the timer and shift element 7 opens the first switch 9i, whereby the second LED I2 is activated. Afterwards, the second current source i is turned on and the process repeats with the next pair of LEDs I3, I4 from the plurality of LEDs li, I2 ... l n .

[0010] It is provided for according to the present invention, that a reserve security element 10 is attached to the control element 8, which takes care of operating the direction indicator when an error occurs and, respectively, at the failure any of the components of the direction indicator. Sequentially operating lighting system for signalizing change of driving direction operates in a required time frame to, which typically amounts to less or equal to 200 ms. In said time frame to a required number of LEDs must be sequentially activated, preferably all LEDs l i, I 2 . . . In, from the first LED to the last one. After a lapse of a saf ety time frame t2, which is smaller or at most equal to said required time frame to, but larger from or at least equal to an actual time frame ti of lighting all LEDs li, I2 . . . l n from the plurality of LEDs, the reserve security element 10 provides for reactivating all LEDs l i, I2 . . . l n from the plurality of LEDs, but this time all simultaneously. Thus, the direction indicator according to the present invention operates in a manner, that the LEDs l i, I2 ... l n at first light sequentially, and within the safety time frame t2 also all simultaneously.

[0011] Said actual time frame ti of lighting all LEDs li, I2 . . . l n from the plurality of LEDs can be at most equal or smaller with respect to said required time frame to and is typically selected in the range between 130 ms and 150 ms. When simultaneously all LEDs l i, I2 . . . l n from the plurality of LEDs are activated, said safety time frame t2 is smaller or at most equal to said required time frame to, and simultaneously larger than or at least equal to said actual time frame ti of the lighting all LEDs l i, I2 . . . l n from the plurality of LEDs, wherein the safety time frame t2 is typically selected in the range between 150 ms and 190 ms.

[0012] When the direction indicator and, respectively, the device for providing functional safety according to the invention operates flawless, than the process of activating LEDs is carried out in the required sequential manner. If, however, any error occur on the circuit of the direction indicator and, respectively, any component of the direction indicator fails to operate, the process of activating LEDs is carried out in a manner, that at first LED l i is activated, and after a lapse of the safety time frame t2 all other LEDs are activated simultaneously. In the following, the invention is represented on the basis of two examples.

[0013] Example 1: Failure of the timer and shift element When the direction indicator is turned on the first LED li in the plurality of LEDs is always activated, whereas remaining LEDs I2, I3 ... In are not activated due to said non-operation of the timer and shift element 7. In this particular case, said reserve security element 10 provides for by means of overriding all other circuits and, components, that all LEDs are activated simultaneously within the safety time frame t2 < to oz. t2 > ti.

[0014] Example 2: Failure of one of the LEDs

If anyone of LED li, I2 ... l n from the plurality of LEDs fails, such as LED I3 for instance, thes ecurity element 6 stores the information about a limited failure of the LED I3 and all LED are not activated until the end of the sequence. The LEDs remain non-activated for the entire time frame within which the direction indicator is supposed to operate. The diagnostic takes place since the LEDs are not active and, thus, there is no power consumption and, respectively, the power consumption decreases.