DESC:FIELD
The present disclosure relates to the field of headlamp controls.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Derating is a technique usually employed in electrical power and electronic devices, wherein the devices are operated at less than their rated maximum power dissipation, taking into account the case/body temperature, the ambient temperature and the type of cooling mechanism used. Typically, derating of headlamps providing low beam, high beam, high beam booster and daytime running lamp (DRL) is done by reducing the current passing to the headlamp by reducing the temperature of the light emitted and the light output by 10%. While derating the headlamps, if the temperature exceeds beyond 120° Celsius, the lamp is turned off to protect the headlamps.
However, if the headlamps are not turned off in time, they could be damaged, since the lamps are configured to operate in derating mode even at design intended ambient of 70° Celsius. Usually, the heat is transferred from a heat sink, connected to the headlamp, to its surroundings, but not effectively.
Another problem that has been identified is that it is necessary to generate desired lumen up to 110° Celsius at a constant current supply. However, at cold start, the constant current supply is more than required which then leads to more brightness at start and faster heat up, and eventually damaging the headlamp.
There is therefore felt a need for a system for derating the headlamp that alleviates the aforementioned drawback.

OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
An object of the present disclosure is to provide a system for derating a headlamp.
Another object of the present disclosure is to provide a system for derating a headlamp at a predetermined temperature range beyond which the headlamp is prone to damage.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure envisages a system for derating a headlamp. The system comprises a temperature sensing unit, a control unit and an actuator. The temperature sensing unit is configured to sense the temperature of the headlamp to periodically generate a sensed temperature value. The control unit is configured to communicate with the temperature sensing unit to receive the sensed value. The control unit is configured to compare the sensed value with a predetermined threshold value to generate a compared signal. The actuator is configured to communicate with the control unit and the headlamp. The actuator is configured to receive the compared signal and switch off the headlamp based on the compared signal.
BRIEF DESCRIPTION OF DRAWINGS
A system, of the present disclosure, for derating a headlamp will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a schematic view of the system of the present disclosure; and
Figure 2 illustrates graphical representations of the performance of a headlamp having an anodized heat sink and thermal paste.
LIST OF REFERNCE NUMERALS
100 system
105 temperature sensor
110 control unit
112 repository
114 comparator
115 actuator
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms “a”, “an” and “the” may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms “comprises”, “comprising”, “including” and “having” are open-ended transitional phrases and therefore specify the presence of stated features, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, operations, elements, components, and/or groups thereof.
When an element is referred to as being “attached to”, “connected to” or “coupled to” another element, it may be directly on, engaged, connected or coupled to the other element.
Terms such as ‘between’ and the like, may be used in the present disclosure to describe relationships between different elements as depicted from the figures.
A system (100), of the present disclosure, for derating a headlamp will now be described in detail with respect to Figure 1 and Figure 2.
As shown in Figure 1, the system (100) comprises a temperature sensing unit (105), a control unit (110) and an actuator (115). The temperature sensing unit (105) is configured to sense the temperature of the headlamp to periodically generate a sensed temperature value. The control unit (110) is configured to communicate with the temperature sensing unit (105) to receive the sensed value. The control unit (110) is configured to compare the sensed value with a predetermined threshold value to generate a compared signal. The actuator (115) is configured to communicate with the control unit (110) and the headlamp. The actuator (115) is configured to receive the compared signal and switch off the headlamp based on the compared signal.
In an embodiment, the headlamp is an LED headlamp.
In an embodiment, the temperature sensing unit (105) is provided within the headlamp. More specifically, the temperature sensing unit (105) is located in the PCB of the LED, proximal to the LED soldering point.
In one embodiment, the temperature sensing unit (105) includes a temperature sensor for sensing the temperature of the headlamp to periodically generate a sensed temperature signal. The temperature sensing unit (105) further includes a converter communicating with temperature sensor. The converter is configured to receive the sensed temperature signal, and is further configured to convert the sensed temperature signal to the sensed temperature value.
In an embodiment, the control unit (110) includes a repository (112) configured to store the predetermined threshold value. The control unit (110) further includes a comparator (114). The comparator (114) is configured to communicate with the temperature sensing unit (105) to receive the sensed temperature value. The comparator (114) is further configured to communicate with the repository (112) to receive the predetermined threshold value. The comparator (114) is configured to compare the sensed temperature value with the predetermined threshold value to generate the compared signal when the sensed temperature value is greater than predetermined threshold value.
In an embodiment, the comparator (114) is configured to generate the compared signal when the sensed temperature value exceeds a predetermined threshold value of 110°C.
In one embodiment, the system (100) includes an anodized heat sink configured to facilitate mounting of the headlamp thereon. The heat sink is configured to absorb the heat dissipated by the printed circuit board of the headlamp preferably while the headlamp is in operation. In another embodiment, the heat sink includes a fan-and-motor assembly configured to enable air movement therewithin. The movement of air in the heat sink allows faster dissipation of heat released by the headlamp.
Anodizing the heat sink reduces the temperature on the printed circuit boards (PCBs) by approximately 6° Celsius.
In another embodiment, the system (100) includes thermal paste applied on the headlamp for dissipating heat released by the headlamp. The thermal paste improved the rate of heat transfer between the heat sink and the headlamp, especially when the headlamp is in operation. In an embodiment, the thermal paste has a thermal conductivity greater than 3.2W/m K. In another embodiment, the thermal paste has a thermal conductivity of 10W/m K.
The anodized heat sink and the thermal paste, both help in ensuring that the temperature of the headlamp does not exceed 110°C. However, in case the temperature rises to 120°C, the comparator (114) and the actuator (115) come in play to switch off the headlamp, thereby preventing any damage to the headlamp.
In an exemplary embodiment, a trial was conducted in a thermal chamber heated at 70°C for a headlamp provided with the system (100), the anodized heat sink and a thermal paste of 3.2W/m K. Figure 2 represents the graph showing the time required for the headlamp to achieve a temperature of 110°C. It was observed that the temperature never exceeded beyond 110°C, the system and hence never entered the derating mode. In fact, the temperature stayed at a temperature below 100°C.
A similar trial was conducted for a headlamp provided with the system (100), the anodized heat sink and a thermal paste of 10W/m K in the same thermal chamber. Figure 3 represents the graph showing the time required for the headlamp to achieve a temperature of 110°C. It was observed that the temperature, in this case, also never reached 110°C, and hence never entered the derating mode.
The system (100) thus ensures that the life of the headlamp is not affected as the temperature is kept below 110°C at all times.
The present disclosure also envisages a vehicle comprising a system (100) for derating a headlamp of the vehicle. The system (100) comprises a temperature sensing unit (105), a control unit (110) and an actuator (115). The temperature sensing unit (105) is configured to sense the temperature of the headlamp to periodically generate a sensed temperature value. The control unit (110) is configured to communicate with the temperature sensing unit (105) to receive the sensed value. The control unit (110) is configured to compare the sensed value with a predetermined threshold value to generate a compared signal. The actuator (115) is configured to communicate with the control unit (110) and the headlamp. The actuator (115) is configured to receive the compared signal and switch off the headlamp based on the compared signal.
Providing the system (100) in the vehicle allows the headlamp to run at a constant current supply. More specifically, unlike the headlamp without the system (100), of the present disclosure, the headlamp doesn’t shine bright at start and eventually heat up faster during cold start. Thus, damage to the headlamp is prevented. Further, uniform light output in the entire operating range of the vehicle at all weather and climatic conditions is ensured while ensuring that no fluctuations of light intensity happen with respect to temperature.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.

TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a system for derating a headlamp:
• which derates the headlamp at a predetermined temperature beyond which the headlamp is prone to damage so that the life of the headlamp is not affected; and
• which ensures uniform light output in the entire operating range of the headlamp at all weather and climatic conditions while ensuring that no fluctuations of light intensity happen with respect to the operational temperature of the headlamp.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1. A system (100) for derating a headlamp, said system comprising:
• a temperature sensing unit (105), configured to sense the temperature of the headlamp to periodically generate a sensed temperature value;
• a control unit (110) communicating with said temperature sensing unit (105) to receive said sensed value, said control unit (110) configured to compare said sensed temperature value with a predetermined threshold value to generate a compared signal when said sensed temperature value is greater than said predetermined threshold value; and
• an actuator (115) communicating with said control unit (110) and said headlamp, said actuator (115) configured to receive said compared signal and switch off the headlamp based on said compared signal.
2. The system (100) as claimed in claim 1, wherein said temperature sensing unit (105) is provided within said headlamp.
3. The system (100) as claimed in claim 1, wherein said temperature sensing unit (105) includes:
o a temperature sensor for sensing the temperature of the headlamp to periodically generate a sensed temperature signal; and
o a converter communicating with said temperature sensor, said converter configured to receive said sensed temperature signal, and further configured to convert said sensed temperature signal to said sensed temperature value.
4. The system (100) as claimed in claim 1, wherein said control unit (110) includes:
o a repository (112) configured to store said predetermined threshold value; and
o a comparator (114) configured to communicate with said temperature sensing unit (105) to receive said sensed temperature value, and further configured to communicate with said repository (112) to receive said predetermined threshold value, said comparator (114) configured to compare said sensed temperature value with said predetermined threshold value to generate said compared signal when said sensed temperature value is greater than predetermined threshold value.
5. The system (100) as claimed in claim 4, wherein said comparator (114) is configured to generate said compared signal when said sensed temperature value exceeds a predetermined threshold value of 110°C.
6. The system (100) as claimed in claim 1, which includes an anodized heat sink configured to facilitate mounting of the headlamp thereon, said heat sink being configured to absorb heat dissipated by the headlamp.
7. The system (100) as claimed in claim 6, wherein said heat sink includes a fan-and-motor assembly configured to enable air circulation in said heat sink.
8. The system (100) as claimed in claim 1, which includes a thermal paste applied on the headlamp for dissipating heat released by the headlamp.
9. A vehicle comprising a system (100) for derating a headlamp of the vehicle, said system (100) comprising:
• a temperature sensing unit (105), configured to sense the temperature of the headlamp to periodically generate a sensed temperature value;
• a control unit (110) communicating with said temperature sensing unit (105) to receive said sensed value, said control unit (110) configured to compare said sensed temperature value with a predetermined threshold value to generate a compared signal when said sensed temperature value is greater than said predetermined threshold value; and
• an actuator (115) communicating with said control unit (110) and said headlamp, said actuator configured to receive said compared signal and switch off the headlamp based on said compared signal.
Dated this 10th day of August, 2022

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT CHENNAI