Systems and methods for LED lens heating
Disclosed herein are systems and methods for melting cold weather related obstructions (snow, ice, frost, etc.) off of vehicle lamps by heating the lens of the housing, thus restoring the normal operating abilities (e.g., brake light illumination, running light illumination, turn signal illumination). This can allow for an efficient signaling process (e.g., to the following vehicle), thus raising the general level of safety on the roads.
1. A heating system for an LED vehicle lamp having a housing and a lens, comprising:
a circuit board positioned within the housing;
at least one LED mounted to the circuit board;
a heating element mounted to the circuit board, wherein the heating element comprises at least two resistors configured to heat the lens from within the housing;
at least two temperature sensors mounted to the circuit board, wherein the at least two temperature sensors include at least one temperature sensor positioned proximal to the heating element and at least one temperature sensor positioned distal to the heating element; and
a microcontroller in communication with the resistors and the temperature sensors, and having stored thereon computer-executable instructions which, when executed, cause the microcontroller to regulate voltage sent to the resistors based on incoming voltage, ambient temperature, and internal temperature of the housing,
wherein the microcontroller is configured to monitor readings from the at least two temperature sensors and determine the ambient temperature based on the readings.
2. The heating system of claim 1 , wherein the at least two temperature sensors include at least one elevated temperature sensor and at least one surface temperature sensor.
3. The heating system of claim 1 , wherein the microcontroller is configured to monitor the incoming voltage from the vehicle and regulate the voltage sent to the resistors using pulse width modulation.
4. The heating system of claim 1 , wherein the microcontroller is configured to overdrive the resistors when the internal temperature below a predetermined maximum temperature.
5. The heating system of claim 1 , wherein the microcontroller is configured to store the ambient temperature as data in a non-volatile memory.
6. The heating system of claim 5 , wherein the microcontroller is configured to calculate a delta value between the maximum temperature sensor reading and the minimum temperature sensor reading; and to use the last-stored data as the ambient temperature when the delta value is above a predetermined allowed maximum delta value.
7. The heating system of claim 1 , wherein the microcontroller is configured to activate the resistors when the ambient temperature is determined to be below a predetermined threshold temperature.
8. The heating system of claim 7 , wherein the predetermined threshold temperature is 10 degrees Celsius.
9. The heating system of claim 7 , wherein the microcontroller is configured to activate the resistors at full power for a predetermined length of time.
10. The heating system of claim 9 , wherein after the predetermined length of time, the microcontroller is configured to vary the voltage sent to the resistors to maintain a steady temperature above the freezing point of water.
11. The heating system of claim 1 , further comprising a fail-safe whereby the internal temperature is prevented from increasing above a predetermined maximum temperature.
12. The heating system of claim 11 , wherein the predetermined maximum temperature is 100 degrees Celsius.
13. The heating system of claim 1 , wherein the resistors comprise wire wound or metal oxide resistors.
14. The heating system of claim 1 , wherein the resistors comprise thick film resistors.
15. A heating system for an LED vehicle lamp having a housing and a lens, comprising:
at least two circuit boards positioned within the housing;
at least one LED mounted to a first circuit board;
a heating element mounted to a second circuit board, wherein the second circuit board is positioned adjacent to the lens, and wherein the heating element comprises at least two resistors configured to heat the lens from within the housing;
at least two temperature sensors mounted to the second circuit board, wherein the at least two temperature sensors include at least one temperature sensor positioned proximal to the heating element and at least one temperature sensor positioned distal to the heating element; and
a microcontroller in communication with the resistors and the temperature sensors, and having stored thereon computer-executable instructions which, when executed, cause the microcontroller to regulate voltage sent to the resistors based on incoming voltage, ambient temperature, and internal temperature of the housing,
wherein the microcontroller is configured to monitor readings from the at least two temperature sensors and determine the ambient temperature based on the readings.
16. The heating system of claim 15 , further comprising one or more spacers configured to position the second circuit board with the resistors and the temperature sensors closer to the lens.
17. The heating system of claim 15 , further comprising an inner lens optic and a lens optic holder positioned adjacent to the first circuit board.