Oven Cavity LED Lighting with Air-Cooled Light Guides
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Solution Overview
Problem
Conventional LED lighting in oven cavities is limited by the inability of LEDs to operate effectively at high temperatures, and existing solutions either rely on cooling airflow that stops illumination when the door is opened or fail to maintain effective cooling due to high oven wall temperatures.
Innovation Solution
An LED lighting device with a casing attached to the oven side wall, featuring thermally insulated LEDs and light guides made of high-temperature materials, coupled with a cooling airflow system that directs air to the LEDs through a network of channels, ensuring they operate below the critical temperature threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional lamps are used to light the oven cavity, then the lighting can operate at high temperatures, but the energy consumption is high and the lifespan is short
Solution Approach 1:
The patent changes the operating parameters of the lighting system by using LEDs that operate at lower temperatures than conventional lamps, and introduces a cooling system with variable airflow to maintain optimal LED operating conditions. The cooling airflow rate can be adjusted based on oven temperature conditions to optimize energy efficiency.
Solution Approach 2:
The patent introduces a cooling airflow as an intermediary medium to transfer heat away from the LEDs. The cooling system acts as a mediator between the heat-generating LEDs and the oven environment, enabling LEDs to operate at lower temperatures while the oven cavity maintains high temperatures for cooking.
2Temperature
If LEDs are mounted inside a cooled door, then the LEDs can be cooled effectively, but the oven cavity is not illuminated when the door is opened
Solution Approach 1:
The patent segments the lighting function from the door cooling system by mounting LEDs on the interior wall of the oven cavity rather than in the door. This allows the cooling system to serve the LEDs independently while the illumination function remains available in the oven cavity regardless of door position.
Solution Approach 2:
The patent extracts the LEDs from the door structure and relocates them to the oven cavity interior wall. This separation allows the door to be opened or closed without affecting the illumination function, while the cooling airflow continues to service the LEDs through dedicated cooling channels.
3Device complexity
If LEDs are thermally connected to oven walls, then the structure is simplified, but the oven walls may reach high temperatures preventing effective LED cooling
Solution Approach 1:
The patent introduces a cooling airflow as an intermediary between the LEDs and the oven wall environment. The cooling channels provide a dedicated thermal pathway that mediates heat transfer away from the LEDs, preventing direct thermal coupling with the high-temperature oven wall while maintaining structural simplicity.
Solution Approach 2:
The patent uses a pneumatic cooling system where forced airflow through channels provides active cooling to the LEDs. This pneumatic cooling mechanism allows effective heat removal without requiring complex thermal management structures, maintaining simplicity while controlling LED operating temperature.
4Duration of action of stationary object
If a cooling airflow system is introduced to cool the LEDs, then the LED lifespan is extended, but the device complexity increases
Solution Approach 1:
The patent makes the cooling airflow system multi-functional by using the same cooling air that cools the LEDs and also serves to cool the oven door when closed. This universal cooling approach extends LED lifespan while minimizing the increase in device complexity by sharing the cooling resource across different thermal management needs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides consistent illumination of the oven cavity even when the door is open and prevents overheating of the LEDs, ensuring reliable operation and extended lifespan.
Implementation Method 1
a system for cooling the door (18). The cooling system includes a fan (30) arranged on the top wall (22) and connected to an air conveyor (32) that conveys the cooling airflow generated by the fan (30) into a chamber (34) formed in the door (18)
Implementation Method 2
The LEDs are thermally connected to the outside walls of the oven. The oven walls act as a heat sink to keep the temperature of the LEDs relatively low
Data Source
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AI summary
LED lighting device for lighting the cavity (16) of an oven (10), comprising: a casing (36) having a back wall (38) and an open side opposite said back wall (38), a printed circuit board (40) bearing a plurality of LEDs (42) spaced apart from one another in a longitudinal direction, in which the printed circuit board (40) is attached to the open side of said casing (36) and is removed from said back wall (38) such as to form a gap (46) between said printed circuit board (40) and said back wall (38), a plurality of light guides (48) that pass through respective holes in said back wall (38), in which the light guides (48) emerge outside said casing (36) orthogonally to said back wall (38) and have respective internal frontal extremities (50) facing the respective LEDs (42), and an air supply duct (52) for supplying a cooling airflow into said gap (46).