Double-Sided PCB Backlighting for Uniform Illumination
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Solution Overview
Problem
Conventional single-side LED backlight modules face challenges in providing uniform backlight due to the irregular shape of optical reflectors required to accommodate taller electronic components, leading to overheating issues and increased manufacturing costs.
Innovation Solution
A double-sided circuit board design with thermal conducting material, where LED components are mounted on one side and electronic components on the other, allowing for a smooth planar reflector and enhanced thermal dissipation through ventilation windows and a thermal dissipating planar structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electronic components are mounted on the same side as LED components, then the circuit board layout is simplified, but the optical reflector must be molded into irregular shape to accommodate taller electronic components, resulting in non-uniform backlight and increased manufacturing costs
Solution Approach 1:
The circuit board is divided into two surfaces: the first surface mounts LED components and the optical reflector, while the second surface mounts electronic components. This segmentation allows each surface to be optimized independently, enabling a planar reflector on the first surface while accommodating taller electronic components on the second surface.
Solution Approach 2:
The patent transitions from a single-side (2D) component arrangement to a double-sided (3D) component arrangement. By utilizing both surfaces of the circuit board, the system can accommodate components of varying heights without compromising the planarity of the reflector, as the electronic components are positioned on the opposite side from the optical components.
2Temperature
If a metal core printed circuit board is used to handle heat dissipation, then LED component heat is discharged effectively, but the irregular reflector shape causes non-uniform backlight illumination
Solution Approach 1:
The circuit board is segmented into functional zones: the first surface contains LED components and the optical reflector for uniform light diffusion, while the second surface contains electronic components and thermal conducting material for heat dissipation. This segmentation allows independent optimization of optical performance and thermal management.
Solution Approach 2:
Thermal conducting material is introduced as an intermediary substance between the electronic components and the circuit board substrate. This thermal interface material enhances heat transfer from the electronic components to the board, improving overall heat dissipation efficiency without affecting the optical path on the first surface.
3Illumination intensity
If the reflector is kept at an optimal distance from LED components for satisfactory light diffusion, then uniform backlight is achieved, but the maximum height of electronic components exceeds this optimal distance, forcing irregular reflector shaping
Solution Approach 1:
The patent resolves the height conflict by transitioning to a three-dimensional component arrangement where electronic components are positioned on the second surface of the circuit board, away from the optical path on the first surface. This spatial separation in the vertical dimension allows the reflector to maintain its optimal distance from LED components while accommodating taller electronic components on the opposite side.
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
This design ensures uniform backlight illumination, reduces manufacturing complexity and costs, and effectively manages heat dissipation to prevent overheating, maintaining component performance and extending lifespan.
Implementation Method 1
a thermal conducting core layer to discharge heat generated by the light source components
Implementation Method 2
a thermal dissipating planar structure to cover the second surface of the circuit board. The planar structure has a protruding portion on the inner side to be in contact with the thermal conducting core layer
Data Source
AI summary
Apparatuses for backlighting and manufacturing processes thereof are disclosed. There is provided a backlight module. The backlight module comprises a double-sided circuit board with thermal conducting material as one of the core layers; a plurality of light source components mounted on the first surface of the circuit board; and, a plurality of electronic components mounted on the second surface of the circuit board. The thermal conducting core layer discharges heat generated by the light source components. The circuit board has at least one window on the surface layer at the second surface to expose the thermal conducting core layer for thermal dissipation. As such, the component heights on the illuminating side of the circuit board are unified, and the reflector can be made as a smooth planar sheet to provide a more uniform backlight illumination compared to a single-side circuit board design. Further, such an arrangement reduces the complexity in manufacturing the reflector and hence the cost thereof.