Backlit PCB Countersunk Holes Light Diffusion
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Solution Overview
Problem
Existing printed circuit boards with integrated backlighting systems face challenges in minimizing thickness, leading to constraints in equipment construction and ineffective light diffusion due to the need for space between the circuit and the support, resulting in limited visibility and increased overall dimensions.
Innovation Solution
A printed circuit board design with countersunk through holes that house LEDs, where the hole opening on the emissive side is larger than the LED, and the inner wall is made of reflective material to act as a diffuser, allowing for integrated backlighting without additional space between the circuit and support, enabling reduced thickness and improved light diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional flat through holes are used for mounting LEDs, then the LED can be mounted on the printed circuit board, but the light diffusion is insufficient and a larger interspace is required between the circuit and support
Solution Approach 1:
The patent applies curvature by using countersunk holes with conical surfaces instead of flat cylindrical holes. The conical inner surface of the countersunk hole redirects light rays at various angles, transforming the narrow directional light beam into a wider diffused pattern, thereby improving light diffusion effectiveness without requiring additional interspace.
2Illumination intensity
If a larger interspace is maintained between the printed circuit board and the support, then better light diffusion is achieved, but the overall thickness of the backlit equipment increases
Solution Approach 1:
The conical countersunk hole geometry enables effective light diffusion within the available thickness by redirecting light internally. This eliminates the need for additional interspace, allowing the support to be positioned closer to the circuit board and thereby reducing the overall thickness of the backlit equipment while maintaining effective light diffusion.
3Illumination intensity
If the opening of the hole on the emissive side is made larger than the LED, then light diffusion is improved, but the structural integrity of the circuit board may be compromised
Solution Approach 1:
The countersunk conical geometry distributes the stress around the hole opening more evenly compared to a straight cylindrical hole. The tapered walls provide gradual stress distribution and better mechanical anchoring for the LED, maintaining structural integrity while allowing a larger opening on the emissive side for improved light diffusion.
Solution Approach 2:
The LED is nested within the countersunk hole structure, where the conical surface provides both mechanical support and optical function. This nested configuration allows the LED to be securely housed while the larger opening diffuses light effectively, and the conical walls provide structural reinforcement around the opening.
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 allows for a backlit electronic device and capacitive button with reduced thickness and enhanced light visibility, as the countersunk holes and reflective materials optimize light emission and diffusion within the circuit board thickness, eliminating the need for interspace between the circuit and support.
Implementation Method 1
the inner wall is made of reflective material to act as a diffuser
Data Source
Figure 1~1a
Figure 1b
Figure 2
AI summary
Printed circuit (4) comprising a substrate (1) with a first side (11) suitable for the application of the network of connections (43) and the assembly of components, and one or more through holes (2), at least one of said holes (2) comprising a first section (23) suited to house a lighting body (3) facing towards the emissive side (12) of said substrate (1), and a second, larger section (24) for diffusion of the light emitted by said lighting body (3).