Keyboard Backlight Circuit Layout for Uniform Luminance
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Solution Overview
Problem
Current illuminated keyboards suffer from thickness issues and non-uniform light distribution, and the use of multiple resistors for controlling luminance increases costs when the number of light-emitting elements is large.
Innovation Solution
A backlight module design that divides the keyboard into regions corresponding to keycaps, adjusts light guiding regions and light emitting elements, and uses resistors with varying impedances to achieve uniform current flow and stable luminance across different areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple resistors are used to control luminance of each light-emitting element, then luminance control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges multiple separate resistor control circuits into a single unified control circuit. The controller generates control signals that regulate multiple light-emitting elements through one integrated circuit path, eliminating the need for individual resistors for each element. This combining approach maintains luminance control capability while reducing component count and system complexity.
Solution Approach 2:
The control circuit is designed with universal functionality to manage multiple light-emitting elements simultaneously. A single control circuit performs the luminance regulation function for all LED groups, making the system more efficient and cost-effective compared to dedicated control circuits for each element.
2Device complexity
If light-emitting elements are placed on a central light bar, then device complexity is reduced, but light uniformity deteriorates
Solution Approach 1:
The patent segments the light-emitting elements into multiple groups distributed across different locations on the circuit board rather than concentrating them on a single central light bar. Each group can be independently controlled, allowing for better light distribution uniformity across the keyboard surface while maintaining manageable system complexity through modular organization.
Solution Approach 2:
Different regions of the keyboard are provided with light-emitting elements according to their specific lighting requirements. The control circuit can adjust luminance differently for different key regions, achieving local optimization of light uniformity while maintaining overall system simplicity.
3Length of stationary object
If minimum thickness LED components are used, then keyboard thickness is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the physical and electrical parameters of the light-emitting elements and their arrangement to achieve thin keyboard profile. By carefully selecting LED specifications, adjusting mounting configurations, and optimizing circuit board layout, the design achieves reduced thickness while maintaining manufacturability and assembly feasibility within standard manufacturing tolerances.
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
Improves luminance and light uniformity while reducing the brightness difference between regions to a level undetectable by the human eye, thus enhancing the optical coupling and reducing component costs.
Implementation Method 1
a light guiding plate, disposed on the circuit board, including a first light guiding region and a second light guiding region
Implementation Method 2
a resistor unit, including a first resistor and a second resistor, the first resistor disposed on the first circuit, and the second resistor disposed on the second circuit
Implementation Method 3
a plurality of light emitting elements, disposed in parallel on the first line section and disposed in parallel on the second line section
Data Source
AI summary
A backlight module of an illuminated keyboard includes: a circuit board including a first circuit, a second circuit, a gathering portion and a conduction portion, and the first circuit having a first line section; a light guiding plate disposed on the circuit board, including a first light guiding region and a second light guiding region, and the first light guiding region disposed on the first line section; a plurality of light-emitting elements disposed in parallel on the first line section; and an resistor unit including a first resistor and a second resistor, the first resistor disposed on the first circuit, and the second resistor disposed on the second circuit. A sum of a line impedance of the first circuit and an impedance of the first resistor is substantially equal to a sum of a line impedance of the second circuit and an impedance of the second resistor.