Illuminated Keyboard Backlight Layout for Uniform Keycap Brightness
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Solution Overview
Problem
Direct-type illuminated keyboards suffer from poor brightness uniformity on keycaps due to light beams primarily projecting to the central region, resulting in high brightness in the center and low brightness in the peripheral regions.
Innovation Solution
The design incorporates a membrane circuit board, a base plate with strategically positioned through holes, a key structure with an elastic member, a backlight module featuring a direct-type light-emitting element and a light guide plate, and a reflective layer that aligns with the light-emitting element and through holes to redirect light for even distribution across the keycap.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a direct-type light-emitting element is used to illuminate the keycap, then the light emission control is precise and the keycap can be illuminated on demand, but the light beam primarily projects to the central region resulting in poor brightness uniformity
Solution Approach 1:
A light guide plate is introduced as an intermediary component between the direct-type light-emitting element and the keycap. The light guide plate receives light from the light-emitting element and guides it to illuminate the peripheral region of the keycap, achieving uniform brightness distribution without requiring a complex indirect-type lighting structure
Solution Approach 2:
The light guide plate is positioned specifically in the peripheral region of the keycap where brightness is insufficient. This local illumination approach targets only the dark peripheral areas while maintaining the simplicity of direct-type lighting in the central region, thereby improving overall brightness uniformity without adding excessive complexity
2Illumination intensity
If the light-emitting element is aligned with the center of the keycap, then the light emission structure is simple, but the central region has high brightness and the peripheral region has low brightness
Solution Approach 1:
The light guide plate serves as a mediator that decouples the alignment requirements. The light-emitting element can remain simply aligned with the keycap center, while the light guide plate redirects the light to the peripheral region, achieving both simple manufacturing and improved peripheral brightness
Solution Approach 2:
The solution transitions from direct vertical illumination to a multi-dimensional light path involving the light guide plate. Light travels from the central light-emitting element, through the light guide plate structure, and emerges in the peripheral region, adding a spatial dimension to the illumination path without complicating the alignment process
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 configuration enhances brightness uniformity across the keycap by reducing central brightness and increasing peripheral brightness, resulting in improved visual clarity of characters on the keycaps.
Implementation Method 1
a first reflective layer, disposed over, beneath, or over and beneath the membrane circuit board and is substantially aligned with the first through hole
Data Source
AI summary
An illuminated keyboard includes a membrane circuit board, a base plate, a key structure, a backlight module and a first reflective layer. The base plate is disposed beneath the membrane circuit board and has a first through hole and a plurality of second through holes adjacent to the first through hole. The key structure is disposed over the membrane circuit board and includes an elastic member. The backlight module is disposed beneath the base plate. The backlight module includes: a direct-type light-emitting element, substantially aligned with the first through hole and misaligned with a trigger portion of the elastic member; and a light guide plate, laterally adjacent to the direct-type light-emitting element. The first reflective layer is disposed over, beneath, or over and beneath the membrane circuit board and is substantially aligned with the first through hole.