Backlight Optical Adjustment Surface for Keyboard Brightness
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Solution Overview
Problem
Current illuminated keyboard backlight apparatuses suffer from fixed beam angles of light emission, leading to lighting shadows and inefficient light energy utilization due to short distances between breakout holes, and limitations in increasing the number of light-emitting devices result in uneven brightness on keycaps.
Innovation Solution
The backlight apparatus features a light-guiding plate with through holes having optical adjustment surfaces, such as spherical or aspherical surfaces, that adjust the beam angle of light emitted by light-emitting devices, allowing for effective light energy utilization and uniform brightness across keycaps by positioning light-emitting devices within these holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If flat light incident surfaces are used in through holes, then the structure is simple and easy to manufacture, but the beam angle of light is fixed resulting in lighting shadows and inefficient light energy utilization
Solution Approach 1:
The patent applies spherical or aspherical optical adjustment surfaces instead of flat surfaces on the light incident surfaces of through holes. These curved surfaces modulate the beam angle of light emitted by light-emitting devices, transforming the fixed beam angle problem into an adjustable optical path that eliminates lighting shadows and improves light energy utilization efficiency.
2Illumination intensity
If the number of light-emitting devices is increased to improve brightness uniformity, then the brightness distribution on keycaps becomes more uniform, but the circuit board and bonding mechanism limitations prevent further increases
Solution Approach 1:
The patent applies different optical adjustment surfaces (spherical, aspherical, Fresnel) to different through holes based on their specific positions and optical requirements. This local optimization allows each light-emitting device to have tailored optical characteristics, achieving overall brightness uniformity without needing to increase the total number of devices, thus avoiding circuit board and bonding mechanism limitations.
3Adaptability or versatility
If the distance between breakout holes is reduced to accommodate keyboard design, then the keyboard layout flexibility improves, but lighting shadows occur behind the breakout holes
Solution Approach 1:
The curved optical adjustment surfaces on the through holes refract and redirect light paths to bypass the breakout holes. This optical modulation allows light to reach areas behind the breakout holes effectively, eliminating lighting shadows while maintaining the reduced distance between breakout holes for keyboard layout flexibility.
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 adjustable beam angle of the backlight apparatus enhances light energy utilization and ensures uniform brightness on keycaps, overcoming the limitations of fixed beam angles and uneven brightness in prior art.
Implementation Method 1
A first optical adjustment surface 1041 is formed on the light incident surface 1040 of a first specific through hole 104a... The first optical adjustment surface 1041 can be a first concave spherical surface, a first convex spherical surface, a first concave aspherical surface, a first convex aspherical surface, a first Fresnel concave arc surface, a first Fresnel convex arc surface...
Data Source
AI summary
A backlight apparatus used in an illuminated keyboard includes a light-guiding plate, a circuit board and a plurality of light-emitting devices all electrically bonded on the circuit board. The light-guiding plate has a plurality of through holes which each corresponds to one of the light-emitting devices. The circuit board is disposed on a back face of the light-guiding plate such that each light-emitting device is disposed within the corresponding through hole, and that a light-emitting side face of each light-emitting device faces a light incident surface of the corresponding through hole. A specific through hole of the through holes has an optical adjustment surface on the light incident surface thereof, and the optical adjustment surface has a curved surface central axis coaxial with a central optical axis of the corresponding light-emitting device.