Backlighting Color Temperature Control via Segmented LED Arrays
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Solution Overview
Problem
Conventional LEDs face challenges in adjusting color temperature for backlighting applications, as their emission does not follow a black-body spectrum, leading to difficulties in CCT dimming due to binning, age, and temperature drift effects, making it hard to match lighting scenarios across different environments.
Innovation Solution
The use of unpackaged LEDs on a circuit substrate with adjustable light sources and phosphor application allows for customizable color temperature settings, enabling adaptation to various environments through adjustable brightness, color, and intensity, with sensors detecting environmental lighting to automatically adjust backlighting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional LEDs are used for backlighting, then energy consumption is reduced and robustness is improved, but color temperature adjustment becomes difficult due to non-black-body emission spectrum
Solution Approach 1:
The patent segments the backlighting system into multiple independent LED chips with different color temperatures (e.g., warm white, neutral white, cool white LEDs). Each LED chip type emits a specific color temperature range, and by selectively controlling individual segments (LED groups), the system achieves flexible color temperature adjustment without requiring complex spectral conversion.
Solution Approach 2:
The patent combines multiple LED chip types with different color characteristics into a single backlighting module. By merging warm white, neutral white, and cool white LED chips in close proximity, the system creates a composite light source that can emit a broad spectrum of color temperatures, effectively simulating black-body radiation characteristics through the superposition of multiple discrete spectral components.
2Measurement precision
If feedback loop systems with color sensors are used to control color output, then color accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-binning LED chips into distinct color temperature groups during manufacturing (e.g., 2700K, 4000K, 6504K categories). This pre-sorting ensures that each LED chip falls within a specific color temperature range, eliminating the need for complex real-time color sensing and feedback control. The system achieves color accuracy through upfront classification rather than continuous measurement and adjustment.
Solution Approach 2:
The patent replaces expensive, complex feedback loop systems with simple, inexpensive LED chip selection and control circuitry. By using readily available LED chips with known color temperature characteristics and basic control electronics, the system achieves comparable color accuracy without requiring sophisticated sensors, microcontrollers, or continuous calibration mechanisms.
3Stability of the object's composition
If binning, age and temperature drift effects are considered, then color stability is improved, but control difficulty increases
Solution Approach 1:
The patent applies local quality by assigning different thermal management characteristics to different LED chip groups. LEDs with similar color temperature characteristics are grouped together and managed as units, allowing targeted thermal compensation for each group based on their specific drift characteristics. This localized approach simplifies control compared to managing each LED individually while maintaining overall color stability.
Solution Approach 2:
The patent compensates for temperature drift and aging effects by dynamically adjusting the drive current and duty cycle of individual LED groups. When temperature increases cause color shift, the system changes the electrical parameters (current, pulse width) of affected LED groups to counteract the drift. This parameter adjustment approach maintains color stability without requiring mechanical or structural modifications.
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 solution enables flexible and customizable backlighting that can adapt to different environments, ensuring user comfort by adjusting color temperature settings, whether manually or automatically, enhancing the usability of devices like keyboards in diverse lighting conditions.
Implementation Method 1
a fourth LED type comprising a blue LED and a phosphor, the phosphor converting blue light from the blue LED to wavelengths corresponding to a color temperature between 2000K and 3000K
Data Source
AI summary
An apparatus includes a housing including a plurality of light sources to provide backlighting for the apparatus. A first portion of the plurality of light sources is configured to provide a first color temperature setting. A second portion of the plurality of light sources is configured to provide a second color temperature setting. The apparatus includes a controller including one or more processors configured to execute instructions stored on memory, which when executed, cause the one or more controllers to set at least one of an overall color temperature setting for the backlighting of the apparatus, or a partial color temperature setting for the backlighting of the apparatus.