LED Backlight Frequency Segmentation for Uniformity Control
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Solution Overview
Problem
Existing methods for controlling the back-lighting source in LCD panels require multiple sensors to ensure uniformity, increasing cost and complexity, as they rely on a single frequency for all LED strips despite varying distances from sensors.
Innovation Solution
Assigning different frequencies to individual LED strips or groups of strips allows for monitoring and adjustment of spatial uniformity and color levels using pulse-width modulation, with sensors detecting frequency-dependent brightness information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are used to monitor uniformity at different locations, then measurement precision of spatial uniformity is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the LED backlight source into multiple regions (first region and second region) with different driving frequencies. This segmentation allows a single sensor to distinguish between different spatial locations through frequency differentiation, eliminating the need for multiple sensors at different locations while maintaining spatial uniformity monitoring capability.
Solution Approach 2:
The patent introduces frequency as an additional dimension to distinguish spatial locations. Instead of placing multiple sensors at different physical locations, the system uses frequency modulation to encode spatial information, allowing one sensor to monitor multiple regions by detecting their respective driving frequencies.
2Device complexity
If a single frequency is used for all LED strips, then device complexity is reduced, but measurement precision of spatial uniformity deteriorates
Solution Approach 1:
The patent divides the LED strips into different groups (first and second regions) and assigns different driving frequencies to each group. This segmentation enables the system to maintain simple single-frequency operation within each region while achieving precise spatial uniformity monitoring across the entire backlight source through frequency differentiation.
3Manufacturing precision
If multiple sensors are placed at different sites, then brightness uniformity across the back-lighting source is improved, but cost increases
Solution Approach 1:
The patent segments the backlight source into multiple regions driven at different frequencies, allowing a single sensor to monitor brightness uniformity across the entire source by detecting frequency-specific signals. This eliminates the need for multiple sensors at different sites while maintaining manufacturing precision for brightness uniformity.
Solution Approach 2:
The patent uses driving frequency as an intermediary to transfer spatial location information to the sensor. The frequency acts as a mediator that enables the sensor to distinguish between different spatial regions without requiring physical placement at multiple locations, thereby reducing cost while maintaining monitoring precision.
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 approach reduces the need for multiple sensors, enhancing cost-effectiveness while ensuring accurate monitoring and adjustment of brightness and color uniformity across the back-lighting source.
Implementation Method 1
A sensor is used to sense the color levels in the LED strips
Data Source
AI summary
The present invention uses different frequencies to drive the LED strips in the back-lighting source so that the spatial uniformity of the back-lighting source as well as the color levels in the source can be monitored and adjusted. Each individual strip is assigned to a different frequency. Alternatively, the strips are divided into groups and each group is assigned to a different frequency. A group may comprise two or more strips. Furthermore, some groups may have more strips than the other groups and the number of LEDs in one strip may be different from the number in other strips. The brightness uniformity and the color levels in the back-lighting source are sensed by one or more groups of color sensors in R, G and B. The assignment of driving frequencies can be based on the location of the strips.