LCD Backlight Uniformity via User Position Sensing
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Solution Overview
Problem
Liquid crystal display (LCD) devices with edge type backlight units face challenges in achieving uniform brightness due to variations in user location, leading to brightness deviations and non-uniform optical distribution.
Innovation Solution
A liquid crystal display device and method that utilize a location sensor to detect the user's position and adjust the brightness of each block of the backlight unit by calculating and applying a dimming value, ensuring uniform illumination across the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If an edge type backlight unit is used to make the display thinner and lighter, then the display structure becomes more compact, but brightness uniformity deteriorates due to variations in user location
Solution Approach 1:
The backlight unit is divided into multiple independently controllable blocks (first block, second block, third block, fourth block) corresponding to different viewing regions. Each block can be dimmed or brightened separately based on the detected user location, allowing the system to maintain brightness uniformity across the display while preserving the compact edge type structure.
Solution Approach 2:
The backlight controller dynamically adjusts the brightness of each block in real-time based on the user's location detected by the location sensor. The controller receives location information, determines which blocks need brightness adjustment, and controls the backlight driver to apply appropriate dimming values to specific blocks, thereby maintaining uniform brightness perception regardless of user position.
2Area of stationary object
If the backlight unit illuminates the entire display panel uniformly, then the display covers the full area, but brightness deviation occurs for users located at different positions
Solution Approach 1:
Different blocks of the backlight unit are assigned different brightness levels based on the user's location. When a user is detected at a specific position, the corresponding block is brightened while other blocks maintain normal or reduced brightness. This local adjustment ensures that the user always sees adequate brightness in their viewing area, eliminating brightness deviation across the display.
3Illumination intensity
If a location sensor and dynamic control system are added to correct brightness deviation, then brightness uniformity is improved, but device complexity increases
Solution Approach 1:
The backlight controller serves multiple functions: it receives location information from the location sensor, determines the user's viewing position, calculates appropriate brightness adjustments for different blocks, and controls the backlight driver. By consolidating these functions into a single controller, the system achieves brightness uniformity without proportionally increasing overall device complexity.
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 solution ensures a more uniform brightness perception for the user regardless of their location, enhancing the display's performance and user experience by dynamically adjusting the backlight intensity based on the user's position.
Implementation Method 1
an edge type backlight unit is a type of backlight unit where light generated at a side of a light guide panel is reflected by the light guide panel
Implementation Method 2
an optical sheet disposed on an upper part of the light guide panel and configured to change characteristics of the light emitted from the light guide panel
Data Source
AI summary
A liquid crystal display panel comprises a backlight unit including an optical assembly and configured to differentiate the liquid crystal display panel into a plurality of blocks and to illuminate light to each of the plurality of blocks; a location sensor configured to sense a location of a user watching the liquid crystal display panel; a backlight controller configured to output a dimming value corresponding to a brightness of each of the plurality of blocks according to a result of sensing by the location sensor; and a backlight driver configured to generate a driving current corresponding to the dimming value of each block and to provide the generated driving current to the backlight unit corresponding to each of the plurality of blocks.