Integrated Illumination Sensor for LCD Backlight Control
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Solution Overview
Problem
Conventional external-fitting illumination sensors for liquid crystal displays (LCDs) do not distinguish between different light sources, leading to suboptimal brightness control and reduced contrast ratio, especially in varying indoor lighting conditions, and increasing costs when modifying or adding sensors to match human visibility spectrum.
Innovation Solution
A thin film panel with an integrated illumination sensor featuring color filters and photo sensors on separate panels, where the photo sensors vary in resistance based on light energy passing through the filters, generating output voltages proportional to light intensity and type, and a driving device with a determination unit and signal controller to adjust backlight and gray voltage based on sensed light conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external illumination sensor is added to detect ambient light, then brightness control is improved, but the sensor cannot distinguish between different light sources leading to suboptimal control and increased cost
Solution Approach 1:
The illumination sensor is segmented into multiple photo sensors, each equipped with a specific color filter (red, green, blue). This segmentation allows each sensor to detect specific wavelength ranges, enabling the system to distinguish between different light sources based on their spectral characteristics while maintaining a relatively simple overall structure
Solution Approach 2:
Different regions of the sensor array are assigned different color filters with specific spectral response characteristics. This local quality differentiation enables each sensor element to have specialized detection capabilities, allowing the system to identify and respond to different types of light sources (natural light, fluorescent light, LED light) based on their unique spectral signatures
2Illumination intensity
If the backlight brightness is increased to maintain optimal image quality in bright environments, then visibility is improved, but light leakage increases causing eye fatigue and reduced contrast ratio
Solution Approach 1:
The system employs a feedback mechanism where the illumination sensor continuously monitors ambient light conditions and sends signals to the backlight control unit. The backlight brightness is dynamically adjusted based on this feedback, allowing the system to maintain optimal image quality and contrast ratio while minimizing light leakage and eye fatigue by using only the necessary brightness level
Solution Approach 2:
The backlight brightness is made dynamic rather than static. The system can adaptively adjust the backlight intensity in real-time based on detected ambient light conditions, transitioning smoothly between different brightness levels to maintain optimal viewing conditions while preventing excessive brightness that would cause light leakage and eye fatigue
3Device complexity
If the illumination sensor is integrated within the LCD panel, then cost is reduced and space is saved, but the sensor must share the panel structure with display elements
Solution Approach 1:
The illumination sensor is merged with the LCD panel structure by integrating it into the lower panel assembly. The sensor shares common structural elements and manufacturing processes with the display elements, allowing simultaneous fabrication and reducing overall device complexity and cost while maintaining manufacturing feasibility
Solution Approach 2:
The lower panel structure serves multiple functions: it acts as both the structural support for the display elements and as the housing for the illumination sensor. This multi-functionality reduces the need for separate components and simplifies the overall device architecture, making it easier to manufacture while achieving sensor integration
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 provides accurate brightness and color control by distinguishing light sources, reducing eye fatigue, and maintaining optimal image quality without increasing costs by integrating the illumination sensor within the LCD panel.
Implementation Method 1
a plurality of photo sensors formed on the second panel, wherein the photo sensors vary in resistance according to light energy passed through the color filters
Implementation Method 2
a plurality of color filters formed on the first panel, wherein the plurality of photo sensors are opposed to the plurality of color filters
Data Source
AI summary
A thin film panel, a driving device, and a liquid crystal display having the thin film panel and the driving device are provided. The thin film panel includes a first panel, a second panel, and an illumination sensor, wherein the illumination sensor includes a plurality of color filters formed on the first panel and a plurality of photo sensors formed on the second panel opposed to the plurality of color filters.