Backlight Unit Local Brightness Control via Segmented LED Matrix
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Solution Overview
Problem
Conventional backlight units for LCDs cannot provide dynamic images due to the inability to independently control brightness across different regions of the display, as all light sources are connected and driven in series, limiting the ability to increase or decrease brightness locally.
Innovation Solution
A backlight unit with a plurality of light-emitting devices disposed on a substrate, an image analyzer to identify regions requiring brightness adjustments, and a control unit to independently drive and control these devices by adjusting voltage and current, allowing for localized brightness changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If all light sources are connected and driven in series, then the overall brightness can be controlled, but the ability to control brightness locally in specific regions is lost
Solution Approach 1:
The backlight unit is divided into multiple independently controllable light-emitting devices (LEDs) arranged in a matrix pattern. Each LED can be controlled separately through individual control lines, enabling local brightness adjustment in specific regions of the display without affecting other areas.
Solution Approach 2:
Different regions of the display can have different brightness levels by selectively controlling the intensity of individual LEDs or groups of LEDs. This allows bright regions and dark regions to coexist in the same display, matching the requirements of dynamic images with varying brightness distributions.
2Area of stationary object
If multiple CCFLs are arranged in series to cover larger display areas, then the display area is covered, but fine control of brightness in specific regions becomes impossible
Solution Approach 1:
Instead of using a small number of CCFLs covering large areas, the patent segments the backlight into numerous small LED units distributed across the entire display area. This segmentation enables precise control of brightness in specific regions while maintaining comprehensive area coverage.
Solution Approach 2:
The patent transitions from one-dimensional linear arrangement of CCFLs to a two-dimensional matrix arrangement of LEDs. This dimensional change allows independent control along both horizontal and vertical directions, enabling precise regional brightness control across the entire display area.
3Device complexity
If LEDs are connected in series to simplify the circuit, then the circuit structure is simplified, but independent control of individual LEDs is lost
Solution Approach 1:
The circuit is segmented into multiple independent control paths, with separate control lines for rows and columns of LEDs. This segmentation enables independent control of individual LEDs while maintaining a structured and manageable circuit architecture.
Solution Approach 2:
The patent introduces a control unit as an intermediary that receives image signals and generates appropriate control signals for driving individual LEDs. This control unit simplifies the overall system by centralizing the control logic while enabling fine-grained control of each LED through standardized control interfaces.
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
Enables the creation of dynamic images by allowing for precise control of brightness in specific regions, enhancing the display's ability to represent vivid and detailed images with partial increases or decreases in brightness.
Implementation Method 1
a light emitting diode (LED) is considered as a substitute for the CCFL. For example, LEDs emitting Lambertian light are used as a point light source for the direct light type backlight unit
Implementation Method 2
a diffusion plate 503 and a diffusion sheet 505 for projecting light emitted from the LED 500 onto a liquid crystal panel 510 to be uniform
Implementation Method 3
a reflection plate 502 for reflecting light that is emitted from the LED 500 to proceed toward the liquid crystal panel 510 located above LED 500
Implementation Method 4
a prism sheet 507 is provided to correct a light travelling route between the diffusion sheet 505 and the liquid crystal panel 510 and cause the emitted light to proceed toward the liquid crystal panel 510
Data Source
AI summary
A backlight unit for a dynamic image and a display employing the same are provided. The backlight unit is used for a light source of a display and includes light-emitting devices located separately on a substrate, an image analyzer which analyzes an image signal and extracts position information on a region requiring the relative increase or decrease of brightness, and a control unit which independently drives and controls the light-emitting devices located in a region corresponding to the position information inputted from the image board. Accordingly, the display employing the backlight unit can provide a more dynamic and realistic image.