LED Backlight MOSFET Driving for Fine Local Dimming Zones
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Solution Overview
Problem
Conventional thin film transistor (TFT)-based active matrix driving for LED backlight units faces challenges in high current/high voltage driving and fine wiring limitations, leading to difficulties in expanding local dimming zones and increasing manufacturing costs.
Innovation Solution
A display device with multiple individual unit compartment areas driven by an active matrix scheme, utilizing a driver with a driving MOSFET and a switching unit comprising switching MOSFETs connected in parallel, eliminating the need for a separate capacitor and thin film transistor (TFT) manufacturing, and using a glass substrate for improved wiring and cost efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thin film transistor (TFT) is used for active matrix driving, then local dimming zones can be controlled, but high current/high voltage driving capability is insufficient
Solution Approach 1:
The patent changes the transistor type from TFT to MOSFET, which has superior electrical parameters including higher current carrying capacity and voltage handling capability. This parameter change enables the backlight driver to achieve both local dimming control and high current/high voltage driving capability simultaneously, resolving the contradiction between control functionality and power delivery capability.
2Extent of automation
If thin film transistor (TFT) manufacturing process is used, then active matrix driving is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the capacitor component from the traditional TFT-based active matrix circuit and replaces it with a MOSFET-based design that eliminates the need for separate capacitor manufacturing. This extraction simplifies the manufacturing process by removing one of the most complex steps (capacitor formation) while maintaining the active matrix driving capability, thus resolving the contradiction between automation extent and device complexity.
Solution Approach 2:
The patent uses a MOSFET structure that can be manufactured using standard semiconductor fabrication processes, replacing the complex TFT-capacitor combination. The MOSFET design copies the essential functionality of the TFT-based active matrix driver but with simpler manufacturing requirements, reducing process complexity while maintaining driving capability.
3Extent of automation
If PCB substrate is used for TFT formation, then active matrix driving is possible, but fine wiring capability is limited
Solution Approach 1:
The patent transitions from a PCB-based mechanical wiring system to a semiconductor-based MOSFET circuit system. This substitution enables fine wiring capabilities because semiconductor fabrication can create much finer conductive paths and more dense interconnections compared to PCB trace routing, while maintaining active matrix driving functionality.
4Device complexity
If conventional LED packages with parallel connection are used, then simple structure is achieved, but power efficiency is low
Solution Approach 1:
The patent segments the backlight unit into multiple independently controllable unit compartment areas, each with its own MOSFET driver. This segmentation enables localized dimming control, which improves power efficiency by turning off or dimming specific regions rather than the entire backlight, while maintaining a relatively simple overall structure through modular design.
Solution Approach 2:
The patent implements dynamic control of individual LED units or groups through MOSFET switching, allowing the backlight to adapt its luminance distribution in real-time. This dynamic capability improves power efficiency by matching the backlight output to the actual display content requirements, while the parallel connection structure maintains simplicity in the electrical configuration.
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 configuration enhances the number of local dimming zones, improves contrast ratio, and reduces manufacturing costs by eliminating the need for TFT manufacturing, while enabling efficient high-luminance driving and fine wiring capabilities.
Implementation Method 1
LED (light emitting diode), which is a well-known semiconductor light-emitting device that converts electric current into light
Data Source
AI summary
The present invention is applicable to a display device-related technical field, and relates to, for example, a flat lighting device and a display device using a light-emitting diode (LED). The present invention relates to a display device including a plurality of individual unit compartment regions, comprising: at least one light-emitting diode provided in the individual unit compartment regions; a gate-on voltage line connected to the light-emitting diode; a scan line for applying a common voltage to the plurality of individual unit compartment regions; a data line for applying individual switching voltages to the plurality of individual unit compartment regions; a driving unit including a driving MOSFET device connected to the light-emitting diode; and a switching unit including a switching MOSFET device connected to the scan line and the data line to perform a switching operation.