μ-LED Dual-Gate PWM Control for Compact Pixel Addressing
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Solution Overview
Problem
The challenge in developing μ-LED displays for automotive and augmented reality applications lies in the limited space for light-generating components, which complicates the addressing and control of individual pixels, and requires innovative solutions for efficient light management and control.
Innovation Solution
The proposed solution involves a device for electronic control and power supply of μ-LEDs, utilizing a dual-gate transistor connected in series with the μ-LED, where the additional control gate of the dual-gate transistor is modulated with a PWM signal to control the brightness of the μ-LED, and a select-hold circuit with a charge accumulator to manage the current conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional control circuits are used for μ-LED displays, then the display can be controlled, but the space requirements and device complexity increase
Solution Approach 1:
The patent combines the control gate and select gate functions into a single dual-gate transistor structure. The first control gate receives control signals while the second control gate receives select signals, merging what would traditionally require separate transistors into one integrated component. This reduces the number of discrete components and simplifies the overall circuit architecture while maintaining full control capability over the μ-LED array.
Solution Approach 2:
The dual-gate transistor serves multiple functions simultaneously: it acts as a control element for brightness modulation via PWM on the first control gate, and as a selection element for row or column addressing on the second control gate. This multi-functionality eliminates the need for separate control and selection circuits, reducing device complexity while preserving operational capabilities.
2Manufacturing precision
If more control components are added to manage μ-LED pixels, then individual pixel control improves, but the space requirements increase
Solution Approach 1:
The patent merges control and selection functionality into a single dual-gate transistor per pixel row or column. By using the first control gate for PWM modulation and the second control gate for selection, the design eliminates the need for separate control transistors that would otherwise be required for each pixel, thereby reducing the overall area while maintaining precise addressing capability.
Solution Approach 2:
The patent employs a matrix addressing scheme where control is achieved through two-dimensional row and column selection rather than individual pixel control. The dual-gate transistor enables this by handling both selection and control signals, allowing precise pixel addressing through the intersection of selected rows and columns, which significantly reduces the number of components needed compared to direct pixel control.
3Illumination intensity
If PWM modulation is implemented for brightness control, then brightness dynamic range improves, but the control circuit complexity increases
Solution Approach 1:
The first control gate of the dual-gate transistor is designed to receive PWM modulation signals for brightness control while the same gate structure is used for conventional voltage control. This multi-functional approach allows the circuit to achieve wide brightness dynamic range through PWM without requiring separate dedicated PWM control circuits, thereby limiting the increase in overall control circuit complexity.
Solution Approach 2:
The dual-gate transistor itself acts as an intermediary that translates PWM control signals into appropriate current modulation for the μ-LED. The transistor's unique dual-gate structure allows it to process PWM signals directly at the gate level, converting them into the necessary current variations without requiring additional PWM decoding or conversion circuits, thus simplifying the overall control architecture.
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 allows for efficient pulse-width modulation of μ-LEDs, reducing space requirements and improving brightness control, enabling high dynamic brightness range and contrast necessary for automotive and augmented reality applications.
Implementation Method 1
the additional control gate of the dual-gate transistor is modulated with a PWM signal to control the brightness of the μ-LED
Implementation Method 2
μ-LED, μ-LED device
Implementation Method 3
a select-hold circuit with a charge accumulator to manage the current conduction
Data Source
AI summary
The invention relates to various aspects of a μ-LED or a μ-LED array for augmented reality or lighting applications, in particular in the automotive field. The μ-LED is characterized by particularly small dimensions in the range of a few μm.