Driver Circuit for Light Emitting Thyristors
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Solution Overview
Problem
Conventional self-scanned print heads with light emitting thyristors suffer from long rise times due to parasitic capacitance, leading to inefficient energy exposure and prolonged printing times, especially in high-speed operations.
Innovation Solution
A driver circuit configuration that includes a common terminal, resistors, and a switch for each light emitting thyristor, allowing for controlled ON/OFF operation to minimize the impact of parasitic capacitance, ensuring efficient energy exposure and reduced printing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If light emitting thyristors are driven in sequence with commonly connected anodes and cathodes, then the structure is simple, but the parasitic capacitance forms a large capacitance causing long delay time and shortening the light emission period
Solution Approach 1:
The patent divides the common anode/cathode connection into separate individual connections for each light emitting thyristor. Each thyristor has its own anode and cathode terminals connected to the driver circuit, eliminating the parasitic capacitance accumulation that occurs with common connections. This segmentation resolves the contradiction by maintaining structural simplicity while eliminating the time loss caused by large parasitic capacitance.
2Device complexity
If light emitting thyristors have commonly connected anodes and cathodes, then the circuit configuration is simplified, but the large parasitic capacitance reduces the time period for light emission
Solution Approach 1:
The patent implements separate anode and cathode connections for each light emitting thyristor rather than common connections. This segmentation eliminates the parallel parasitic capacitance that would otherwise form with common connections, thereby extending the light emission period while maintaining reasonable circuit complexity through systematic individual connections.
3Ease of manufacture
If conventional driver circuits are used with light emitting thyristors, then the design is straightforward, but the long rise time causes loss of exposure energy and poor printing operation
Solution Approach 1:
The patent employs individual driver circuits for each light emitting thyristor with separate anode and cathode control lines. This segmented approach enables precise control of each thyristor's switching timing, reducing rise time and minimizing exposure energy loss while maintaining straightforward design through modular driver architecture.
Solution Approach 2:
The driver circuit applies trigger signals to the gate electrodes of light emitting thyristors in advance to ensure rapid turn-on. By controlling the gating sequence and timing beforehand, the circuit minimizes the rise time and prevents loss of exposure energy during the critical switching transition period.
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 proposed configuration significantly reduces the time required for light emitting thyristors to turn on, eliminating energy loss and improving printing efficiency, making it suitable for high-speed operations and full-color image forming applications.
Implementation Method 1
Each light emitting thyristor is energized by a trigger signal applied to its gate electrode, so that current flows from anode to cathode to emit light.
Data Source
AI summary
A driver apparatus drives aligned light emitting thyristors. Each thyristor includes an anode, a cathode, and a gate. The driver apparatus includes a common terminal, a first resistor, a second resistor, and a switch. Each thyristor is disposed at a first position where the anode is connected to the first potential and the cathode is connected to the common terminal, or a second position where the anode is connected to the common terminal and the cathode is connected to the second potential. The first resistor is connected between the first potential and the common terminal. The second resistor is connected between the common terminal and the second potential. The switch is connected at a third position where the switch is connected between the between the first potential and the common terminal, or a fourth position where the switch is connected between the common terminal and the second potential.