Light-Emitting Chip DAC Voltage Source Switching
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Solution Overview
Problem
In conventional light-emitting devices with integrated light-emitting units and driving circuits, heat generated by the digital-to-analog converter (DAC) can affect the light emission properties of organic electroluminescent (EL) films, leading to unintended changes in light emission during periods when the device is not actively forming images.
Innovation Solution
The implementation of a light-emitting chip with a voltage source, a digital-to-analog converter, and a switch that disconnects the voltage source from the DAC when not in use, preventing heat generation and maintaining optimal light emission properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the voltage source is continuously connected to the DAC, then the DAC can immediately convert digital signals to voltage when needed, but heat is generated by the DAC during idle periods causing changes in light emission properties
Solution Approach 1:
The patent applies the dynamics principle by making the connection state between the voltage source and DAC changeable rather than fixed. A switch element is introduced to dynamically control the electrical connection, allowing the system to transition between connected and disconnected states based on operational requirements, thereby reducing heat generation during idle periods while maintaining quick response capability when needed.
Solution Approach 2:
The patent implements periodic action by intermittently connecting the voltage source to the DAC only when conversion is required. The switch is controlled to connect the voltage source to the DAC during active periods when digital-to-voltage conversion is needed, and disconnect during idle periods, creating a periodic on-off pattern that reduces overall heat generation while maintaining functional readiness.
2Ease of operation
If the voltage source is continuously connected to the DAC, then the system is ready for immediate operation, but power is consumed during idle periods when light emission is not required
Solution Approach 1:
The patent applies the dynamics principle by making the connection state between the voltage source and DAC changeable rather than fixed. A switch element is introduced to dynamically control the electrical connection, allowing the system to transition between connected and disconnected states based on operational requirements, thereby reducing heat generation during idle periods while maintaining quick response capability when needed.
Solution Approach 2:
The patent implements discarding and recovering by temporarily disconnecting the voltage source from the DAC during idle periods when conversion functionality is not needed. The switch element enables the system to discard the power consumption during these periods and recover by quickly reconnecting when operational needs arise, thus optimizing overall power efficiency.
3Reliability
If the voltage source is continuously connected to the DAC, then the system maintains operational readiness, but heat generated during idle periods causes unintended changes in light emission
Solution Approach 1:
The patent applies the taking out principle by extracting or removing the voltage source connection from the DAC during idle periods when conversion is not required. The switch element enables the voltage source to be separated from the DAC, eliminating the source of heat generation that would otherwise cause unwanted changes in light emission properties, while allowing quick reconnection when needed.
Solution Approach 2:
The patent implements preliminary anti-action by proactively disconnecting the voltage source from the DAC before heat can accumulate to levels that would affect light emission stability. The switch element enables the system to take preventive action by establishing a disconnected state during idle periods, counteracting the potential harmful thermal effects before they can manifest.
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 effectively prevents heat generation by the DAC during idle periods, ensuring consistent light emission properties and reducing power consumption in light-emitting devices.
Implementation Method 1
a digital-to-analog (D/A) converter configured to convert the digital signal into a voltage corresponding to the digital signal based on the reference voltage output from the voltage source
Implementation Method 2
a switch configured to switch, based on a control signal from the controller, a connection state between the voltage source and the D/A converter to a first state where the voltage source and the D/A converter are connected to each other and the voltage source supplies the reference voltage to the D/A converter, and a second state where an electrical connection between the voltage source and the D/A converter is disconnected
Implementation Method 3
a light-emitting portion configured to emit light for exposing a surface of the photosensitive drum based on supply of a driving current to the light-emitting portion according to an image signal
Data Source
AI summary
An image forming apparatus includes a light-emitting chip, a substrate on which a plurality of light emitting chips are mounted, a controller, and a switch. The light-emitting chip includes a light-emitting portion, which emits light exposing a photosensitive drum surface based on supply of a driving current to the light-emitting portion, and a driving portion that drives the light-emitting portion. The controller controls the driving portion by transmitting a signal to the light-emitting chip and outputs a digital signal corresponding to a target amount of light of the light-emitting portion to the light-emitting chip. Based on a control signal from the controller, the switch switches a connection state between the voltage source and the D/A converter to a first state where the voltage source supplies the reference voltage to the D/A converter, and a second state where an electrical connection between the voltage source and the D/A converter is disconnected.