Liquid Crystal Display Data Transfer EMI Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In liquid crystal display devices, high-speed data transfer between semiconductor integrated circuits is hindered by increased wiring resistance and electromagnetic interference (EMI) noise, particularly as the number of pixels and clock frequency rise, leading to reduced setup/hold margins and high current consumption.
Innovation Solution
A data transfer method using a differential signal between the first semiconductor integrated circuit and the initial-stage second integrated circuit, followed by a CMOS signal with a long cycle and large amplitude between subsequent integrated circuits, reducing EMI and current consumption while maintaining adequate setup/hold margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a CMOS interface is used for data transfer between semiconductor integrated circuits, then the signal amplitude is sufficient, but the number of wires increases when parallel transmission is adopted to prevent EMI noise
Solution Approach 1:
The patent introduces a differential signal transmission system as an intermediary between the controller and data drivers. Instead of using traditional CMOS parallel transmission that requires multiple wires, the invention uses differential signaling (such as RSDS interface) that can transmit data serially with fewer wires while maintaining noise immunity through the differential nature of the signals
Solution Approach 2:
The patent replaces the mechanical/electrical CMOS parallel transmission system with an optical/electromagnetic differential signal transmission system. This substitution allows data to be transmitted more efficiently with reduced EMI noise and fewer physical connections required
2Object-affected harmful factors
If an RSDS interface is used to reduce EMI noise, then EMI is reduced, but the wiring resistance between data drivers increases due to long wiring length on glass substrate
Solution Approach 1:
The patent segments the data transmission path into two distinct sections: (1) from controller to initial-stage data driver using RSDS differential signaling for EMI reduction, and (2) between cascade-connected data drivers using CMOS parallel transmission for reliable data capture. This segmentation allows each section to use the optimal transmission method for its specific requirements
Solution Approach 2:
The patent applies different signal transmission qualities to different parts of the system. The first section (controller to initial data driver) uses high-speed differential signaling appropriate for long external connections, while the second section (between data drivers) uses robust CMOS signaling appropriate for the specific electrical characteristics of the glass substrate wiring
3Object-affected harmful factors
If an RSDS interface is used for data transfer between data drivers, then EMI noise is reduced, but current consumption increases due to fixed current requirement
Solution Approach 1:
The patent segments the data transmission system to apply RSDS interface only where necessary (from controller to initial-stage data driver for EMI reduction), while using lower-power CMOS interface for inter-data-driver communication, thus optimizing the balance between noise reduction and power consumption
Solution Approach 2:
The patent applies the low-power CMOS transmission method partially - only for the inter-data-driver connections where EMI is less of a concern but power consumption is critical, rather than applying it universally throughout the entire transmission path
4Measurement precision
If clock frequency is increased to support higher pixel density, then image detail and size improve, but wiring resistance and EMI noise increase leading to reduced setup/hold margin
Solution Approach 1:
The patent segments the transmission path to handle high-frequency signals differently at different stages, allowing high clock frequencies to be used for image detail while maintaining reliable data capture through appropriate interface selection at each segment
Solution Approach 2:
The patent changes the signal transmission parameters (interface type, signal level, transmission mode) based on the specific requirements of each transmission segment, enabling high clock frequencies to be used without compromising setup/hold margins
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 effectively reduces EMI and current consumption while ensuring accurate data capture by providing sufficient timing margins, even with increased wiring resistance, in high-frequency data transfers within liquid crystal display modules.
Implementation Method 1
the data is transferred between the first semiconductor integrated circuit and the initial-stage second semiconductor integrated circuit by means of a differential signal
Implementation Method 2
the data is transferred between each of the second semiconductor integrated circuits by means of a CMOS signal
Data Source
AI summary
The present invention provides a liquid-crystal display device that is able to reduce EMI, current consumption, and so forth in an interchip transfer of display data, a timing signal, and so forth and to provide an appropriate timing margin. In an interchip transfer of display data, a timing signal, and so forth that uses a plurality of data drivers, a certain data driver is used as a data driver. When the data driver is used in a first stage, an internal receiver is made to function as an RSDS receiver by fixing the IFM terminal at the “H” level. The received RSDS signal constitutes a CMOS signal that has been divided into two by the receiver and is output by the transmitter. Here, a data inversion signal is generated and output by the transmitter. When the data driver is used in the second or subsequent stage, the internal receiver is made to function as a CMOS receiver by fixing the IFM terminal at the “L” level. The received CMOS signal is output after being subjected to inversion control by means of the data inversion signal by the receiver and transmitter.