Display Multiplexer Merges DACs to Reduce Driving Circuit Size
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Solution Overview
Problem
The increasing number of pixels in display devices leads to a larger data driving part, higher fabrication costs, and challenges in achieving flexible touch display devices due to additional driving parts.
Innovation Solution
A display device design that incorporates a multiplexer to reduce the number of digital analog converters, decrease the size and number of data driving parts, and lower fabrication costs, while also improving luminance uniformity, optimizing optical compensation, and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of pixels is increased to improve display resolution, then the display quality is improved, but the number of output terminals of the data driving part increases, causing the size and number of data driving parts to increase and fabrication cost to increase
Solution Approach 1:
The patent merges the functions of multiple output terminals into a single output terminal by using a multiplexer. The data driving part includes one digital-to-analog converter (DAC) that outputs a single data voltage, which is then sequentially switched to multiple data lines through the multiplexer. This allows multiple pixels to share a single output terminal, reducing the number of DACs and output terminals required while maintaining the ability to drive high-resolution displays.
Solution Approach 2:
The patent introduces dynamic switching of data lines through the multiplexer, which sequentially connects the single output terminal to different data lines at different time periods. This dynamic time-division multiplexing allows the system to adaptively allocate the single output terminal to different pixels based on the display refresh requirements, enabling high resolution without proportionally increasing the number of static output terminals.
2Adaptability or versatility
If additional touch driving part and display driving part are added to achieve touch display functionality, then the touch sensing capability is improved, but the volume of the touch display device increases and flexibility is reduced
Solution Approach 1:
The patent makes the data driving part universal by enabling it to perform both display driving functions and touch sensing functions through the same hardware infrastructure. The multiplexer and data lines are used for both transmitting display data during display periods and transmitting touch sensing signals during sensing periods. This multi-functionality eliminates the need for separate touch driving parts, reducing device volume while maintaining touch sensing capability.
Solution Approach 2:
The patent implements periodic switching between display mode and touch sensing mode using the same data driving circuitry. During first time periods, the multiplexer routes signals for display data transmission; during second time periods, it routes signals for touch sensing. This periodic time-division multiplexing allows a single data driving part to alternately perform both functions, reducing the need for additional dedicated touch driving hardware and thereby reducing overall device volume.
3Productivity
If multiple digital analog converters are used to drive multiple output terminals, then the data driving capability is improved, but the size and number of data driving parts increase
Solution Approach 1:
The patent combines multiple data driving functions into a single DAC by using a multiplexer. Instead of having separate DACs for each output terminal, one DAC generates a single data voltage that is then distributed to multiple data lines through the multiplexer's switching mechanism. This merging approach maintains full data driving capability while significantly reducing the area occupied by the data driving part, as one DAC occupies much less area than multiple DACs would require.
4Device complexity
If data voltage is supplied to subpixels in a conventional manner, then the data transmission is simplified, but luminance deviation occurs and deterioration such as vertical line stain appears
Solution Approach 1:
The patent applies dynamic control to the data transmission timing by using the multiplexer to sequentially supply data voltage to different subpixels at precisely controlled time periods. This dynamic time-division approach ensures that each subpixel receives its data voltage at the optimal moment in the display refresh cycle, preventing luminance deviation and vertical line stains while maintaining relatively simple data transmission circuitry. The sequential switching allows for precise timing control without requiring complex parallel transmission circuits.
Data Source
AI summary
A display device includes a timing controlling part generating an image data, a data control signal and a gate control signal; a data driving part generating a data voltage using the image data and the data control signal; a gate driving part generating a gate voltage using the gate control signal; a display panel including a plurality of subpixels and displaying an image using the data voltage and the gate voltage; and a plurality of first MUX switches and a plurality of second MUX switches sequentially transmitting the data voltage to two of a same color among the plurality of subpixels.