Display Driver Sensing Frequency Coordination
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Solution Overview
Problem
Display devices experience noise interference between the display panel and the input sensing layer, particularly when the input sensing layer is driven in response to external inputs while the display panel is operating, leading to reduced performance and increased power consumption.
Innovation Solution
The implementation of a display device with a display panel that operates at multiple driving frequencies, where the input sensing layer is driven only during specific periods when the display panel is at a lower frequency, thereby reducing noise interference by controlling the driving signals and frequencies to minimize unnecessary power usage and noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the input sensing layer is driven continuously while the display panel operates, then the input sensing function is maintained, but noise interference occurs between the display panel and the input sensing layer
Solution Approach 1:
The input sensing layer is driven periodically during specific periods (second period) when the display panel is in a lower frequency state, rather than continuously. This periodic driving approach maintains the input sensing function while avoiding noise interference during the display panel's high-frequency operation in the first period.
Solution Approach 2:
The driving frequency of the display panel is dynamically adjusted between a first driving frequency (higher) and a second driving frequency (lower). The sensing driver responds to these frequency changes by activating the input sensing layer only during the lower frequency period, creating a dynamic coordination between display operation and sensing function.
2Productivity
If the display panel operates at high driving frequency, then the display performance is improved, but power consumption increases
Solution Approach 1:
The display panel operates at high frequency during the first period and switches to lower frequency during the second period. This periodic frequency adjustment maintains display performance during critical periods while reducing power consumption during stable periods when the input sensing layer needs to be activated.
Solution Approach 2:
The driving frequency parameter of the display panel is changed between two distinct frequency levels. The sensing driver utilizes these parameter changes to determine when to activate the input sensing layer, optimizing both performance and power consumption by aligning sensing operation with lower-power display periods.
3Productivity
If the display panel drives at high frequency throughout, then the image refresh rate is maintained, but the input sensing layer cannot be driven without causing noise
Solution Approach 1:
Each frame is segmented into a first period and a second period with different driving frequencies. The input sensing layer is driven only during the second period when the display panel operates at lower frequency, allowing both image refresh and input sensing functions to coexist without noise interference.
Solution Approach 2:
The display panel alternates between high-frequency operation in the first period and low-frequency operation in the second period. This periodic frequency switching creates time slots where the input sensing layer can be activated without interfering with the display panel's high-frequency image refresh operation.
Data Source
AI summary
A display device includes a display panel that displays an image, an input sensing layer disposed on the display panel and that senses an input applied thereto from outside of the display device, a display driver that receives an image signal and drives the display panel at a first driving frequency or a second driving frequency lower than the first driving frequency, and a sensing driver that drives the input sensing layer. The display panel displays the image in a plurality of frames, each including a first period and/or a second period. The sensing driver drives the input sensing layer in the first period of each of the frames when the display panel is driven at the first driving frequency, and drives the input sensing layer in the second period of each of the frames when the display panel is driven at the second driving frequency.