Electro-Optical Device Noise Reduction via Pre-Charge Timing
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Solution Overview
Problem
Existing electro-optical devices face display unevenness due to noise in capacitance lines caused by voltage changes in data lines, leading to inaccurate gray scale representation when video or pre-charge voltage is supplied.
Innovation Solution
The electro-optical device incorporates a plurality of scan lines, signal lines, a reference line, and a control circuit that adjusts the supply periods for image signals and pre-charge signals to minimize noise in capacitance lines by extending the first and last supply periods of image signals to be longer than other periods, and synchronizing pre-charge periods with image signal supply periods to counteract potential fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-charge voltage or video voltage is supplied to data lines, then the pixel can be charged to the required voltage level, but noise is propagated to the capacitance line via coupling capacitance, causing display unevenness
Solution Approach 1:
The patent applies preliminary action by pre-charging data lines to a prescribed voltage level before supplying the video voltage. This prevents insufficient write of the video voltage to each pixel while managing the timing of voltage supply to reduce noise propagation to capacitance lines.
Solution Approach 2:
The patent employs periodic action by dividing data lines into blocks and alternately applying image signals to one block while applying pre-charge signals to another block. This periodic switching reduces continuous noise propagation and allows for controlled voltage supply cycles that minimize coupling capacitance interference.
2Stability of the object's composition
If the supply period for image signal is extended to reduce noise, then the stability of capacitance line potential is improved, but the horizontal scanning period may be exceeded
Solution Approach 1:
The patent segments the data lines into multiple blocks and processes them in alternating cycles. This allows the image signal supply period for each block to be extended without exceeding the overall horizontal scanning period, as other blocks are being pre-charged simultaneously. The segmentation enables parallel processing that maintains timing constraints while achieving stable capacitance line potential.
Solution Approach 2:
The patent performs preliminary pre-charging of data lines before supplying the image signal. This preliminary action reduces the required duration of the image signal supply period needed to achieve stable capacitance line potential, as the data lines are already charged to the appropriate voltage level, thereby fitting within the horizontal scanning 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
This solution effectively stabilizes the potential of capacitance lines, ensuring accurate gray scale representation and reducing display unevenness by canceling out noise through the counter noise effect, thereby enhancing the display quality.
Implementation Method 1
a pixel that is disposed corresponding to each of intersections between the plurality of scan lines and the k signal lines and that includes a holding capacitor coupled to the reference line, the pixel holding, in the holding capacitor, a potential corresponding to an image signal
Implementation Method 2
a change in voltage level of the data line is propagated to the capacitance line via a coupling capacitance between the data line and the capacitance line
Data Source
AI summary
An electro-optical device includes a plurality of scan lines, k signal lines, a pixel that is disposed corresponding to each of intersections between the plurality of scan lines and the k signal lines, an image signal circuit configured to sequentially supply the image signal to each of the k signal lines in a horizontal scanning period, a pre-charge circuit configured to supply, in the horizontal scanning period and in a prescribed order, a pre-charge signal to a signal line of the k signal lines to which the image signal circuit has not supplied the image signal yet; and a control circuit configured to set a first supply period of the k supply periods, during which the image signal is sequentially supplied to each of the k signal lines, to be longer than prescribed supply periods excluding the first supply period of the k supply periods.