Electro-optical Device Segmented Capacitive Charging
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Solution Overview
Problem
Existing electro-optical devices with organic EL elements face challenges in achieving sufficient light emission due to limited capacitance, leading to large current generation and noise issues when charging and discharging multiple capacitative elements simultaneously.
Innovation Solution
The device employs a scanning line drive circuit and data line drive circuit to selectively charge and discharge capacitative elements in unit circuits, reducing the number of elements involved in simultaneous charging and discharging, and includes switching elements to control the flow of current, thereby minimizing large current generation and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If capacitative elements are used to accumulate charge for sufficient light emission, then light emission amount is improved, but physical area required becomes excessively large
Solution Approach 1:
The patent divides the pixel array into multiple banks (e.g., four banks), with each bank containing a subset of capacitative elements. Instead of charging all N capacitative elements simultaneously, the system charges only the capacitative elements within the currently selected bank during each frame period. This segmentation allows the light emission amount to be sufficient while keeping the physical area of individual capacitative elements within acceptable limits, as each element only needs to support a portion of the total pixel count rather than the entire array.
2Illumination intensity
If multiple capacitative elements are charged and discharged simultaneously, then light emission is achieved, but large current is generated instantaneously
Solution Approach 1:
The patent segments the capacitative elements into multiple banks and charges/discharges only the elements within the currently active bank simultaneously. This reduces the number of elements undergoing simultaneous charge/discharge operations from N (total elements) to N/4 or N/ bank (elements per bank), thereby reducing the instantaneous current magnitude while still achieving sufficient light emission through sequential bank activation.
Solution Approach 2:
The patent implements periodic charging and discharging of capacitative elements in different banks across successive frame periods. Each bank is activated in sequence, with capacitative elements charged during one frame period and discharged during the next. This periodic action distributes the current load over time, preventing large instantaneous current surges while maintaining continuous light emission across the entire pixel array.
3Quantity of substance
If large current is generated for charging/discharging capacitative elements, then charge accumulation is achieved, but noise is generated affecting control
Solution Approach 1:
By segmenting capacitative elements into multiple banks and charging/discharging only a subset in each frame period, the patent reduces the instantaneous current magnitude. This segmentation approach achieves the necessary charge accumulation for sufficient light emission while minimizing the generation of noise that would otherwise result from charging all N capacitative elements simultaneously, thereby improving control precision.
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 reduces the risk of large current generation and noise, allowing for more efficient and stable operation of the electro-optical device, enabling higher-quality image display with reduced noise and improved operational control.
Implementation Method 1
capacitative elements, each included in respective drive circuit (unit circuit), are used for driving one organic EL element
Implementation Method 2
a switching element that is disposed between the second electrode and the electric optical element and, by being electrically conducted in selecting one of the wirings by the scanning line drive circuit, allows the second electrode and the electric optical element to be electrically conducted
Implementation Method 3
an electro-optical device including organic EL (electro luminescent) elements
Data Source
AI summary
An electro-optical device includes: a plurality of unit circuits arranged corresponding to crossings between a plurality of scanning lines and a plurality of data lines; a plurality of wirings that constitutes each of the plurality of scanning lines; a scanning line drive circuit that sequentially selects one of the scanning lines while sequentially selecting one of the wirings included in the scanning line, at every driving period within each unit circuit; and a data line drive circuit that, at every period within the each unit period which is a writing period before the drive period is started, outputs a data potential in response to the gradation data of the unit circuit, which corresponds to the wiring selected in the driving period within the unit period, to a data line corresponding to the unit circuit out of the each data line. Each of the plurality of unit circuits includes: an electric optical element that displays gradation in response to the data potential; a capacitative element having a first electrode connected to a capacitance line and a second electrode connected to the data line; and a switching element that is disposed between the second electrode and the electric optical element and, by being electrically conducted in selecting one of the wirings by the scanning line drive circuit, allows the second electrode and the electric optical element to be electrically conducted.