Integrated Photo-Sensing Touch Panel in Electrophoretic Display
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Solution Overview
Problem
Conventional electrophoretic display (EPD) devices require separate formation and attachment of touch screen panels, increasing thickness, weight, and process complexity, while also deteriorating transmittance due to the overlapped structure.
Innovation Solution
An EPD device with a touch panel integrated into the display, featuring a photo-sensing unit formed on the substrate with gate lines, data lines, and transistors, where the photo-sensing circuit utilizes existing signal lines to minimize additional signal lines, thereby reducing thickness and weight, and improving transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a touch screen panel is separately formed and attached to the EPD device, then the touch input function is achieved, but the whole thickness and weight increase
Solution Approach 1:
The patent merges the touch panel and EPD device into a single integrated structure. The photo-sensing unit, sensing transistor, and electro-phoretic display elements are all formed on the same substrate, eliminating the need for separate attachment and reducing overall device weight.
Solution Approach 2:
The substrate serves multiple functions simultaneously: it acts as the base for both the EPD display elements and the touch panel photo-sensing units. The same substrate also houses the sensing transistors and signal lines, making it a multi-functional component that reduces overall device complexity and weight.
2Ease of operation
If a touch screen panel is separately attached to the EPD device, then the touch input function is achieved, but the number of processes increases
Solution Approach 1:
The patent combines the manufacturing processes for the touch panel and EPD device into a single integrated fabrication process. Both the photo-sensing units and display elements are formed on the same substrate through sequential deposition and patterning steps, eliminating the need for separate attachment processes.
Solution Approach 2:
The sensing transistors, photo-sensing units, and signal lines are all formed on the substrate before the electro-phoretic layer is deposited. This preliminary formation of all circuit components allows for a more efficient manufacturing process where the touch panel functionality is built-in during the same fabrication sequence as the display.
3Volume of moving object
If the touch screen panel and EPD device are overlapped, then the device structure is compact, but the transmittance deteriorates
Solution Approach 1:
The patent employs local quality by making the pixel electrodes and common electrodes transparent in specific regions where light needs to pass through to the photo-sensing units. This localized transparency allows the overlapped structure to maintain adequate transmittance while still achieving compact device volume.
Solution Approach 2:
The patent resolves the transmittance issue by utilizing the vertical dimension. The photo-sensing units are positioned on the same substrate as the electrodes, and light can pass through transparent electrode regions in the plane while the sensing functionality operates in the vertical dimension through the photo-sensing transistors, maintaining both compactness and transmittance.
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
The integration of a photo-sensing circuit within the EPD device allows for an in-cell type touch panel, reducing weight, simplifying processes, and maintaining high image quality by minimizing non-operational areas and signal line overlap.
Implementation Method 1
The EPD device applies voltage to the two facing electrodes so that a potential difference is caused between opposite ends of the electrodes, accordingly moving the black and white electrified pigment particles respectively to the electrodes having opposite polarities
Implementation Method 2
a photo-sensing unit which senses light and thereby generates a sensing signal
Data Source
AI summary
Disclosed is an electro phoretic display (EPD) device capable of minimizing the whole thickness and weight by integrally including a photo-sensing touch panel and minimizing the number of lines such as a signal line. The EPD device includes first and second substrates facing each other, a plurality of gate lines, a plurality of common lines, and a driving voltage line formed on the first substrate in a first direction, an output line formed and a plurality of data lines defining pixel regions by crossing the gate lines in a second direction, pixel transistors formed at intersecting parts between the respective gate lines and the data lines, a pixel electrode formed at each pixel region, a sensing transistor formed between one of the common lines and the driving voltage line, an output transistor formed between one of the gate lines, adjacent to the sensing transistor, and the sensing transistor to transmit an output signal to the output line, a sensing capacitor formed between one of the common lines and a connection part between the sensing transistor and the output transistor, a common electrode formed over the entire surface of the second substrate, and an electro phoretic layer formed between the first and the second substrates.