Capacitive Touch Sensor Integrated with Optical Film for Thinner Displays
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Solution Overview
Problem
Conventional display devices with capacitive touch panels face challenges in reducing thickness and weight, particularly when additional components like phase difference films and polarizing plates are included, which increase the thickness between the liquid crystal or OLED panel and the cover glass layer.
Innovation Solution
The solution involves forming a capacitive touch sensor with two conductive layers and a dielectric layer on an optical member, such as a phase difference film or polarizing plate, eliminating the need for transparent base plates and simplifying the structure to reduce thickness, while maintaining operability through polarized sunglasses and minimizing light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional touch sensor unit with two transparent base plates is used, then the touch sensor can function properly, but the thickness between the liquid crystal panel and cover glass layer increases
Solution Approach 1:
The patent combines the touch sensor unit with the optical member (phase difference film or polarizing plate) by forming conductive layers directly on the optical member, eliminating the need for separate transparent base plates. This merging reduces the number of components and overall thickness while maintaining touch sensor functionality.
Solution Approach 2:
The patent extracts and eliminates the transparent base plates from the touch sensor unit structure. By forming conductive layers directly on the optical member surface, the unnecessary base plates are removed, reducing thickness and simplifying the overall structure.
2Adaptability or versatility
If additional optical components like phase difference films and polarizing plates are added, then viewing angle compensation and polarized sunglasses operability are achieved, but the thickness between panel and cover glass increases
Solution Approach 1:
The optical member serves multiple functions: it acts as both the phase difference film/polarizing plate for viewing angle compensation and polarized sunglasses operability, and simultaneously serves as the substrate for the touch sensor conductive layers. This multi-functionality eliminates the need for separate components, reducing overall thickness.
Solution Approach 2:
The patent merges the optical member with the touch sensor substrate by forming conductive layers directly on the optical member. This combination allows the optical components to fulfill both their optical functions and serve as the structural base for the touch sensor, reducing the number of separate layers and overall device thickness.
3Ease of manufacture
If conventional touch sensor structure with separate base plates is used, then manufacturing is straightforward, but the overall device thickness increases
Solution Approach 1:
The patent combines the touch sensor manufacturing process with the optical member manufacturing by forming conductive layers directly on the optical member surface. This integrated approach maintains ease of manufacture through standard coating techniques while eliminating the need for separate assembly of base plates, thereby reducing overall device thickness.
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 effectively reduces the thickness of the display device, allows operation through polarized sunglasses, and prevents reflected light from obstructing visual recognition of the displayed content, achieving a thinner and more functional design.
Implementation Method 1
the substrate has an optical film with a phase difference of (2n−1)λ/4... linearly polarized light traveling from the liquid crystal panel side through the viewing-side polarizing plate towards the cover glass layer side is converted by the quarter wavelength plate into circularly polarized light or elliptically polarized light
Implementation Method 2
capacitive type, which detects input coordinates by monitoring changes in the electrostatic capacity between a finger tip and a conductive layer
Data Source
AI summary
Disclosed is a display device with a capacitive touch panel including a laminate between a display panel and a cover layer, the laminate having a viewing-side polarizing plate; a first conductive layer, a dielectric layer and a second conductive layer constituting a capacitive touch sensor; and a substrate, in which the first conductive layer, dielectric layer, second conductive layer, and substrate are positioned closer to the cover layer than is the viewing-side polarizing plate, the first conductive layer is formed on one surface of the to substrate, the dielectric layer is formed on a surface of the first conductive layer opposite to the substrate side, the second conductive layer is formed on a surface of the dielectric layer opposite to the first conductive layer side, the substrate has an optical film with a phase difference of (2n−1)λ/4, where n is a positive integer, the viewing-side polarizing plate has a polarizing film, and a slow axis of the optical film intersects a transmission axis of the polarizing film at an angle of about 45° as viewed in a stacking direction.