Capacitive Touch Sensor Substrate with Phase Difference Film

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Solution Overview

Problem

Conventional display devices with capacitive touch panels face challenges in reducing thickness and weight, particularly when incorporating additional components like phase difference films and quarter wavelength plates, which increase the thickness between the display panel and the cover glass layer, and also struggle with visibility issues when used with polarized sunglasses.

Innovation Solution

The solution involves forming conductive layers on optical members such as phase difference films or circularly polarizing plates, eliminating the need for transparent base plates and simplifying the touch sensor structure, allowing for a thinner design while maintaining operability through polarized sunglasses by using substrates with optical films that impart specific phase differences and angle alignments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If two transparent base plates with conductive layers are used to form a capacitive touch sensor, then the touch sensor function is achieved, but the thickness between the display panel and cover glass layer increases

Engineering Contradiction:

Improvetouch sensor functionVSAvoidthickness between display panel and cover glass layer

Core Design Contradiction:

Ease of operationVSLength of stationary object

Solution Approach 1:

The patent merges the function of transparent base plates with the existing substrate by forming conductive layers directly on the substrate surfaces. This eliminates the need for separate transparent base plates while maintaining the capacitive touch sensor function, thereby reducing the overall thickness of the display device.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The substrate is given multiple functions: it serves as both the structural support for the display panel and as the base for forming the capacitive touch sensor conductive layers. This multi-functionality eliminates the need for additional dedicated components, reducing thickness.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple optical films and plates are added to enable operation through polarized sunglasses and prevent light reflection, then the functionality is improved, but the thickness and weight increase

Engineering Contradiction:

Improveoperation through polarized sunglassesVSAvoidthickness

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The patent combines the quarter wavelength plate and polarizing plate into a single integrated circularly polarizing plate component. This merging reduces the number of separate optical films and plates needed, thereby reducing overall thickness while maintaining the functionality to operate through polarized sunglasses and prevent light reflection.

Inventive Principle:

Principle #5Merging (Combining)

3Ease of operation

If multiple transparent base plates are used in the capacitive touch sensor structure, then the touch sensitivity is improved, but the weight of the display device increases

Engineering Contradiction:

Improvetouch sensitivityVSAvoidweight of display device

Core Design Contradiction:

Ease of operationVSWeight of stationary object

Solution Approach 1:

The patent merges the structural support function and touch sensor conductive layer formation into the single substrate component. This eliminates multiple transparent base plates, reducing the overall weight of the display device while maintaining touch sensitivity through the capacitive sensor formed on the substrate.

Inventive Principle:

Principle #5Merging (Combining)

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 overall thickness of the display device, enhances visibility by converting linearly polarized light to circularly polarized light, and prevents reflected light from interfering with content recognition, all while maintaining touch sensor functionality.

Implementation Method 1

the substrate has an optical film with a phase difference of (2n−1)λ/4, where n is a positive integer

Methodology Applied

Scientific EffectPhase difference: Birefringence

Implementation Method 2

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°

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 3

capacitive type, which detects input coordinates by monitoring changes in the electrostatic capacity between a finger tip and a conductive layer

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS10175831B2Display device with a capacitive touch panel

Publication Date: 2019.01.08 ZEON CORP

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 second conductive layer, and a substrate, in which 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 the stacking direction.