Conductive Sheet for Touch Panel with Dual-Side Exposure

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Solution Overview

Problem

Conventional methods for producing projected capacitive touch panels fail to form different conductive patterns on each side of a transparent support, leading to increased RC time constants and distorted detection waveforms, limiting screen size and operation time.

Innovation Solution

A method involving simultaneous exposure and development of photosensitive materials on both sides of a transparent support, where the first and second photosensitive layers are selectively exposed and developed to form distinct patterns, preventing light from one side from reaching the other, thereby controlling image formation and reducing RC time constants.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the same photosensitive emulsion layer is exposed on both sides of the transparent support using conventional methods, then the exposure process is simple, but the same pattern is formed on both sides which cannot achieve the projected capacitive touch panel structure with different patterns

Engineering Contradiction:

Improveexposure process simplicityVSAvoidpattern differentiation capability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The photosensitive emulsion layer is divided into two separate layers: a first photosensitive emulsion layer on the first surface and a second photosensitive emulsion layer on the second surface. This segmentation allows each layer to be exposed with different patterns independently, enabling the formation of different conductive patterns on each side of the transparent support while maintaining a relatively simple overall process structure.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If different patterns are exposed on both sides simultaneously, then pattern differentiation is achieved, but light from one side reaches the other side causing interference and incorrect pattern formation

Engineering Contradiction:

Improvepattern differentiation capabilityVSAvoidpattern formation accuracy

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The transparent support acts as an intermediary that physically separates the first photosensitive emulsion layer from the second photosensitive emulsion layer. This separation prevents light from the first exposure side from reaching the second photosensitive layer and vice versa, eliminating interference between the two exposure processes while still allowing both patterns to be formed on the same support structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional exposure methods are used, then the process is straightforward, but RC time constants increase and detection waveforms become distorted, limiting screen size and operation time

Engineering Contradiction:

Improveprocess straightforwardnessVSAvoiddetection waveform accuracy

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The first and second photosensitive emulsion layers are exposed with different patterns locally adapted to their respective positions on the transparent support. The first conductive pattern and second conductive pattern are designed with different configurations optimized for their locations, which reduces the RC time constants and prevents waveform distortion, thereby improving detection accuracy while maintaining process simplicity.

Inventive Principle:

Principle #3Local quality

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

Enables the formation of conductive sheets with reduced RC time constants, allowing for larger screen sizes and faster position detection within predetermined operation times.

Implementation Method 1

a first photosensitive layer formed on one main surface of the transparent support, and a second photosensitive layer formed on the other main surface of the transparent support... a first exposure treatment for irradiating the first photosensitive layer... and a second exposure treatment for irradiating the second photosensitive layer

Methodology Applied

Scientific EffectPhotosensitivity: Photography

Data Source

PatentUS8722314B2Method for producing conductive sheet and method for producing touch panel

Publication Date: 2014.05.13 FUJIFILM CORP

AI summary

A first exposure treatment for irradiating a first photosensitive layer formed on one main surface of a transparent support with a first light thereby to expose the first photosensitive layer and a second exposure treatment for irradiating a second photosensitive layer formed on the other main surface of the transparent support with a second light to expose the second photosensitive layer are performed such that the first light incident on the first photosensitive layer does not substantially reach the second photosensitive layer and the second light incident on the second photosensitive layer does not substantially reach the first photosensitive layer.