Adhesive Member Design for Force Sensing in LCD Backlight Units
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Solution Overview
Problem
Conventional liquid crystal display devices with force sensing capabilities face challenges in accurately sensing pressing forces due to limited variation in distance between electrodes, which restricts the range and accuracy of force sensing.
Innovation Solution
A liquid crystal display device configuration that includes a liquid crystal panel with substrates and electrodes, a backlight unit with optical members and a second electrode, and an adhesive member with a double-layer structure to securely attach the backlight to the panel, increasing the distance variation between electrodes and enhancing force sensing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional single-layer adhesive member is used to fix the backlight device to the liquid crystal panel, then the structure is simple and manufacturing is easy, but the distance variation between electrodes is limited which reduces force sensing accuracy
Solution Approach 1:
The adhesive member is divided into multiple layers (first adhesive layer, second adhesive layer, third adhesive layer) with different properties. Each layer serves a specific function: the first layer provides initial bonding, the second layer (with cushioning member) enables distance variation for force sensing, and the third layer provides final fixation. This segmentation resolves the contradiction by achieving both structural complexity and improved force sensing accuracy.
Solution Approach 2:
The adhesive member's thickness and material properties are changed by introducing a cushioning member in the second adhesive layer. This allows the distance between the first electrode portion and second electrode portion to vary dynamically in response to pressing forces, thereby improving force sensing accuracy while maintaining a manageable structural complexity through controlled parameter variations.
2Measurement precision
If the distance between electrodes is increased to improve force sensing range, then the sensing accuracy improves, but the overall device thickness increases
Solution Approach 1:
The cushioning member is strategically placed only in the second adhesive layer at specific locations where distance variation is needed for force sensing, rather than uniformly throughout the entire adhesive structure. This local quality approach allows the electrode distance to vary in the sensing region while keeping the overall device thickness controlled, resolving the contradiction between sensing accuracy and device compactness.
Solution Approach 2:
The adhesive member is designed to be dynamic rather than rigid. The cushioning member allows the distance between electrodes to change dynamically in response to applied pressing forces, enabling the system to achieve both increased sensing range and maintained device thickness through controlled dynamic adjustment rather than fixed static dimensions.
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 configuration widens the range of pressing force sensing and improves accuracy by increasing the electrostatic capacity variation, allowing for more precise detection of pressing forces and enhancing impulse absorption.
Implementation Method 1
an adhesive member between the liquid crystal panel and the backlight device to fix the backlight device to the liquid crystal panel. The adhesive member includes a first base, adhesive layers on both surfaces of the first base, a second base on the first base via one of the adhesive layers, and an adhesive layer on the second base
Implementation Method 2
A variation in distance between two electrodes provided in the liquid crystal display device is read as an electrostatic capacity variation, which is considered as capacitance-type input sensing for sensing the pressing force
Data Source
AI summary
A display device is provided and includes a liquid crystal panel comprising a pair of substrates, a liquid crystal layer between the substrates, a first electrode portion and a pair of polarizers that sandwich the substrates; a backlight device comprising a casing including a support frame, a bottom plate, a light guide, at least one optical sheet on the light guide, and a light source in the casing; and an adhesive member between the liquid crystal panel and the backlight device, wherein the support frame includes a step portion on which the optical sheet is placed, the adhesive member comprises a back surface fixed over the optical sheet and the support frame, and a top surface fixed to one of the polarizers, and a width of the adhesive member is as same as a width of the support frame.