Liquid Crystal Display Spacer Height Control via Photosensitive Material
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Solution Overview
Problem
In liquid crystal displays, forming spacers with desired step differences is challenging due to material limitations, leading to alignment errors and increased manufacturing costs, as existing photosensitive materials do not allow for sufficient height variation with cross-section width changes without changing masks.
Innovation Solution
The use of a colored photosensitive material with positive photosensitivity, which defines maximum height based on cross-section dimensions and reduces height for larger dimensions, allowing spacers of different heights to be formed without changing the mask, enabling precise step formation and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the same material is used for both main spacer and subspacer to maintain material consistency, then material uniformity is improved, but the ability to form desired step differences in height is worsened
Solution Approach 1:
The patent applies parameter changes by utilizing the photosensitive material's property where height varies with cross-section width dimension. By controlling the exposure amount of light during photolithography, different heights (main spacer and subspacer) are achieved from the same material without changing masks, thus maintaining material uniformity while achieving precise step differences.
Solution Approach 2:
The patent transitions from controlling height through vertical stacking to controlling height through cross-section width dimension. The photosensitive material's height is defined by its cross-section width dimension after exposure, allowing step differences to be formed in the horizontal dimension that translate to vertical height variations.
2Manufacturing precision
If different masks are changed to obtain desired step differences, then manufacturing precision is improved, but manufacturing cost is worsened
Solution Approach 1:
The patent makes a single mask serve multiple functions by utilizing the photosensitive material's characteristic where different exposure amounts produce different heights. One mask pattern can define both main spacers and subspacers with different heights through varying light exposure, eliminating the need for multiple masks and reducing manufacturing complexity.
Solution Approach 2:
The patent changes the exposure amount parameter during photolithography to achieve different spacer heights from the same mask. By controlling light exposure intensity and duration, the photosensitive material forms spacers with desired step differences without requiring physical mask changes, thereby reducing manufacturing cost while maintaining precision.
3Manufacturing precision
If a light blocking member is added to achieve precise alignment, then alignment precision is improved, but device complexity is worsened
Solution Approach 1:
The patent enables the photosensitive material to self-align and self-define its height based on its cross-section width dimension and exposure amount. The material inherently forms the desired spacer structure with precise alignment through the photolithography process without requiring additional light blocking members, thus achieving alignment precision while avoiding increased structural complexity.
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 allows for the formation of spacers with desired step differences using the same material, reducing manufacturing costs and improving alignment precision by varying spacer height based on exposure amount and cross-section dimensions, facilitating the production of liquid crystal displays with enhanced performance.
Implementation Method 1
The first spacer and the second spacer include a photosensitive material defining a maximum height of a spacer with respect to a predetermined a cross-section width dimension of the spacer, and defining heights less than the maximum height with respect to cross-section width dimensions larger than predetermined cross-section width dimension
Data Source
AI summary
A liquid crystal display includes a first substrate and a second substrate facing each other, a first spacer and a second spacer on the first substrate and have different heights, and a liquid crystal layer between the first substrate and the second substrate and including a plurality of a liquid crystal molecule. The first spacer and the second spacer include a photosensitive material defining a maximum height of a spacer with respect to a predetermined a cross-section width dimension of the spacer, and heights less than the maximum height with respect to cross-section width dimensions larger than the predetermined cross-section width dimension. The first spacer and the second spacer can include a black pigment.