Microlens Array Substrate Edge Slope Design for Liquid Crystal Displays
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Solution Overview
Problem
The existing microlens array substrates for liquid crystal devices suffer from inefficient light utilization due to excessive refraction at the edge portions of the microlens, leading to light blocking and reduced contrast, as the angle between the edge portion and the substrate surface is nearly 90 degrees, causing significant light loss and variation in light orientation.
Innovation Solution
The microlens array substrate is designed with a concave portion having a flat center portion, a curved surface portion, and an inclined edge portion, where the angle between the edge portion and the substrate is smaller than the angle formed by extending the curved surface, reducing excessive refraction and ensuring consistent light refraction across the edge portion, thereby improving light utilization efficiency and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the edge portion of the microlens is formed almost spherically with a 90-degree angle to the substrate surface, then the microlens can be formed by simple isotropic etching processing, but excessive refraction occurs at the edge portion causing light to be blocked by the light blocking layer
Solution Approach 1:
The microlens edge portion is segmented into multiple regions with different functions: a first edge portion with a gentle slope angle (30-60 degrees) that allows light to pass through without excessive refraction, and a second edge portion with a steeper slope angle (60-80 degrees) that provides the necessary optical focusing. This segmentation resolves the contradiction by combining the ease of manufacturing (through controlled etching) with improved light utilization efficiency (by preventing light blocking).
Solution Approach 2:
Different regions of the microlens edge portion are given different local qualities in terms of slope angle. The first edge portion has a gentler slope to reduce refraction and allow light passage, while the second edge portion has a steeper slope for optical focusing. This local differentiation resolves the contradiction between manufacturing simplicity and light utilization efficiency by optimizing each region for its specific function.
2Device complexity
If the edge portion of the microlens is formed almost spherically, then the manufacturing process is simplified, but the angle of light refracted at the edge portion becomes too large causing deterioration of contrast
Solution Approach 1:
The edge portion is divided into two segments with different slope angles. The first segment (30-60 degrees) controls light refraction to prevent contrast deterioration, while the second segment (60-80 degrees) maintains optical focusing capability. This segmentation reduces device complexity compared to complex multi-step manufacturing while eliminating the harmful effect of excessive refraction.
Solution Approach 2:
The slope angle parameter of the edge portion is changed from a uniform 90-degree spherical shape to a differentiated structure with angles of 30-60 degrees and 60-80 degrees. This parameter change resolves the contradiction by controlling light refraction angles to prevent contrast deterioration while maintaining manufacturing feasibility through controlled etching processes.
3Ease of manufacture
If isotropic etching processing is performed to form the concave portion, then the manufacturing process is straightforward, but unnecessary substances accumulate on the substrate surface covering the concave portion and hindering etching liquid circulation
Solution Approach 1:
A slope-forming process is performed preliminarily before the main isotropic etching to create a gentle slope at the edge portion. This preliminary action prevents unnecessary substance accumulation by ensuring proper etching liquid circulation, thereby achieving both ease of manufacture and high manufacturing precision without requiring complex multi-step processes.
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 enhances light utilization efficiency by allowing more light to be directed into the pixel openings, resulting in a brighter and more uniform display with improved contrast, as the inclined edge portion reduces light blocking and variation in light orientation.
Implementation Method 1
a lens layer having a different refractive index from a refractive index of the substrate, which is provided on the first surface of the substrate to fill in the plurality of concave portions
Implementation Method 2
light blocked by a light blocking layer among light incident on the liquid crystal device is condensed by the microlens so as to make the light incident on an opening region of a pixel
Data Source
AI summary
A microlens array substrate includes a substrate having transparency and having a plurality of concave portions provided on a first surface to correspond to a plurality of pixels, and a lens layer having a different refractive index from a refractive index of the substrate, which is provided on the first surface of the substrate to fill in the plurality of concave portions, in which each of the plurality of concave portions has a flat portion arranged at the center portion, a curved surface portion arranged to surround the flat portion, an edge portion arranged to surround the curved surface portion and connected to the first surface of the substrate, and an angle between the edge portion and the first surface in a cross section passing through the center portion is smaller than an angle between a virtual curved surface obtained by extending the curved surface portion toward the first surface and the first surface.