Counter Substrate Overcoat Films for Front-Luminance Display Control
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Solution Overview
Problem
Existing display apparatuses face challenges in optimizing luminance in the front direction while minimizing oblique light, particularly in applications where a wide viewing angle is not required, such as in head-mounted displays and smartphones, where reducing oblique light is desirable to enhance other performance aspects.
Innovation Solution
The overcoat film on the counter substrate is composed of multiple films with different refractive indexes, specifically a low-refractive-index film and a high-refractive-index film, which are patterned to redirect oblique light towards the front direction, improving luminance in this direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single overcoat film is used on the counter substrate, then the structure is simple and manufacturing is easier, but the luminance in the front direction cannot be sufficiently enhanced
Solution Approach 1:
The overcoat film is divided into multiple films (first overcoat film and second overcoat film) with different refractive indexes. This segmentation allows each film to contribute differently to light control, with the first film having higher refractive index for better front direction luminance and the second film having lower refractive index for reduced oblique light, thereby resolving the contradiction between enhanced luminance and structural complexity.
Solution Approach 2:
The patent uses composite material structure by combining multiple films with different refractive indexes in the overcoat layer. This composite approach enables optimized optical performance where the high refractive index film enhances front direction luminance while the low refractive index film suppresses oblique light, achieving superior display performance without excessive complexity.
2Illumination intensity
If oblique light is allowed to pass through, then viewing angle is widened, but luminance in front direction is reduced and display performance deteriorates
Solution Approach 1:
Different regions of the overcoat film structure are assigned different refractive indexes to perform different functions. The first overcoat film with higher refractive index is positioned to enhance front direction luminance, while the second overcoat film with lower refractive index is positioned to suppress oblique light. This local quality differentiation resolves the contradiction by allowing selective control of light in different directions.
Solution Approach 2:
The patent changes the refractive index parameter across different films in the overcoat layer. By using films with different refractive indexes (first film: higher refractive index, second film: lower refractive index), the system optimizes light transmission characteristics to enhance front direction luminance while suppressing oblique light, thereby resolving the contradiction between these two optical requirements.
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 luminance in the front direction by redirecting oblique light, thereby improving display performance in applications where a narrow viewing angle is preferred.
Implementation Method 1
the overcoat film is made of a plurality of types of films having different refractive indexes
Data Source
AI summary
Performance of a display apparatus is improved. A display apparatus includes: an array substrate including a switching element; and a counter substrate facing the array substrate. In this case, the counter substrate includes: a substrate having a light transmitting property; and an overcoat film being in contact with the substrate, and the overcoat film is made of a plurality of types of films having different refractive indexes.