Phase Difference Compensation Element for Liquid Crystal Display
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Solution Overview
Problem
Existing phase difference compensation elements for liquid crystal display devices are costly, require extensive lamination, and have durability issues, leading to prolonged lead times and increased mounting space.
Innovation Solution
A phase difference compensation element featuring an optical anisotropic layer with birefringent films made of inorganic materials, where the film formation direction and thickness are aligned with the liquid crystal molecule orientation, combined with a phase difference providing antireflection layer, to improve contrast and durability while reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative C-plate is formed by laminating high-refractive-index thin films and low-refractive-index thin films alternately by vapor deposition, then structural birefringence is achieved to correct polarization disturbance, but a total number of 80 or more layers are required resulting in high cost and prolonged lead time
Solution Approach 1:
The patent changes the refractive index parameter by using a single high-refractive-index material (Ta2O5 with n=2.10) instead of alternating between high and low refractive index materials. This parameter change reduces the number of layers from 80 or more to just 3 layers while maintaining the structural birefringence needed for polarization correction
Solution Approach 2:
The patent extracts and eliminates the low-refractive-index layers from the alternating laminate structure, retaining only the high-refractive-index Ta2O5 layers. This extraction simplifies the structure from multiple alternating layers to a three-layer configuration with different optical path lengths, achieving the same polarization correction function with reduced complexity
2Reliability
If two phase difference plates formed of obliquely vapor-deposited film are used with rotation mechanism, then contrast is improved, but high cost and increase in mounting space occur
Solution Approach 1:
The patent merges the functions of two separate phase difference plates with a rotation mechanism into a single integrated compensation element. The three-layer obliquely vapor-deposited structure combines multiple optical functions (phase difference compensation and contrast improvement) in one component, eliminating the need for separate plates and rotation mechanisms, thus reducing mounting space while maintaining contrast improvement
Solution Approach 2:
The single compensation element with three obliquely vapor-deposited layers performs multiple functions simultaneously: it provides phase difference compensation for oblique incident light and improves contrast, replacing what previously required two separate phase difference plates and a rotation mechanism. This multi-functionality reduces both mounting space and system complexity
3Reliability
If phase difference compensation plate is formed by bonding two compensation layers, then optical compensation is achieved, but adhesive is required causing durability problems and two substrates are required raising cost
Solution Approach 1:
The patent uses a composite material approach by creating a multi-layer obliquely vapor-deposited structure where Ta2O5 layers with different optical path lengths are stacked. This composite structure achieves optical compensation through the inherent optical properties of the vapor-deposited layers themselves, eliminating the need for adhesive bonding and separate substrates, thereby improving durability and reducing cost
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
The solution enhances contrast and durability of liquid crystal display devices, reduces costs, and minimizes lead times by using fewer layers and eliminating the need for additional components like adhesives and substrates.
Implementation Method 1
an optical anisotropic layer including a plurality of birefringent films formed by deposited inorganic material
Implementation Method 2
the element including: a transparent substrate; and an optical anisotropic layer including a plurality of birefringent films
Implementation Method 3
each of the plurality of birefringent films is formed by deposited inorganic material
Implementation Method 4
disturbance of a polarization of an obliquely incident light to a light modulation element is corrected by a negative C-plate
Data Source
AI summary
Provided is a phase difference compensation element that can improve a contrast of a liquid crystal display device and has durability while suppressing an increase in cost and prolongation of lead time. The phase difference compensation element is formed so that, when an optical anisotropic layer is formed on a substrate, the optical anisotropic layer includes a plurality of birefringent films, and a direction of a combined vector obtained by combining respective vectors of the birefringent films when determining a vector with a direction of a line segment obtained by projecting a film formation direction of each birefringent film on a surface of a transparent substrate and a thickness, is substantially the same as a direction of a line segment obtained by projecting a liquid crystal molecule constituting a liquid crystal cell on the surface of the transparent substrate.