Tilted Optical Compensation Units for VA Display Phase Shift
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Solution Overview
Problem
In liquid crystal display apparatuses using vertical alignment (VA) panels, the pre-tilt of liquid crystals leads to phase shifts in light, causing light leakage and reduced contrast, and existing optical compensating plates require significant tilt angles, resulting in an oversized optical system.
Innovation Solution
A configuration that includes a first optical compensation unit with a small refractive index medium tilted in the same direction as the liquid crystal panel, combined with a second optical compensation unit having in-plane refractive index anisotropy, arranged to compensate for incomplete phase shifts, allowing for reduced tilt angles and a more compact optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single optical compensating plate is used to compensate for phase shift in VA liquid crystal panel, then phase compensation can be achieved, but the optical system becomes oversized due to the need for large tilt angle
Solution Approach 1:
The single optical compensating plate is divided into two separate compensating plates with different functions. The first compensating plate has a small tilt angle (0-15 degrees) and provides primary phase compensation, while the second compensating plate has a large tilt angle (45-60 degrees) and provides additional phase compensation. This segmentation allows each plate to operate at optimal tilt angles, reducing the overall optical system size while maintaining effective phase compensation.
Solution Approach 2:
The invention introduces a new dimension to the optical compensation approach by adding a second compensating plate with a different tilt orientation. Instead of relying on a single plate with large tilt angle, the system uses two plates with complementary tilt angles, effectively distributing the compensation function across multiple dimensional parameters (tilt angle, plate orientation) to achieve compact system design.
2Reliability
If optical compensating plate is arranged at large tilt angle to compensate for phase shift, then contrast is improved, but arrangement space requirement increases
Solution Approach 1:
The arrangement space requirement is segmented between two compensating plates. The first plate with small tilt angle requires minimal arrangement space, while the second plate with large tilt angle is positioned at a different location in the optical path. This segmentation of space requirements allows the system to achieve high contrast performance without requiring a single large arrangement space.
3Volume of stationary object
If tilt angle of optical compensating plate is reduced to downsize optical system, then optical system size is reduced, but phase compensation effectiveness deteriorates
Solution Approach 1:
The invention merges the compensation functions of two separate optical compensating plates to achieve the total phase compensation effectiveness that would otherwise require a single plate with large tilt angle. The first plate with small tilt angle and the second plate with large tilt angle work together in combination, their effects adding up to provide complete phase compensation while maintaining compact system size.
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 phase compensation, improves contrast, and downsizes the optical system by minimizing the tilt angle of the first optical compensating plate while maintaining effective phase shift compensation.
Implementation Method 1
a first optical compensation unit (first optical compensating plate 21) including a medium having a small refractive index in the thickness direction
Implementation Method 2
a second optical compensation unit (second optical compensating plate 22) having refractive index aeolotropy at least in an in-plane direction
Data Source
AI summary
An optical system is downsized by reducing a tilt angle of an optical compensating plate including a medium having a small refractive index in the thickness direction, in achieving a predetermined contrast.A liquid crystal display apparatus according to the present technology includes a vertical alignment liquid crystal panel, a first optical compensation unit including a medium having a small refractive index in a thickness direction, and being arranged with being tilted from a state parallel to the liquid crystal panel, at a position at which light having passed through the liquid crystal panel or not having passed through the liquid crystal panel enters, and a second optical compensation unit having refractive index aeolotropy at least in an in-plane direction, and being arranged at a position at which light having passed through the liquid crystal panel or not having passed through the liquid crystal panel enters.