TN LCD Region Switching to Reduce Viewing-Angle Tint Shift
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Solution Overview
Problem
TN type liquid crystal display devices experience significant tint changes depending on the viewing angle due to varying transmission wavelength characteristics of the backlight, which complicates device configuration and control, especially when using multiple light sources and optical members.
Innovation Solution
A liquid crystal display device with a backlight source emitting light rays of two or more wavelengths, a Twisted Nematic type liquid crystal panel, and a processor that switches between modes to set larger areas as shielding or transmission regions based on the viewing conditions, minimizing tint changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a TN type liquid crystal display device uses a backlight with multiple wavelengths, then the display can operate at low voltage and be inexpensive, but the transmission wavelength characteristics vary with viewing angle causing significant tint changes
Solution Approach 1:
The patent changes the parameter of wavelength composition by introducing a wavelength conversion layer that converts blue light to green light. This modifies the spectral characteristics of the backlight to reduce wavelength-dependent tint changes while maintaining the low-voltage operation and cost-effectiveness of TN type liquid crystal displays.
Solution Approach 2:
The patent introduces a wavelength conversion layer as an intermediary component between the blue LED backlight and the liquid crystal panel. This intermediate layer converts the blue light to green light, acting as a mediator that reduces the harmful wavelength-dependent optical characteristics without requiring complex optical members or multiple light sources.
2Stability of the object's composition
If multiple light sources and optical members are used to suppress tint changes, then color consistency improves, but device configuration and control become complicated
Solution Approach 1:
The patent extracts and eliminates the need for complex optical members and multiple light sources by using a simple wavelength conversion layer. This removes the disturbing part (complex configuration) while maintaining the beneficial effect (color consistency) through a simpler approach.
Solution Approach 2:
The patent replaces expensive and complex optical members with a simple, inexpensive wavelength conversion layer. This disposable-like simple component achieves the same goal of suppressing tint changes without requiring sophisticated optical systems, reducing both cost and complexity.
3Stability of the object's composition
If the shielding region area is increased to reduce tint changes, then color consistency improves, but the display area for information is reduced
Solution Approach 1:
The patent changes the optical parameter of the backlight by introducing wavelength conversion, which reduces tint changes without requiring changes to the display region geometry. This allows the full display area to be utilized while maintaining color consistency, avoiding the trade-off between shielding region area and display area.
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 effectively reduces noticeable tint changes by adjusting the display regions based on viewing angles, simplifying the device configuration and control without additional optical members.
Implementation Method 1
a liquid crystal display panel which has a shielding region which shields the backlight and an external incidence ray and a transmission region which transmits the backlight using a Twisted Nematic type liquid crystal
Implementation Method 2
a light source of a backlight that includes light rays of two or more wavelengths
Data Source
AI summary
An electronic apparatus using a liquid crystal display device, a display control method used in the liquid crystal display device, and a non-transitory recording medium for storing a display control program, sets a region having a larger area of an information display region and a background region as a transmission region and a region having a smaller area as a shielding region. A tint change of the shielding region caused by a TN type liquid crystal and a light source for backlight is reduced, and thus, it is possible to make the tint change depending on the viewing direction unremarkable.