Display Apparatus Viewing Angle Control via Liquid Crystal Alignment
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Solution Overview
Problem
Conventional display apparatuses with wide viewing angles can inadvertently expose confidential information to others, and existing solutions like light control films and electrically-controlled diffusers reduce brightness and increase power consumption.
Innovation Solution
A display apparatus with an electrically-controlled viewing angle range, utilizing a configuration of liquid-crystal layers, alignment layers, polarizers, and a half-wave plate, along with optical brightness enhancement films, to switch between wide and narrow viewing angles while maintaining brightness and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a light control film and electrically-controlled diffuser are used to achieve narrow viewing angle mode, then anti-peep effect is improved, but overall brightness is reduced and power consumption increases
Solution Approach 1:
The patent changes the alignment angles of liquid crystal layers to control viewing angle. By adjusting the alignment directions of first and second liquid crystal layers with specific angle ranges (75-105 degrees and 165-195 degrees respectively), the display switches between wide and narrow viewing angle modes without requiring additional light control films, thereby maintaining brightness while achieving anti-peep effect
Solution Approach 2:
The patent extracts and removes the light control film from the display structure, replacing its function with electrically-controlled liquid crystal layers. This eliminates the brightness reduction and power consumption increase caused by the light control film while maintaining the narrow viewing angle capability through liquid crystal alignment control
2Object-affected harmful factors
If a light control film and electrically-controlled diffuser are used to achieve narrow viewing angle mode, then anti-peep effect is improved, but power consumption increases
Solution Approach 1:
The patent uses parameter changes in liquid crystal alignment angles to control viewing angle. By electrically adjusting the alignment directions of liquid crystal layers within specific angle ranges, the display achieves narrow viewing angle mode without power-consuming light control films, reducing overall power consumption while maintaining anti-peep effect
Solution Approach 2:
The patent removes the electrically-controlled diffuser and light control film components that consume additional power. The anti-peep function is achieved purely through liquid crystal alignment control, eliminating the extra power consumption associated with driving separate light control components
3Object-affected harmful factors
If viewing angle is reduced to achieve anti-peep effect, then confidential information protection is improved, but color shift increases in narrow viewing angle mode
Solution Approach 1:
The patent uses a composite structure of multiple liquid crystal layers with different alignment characteristics. The first liquid crystal layer (75-105 degrees) and second liquid crystal layer (165-195 degrees) work together to control viewing angle while compensating for color shift, achieving both anti-peep effect and color accuracy simultaneously
Solution Approach 2:
The patent applies different alignment angle characteristics to different liquid crystal layers. Each layer has optimized alignment angles tailored to its position and function, with the first layer providing base viewing angle control and the second layer fine-tuning the narrow angle mode while maintaining color accuracy through localized optimization
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 provides a better anti-peep effect in narrow viewing angle mode with minimal color shift and reduced power consumption, allowing for adjustable viewing angles to suit different usage scenarios.
Implementation Method 1
The first liquid-crystal layer is sandwiched between the first alignment layer and the second alignment layer. An included angle between a first alignment direction of the first alignment layer and a second alignment direction of the second alignment layer is greater than or equal to 75 degrees and less than or equal to 105 degrees. An included angle between a third alignment direction of the third alignment layer and a fourth alignment direction of the fourth alignment layer is greater than or equal to 165 degrees and less than or equal to 195 degrees.
Implementation Method 2
The first polarizer is provided between the backlight module and the first electrically-controlled element, and has a first absorption axis parallel or perpendicular to the first alignment direction. The second polarizer is provided between the first electrically-controlled element and the second electrically-controlled element, and has a second absorption axis. An axial direction of the second absorption axis is perpendicular to an axial direction of the first absorption axis.
Implementation Method 3
The half-wave plate is provided between the second polarizer and the second electrically-controlled element
Implementation Method 4
The first optical brightness enhancement film is disposed on a side of the light-emitting surface of the light guide plate, and has a plurality of first prism structures. An included angle between an extending direction of the first prism structures and a first viewing angle control direction of the display apparatus is less than 45 degrees. The second optical brightness enhancement film is disposed on a side of the first optical brightness enhancement film away from the light guide plate, and has a plurality of second prism structures.
Data Source
AI summary
A display apparatus including a backlight module, first and second electrically-controlled elements, electrically-controlled first and second polarizers, a half-wave plate, and a display panel is provided. An included angle between first and second alignment directions of first and second alignment layers of the first electrically-controlled element is between 75 degrees and 105 degrees. An included angle between third and fourth alignment directions of third and fourth alignment layers of the second electrically-controlled element is between 165 degrees and 195 degrees. The half-wave plate is disposed between the second polarizer and the second electrically-controlled element. The display panel is disposed on the second electrically-controlled element. An included angle between an extending direction of prism structures of each of two optical brightness enhancement films of the backlight module and a viewing angle control direction of the display apparatus is less than 45 degrees. A method of driving the display apparatus is provided.