Display Unit with Anisotropic Film and Wave Plate
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Solution Overview
Problem
Current display units with light transmissive films between liquid crystal display panels and light sources face challenges in improving luminance and view angle efficiency while maintaining low electrical power consumption and cost-effectiveness, as existing solutions either absorb too much light or require expensive reflective polarizers.
Innovation Solution
A display unit design incorporating a light transmissive film with refractive index anisotropy and a wave plate, where the light transmissive film has convex sections extending in one direction with a higher refractive index in that direction, and the wave plate adjusts polarization to minimize absorption and enhance light transmission through polarizers, allowing wider view angles and improved luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light transmissive film is provided between the liquid crystal display panel and the light source, then the display luminance is improved, but about half of the transmitted light is absorbed by the first polarizer, reducing light use efficiency
Solution Approach 1:
The patent introduces a wave plate to change the polarization state of light as a key parameter modification. By inserting a wave plate between the light transmissive film and the first polarizer, the polarization direction of light is adjusted to align with the polarizing axis of the first polarizer, thereby reducing absorption loss and improving light use efficiency while maintaining high display luminance
Solution Approach 2:
The wave plate serves as an intermediary optical element that mediates between the light transmissive film and the first polarizer. It transforms the polarization state of light emerging from the light transmissive film into a state that is compatible with the first polarizer's transmission axis, enabling efficient light transmission through the polarizer without requiring expensive reflective polarizers
2Loss of energy
If a reflective polarizer is used to improve light use efficiency, then the polarization component absorption is reduced, but the cost of the display unit becomes high
Solution Approach 1:
The patent replaces expensive reflective polarizers with a combination of a light transmissive film and a wave plate, which are cheaper optical elements. This substitution achieves similar light use efficiency improvement without the high cost associated with reflective polarizers, making the display unit more cost-effective while maintaining manufacturing simplicity
Solution Approach 2:
Instead of using a reflective polarizer that reflects unwanted polarization components, the patent uses a wave plate to actively change the polarization parameter of the light. This parameter transformation approach achieves efficient light utilization through a different physical mechanism that is more cost-effective than reflective polarizer technology
3Adaptability or versatility
If the polarizing axis of the second polarizer is arranged vertically to allow viewing with polarized sunglasses, then the view angle in the vertical direction is limited, but the horizontal view angle can be expanded
Solution Approach 1:
The light transmissive film with refractive index anisotropy changes the spatial distribution parameter of light transmission. By having different refractive indices in different directions, it preferentially transmits light in the horizontal direction while maintaining vertical polarization, thereby expanding the horizontal view angle without compromising compatibility with polarized sunglasses
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 display luminance and view angle efficiency, enabling wider horizontal view angles while maintaining low power consumption and cost-effectiveness by optimizing light transmission and absorption through the polarizers.
Implementation Method 1
The light transmissive film 133 has a plurality of prisms 133A in the shape of a triangle pole on the face (front face) on the light emitting side... out of light emitted from the linear light sources 131, the light mainly divergent in the vertical direction is raised in the direction orthogonal to the liquid crystal display panel 110 (front face direction) to be collect
Implementation Method 2
a wave plate provided between the first polarizer and the light transmissive film. The wave plate changes a polarization direction of light entering the wave plate so that an angle made by a polarization direction of a polarization component in the direction orthogonal to the one direction after passing through the wave plate among light passing through the light transmissive film and a polarizing axis direction of the first polarizer becomes small
Implementation Method 3
Of the light entering the first polarizer 120A, a polarization component in parallel with the polarizing axis a passes through the first polarizer 120A
Implementation Method 4
The light passing through the first polarizer 120A passes through the second polarizer 120B to the observer side according to a voltage size applied to each pixel by the not-shown drive circuit
Data Source
AI summary
A display unit in which the view angle in the horizontal direction of emitting light is wider than the view angle in the vertical direction thereof, in which the emitting light has a polarization component in the vertical direction viewable with the use of a polarized sunglass, and which is able to improve display luminance is provided. A luminance enhancement film has a plurality of convex sections which extend toward the horizontal direction and are arranged in the direction crossing the extending direction, and in which the refractive index in the extending direction is larger than the refractive index in the arrangement direction. A wave plate changes the polarization direction of light entering the wave plate so that an angle made by a polarization direction of the polarization component in the arrangement direction of the convex section after passing through the wave plate among light passing through the luminance enhancement film and the direction of a polarizing axis a of a first polarizer becomes small. A second polarizer has a polarizing axis b that transmits the polarization component in the vertical direction.