Fluorescent Screen Polarizing Layer Blue Light Extraction
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Solution Overview
Problem
Existing fluorescent screen display devices suffer from low light utilization efficiency due to blue diffused light being transmitted through the reflection layer instead of being reflected back to contribute to image formation, leading to decreased luminance and contrast ratio depending on the viewing angle.
Innovation Solution
Incorporating a polarizing layer on the diffusion regions that transmits first linearly polarized light and reflects second linearly polarized light, along with a phase difference layer and a dielectric multilayer film reflecting layer, to enhance the light extraction efficiency by directing diffused light towards the front surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a reflection layer is provided on the rear surface to reflect red and green fluorescent light, then the light utilization efficiency of fluorescent light is increased, but the blue diffused light transmitted through the reflection layer does not contribute to image formation, decreasing the light utilization efficiency of blue light
Solution Approach 1:
The reflection layer is segmented into two functional parts: a wavelength-selective reflection layer for reflecting red and green fluorescent light, and a separate blue light reflection layer positioned at the diffusion region. This segmentation allows each layer to handle specific wavelengths independently, solving the contradiction by ensuring both fluorescent light and blue diffused light are effectively utilized without requiring a single complex multi-functional layer.
Solution Approach 2:
A blue light reflection layer is introduced as an intermediary component at the diffusion region. This intermediate layer specifically reflects blue light back toward the front surface, preventing its loss through transmission. The intermediary blue light reflection layer works in conjunction with the existing wavelength-selective reflection layer, enabling simultaneous optimization for both fluorescent light and blue light utilization efficiency.
2Adaptability or versatility
If isotropic diffusion is configured in all regions to increase spatial angular distribution, then the view angle dependency problem is solved, but diffused light is exited in both front and rear directions, decreasing light utilization efficiency
Solution Approach 1:
The diffusion characteristics are made local rather than uniform: the diffusion region maintains isotropic diffusion for wide viewing angle, while the phosphor regions use anisotropic diffusion to direct light primarily toward the front surface. This local differentiation allows each region to optimize its diffusion behavior according to its specific function, simultaneously achieving wide view angle and high light utilization efficiency.
Solution Approach 2:
Instead of attempting to control the diffusion direction in the phosphor regions to achieve both wide view angle and high efficiency, the invention inverts the approach by accepting the isotropic diffusion in phosphor regions and using the wavelength-selective reflection layer to redirect the light. The reflection layer acts as the controlling element to direct light toward the front surface, while the diffusion regions maintain their isotropic characteristics for viewing angle independence.
3Loss of energy
If blue light reflection layer is provided at diffusion region to reflect blue light, then the light utilization efficiency of blue light is increased, but the device structure becomes more complex
Solution Approach 1:
The blue light reflection layer is merged with the diffusion region structure, forming an integrated component rather than a separate external layer. This merging approach allows the blue light reflection functionality to be incorporated into the existing device architecture at the diffusion region, minimizing additional structural complexity while achieving the desired light utilization efficiency improvement.
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 increases the light extraction efficiency to 75% from the front surface, enhancing the luminance of blue diffused light by approximately 1.5 times compared to devices without these layers, allowing for higher luminance images with improved contrast ratio across viewing angles.
Implementation Method 1
a polarizing layer that is arranged on the side of the diffusion regions into which the first linearly polarized light is irradiated; wherein the polarizing layer transmits the first linearly polarized light and reflects second linearly polarized light whose vibrational direction differs from that of the first linearly polarized light
Implementation Method 2
a phase difference layer that is arranged on the side of the diffusion regions into which the first linearly polarized light is irradiated; wherein the phase difference layer converts circularly polarized light to first linearly polarized light
Implementation Method 3
The reflection layer is a wavelength-selective reflection layer that is made up of, for example, a dielectric multilayer film. The red and green fluorescent light that is emitted toward the rear surface from the first and second fluorescent regions is reflected in the direction toward the front surface by the reflection layer
Implementation Method 4
phosphor regions that contain a fluorescent material that absorbs excited light to emit fluorescent light (visible light)
Data Source
AI summary
A fluorescent screen includes phosphor regions 1-R, 1-G, diffusion region 1-B and reflecting means 10 formed on a region that includes phosphor regions 1-R and 1-G and diffusion region 1-B. Reflecting means 10 includes fluorescent light reflecting layer 11, phase difference layer 12, and polarizing layer 13 deposited in that order. Fluorescent light reflecting layer 11 transmits excited light 4 and reflects fluorescent light from phosphor regions 1-R and 1-G. Polarizing layer 13 both transmits excited light 4 and, of diffused light of the excited light (4) that was entered from diffusion region 1_B through Phase difference layer 12, transmits TM polarized light and reflects TE polarized light.