Polarized-light splitting device with reflective and absorptive ridges
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Solution Overview
Problem
Existing polarized-light splitting devices, such as dichroic polarizing films, have limited light use efficiency due to absorption of perpendicular polarized light, and there is a need for a simple and economical solution for large-scale manufacturing of polarized-light splitting devices for liquid crystal display devices in mobile phones, PDAs, and LCD TVs.
Innovation Solution
A polarized-light splitting device with a reflective and absorptive portion sequentially stacked, featuring a transmissive base member with a pattern of ridges and a non-transmissive layer comprising a light reflecting and light absorbing portion, where the reflectivity of the intermediate portion is between that of the reflective and absorptive portions, achieved through varying deposition angles and materials like metal and metal oxides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a dichroic polarizing film is used, then the device structure is simple, but light use efficiency is limited to not more than 50% because the film absorbs light polarized perpendicular to the transmission axis
Solution Approach 1:
The non-transmissive layer is segmented into distinct light reflecting portion and light absorbing portion, each performing separate functions. The reflecting portion reflects non-transmitted polarized light back to the backlight unit, while the absorbing portion absorbs remaining light, thereby improving light use efficiency without requiring a complex multi-component structure
Solution Approach 2:
Different regions of the non-transmissive layer are assigned different optical properties: the light reflecting portion has high reflectivity for non-transmitted polarized light, while the light absorbing portion has high absorptivity. This local differentiation of properties enables the system to achieve both high light use efficiency and relatively simple structure
2Loss of energy
If a wire grid type polarized-light splitting device with conductive material ridges is used, then light use efficiency is improved by reflecting non-transmitted light back, but manufacturing complexity increases for large-size production
Solution Approach 1:
The patent combines the light reflecting function and light absorbing function into a single non-transmissive layer, eliminating the need for separate wire grid structures with conductive materials. This merging of functions simplifies the manufacturing process for large-size production while maintaining the light use efficiency benefits of reflection
Solution Approach 2:
The non-transmissive layer uses cost-effective materials (metal and metal oxide) that can be deposited using standard coating techniques, replacing expensive and complex wire grid structures. The layer is designed to be a simple coating rather than a complex three-dimensional wire structure, facilitating economical large-scale manufacturing
3Reliability
If only reflective and absorptive portions are stacked without intermediate portion, then the structure is simple, but optical performance and contrast may be compromised
Solution Approach 1:
An intermediate portion is introduced between the light reflecting portion and the light absorbing portion. This intermediate layer acts as a transition zone with intermediate reflectivity, smoothly transitioning between the high reflectivity of the reflecting portion and the high absorptivity of the absorbing portion, thereby improving optical performance and contrast without significantly increasing structural complexity
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 device enhances light use efficiency by reflecting non-transmitted polarized light back to the backlight unit and absorbing unnecessary light, improving contrast and manufacturing efficiency while maintaining structural integrity.
Implementation Method 1
a wire grid type polarized-light splitting device has been proposed, which may include a 'wire grid,' e.g., a pattern of substantially parallel ridges having a conductive material thereon, having a pitch smaller than a wavelength of incident light so as to transmit light polarized perpendicular to the grid and reflect light polarized parallel to the grid
Implementation Method 2
the dichroic polarizing film absorbs light polarized perpendicular to a transmission axis
Implementation Method 3
Forming the non-transmissive layer may include depositing the non-transmissive layer by varying a deposition angle according to a height of the non-transmissive layer
Data Source
AI summary
A polarized-light splitting device includes a transmissive base member having a base portion and pattern of ridges on the base portion, and a non-transmissive layer on the ridges, wherein the non-transmissive layer includes a light reflecting portion, and a light absorbing portion.