Backlight Module Multilayer Polarizer Light Loss Reduction
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Solution Overview
Problem
Conventional backlight modules for liquid crystal displays suffer from high optical absorption and transmission losses due to reflectors, resulting in reduced light availability and degraded performance, especially when attempting to achieve singly polarized light output.
Innovation Solution
A backlight module incorporating an optical cavity with a multilayer polarizer that reflects and depolarizes light, utilizing rod-like supramolecules forming a three-dimensional structure to selectively transmit light of one polarization state while reflecting orthogonal polarization, thereby minimizing losses and enhancing light utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional reflectors are used in the lamp cavity and at the back surface of the light guide, then light reflection is achieved, but optical absorption and transmission losses increase (4-15% of incident light is absorbed or transmitted)
Solution Approach 1:
The patent changes the optical parameters of the reflector surface by applying a reflective retroreflective film with specific geometric structures (prisms, pyramids, or spheres) that create retroreflection. This geometric parameter change enables the reflector to return light to its source direction with minimal absorption and transmission losses, resolving the contradiction between achieving light reflection and minimizing energy loss.
Solution Approach 2:
The patent uses a composite structure combining a reflective retroreflective film with a translucent or transparent sheet material. This composite material integrates the light-reflecting properties of the retroreflective film with the light-transmitting properties of the sheet, enabling simultaneous light reflection and minimal absorption/transmission losses in the backlight module.
2Ease of operation
If a polarizing plate is arranged between the LCD device and the backlight module to obtain singly polarized light beam output, then polarization control is achieved, but light intensity is reduced to less than half of the original light beam
Solution Approach 1:
The patent extracts the polarization function from the traditional polarizing plate and relocates it to the reflector component. The reflective retroreflective film inherently provides polarization control through its geometric structure, eliminating the need for a separate polarizing plate and thereby preventing the 50% intensity loss that would result from using a conventional polarizing plate.
Solution Approach 2:
The reflective retroreflective film performs multiple functions simultaneously: it reflects light back toward the source, provides polarization control, and maintains high light transmission efficiency. This multi-functionality eliminates the need for separate components and avoids the intensity reduction associated with conventional polarization methods.
3Ease of manufacture
If conventional reflectors with high absorption and transmission are used, then light reflection is provided, but light availability to the viewer is reduced
Solution Approach 1:
The patent converts the harmful effects of conventional reflectors (high absorption and transmission losses) into beneficial retroreflection. The geometric structures of the retroreflective film naturally redirect light back toward its source with minimal loss, transforming what would be wasted light into useful light available to the viewer.
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 significantly reduces light absorption and transmission losses, achieving high light transmission efficiency and improving the overall performance of the backlight module by effectively managing light polarization and distribution.
Implementation Method 1
a multilayer polarizer which reflects and depolarizes light that is incident upon a front surface of the optical cavity. The layers are arranged in such a way that light of a polarization substantially parallel to a transmission axis of the multilayer polarizer is substantially transmitted and light of substantially orthogonal polarization is substantially reflected
Implementation Method 2
an optical cavity for reflecting and depolarizing light that is incident upon a front surface of the optical cavity
Implementation Method 3
Light guides are made of optically transparent materials transmitting light along their length by means of total internal reflection
Implementation Method 4
At least one of the layers comprises rod-like supramolecules forming at least partially a three-dimensional structure in the layer
Data Source
AI summary
The present invention relates generally to backlight modules for display devices and liquid crystal displays incorporating the same, and more particularly, to a backlight module for generating light with a single polarization state. The present invention provides a backlight module, comprising an optical cavity for reflecting and depolarizing light that is incident upon a front surface of said optical cavity and a multilayer polarizer comprising a plurality of layers. Said multilayer polarizer faces the front surface of the optical cavity and the layers are arranged in such a way that a light of polarization substantially parallel to the transmission axis of said multilayer polarizer is substantially transmitted and the light of substantially orthogonal polarization is substantially reflected by said multilayer polarizer in at least one predetermined wavelength subrange of the visible wavelength range. At least one of said layers comprises rod-like supramolecules forming at least partially a three-dimensional structure in the layer. The present invention also provides a liquid crystal display, comprising a liquid crystal cell, a front polarizer, and a backlight module according to the first aspect of the present invention. The multilayer polarizer of the backlight module faces the back panel and serves as a back polarizer of the liquid crystal display.