Liquid Crystal Display Light Recycling via Reflective Layers
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Solution Overview
Problem
Conventional liquid crystal display devices suffer from low light utilization efficiency due to absorption of backlight light by gate lines and source lines on the TFT substrate, leading to decreased luminance and increased power consumption, with existing solutions not adequately addressing the absorption of recycled light by polarizing plates.
Innovation Solution
The implementation of a liquid crystal display device configuration where the transmittance of the back side polarizing plate is set higher than the front side polarizing plate, suppressing absorption of recycled light and maximizing recycling efficiency by using a first absorptive polarizing plate and a second polarizing plate with higher transmittance, and optionally incorporating a reflective polarizing plate between the second absorptive polarizing plate and the backlight unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the aperture ratio of pixel is increased to improve luminance, then the luminance increases, but the gate line and source line occupancy area increases causing manufacturing complexity
Solution Approach 1:
The patent converts the harmful absorption of backlight light by gate lines and source lines into a beneficial recycling process. By providing reflective films on both the TFT substrate and backlight unit, the light that would be wasted is reflected back through the liquid crystal layer, transforming the harmful absorption into useful multiple-pass light utilization that improves luminance without increasing aperture ratio.
Solution Approach 2:
The patent enables continuous utilization of backlight light by creating a recycling loop. The reflective film on the TFT substrate reflects light back to the backlight unit, which then re-emits it toward the liquid crystal panel. This continuous circulation of light maximizes the useful action of each photon, improving luminance efficiency without requiring higher aperture ratios.
2Illumination intensity
If the luminance of backlight light is increased to compensate for decreased aperture ratio, then the luminance is maintained, but the power consumption increases
Solution Approach 1:
The patent changes the optical parameters of the system by introducing reflective films with specific reflectance characteristics. Instead of increasing backlight luminance directly, the system modifies the light path parameters to enable multiple passes through the liquid crystal layer, achieving the same luminance output with lower power consumption by improving light utilization efficiency.
Solution Approach 2:
The reflective films enable continuous recycling of backlight light, allowing each photon to contribute multiple times to the display luminance. This continuous useful action reduces the total energy required from the backlight unit to achieve the desired display brightness, thereby lowering power consumption while maintaining luminance.
3Loss of energy
If a reflective film is provided on the TFT substrate to recycle backlight light, then the light utilization efficiency is improved, but the absorbed light is lost into the polarizing plate
Solution Approach 1:
The patent adds another dimension to the light recycling system by providing reflective films on both the TFT substrate and the backlight unit, creating a double-reflection pathway. This dimensional expansion of the recycling loop allows light to be reflected back and forth multiple times, increasing the probability that light will pass through the liquid crystal layer productively rather than being absorbed by the polarizing plate.
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 enhances light utilization efficiency, resulting in higher luminance and reduced power consumption while improving the contrast ratio and outdoor visibility of the liquid crystal display device.
Implementation Method 1
backlight light is recycled by providing a reflective layer in the liquid crystal panel... the incident light which has entered the liquid crystal display device from the light source but has not entered the transmission region, in which the pixel electrode is present, in the liquid crystal display device is reflected by the reflective film to return to the light source side
Implementation Method 2
a transmittance of polarized light vibrating in a direction parallel to a transmission axis of the second polarizing plate being greater than a transmittance of polarized light vibrating in a direction parallel to a transmission axis of the first absorptive polarizing plate... suppressing absorption of recycled light
Data Source
AI summary
The present invention provides a liquid crystal display device which has a high luminance and consumes less power by increasing the utilization efficiency of light. The liquid crystal display device includes: a first absorptive polarizing plate; a liquid crystal panel including a first substrate, a liquid crystal layer, and a second substrate in order from the first absorptive polarizing plate side; a second polarizing plate; and a backlight unit including a reflector in the stated order. The second substrate includes a reflective layer facing the second polarizing plate. A transmittance of polarized light vibrating in a direction parallel to a transmission axis of the second polarizing plate is greater than a transmittance of polarized light vibrating in a direction parallel to a transmission axis of the first absorptive polarizing plate.