Liquid Crystal Panel Deterioration Detection via Wavelength Filtering
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Solution Overview
Problem
Existing projection-type display devices face challenges in accurately monitoring the deterioration of liquid crystal panels due to high-intensity light exposure, as current techniques cannot distinguish between deterioration caused by the liquid crystal panel or the light source unit.
Innovation Solution
Incorporating an optical sensor device that detects radiated light with a wavelength range longer than the incident light, specifically using a filter to limit the wavelength to 600 nm to 650 nm, to monitor photoluminescence changes in the liquid crystal panel, allowing for the detection of deterioration and determination of the liquid crystal panel's service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an optical sensor detects chromaticity or illuminance of modulated light, then cooling fan control is enabled, but deterioration source identification fails
Solution Approach 1:
The patent introduces a wavelength selection filter as an intermediary component between the light source and optical sensor. This filter transmits only specific wavelength ranges (e.g., blue light at 450-480nm) while blocking other wavelengths, enabling the sensor to detect photoluminescence from the liquid crystal panel without interference from the light source or other optical components. This resolves the contradiction by providing precise deterioration detection capability while maintaining the cooling control function.
Solution Approach 2:
The patent applies local quality by using wavelength-specific detection for different measurement purposes. The optical sensor system is configured to detect specific wavelength ranges that correspond to photoluminescence from the liquid crystal panel, distinct from the broader spectrum used for general illuminance measurement. This enables simultaneous cooling control and precise deterioration detection through differentiated wavelength analysis.
2Device complexity
If general optical detection is used for cooling control, then operational simplicity is maintained, but liquid crystal panel deterioration monitoring fails
Solution Approach 1:
The patent segments the optical detection function into multiple wavelength-specific detection channels. By using a wavelength selection filter that transmits only specific wavelength ranges, the system can separately detect photoluminescence from the liquid crystal panel (indicating deterioration) while maintaining the broader cooling control function. This segmentation enables reliable deterioration monitoring without requiring a completely separate detection system.
Solution Approach 2:
The patent changes the detection parameter from general illuminance/chromaticity to wavelength-specific photoluminescence intensity. By monitoring the intensity of light at specific wavelengths (e.g., 600-650nm for red photoluminescence from blue light excitation), the system can reliably detect liquid crystal panel deterioration. The wavelength selection filter enables this parameter change while keeping the overall device complexity manageable.
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
Effectively monitors the deterioration of liquid crystal panels by detecting photoluminescence changes, enabling timely notification and potential correction of the display quality, thereby extending the service life and maintaining image quality.
Implementation Method 1
an optical sensor device configured to detect radiated light that is radiated from the first liquid crystal panel when light having a first wavelength range enters the first liquid crystal panel, the radiated light having a wavelength range that is longer than the first wavelength range
Data Source
AI summary
In a display device, when blue (B) light enters a first liquid crystal panel, radiated light radiated from the first liquid crystal panel contains red (R) phosphorescence having a wavelength range longer than blue (B) light due to a deterioration of a liquid crystal material. Thus, in the display device, an optical sensor device is provided behind a mirror comprised of a dichroic mirror to monitor or the like the service life of the first liquid crystal panel on the basis of a result of reception, at the optical sensor device, of light having a frequency band ranging from 600 nm to 650 nm, and makes notification of the result. Furthermore, on the basis of a result from the optical sensor device, an electrode used to suck impurities provided at the first liquid crystal panel is driven to sweep ionic impurities from a display region.