Liquid Crystal X-Ray Detector Transmittance Correction
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Solution Overview
Problem
X-ray detectors using liquid crystals face inaccuracies in image diagnosis due to variations in read beam transmittance depending on the field of view, leading to errors in pixel intensity and image distortion, and existing solutions like multi-shooting techniques increase costs and risk current leakage.
Innovation Solution
A method involving measuring reference transmittance of pixels by varying bias voltage, separating electrons and holes, and deriving correction voltages to correct read beam transmittance variations, allowing for accurate X-ray image determination without additional moving mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple X-ray images are captured while moving the optical system, then read beam transmittance accuracy is improved, but device complexity and cost increase due to additional axial movement mechanism
Solution Approach 1:
The patent replaces the mechanical axial movement mechanism with an electrical field-based solution. By applying different voltages to the liquid crystal layer, the refractive index is modulated to correct read beam transmittance variations, eliminating the need for physical movement of the optical system while achieving the same correction effect
Solution Approach 2:
The patent changes the electrical parameter (voltage applied to liquid crystal layer) to control the refractive index and correct transmittance variations. By adjusting the voltage, the optical path difference is compensated without mechanical movement, thereby improving measurement precision while reducing device complexity
2Measurement precision
If multiple X-ray images are captured while moving the optical system, then read beam transmittance accuracy is improved, but loss of time occurs due to multiple captures and movement
Solution Approach 1:
The patent replaces time-consuming mechanical movement with instantaneous electrical field adjustment. The voltage applied to the liquid crystal layer can be changed rapidly without physical displacement, significantly reducing the time required to correct transmittance variations and acquire accurate images
Solution Approach 2:
The patent performs preliminary calibration to establish the relationship between voltage and transmittance correction. This pre-established mapping allows for rapid real-time correction during image acquisition without requiring multiple captures or mechanical adjustments, thereby reducing time loss
3Measurement precision
If multiple X-ray images are captured, then read beam transmittance accuracy is improved, but reliability decreases due to current leakage from liquid crystal layer
Solution Approach 1:
The patent eliminates the need for multiple image captures by using electrical field-based correction, thereby avoiding repeated X-ray exposure and reducing cumulative current leakage in the liquid crystal layer. This maintains image quality stability while achieving the required transmittance accuracy
Solution Approach 2:
The patent performs preliminary voltage adjustment to optimize the liquid crystal layer state before image capture. This preliminary action minimizes current leakage during the imaging process and ensures stable image quality without requiring multiple captures
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 method corrects read beam transmittance errors, ensuring accurate and linear X-ray images, reducing costs and time, and preventing image distortion, while eliminating the need for costly axial movement mechanisms.
Implementation Method 1
liquid crystals that change in polarization transmission characteristics with respect to a read beam when the liquid crystals are irradiated with X-rays
Implementation Method 2
a photoconductive layer of the photoconductive element is irradiated with X-rays and a voltage is applied across two electrodes of the liquid crystal element, the X-rays transmitted through a subject cause polarization in the photoconductive layer
Data Source
AI summary
Disclosed is a method of determining an X-ray image for a liquid crystal X-ray detector. The method includes a first step of measuring a reference transmittance of a pixel while varying a bias voltage in a state in which an X-ray sensing liquid crystal panel is not irradiated with an X-ray, a second step of separating electrons and holes in the X-ray sensing liquid crystal panel by applying a separation voltage and irradiating the X-ray sensing liquid crystal panel with an X-ray, a third step of measuring a detection transmittance of a pixel by applying a measurement voltage to the X-ray sensing liquid crystal panel, a fourth step of deriving a bias voltage of a reference transmittance of the pixel corresponding to the detection transmittance, and a fifth step of determining an X-ray image of the pixel by subtracting the measurement voltage from the bias voltage derived in the fourth step.