# On the Feasibility of an LCD-Based Real-Time Converter for Ionizing Radiation Imaging

## TL;DR

This paper introduces a new LCD-based device that converts ionizing radiation into visible images in real time using a simple structure and materials.

## Contribution

The novel cascade converter uses LCD technology and functional layers to enable real-time ionizing radiation imaging with a simple design.

## Key findings

- The cascade converter successfully converts X-ray radiation into visible images through a three-stage process involving light emission and voltage generation.
- The device uses a twisted nematic liquid crystal structure driven by an effective electric field for real-time imaging.
- The converter has a simple structure and manufacturing process, making it suitable for portable radiation detection and dosimetry.

## Abstract

Here we present the cascade converter (CC), which provides real-time imaging of ionizing radiation (IoR) distribution. It was designed and manufactured with the simplest architecture, utilizing liquid crystal display (LCD) technology. Based on two merged substrates with transparent electrodes, armed with functional layers, with the cell filled with nematic liquid crystal, a display-like, IoR-stimulated CC was achieved. The CC comprises low-absorbing polymer substrates (made of polyethylene terephthalate—PET) armed with a transparent ITO electrode covered with a thin semipermeable membrane of polymer (biphenylperfluorocyclobutyl: BP-PFCB) doped with functional nanoparticles (NPs) of Lu2O3:Eu. This stack was covered with a photoconductive layer of α-Se and finally with a thin polyimide (PI) layer for liquid crystal alignment. The opposite substrate was made of LCD-type glass with ITO and polyimide aligning layers. Both substrates form a cell with a twisted structure of nematic liquid crystal (TN) driven with an effective electric field Eeff. An effective electric field driving TN structure is generated with a sum of (1) a bias voltage VBIAS applied to ITO transparent electrodes and (2) the photogenerated additional voltage VXray induced between ITO and α-Se layers with a NPs-doped BP-PFCB polymer layer in-between. The IoR (here, X-ray) conversion into real imaging of the IoR distribution was achieved in the following stages: (1) conversion of IoR distribution into non-ionizing red light emitted with functional NPs, (2) transformation of red light into an electric charge distributed in a layer of the photoconductive α-Se, which is what results in the generation of distributed voltage VXray, and (3) a voltage-mediated, distributed switching of the TN structure observed with the naked eye. The presented imaging device is characterized by a simple structure and a simple manufacturing process, with the potential for use as a portable element of IoR detection and as a dosimeter.