Photoresistor Devices (image) Osaka University Share Print E-Mail Caption a: The device structure. b: The on-off ratios (the ratio of conductivity with/without pseudo-sunlight) of the photoresistor devices. The higher the on-off ratio, the better the performance of the photoresistor. Credit Osaka University Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.