High-speed chemical imaging system based on front-side-illuminated LAPS

Akinori Itabashi, Naoki Kosaka, Ko Ichiro Miyamoto, Torsten Wagner, Michael J. Schöning, Tatsuo Yoshinobu

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


The chemical imaging sensor is a semiconductor-based chemical sensor that can visualize the spatial distribution of specific ions on the sensing surface. The conventional chemical imaging system based on the light-addressable potentiometric sensor (LAPS), however, required a long time to obtain a chemical image, due to the slow mechanical scan of a single light beam. For high-speed imaging, a plurality of light beams modulated at different frequencies can be employed to measure the ion concentrations simultaneously at different locations on the sensor plate by frequency division multiplex (FDM). However, the conventional measurement geometry of back-side illumination limited the bandwidth of the modulation frequency required for FDM measurement, because of the low-pass filtering characteristics of carrier diffusion in the Si substrate. In this study, a high-speed chemical imaging system based on front-side-illuminated LAPS was developed, which achieved high-speed spatiotemporal recording of pH change at a rate of 70 frames per second.

Original languageEnglish
Pages (from-to)315-321
Number of pages7
JournalSensors and Actuators B: Chemical
Publication statusPublished - 2013


  • Chemical imaging sensor
  • Front-side illumination
  • LAPS pH distribution
  • Light-addressable potentiometric sensor


Dive into the research topics of 'High-speed chemical imaging system based on front-side-illuminated LAPS'. Together they form a unique fingerprint.

Cite this