Browsing by Author "Hortschitz, Wilfried"

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High-resolution proximity sensor using flexible semi-transparent organic photo detector
(2017-10-01)
Chen, Chao-Hsuan
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Lin, Ching-Fu
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Wang, Kuan-Hsun
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Liu, Hung-Chuan
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Zan, Hsiao-Wen
We propose a flexible proximity sensor to detect sub-centimeter distance with an ultra-high displacement resolution. The proximity sensor is realized by integrating a semi-transparent organic photo detector with a transparent top electrode and a finger-type bottom electrode. By placing the semitransparent finger-type photodetector on a light source, such as a light-emitting diode (LED), the photodetector can detect the light reflected from an object on top of the sensor. With the highly compact structure, the detecting range is from 1 mm to 30 mm. From 1 mm to 10 mm, the sensor is particularly sensitive and delivers a resolution of 1 mm. The air-stable photodetector can also be fabricated on a flexible substrate without encapsulation, enabling the integration with arbitrary light sources. After 1000 times bending, the flexible photodetector shows no obvious degradation. (C) 2017 Elsevier B.V. All rights reserved.
Making Optical MEMS Sensors more compact using Organic Light Sources and Detectors
(2014-01-01)
Sauter, Thilo
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Hortschitz, Wilfried
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Steiner, Harald
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Stifter, Michael
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Chiao, Hsin
Vibration and displacement sensors need to be compact for many applications in automation or consumer electronics, and microelectromechanical structures are a convenient way to implement such sensors. For these MEMS devices, optical readout methods have proven to be superior to capacitive or piezoresistive strategies in terms of sensitivity as well as noise and interference immunity, however the integration of light sources and detectors is not easily possible. This paper presents an approach to use organic optoelectronic devices for the readout. OLED and OPD (organic photo detector) are structured on the glass substrate and cover encapsulating the MEMS devices, allowing for a tightly integrated sensor based on vertical light flux modulation by a horizontally moving proof mass. The paper describes the principle sensor structure as well as the fabrication of suitable organic devices. First test results show that the approach is feasible.
Solution-processed finger-type organic proximity sensor with high displacement resolution
(2016)
Liao, Jung-Sung
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Wang, Kuan-Hsun
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Zan, Hsiao-Wen
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Meng, Hsin-Fei
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Yeh, Ping-Hung
Proximity sensors are interesting devices for applications like smart homes or human-machine interfaces. This work investigates a cheap and compact short-range proximity sensor based on an organic photo detector combined with a commercial LED. Low-cost solution-processed organic materials are used, and low process temperatures at 140 degrees C also facilitate future integration on, e.g., plastic substrates. In particular, to avoid damage of the organic layer during the patterning process, a new organic photo detector with a semi-transparent organic active layer and a transparent silver nanowire top electrode was designed. The proposed sensor can be realized by using only one shadow mask to pattern the opaque bottom electrode layer. The opaque finger-type bottom electrode not only partly shields the light emitted from below the device, but also defines the active regions with vertical electric field to generate and collect photo current. In the experiments conducted in this paper, the maximum detection distance was found to be 2 cm, whereas the lower end of the measurement range was 0.2 cm.