D-015
D-050
D-100 | Sub-Nanometer-Resolution CapacitivePosition Sensors |
| The product You were Looking for was moved Click Here for new Address - Measuring Range to 1000 µm
- Resolution < 0.01 nm
- Linearity to 0.003%
- Bandwidth to 10 kHz
- Integrated Linearization System (ILS)
- Custom Designs
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Measurement Method
Capacitive position sensors are analog non-contact devices. A two-electrode capacitive position sensor consists of two RF-driven plates that are part of a capacitive bridge. One plate (probe) is fixed, the other plate (target) is connected to the object to be positioned. Since the plate size and the dielectric medium (air) remains unchanged, capacitance is directly related to the distance between the plates. Ultra-precise electronics convert the capacitance information into a signal proportional to distance.
Resolution
Resolution on the order of picometers is achievable with short-range, two-electrode capacitive position sensors (single-electrode capacitive position sensors provide significantly less resolution, linearity and accuracy than two-electrode sensors).
Theoretical measurement resolution is limited only by quantum noise. In practical applications, stray radiation, electronics-induced noise and geometric effects are the limiting factors. For example, with the 100 µm range, a D-100.00 sensor and E-509.C1A electronics, the effective noise factor is 0.02 nm / √ Hz. This translates to 0.2 nm at 100 Hz bandwidth. The maximum standard bandwidth (jumper selectable) is 3 kHz.
Figure 2 shows a D-015, 15 µm capacitive position sensor and an interferometer, both measuring nanometer-range actuator cycles. The graphs clearly show the superior resolution of the capacitive position sensing technique.
Technical Data: Capacitive Sensors
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| | | | Sensor Models | D-015.00 | D-050.00 | D-100.00 | Units |
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| | Material | Aluminum* | Aluminum* | Aluminum* | |
| | Active Surface | 16.6 | 67.7 | 113.1 | mm² |
| | Nominal Measuring Distance | 15 | 50 | 100 | µm |
| | Extended Measuring Distance | 45 | 150 | 300 | µm |
| | Therm. Drift ** | 50 | 50 | 50 | ppm/K |
| | Operating temperature range | -20 to +80 | -20 to +80 | -20 to +80 | °C |
| | * Other materials, measuring ranges and form factes or request.
** Change of the active measuring surface in parts per million as referred to the selected measuring range
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Fig. 1. D-015, D-050, D-100 ultra-high- resolution capacitive position sensors provide up to 10,000 times higher resolution than calipers
Fig. 2. Motion of a high-resolution PI NanoPositioning system as measured with D-015 capacitive position sensor and a laser interferometer (bandwidth set to 3 kHz).
D-015.00 (dimensions in mm)
D-050.00 (dimensions in mm)
D-100.00 (dimensions in mm)
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