Amplified Piezo Stage for Microscope Slides

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The LPS710E/M stage and LPSA1/M slide holder attached to a MP10/M rigid stand for use with a Cerna^® microscope.

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Once mounted onto the LPS710(/M), secure a microscope slide onto the LPSA1(/M) using the spring-loaded plunger.

Features

• Long Range Z-Axis Motion
  • 1100 µm When in Open Loop
  • 800 µm When in Closed Loop
• Paired, High-Precision Controller and Capacitive Feedback Sensors Provide High-Resolution Positioning
  • 2 nm Resolution in Open Loop
  • 6 nm Resolution in Closed Loop
• Holder Secures Slides Between 2.88" to 3.00" Long, Up to 0.055" (1.4 mm) Thick and 1.00" (25.4 mm) Wide
• Kinesis^® Interface, ThorImage^®LS Integration, and Control via External Voltage

The LPS710E(/M) Amplified Piezo Stage provides long range, fine focus Z-axis travel for a microscope slide while maintaining a compact, low-profile footprint. It features submicron repeatability, nanometer positioning resolution, low angular error, and fast millisecond response and settling times. When used with the LPSA1(/M) microscope slide holder, the stage is ideal for imaging modalities requiring sensitive sample positioning and sectioning, such as confocal laser scanning microscopy. This stage is not compatible with trans-illumination.

The stage is driven by a discrete piezo stack housed within a hardened steel flexure structure that preloads the piezo stack and amplifies its displacement. When controlled in a closed loop, which provides higher precision positioning and reduced hysteresis, this results in a maximum total displacement of 800 µm; when operating in open-loop, the resulting maximum total displacement is 1100 µm. Built-in capacitive feedback sensors along with our high-precision piezo controller provide 6 nm resolution in closed-loop operation, enabling active compensation for short- and long-term drifts. When used in open loop, the controller will provide an accurate readout of the stage position with a resolution of 2 nm. An engraved arrow on the side of the unit indicates the direction of travel. For additional information on piezoelectric device structure and actuation, see the Piezoelectric Tutorial.

The LPSA1(/M) slide holder uses two countersunk cap screws to attach to the 21.0 mm x 21.0 mm mounting surface on the top of the LPS710E(/M). The mounting surface is equipped with four 4-40 (M3) blind mounting holes that are 4.8 mm deep to orient the slide holder in two orthogonal positions on the stage. The slide holder is compatible with microscope slides and test targets, as well as any rectangular optic from 2.88" (73.1 mm) to 3.00" (76.5 mm) long and up to 0.055" (1.4 mm) thick and 1.00" (25.4 mm) wide. Slides are secured using the red, spring-loaded plunger.

In addition to the slide holder, the stage can secure a Ø7 mm optic mount or other 4-40 (M3) equipped component. The base of the stage includes two slots for 1/4"-20 (M6) cap screws and two slots for 4-40 (M3) cap screws that can be used to secure the stage to a stage or breadboard for use with a microscope, such as our Rigid Stands or Translating Platforms, or directly to an optical table. In addition, the stage has two bottom- and side-located 4-40 (M3) mounting holes that can be used to secure the stage using our line of mini-series components.

Each stage is shipped with a piezo controller that has been factory calibrated to the specific stage to achieve maximum accuracy. It is not recommended to operate the piezo stage with a different controller. Piezo control is supported through the included Kinesis GUI, our ThorImage^®LS image acquisition software, or an externally supplied control voltage. See the Software & External Control tab for more details. The controller offers USB and RS-232 interfaces for computer control; a BNC input for sine, sawtooth, and square wave drive signals; and a BNC output that gives either positioning feedback from the scanner's built-in capacitive sensors or a signal proportional to the piezo drive voltage. In addition, a DB15 connector provides signals that can be used for synchronization with external equipment.

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Z Control Panel from ThorImage^®LS Capture Setup Tab


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Fast Z Panel from ThorImageLS Capture Tab

The stage can be driven using the included Kinesis^® GUI, our ThorImage^®LS software for Bergamo^® III and confocal microscopes, or an externally supplied control voltage. In addition, a DB15 connector provides signals that can be used for synchronization with external equipment. Complete details on control are available in the LPS710E Kinesis manual (PDF link).

Open-Loop Operation vs. Closed-Loop Operation
There are two operating modes for positioning the stage: open loop and closed loop. In open-loop operation, which supports a travel range of 1100 µm ± 10%, the user controls the piezo drive voltage (in V). The applied drive voltage corresponds to some amount of stage displacement. For piezoelectric materials, this displacement does not depend linearly on the applied voltage: it exhibits nonlinearity and hysteresis. It is therefore not straightforward to position the stage by choosing the drive voltage. The stage's controller and built-in capacitive feedback sensors measure the stage displacement with
2 nm resolution in open-loop operation.

In closed-loop operation, which supports a travel range of 800 µm, the user directly controls the stage displacement (in µm). The built-in capacitive feedback sensors measure the stage displacement with 6 nm resolution in closed-loop operation.

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Kinesis^® GUI Panel

Kinesis GUI
The Kinesis GUI supports both open- and closed-loop operation. The piezo drive voltage or stage displacement can be directly typed in or incremented or decremented in fixed, user-defined amounts.

In addition, the GUI enables manual PID loop tuning. The default settings are designed to provide stable operation, but manually fine tuning the PID loop and notch filters helps account for the specific objects mass in use in the experiment, reducing positional overshoots and ringing about the commanded objective position.

A screenshot is shown to the left.

ThorImageLS Image Acquisition Software
ThorImageLS supports closed-loop operation. It allows the movement of the stage to be controlled from the same interface as Thorlabs' Bergamo III and confocal microscopes, greatly simplifying experimental integration. For convenience, controls for the stage are found in both the Capture Setup and Capture tabs. Screenshots are shown to the right.

The ThorImageLS software works in conjunction with the Kinesis GUI, so the settings for the IO Control Mode should be set to 'Software + External BNC' before controlling the stage.

Externally Supplied Control Voltage
In this mode, the stage supports both open- and closed-loop operation. The voltage is applied using the external input BNC connector on the controller. The drive voltage or stage displacement that is determined by the input voltage is added to the value that is set in the GUI. If this sum would result in a drive voltage outside the -25 V to +150 V range, those limits will not be exceeded.

The external input BNC connector is typically used with sine, sawtooth, or square drive signals. The maximum frequency of the signal that should be applied depends upon the waveform. For large periodic waveforms (i.e., sine waves that provide >200 µm of total displacement), the recommended drive frequencies are:

• ≤40 Hz for Loads up to 50 g
• ≤30 Hz for Loads from 50 g to 150 g
• ≤20 Hz for Loads from 150 g to 300 g

For staircase waveforms with step sizes up to 50 µm, the minimum time between steps can be as small as the 25 ms typical settling time.

DB15 Connector
For photostimulation, electrophysiology, and optogenetics applications, the DB15 connector on the controller provides several electrical signals that can be used to synchronize the movement of the piezo stage with other equipment, such as multiphoton imaging lasers, patch clamp electrodes, and LED light sources. Details on this connector are available in Appendix A.2 of the Kinesis manual (PDF link).

Piezo Controller Pin Diagrams

Joystick Connector

Female Mini DIN

Pin	Description	Pin	Description
1	RX (Controller Input)	4	+5 V, 100 mA Supply for Joystick
2	Ground	5	TX (Controller Output)
3	Ground	6	Ground

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Items Included with LPS710E(/M) (North American Power Cord Shown)

Item # LPS710E(/M) consists of the following:

• LPS710 or LPS710/M Stage
• PPC001 Piezo Controller
• Power Supply with Region-Specific Power Cord
• USB Cable for Computer Connections
• Storage Case with Slots for Stage and All Optional Accessories

The microscope slide holder and mirror mount are available for purchase separately. The box that houses the LPS710E has an insert for the LPSA1(/M) microscope slide holder and LPSA5(/M) mirror mount.