The PZ-2000 has been specifically designed to provide a high resolution, and highly repeatable, means of controlling the X, Y, and Z position of an inverted microscope's stage. The XY axes derive their precise control through the use of closed-loop DC servomotors employing high-resolution rotary encoders for positioning feedback. Optional linear encoders improve repeatability to less than 300 nm (typical) compared to the standard rotary encoder's 800 nm (typical) repeatability rating.
By using closed-loop control for the stage position, there is no chance that the stage will become lost, as can occur with open-loop micro-stepped stages after a number of moves and direction changes. The XY stage utilizes crossed-roller slides, high-precision lead screws, and zero-backlash miniature geared DC servomotors for smooth and accurate motion. The top plate of the stage accepts standard K-size slide inserts that are available for any sample, i.e., slides, petrie dishes, multi-well plates, etc. The slide insert is moved in the Z-axis via a piezo element with a range of 100 µm with nanometer accuracy. By moving the sample in the Z-plane, any objective can be used, eliminating twisting wires or needed spacers as required when a piezo element is put onto a single objective. The microprocessor-controlled MS-2000 control unit provides for RS-232 and USB communication with a host computer for control of the XYZ axis.
The new PZ-2200 model now incorporates new 200 micron piezo elements in the Z plate for twice the vertical Z-axis travel as a regular PZ-2000. All other specifications and dimensions remain the same.
For information on piezo-Z stages for upright microscopes, click here.
Features
- Closed-loop control of the X, Y, and Z-axes for precise positioning and highly repeatable focusing
- Wide dynamic speed range with adjustable trapezoidal move profiles
- Smooth adjustable dual-range joystick control
- Backlit LCD display shows X, Y, and Z coordinates
- "Zero" and "Home" button for simple stand-alone operations
- Compact ergonomic tabletop control unit size is 6"D x 9"W x 3"H (9 x 23 x 16½ cm)
- Proven operation with many popular software packages
Advantages of the PZ-2000
Previously, available standard piezo elements had to be mounted to a single microscope objective to obtain nanometer-scale movement in the Z-plane. In contrast, the PZ-2000 moves the entire specimen in the Z-plane. This offers several important advantages:
- By moving the entire sample in the Z-plane, any objective can be used instead of only the single objective with mounted piezo.
- The PZ-2000 eliminates the twisting of wires that create failures within objective-mounted piezo systems.
- No spacers are required on any objectives with the PZ-2000. Spacers are required with objective-mounted piezo systems, however, this added distance interferes with proper DIC operation. The PZ-2000 allows unhindered DIC operation on all supported microscopes.
- The PZ-2000's 100 micron (and the PZ-2200's 200 micron) limited travel range of the piezo element can be compensated by adding ASI's focus controller to the fine focus shaft of the microscope. This precision closed-loop DC servo motor drive can position the sample anywhere within the microscope's range of focus. From there the piezo element of the PZ-2000 can be used for ultra-fast nanometer positioning.
- The PZ-2000 offers all of the advantages of a piezo focusing system with none of the drawbacks.
Specifications for Standard Configuration
| XY axis range of travel |
110 mm x 90* mm |
| XY axis resolution (encoder step) |
0.088 µm |
| XY axis lead screw accuracy |
0.25 µ/mm |
| XY axis RMS repeatability |
< 0.8 µm (typ) |
| XY axis maximum velocity |
7 mm/sec |
| Z axis range of travel (± 5%) |
100 µm = PZ-2000 |
| 200 µm = PZ-2200 |
| Z axis resolution |
1.5 nm |
| Z axis repeatability |
± 1 nm |
| Z axis maximum velocity with settling time |
5 mm/sec |
| Z axis resonant frequency (unloaded) |
> 1 KHz |
| Z axis top plate maximum load |
500 grams |
| Z axis top plate stiffness (± 20%) |
3 N/µm |
| Z axis top plate in-plane tilt (typical) |
10 µrad |
(with 6.35 mm pitch lead screws on XY stage)
( * Y-range is 60 mm on IX-71,81 and DMI-series microscopes)
NANO-DRIVETM Piezo Controller Specifications
| Analog interface (front panel BNC) |
0.0 to 10.0 Vdc |
| RS-232 interface (via ASI's MS-2000 controller) |
16-bit D/A converter |
| Stage interface |
1.5 m cable with DB9 connector |
| Front panel adjustment |
Sensor Offset |
| Output voltage range |
-5 to +150 V |
| Output current |
150 mA |
| Power requirement |
120 VAC |
PZ-2000 Options
- XY axes Linear Encoders for high-accuracy positioning. Linear encoder resolution is 20 nm, with a scale accuracy of 0.5 µm per 10mm and 1.5 µm per 100mm. Positioning resolution at sample is about 50 nm. Linear encoders improve repeatability to less than 300 nm (typical).
- The CRIFF Continuous Reflective-Interface Feedback Focus System provides a very high level of focus stability, substantially eliminating focus drift caused by temperature variations as well as mechanical drifts of the microscope mechanisms.

- Auto Focus Option (requires an NTSC or PAL composite video signal).
- ASI's proven line of Z-axis drives can also be added to the fine focus shaft of the microscope to provide Z-axis positioning with a resolution of 50 nm throughout the range of the microscope's travel. The piezo unit can then be used for fast and accurate Z-axis positioning to any point within the range of travel.
- Other lead screw pitches are available for faster XY translation, or for more precise positioning when using standard rotary encoders.
PZM-2000 Piezo Z-axis Control for Manual Inverted Stages
If you do not require automated XY movement, but do require automated Z-axis positioning for acquiring precise Z-axis stacks, then the PZM-2000 is the solution. On select models of microscopes, ASI can modify or exchange your existing OEM stage with a PZM-2000 unit. Contact ASI with information about your current setup and see if we can provide you with nanometer-scale Z-axis positioning.