THORLABS QS15 Series User manual

QS15 & QS20 Series
1- & 2-Axis Galvo
Scanners
User Guide

QS15 & QS20 Series Galvo Scanners
Table of Contents
Chapter 1 Warning Symbol Definitions.............................................................................................. 1
Chapter 2 Safety .................................................................................................................................... 2
2.1. Safety Information...........................................................................................................2
2.2. General Warnings............................................................................................................2
Chapter 3 Introduction.......................................................................................................................... 4
Chapter 4 Quick Connect Guide.......................................................................................................... 5
Chapter 5 Specifications ...................................................................................................................... 6
5.1. Galvo Scanner Specs......................................................................................................6
5.2. Mirror Coating Specs......................................................................................................6
Chapter 6 Connectors........................................................................................................................... 7
Chapter 7 Heat Sink Requirements..................................................................................................... 8
Chapter 8 Mounting Requirements..................................................................................................... 9
Chapter 9 Limited Warranty................................................................................................................10
Chapter 10 Regulatory...........................................................................................................................11
Chapter 11 Thorlabs Worldwide Contacts..........................................................................................12

QS15 & QS20 Series Galvo Scanners Chapter 1: Warning Symbol Definitions
Rev A, June 20, 2022 Page 1
Chapter 1 Warning Symbol Definitions
Below is a list of warning symbols you may encounter in this manual or on your device.
Symbol
Description
Direct Current
Alternating Current
Both Direct and Alternating Current
Earth Ground Terminal
Protective Conductor Terminal
Frame or Chassis Terminal
Equipotentiality
On (Supply)
Off (Supply)
In Position of a Bi-Stable Push Control
Out Position of a Bi-Stable Push Control
Caution: Risk of Electric Shock
Caution: Hot Surface
Caution: Risk of Danger
Warning: Laser Radiation
Caution: Spinning Blades May Cause Harm

QS15 & QS20 Series Galvo Scanners Chapter 2: Safety
Page 2 MSTN000968-D02
Chapter 2 Safety
2.1. Safety Information
The following safety symbols may be used throughout the handbook and on the equipment itself.
CAUTION
Caution is given when there is a possibility of damage to the product.
WARNING
Given when there is danger of injury to users.
2.2. General Warnings
CAUTION
Excessive moisture may impair operation. Spillage of fluid, such as sample solutions, should be
avoided. If spillage does occur, clean up immediately using absorbant tissue. Do not allow spilled
fluid to enter the internal mechanism.
WARNING
Although the unit does not emit radiation, it does redirect laser radiation emitted from other devices.
Operators must follow all safety precautions provided by the manufacturer of any associated laser
devices.
WARNING
Safety precautions should be taken to avoid exposure to laser radiation. During system shutdown or
malfunction, the scanner can point the beam anywhere within its range of rotation. It is up to the user
of these scanners to limit the exit aperture of the laser beam in order to provide laser safety.
•When unpacking the galvanometer, care should be taken not to damage the rotor. The rotor and bearing
assemblies can be easily damaged if impacted or loaded with excessive forces. Furthermore, the
galvanometer should be kept free of dirt, dust, oil, and other contaminants.
•Do not make physical contact with the galvo mirrors. If absolutely necessary, handle the mirrors with
extreme care. Use finger cots or gloves before touching any mirrors or optical elements. Finger oils will
damage the reflective coatings on the mirrors.
•Do not remove or adjust the mirror. Any changes to this mounting can affect the resonance and cause the
system to go unstable during operation.

QS15 & QS20 Series Galvo Scanners Chapter 2: Safety
Rev A, June 20, 2022 Page 3
•When unpacking the servo drive electronics, caution should be used to protect against static electricity
damage. Failure to use proper static protection may cause damage to the servo driver boards and void the
manufacturer’s warranty.
•Galvanometers packaged with servo drivers (and mirrors) are factory tuned as a set. Each galvanometer
is tuned to a specific a servo driver and MUST stay together as a set. For systems using more than one
galvanometer and servo amplifier, the units are not interchangeable. Servo driver boards have a copy of
their mating scanner serial number on the bottom.
•Servo drivers must be properly attached to a heat sink. Refer to Chapter 7: Heat Sink Requirements for
proper heat sinking instructions. Failure to heat sink the servo driver could result in overheating of
components, which could damage the driver and void the manufacturer’s warranty.
•Every servo driver is tuned to accept a specific input voltage range. Using input command voltages outside
of this range may cause hardware damage. Thorlabs will not be responsible for damage as a result of
command input voltages that exceed the specified voltage range.
•Proper voltage and ground need to be supplied prior to operation. The power supply should have sufficient
voltage and current for the application. Noisy power supplies can result in poor scanner performance.
Switching power supplies can often introduce unwanted noise.
•Be sure that the mirror does not collide with any other mirrors or objects.
•Your optical scanners were carefully tested and inspected before packaging. Please report any damage to
your shipping company immediately.

QS15 & QS20 Series Galvo Scanners Chapter 3: Introduction
Page 4 MSTN000968-D02
Chapter 3 Introduction
This manual covers the installation and use of Thorlabs’ QS15 & QS20 Series 1- & 2-Axis Galvanometer Scanners.
These galvo scanners are specifically designed to rotate optical scanning mirrors at a high bandwidth and then
settle to a high degree of accuracy and repeatability. They are designed to carry a balanced inertial load, matched
to the size of the stator and rotor combination. The exact inertia that can be driven depends on the application,
which in turn specifies a speed and settling accuracy requirement.
WARNING
Safety precautions should be taken to avoid exposure to laser radiation. During system shutdown or
malfunction, the scanner can point the beam anywhere within its range of rotation. It is up to the user
of these scanners to limit the exit aperture of the laser beam in order to provide laser safety.
CAUTION
This manual contains all the information necessary to install and operate the the galvo scanner. Servo
drivers are factory tuned with a matched galvanometer and mirror. Do not adjust the servo driver in
the field. Only factory trained service technicians should adjust any of the potentiometers on the
board. If it becomes necessary to return a servo driver board to the factory, the matching
galvanometer and mirror should be returned along with it. Any unauthorized attempt to adjust the
servo by an untrained individual could result in serious damage to the scanner, mirror, and
electronics.
CAUTION
Galvanometer bearings are delicate and prone to damage if not handled with care. Never apply
excessive axial or radial force to the galvanometer rotor. Dropping the galvanometer could damage
the mirror, rotor, bearings, or position detector.

QS15 & QS20 Series Galvo Scanners Chapter 4: Quick Connect Guide
Rev A, June 20, 2022 Page 5
Chapter 4 Quick Connect Guide
The instructions below serve as a quick guide. Before connecting the servo drives, please read Chapter 2 for safety
precautions and refer to the servo driver manual for additional information and instructions.
•Set your dual voltage supply to the necessary output voltage range (per the driver manual) before
connecting the galvanometer power cables.
•The servo drive accepts command inputs within the range of ±5 V. Inputs outside of this voltage range may
damage hardware.
•After adjusting the power supplies, turn them off before making any connections to the servo drive(s).
•The servo drive(s) should be properly mounted to a sufficient heat sink.
•Galvanometers should be mounted properly to avoid mirror collisions.
•Connect the Galvanometer Position Detector & Drive (9 Pin) to the Servo Driver Board (J1). Repeat if there
is more than one Galvanometer.
•Connect the Scanner Drive (black, 3 Pin) to the Servo Driver Board (J6). Repeat if there is more than one
Galvanometer.
•Connect the Power Cable(s) from the Power Supply to the Servo Driver Board(s) (J7).
•Connect the Command Input Cable(s) from the function generator or host system to the servo drive board(s)
(J3).
Note: Do not, under any circumstances, remove the mirror from the galvanometer. Removing and re-
mounting the mirror changes the resonant frequency of the unit and requires re-tuning before operation.
Failure to re-tune units after mirror changes can result in hardware damage. If you need to remove the
mirror in order to mount your galvanometer, please contact Thorlabs Tech Support for guidance.
Note: For systems using more than one galvanometer and servo amplifier, the galvanometer is match-tuned
to a specific servo amplifier. The units are not interchangeable.

QS15 & QS20 Series Galvo Scanners Chapter 5: Specifications
Page 6 MSTN000968-D02
Chapter 5 Specifications
5.1. Galvo Scanner Specs
Item # Prefix
QS15
QS20
Max Beam Diameter
15 mm
20 mm
Mirror Substrate
Fused Silica
Step Response Time (0.4° Optical)
600 µs
650 µs
Mechanical & Electrical Specifications
Rated Excursion
±22.5° Opticala
Rotor Inertial Load
Recommended
1.8 g·cm2
Max
9 g·cm2
Torque Constant
180 000 dyne·cm/A
Coil Resistance
3.0 Ω
Coil Inductance
530 µH @ 1 kHz
Position Detector
Type
Optical
Linearity
99.8% @ ±20°
Gain Drift
50 ppm/°C
Offset Drift
30 µrad/°C
Repeatability
10 µrad
Output Signal (Typ.)
Differential Mode
7.1 µA/° Optical
Common Mode
385 µA
Supply Current
30 - 40 mA
General Specifications
Operating Temperature
0 to 40 °C (Non-Condensing)
Storage Temperature
-10 to 50 °C
Servo Shaft Size
Ø22 mm x 50 mm
a. The optical angle is 2x the mechanical angle.
5.2. Mirror Coating Specs
Item # Suffix
-AG
-Y3
-Y1
-CD
Coating Type
Protected Silver
Hard Dielectric for
Nd:YAG Laser
3rd Harmonic
Hard Dielectric for
Nd:YAG Laser
Fundamental
Dielectric on Metal
for CO2Laser
Absolute
Reflectance
≥92% (450 - 500 nm)
≥94.5% (500 - 2000
nm)
≥98% (2 - 10.6 µm)
≥99% (355 nm)
≥80% (633 nm)
≥98% (1064 nm)
≥80% (633 nm)
≥99.5% (10.64 µm)
≥80% (633 nm)
Surface Quality
(Scratch-Dig)
40-20
20-10
40-20
40-20

QS15 & QS20 Series Galvo Scanners Chapter 6: Connectors
Rev A, June 20, 2022 Page 7
Chapter 6 Connectors
The 9-pin connector carries the two differential position detector signals (ib and ia), the AGC voltage (Oscillator
Power), the two motor drive signals, and ground. These signals connect to the galvanometer connector on the servo
drive board (see servo drive manual for more details).

QS15 & QS20 Series Galvo Scanners Chapter 7: Heat Sink Requirements
Page 8 MSTN000968-D02
Chapter 7 Heat Sink Requirements
CAUTION
The servo driver board MUST be attached to an additional heat sink before applying power. Failure to
provide proper heat sinking could result in damaged components and void the manufacturer’s
warranty.
These galvanometers typically do not require special heat sinking. Under most operating conditions, the
galvanometer’s motor will radially transfer its heat from the motor to the surrounding air. The galvanometers are
mounted by clamping in the motor section such that heat generated by the galvanometer motor does not cause
thermal drift in the position detector.
Temperature changes in the galvanometer environment can cause small amounts of drift in the galvanometer’s
position (see specifications). It is recommended that the galvanometer(s) be operated at the most rigorous level
required during the user’s application, rather than alternating between rigorous and light operation. This will ensure
that the drift remains a constant offset over the course of operation.
Monitor the temperature of the galvanometer on the mid section of the galvanometer stator. The stator chassis
temperature should not exceed 45 °C. If the operating temperature of the galvanometer exceeds this temperature,
additional heat sink capacity will be required. This can be accomplished by blowing cool air across the motor or by
clamping additional heat sinking material to the motor chassis.