VariSpec™ LIQUID CRYSTAL TUNABLE FILTERS User’s Manual for VariSpec Seeing life in a new light
Notice The information in this document is subject to change without notice and should not be construed as a commitment by Cambridge Research & Instrumentation, Inc. CRi assumes no responsibility for any errors that may appear in this document. This manual is believed to be complete and accurate at the time of publication. In no event shall CRi be liable for incidental or consequential damages in connection with or arising from the use of this manual.
Contents Chapter 1, Introduction to VariSpec Liquid Crystal Tunable Filters 1 Introduction...........................................................................................................................................................1 Important Features ................................................................................................................................................2 Applications........................................................................................
Programming Examples......................................................................................................................................28 Example 1. Tuning by wavelength...............................................................................................................28 Example 2. Tuning with a palette ................................................................................................................29 Example 3.
Chapter 1 Introduction to VariSpec Liquid Crystal Tunable Filters This chapter provides information about VariSpec liquid crystal tunable filters (LCTFs) that is common to all filter models. Appendices are used to provide additional information, specific to individual models. Topics in this chapter: • • • • • • • • Page Important Features ............................................................................................... 2 Applications.........................................................
randomly-polarized beam. VIS models contain an integral, non-removable hot mirror for blocking unwanted NIR light.
Glossary of VariSpec LCTF Terminology Bandwidth The Full-Width at Half-Maximum (FWHM), measured as the spectral separation between the two points where the filter’s transmission attains 50% of the peak value. The passband center wavelength is the wavelength midway between these two points. VariSpec filters come in a variety of bandwidths, which are set during the design and manufacturing process and are not adjustable by the end-user.
Operator and Equipment Safety It is the responsibility of the purchaser to ensure that all persons who will operate the VariSpec LCTF are aware of the following cautionary statements. As with any scientific instrument, there are important safety considerations, which are highlighted throughout this User’s Manual. Cautionary Statements READ AND UNDERSTAND THIS USER’S MANUAL BEFORE ATTEMPTING TO OPERATE, TROUBLESHOOT, OR MAINTAIN THE VARISPEC LCTF.
Your particular VariSpec LCTF may include additional support documentation from thirdparty vendors. Bear in mind that the VariSpec LCTF may have been modified or customdesigned, so treat such third-party documentation as supplemental material only. In cases where CRi and third-party documentation differ, and you have any doubt as to which applies to your system, contact an authorized CRi distributor or service representative.
VariSpec Hardware Components VariSpec filters consist of either a single module containing both the optics and electronics assemblies or a matched set of two modules. The XNIR-09-20 model, due to its unique optical construction, utilizes two matched sets of optics and electronics modules connected by shielded cables. All VariSpec filters draw power from and are controlled by the Universal Serial Bus (USB) connector of a host computer. Figure 1. VariSpec with 20 mm Optics Figure 2.
Figure 3. LNIR-06-20, Dual VariSpec with 20 mm Optics VariSpec Filter Module • The entrance aperture receives the light, and for VIS models is the side that contains the integral hot mirror. For filters with a blue and silver housing, the entrance aperture is the blue side. • The exit aperture passes linearly polarized light. The orientation is the same or perpendicular to the input polarizer, depending on the design. For filters with a blue and silver housing, the exit aperture is the silver side.
• Init LED flashes during data communication between the electronics controller module and the host computer. • Status LED momentarily flashes Green during power-up and initialization (approximately 30 seconds). The rear panel contains four clearly labeled interface ports (left to right, viewed from the rear). • Optics A is a 26-pin connector for the HD D-sub cable connecting the Optics and Electronics Controller modules.
Male T-Mount Female C-Mount Male C-Mount Mounting Block 52 mm Camera Lens Thread Adapter Hex Key for Set Screws Figure 5. Mounting Block and Adapters for 20 mm Filter Male T-Mount Male C-Mount 52 mm Camera Lens Thread Adapter Female C-Mount Mounting Block Hex Key for Set Screws Figure 6.
10 — Introduction to VariSpec Liquid Crystal Tunable Filters
Chapter 2 Setting Up a VariSpec Filter Topics in this chapter: • • • • • Page Unpacking the VariSpec Filter and Accessories ................................................ 11 Installing the VariSpec Software ....................................................................... 12 Connecting the VariSpec Filter (except XNIR-09-20 models).......................... 12 Connecting XNIR-09-20 Dual-Housing Filter Models ..................................... 13 VsGui Program for Windows XP and Windows 7 ....
Installing the VariSpec Software CRi supplies a Windows-compatible SDK installation CD-ROM with each VariSpec filter. Included hardware drivers are specific to the Windows operating system. However, you may contact CRi if you are interested in drivers for other operating systems. Note that these instructions apply to standard single-housing filter designs. Dual-housing designs have to VariSpec modules. The demonstration software does not support dual module filters.
2. The blinking LED indicates that the filter is initializing and exercising the liquid crystal (LC) elements in the optics module and bringing the filter to a known state. For example, 550 nm in the case of a visible-wavelength (VIS) model. 3. If this is a first time installation, the computer should launch a Found New Hardware Wizard. Click the Next button to proceed. (If the wizard did not start automatically, launch the New Hardware Wizard from the Windows Control Panel.) 4.
Figure 8. 26-pin HD D-Sub cables connect to the VariSpec optics modules and electronics controller modules; USB cables connect to the electronics module and computer 8. If you have not previously used a VariSpec USB filter on your host computer, it will detect the presence of the filter and ask you to locate the USB driver file. If you have the VariSpec CD-ROM in your disk drive, check the box indicating that you wish to have the computer search the CD-ROM for the driver file(s).
VsGui Program for Windows XP and Windows 7 The VsGui demonstration program on the host can be used to verify correct filter operation and demonstrate the filter’s capabilities. 1. When launched (select Start > Programs > CRi > VsGui.exe), the VariSpec Control Panel will appear (Figure 9). Figure 9. VariSpec Control Panel 2. You may initially receive an error message saying that software cannot connect to a COM port (Error Code 104). If this occurs, click OK.
Figure 11. VariSpec Sweep Panel The VsGui program does not interface with commercial image-capture hardware, but the underlying DLL can be used, along with the SDK, to create your own application. If you want to write software to control the VariSpec filter using CRi’s DLL driver, refer to the publication “Programmer’s Guide to VsDrvr”. The most recent revision of this installer program can be downloaded from CRi’s web site at http://www.crii-inc.com.
Chapter 3 Controlling VariSpec Filters Topics in this chapter: • • • • • Page Components of the VariSpec SDK .................................................................... 17 Controlling VariSpec Filters with Direct Serial Commands.............................. 18 Error Codes........................................................................................................ 27 Programming Examples.....................................................................................
National Instruments® LabVIEW™ Sub-VIs CRi provides five sub-VI (virtual instrument) files for basic control of VariSpec filters. The .VI files may be copied to the user library directory within LabVIEW and then accessed from the functions palette to drag and drop into higher-level VI’s. A “VS Getting Started” VI is also supplied, in order to illustrate a way to interconnect the lower-level sub-VI files. MATLAB® M-Files CRi provides a set of MATLAB m-files to control VariSpec filters.
Palette Commands After the VariSpec filter has been initialized, there are two ways to select the passband wavelength. The first is to issue a request to tune to a wavelength using the “W” command. This is the easiest method with current-generation filters. Another method is to define a “palette” of wavelengths.
TABLE 1. Control Modes Mode Description Wavelength or Palette Access Random or Sequential Trigger Source 0 Cycle palette on sync Palette Sequential Sync 1 Reserved N/A N/A N/A 2 Reserved N/A N/A N/A 3 Reserved N/A N/A N/A 4 Wavelength sweep on sync Wavelength Sequential Sync 5 Reserved N/A N/A N/A LED Behavior If the VariSpec filter receives an incorrect communication, the Status LED turns Red and an Error Code is recorded.
The Status-Check character “@” provides various information on filter status. The VariSpec filter responds with a single, printable ASCII character response. Each bit in the response character indicates something about the filter status, listed in the table below. The Busy-Check character “!” tests whether the VariSpec filter has completed all pending commands. If done, it responds with the “>” character. If busy with pending commands, it responds with the “<” character. TABLE 3.
Auto-Confirm format is selected using the “B” command, described later in this section. Upon power-up the VariSpec filter uses the normal format. Table of Commands TABLE 4.
Brief B Command: If is 0, it selects the VariSpec filter’s normal format for replying to queries. If is 1, it selects the brief format. If is 2, it selects the autoconfirm format. At power-up, the default is to use the normal format. In Brief format, the VariSpec filter does not echo the command letter, and omits all leading spaces. Thus the normal reply M 1 becomes, in brief format, 1 In auto-confirm format, replies are made every time a command is received.
In brief format, the response would be: 3 450 550 650 Exercise E Command: exercises the filter times. This places the liquid crystal elements into a known state. An of 3 is sufficient to fully exercise the optics at room temperature. If the filter has been powered off for only a few minutes, an value of 1 can be used. Each cycle takes about 12 seconds.
amount from its present wavelength, upon receipt of an eXecute command or an external hardware trigger pulse in mode 4. At power-up Jump is set to 5.00. The jump step can be any value consistent with the tuning range of the filter, given the specifications. Legal values: determined by filter optics Query reply: present jump size in nm Mode Select M Command: set the Control Mode. Legal modes are 0 (sequential on sync) and 4 (move wavelength step on sync). Mode 0 is sequential.
Note: it is bad practice to query the awake/sleep status, as a sleeping filter will not reply. Version V This can be issued only as a query. It returns the VariSpec firmware revision number and other configuration data, in the following format: v_ _ _ rrr_ _bbbb.bb_ _tttt.tt_sssss where rrr is the firmware revision level; bbbb.bb (no leading spaces or leading zeroes) is the shortest wavelength the filter can tune to, in nm; tttt.
Query reply: temperature of LC elements in optics module in centigrade Escape (ASCII character code 27) This character is processed immediately, with no need for a character. The VariSpec filter stops processing all pending commands immediately. All characters in the communications buffer are erased, and the input buffer is reset. There is a latency of up to 20 milliseconds before the unit returns to the “idle” state.
TABLE 5.
W 500 {tune filter to 500 nm} W 600 {tune filter to 600 nm} W {tune filter to 488 nm, altered spacing is okay} 488 W 900 {wavelength out of range, Status LED lights Red} W ? {what wavelength is the filter currently set at?} W 488.00 {filter stays at the last legal wavelength given} R 1 {clear the Status LED and reset the error condition} Example 2.
Example 3. Cycling through various wavelengths using the TTL Sync port on the XNIR-09-20 Here we define a palette and then use a 10 Hz TTL signal generator at the TTL Sync port to cycle through the palette elements in sequence. {plug VariSpec filter into USB port and wait until initialization is complete} W ? {wait for reply} W 550.
Chapter 4 Frequently Asked Questions & Troubleshooting FAQs I want to clean the glass surface of the VariSpec optics module from fingerprints and other debris. How do I clean it? Use a compressed air can to clean surface dust off the glass surfaces. Hold the can upright so that no freezing-temperature liquid comes out. If the glass surface has fingerprints or other residue, use isopropyl alcohol or commercial lens cleaner. You may also try distilled water or spectroscopic-grade methanol.
models. The actual width of the passband is constant in terms of center wavenumber, but varies in terms of center wavelength such that a center wavelength selected closer to the blue will have a narrower passband width than a center wavelength selected closer to the red. What is the transmission of the filters? The percentage of linearly polarized light, oriented so that maximum transmission is attained, passing through the filter relative to the amount that entered.
Tests (such as CE testing) have shown the enclosure to be resistant to EMI. Nevertheless, exposing the electronics to voltage spikes or sags or a large static discharge can render the filter inoperable or, worse, damage the electronics. I have two XNIR-09-20 filters, can I interchange the optics and electronics? No. VariSpec Optics and electronics controller modules are a matched set with configuration data unique to a particular optics module loaded into the memory of the electronics module.
When I connect the USB cable from the VariSpec filter’s Electronics Controller module to my computer, Windows asks me where 'ftdibus.sys' and 'ftser2k.sys’ are. What can I do? The filter does not seem to be recognized by the Windows operating system. Sometimes the Windows operating system’s Plug and Play feature for new devices does not work entirely seamlessly.
approach to harness reliable data from slides, compared to approaches that use color images acquired on whole-slide digital scanners. The Vectra system incorporates CRi's powerful image analysis software, called inForm™, and CRi's proprietary autofluorescence removal methodology. With this system, you can separate up to five fluorophores from one another and autofluorescence without cross-talk. The system is designed to perform batch processing of slides, up to 200 at a time, or for tissue microarrays.
36 — Frequently Asked Questions & Troubleshooting
Appendix A. System Specifications & Dimensions Operating Specifications Note that these specifications represent typical VariSpec filters as of August 2010 and are subject to change. Parameter VariSpec VIS VariSpec SNIR VariSpec LNIR VariSpec XNIR VariSpec VISR VariSpec NIRR Wavelength range (nm) 400-720 650-1100 850-1800 1200-2450 480-720 650-1100 Bandwidth FWHM (nm) 7, 10, or 20 7 or 10 6 or 20 9 0.25 (best effort) 0.
Mechanical Dimensions (Optics Module) VariSpec 22 mm Aperture Standard Enclosure DWG# MD15284 Figure 12. Exterior of a 22 mm Aperture Enclosure VariSpec 22 mm Aperture Dual-Housing Enclosure DWG# MD15285 Figure 13.
VariSpec 22 mm Aperture Enclosure for the XNIR-09-20 Model DWG# MA20415 Figure 14.
VariSpec Mounting Adapters for 22 mm Aperture Models DWG# MM70226 Figure 15. Stainless Steel Insert — Default, Blank DWG# MM70228 Figure 16.
DWG# MM70227 Figure 17. Stainless Steel Insert — Male C-mount DWG# MM70229 Figure 18.
DWG# MI10408 Figure 19. 52 mm Camera Lens Thread Adapter Standard 22 mm Aperture Filter Mounting Block DWG# MM70225 Figure 20.
VariSpec 22 mm Aperture Enclosure for the LNIR-20-20 Model DWG# MD15369 Figure 21. Exterior of the Unique LNIR-20-20 Enclosure VariSpec 35 mm Aperture Enclosure DWG# MD15470 Figure 22.
Dovetail Spacer DWG# MM70226-LA Figure 23. Dovetail Spacer, Large Aperture Dovetail C-Mounts DWG# MM70228-LA Figure 24.
DWG# MM70227-LA Figure 25. Dovetail, Male C-Mount, Large Aperture DWG# MI10846 Figure 26.
Electronics Controller Module Waiting for ME35036-VS from Paul DWG# ME35036 Figure 27. Electronics Controller Module (for the XNIR-09-20 model only) Optics-to-Electronics Cable DWG# MC30098 Figure 28.
Appendix B. Operating Considerations This section supplies operating considerations with which you should be familiar to maximize the operation of your VariSpec filter. Variation of FWHM with Pass Wavelength The bandwidth of the VariSpec filter is defined as the full-width at half-maximum (FWHM) of the transmission curve. As with all Lyot filters, its bandwidth is constant in wavenumber as the filter is tuned. That means that the FWHM varies with wavelength as λ2.
Response Time versus Temperature The liquid crystal variable retarders set the response time of the filter, and their viscosity varies with the temperature. At 35 ºC, the viscosity is only half its 20 ºC value, allowing faster operation in a warm environment. Elevated temperature use is the single easiest way to improve the response speed. Similarly, if the optics is cooler than 20 ºC, the response time is longer than that given in the Specifications.
Given sufficient heat, delamination may occur. To cause delamination, two factors must be present: heat and stress. Mechanical stress may be produced by the thermal expansion of the LC cells and other components. It seems remarkable, but heat can travel through an entire filter. We must distinguish between heat transmission and optical transmission. The filter acts to stop light passing through it, except for the desired wavelength. Energy is absorbed by the filter’s optics.
5. In the COMx Properties window (Figure 31), select the following settings: Bits per second: 115,200 (9600 for the XNIR09-20), Data bits: 8, Parity: None, Stop bits: 1, Flow control: None. Click the OK button. Figure 31. COMx Properties 6. Select the Properties item from the File menu drop-down list. Click on the Settings tab then the ASCII Setup... button 7.
Appendix C. Legacy Hardware and Software Considerations Optics and Electronics Controller Modules Previous-generation VariSpec filters utilize an RS-232 serial interface. The rear panel of the VariSpec electronics module features an RJ-12 connector and 18VAC 50/60 Hz AC jack. Each filter requires an appropriate power transformer for the country it is to be used in. The US and Japan transformer is an 18V, 880 mA model. An RJ-12 straight-through modular data cable is plugged into the RS-232 connector.
• VSGui Software Developer’s Kit and demonstration executable (revisions prior to 1.2): an obsolete standalone program that will allow a programmer to use a CRiwritten Windows dynamically-linked library (DLL) to control the filter from the CRi-written demonstration program or a user-written program. Current versions will work with both present USB and most legacy RS-232 serial hardware. Contact CRi if you have legacy hardware and/or software and wish to upgrade or purchase new software or hardware.
Appendix D. CRi Software End-User License Agreement The following is an agreement (the “Agreement”) between you and Cambridge Research & Instrumentation Inc., 35-B Cabot Road, Woburn, MA 01801 (“CRi”) for software known as the VariSpec Software Developer’s Kit (SDK) and its accompanying documentation (collectively, the “Software”). By installing and/or using the Software, you agree to the following terms and conditions.
ninety (90) days from the date of delivery. Your exclusive remedy under this Section 6 shall be, at CRi’s option, a refund of the price paid for the Software or replacement of the media on which the Software was provided so long as that media has been returned to CRi under a CRi-issued return authorization. CRi shall have no responsibility to replace media damaged by accident, abuse or misapplication. 7. No Other Warranties.
only in the state or federal courts in New York County, New York State, and you hereby consent to the exclusive jurisdiction of those courts. This Agreement shall not be governed by the United Nations Convention on Contracts for the International Sale of Goods, the application of which is expressly excluded. You may not assign or otherwise transfer this Agreement or any of your rights or obligations therein without the prior written consent of CRi.
56 — CRi Software End-User License Agreement
VariSpec™ Quick Start Guide for a Windows®-based Host Computer MD15473 Rev. B, August 2010 CRi supplies a Windows-compatible SDK installation CD-ROM with each VariSpec filter. Included hardware drivers are specific to the Windows operating system. However, you may contact CRi if you are interested in drivers for other operating systems. These Quick Start instructions apply to standard single-housing filter designs. Dual-housing designs have to VariSpec modules.
VariSpec™ Quick Start Guide for a Windows®-based Host Computer MD15473 Rev. B, August 2010 2. You may initially receive an error message saying that software cannot connect to a COM port (Error Code 104). If this occurs, click OK. Then click the Configure button to open the VariSpec Configuration window (see figure). 3. Click the Auto-detect button to search for the correct virtual COM port. If not found, you can manually select it; choose COM3, COM4, or COM5. 4.
Index A aluminum inserts, dimensions 44 angle-of-acceptance, specification 37 aperture dual-housing enclosure, 22 mm 38 aperture enclosure, 20 mm, XNIR 39 aperture enclosure, 22 mm, LNIR 43 aperture enclosure, 35 mm 43 aperture filter mounting block, 22 mm 42 aperture sizes 31 aperture standard enclosure, 22 mm 38 auto-confirm format 21 awaken command 22 B bandwidth 3 bandwidth FWHM, specification 37 bandwidth, definition 31 brief command 23 brief format 21 busy check 27 busy-check character 20 C camera len
mounting inserts 8 N near-infrared warning 48 NIRR 2 O off-axis performance 3 operating considerations 47 operating temperature, specification 37 Optics A port 8 Optics B port 8 optics response time, specification 37 out-of-band transmittance 3 P palette commands 19 palette select command 25 passband 3 power supply, specification 37 programming examples 28 Q quick start guide 57 R reset command 25 response time 3 response time vs temperature 48 response time vs tuning wavelength 47 S Safety cautionary state
Warranty CRi warrants its VariSpec LCTFs for a period of one (1) year from date of shipment against defects in material and/or workmanship, provided its installation, application, and maintenance are within specifications. Normal wearing parts are excluded. This warranty covers only items manufactured by CRi. CRi will correct, by repair or replacement-at its option and its expense-any proved defects in items of its manufacture, subject to above, provided immediate written notice of such defects is given.
TO PLACE AN ORDER OR RECEIVE TECHNICAL ASSISTANCE For more information, contact CRi or your local authorized CRi distributor: Cambridge Research & Instrumentation, Inc. (CRi) 35-B Cabot Road, Woburn, MA, 01801, USA (Toll-Free US) 1-800-383-7924, (Phone) +1-781-935-9099 (Fax) +1-781-935-3388 (Email) techsupport@cri-inc.com VariSpec, Maestro, and Nuance are trademarks of Cambridge Research & Instrumentation, Incorporated. Adobe and Acrobat are trademarks of Adobe Systems, Incorporated.
