Non-Contact Thickness Measurement

Transcription

1 Non-Contact Thickness Measurement It's Our Business to be Exact! Reliable accuracy and exceptional repeatability for the most demanding thickness testing applications. Applications CONTACT AND INTRAOCULAR LENSES: Measures center thickness and sagittal height MEDICAL BALLOON CATHETERS: Measures wall thickness of body, neck, and cone PLASTIC FILMS, LAMINATES, GLASS, AND ADHESIVES: Measures single or multi-layer thickness MEDICAL TUBING: Simultaneously measures wall thickness, outer diameter, and inner diameter Key Features Measures thickness from one side without damage or deformation. All layers and total thickness are measured simultaneously. Highest accuracy of up to ± 0.1 µm. Exceptional long-term measurement repeatability as good as ± 0.02 µm. Continuous calibration with a built-in intrinsic standard of length. Traceable to NIST standards. Broad measurement range of 35 µm to 8 mm. Straightforward operation and versatile integration. Rugged design for manufacturing environments.

2 Thickness Measurement Using Light - The Bristol Advantage The Optical Thickness Gauge from Bristol Instruments uses the unique properties of light to accurately measure thickness. To make a measurement, light is directed onto the material under test. Reflections from every surface and layer interface are collected and then analyzed by an optical interferometer. This very precise optical ruler measures the difference in length travelled by each reflection to determine total thickness and the thickness of each layer. Single-Layer Measurement Light from LED Reflections from a single-layer material Sample under test A single layer material will return two reflections, one from each air/material interface. The peaks in the display represent the relative positions of the two reflections. The difference in the positions of the two peaks gives the material thickness. Multi-Layer Measurement Light from LED Reflections from a multi-layer material Sample under test A two-layer material will return three reflections, one from each air/material interface and one from the internal material interface. The peaks in the display represent the relative positions of the three reflections. The difference in the positions of the three peaks gives the thickness of each layer, as well as the total material thickness. BRISTOL INSTRUMENTS, INC. 2

3 Reliable Accuracy and Exceptional Repeatability The offers the highest performance available to ensure the most meaningful test results. Continuous calibration with a built-in standard and a unique interferometer design guarantees that the measurement accuracy and repeatability is maintained year after year. HIGHEST MEASUREMENT ACCURACY The model 157 is the most precise, measuring thickness to an accuracy of ± 0.1 µm (± mils). The model 137 is a lower-priced alternative with an accuracy of ± 1 µm (±.04 mils). LONG TERM REPEATABILITY, AS GOOD AS ± 0.02 µm (± mils) Defined as the standard deviation of measurements taken over a 60-minute period without averaging. Ideal for the detection of thickness changes as small as 0.04 µm (0.002 mils). CONTINUOUS CALIBRATION ENSURES CONFIDENCE IN THE MEASUREMENTS Every measurement is referenced to a HeNe laser which has a wavelength that is recognized by the US National Institute of Standards and Technology (NIST) as an intrinsic, invariant standard of length. Eliminates the need for external calibration or any user intervention. TRACEABLE TO A KNOWN STANDARD For added confidence, each Optical Thickness Gauge is rigorously tested with a set of three different NIST certified gauge blocks to verify performance. Model 157 Optical Thickness Gauge Measurement Data (Gauge block certified by NIST to have a thickness of µm) Thickness (µm) Minimum µm Maximum µm Average µm Standard Deviation µm Time (Hours) BRISTOL INSTRUMENTS, INC. 3

4 Straightforward Operation Operation of the is straightforward, making it easy to get reliable measurement data every time. 2-Axis Angular Adjustment Mount Used to align the optical probe to the sample. Z-Axis Linear Stage Used to adjust the focus of the optical probe. X- and Y-Axis Linear Stages Used to position the sample under the optical probe. MEASUREMENT PROCESS (1) The optical probe is aligned to the material under test using common commercially available positioning components. (2) Light from a superluminescent LED (SLED) is directed onto the material surface through the optical probe. (3) Reflections are collected by the optical probe and returned to the system s interferometer for analysis. (4) Thickness data is calculated using an on-board digital signal processor and transferred to a PC using USB or Ethernet interface. (5) Bristol s Windows-based Opti-Cal software is used to control measurement parameters and report thickness data in a variety of formats. ALIGNMENT OF THE OPTICAL PROBE The probe is positioned and aligned using a simple 4-step process. Angular (1) Rough Align The 2-axis angular adjustment mount is used to align the optical probe so that it is perpendicular to the sample surface. (2) Position The X- and Y-axis linear stages are used to pinpoint the desired measurement location on the sample surface. A visible beam is emitted from the optical probe to facilitate this process. (4) Optimize The 2-axis angular adjustment mount is used to maximize the heights of the reflection peaks on the measurement display. (3) Focus The Z-axis linear stage is used to set the optical probe approximately 1.5 inches away from the sample surface. BRISTOL INSTRUMENTS, INC. 4

5 Convenient Measurement Reporting The reports measurements using its Windows-based Opti-Cal software. Thickness data for the material under test is reported, and the interferometer signal is displayed so that the measurement parameters can be optimized. MEASUREMENT DISPLAY Outer Diameter Inner Diameter Wall Wall Thickness Thickness The Reflection Peaks Graph displays the signal that results from the reflected light from all the surfaces of the material under test and all the interfaces within the material under test. The figure above shows the results of the measurement of a glass tube. The reflections from the air/glass interfaces generate the peaks shown in the graph. The differences between the positions of the peaks provide information about the top wall, inner diameter, bottom Top Wall wall, and outer diameter. The Data Table reports the thickness information of up to 15 different layers. This includes individual layer thickness, total thickness by layer, and measurement standard deviation. Units of millimeter (mm), micrometer (µm), and millionth of an inch (mils) can be chosen. Every measurement can be displayed, or a running average can be calculated automatically. Air Gap Bottom Wall TREND DISPLAY A trend feature is available to provide a graphical trace of thickness over time. This is particularly useful for real-time analysis of a manufacturing process. BRISTOL INSTRUMENTS, INC. 5

6 Flexible Integration for Manufacturing Environments The is ideal for both the research scientist and the manufacturing engineer because its versatility enables its use in virtually any application. INTERFACING OPTIONS The instrument can be connected directly to a PC using either a USB or an Ethernet interface. The Ethernet interface can be used to connect to a network. Multi-user interfacing allows up to eight network-connected clients direct access to real-time measurement data. Automatic reporting can be done using LabVIEW,.NET, or custom programming thereby eliminating the need for a dedicated PC. OPTICAL SWITCH CAPABILITY A fully integrated and synchronized optical switch allows for as many as eight test stations with a single instrument making manufacturing applications more cost effective. BRISTOL INSTRUMENTS, INC. 6

7 SPECIFICATIONS 157/137 Series MODEL THICKNESS MEASUREMENT Method Range 1 Non-contact optical interferometry 35 µm - 8 mm ( mils) Accuracy 2, 3 ± 0.1 µm ± 1.0 µm Repeatability 4, 5 ± 0.02 µm (without averaging) ± 0.05 µm (without averaging) Traceability Verified with NIST certified gauge blocks Display Resolution 0.01 µm Units MEASUREMENT RATE INSTRUMENT INTERFACE COMPUTER REQUIREMENTS 6 mm, µm, mils 20 Hz USB and Ethernet with Opti-Cal Windows-based display software Ethernet can be used for network connection allowing instrument access to up to 8 clients Library of commands for LabVIEW,.NET, and custom programming PC running Windows 7, 8, or 10, 1 GB available RAM, USB 2.0 (or later) port, monitor, pointing device OPTICAL SWITCH 7 Capacity Switch Time 8 Integrated 1 x 8 fiber switch 1 ms ENVIRONMENTAL 9 Warm Up Time Temperature Pressure Humidity None 15 C to +30 C (-10 C to +70 C storage) mm Hg 90% R.H. at + 40 C (no condensation) DIMENSIONS AND WEIGHT Dimensions (H x W x D) Weight POWER REQUIREMENTS WARRANTY 3.5" x 17.0" x 15.0" (89 mm x 432 mm x 381 mm) 17 lbs ( 7.65 kg) VAC, Hz, 80 VA max 3 years, includes parts and labor (1) (2) (3) (4) (5) (6) (7) (8) (9) Physical thickness assuming an index of refraction of 1.5. Physical thickness is equal to optical thickness divided by the index of refraction. Defined as measurement uncertainty, or maximum thickness error, using a coverage factor of 3 providing a confidence level of 99.7%. Uncertainty over the entire operational environmental conditions. Standard deviation for a 60 minute measurement period. Dependent on the reflectivity of the material under test at the probe wavelength of 1.3 µm. Specification is given at 4% reflectivity. When reflectivity is lower, repeatability is reduced to a worst case of about ± 0.15 µm. Required for initial optical probe alignment and use with the Opti-Cal Windows-based display software. Not required for measurement. Integrated fiber optic switch included with models and Switch time has no effect on the measurement rate of the and systems. Characteristic performance, but non-warranted. Bristol Instruments reserves the right to change the detail specifi cations as may be required to permit improvements in the design of its products. Specifi cations are subject to change without notice. BRISTOL INSTRUMENTS, INC. 7