Traditional microscopes have an optimal standard configuration and optical design and focus mainly on decreasing chromatic and spherical aberration. At high magnifications such as 5000x, analyzing a sample will need the help of oil immersion optics or laborious sample preparation for SEM imaging. This kind of high-resolution analysis under high magnification has become easier with the developments in zoom lens optics, digital camera and imaging technologies. However, in ordinary optical technologies, loss of field depth hindered image capture at high magnifications can be a probem. Keyence engineers focused on these kind of issues and ultimately developed the VHX-1000 digital microscope system.
The VHX-1000 Digital Microscope
The VHX-1000 digital microscope from Keyence integrates the optical properties and functionalities of stereoscopes, metallurgical microscopes, and measurement microscopes and thus functions as an imaging, measuring and report-generating microscope. Apart from being equipped with transmitted illumination, slide holders and other instruments used in biological observations, the unit’s key application is in material inspection. The VHX-1000’s versatility received the attention of NASA researchers involved in programs related to Astromaterials Research & Exploration Science (ARES).
Figure 1. NASA Orbital Debris Program
The VHX-1000 from Keyence quickly and easily captures completely focused, high-resolution images for analysis and thus solves the most common problems in modern material inspection.
Increasing the Depth of Field
Limited depth of focus is one of the key problems encountered in material inspection using traditional microscopes, in which the objectives can only focus on a part of the image at a time. Keyence developed an integrated CCD camera and optimally designed optics which work in conjunction to capture sharply focused images having a high depth of focus. This tremendously helps in studying surface structures and details.
Figure 2. Depth of Field
Figure 3. Depth from Defocus Method
For higher magnification observation, a function called “Depth Up” was developed, which can be performed manually or automatically. A processor algorithm captures the focused pixels, integrating them into a fully focused image. 3D measurements such as volume, distance, and angle can also be obtained with the microscope with an accuracy of 1 µm at a magnification of 1000x.
Figure 4. 3D Model
Free-Angle Observation System
In the VHX-1000, the lens is mounted on the arm of a multi-angle viewing stand equipped with an adjustment knob. This arm can be upgraded to precision motorized control. This unique stand enables easy viewing of the sample by manipulating the lens about the target.
Figure 5. Keyence Multi-Angle Stand
Resolution and the Pixel Shift Method
The resolution of the VHX-1000 is excellent for two key reasons:
- High-quality optics and
- An advanced 54 mega pixel (MP), 3CCD pixel shift method.
The VHX-1000 CCD alone is 2.11MP, and a unique method called “pixel shift” is used to obtain higher-resolution images with zero loss of pixel data. Piezo crystal actuators at different sides of the CCD expand and physically shift the CCD in a 3X3 array, capturing images at each new position. This unique method creates nine sub-pixels, thus increasing the CCD image’s pixel value from 2.11 to 18MP.
Figure 6. Pixel Shift VS Extrapolation
The pixel shift method in the VHX-1000 shifts the CCD under a Bayer filter, thus exposing each pixel to red, green and blue color filters and increasing the image quality to that of a 54MP 3CCD camera. The entire pixel shift process takes place in less than 5 s.
The VHX from Keyence integrates the lighting with the lens, so that the target in the field of view is always under optimal lighting. Apart from having a series of lighting adapters for the lenses, it also uses several software functions to obtain optimum brightness and contrast for a specific sample. The user can choose from an array of nine different reproducible lighting scenarios with combinations of edge enhancing, color enhancing, or contrast enhancing lighting to find out the most suitable lighting for the application.
Figure 7. Nine Reproducible Lighting Scenarios
High Dynamic Range scenario is the most important of the lighting scenarios. This function first captures multiple images at several brightness levels and then integrates them into one single image with extremely high levels of color gradation.
Figure 8. High Dynamic Range
Replacing Eye-Pieces with a 17” Monitor
The VHX-1000 digital microscope from Keyence has an in-built 17” monitor which allows viewing the live sample by multiple users at the same time. The image can be paused or recorded and viewed later and the screen can be split into four sections for side-by-side comparisons and vertically or horizontally as well.
Figure 9. Integrated Monitor
The VHX-1000 from Keyence combines both 2D and 3D measurement capabilities. 2D measurements such as radius, distance, angle, or area and 3D measurements such as volume, angle, distance, or profile can also be made using the VHX-1000.
Figure 10. 2D and 3D Measurement Tools
Lenses of the VHX-1000 digital microscope range from 0.1x to 5000x magnification and are easily interchangeable. Each lens belonging to the Real Zoom lens series offers six different magnifications within a single lens. The VH-Z20R lens has 20x to 200x magnification. These lenses also have telecentric ranges, thus eliminating errors in measurement and calibration.
Figure 11. Lenses from 0.1x-5000x Magnification
Real Time Image Stitching
The VHX-1000 from Keyence has real-time image stitching up to 10,000 X 10,000 pixels, which extends the viewing area of even lenses having the highest magnification. The VHX stitches a 2D image in real time and expands the viewing area by about 50 times using an advanced pattern matching algorithm. The VHX-1000 can stitch 3D images also up to 10,000 x 10,000 pixels.
Figure 12. Image Stitching
Integrated Documentation and Report Generation
The ability of VHX to perform full observational documentation and report generation is an excellent time-saver. The embedded file properties are lens/magnification used, a time and date stamp, and any other desired information. Several commenting tools for image labeling, comparison, or to highlight certain features on the target are also available. Users can save the image with or without measurements and comments and a Report Generation tool helps place the image in a report format.
Figure 13. Report Generation
Standard Microsoft Word or Excel report templates can also be uploaded. A report can be instantly generated in the desired report template, which saves analysis and reporting time.
File Share and Transfer
Files can be exported using one of the eight USB ports on the VHX. Images can be saved from the VHX to a network folder. There is an option to burn files to DVD/CD-R. Several departments in different locations can access the VHX images using Internet Explorer or the communication software present in VHX.
Major applications of the VHX series of digital microscopes from Keyence are the following:
- Research and development
- Failure analysis
- Quality inspection work
The VHX also find applications in the following key industries:
- Medical Devices
- Forensic Inspection
Figure 14. VHX Applications
In addition to these sectors, the VHX digital microscope from Keyence is used in the following areas:
- Pharmaceutical - pills/tablets, powders, contaminants, packaging
- Aerospace - coatings, materials, fibers, micro-cracking
- Chemical - minerals, household products, tribology
- Biological/Entomological - insects, bone, teeth, skin, wet mount slides
The VHX-1000 digital microscope from Keyence has state-of-the-art imaging and measurement capabilities. It integrates advanced functionalities into a single unit, by combining the capabilities of stereoscopic microscopes, metallographic microscopes, SEMs, and measuring microscopes. The VHX-1000 tremendously reduces the time required for observation/documentation and provides extremely high resolution images, which was a real challenge for conventional microscopes.
Figure 15. VHX-1000 Digital Microscope
With the rapid development of factory automation and enhanced focus on inspection and R&D tools, KEYENCE, as the leading supplier of sensors, measurement devices and microscopes, is developing and manufacturing innovative and reliable products that meet customer requirements in every manufacturing industry.
This information has been sourced, reviewed and adapted from materials provided by KEYENCE.
For more information on this source, please visit KEYENCE.