Thanks to a combination of high-quality optics and advanced digital imaging technology, today’s newest digital microscopes provide efficient solutions to a variety of common microscope challenges faced by users of conventional optical and digital microscopes. The following represent 10 conventional microscope issues and 10 solutions made possible with current digital microscope technology.

Figure 1A. When performing inspection with a traditional microscope, it is often impossible to image the inner pattern of the circuit board.

Issue 1: Specific Details Need to be Seen on Challenging Samples.

In many imaging cases, a sample with low contrast cannot be clearly observed. Even after enlargement, it can be difficult to clearly observe sample surface conditions with low reflective difference and low contrast. In other instances, glare caused by halation can disturb the sample surface, making it difficult to conduct a clear observation (Figure 1A). To eliminate this glare, illumination needs to be carefully adjusted, which can require considerable time and may still not produce satisfactory results.

Solution: Optimized Digital Imaging Processing

The advanced digital image processing used by today’s digital microscopes allows clear observation of surface conditions that are normally difficult to observe using an optical microscope. For example, the HDR (High Dynamic Range) function offered by modern digital microscopes such as the Olympus DSX series combines several images taken at different exposures, enabling optimal observation, even with low-contrast images (Figure 1B). With HDR, samples that previously may have required multiple pieces of equipment for precise observation can be clearly observed with a single system. The DSX also eliminates glare with WiDER, a proprietary image processing system that takes care of high-contrast problems with one simple click. WiDER works effectively with live images without requiring troublesome adjustments to illumination.

Issue 2: A Large Sample Area Needs to be Observed in High Resolution.

With conventional microscopes, it is difficult to view an entire sample at high resolution. As magnification is in creased, the observation field becomes narrower, and it becomes very hard to obtain an overall image of the sample.

Figure 1B. Using a digital microscope, a live image can be displayed using HDR observation to combine multiple images with different exposure times. (Image created using the Olympus DSX510)

Solution: Panoramic Imaging

With new digital microscope technology, nothing is “outside the field of view.” With panoramic imaging, today’s latest digital microscopes can automatically stitch images into one seamless view by moving the stage, obtaining high resolution across all image areas, even with large samples. Where conventional microscopes reduce field area with increases in magnification, panoramic imaging maintains the original field while delivering close-up clarity—in 2D, 3D, extended focus, or any combination of the three.

Issue 3: All Areas of an Uneven Surface Need to be in Focus at the Same Time.

With conventional microscopes, it is sometimes only possible to achieve clear focus on part of a sample that has an uneven surface. Due to limitation of depth of focus, the more the operator increases the magnification, the shallower the depth of focus can become, making it more difficult to achieve clear focus on the entire sample.

Solution: EFI (Extended Focal Image)

With EFI (Extended Focal Image) capability, microscopes like the DSX can obtain a clear, in-focus image of an entire sample with one click—no matter how uneven the surface. EFI extracts and combines focused images by simply moving the point of focus up or down, maintaining focus across the entire sample surface area and allowing precise inspection of uneven surfaces.

Issue 4: Sample Features Need to be Determined, Characterized, and Measured in 3D.

With an optical microscope’s plain view observation, it is difficult to determine the exact features of a dimensional sample based on a 2D image. In some cases, the operator has no choice but to make their best guess as to height differences in a sample or whether sample unevenness is concave or convex.

Figure 2. 3D image of surface capacitor. (Image created using the Olympus DSX510)

Solution: 3D Imaging

With one click, today’s digital microscopes can image a sample in three dimensions, allowing examination from any angle and an accurate view of the sample (Figure 2). And with accurate height information, detailed 3D images allow sample features or unevenness to be viewed and measured. Height differences and volume can also be measured, making it easier to obtain accurate sample analysis.

Issue 5: Operators with Varying Skill Levels Need to Perform Similar Tasks.

With traditional optical microscopes, switching between observation modes can mean a sequence of complicated operations and adjustments. Without the right level of expertise, it can be challenging to ascertain the image characteristics one needs for the task at hand. Changing observation modes often requires the adjustment of aperture stop and illumination, the insertion of special filters, and more.

Solution: One-Click Observation Modes

With one simple click, today’s digital microscopes let any operator—regardless of skill level—choose the observation mode that’s ideal for their application. All a user has to do is select their optimal image from a list of captured image choices, and observation mode is adjusted based on that selection. This means that any operator, from beginner to expert, can conduct the same types of high-level observation.

Issue 6: Reproducible Measurements Are Needed from Multiple Operators.

With conventional microscopes that require many adjustments and settings, it can be difficult for multiple operators to conduct observations under identical conditions. These conditions can begin to vary depending on the operator and their particular method, which can cause major differences in images. This can lead to serious problems with R&D, QA/QC, or material testing.

Solution: Digital Repeatability

With a fully digital microscope, all image acquisition and observation conditions – including stage coordinates, observation method, etc. – can be saved and referenced at any time. Any operator can then easily repeat all inspection and measurement methods, guaranteeing observation under the same conditions and settings. Image capture conditions can be recalled with one click.

Issue 7: Optical-Quality Imaging is Needed from a Digital Microscope.

The perception still exists that digital microscopes provide ease of use, while optical microscopes produce clearer images with natural color and higher resolution. Many operators still divide their microscope usage between the two. This wastes time and does not allow continuity of observation between digital and optical images.

Solution: Dedicated Lenses

Advanced digital microscopes utilize dedicated lenses that combine high NA, long working distances, well-controlled aberration, and evenness of light intensity. These lenses are then combined with Full HD cameras and HDR digital processing, minimizing glare and ensuring real color reproduction. Flare and distortion are eliminated, previously unheard of with digital microscopes.

(Left) Figure 3A. MEMS device image made with brightfield observation mode; (Center) Figure 3B. MEMS device image made with darkfield observation mode; (Right) Figure 3C. MEMS device image made with MIX (brightfield plus darkfield) observation mode. (Images created using the Olympus DSX510)

Issue 8: Guaranteed Measurement Accuracy is Required from a Digital Microscope.

In general, traditional digital microscopes offer no clear accuracy guarantees. Operators have no way of assuring the scope of error of the equipment they are using.

Solution: Telecentric Optics

Advanced digital microscopes use the same telecentric optics utilized in measuring instruments, which eliminates variation in measurement results. If the point of focus is changed, there is no change in the size of the observation target. This guarantees no variation between operators, allowing measurements to be conducted under extremely stable conditions.

Challenge 9: Varied Observation Techniques Require Different Lens Setups.

Standard digital microscopes feature a lineup of lenses for various uses—different observations require the switching out of lenses. This creates the time-consuming necessity of conducting lens replacement between different types of samples and different types of observations. Numerous steps are required to find the optimum lens setup for each application.

(Left) Figure 3D. MEMS device image made with DIC observation mode; (Right) Figure 3E. MEMS device image made with PO observation mode. (Images created using the Olympus DSX510)

Solution: Variety of Observation Modes with One Lens

Today’s newest digital microscopes are equipped with an objective lens that can be used for a wide variety of observation methods, enabling the creation of optimal viewing conditions without replacing a lens. Switching between observation modes is as simple as one click (Figures 3A-E).

Issue 10: Magnification Adjustments Require Manual Calibration.

Many digital microscopes require manual calibration every time the magnification is changed. If images or measurements are taken using the wrong calibrations, the magnification indication and measurement values will also be wrong, and the whole process will have to be performed again.

Solution: Automatic Magnification Recognition

To reduce human error, today’s newest digital microscopes offer automatic magnification recognition, with a motorized zoom system that displays the setting conditions of the mainframe. Changing lens magnification automatically changes the magnification setting, eliminating the opportunity for measurement error. When the zoom magnification is changed, the current magnification and image area information is also updated, further reducing errors in magnification indication and in measurement.

Today’s latest digital microscopes offer fast, efficient observation; simple, intuitive operation; a wide variety of image capturing methods; and superior imaging and measurement results. Options include EFI and 3D imaging, panoramic image capturing, movie capturing, and programmed image capturing—all within an interface that’s as simple to use as a tablet or smartphone.

This article was written by Robert Bellinger, Applications Specialist, Olympus Scientific Solutions America (Waltham, MA). For more information, contact Mr. Bellinger at This email address is being protected from spambots. You need JavaScript enabled to view it. or visit http://info.hotims.com/61063-200 .


Photonics & Imaging Technology Magazine

This article first appeared in the July, 2016 issue of Photonics & Imaging Technology Magazine.

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