Mitutoyo offers a higher resolving power version of the M Plan APO line, known as M Plan APO HR. Thanks to generous loan from a friend, not only do I have access to new M Plan APO HR 5X 0.21 (HR5X) to test the image quality but I also compare the HR5X to the standard Mitutoyo M Plan APO 5x 0.14 (MP5X), and a QV-Objective HR (QVHR) 2.5x 0.21 (also on loan from a friend), all at the same time!
This is something you don’t see this everyday, a brand-new in-the-box Mitutoyo HR5X!
Does the higher resolving power of the HR5X make a big difference in image quality? What about CA correction like? How large is the image circle compared to a standard M Plan 5x?
Is the QVHR lens really a pushed down HR5X lens in a different barrel? The QVHR objective is made for use with Mitutoyo Quick Vision (QV) metrological microscopes. The main drawback to the QV objectives I’ve tested has been poor coverage since they were designed to cover small CCD sensors around 8mm Ø with a standard 100mm tube lens. Using a longer 200mm FL tube lens the image circle should become larger. With infinity-corrected objectives you can change the tube lens focal length to create lower or higher magnification ratios. A shorter tube lens results in less magnification and a smaller image circle while a longer tube lens results in more magnification and a larger image circle. For this test I will use the QVHR on a 200mm tube lens.
On the left, the M Plan APO 5X, M Plan APO HR 5X in the center, and the QV-objective HR 2.5X on the right.
All of the lenses tested here were purchased by or loaned to closeuphotography.com, without any discount or commission from any person unless noted otherwise. The M Plan APO HR 5x and QV-Objective HR (QVHR) objectives are on loan from friends for this test. Closeuphotography.com does not use affiliate links that generate a commission when the visitor clicks on a link to buy something. This is not a fan page either, this product was not given to me, I was not paid to write this, nor did the manufacturer or distributor loan me this lens for this review.
Special thanks to all my friends and colleagues that donated their time for suggestions and proofreading this test!
KEY FEATURES OF THE APO HR 5x
High resolving power
Wide 30mm Ø field (30mm is considered beyond ultra-wide in microscopy)
Aberration free, apochromatic design
Infinity corrected
Plan corrected for a flat image field
Long working distance
Designed to be used without a cover-slip
HR OBJECTIVE COVERAGE
The other 5x HR objectives on the market, the Edmunds and Optem HR 5x, are not APO corrected, Plan corrected, and have a tiny image circle. With an 11mm optical field, neither of the Edmunds/Optem pair would cover a point-and-shoot 1" sensor. The super-wide 30mm field of the HR5X makes it quite unique since there is almost no competition to speak of, and as a matter of fact I can think of only one other HR 5x objective that can compete, the Qioptiq mag.x LD-Plan Apo 5x/0.20.
| Mag / NA | Field Diameter | APO | Plan | Price | |
|---|---|---|---|---|---|
| Edmunds EO High Resolution | 5X / 0.225 | 11mm | No | No | 1,990 USD |
| Optem High-Resolution | 5X / 0.225 | 11mm | No | No | 1,990 USD |
| Mitutoyo M Plan APO HR | 5X / 0.21 | 30mm | Yes | Yes | 4,750 USD |
| Qioptiq mag.x LD-Plan Apo | 5X / 0.20 | 25-57mm | Yes | Yes | 8,630 USD |
Notes:
The mag.x coverage is designed to changed as needed by the use of different focal length tube lenses. The system standard is 250mm and Qioptiq figures are really conservative, the coverage is more like 38-40mm with a short 240mm tube lens.
The QV HR objective in not included the table since I cannot locate a price. If you have access to that data let me know and I can add it.
For reference Sony APS-C sensors need a 28mm Ø image circle, full frame, 43mm Ø image circle for complete sensor coverage.
HR5X Image Samples
Click on the image below to view a larger version in a Lightbox viewer, the size of the image sent to your device is based on the screen size. To see an image in a new browser tab, right click, or two-finger press, and select Open in a New Tab or New Window from the menu. To save an image, right click, or two-finger press, and select Save Image As to save and view the image full size image in your favorite imaging app.
The fine details and micro-lettering that the HR5X can resolve on this disk is incredible. This image was made with Pixel Shift Multi Shooting mode and is not a focus stack. Click on the image to see a larger full-size 2500 pixel version.
Left to right, central crop area, 28mm (APS-C) corner crop in the center, and full frame corner (lower left area of the wafer).
The HR5X produces tack sharp fine details without any trace of chromatic aberrations anywhere in the frame. This Dallas Semiconductor disk is one of my most used wafers and this is the best image quality I’ve ever seen at 4 or 5x. Due to the high contrast of this wafer, all but the very best lenses will show color fringing, but the HR5X shows no chromatic aberrations at all. This wafer image was made in Pixel Shift Multi Shooting mode, and not using any focus stacking.
Butterfly wing scale section (Hypolimnas monteironis) focus stack image of 130 files. The HR5X scale details below are fantastic.
Setup details:
Camera: Sony α7R IV (A7R4), also called the Sony Alpha ILCE-A7R IV (A7R4)
Tube lens: Raynox DCR-150 (208mm) mounted normally, that is label towards subject, and 50mm extension between objective and TL.
Sensor size: Full Frame. 35.7mm x 23.8mm. 42.91 mm diagonal. 3.76 micron sensor pitch
Flash: Godox TT350s wireless flash x 2 with one Godox X1s 2.4G wireless flash transmitter
HR 5X PROS AND CONS
What I really like:
Incredible sharpness
0.21 numerical aperture
Complete lack of LoCAs or LaCAs
Extremely consistent image quality covering a full frame sensor
Standard Mitutoyo M26 x 36 TPI mount
Awesome image quality even when pushed down or pulled up (magnification)
What I can do without:
The highly reflective polished silver body, a less reflective matte finish would be better
Some flare can be an issue under certain parameters with off-axis lighting
The screw-on objective front cover looks like it is limiting the image circle diameter when pushing the magnification down
MITUTOYO M PLAN APO HR 5X 0.21 OBJECTIVE SPECIFICATIONS
Mitutoyo Part Number: 378-787-4 M Plan Apo HR 5x
Official name: M Plan Apo HR 5X/0.21 high-resolving bright-field long working distance objective lens
Objective type: Industrial inspection and machine vision systems
NA and Nominal Aperture: 0.21. Nominal aperture is f/1.98, effective aperture is f/11.9 at 5x.
Focal length: 40mm
Parfocal length: 95mm (distance from the base of the thread mount to the subject plane)
Working Distance: 25.5mm (34mm for the standard M Plan )
Correction: Plan-Apochromat (APO) ( plan correction to produce a flat image across the field) (An APO is corrected for four (dark blue, blue, green, and red) or more colors chromatically and four colors spherically)
Resolution: 1.3 µm at the reference wavelength of λ=0.55µm (green)
Mounting Threads: M26 x 36TPI or M26 x 0.706mm JIS B-7141-1988
Coverage: 30mm OFN (Optical Field Number), 30mm image circle Ø
Source: made in Japan
Manufacturers price: $4750 USD MSRP in the US.
Used market prices: not enough information, too few units sold on the used market
5X image circle sharpness Test: M Plan APO vs M Plan HR vs QV HR
This section of the test is to check coverage and sharpness with the three objectives. For best results I recommend downloading the files and comparing them side-by-side or a stack them for an A-B type type comparison using a image viewing app.
I’ve posted additional results on another test page to keep things simple and clean here on this main page, you can follow the link to the new HR vs MPlan sharpness test here: https://www.closeuphotography.com/hr-vs-mplan-test
Resolution and NA
The biggest difference between HR and the standard M Plan APO, other than the price, is the numerical aperture (NA). The standard M Plan has an NA of 0.14 and a nominal f/2.9, the HR5X has an NA of 0.21, or f/1.9. At 5x the effective aperture (EA) of the MP5X is f/17.9, but the MP5X is f/11.9. This 1.5 stop gain will make a difference since a larger aperture = higher potential resolution. This larger aperture means less sharpness loss due to diffraction, and a gain in resolving power from 2 µm down to 1.3 µm.
Click on the image below to view a larger version in a Lightbox viewer, but this will only be the largest size image if your screen/window is large enough. The size of the image sent to your device is based on the screen size. To see an image in a new browser tab, right click, or two-finger press, and select Open in a New Tab or New Window from the menu. You can also right click, or two-finger press, and select Save Image As to save and view the image full size.
Green test wafer with ruler for scale.
Center, 28mm image circle corner, and full frame corner areas outlined.
Mitutoyo QV Objective HR 2.5X 0.21 @ 5X
The QVHR image quality in the center is just about perfect without any hint of CAs. The QVHR objective was tested with a f=200mm tube lens (Raynox DCR-150) to increase magnification up to 5x and at the same time to increase coverage with a larger image circle. Unfortunately for some reason the image circle did not improve. As tested the QVHR did not cover a 28mm (APS-C) image circle. The falloff is not due to field curvature and reversing the DCR-150 tube lens only made the issue worse.
The main difference between HR5X and QVHR is one of image circle size. The QV unit is designed to cover a very small CCD video camera sensor. The QV scope that I have had here in the office used a tiny sensor with an image circle Ø of only 8mm! I’ve been told by QV objective owners that other models do have a normal 30mm image circle but I have not tested any of these.
Mitutoyo M Plan APO 5X 0.14
MP5X center was sharp and detailed, with only just the slight hint of CAs in the center and 28mm IC crop area (APS-C). The full frame corner area was softer and did show some CAs. The Raynox DCR-150 tube lens was used with the MP5X. Full tube lens setup details are below.
Mitutoyo M Plan APO HR 5X 0.21 + Raynox DCR-150
HR5X results are fantastic, even better than I expected when paired with the Raynox DCR-150. Sharpness was very consistent from center to the far edge of the A7R4 sensor. Center and 28mm IC crops have zero CAs, there were some very slight CAs in the corners, but coverage is great and field was very flat. An amazing performance overall. Looking at the full frame corners its almost as if the image circle kept going and going.
Mitutoyo M Plan APO HR 5X 0.21 + Thorlabs ITL200
The ITL200 full frame results are one of the biggest surprises of this test. Image quality is about as good as it gets from center to 28mm IC, and very good in the corners. When I first saw the results in the corners I had to check to make sure the A7R4 was not in manual APS-C crop mode! The ITL200 was used in reverse for this test and the magnification is slightly less than the Raynox DCR-150 (208mm). This tube lens was not designed for an image circle large enough to cover a full frame sensor.
HR5X Pushed down to 4.5X on full frame sensor
The results using a Schneider Componon-S 5.6/180 to push the HR5X down to 4.5x were good, but there were a bit more CAs than I expected. Overall the sharpness is awesome all the way from center to corner. Stopping the 180 down did not improve CAs. You can find full setup details below the results.
HR5X Pushed down to 3.8X on full frame sensor
For 3.8x I used the Schneider Componon-S 5.6/150 to push the HR5X down and the results are really good with less CAs than the 180mm.Sharpness and image quality was very good overall.
HR5X Pushed down to 3.4X on full frame sensor
The Schneider Componon-S 5.6/135 pushes the HR5X down to 3.4x. The results in the center and the APS-C crop area are both excellent. Very sharp with well controlled CAs. The full frame corner crop is a bit of a problem where the results are not as good, the image quality drops off due to veiling glare. I wasted a lot of time trying to fix the issue thankfully I did eventually find the issue.
As it turns out the issue is with the objective’s front screw-on cover or shroud. There is flare bouncing off the disk and reflecting into the interior of the lens at an angle. Stopping the lens made things worse and at the same time made the issue easy to see. This is not a defect, since I’m 100% sure this objective works perfectly fine with co-axial lighting or a ring-light even, but with a highly reflective subject and 45 degree side light, you might see an issue with flare.
To illustrate the flare issue, I was able to recreate the effect with a flashlight. In the first image you see the LCD on the back of the A7R4 with the tube lens stopped down to f/32. I placed a flashlight to the left left and out of the frame. You can see the flare on the right, this hot spot was causing veiling glare.
The second image shows the silver ring at the front of the lens is the backside of the front cover. The front cover reflects light into the objective hitting some interior part, causing the flare issue as seen on the left. The image was made with my phone pointed inside the objective, without any tubes or adapters attached. Flare is present on both sides when using two flash units.
To combat the flare I tried two different style shrouds, the first was one made of Protostar light-trap material that was the same size as the objective barrel. No noticeable effect on the flare. In the third image you can see my second attempt with a rolled strip of Protostar sticking out of the end of the HR5X. It is sitting inside the front cover resting on the front element. Also no effect on the flare issue. Lengthening the shrouds didn’t help at all instead they only blocked light from hitting the subject.
Test Setup Details
Camera: Sony α7R IV (A7R4), also called the Sony Alpha ILCE-A7R IV (A7R4)
Sensor size: Full Frame. 35.7mm x 23.8mm. 42.91 mm diagonal. 3.76 micron sensor pitch
Flash: Godox TT350s wireless flash x 2 with one Godox X1s 2.4G wireless flash transmitter
Vertical stand: Nikon MM-11 with a Nikon focus block
The sharpest frame was then selected out of a stack of images made in 2 micron steps. Separate images were selected for center, edge, and corner if needed. Each image was processed in PS CC with identical settings with all noise reduction and lens correction turned off, all settings were zeroed out (true zero) and the same settings were used for all of the images. All images shown here are single files only and have not been stacked.
Test results
The HR5X image performance exceeded my expectations in every category, with the biggest image circle I’ve seen out of any microscope objective! The HR5X has a higher level of chromatic correction than the standard M Plan APO, with higher resolving power over a larger image circle! The HR5X image quality is easily the best Mitutoyo objective that I have ever used. The HR5X is more expensive than the normal MP5X but I think the higher resolving power, better chromatic correction, plus the larger image circle are worth it.
The Mitutoyo M Plan APO HR 5X 0.21 (HR5X) is highly recommended.
After this test I would like to test the HR5X again with the front cover removed, I think the corner performance and sensor coverage would improve. Maybe I can find a used HR5X and remove the cover, the HR5X in this test is a brand new copy on loan, so forcing the hood off is not going to happen with his lens.
Tube Lens Setup notes
HR5X
Raynox DCR-150 +4.8: normal mount tested best (lens label towards objective), reverse mount performance was worse. 50mm objective separation was best. Minimal and 75mm separation was worse.
Thorlabs ITL200 f=200 tube lens: reverse mount tested best (smaller diameter end towards subject), 65mm objective separation best. Image quality dropped using minimal and 75mm of separation.
Schneider Componon-S 5.6/180: normal mount + minimal separation tested best.
Schneider Componon-S 5.6/150: normal mount + minimal separation tested best.
Schneider Componon-S 5.6/135: normal mount + minimal separation tested best.
MP5X
Raynox DCR-150 +4.8: normal (lens label towards objective) best, minimum objective separation best
QVHR
Raynox DCR-150 +4.8: normal (lens label towards objective) best, minimum objective separation best
Tube Lenses Tested That Were Not Included
Century Schneider +7: left out for poor results with the HR5X
Raynox +5.9 170mm: left out for poor results with the HR5X
Schneider Makro-Symmar HM 5.6/180: left out for poor results HR5X, this was a major disappointment!
M Plan Apo HR vs M Plan Apo
On the used market you can see objectives with the identification lettering worn off or mislabeled. In that case it is important to know the differences between standard and other models. The easiest way to tell the difference between HR and standard M Plans is the double red lines on the HR versions, also the HR is 8mm longer and has a metal front cover, where the normal M Plan has a black protective bumper ring at the front.
Buying Mitutoyo
Objectives damage easily, one drop can cause a drop in performance so it’s good idea to buy a Mitutoyo from a US store with return privileges, just watch for re-stock fees. If you try Ebay make sure that you only buy from a seller that offers returns with good feedback. When paying use a credit card like American Express so you can run a charge back in case of any issue, don’t use Paypal. Earlier this year I received a damaged lens from China that was not what was promised, the buyer refused to accept the lens back saying I missed the 3 day return period. After I opened a case with Paypal for the not-as-described claim, it took 2 months after the Chinese seller received the lens for Paypal to judge in my favor and issue the $1500 refund.
MICROSCOPE OBJECTIVE SPECIFICATIONS
Identification of the properties of an objectives is easy because most parameters are inscribed or printed on the outer housing (or barrel) of the objective.
View fullsize
Links for more information
Mitutoyo M Plan APO 5X 0.14 tested here on Closeuphotography.com: https://www.closeuphotography.com/mitutoyo-5x-m-plan-apo-objective
Edmunds Optics: https://www.edmundoptics.com/microscopy/infinity-corrected-objectives/Mitutoyo-Infinity-Corrected-Long-Working-Distance-Objectives/
Mitutoyo Objective catalog: http://www.mitutoyo.co.jp/eng/support/service/catalog/04/E14020.pdf
Mitutoyo microscope catalog: http://www.mitutoyo.com/wp-content/uploads/2016/09/I-section-Microscopes.pdf
About Mitutoyo Corporation
In 1984 Japanese precision measuring instrument manufacturer Mitutoyo launched the FS ( Fine Scope) industrial microscope using a new larger and longer M Plan APO objective using a 95mm parfocal length, this is close to twice the length of some of the competition, something other manufacturers could not attempt due to space constraints in their scope systems. The standard M Plan Apo and the bright/dark field BD Plan Apo series were designed with an ultra-long working distance to make good use of the 95mm parfocal distance. The M Plans and BD Plans Plan-Apochromats and this level of correction is typically very expensive, due to the extra-low dispersion glass used in their designs, but thanks to the high volume production, Mitutoyo was able to keep the cost down. These objectives are widely used in manufacturing and research in Asia and this means good availability on the used market, which keeps the prices reasonable.
The M Plan APO HR objectives are made in the Mitutoyo 株式会社ミツトヨ Corporation’s Kawasaki plant. This is the companies headquarters and main factory, located an industrial city of Kanagawa in the greater Tokyo area on the south side of the city. The Kawaski plant opened in 1940 and includes R&D facilities as well as manufacturing. Mitutoyo employs around 5,000 people, selling about 6,000 products and has annual sales around 94,000,000,000 JPY or 800M in USD in 2020. Mitutoyo’s main product focus is metrological technology.
FS (FineScope) Objective Lens Microscope Series development (From Mitutoyo.co.jp)
FS Development Background and Goals
Advances in semiconductor integration have been made with almost dizzying speed in recent years, and with this trend has come new demands to take inspection operations from the micron level to the sub-micron level. At the same time, industries are seeking to develop new high-performance objective lenses in objective lens microscopes, with features such as improved operability, higher resolution, and a long working distance. To meet the challenge of providing both a large numerical aperture and a long working distance, MITUTOYO has reconsidered the 45-mm parfocal distance standard for objective lens microscopes, and has widened the scope of lens design to include parfocal distances up to 95 mm. As a result, MITUTOYO has developed new high-performance objective lens microscopes that feature higher magnification, a larger numerical aperture rating (for higher resolution), and a longer working distance.
Features of FS (FineScope) Objective Lens Microscope
The optical system in FS microscopes is an infinity-correction optical system that uses both an objective lens and an imaging lens (tube lens) to generate images. Aberration correction is performed independently on the objective lens and imaging lens. This optical system is the main feature of the FS Objective Lens Microscope Series of products. Consequently, these products can be used not only as they are, but as part of an expandable system in which users are able to set the imaging lens as they please to incorporate the microscope into their own equipment. MITUTOYO offers several types of imaging lenses, as well as the VMU Series of microscope units equipped with this optical system, the FS70 Series and VM-ZOOM Series of high-powered microscope units, the FS110T inspection microscope, and the MF Series of high-magnification measuring microscopes.
These systems make use of an ultra-long working distance objective lens, which makes possible features not available in previous microscopes and, as such, are unique microscope systems with distinctive operability features.
Generally, when the design for an objective lens calls for a longer working distance, various types of aberrations tend to occur. This poses a problem for optical design, since chromatic aberration is especially likely to occur. In the M Plan Apo Series, apochromat with corrected color aberration in a wide part of the visible range has been achieved by selectively using anomalous dispersion glass and ultra-low dispersion glass with a low refractive index. The wavelength-based refractive index in these types of glass differs from that of ordinary optical glass. In particular, M Plan Apo Series products are able to provide a sharper image, thanks to this correction of lateral chromatic aberration and astigmatism.
FS Objective Lens Microscope Specifications:
M Plan Apo Series / BD Plan Apo Series
The M Plan Apo Series are objective lens microscopes to be used with the visible light spectrum for bright field observations while the BD Plan Apo Series of microscopes are for dark field observations. In addition, there are the "M Plan Apo SL" Series and the "BD Plan Apo SL" Series of models that are designed for long working distances.
M Plan NIR Series / LCD Plan NIR Series
Products in this objective lens series are able to correct chromatic aberration throughout the visible light spectrum and the near infrared region, as they feature an ultra-long working distance objective lens with enhanced functions that boost higher transmissivity in the near infrared region. The LCD Plan NIR Series also features a glass cover (thickness t = 1.1 mm or t = 0.7 mm) specially designed for the LCD.
M Plan NUV Series / LCD Plan NUV Series
Products in the M Plan NUV Series use optical glass that improved the quality of transmissivity in the short wavelength region, and they are able to correct chromatic aberration throughout the visible light spectrum and the near ultraviolet region. An anti-reflective coating has also been developed for these products, to help maintain high transmissivity up to the short wavelength region. Like NIR Series products, these products uses an objective lens (t = 0.7 mm) that is specially designed for LCDs.
M Plan UV Series
Products in this objective lens series feature the latest design in the FS objective lens microscope series, and since last year have been offered in a series of 80X, 50X, and 20X models. To maintain transmissivity even in the ultraviolet region, MITUTOYO has replaced ordinary optical glass with fluorite and synthetic quartz as lens materials. An anti-reflective coating has also been developed for these products.
G Plan Apo Series
When using an objective lens to observe the surface of a workpiece, if a thick glass cover is placed over the workpiece, image's contrast may be reduced sharply by the large amount of spherical aberration produced by the glass cover. This effect is especially great when using high magnification or an objective lens that has a high NA rating. The G Plan Apo Series is an objective lens series developed specifically for observations made through a thick glass cover. Since having an objective lens with a long working distance is an absolute requirement when observing workpieces through a glass cover, this series is the one that makes the most of FS objective lens features. Three types of products are offered: a type for glass covers from 2 mm to 5 mm thick (t = 3.5 mm, BK-7 is standard), a type for fixed glass thickness, and a continuous aberration correction type for thickness of 2 mm to 5 mm (uses an adjustable internal lens).
Typical Uses of Ultra-long Working Distance Objective Lens:
Semiconductor Defect Analyzer (Prober Station)
When a prober station (a type of semiconductor defect analyzer) is used to perform micro-manipulation, a probe (electrode) must be inserted into a semiconductor's aluminum wires under a microscope to perform a conductivity test.
This type of operation can be very difficult if the objective lens' working distance is too short. Consequently, this is one application field where an Ultra-long working distance objective lens is required. For the prober station shown here, MITUTOYO's "FS 70 Series" and "VM-ZOOM" microscope unit can be combined with an ultra-long working distance objective lens series product to achieve maximum performance. Almost all models in the FS Objective Lens Series, including the M Plan Apo,M Plan NIR,M Plan NUV,and M Plan UV models, have features that can be put to effective use in this way.
Laser Processing
The most common method for laser microprocessing that uses a microscope is the mask projection method, for which a YAG laser with a mounted microscope is typically used. The first such lasers used only the YAG fundamental wave (1064 nm), but since then second harmonic wave (532 nm), third harmonic wave (355 nm), and fourth harmonic wave (266 nm) versions have been developed, and other versions are likely in the future. In addition, excimer lasers are coming into use as an alternative to YAG lasers. MITUTOYO objective lenses used with these products include the NIR Series, NUV Series, and UV Series. Users can select the laser best suited for the type of process (from thermal processing in the near infrared region to optical processing in the ultraviolet region) and the materials to be used. Since these objective lenses have a long working distance, there is rarely any problem with the lens becoming contaminated by substances evaporated during laser processing. This makes it comparatively easy to handle workpieces that are in a vacuum chamber or gas environment inside the thick glass cover. The ultra-long working distance objective lens is also used to repair semiconductor masks and LCDs. When it is attached to a prober station (as described above) with a MITUTOYO microscope unit attached to the laser port of the "FS 70" or "VM-ZOOM" as a microscope-equipped laser, the laser can be used to peel off a semiconductor's passivation layer to enable probing.
CNC Vision Measuring Machines
Today, measuring instrument manufacturers are announcing and marketing various CNC vision measuring machines equipped with microscope systems and covering with a wide range of specifications. These products offer many popular features that can help reduce inspection labor costs while raising throughput, that enable even inexperienced users to obtain accurate measurements, and that can improve the working environment by eliminating difficult tasks.
MITUTOYO has developed an assortment of products in the "Quick Vision Series" and "Quick Scope Series" that support a wide variety of workpieces. These are also products that use ultra-long working distance objective lenses. In the field of vision measuring machines, there is a big demand for objective lenses with long working distance, and especially for MITUTOYO products that support workpieces with large level gaps. Many users have responded enthusiastically to the versatility of these products across a wide scope of measurement applications.
Observations through Parallel Panes of Glass
MITUTOYO offers the "G Plan Apo Series" as a product series that meets the specifications for this task. However, given the nearly infinite variety of specifications required by users, these products cover a broad wavelength spectrum from infrared to ultraviolet and use a variety of parallel pane materials including not only optical glass but also synthetic quartz, sapphire glass, diamond, and even liquids. Pane thickness ranges from approximately 0.5 mm to over 20 mm, and some users have requested high NA types as well. Applications also vary greatly, from making observations to laser processing, and in many cases these products are used as a condenser lens. As noted above, these user needs are served by the FS Objective Lens Microscope Series products in general. Some of the things that can be done with an ultra-long working distance objective lens microscope but cannot be done with ordinary objective lens microscopes: observations of workpieces in high-temperature or low-temperature chambers, vacuum chambers, gas-filled chambers, and suspended in liquids. Of course, aberration correction to meet specifications is available in custom-order versions these products, and repeat functions are used to provide suitable optical systems at a reasonable price. One feature of ultra-long working distance objective lenses is the availability of custom order lenses such as these.
Other Uses
There are many other types of MITUTOYO optical equipment and optical measuring machines that also take advantage of ultra-long working distance objective lens features. Some typical examples are described below.
Electron microscope: For semiconductor defect analysis and detection of faint light emitted by leaks, etc.
Micro Fizeau interferometer: Fizeau interferometer that uses an objective lens microscope
Linnik interferometer: Michaelson interferometer uses a pair of objective lens microscopes to provide an optical system for reference optics as well as an optical system for workpieces, and each lens has the same waveform curvature aberration
Laser repair device: This device is used to laser processing repair defects in semiconductor and masks
Microspectroscope: This device microscope uses a microscope to measure reflective optical characters in small areas