Discover the immersive world of AR/MR/VR technologies and their real-world applications in industries like automotive and medicine.
Discover the immersive world of AR/MR/VR technologies and their real-world applications in industries like automotive and medicine.
Learn how Optical Coherence Tomography (OCT) revolutionizes medical imaging. Benefit from precise, real-time, non-invasive tissue imaging.
An optical drawing is a detailed plan that allows us to manufacture optical components according to a design and given specifications. When optical designers and engineers come up with a design, they condense it in an optical drawing that can be understood by manufacturers anywhere. ISO 10110 is the most popular standard for optical drawing. It describes all optical parts in terms of tolerance and geometric dimension. The image below shows the standard format of an optical drawing. Notice thee main fields. The upper third, shown here in blue, is called the drawing field. Under this the green area is known as the table field, and below this the title field or, alternately, the title block (shown here in yellow). Once an optical drawing is completed, it will look something like this: Notice the three fields— the drawing field, the table field, and the title field. We’ll look at each of them in turn. Field I — Drawing Field The drawing field contains a sketch or schematic of the optical component or assembly. In the drawing here, we see key information on surface texture, lens thickness, and lens diameter. P3 means level 3 polished, and describes the surface texture. Surface texture tells us how close to a perfectly flat ideal plane our surface is, and how extensive are the deviations. 63 refers to the lens diameter, the physical measurement of the diameter of the front-most part of the lens 12 refers to the lens thickness, the distance along the optical axis between the two surfaces of the lens After reviewing the drawing field we know this is a polished bi-convex lens, and we know exactly how large and how thick it is. But there is more we need to know before we begin production. To find this additional information, we look at the table field. Field 2— Table Field In our example, the optical component has two optical surfaces, and table field is broken into three subfields. The left subfield refers to the specifications of the left surface, and the right subfield refers to the specifications of the right surface. The middle field refers to the specifications of the material. Surface Specifications: Sometimes designers will indicate “CC” or “CX” after radius of curvature, CC means concave, CX means convex. Material Specifications: 1/ : Bubbles and Inclusions Usually written as 1/AxB where A is the number of allowed bubbles or inclusions in lens B is the length of side of a square in units of mm 2/ : Homogeneity and Striae Usually written as 2/A;B where A is the class number for homogeneity B is the class for striae Field 3: Title Field The last field on an optical drawing is called the title field, and it is here that all the bookkeeping happens. The author of the drawing, the date it was drawn, and the project title will be listed here, along with applicable standards. Often there will also be room for an approval, for a revision count, and for the project company. A final crucial piece of information is the scale: is the drawing done in 1:1, or some other scale? Now you know how to read an optical drawing and where to find the information you’re looking for. If you have any other questions, feel free to contact us!
An IR lens is an optical lens designed to collimate, focus, or collect infrared light. At Avantier Inc., we produce high performance IR Optics such as IR lenses for use with near-infrared (NIR), short-wave infrared (SWIR), mid-wave infrared (MIR), and long-wave infrared (LWIR) spectra. These Infrared lenses can be customized for specific areas of the infrared spectrum, and are suitable for applications in defense, life science, medical, research, security, surveillance and other industries. Why Choose Avantier for Your Infrared Optics Needs Whether you require one-off production of single infrared (IR) lens assembly for a specialized research project or a large quantity of fixed-focus IR lenses for industry use, you need to know you can count on your provider. When you work with Avantier, you know you are getting the best product possible, at the best possible price. Our engineers design for manufacturability and work hard to ensure you get an optimized product at an optimal price and within an optimal time frame. That’s because we’ve done it, again and again. Our extensive experience in infrared optics enables us to both design and produce the highest quality lenses and assemblies for IR light. State of the art metrology and a robust quality control program means that every lens with the Avantier name on it will perform exactly as intended, and we check and double check that each component meets your full specification. Our manufacturing processes meet all applicable ISO and MIL standards, and our IR lenses are well known throughout the world. Types of Infrared Lenses Infrared light is classified as light between the wavelengths of 1 mm to about 700 nm. Infrared IR radiation can be further divided into several categories: The substrate chosen for a lens will depend partly on which IR region it is designed for. For instance, Calcium Fluoride (CaF2) lenses are a good choice for radiation between 80 nm – 8 μm and so would be ideal for NIR SWIR wavelengths. Zinc Selenide has optimal transmission from 8 – 12μm, although it offers partial transmission over 0.45 μm to 21.5 μm and Zinc Sulfide (good transmission in 8-12µm, or partial transmission from 0.35 to 14µm). Avantier and IR Lens Design Our experienced engineers and consultants can help you determine the best substrate and antireflective or reflective coating best fits your application. Every situation is unique, and we can help you find a cost effective solution that meets your need. Whether you need special resistance to mechanical and thermal shock, or good performance in rugged environments, we can select the perfect substrate for you. We can also help design your IR lens or optical lens assembly. From basic lens selection (singlet, aspherical lens, spheric lens, cylindrical lens, custom shape lens) to design of aspheric lenses arranged in a complex opto-mechanical device, or any other infrared optical assembly, we have you covered. Avantier can provide lenses in chalcogenide material. Chalcogenide is an amorphous glass and is easier to process than traditional IR crystalline materials. Chalcogenide glass is an ideal material for both high performance infrared imaging systems and high volume commercial applications. Chalcogenide glass is available in a variety of chemical composition options, but BD6, composed of arsenic and selenium (As 40 Se 60), is the best choice in terms of cost and ease of production. Chalcogenide infrared glass materials and lenses are also an excellent alternative to expensive, commodity price-driven materials such as Ge, ZnSe, and ZnS2. Chalcogenide glass primarily transmits in the MWIR and LWIR wavelength bands, making it suitable for infrared imaging applications. Please contact us if you’d like to schedule a free consultation or request for a quote on your next project.
Identifying Resolution of Imaging Systems Resolution is a measurement of an imaging system’s ability to resolve the object which is be imaged. Test targets are typically tools that are used to check the resolution of an imaging system. The most popular targets consist of “groups” of 6 “elements” and each element consists of three horizontal and three vertical bars equally spaced with well-defined width. The vertical bars are used to calculate horizontal resolution and horizontal bars are used to calculate vertical resolution. Analyzing test target image is to identify the Group Element number of highest spatial frequency where either horizontal or vertical lines are distinguishable. Here is an example of such test target image: To look at the pixel values we have chosen one row which is close to the center of the image. We see that the maximum pixel brightness is 120 counts at the center and about 95 counts at the edge for the test target image. Maximum theoretical pixel value for an 8-bit format image is 255 counts, thus only half of the sensor dynamic range is used for this test. Groups are labeled by numbers in order of increasing frequency. It is obvious that Groups with highest resolution are near the image center. The image part, where the groups 8 and 9 are located, is shown here: To avoid repetitions, we only show the calculation results for the resolution along the horizontal / X direction. To reduce the noise in calculation of the image contrast, each group image of the 3 vertical bars was averaged along Y direction inside the extent of the black bars. The resulting averaged amplitudes along X direction for all the elements of the group 8 are shown here: The signal amplitude difference between black stripe/line and white space is recognizable for the 6 elements of Group 8, i.e., all the 6 elements are distinguishable Next picture shows the same kind of plot for all the elements of the group 9: The signal amplitude difference between black bar/line and white space is countable for the elements 1-5 but is not distinguishable for the element 6 of group 9. The resolution of this imaging system is Group-9 Element-5 with line width of 0.62µm, i.e., frequency of 806 line pairs per mm. It is known that the resolution of an imaging system can be affected by factors such as object/test target contrast, lighting source intensity, and software correction. Increasing the illumination intensity and having proper parameter settings for the camera can improve the resolution of the imaging system.
Today’s advanced driver assistance systems take advantage of AI-spiked cameras and radar or sonar systems, but most manufacturers have been waiting for advances in machine vision technology to go one step further into autonomous self-driving cars. Today, that technology is ready to roll out. We call it LiDAR: Light detection and ranging. LIDAR in autonomous vehicles can create a 3D understanding of the environment of the LiDAR systems, providing a self-driving car with a dynamic, highly accurate map of anything within 400 meters. Understanding LiDAR LiDAR works by sending out laser pulses that reach a target, then bounce back to where a LiDAR sensor measures the time it took for the round trip. This enables the LiDAR system to create a point map that gives the exact location of everything within the reach of the laser beam. While the reach depends on the laser type used, those used in autonomous cars can now provide accurate data on objects up to 400 meters distance. Since LiDAR systems use laser light from a moving source on the car to ‘see’, the technology is not dependent on ambient light and can function just as well at night as during the day. LiDAR is used in more than just self-driving cars. It has become important in land surveying, forestry and farming, and mining applications. LiDAR technology was used to discover the topology of Mars, and is being used today in a program studying the distances between the surfaces of the moon and earth. It can provide soil profiling, forest canopy measurements, and even cloud profiling. LiDAR in Autonomous Vehicles Ten years ago, LiDAR was expensive and clunky, but that didn’t stop autonomous driving pioneers from incorporating it into their prototypes. Google designed a car with a $70,000 LiDAR system sitting right on top of the vehicle, and ran a series of very successful tests in Mountain View, California and around the U.S. There was just one problem: tacking an extra $70,000 bill onto an already expensive car leads to something that is simply not practical for anything besides research. Today, Waymo manufactures self-driving cars using what they learned from those original experiments, and each of these cars is fitted with a similar LiDAR system. The design has been improved over the years, but the most glaring change is a very promising one: advances in technology have enabled Waymo to bring the cost of the LiDAR system down 90%. Now LiDAR technology is available to any manufacturer of LiDAR cars, and our LiDAR optical design specialists can help you come up with a LiDAR system that meets your budget and requirements. Contact us for more information or to chat with one of our engineers.
How Peak to Valley (PV) and Root Mean Square (RMS) Affect the Quality of Your Optics Just how smooth is the surface of your optic? Qualitative descriptions are of limited value, and often you’ll want to put a number to it. Two ways of quantifying deviations from an ideal optical surface are peak-to-valley (PV) and root-mean-square (RMS). While root-mean-square provides more information, peak-to-valley measurements have been used more often historically. Both methods have their pros and cons. Here we’ll look into both in more detail. Understanding Peak to Valley (PV) Measurements A peak to valley measurement represents the distance between the highest point and lowest point on the surface of an optic. Theoretically, this number should be quite useful: for instance, it allows an optical designer to make worse case predictions on optical performance. In practice, though, it is much more problematic. Using peak to valley measurements assumes that all measurements are precise and the surface has no noise. It is most useful if there are large sized features on the optics, or if the order of aberration is low. An actual optic will have numerous imperfections that are closer than a millimeter to the aperture. Measurements from peak to value will be taken with an instrument that is far from ideal; typically, it will have a significant noise level and a large MTF difference. Because of the inherent problems with measurement, optical manufacturers typically have their own measuring method which does little but mask the condition of the optic. Often the measuring instruments are only used to interpolate the standard parameters in a method based more on a study of optical properties rather than the actual optic under consideration. Unfortunately cost and manufacturability are often expected to depend entirely on the value of PV. For instance, we have had customers come in with a minimum budget requesting a 1/10 wave PV optic, with no specifications on testing conditions. This type of demand can only lead to a prohibitively expensive optic, an unworkable project, or the specification reinterpreted by the vendor. Standard manufacturing processes do not admit for 1/10 wave PV. Understanding Root Mean Square (RMS) Measurements A root mean square (RMS) measurement describes the average deviation of the actual optical surface from an ideal surface. While PV gave the ‘worst case scenario’, we can think of RMS as providing the overall surface variation. RMS values are also dependent on measurement, and especially on the relative area of the optic sampled. However, they are typically much more informative than PV values. While some may attempt to convert between PV and RMS measurements by multiplying by 3.5, this is inaccurate and misleading. The two numbers are measuring very different things, and there is a simple relationship between them. A surface may have a large gouge that results in a large PV, but if the rest of the optic is smooth the RMS will reflect that. Similarly, if a surface has a relatively small PV but the surface is completely rough, the RMS will be larger than expected by a look at the PV. Comparing RMS and PV Measurements Below are images which show the plot of 1 micron PV for basic terms of aberration, as well as the corresponding RMS. We see RMS is noticeably different for each basic term of aberrations. When computer-controlled sub-aperture polishing comes into play, we often see cyclic errors. The below plots again show 1-micron PV, but here we have different frequencies of cyclic error. Though you can align pretty much all of the basic aberration in your optical system, cyclic form error will typically not be compensated for. In these images you can see that the PV and RMS measurements end up being essentially the same as basic aberration terms. Now consider the below image, which shows the stimulated plot of an optic where the error consists of many small imperfections and a few larger, localized imperfections. A well fabricated optic will typically be of this kind. In this situation, the PV is still close to the 1 micron we saw in our other plots; RMS, however, is much less. These plots demonstrate how RMS reflects the actual surface quality of the optical system, while PV provides hardly any useful information. RMS is a better specification than PV, but as always, the key is to partner with a trustworthy optics supplier that can work with you to manufacture an optic with the best performance possible at your price point. At Avantier Inc., that’s what we do every day. Contact us for a free consultation, and put our 50+ years of optical experience to work for you.
A microscope is an optical device designed to magnify the image of an object, enabling details indiscernible to the human eye to be differentiated. A microscope may project the image onto the human eye or onto a camera or video device. Historically microscopes were simple devices composed of two elements. Like a magnifying glass today, they produced a larger image of an object placed within the field of view. Today, microscopes are usually complex assemblies that include an array of lenses, filters, polarizers, and beamsplitters. Illumination is arranged to provide enough light for a clear image, and sensors are used to ‘see’ the object. Although today’s microscopes are usually far more powerful than the microscopes used historically, they are used for much the same purpose: viewing objects that would otherwise be indiscernible to the human eye. Here we’ll start with a basic compound microscope and go on to explore the components and function of larger more complex microscopes. We’ll also take an in-depth look at one of the key parts of a microscope, the objective lens. Compound Microscope: A Closer Look While a magnifying glass consists of just one lens element and can magnify any element placed within its focal length, a compound lens, by definition, contains multiple lens elements. A relay lens system is used to convey the image of the object to the eye or, in some cases, to camera and video sensors. A basic compound microscope could consist of just two elements acting in relay, the objective and the eyepiece. The objective relays a real image to the eyepiece, while magnifying that image anywhere from 4-100x. The eyepiece magnifies the real image received typically by another 10x, and conveys a virtual image to the sensor. There are two major specifications for a microscope: the magnification power and the resolution. The magnification tells us how much larger the image is made to appear. The resolution tells us how far away two points must be to be distinguishable. The smaller the resolution, the larger the resolving power of the microscope. The highest resolution you can get with a light microscope is 0.2 microns (0.2 microns), but this depends on the quality of both the objective and eyepiece. Both the objective lens and the eyepiece also contribute to the overall magnification of the system. If an objective lens magnifies the object by 10x and the eyepiece by 2x, the microscope will magnify the object by 20. If the microscope lens magnifies the object by 10x and the eyepiece by 10x, the microscope will magnify the object by 100x. This multiplicative relationship is the key to the power of microscopes, and the prime reason they perform so much better than simply magnifying glasses. In modern microscopes, neither the eyepiece nor the microscope objective is a simple lens. Instead, a combination of carefully chosen optical components work together to create a high quality magnified image. A basic compound microscope can magnify up to about 1000x. If you need higher magnification, you may wish to use an electron microscope, which can magnify up to a million times. Microscope Eyepieces The eyepiece or ocular lens is the part of the microscope closest to your eye when you bend over to look at a specimen. An eyepiece usually consists of two lenses: a field lens and an eye lens. If a larger field of view is required, a more complex eyepiece that increases the field of view can be used instead. Microscope Objective Microscope objective lenses are typically the most complex part of a microscope. Most microscopes will have three or four objectives lenses, mounted on a turntable for ease of use. A scanning objective lens will provide 4x magnification, a low power magnification lens will provide magnification of 10x, and a high power objective offers 40x magnification. For high magnification, you will need to use oil immersion objectives. These can provide up to 50x, 60x, or 100x magnification and increase the resolving power of the microscope, but they cannot be used on live specimens. An microscope objective may be either reflective or refractive. It may also be either finite conjugate or infinite conjugate. Refractive Objectives Refractive objectives are so-called because the elements bend or refract light as it passes through the system. They are well suited to machine vision applications, as they can provide high resolution imaging of very small objects or ultra fine details. Each element within a refractive element is typically coated with an anti-reflective coating. A basic achromatic objective is a refractive objective that consists of just an achromatic lens and a meniscus lens, mounted within appropriate housing. The design is meant to limit the effects of chromatic and spherical aberration as they bring two wavelengths of light to focus in the same plane. Plan Apochromat objectives can be much more complex with up to fifteen elements. They can be quite expensive, as would be expected from their complexity. Reflective Objectives A reflective objective works by reflecting light rather than bending it. Primary and secondary mirror systems both magnify and relay the image of the object being studied. While reflective objectives are not as widely used as refractive objectives, they offer many benefits. They can work deeper in the UV or IR spectral regions, and they are not plagued with the same aberrations as refractive objectives. As a result, they tend to offer better resolving power. Microscope Illumination Most microscopes rely on background illumination such as daylight or a lightbulb rather than a dedicated light source. In brightfield illumination (also known as Koehler illumination), two convex lenses, a collector lens and a condenser lens, are placed so as to saturate the specimen with external light admitted into the microscope from behind. This provides a bright, even, steady light throughout the system. Key Microscope Objective Lens Terminology There are some important specifications and terminology you’ll want to be aware of when designing a microscope or ordering microscope objectives. Here is a list of key terminology. Numerical Aperture Numerical aperture NA denotes