Optical Comparator Microscopes

Advantages of Optical Comparators

opticalcomparatormicroscopes — Mon, 14 May 2007 02:43:32 +0000

Optical comparators have been used for more than 50 years and remain a versatile and cost-effective technology for monitoring the processes and quality of a broad range of manufactured parts. Originating from static overhead projectors that displayed magnified images of screw threads onto a wall for manual measurement, optical comparators have evolved into full-featured machines that use modern mechanical, electrical and optical technology to minimize inspection time and maximize cost savings. Believing after seeing is appropriate when referring to optical comparators. Because these measurement tools display a magnified image of a part, a tremendous amount of information about that part can be gathered in a short time simply by looking at the image. Optical comparators, for those unfamiliar with them, are inspection machines that project magnified images of parts onto a glass screen using illumination sources, lenses and mirrors for the primary purpose of making 2-D measurements. One advantage of optical comparators can provide more information than just simple dimensions. Length and width measurements of the part shown above, for example, can be quickly obtained from two separate measurements by using a micrometer. (more…)

New Advancement in Optical Imaging

opticalcomparatormicroscopes — Mon, 14 May 2007 02:38:01 +0000

To sustain the growth of technology, the use of lenses and optical imaging for manufacturing has been standard on the factory floor for more than 60 years. Early on, manufacturers of close tolerance products depended on a highly skilled technician to acquire non contact magnified images and take simple measurements. Those applications were analog, the computer was the brain of a person, motion was controlled by hand and the image receptor was the eye of the craft man or a film camera. Memory was the notes on the log sheet with a number two pencil. The optical comparator and microscope were the primary tools used to magnify the image of the part feature. The operation of optical instruments almost always follows the applications steps of image, measure, analyze, move and repeat. The sequence has not changed much over time. But, since 1980s, each of these individual steps has been steadily enhanced by the advent of the personal computer. Non contact video measuring systems are one example of a product that has improved these process steps. Video-based products used the PC and computer numerical control mechanics to automate these repetitive functions and improve productivity. Up to date advances in optical imaging, computers and wireless communications are creating a new digital-to-data revolution that affects how products are manufactured. Digital products are everywhere. (more…)

Type 621 Mann Comparator

opticalcomparatormicroscopes — Mon, 14 May 2007 02:27:45 +0000

The comparator was built in order to make very precise measurements on very large photographic plates or rolls of film. In particular, it was used by NRAO for many years for finding coordinates of objects on the Palomar Sky Survey plates for possible optical matches to what the radio astronomers had found in the same regions of the sky. It was also used by astronomers at McCormick Observatory for producing finding charts of areas of the sky that they were interested in studying. An accuracy of 1 micrometer could be reached with the instrument, and plates as large as 14 inches by 17 inches in the X and Y directions could be measured. This measurement was done by moving the photographic plate beneath a microscope along accurately scraped ways. By reading the dial on the X and Y direction screws, one could measure very accurately the relative positions of objects on the plates. David Mann, in 1957, manufactured the Type 621 Mann Comparator. Incorporated and used for 20 years by the Central Intelligence Agency of the United States of America. During this time, in the heat of the Cold War, the first space photographic reconnaissance satellites were launched in order to photograph areas of the Soviet block countries and confirm their developments in strategic missile capabilities. (more…)

Biggest Improvements In Microscope

opticalcomparatormicroscopes — Mon, 14 May 2007 02:21:52 +0000

For hundreds of years, the basic structure of the microscope has remained pretty much the same. However, constant improvement has added functionality. Experts noted the most recent improvements in microscope technology. The biggest improvement in microscopes is the change from fixed tube length to infinity-corrected optics. In the past, microscopes had a fixed optical length of about 160 mm from the objective lens to the eye. This meant that light had to hit the object at just the right angle and distance from the lenses or the user would not get a clear picture. In simplest terms, infinity-corrected lenses enable the light to emerge parallel or focused to infinity, within the microscope. Plus, within this parallel range of light, devices such as beam splitters, polarizer and prisms can easily be added without the user losing optical quality. Another improvement is the quality of lenses. Now, with computers designing the lenses and computers controlling the machines that actually make the lenses, they are better than ever before. (more…)

Measuring Up With a Microscope

opticalcomparatormicroscopes — Mon, 14 May 2007 02:20:36 +0000

People try to substitute the measuring microscope with vision systems, but when you need advanced optical techniques, there is no other tool that you can select. Different an optical comparator or video system, a microscope can offer several ways of looking at an object to highlight specific features. By using specialized lenses or manipulating the projected light, the user sees things otherwise invisible under basic microscopic conditions. The bigger magnification, the more illumination you need. There are some very high-intensity lighting techniques, along with various positions you can put lights in. You can light from behind, from the side at different angles, depending on what features you want to observe. Collecting data from a measuring microscope is similar to the process used with optical comparators. Linear scales are built into the stage and often into the focusing mechanism of the microscope. With a computer attachment, the scales automatically measure and record the distance each time movement occurs. It is the ability to measure that motion that makes the tool not only an important imaging device, just like a compound microscope, but also a measuring device. For additional data collection, an image capture device, such as a video or digital camera, can be mounted onto the microscope. Fifty percent or more of our microscopes are sold with a digital camera for documentation. (more…)

Microscope of the Toolmakers

opticalcomparatormicroscopes — Mon, 14 May 2007 02:19:10 +0000

A typical anatomy of a microscope consists of a tube extending down toward a flat plane called the stage and up toward the eyepiece, through which the user views an object. At the distant end of the tube is a turret of objective lenses. Another lens near the eyepiece further magnifies the image, so that full magnification is determined by multiplying the power of both lenses. For example, if both lenses magnify to the 10th power, the total magnification is 100X. A light source on or around the stage allows the user to see specific features of the object being viewed. This basic structure has been manipulated over time to create specific types of microscopes for particular uses. From the standpoint of all things on Earth and investigations into their minute structure, all microscopes can actually be considered quality control or quality assurance instruments. Regardless of the sample, microscopes reveal micro-structural detail that is used in an extremely wide range of qualitative and quantitative report criteria, from blood samples to metallurgy. One difference between a microscope used in quality control compared to one used for biomedical and scientific purposes is the sample itself. In the quality assurance laboratory, many of the specimens like steel and silicon wafers, semiconductors, tool edges, etc., are not transparent, so viewing them is fairly simple by shinning a light on them. However, in the biomedical research lab, the samples are often transparent, such as living tissue and cells. So the researcher needs to incorporate more elaborate illumination techniques to properly observe the object. (more…)