Optical: systems and elements – Compound lens system – Microscope
Patent
1994-11-22
1996-10-15
Nguyen, Thong
Optical: systems and elements
Compound lens system
Microscope
359363, 359385, G02B 2106, G02B 2136
Patent
active
055660207
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to microscopes and more specifically to a high magnification microscopy system with improved high resolution and depth-of-field at 6,000.times. magnification and greater.
BACKGROUND ART
In medical microscopy the objective is to get three things, as good a resolution as possible, as much magnification as you can resolve, and the best depth of field as possible. These objectives in the design of optical systems generally require compromises. In a standard optical microscope the depth of field is inversely proportional to the magnification. As the magnification gets higher the depth of field gets narrower. If the object being viewed is sufficiently small that you have to magnify it to the point your eye can see it, the depth of field gets so narrow that there is no contour to what you are looking at and it blurs since there is no depth of field.
Another aspect in terms of microscopy is the fact that up until a few years ago blood was believed to be sterile. It was thought there was no fungus or bacteria in blood except under severe pathological conditions. Today, systemic micro-organisms in the blood have changed the early thinking that blood was sterile. The discovery of AIDS has resulted in a complete new understanding of the immune system of opportune organisms that take advantage of a depressed immune system. The standard research microscope cannot be used to study organisms because they are too small. In these microscopes the power of magnification is about 1000.times. or 1500.times.. Some sophisticated systems are available where you can get 2000.times., and 2500.times., but the depth of field gets so narrow they are only used for research. What is needed for examination of blood for its organisms is magnification in excess of 5000.times.. Also the depth of field must be sufficient that the total contour of the organisms can be seen. To give a general idea of the problem, if a person wants to see a red blood cell they need a depth of field of at least 7 microns. If the depth of field drops to 31/2 microns, it is only possible to see half the red blood cell. As the depth of field becomes progressively less, a person can only see a slice of the blood cell. If the interest being researched relates to membranes and things of this sort, a different approach has to be taken to break out of the limitations of a standard optical system.
Another important criteria that hadn't been looked at is most research microscopes concentrate on what is known as dark field microscopy. The problem is how do you illuminate and contrast what you want to look at? Also what type of light source could be used to try to enhance the contrast? Some of the new microorganisms need to be studied and are not seen in dark fields. It is therefore necessary to go to other types of optical modes, like phase contrasts, polarized light, as well as dark fields. This gets into things like differential interference phase. These are different ways of enhancing different types of light. As it turns out, it is necessary to do all of the three or four types of optical modes in addition to increasing magnification and depth of field. Due to the physics of optics, you can only get so much magnification if you want to maintain some sort of depth-of-field. It was determined that optimal magnification must be around 400.times. instead of 1000.times.. Therefore in order to gain the degree of required magnification necessary for visible analysis, it was determined that projection magnification could be used in conjunction with the initial optical magnification. A unique microscopy system has been designed by the applicants to combine a projection lens with the research microscope after it has received its optical magnification. The extra magnification produced by the projection lens does not affect the depth of field as the beam spreads out. The projected image may be received by a video camera and it is moved either toward or away from the projection lens in order to vary the amount of magnification. The resolutio
REFERENCES:
patent: 4331132 (1981-05-01), Mukasa
patent: 4643540 (1987-02-01), Kawasaki et al.
patent: 4725720 (1988-02-01), Sawada et al.
patent: 4887892 (1989-12-01), Bacus
patent: 4911543 (1990-03-01), Hodgson
patent: 5006872 (1991-04-01), Parker
patent: 5497267 (1996-03-01), Iskikawa et al.
Bradford Robert W.
Yent Gregory D.
Logan II Charles C.
Nguyen Thong
LandOfFree
Microscopy system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Microscopy system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microscopy system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1251419