A freeform aspheric version of the classic Dyson design gives much improved aberration correction and makes for designs that are fast speed and have a large field size, especially large rectangular strip fields
Innovation in optical design - a short historyDave Shafer
A short history of innovation in optical design, with literally "thinking outside the box" - seeing new optical ways to use a particular spatial region, like a box.
Multiple solutions in very simple optical designsDave Shafer
Several optical design examples show how multiple solutions can exist even in very simple systems. Time spent in looking for them is often more useful then simply optimizing the first solution that you find, which may not be the best of the alternates..
Broad band catadioptric design with long working distanceDave Shafer
A broad spectral band high NA catadioptric design is developed that has a long working distance. The design is developed from first principles and the evolution of the design shows what the process of lens design is like.
A survey of some unusual telescope designs. One has a 20 meter diameter f/1.0 spherical primary mirror while others are suitable for amateur astronomers to make.
Modified freeform offner, august 11, 2021Dave Shafer
An Offner 1.0X relay system can be given a greatly increased field size with good aberration correction by adding to the design two 45 degree flat fold mirrors that are given some freeform aspheric deformation.
Innovation in optical design - a short historyDave Shafer
A short history of innovation in optical design, with literally "thinking outside the box" - seeing new optical ways to use a particular spatial region, like a box.
Multiple solutions in very simple optical designsDave Shafer
Several optical design examples show how multiple solutions can exist even in very simple systems. Time spent in looking for them is often more useful then simply optimizing the first solution that you find, which may not be the best of the alternates..
Broad band catadioptric design with long working distanceDave Shafer
A broad spectral band high NA catadioptric design is developed that has a long working distance. The design is developed from first principles and the evolution of the design shows what the process of lens design is like.
A survey of some unusual telescope designs. One has a 20 meter diameter f/1.0 spherical primary mirror while others are suitable for amateur astronomers to make.
Modified freeform offner, august 11, 2021Dave Shafer
An Offner 1.0X relay system can be given a greatly increased field size with good aberration correction by adding to the design two 45 degree flat fold mirrors that are given some freeform aspheric deformation.
Freeform aspheric version of the 1.0 x offner relay, june 08, 2019Dave Shafer
A better version of my other Slideshare posting on this topic, with fancier graphics - due to my co-author Luc Gilles. Notice, in particular, the 5 reflection design at the end of the slides. It would be much more useful than the 3 reflection design, due to a wide separation of object and image.
One example is given of a fast speed wide angle telescope design that uses freeform aspherics to give great performance gains compared to conventional aspherics
New catadioptric design type fast speed and wide fieldDave Shafer
A very simple catadioptric design is described that is capable of providing fast speed, like f/1.0, over a telecentric 65 degree field diameter with excellent aberration correction and an external pupil
A modification of the Double-Gauss design with two diffractive surfaces is described with very enhanced performance. The key is an interaction between the aberrations of the two diffractive surfaces and the aberrations of a curved substrate lens.
Dennis gabor's catadioptric design and some new variationsDave Shafer
A variety of optical designs are developed and discussed, inspired by Gabor's very simple and largely unknown design. Some are extremely high NA (0.999!!!) with a wide field of view and diffraction-limited correction.
A method is described of designing cell phone lenses that automatically results in much smoother surfaces without the usual very "wiggly" aspheric shapes.
Extreme pixels per volume optical designDave Shafer
The surprising benefits are shown of superimposing a diffractive surface on top of an aspheric surface to get very high performance designs with a very narrow spectral bandwidth. The combination on the same surface allows independent control of a ray's direction and phase..
The triplet, an embarrassment of riches, 1988Dave Shafer
A variety of 3 element designs are discussed which are corrected for the 5 Seidel 3rd-order aberrations. These are monochromatic designs and use lens thickness as an important design variable.
A remarkable new telescope objective designDave Shafer
A new apochromatic telescope objective is described, due to Joe Bietry, which is fast speed and has astigmatism correction to give very high performance while minimizing the cost of the expensive anomalous dispersion glasses used.
A high performance design is described that uses freeform aspherics to give an unobscured reflective telescope with a 22 degree field of view at f/2.0 on a flat image with no vignetting. The entrance pupil is out in front of the system, one focal length in front, and that is very difficult to achieve.
Freeform aspheric version of the 1.0 x offner relay, june 08, 2019Dave Shafer
A better version of my other Slideshare posting on this topic, with fancier graphics - due to my co-author Luc Gilles. Notice, in particular, the 5 reflection design at the end of the slides. It would be much more useful than the 3 reflection design, due to a wide separation of object and image.
One example is given of a fast speed wide angle telescope design that uses freeform aspherics to give great performance gains compared to conventional aspherics
New catadioptric design type fast speed and wide fieldDave Shafer
A very simple catadioptric design is described that is capable of providing fast speed, like f/1.0, over a telecentric 65 degree field diameter with excellent aberration correction and an external pupil
A modification of the Double-Gauss design with two diffractive surfaces is described with very enhanced performance. The key is an interaction between the aberrations of the two diffractive surfaces and the aberrations of a curved substrate lens.
Dennis gabor's catadioptric design and some new variationsDave Shafer
A variety of optical designs are developed and discussed, inspired by Gabor's very simple and largely unknown design. Some are extremely high NA (0.999!!!) with a wide field of view and diffraction-limited correction.
A method is described of designing cell phone lenses that automatically results in much smoother surfaces without the usual very "wiggly" aspheric shapes.
Extreme pixels per volume optical designDave Shafer
The surprising benefits are shown of superimposing a diffractive surface on top of an aspheric surface to get very high performance designs with a very narrow spectral bandwidth. The combination on the same surface allows independent control of a ray's direction and phase..
The triplet, an embarrassment of riches, 1988Dave Shafer
A variety of 3 element designs are discussed which are corrected for the 5 Seidel 3rd-order aberrations. These are monochromatic designs and use lens thickness as an important design variable.
A remarkable new telescope objective designDave Shafer
A new apochromatic telescope objective is described, due to Joe Bietry, which is fast speed and has astigmatism correction to give very high performance while minimizing the cost of the expensive anomalous dispersion glasses used.
A high performance design is described that uses freeform aspherics to give an unobscured reflective telescope with a 22 degree field of view at f/2.0 on a flat image with no vignetting. The entrance pupil is out in front of the system, one focal length in front, and that is very difficult to achieve.
A survey of some interesting Gregorian telescope designs includes some with all spherical surfaces as well as some with a 20 meter spherical f/1.0 primary mirror and sub-aperture corrector mirrors.
Lens designs with extreme image quality featuresDave Shafer
A variety of lens designs is described which have some image quality feature which is extreme - like an extremely wide spectral bandwidth or extremely high resolution.
Freeform aspheric telescope with an external pupilDave Shafer
A 4 mirror telescope design with freeform aspherics is described which has a distant external front pupil, for those situations that require this. It is unobscured and has a 10 degree diameter field at f/3.0 on an unvignetted flat image.
Schmidt's three lens corrector for a spherical mirrorDave Shafer
Schmidt's aspheric plate in a Schmidt telescope design can be replaced by a group of three spherical lenses, as Schmidt himself showed, but he died before he could publish anything on this. Here I show many alternate versions to Schmidt's design.
Wide angle fast speed lens with only 4 elementsDave Shafer
A 90 degree field f/2.0 design (with no vignetting) is described that consists of just 4 lenses. All surfaces are aspheric and there is no color correction. The aberration correction is very high over the whole field.
progressive lenses, multifocal lenses, polyfocal lenses, lenses for presbyopia, bifocal lenses, lenses for near reading, lenses for the elderly, above age 40
This presentation is mainly focused on progressive addition lenses along with the brief description of single vision reading lenses ,bifocal and trifocals which are the other options available for the management of presbyopia. It also include a short description on the fitting of the PAL. PAL is the most used option worldwide for the management of presbyopia .PAL is also used in the management of progressive myopia and the studies shows it is more effective than the bifocal lenses. PAL are more effective in myopia management when the myopia comes along with the near esophoria and accommodation lag. In this modern century personalised progressive lenses are the most effective in matching the need of the patients.
By using a diffractive surface to provide most of the focusing power, combined with aspheric lenses, a simple fast speed wide angle design is possible with excellent image quality. But a very large amount of color limits the useful spectral bandwidth to a very small amount.
A 100 mm focal length f/1.25 design is described with a 20 degree field diameter and a curved image. It is diffraction-limited over the field from .486u to .6563u.
A wide angle fast speed unobscured freeform aspheric mirror design for the IR is shown to be enormous in size compared to an all refractive 3 element lens of germanium with conventional aspherics and better performance.
New optical system corrected for all third order aberrations for all conjugat...Dave Shafer
An afocal unit magnification optical system is described which is corrected for 3rd order spherical aberration, coma, astigmatism, Petzval and distortion for all conjugate distances
The biblical Exodus - what really happened?Dave Shafer
An attempt to explain by natural causes most of the events of the biblical Exodus as If they had actually happened. Whether or not they did happen is not relevant to this presentation.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
Water billing management system project report.pdfKamal Acharya
Our project entitled “Water Billing Management System” aims is to generate Water bill with all the charges and penalty. Manual system that is employed is extremely laborious and quite inadequate. It only makes the process more difficult and hard.
The aim of our project is to develop a system that is meant to partially computerize the work performed in the Water Board like generating monthly Water bill, record of consuming unit of water, store record of the customer and previous unpaid record.
We used HTML/PHP as front end and MYSQL as back end for developing our project. HTML is primarily a visual design environment. We can create a android application by designing the form and that make up the user interface. Adding android application code to the form and the objects such as buttons and text boxes on them and adding any required support code in additional modular.
MySQL is free open source database that facilitates the effective management of the databases by connecting them to the software. It is a stable ,reliable and the powerful solution with the advanced features and advantages which are as follows: Data Security.MySQL is free open source database that facilitates the effective management of the databases by connecting them to the software.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
1. Dave Shafer
David Shafer Optical Design
Fairfield, CT 06824
203-259-1431
shaferlens@sbcglobal.net
Freeform Dyson Design
2. Classic Offner 1.0X monocentric design
Freeform Offer design with very
large rectangular strip field
Using freeform aspheric surfaces allows the classic Offner design with
spherical surfaces to have greatly increased field size with good correction
https://www.slideshare.net/operacrazy/freeform-aspheric-version-of-the-10-x-offner-relay-june-08-2019
3. Classic monocentric 1.0X Dyson design Classic monocentric 1.0X Wynne-Dyson design
Different glass types
The classic Dyson design is, like the Offner design, corrected for all the 3rd order aberrations.
The Wynne-Dyson design adds 5th-order correction due to two glasses with different index and
dispersion values. Chromatic variation of astigmatism and Petzval is also corrected. Only
spherical surfaces are used in these designs.
4. In order to avoid vignetting due to the small
convex mirror the Offner design has to be used
pretty far off-axis. That makes it impractical for
fast f# situations and also limits performance
due to higher-order field aberrations
The Dyson design has no vignetting problems
and so can work well at much faster speeds than
the Offner design, due to working closer to the
optical axis. But the long glass path and lack of
any working distance limits the practical size of
the system and its suitability when a sizable
working distance is required
5. By making the mirror surface and the convex
lens surface both be freeform aspherics the
design can be well-corrected over a very large
strip field that goes in and out of the plane of
the page. Or a well-corrected smaller square
field that is much larger in the plane of the
page than the classic Dyson design with similar
image quality.
If the freeform design is given a good working
distance, as shown here, then making the
surface closest to the object/image also a
freeform surface gives even better aberration
correction. But then the design has color that
needs to be corrected.
6. Color can be well
corrected by adding a weak
power lens near the mirror,
of the same glass type as
the main lens.