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Magnifying glass - is it necessary in principle in everyday life, is it worth spending time on making it? There are a wide variety of lenses available for sale. But sometimes you want to make something with your own hands. Sometimes it happens. You've probably read “The Mysterious Island” by Jules Verne. I never wanted to repeat the experience of Cyrus Smith, who made a wonderful magnifying glass from a watch. In essence, this simple device saved the lives of the colonists. Intrigued? Then now we will tell you how to make a magnifying glass at home. Let's consider several ways.
Why should you try making a telescope?
We can definitely say that astronomy is a very complex science. And it requires a lot of effort from the person doing it. A situation may occur that you purchase an expensive telescope, and the science of the Universe will disappoint you, or you simply realize that this is not your thing at all.
In order to figure out what’s what, it’s enough to make a telescope for an amateur. Observing the sky through such a device will allow you to see many times more than through binoculars, and you will also be able to figure out whether this activity is interesting to you. If you are passionate about studying the night sky, then, of course, you cannot do without a professional apparatus.
Liquids unsuitable for storage
- Ordinary water is not suitable for liquids where to put lenses if there is no solution , since it already contains a large number of bacteria, which, in turn, can lead to the formation of mold. This also includes boiled and distilled water.
- It is strictly forbidden to wipe the surface of the lens with saliva, for the same reason as with water.
- If you completely refuse to use liquid, this will lead to drying out of the surface and damage not only to the material, but also to vision..
Attention! It is recommended to use substitutes only in extreme cases, for example, if there is no liquid for lenses, and it is not yet possible to buy a new one.
What is a fresnel lens
A Fresnel lens is a complex compound lens. Unlike ordinary lenses, it does not consist of a single ground piece of glass with a spherical surface, but of individual concentric rings. They are tightly adjacent to each other and have a small thickness. In cross-section they are prisms of a special profile.
Thanks to its unique design, this lens model is lightweight and thin. The sections of its rings are constructed in such a way that its spherical aberration is extremely small, as a result of which the rays refracted by it emerge as a single parallel beam. The diameter of the Fresnel lens varies from a couple of centimeters to several meters.
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Fresnel lenses are usually divided into ring and belt. The first direct a beam of light in one predetermined direction. The latter send light from the source in all directions in one plane.
Let's get to know the world around us
Children aged 3 to 6 years are desperate whys. It’s a good idea if they learn the causes of various physical phenomena from an early age. Of course, what you will do now can be called a magnifying glass with great stretch, but the experiment turns out to be quite beautiful.
You will need:
- Three liter jar.
- Thick thread.
- Transparent colorless polyethylene film.
Operating procedure:
- Place an object in the jar. Cover the neck of the jar with film so that it sags a little. This is understandable: the lens should be convex.
- Secure the polyethylene with thick thread, tape or twine.
- Now pour water onto the surface of the film. Water plays the role of a magnifying lens. The object inside the jar appears larger.
How to determine the magnification of binoculars?
We can easily find out the focal lengths of the resulting lenses by placing a sheet of white paper under them and shining light on this sheet through the lens. The distance to the lens at which the light beam is focused into a point is the focal length of the lens.
Now we can easily calculate the degree of magnification of our future binoculars. To do this, the focal length of the large lens is divided by the focal length of the small lens. The result obtained will indicate the magnification factor of your binoculars.
What materials are the lenses made of?
Contact lenses have made life more comfortable for millions of people with poor vision.
They are convenient and safe. The first devices did not have these qualities.
Imagine what sensations a person might have if he placed a fragile glass product in the shape of a hemisphere in his eye, and this is exactly what lenses were like about a hundred years ago.
Fortunately for bespectacled people, with the development of polymer chemistry, new materials appeared and production technologies improved - wearing contact optics has ceased to be an extreme activity for pain-seekers.
Manufacturing materials
The cornea of the eye receives nutrition and oxygen from the surrounding air and tear fluid. Tears also cleanse the cornea, washing away impurities. If, due to the lens being worn, air access is stopped or the tear film is disrupted, the cornea immediately signals us about this with pain. Today, CL manufacturers have achieved that optics made from modern materials, when in front of the eyes, almost do not make themselves felt.
The first CLs, as mentioned above, were made of glass using grinding.
In the 40s of the 20th century they switched to organic glass lenses. They were convex, large, covered the entire area of the sclera, the cornea and did not allow oxygen to pass through. Finally, in the 60s, thin, small lenses made of hydrogel appeared. Placed on the cornea, they were held there by capillary attraction.
Essentially, these were already modern soft contact lenses.
Materials that are currently used in the manufacture of CL: hard and soft polymers (hydrogel, silicone hydrogel, water-gradient). To choose the right contact correction means, you need to have an idea of the characteristics of the materials from which they are made.
Rigid polymers
They are used to make hard contact lenses. These materials are characterized by a high molecular density: water and oxygen do not penetrate this structure. The cornea receives oxygen contained in the tear film. Today, LCLs are gas-permeable; this is achieved by adding silicone to the matrix, the structure of which does not delay the flow of oxygen.
The service life of hard lenses is much longer than that of soft ones, but it is more difficult to adapt to them.
GCL (gas-permeable GCL) keep their shape well, they are worn by people with a high degree of astigmatism and keratoconus. They are used to correct corneal defects after injuries and operations. ZhGKL are used as night ortho-lenses: they are worn while sleeping, that is, by rebuilding the corneal epithelium, astigmatism and myopia are temporarily corrected.
Soft polymers
Used to make soft contact lenses worn to correct various refractive errors. The hydrogel is responsible for the moisture content, and the silicone is responsible for the ability of the product to transmit oxygen. They are comfortable and do not require long adaptation.
Hydrogel
Hydrogel lenses are soft and elastic, they contain a lot of water and they wet the cornea well, which helps avoid dry eyes. However, oxygen supply is provided mainly by tear fluid.
Hydrogel SCLs are suitable exclusively for daytime wear, but are inexpensive and are popular as routine replacement corrective lenses.
Silicone hydrogel
These polymers have a lower moisture content compared to hydrogel. But due to silicone, their oxygen permeability is 4-6 times higher. This allows the eyes to “breathe.” To increase hydrophilicity, the surface of the product is subjected to plasma treatment or wetting agents are added.
SCL made of silicone hydrogel can be worn for a long time, even without removing it while sleeping, without the risk of corneal hypoxia. However, the addition of silicone makes the lenses more rigid and may cause fatigue and dry eyes when wearing them.
Water-gradient
Water-gradient lenses have recently begun to be produced from silicone hydrogel. Their peculiarity is in their structure, which allows them to combine excellent oxygen permeability and at the same time excellent water retention. The core of the product contains silicone hydrogel with a low moisture content, which gradually increases towards the surface and reaches 80%.
On the outer surface there is a hydrogel with a moisture content approaching 100%. Such lenses are even called “contactless”.
Preparation method
There are several methods used in the production of contact lenses.
Turning
Used for the manufacture of hard gas-permeable and soft CLs. Dry polymer blanks are taken and processed on a special lathe. This method is used to make lenses of the most complex shapes, even with several radii of curvature.
Casting
Liquid polymer is poured into metal matrices, like dough into baking molds.
How to make binoculars? homemade binoculars with your own hands
Optics/NVD
Homemade binoculars, of course, will not be able to compete with industrial designs. But if you want to please your child or surprise your friends, then binoculars made using the proposed method will give you this opportunity. In addition, it can even be used for its intended purpose. And the quality of the binoculars you make will depend only on your accuracy and patience.
Our binoculars will consist of two absolutely identical parts, connected to each other along the width of a person’s eyes. Each part of the binoculars consists of two cylindrical tubes of different diameters and lengths. Each tube contains a pair of lenses.
The principle of operation of the binoculars we create is very simple: rays of light coming from a distant point are refracted at the front lens, called the objective, and enter the rear lens, called the eyepiece. And already from the eyepiece they fall on the retina of our eye. Our task will be to manufacture the necessary lenses and install them in the body we make.
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How to replace lens solution?
Even if you don’t have a special solution for cleaning products at hand, there are substitutes that will do an excellent job of this role.
It is important that alternative methods are safe for the patient, do not cause a feeling of “mote in the eye” and are comfortable to use around the clock.
The most popular options for replacing lens solution:
- Saline solution is the most suitable substitute for lens fluid. This solution for lenses, at home, can replace a special liquid for some time. The container in which the products are placed must be disinfected; you can even boil it first and only then pour in the saline solution. You can store lenses in this product, periodically replacing it with a new one. The container can only be closed when the products are completely under saline solution.
- Some eye drops (such as Visine: Clear Tear) are also used as lens fluid , as they prevent the surface from drying out. The composition includes special components that allow the solution to be disinfected and do not pose a threat to humans.
How to make a magnifying glass at home?
With the release of iOS 10, Apple has introduced a number of great new features to its mobile operating system. However, during their presentations, the Cupertino team pays attention only to key changes, ignoring less noticeable, but no less useful functions. You just need to point the camera at the desired object and adjust the desired magnification on the device screen.
To Apple's credit, the app actually works very well, providing the user with a clear picture on the latest iPhones. The user can not only adjust the brightness and contrast, but also use effects. In order to switch the camera to magnifying glass mode, you need to quickly press the Home button three times.
We have so many things in digital form that can save space and are better used in digital form rather than in.
Features of choosing liquid for contact lenses
Important! Ophthalmologists recommend paying attention not only to the composition of solutions, but also to their quality. Thus, when purchasing cheaper products, they cannot always meet the client’s expectations.
You can satisfy the buyer’s wishes by knowing some of the nuances of choice:
- The composition plays a big role when choosing liquid for contact lenses, but, as a rule, the most popular brands are chosen, such as Renu . Manufacturers create specific formulas for each type of solution, which, in turn, have a bactericidal and disinfectant effect. One of the main components will remain the chelating element and the buffer substance.
- You need to choose a solution for its intended purpose for every day or a universal one, which is more convenient. In terms of caring for daily products, you do not need much time, since they must be changed constantly.
- But multifunctional options must be placed in a special solution before going to bed, which will get rid of bacteria, germs, protein deposits, and dust .
- The label and description of the composition of the liquid should be studied in advance before purchasing, since, for example, peroxide products have very serious contraindications.
Attention! It is important to undergo a preliminary examination and, based on this, determine whether there are any allergic reactions. Only a specialist will be able to select a drug based on individual characteristics. It's quite difficult to do this yourself.
Telescope assembly
The lens for the lens is fixed in a small tube with its convex outward. It is recommended to fasten it using a frame, which is a ring similar in diameter to the lens itself. Directly behind the lens, further along the pipe, it is necessary to equip a diaphragm in the form of a disk with a thirty-millimeter hole exactly in the middle.
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Naturally, the eyepiece assembly cannot do without the eyepiece itself. First you need to prepare fastenings for it. They are made in the form of a cardboard cylinder and are similar in diameter to an eyepiece. The fastening is installed inside the pipe using two disks. They are the same diameter as the cylinder and have holes in the middle.
How to properly store lenses?
It is especially important to know how to store products for those who use reusable options and, of course, what you can replace the contact lens solution with if you don’t have the original one on hand.
If the client will use the same pair of products for a long time, he should familiarize himself with the rules for storing liquids for them.
If the packaging of the vision correction device has not yet been unsealed, the shelf life may last as long as indicated in the corresponding column.
How to use and store products, and what to do if there is no solution for lenses:
- Purchasing a special container is a prerequisite for storing this kind of material.
- The liquid is used only once to clean the surface of the lenses; it is not recommended to do this again.
- It is better to regularly inspect the container with a magnifying glass for contamination.
- It is not recommended to mix the remains of the old solution and the new one; each time you should thoroughly rinse the container. If you have completely run out of the branded solution, you can make lens liquid at home (more on that below).
- Heat treatment of the container itself once a week is also necessary.
- The cleanliness of products that are removed from the solution is ensured by washing your hands well and using tweezers as a holder.
- Products should be completely immersed in the solution ; some manufacturers even have special marks for correct pouring of liquid.
To keep your vision at the desired level and prevent it from falling, you should follow these simple rules.
Magnifying glass
VIDEO ON THE TOPIC: Fresnel lens A magnifying glass is a unique thing that allows you to look at the world in a new way. The main function of the device is to magnify small objects. There is an opinion that the device is used by people with impaired vision. But this is far from true!
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Watching videos and images on a home projector is a very exciting and interesting experience. After all, you will always have the opportunity to invite friends and watch a feature film together on a wide screen. Moreover, with the development of technology, new digital projectors began to appear in stores. However, their prices are not affordable for everyone. But is there a way out of this situation? It turns out there is.
The method of making a magnifying glass is described in Jules Verne's novel Captain Nemo. You need to take two convex glasses from a watch, glue them together in natural conditions using wood resin, fill the empty space between these glasses with water and the magnifying glass is ready. As a magnifying glass, such glass will not be entirely perfect, but it will be quite useful for collecting the sun's rays at a point and starting a fire.
From a plastic bottle
You will need:
- A bottle made of transparent (not colored!) plastic with a semicircular top, without relief.
- Scissors.
- Two-component epoxy glue or “Superglue”.
- A roll of electrical tape. This will serve as a template for the magnifying glass.
- Marker.
- 20 ml syringe with needle.
The procedure is as follows:
- Cut off the top of the bottle with scissors. This is exactly what you will need in your work.
- Using an electrical tape template, cut out two identical convex circles. These are the two halves of the future lens.
- Connect two circles and glue the joint with epoxy glue or “Superglue”.
- Place the workpiece in water. This is necessary in order to check the tightness of the structure. Small bubbles will appear in the unsealed areas. Mark these areas with a marker and then seal them.
- Make a hole with a syringe needle.
- Fill the space between the two plastic shells with salted water.
Important! You can use regular tap water with a little bleach added. This is necessary so that the water does not deteriorate and turn green over time.
Magnifying glass is ready! Tested: it is no less convenient to use than a regular store-bought lens.
