Is a Aspherical Camera Lens Better than a Spherical Lens?

 Is a Aspherical Camera Lens Better than a Spherical Lens?

 

The Aspherical Camera Lens

When it comes to the lens, you have to mention the aspherical lens. In many people's understanding, the aspherical lens is a symbol of high level, and the advanced lens is almost all aspherical lens.

 

Let's start with what is called a aspherical lens. The aspherical lens is contained in the camera lens, aspheric is often calculated according to the surface, some aspherical lens side, the other is not, or both sides is spherical, and so on.

 

In general, a lens with two or more aspherical lenses is a very advanced lens. So, is the aspheric surface a very difficult technique?

We can look at it from the other side.

 

Now, in terms of glasses, the aspheric surface is also very widely used, and in fact, it is no more expensive than the spherical lens. For numerical control grinders, the wave surface can also be made.

Clearly, many people's understanding of the aspheric surface is still stuck in the leica 501.2 myth, which itself has long since been broken.

 

Of course, many people would still use the so-called "grinding aspheric", but don't say what grind the aspheric surface. I believe that for many people, it's impossible to tell whether a picture is not a spherical lens.

 

Is the aspheric surface necessarily good?

Even if it's a cock shot, it's impossible for each lens to be aspherical, the aspheric lens is actually a supporting role in the lens, not the main character, the main corrective, the correction function, after the use of aspherical lenses, the image of the edge of the image will be solved well and the picture will be more average.

 

So, is it a good thing to have an aspheric surface? From the current situation, the use of aspheric surface technology has become the standard configuration, especially the high technology index lens, for example, large aperture wide-angle zoom lens, it is difficult to guarantee the quality of the picture without the aspheric surface.

 

But in terms of our film fans, the aspherical lens we can use is relatively limited, after all, we use the camera mainly concentrated in the last century 60-90s, until the 90s, aspherical lens or less. Here we're talking about 135, and less in 120. We have seen that CAI has built so many classic Hau shots, such as the 384.5 on SWC, and there is no aspherical lens.

 

Still finding aspheric lens manufacturers at competitive prices? Explore Hypoptics.

 

In a series of SLR lenses designed by Mr. CAI for nikon, many of them have no aspheric surfaces. But it doesn't prevent these lenses from being a good shot, like chase 50, 1.4 SLR, and the picture is average.

 

Hyperion glass company is a premium full-service photonics supplier. Our manufacturing capabilities span across the spectrum. From UV, VIS, to IR, we fabricate custom optical components to system assemblies that meet unique and specialized applications.

 

How to Design and Manufacture Aspherical Lens?

 How to Design and Manufacture Aspherical Lens Design?

 

Aspheric fabrication is different from traditional spherical fabrication. In traditional spherical manufacturing, the surface is defined by a single radius of curvature. Curvature can be ground and polished using large tools. This polishing tool smoothes the relative curvature of the finished product surface into the desired shape by oscillating and polishing the curvature center of the medium such as slurry.

 

1. Selection of aspheric lens design materials

CNC and MRF optical glass and crystal materials; in addition, plastics can be chosen. Diamond turning is suitable for crystals, plastics and metals. Diamond turning works well for infrared optical materials and is inherently insensitive to higher surface roughness. Precision glass forming is limited, transition temperature < 500 degree C and thermal expansion coefficient of glasses are low enough, in a very limited choice of glasses. Choices have increased dramatically over the past decade, but still account for only a small fraction of all available optical glasses.

 

The glass softening temperature is lowered to room temperature in the forming process. In a short time, the glass is annealed and its index is lowered. This decline means that finished lenses will not have the same index as the glass catalogue specification. When designing precision glass moulding, users need to consider the low index in their models.

 

2. Design of curvature radius of aspherical lens

Compared with spherical lenses, aspherical lenses do not have a single radius of curvature. The edge change of the central part of the radius of local curvature. This leads to the possibility that the local radius of curvature can change the different points of its symbols from convex to concave on the surface, as shown in Figure 3. The place where the point occurs is called a turning point, which may lead to mold and measurement problems. In Zemax software, the cross section of the surface curvature can be used to check the local curvature radius of the surface.

 

As a custom lens design company, we will do our best to meet all the needs of customers.

New Crystal Glass may Allow Humans to Breathe Underwater like Fish

 The core problem of underwater activity of divers is that humans cannot ingest oxygen from water, therefore, it is necessary to carry gas cylinders or to supply gas from the water surface, and the breathing problem has become one of the most complicated technologies in diving technology. But the water actually dissolves a certain amount of oxygen, fish is through the gills to absorb oxygen from the water to maintain life. In theory, if you can master the rapid uptake of oxygen from water, then humans do not need to carry gas in the underwater activities. But keeping breathing for a long time under water has always been considered unthinkable and impossible, scuba diving can only continue to be carried out underwater by carrying air or by piping. Because fish can absorb oxygen from the water by their gills, humans and mammals don't have gills, and they can't use oxygen in the water to support life.

 

Let the human fish breathe oxygen in the water for a long time to survive in the water, it sounds like science fiction, and Danish scientists have recently been able to get oxygen permanently underwater, which is a step toward that goal. It's because of the kind of crystal material they developed, this synthetic material is named Neptune crystal AquamanCrystal. This synthetic material can continuously ingest oxygen from air and water without any other means. The oxygen absorbed by the crystal can be released as long as it is heated slightly or exposed to low oxygen pressure. At present, it is difficult to produce this kind of synthetic crystal material in large quantities.

 

The implications of this finding are profound, says Christina Mackenzie, a professor at the university of Denmark, who led the research. She told the science daily: "this material can absorb oxygen from the air. Patients with respiratory dysfunction need daily oxygen, the technology will allow patients to get rid of heavy oxygen tanks. Divers may also use the technology in the future to carry a small amount of this crystal grain. The diver breathes the material into the water to absorb oxygen that is dissolved in water, so there is no need to carry gas cylinders or supply the gas from the water. So they named the crystal AquamanCrystal.

 

Neptune crystals have a spongy composition that absorbs oxygen.

 

Neptune crystals absorb oxygen and rely on cobalt ions. This is very similar to the ability of hemoglobin to absorb oxygen. Because oxygen is difficult to dissolve in water and blood, all living things on earth use metal ions to combine and transport oxygen. The hemoglobin in the blood of people and many animals depends on the combination of iron and oxygen. Myoglobin, the myoglobin in muscle cells, is also a similar molecule. Animals such as crabs and spiders rely on copper ions to combine and transport oxygen. The ability of metal ions to absorb oxygen is huge. So it's not surprising that this crystal glass has a powerful ability to absorb oxygen.

 

If you want to know more about how fish breathe underwater, please visit our website.

 

Hyperion Optics is a premium full-service photonics supplier. Our optics manufacturing capabilities span across the spectrum. From UV, VIS, to IR, we fabricate custom optical components to system assemblies that meet unique and specialized applications.

Composition of Different Achromatic Doublet Lenses

 Composition of Different Achromatic Doublet Lenses

 

1. Achromatic doublet lens is a kind of common lens. It consists of several groups of positive and negative cemented lenses with different radius of curved surface. It can only correct the axial chromatic aberration of red and blue light in spectral line. At the same time, the spherical aberration on the axis and the coma aberration on the paraxial point are corrected. This kind of lens can not eliminate the second-order spectrum, only the spherical aberration and chromatic aberration in the yellow and green wave regions are corrected. The spherical aberration and chromatic aberration of the remaining chromatic aberration and other wave areas can not be eliminated, and the image field bending is still very large, that is to say, only the clear image in the middle of the field of view can be obtained. It is advisable to use yellow-green light as illumination source or insert yellow-green filter in the optical path. This kind of lens is simple, economical and practical. It is often used in conjunction with correction eyepiece and is widely used in medium and low power microscopes. In black-and-white photography, green filters can be used to reduce the residual axial chromatic aberration and obtain good contrast photographs.

 

2. Complex achromatic doublet design lens is composed of several groups of advanced lenses made of special optical glass and fluorite. The axial chromatic aberration is corrected by red, blue and yellow light, and the secondary spectrum is eliminated. Therefore, the image quality is good, but it is difficult to process and calibrate many lenses. The correction of chromatic aberration is in all wavebands of visible light. If blue or yellow filters are added, the effect will be better. It is the best objective in the microscope. It has good correction for spherical aberration and chromatic aberration. It is suitable for high magnification. However, it still needs to be used with compensating eyepiece to eliminate residual chromatic aberration.

 

3. Planar achromatic doublet lens is a complex optical structure composed of multiple lenses, which can correcting astigmatism and image field bending well, and make the whole field of view clear. It is suitable for microphotography. The correction of spherical aberration and chromatic aberration of the objective is still limited to the yellow-green wave region, and there is still residual chromatic aberration.

 

4. Planar achromatic doublet lens has the same degree of aberration correction as complex achromatic objective lens except for further image field bending correction, which makes the image clear and flat. But the structure is complex and difficult to manufacture.

 

Hyp design is a premium full-service photonics supplier. Our manufacturing capabilities span across the spectrum. From UV, VIS, to IR, we fabricate custom optical components to system assemblies that meet unique and specialized applications.

 

Calcium Fluoride Lenses

 Calcium Fluoride Lenses

 

Calcium fluoride lenses can also be fluorite lens. Fluorite is made of CaF2 crystal. Its obvious characteristics are low refractive index and dispersion, good transmittance for infrared ray and ultraviolet ray. The bigger concern is it has colorful and exquisite description performance while general optical glass can not achieve.Because light ray which gets through general lens will give away and reduce the acuity of image, we call it chromatic aberration. Fluorite lens suits taking lens best because of its little dispersion without chromatic aberration. Through adopting fluorite lens with low refractivity, it can drastically shorten the length of telephoto lens with high quality image.

 

The material of fluorite lens is fluorite, its main ingredient is CaF2 with much impurity. Natural fluorite is always with vivid color, its hardness is lower than knife. Fluorite is a kind of good optical material, lens that made of fluorite is with excellent optical quality, especially in the aspect of dispersion resistance, it is better than all other optical material.

 

Hyperion's manufacturing capabilities span across the spectrum. From UV, VIS, to IR, we fabricate custom optics prototyping components that meet unique and specialized application requirements. Our quick turnaround is a compelling advantage for Low Rate Initial Production (LRIP) projects.

Basic knowledge of aspheric lens technology

 Basic knowledge of aspheric lens technology

1、Technical principle

The curvature radius of the plastic aspheric lens changes with the center axis. It can be used to improve optical quality, reduce the number of optical components and reduce design costs. Compared with spherical lens, aspheric lens has unique advantages, so it has been widely used in optical instrument, image and photoelectron industry, such as digital camera, CD player and high end micro instrument.

2、Comparative advantage

a, Spherical aberration calibration

The most remarkable advantage of aspheric lenses in replacing spherical lenses is that they can correct the spherical aberration caused by spherical lenses in collimating and focusing systems. By adjusting the surface constant and the aspheric coefficient, the aspheric optics can eliminate spherical aberration to the maximum extent. Aspheric lenses (rays converge to the same point and provides optical quality) basically eliminate spherical aberrations produced by spherical lenses (rays converge to different points and leads to blurred imaging).

Three spherical lenses are used to increase the effective focal length, which can be used to eliminate spherical aberration. However, a aspheric lens (high numerical aperture, short focal length) can be realized, and it can simplify the system design and provide the light transmittance.

b, System advantages

The aspheric lens simplifies the elements involved in optical engineers to improve the optical quality and improves the stability of the system.For example, in zoom systems, 10 or more lenses are normally used (additional: high mechanical tolerances, additional assembly procedures, and the improvement of antireflection coating). However, one or two aspheric lenses can achieve similar or better optical qualities. This reduces the system size, increases the cost rate and reduces the overall cost of the system.

3、Moulding techniques

a, Moulding of precision glass

The molding of precision glass is to make the glass material heated to high temperature and become plastic, and then molded by aspheric mold, and finally gradually cooled to room temperature.At present, the molding of precision glass is not suitable for aspheric lens with diameter greater than 10mm. However, new tools, optical glass and metrology process are driving the development of the technology. Although precision glass molding at the beginning of the design has high cost (high precision mold development), but after the molding, the production of high-quality products can be split off the pre development costs. It is especially suitable for the needs of mass production.

b, Forming of precision polishing

Lapping and polishing are generally applicable to the production of monolithic aspheric lenses at one time. With the improvement of technology, the accuracy is higher and higher.The most remarkable thing is that precise polishing is controlled by computers and automatically adjusted to optimize parameters.If higher quality polishing is required, magnetorheological finishing (magneto-rheological finishing) will be adopted. Compared with standard polishing, magnetorheological finishing has higher performance and shorter time.Precision polishing molding technology need professional equipment. It is currently the first choice of sample production and small batch sample.

c, Hybrid molding technology

The hybrid molding is a spherical aspheric lens with a spherical lens as the substrate, which is cast on the surface of the spherical lens through an aspherical mould and cured by a layer of high polymer with UV light.Mixed forming is generally used the achromatic spherical lens as the base, and then a layer of aspheric surface is cast on the surface to eliminate chromatic aberration and spherical aberration simultaneously.Figure 7 is the manufacturing process of the hybrid aspheric lens. The hybrid aspherical lens is suitable for large scale manufacturing with additional characteristics (eliminating chromatic aberration and spherical aberration) .

d, Injection molding

In addition to glass aspherical lenses, there are plastic aspheric lenses.Plastic molding is the injection of molten plastics into aspherical molds.Compared with glass, the thermal stability and compressive resistance of plastics are poor. It requires special treatment to obtain similar aspherical lenses. However, the plastic aspheric lens is characterized by its low cost, light weight and easy molding. It is widely used in the fields of moderate optical quality, insensitive to thermal stability and little pressure resistance.

4、Basis of choice

All kinds of aspheric lenses have their own relative advantages. Therefore, it is very important to choose the right products for different applications. The main considerations include: batch, quality and cost.

As a hyperion glass company, we will do our best to meet all the needs of customers.

Advantages and Disadvantages of Aspherical Lenses

 Advantages and Disadvantages of Aspherical Lenses

 

The surface radian of aspherical glass lens is different from that of ordinary spherical lens. In order to pursue the thinness of the lens, it needs to change the surface of the lens. Aspheric lens should be designed as flat as possible. However, the optical properties of flattened lenses, even if they are designed with aspheric surfaces, will decline rapidly. At the same time, the lens is lighter, thinner and flatter, and it still maintains excellent impact resistance, so that the wearer can use it safely.

 

Advantages of aspherical lenses:

1. Optical advantages: reduce the aberration of the lens and make the vision clearer.
2. Clear images can also be obtained at high luminosity: Although the spherical point focus lens is designed by the best base arc, the luminosity beyond + 7.00D-22.00D is not within the Cherning ellipse, and the aberration can not be eliminated. Only aspheric design can achieve better quality.
3. It can make the lens flatter, thinner and more beautiful. The higher the lenticity of spherical lens, the worse the appearance. Aspheric lens can be designed with flat base arc, which not only makes the appearance beautiful, but also reduces the peripheral magnification. Let others see the wearer's eyes, will not change a lot in size.

 

Defects of aspherical lenses:

1. Aspheric lens has a relatively small light area. When the eyeball rotates around, it will blur a little when looking at the outside through the lens edge, that is, the visual range of the line of sight becomes smaller.

 

2. Human's eyeball is spherical. The eyeball rotates to the edge. Through aspheric lens, the object near the eye appears protruding.

 

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