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hypoptics April 23

Cylindrical Lens can be used in a single axial convergence or divergence of the beam and found in optical measurement, laser scanning, spectroscopy, laser diode output beam shaping, the X-ray light microscopic imaging, and many other industries and fields have a wide range of applications.
Turn the quasi-direct light source into the line light source
L = 2(r0/f)(z+f)
It is the most extensive application of cylindrical lens. As shown in the figure below, The quasi-direct light source with radius r0 is irradiated into a concave cylindrical lens with a focal length of -f(The image is in order to illustrate the principle more clearly, so amplify the beam radius). The beam will diverge in half theta (theta = r0 / f). At this point, it can also be approximated as the divergence of the point source at the focal point -f. The distance to the back of the lens is z. The width of the line beam is 2r0 (ignoring the divergence of the Gaussian-distributed beam spot), but the length of the line beam is changed
L = 2 (r0 / f) (z + f)
When z is greater than f, the expansion ratio approaches z/f, and the length of the line is proportional to z.
If need in the z produces width is very narrow line light source, can be in the plane concave cylindrical lens front end or back end of a flat convex cylindrical lens focal length for z, with the orthogonal plane concave cylindrical lens place, to compress the beam width.
【 Quick Start】The focus and alignment of light
The diode outputs beam of collimation
The laser diode output beam diverges in an asymmetric form, and its quasi-direct work is more challenging. for example, to divergence angle theta. Theta 1 x 2 = 10 ° x 40 ° diode light source, if only use the standard spherical lens, and only in a single direction on collimating, another direction divergence or convergence will happen. Using a cylindrical lens that the problem is decomposed into two one-dimensional directions, through the combination of two orthogonal cylinder lens, two directions can be collimated at the same time.
The selection of the cylindrical lens and the installation of the light road should follow the below rules:
θ1/θ2 = 10°/40° = f1/f2
1)To make the spot symmetrical after the adjustment, the focal length ratio of the two cylindrical lenses is equivalent to the divergence angle.
Theta 1 / theta 2 = 10°/ 40° = f1 / f2
2)The laser diode can be approximated as a point source, to get the collimating output, The spacing between the two cylinders and the light source is equal to the focal length of the two.
3)The spacing between the main planes of the two cylinders should be equal to the difference between the focal length of the f2-f1, and the actual spacing between the two lenses is equal to BFL2 - BFL1. Like the spherical lens, the convex side of a cylindrical mirror should be directed toward a quasi-direct beam to minimize as much as possible.
d1 = 2f1(tan(θ2/2))
d2 = 2f2(tan(θ1/2))
4)Because the laser diode output beam diverges faster, we need to be careful to confirm that the spot size on each cylinder is no longer than the effective light aperture of the lens. Because the distance of the cylinder is equal to its focal length, the maximum spot width of each cylinder should be followed
D1 = 2f1 (theta 2/2)
D2 is equal to 2f2, the tangent of theta one half.
For example, Newport CKX012 (f1 = 12.7 mm, BFL1 = 7.49 mm) and CKX050 (f2 = 50.2 mm, BFL2 = 46.03 mm) the combination of cylinder lens, the spacing between the two lens on the plane for BFL2 - BFL1 = 38.54 mm. The diameter of the spot in the first cylindrical lens is
D1 = 2 (12.7 mm) tan (20 °) = 9.2 mm
The diameter of the light spot in the second cylinder is
D2 = 2 (50.2 mm) tan (5 °) = 8.8 mm
Although there is still a little asymmetry, the simple combinations of these two cylindrical lenses have greatly improved the quality of the beams.
Hyperion Optics always believes in the concept of bringing “Precision, Performance, Satisfaction, Cost-wise products” to our customers to meet the expected procurement experience. We are not simply manufacturing components and lenses, but delivering a comfort and worry-free user experience with outstanding quality assurance promise to you.

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hypoptics April 23

The aspheric
When it comes to the lens, you have to mention the aspherical lens. In many people's understanding, the asperical 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.
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.
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hypoptics April 23

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 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.
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  • Composition of Different Achromatic Doublet Lenses
                                        1. Achrom... via hypoptics

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