Principles of special glasses
Reading glasses (hyperopia glasses)
The principle is similar to that of a myopic lens, except that it is a convex lens. The function is to make the parallel light rays in the distance converge appropriately by the convex lens and then refraction by the eye to form a clear image on the retina.
As the name suggests, it is "invisible". It not only has the function of ordinary glasses to correct vision but also relieves the inconvenience caused by frame glasses, so wearing contact lenses has become fashionable today. However, contact lenses are not suitable for all those who need lenses
Color changing glasses
The mystery of the color-changing glasses is in the glass. This special glass is called "photochromic" glass. In the manufacturing process, it is pre-mixed with light-sensitive substances, such as silver chloride, Australian silver (collectively referred to as silver halide), etc., as well as a small amount of copper oxide catalyst. The color of the spectacle lenses changed from no color to light gray and dark brown, and then from black spectacles to tone glasses. It is the magic of silver halide." In the glass of the color-changing spectacles, there are changes that are very similar to the exposure imaging of photosensitive film. Process. The silver halide decomposes when exposed to light and turns into many black silver particles, which are evenly distributed in the glass, so the glass lens appears dim and blocks the passage of light. These is black glasses. However, it is different from the situation on the photosensitive film. , The silver atom and halogen atom generated after the decomposition of silver halide are still close together. When returning to a darker place, under the promotion of copper oxide catalyst, silver and halogen recombine to produce silver halide, glass lens It became transparent again.
Crystal glasses are expensive, and they make people feel very cool after wearing them. Some people think that they have a nourishing effect. There is no scientific basis. Crystal was first used to make glasses because it was not possible to make optical glass at that time. Better optical material than crystal. It has been proved by scientific practice that double refraction occurs when light passes through the crystal, resulting in double reflection, and the effect of crystal blocking ultraviolet and infrared rays is not very good. Most of them can pass through. Crystal glasses are expensive It should be that the crystal geology is hard and brittle, not suitable for annihilation, and the low output of the pure crystal is not because it has a special maintenance effect on the eyes. People wear crystal glasses and feel cool because the crystal lens absorbs ultraviolet and infrared rays. The temperature is lower, but it does not. Eyecare. Glasses, eye care.
On the sports field, have you ever experienced or seen a scene where the eyes are injured by body collision or external force? Especially in some competitive sports, due to the fierce resistance of limbs and sports equipment, any small negligence and unintentional collision may cause permanent damage to the eyes. In addition to the traditional optical glasses, the eyesight The remedy of the lens does not really protect your eyes. On the contrary, there will be layers of safety risks. Under the action of external force, the frame and lens are very easy to fall off/deform or break (fracture) and damage the eyes. Eye injuries mainly include 1. Corneal scratches 2. Iris inflammation 3. Anterior eyeball hyperemia 4. Traumatic cataract 5. Retina swelling 6. Eye corner rupture, etc.
Frame: Designed for myopic basketball enthusiasts. The integrated frame is processed by high-tech technology. The width and curvature are more suitable for the characteristics of oriental faces. The corners are flexible, not easy to deform, and can more effectively protect the eyes and the bridge of the nose. The side wings are breathable. Holes make it safer and more comfortable to wear, and you can ride on the sports field without any scruples.
Nose pads: unique, soft, elastic, and anti-allergic silicone nose pads, so that the frame will not be too close to your face, and can effectively resist and cushion the impact on the eyes when you are in close contact with your opponents, and protect The eyes are not damaged.
Suitable for basketball, football, volleyball, tennis, rock climbing, cross-country, and other sports
3D glasses need to cooperate with 3D movies to be useful, watching ordinary movies is useless.
First, let me explain that light can be processed by polarization. The processed light has a polarization direction (the direction of the light itself is unchanged), but we still look like the original light.
Then there is a kind of lens called a polarizing lens. It also has a polarization direction. Lights with the same polarization direction can pass, but different lights cannot pass.
When shooting a 3D movie, two cameras are shot together at different angles (almost the angle where the eyes are separated). During the projection, the two sets of images are processed with different polarization directions and projected on the screen.
Night Vision Glasses
Night vision technology is a photoelectric technology that realizes night observation by means of photoelectric imaging devices. Night vision technology includes low-light night vision and infrared night vision. Low-light night vision technology, also known as image enhancement technology, is a photoelectric imaging technology that uses night-vision goggles with image intensifier tubes to enhance the weak target image illuminated by night light for observation. Low-light-level night vision is currently the largest and most widely used night vision equipment in foreign countries. It can be divided into direct observation (such as night vision observers, weapon sights, night pilots, night vision glasses) and indirect Observation (such as low-light TV) two kinds. Infrared night vision technology is divided into active infrared night vision technology and passive infrared night vision technology. Active infrared night vision technology is a night vision technology that implements observation by actively irradiating and using infrared light reflected by the target to reflect the infrared source. The corresponding equipment is an active infrared night vision device. Passive infrared night vision technology is an infrared technology that uses the infrared radiation emitted by the target itself to achieve observation. It finds the target according to the temperature difference or thermal radiation difference between the target and the background or parts of the target. Its equipment is a thermal imager. The thermal imager has unique advantages different from other night vision devices, such as Working in rainy, snowy weather, with long operating distance, ability to recognize camouflage and anti-interference, has become the focus of foreign night vision equipment development, and will replace low-light night vision to a certain extent.
Ski goggles are divided into alpine mirrors, jumping mirrors, cross-country mirrors, self-curving mirrors, etc. Due to the strong reflection of the sun on the snow, and the cold wind irritating the eyes greatly during sliding, ski goggles are needed to protect the eyes of skiers.
Ski goggles should have the following functions: first, to prevent cold wind from irritating the eyes; second, to prevent ultraviolet rays from burning the eyes; third, the mirror surface should not be fogged; fourth, the ski goggles should not cause damage to the face after a fall.
Detail Principles of the HEART DIFFRACTION GLASSES
The heart effect glasses come with many small circles attached to the lens. Where there are no small circles, it looks like a normal spectacle lens, and the small circles show the existence of some microstructures.
It is not difficult for us to imagine that it is the microstructure in the small circle that brings the halo in the shape of a love heart, while the ordinary area of the lens without the small circle is normally lighted. The light passing through the heart diffraction glasses is normally imaged so that we can still see the original. object. To put it simply, a "split pupil" is realized on the glasses-part of the light is still imaged in an original way, but the other part of the light is scattered into the shape of a love heart. (Of course, the light from the original optical path can also be transmitted through the small circle diffraction area. The 0-order diffraction definitely exists, and it can also realize the imaging of the original object. This is not the table below.) Let’s simplify the model of the problem. The street lamp at the place approximates it as a point source of parallel light incident at infinity. The diffraction area on the heart diffraction glasses can add a wavefront modulation to the incident plane wavefront, and the human eye (or mobile phone camera) is regarded as an ideal Imaging lens.
The diffraction area on the spectacle lens of the heart diffraction glasses can easily use some material patterns (microstructure patterns) to delay (modulate) the phase of each incident light. For example, if you want to delay the phase of the uppermost light by pi/2, you only need to paste material of λ/4(n-1) thickness on the place where the uppermost light is in contact with the spectacle lens. For ordinary spectacle lenses, the plane wavefront is incident and the plane wavefront is exiting. For spectacle lenses that use a diffractive surface (phase modulation), the outgoing wavefront can be modified into a variety of strange shapes. Here, in Zemax, the surface shape of the spectacle lens position is changed to a Binary 2 phase surface to simulate the additional phase applied and the final wavefront shape.
We know that the direction of light propagation can be obtained by deriving the wavefront, so we can see that the light on the image surface is scattered. These heart diffraction glasses also use the same principle. Through a special phase modulation, a designed wavefront is obtained. This wavefront corresponds to the image surface and becomes the shape of a love heart. (Then how to design the pattern of the phase modulation surface according to the final love pattern that I want to form? We can use an algorithm called IFTA (Iterative Fourier Transform Algorithm) iterative Fourier algorithm, or also called the Gerchberg-Saxton algorithm. achieve.