Several knowledge of eyeglass frames
Spectacles are one of the optical metrology products widely used in people's lives. They consist of lenses and frames. Strictly speaking, the spectacle frame is not a metering product, but as an important accessory, the quality of the spectacle frame has a direct impact on the outfitting and use of the spectacle. Therefore, the national standard GB/T 14214-2003 "spectacles frame" of the People's Republic of China specifies the technical requirements and test methods for each parameter of the spectacle frame.
Frame classification
First, the common frames can be divided into plastic frames (including natural materials), metal frames, and hybrid frames.
1. Plastic frames: Its characteristics are: light weight, not allergic, more loved by the elderly, children, and now is also the fashion crowd as a choice of sunglasses or decorative mirrors.
At present, plastic frames are mostly made of acetate resin, which is made of laminated plastic, and is made by laminating one color of thin layer plastic on another layer of thick plastic, and the thick material is mostly transparent (or Translucent pigments are also made from three or more layers of plastic.
The natural materials for the spectacle frame include enamel, special wood and animal heads. The common one is a spectacles frame.
The oyster material is made of clam shells produced in tropical seas and is mainly produced in the West Indies. Its advantages are light weight, beautiful luster, no irritation to the skin, long-lasting preservation value, very popular among middle-aged male wearers. The disadvantage is that it is relatively easy to break, but it can be bonded and repaired after breaking. In the use of maintenance can not be used ultrasonic cleaning, otherwise it will be white and tarnished. Since it is an animal that is prohibited from catching in the ocean, it is rare and expensive.
2. Metal frames: Its characteristics are: strong, lightweight, beautiful, fashionable and variety.
The material of the metal frame is made of a certain metal material or alloy, and copper alloy is used as the substrate. The surface treatment of the metal frame is often gilded or plated with white or titanium with rhodium or palladium. Due to different electroplating processes, some tend to fade and some do not fade easily. There are also frames made of pure titanium and frames made of memory alloys.
Metal frames are basically equipped with nose pads, and the nose pads are movable to accommodate various nose shapes. Plastic sleeves are often put on the ends of the temples, not only aesthetic, but also protect the temples and the skin.
3. Hybrid material rack: Its characteristics are: exquisite shape, beautiful, gives a sense of elegance, because the outer layer of plastic closely contacts the inner metal material so it is not easy to burn, increasing the strength of the frame.
The material of the hybrid material frame is made of a mixture of metal and plastic. Some of these frames are plastic wrapped in metal; others use different materials in different parts of the frame, that is, the front frame is plastic, the temples are metal, or the front frame is metal, and the temples are plastic. The combination of the above two methods, such as the use of plastic eyebrows and nose, stainless steel frame material, metal plastic temples wrapped in plastic.
Second, the common frame according to the shape of the main points are full-frame frames, half-frame frames, rimless frames, eyebrow frames, combined frames and folding frames.
1. Full-frame frames: The full-frame is a more commonly used type of frame, characterized by a solid, easy-to-shape, can cover a part of the lens thickness.
2. Half-rim frame: The half frame is made of a thin nylon wire as a part of the frame edge. The lens is specially ground to flatten the bottom edge of the frame. A narrow groove is formed in the bottom edge to make the nylon wire embedded in the groove. The bottomless frame style is characterized by its light weight, giving a sense of lightness and chic, and it is also more solid.
3. Frameless frame: no frame without mirror ring, only the metal nose and metal temples, the lens and the bridge of the nose and the temples are directly connected by screws, generally in the lens drilling. The non-frame is lighter and more chic than the ordinary frame, but its general strength is slightly inferior to that of the full frame.
4. Eyebrow frame: eyebrow frame is similar to half frame frame. The upper half frame has only one eyebrow like eyebrow, with a very thin nylon wire as the lower part of the frame edge, the style is more fashionable.
5. Combination frames: There are two sets of lenses at the front frame of the combined frames, one of which can be turned up, usually for indoor and outdoor use.
6. Folding frames: frames can be folded into four or six fold, mostly reading glasses.
Choosing Optical Frames and Metering Tips
When an ordinary consumer selects a spectacle frame, he or she usually notices only the aesthetic problem. In fact, the optical and metrological specifications of the spectacle frame are very important for the comfort of the wearer. The selection of frames must meet optical and metrological requirements.
1. The geometric center size of the spectacle frame is preferably close to the pupil distance of both eyes (less than 4 to 10 mm is preferred).
Considering that the blank of the lens must pass through the center cutting edge to be able to mount the frame on the front, the position of the pupil is preferably right to the geometric center of the spectacle frame, preferably less than 4 to 10 mm. If the lens shift center is very large, it may cause prisms and other effects, affecting the comfort of wearing glasses.
2. After wearing the lens, make sure that the distance from the lens to the eyeball is about 10mm.
If the lens is too far from the eye, not only the optical effect changes, but also the wearer will see the outside of the lens, causing difficulty in positioning; if the lens is too close to the eye, the eyelashes will touch the lens, which will not only cause the lens to be blurred, but also cause irritation. Therefore, after wearing glasses, it is best to ensure that the distance from the lens to the eyeball is about 10mm.
3. The angle between the front mirror of the glasses and the vertical line of the wearer's face is about 4° to 18°.
The size of the angle relates to the field of vision. In general, the upper part of the frame cannot touch the eyebrows, and the lower part cannot touch the face. If the frame does not reach the required forward rake angle, it is advisable to ask a professional to adjust the septum or replace the frame.
4. The width of the nose bridge of the glasses is moderate.
When the consumer selects a spectacle frame, it can be detected by the following method: Keeping the head vertically and looking forward, the frame can maintain a satisfactory position without any grip of the temple.
If the bridge is too narrow, not only the lens will be in front of the eye too high, but also the nose frame and nose contact parts will be uncomfortable, and even cause the nose skin tissue temporarily recessed; if the nose bridge is too wide, the lens will fall too low, the mirror It is impossible for the legs to maintain the normal position of the spectacle frame for a long time.
5. The length of the glasses legs is moderate.
In principle, the curvature of the temple should be exactly above the fold of the ear, but pressure should be avoided on the part of the ear fold.
If the length of the temple is not enough, the glasses will tilt upwards, and the tail of the spectacle frame will press into the back of the ear, making the wearer feel uncomfortable; if the length of the temple is too long, when the head is tilted, the tail of the spectacle frame will come into contact with the back of the ears. Fall down on your own.
It is worth noting that when trying glasses frames and estimating the length of the temples, the frame should be kept at the correct anteversion angle on the face. If you do not consider the anteversion angle when you try on it, you will feel the length of the temples for a long time. too short.
6. The deeper the negative refraction (commonly known as the degree of myopia) is better.
7. In general, astigmatism should not use round frames.
8. Taking into account the visual aberrations, prisms and other effects, the average consumer is best not to choose too large arc frame.
9. For children, you can choose a transparent frame without a nose pad, high nose pads will more show the characteristics of the nose than the collapse.
In addition, it is worthy of special reminder that if consumers often wear metal frames of glasses, suddenly replaced with plastic frames, or vice versa, just wearing will have to adapt to the feeling. This is because metal frames generally have nose pads. There is a nose pad to adjust the vertical distance between the lens and the eyeball. Often metal frames are more suitable for metal frame distances, and the plastic frame has no nose pads, so the distance is Unable to adjust, just wear will not adapt to the feeling. Generally about one week is the period of adaptation, and the feeling of discomfort after the acclimation period will gradually disappear or be significantly relieved. If there is still no relief, it is advisable to consult a professional or re-use the original frames.
Tips for picking up eyeglass frames
When selecting a spectacle frame, you can check the appearance and feel of the spectacle frame.
Consumers can first look at the quality of the frame from the overall fineness of the frame, the degree of finish, the degree of Spring recovery, the flexibility of the temples, etc., and then pay attention to the degree of Screw tension, welding process, whether the frame is symmetrical, size Whether the label is standardized or other details to comprehensively determine the quality of the spectacle frame.
When choosing a spectacle frame, you should pay attention to the fitting process.
Try to wear glasses frames, not only should pay attention to whether it is beautiful, but also pay attention to whether the optical frames meet the measurement requirements, whether to match the facial skeletal structure of the wearer, pay attention to whether the stress point of the face to maintain uniform, stable support, whether Keep the lens in a good position and comfortable.
This news comes from China Spectacle Trading Network/
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