What makes a good pair of sunglasses?
In the previous article, we discussed “How come it is harder to see traffic lights when I'm wearing polarized sunglasses?”. In this article, let’s talk about “What makes a good pair of sunglasses?”.
The production of glasses sounds like a very easy thing, but is it really that simple in fact? The production process of the glasses determines the quality of the glasses we wear. So, do you know how the glasses are made?
Manufacture Of The Frame and Temples
Cut Out The Frame
Before cutting the plastic board, we will heat it first. Heating can improve the ductility of the material. Press with a steel knife. And cut out the outline of the frame on the plastic board. Then follow the inner curve to cut out the inner frame.
Cut Out The Groove
Continue to deal with the inner frame to create a groove for placing the spectacle lens. Using a blade in the frame to cut out the groove which is used to lock the spectacle lens.
After cutting out the exterior of the glasses, it needs to be transferred to another cutting machine. According to the model, cut the three-dimensional shape of the nose bridge.
Polishing The Frame
Now put the frame in the roller filled with sanding stones to rotate. This is the step of polishing. After finish this step, you can feel the edges of the frame to see if there is any roughness.
The temples are also made of plastic plates. So the procedure of making temples is the same as the frame. Cut the material after heat the plastic plate. And then the outline of temples comes out. After that, we have to reheat the temples to insert the steel wire core as the backbone of the temples.
Connect Frame With Temples
The last step is to connect the frame with the temples. Insert the connector on the edge of the frame, and then connect with the temples with screws.(https://www.koalaeye.com/blogs/our-stories)
Manufacture of Sunglasses Lenses
When produce the lenses, we need to add colorant compounds into the glass raw material powder. By this way, the dark sunglasses can absorb more light to reduce the intensity of sunlight. The shearing machine first cuts a section of high-temperature molten glass, which is the main body of the lens. And a stamper presses it into an arc-shaped lens.
We need to send the lens to chemical treatment. Through the ionic exchange, a metal coating is plated on the surface of lens.
In this step, lens will be sent to make the final shape, which is to fit the spectacle frame you choose. Different frames have different lens contours.
Some lenses also have a reflective coating on the outer surface. This coating which is a bit like a mirror for the lens can help to reflect sunlight to protect the eyes. However, unlike the silver plating made by mirrors, this coating is very sparse. So it is also called semi-silvered.
Install the lens
Do you know how the lens was inserted into the plastic frame in the factory? The lens is just directly inserted into the frame. Put one side of the spectacle lens into the groove on the nose bridge of the frame first. And then heat it slightly, so the spectacle frame will be malleable. At this time, the lens can be directly inserted into the frame.
What are the requirements for a good pair of sunglasses?
1. It can absorb ultraviolet light with a wavelength of 400mm or less.
2. It should cover the area around the eye socket to the temple, so that the sun will not enter from the side.
3. The color of the lens should be consistent. It should not be darker in one area and lighter in other areas.
4. Another way to determine the quality of sunglasses is to hold the sunglasses one arm away from yourself, and then look at distant objects such as walls and bookcases through the lenses from this distance. When moving the lens horizontally, pay attention to whether the distant object is distorted, shaken or moved or not. If this phenomenon occurs, don’t buy these sunglasses.
5. The color of the lens is better to choose gray, green or brown.
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