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In the summer, many people will choose to wear sunglasses. When buying sunglasses, do not only pay attention to whether they are fashionable or not. Different types of lenses are also important points that cannot be ignored.sunglasses customDifferent types have different effects. So what are the types of sunglasses?
Here are some common lenses
1: Polarized lenses
The term polarized light is used a lot in sunglasses, but many people do not understand the specific meaning. In fact, this kind of lens is used to filter the glare from the sun in equal directions, and a special vertical coating is added to the lens. It is very suitable for outdoor sports (such as marine activities, skiing or fishing).
2: Color changing lens
Another name is "photosensitive lens". Originally transparent and colorless lenses, when exposed to strong light, they will become colored lenses to protect the eyes. This is because silver halide chemicals are added to this type of lens, so it needs to be used indoors and outdoors at the same time. , It is very suitable.
3: Anti-reflective protective lens
This kind of lens can prevent the reflection of strong light, allowing you to see things undisturbed under strong light, and more clearly. The principle of this kind of lens is actually very simple, that is, a layer of magnesium fluoride is coated on the surface. If you want to know whether your sunglasses are anti-reflective protective lenses, you can point your glasses at the light source. When you see purple or green reflections, it means that there is an anti-reflective protective film on the lenses.
4: Colored lenses
This kind of lens is also called "tinted lens." Sunglasses using this kind of lens can absorb light of a specific wavelength. The principle is to add some chemicals in the lens manufacturing process to make the lens appear colorful. This kind of lens is most commonly used in sunglasses.
5: Painted lenses
The effect of this kind of lens is actually the same as that of a colored lens, but this kind of lens is generally used in sunglasses with power. The most familiar one is the "graded colored lens", the color is from top to bottom. From deep to shallow.
Finally, when you buy sunglasses, in addition to looking at the corresponding types, you must also pay attention to the material selection of the glasses. Generally, spectacle lenses are divided into resin, glass and crystal. Both lenses and frames should have a shelf life. It is also important to read the product quality inspection certificate, the name of the manufacturer, and the address of the purchased glasses. At the same time, you must ask for the purchase invoice. In the event of a quality problem, you can protect your legitimate rights and interests.
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1. Pay attention to the labeling of product performance indicators
When buying earphones, pay attention to the performance indicators on the earphone packaging or manuals, because poor-quality earphones are often produced by small factories, and some of their performance indicators are randomly labeled, and some are exaggerated. Headphones generally have a low frequency range of 20-20kHz, a power greater than 100mW, and a harmonic distortion less than or slightly equal to 0.5%. If the above requirements are not met, it is recommended that you still do not buy. It is recommended not to buy a product whose performance is too high in the manual.
2. The quality of product workmanship
The more authentic earphones produced by major manufacturers usually use engineering plastics, so they have a very smooth appearance, and have a certain degree of stress and toughness; headphones with memory card hey have no harshness, fine workmanship, and no roughness of inferior plastics. In addition, the lead wire diameter of the earphone is relatively thick, which can ensure stable transmission, and the wire feels soft and hard; the plug is made very clean and neat, without leaving burrs, and the coating is smooth and even. If the above conditions are not met, it is recommended not to buy.
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LHD company provides a comprehensive assembly cable. Whether it is radio frequency cable assemblies for mass production, corrugated pipe cables for outdoor applications, laboratory test cables or high-precision test and metering cables. LHD provides customized cable assembly and adjusts the manufacturing process as needed. At the same time, LHD is committed to the research and development of new products, promoting the development and progress of assembly technology.
Automated cable assembly
Fully automatic cable assembly From the product development stage, the structural design of cable components has been carefully considered and repeatedly verified to ensure that difficulties and obstacles are cleared for the automation team.custom cable assembly
The conceptual stage of product development defines all steps from engineering design to fully automated assembly machines.
Manual cable assembly
Manual assembly requires understanding and mastering every detail step in the entire assembly process, which is also a prerequisite for partial and fully automated assembly. LHD's reasonable layout of cable assembly methods can meet the needs of all products from a single cable to large-scale production.
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Did you know that almost all gadgets or electronic devices you use in your daily life have a common basic element? Almost any electrical system, as well as your computer, laptop, smart phone, network game console, microwave oven, TV, dishwasher, etc., will not work properly without PCB assembly. So, what is PCB assembly?
With an increasing number of companies in China seeking to expand their customer base and compete in international markets, particularly the high-growth industries in the Asia Pacific and beyond, offering a complete range of Pcb assembly service in China will provide a vital edge over local competitors.
What does PCB structure mean? PCB assembly refers to the process of soldering and assembling electronic components, pads and manufacturing printed circuit boards (PCBs) on prefabricated parts. Professional production machinery is usually used for mass production. The printed circuit board assembly process is commonly referred to as PCBA.
The difference between PCB and PCBA
PCB refers to the empty circuit table. In this state, the circuit meter does not contain any electronic digital components and looks similar to an environmentally friendly slate with split outlines and spots. Therefore, unless of course, the PCB itself cannot be used for work until the complete construction is completed.
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Brightness and contrast: Brightness and contrast can be said to be the most basic conditions for judging the quality of liquid crystal displays. Usually the screen has a higher brightness value to make the picture brighter, and the LCD screen needs a brightness value of at least 200cd/m2 to display a picture that meets the basic requirements. Of course, the higher the brightness value, the better the performance. The picture is also more vivid.
Contrast refers to the brightness contrast between black and white colors. In other words, a high-contrast liquid crystal display can display richer color levels. Basically, the contrast index of the liquid crystal display must be at least 200:1, otherwise, uneven color blocks may appear when displaying pictures with the same color gradient, and the display texture is poor. Of course, the higher the value of this indicator, the better.We are the lcd manufacturersfor small size displays such as 1.8inch 128x160, 2.0inch 176x220, 2.0inch 240x320 IPS, 2.8inch 240x320, 3.5inch 320x240 and 3.5inch 320x480 IPS ect.
Signal reaction time: The signal reaction time refers to the time required for each pixel of the liquid crystal display to go from dark to bright and from bright to dark. The general specification indicates the average value of the above two, but some manufacturers will list both values. For consumers who want to use LCD to play games and watch movies, this data is very important. If the signal response time is too long, the dynamic picture is prone to afterimages, and the display effect will be greatly reduced.
Generally speaking, the signal response time of the current liquid crystal displays on the market should be below 30ms, and even models below 15ms can be seen everywhere. If the user has a large number of dynamic picture needs, such as game players, it is best to choose a product with a shorter response time.
In addition to the proper nouns that often appear in the manual, there is an important criterion for the quality of LCD monitors: the number of bright spots. The so-called bright spot is a pixel (pixel) that is continuously lit and does not accept the extinguishing signal, which is also called a dead pixel. Bright spots are usually not easy to spot, and users have to watch them carefully in a completely black screen to find them.
The bright spot can be said to be a unique problem of liquid crystal displays. Its cause is: in the process of manufacturing the LCD panel, the good rate cannot reach 100%, so there will be a bright spot problem when leaving the factory. Generally speaking, the number of bright spots of A-level panels is limited to 3 or less, and some brands also offer no bright spot guarantee. If the bright spot exceeds the quantity standard specified by the manufacturer, it can usually be replaced with a new one.
To check whether the LCD display has bright spots, you can use graphics software (the simplest tool is the drawing that comes with Windows) to draw a black picture, and zoom in to the full screen state (such as 1024X768 resolution), and then carefully check the screen Are there any shiny dots? In addition, after a long period of use, liquid crystal displays sometimes gradually appear bright spots. Therefore, after consumers get the product, they may wish to start the test for a few days. If during the replacement period (usually 7 days), the number of bright spots exceeding the replacement standard is found, the merchant can be required to replace the new product.
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