Three main factors that affect the light emitting effect of products

Posted on September 22, 2022 by Love Dome

Although we know LGF (light guide film) can have very good light emitting effect, but the scientific and accuracy of the light emitting effect can’t be detected by using standard instrument, because of its structure characteristics that we need to repeat and debug LGF product samples, so we need to find the factors that influence the LGF emitting effect that can avoid bad product light or uneven.

As shown below, the number keys 1,4, and 7 on the left are significantly darker than the number keys on the right, and the X, arrow character key on the right, is also significantly darker.

But once you find the reason and adjust it, you can turn it into the picture below. The brightness is even and the product looks comfortable.

Why the light emitting effect is so different with same product?

If the light conduction effect of the product is not good, it will bring the following problems:

1.  The visual effect of the product is affected, such as stray light, astigmatism, light leakage, ghost and other problems, which will make customers feel that the quality of the product is not good, and thus affect the customer’s experience of using the product.

 2.  It will increase the cost of product return, scrapping and maintenance, and seriously affect the company’s reputation.

 3.  Products gradually lose competitiveness and lose customers and markets.

 4.  The light guide of the product is not good, which not only affects the appearance, but also makes it inconvenient for customers to use, and naturally, they will not buy again

When we have a product with poor light guide effect, we usually think to change the whole product design or increase the qty of LED lights, such as adding LED lights in the dark area of the product. Although this method can solve the problem, it is time-consuming and energy consuming, and increases the cost, but it may not get the desired effect. So, we still need to understand why light is bad, then could solve the fundamental problem.

The reasons of poor light emitting effect of products:

1, It is related to the raw material differences between material PC and TPU of light guide film (LGF). When we choose raw materials, it is not the thinner or thicker with better, the thinner PC material will be with the greater light loss, but the feeling will be better, the thicker material will be with the smaller light loss, but the feeling will be poor, so we need to choose the right material according to the product.

2, The poor assembly of LGF and LED leads to poor light guide effect. Mainly due to the following reasons:

A: As structure in below, the thickness of LGF exceeds the height of LED, the light emitted by LED cannot shine on LGF well, so the light emitting effect is poor. The result may be there is light in the near light area, but no light at all in the far light area.

B: As structure in below, the distance between LGF and LED is greater than 0.2mm, and the LED light energy cannot shine on LGF well, the light emitting effect is poor. The phenomenon is that there may be a light in the near light area, but the light effect in the far light area is very poor.

The distance between normal LGF and LED should not exceed 0.2mm, as shown below:

C: As structure below, part of LGF has covered the LED, which has the worst light emitting effect, because the light cannot reach the light guide film.

D: As structure below, the fitting distance between LED and LGF should not exceed 0.2mm, otherwise there will be a dark area in the side far light area.

E: As photo below, the vertical distance between the LED and the light area of character should be kept at least 4mm, so could ensure that there is no bright spot near the light area.

F: As photo below, the number of LED should be determined according to the size and height of the product, and the luminance of LED should be at least 1000MCD.

G: The choice of LED location, according to the keypad style, will be evenly distributed in the center of DOME or light guide membrane (top light) or not distributed in the center (side light). If the LED location is not well selected, the light guide effect will also be affected.

3, The different production process of LGF also greatly affects its light emitting effect. The quality of the production process is the last key factor that affects the light emitting effect of LGF, and the most important is the light emitting dot placement on the light medium material. Light from the LED is scattered from the front of the light guide plate through these micro structured dots.

After read above, we believe you should have a direction for how to solve the problem of poor light guide effect of products, this is the purpose that we write this article, hope it could help you a lot.

Some customers may not use LGF to guide light, even though you should also have an understanding about LGF. If there are products that need to guide light, you can try to use LGF to save cost.

And in the next section, I will introduce the production process of LGF and the testing equipment needed; how different that the light conduction effect of products with LGF and without LGF, etc.

Welcome to contact us if you have any questions about LGF.

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Three different production processes of Light Guide Film

Posted on September 22, 2022 by Love Dome

At present, there are three different light guide dot placement processes in the industry: Printing light guide dot, laser engraving light guide dot and mould hot pressing light guide dot. The production efficiency and light guide effect of LGF made by mould hot pressing process are relatively good. Based on the mould hot pressing process, we independently developed a five-station roller press. The LGF light guide plate made of PC (PC Specification) material with better flexibility has a very good light guide effect. The distinction of different production network process are listing as follows:

ItemHot-pressing processLaser processPrinting process
Working methodA mold is used to hot press the luminescent dot on the surface of LGFThe LGF surface is marked with a laser dotWhite luminescent ink is used to print dots on the surface of the LGF
Samples production timeMold making is required, and the lead time would be a little longerThe lead time is shorterNeed to do dot screen, using screen printing, sample speed is slow
Dot sizeMin 0.05mm/Min 0.15mm
Press key requestSuitable for all keysSuitable for not very transparent keysSuitable for all keys
Adjustment of uniformityThe adjustment is complicated and the mold needs to be re-openedThe adjustment is fast, but unstableAdjustment speed is not fast, need to re-make the screen
Production efficiencyOpen mold for production, faster productionLaser dotting speed is slow, production is slowScreen printing, faster speed

And below are some photos of dot with different process:

Dot-by-laser-process
Dot-by-mould-process
Dot-by-printing-process

Welcome to contact us if you have any questions.

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What differences between PC and TPU of LGF Raw Material?

Posted on September 17, 2022 by Love Dome

Do you know what LGF is made of? One of the most important raw materials of LGF products is the medium material of light transmission, including TPU, PC and PMMA. The light emitting effect of different materials is greatly different, due to their different physical characteristics and thickness. PC (PC-Specification.pdf) is the most commonly used as light medium for light guide film, and its light emitting effect is relatively the best one. TPU is also used as light guide film, but very rarely. This is caused by the differences between PC and TPU as follows:

ItemPC materialTPU material
HardnessAround HR140HR70-80
ColorTransparentTransparent
Price/2-3 times compared with PC
Processing dot modePrinting, molding, rollingPrinting, radium carving
Influence on hand sensation after assembling keysThe click feeling of the key decrease by 5~10%The click feeling of the key decrease by 2~6%
Transmittance>89%78%
Brightnesshigher(better)lower(worse)
Thickness of material0.1mm, 0.125mm, 0.175mm, 0.25mm, 0.38mm, 0.5mm0.1mm, 0.15mm
Resistance to chemical corrosionThe corrosion resistance is worse, but because the light guide film is a built-in component, it doesn’t come into contact with as many chemicals, so this factor is not considered as muchCorrosion resistance is better, so it is more suitable for external parts, external parts contact with chemical reagents will be more, such as watchband
Using impactPC will not have issue of yellowTPU will be became yellow after 2 years used, and it affects brightness and transmittance
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What advantages of LGF (light guide film)?

Posted on September 17, 2022 by Love Dome

When says light, it’s natural to think of lights (LED), so how can we use as few lights (LED) as possible to produce the best light effect?

LGF (light guide film), it has the characteristics of ultra-thin, uniform light, color changes and so on. It is a product that converts the point light source of LED into a surface light source.

The mainly advantages of LGF (light guide film) as following:

1. Good luminous effect, uniform brightness, high light intensity.

2. Light, soft, thin thickness. In the usage of mobile phones, different from the light guide plate takes up a large space.

3. Save LED quantity, save power consumption, save cost.

4. Simple structure, does not affect the overall product design (does not affect the click sound of metal dome) and feel good.

Light-guide-film-dome-array-6
Light-guide-film-dome-array-10
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Happy Moon-cake Day

Posted on September 10, 2022 by Love Dome

Today is the 15th day of August (according to the Lunar Calendar) is the Moon Cake Day, one the most important traditional festival in China (Others are Dragon Boat Festival and Spring Festival). And the official name is Mid-Autumn Festival, because it is happened in the middle of Autumn. Family member will come back from their working city to their hometown, to enjoy happy & warm time with their families, and of course will eat the moon-cake and drink the tea.

In order to thank all employees for their dedicated working and efforts, Best Technology prepared handle-made Mid-Autumn moon cakes to express our best wishes and thanks to our staffs.

All staffs from Best Technology received the delicious Moon cakes and everyone is permeated with warm and harmonious festive atmosphere. As a member of Best Tech, I felt full of happiness when received the cakes.

The moon cake not only represents the Mid-Autumn greetings and blessing to employees, but also shows the loving care from management for us. It not only brought laughter, also brought full of touching and motivation to everyone. I believe that in the future, we will cheer up, make persistent efforts, and create a more brilliant tomorrow for the company!

Best Tech is a big family and everyone is a member of this family that we love and help each other.

Since the establishment of company in 2006, Best Technology always pay highly attention to the healthy & happy life of our staffs, in every traditional festival in China, we will receive different beautiful gifts and best wishes.

Best Tech is a big family and everyone is a member of this family that we love and help each other.

Since the establishment of company in 2006, Best Technology always pay highly attention to the healthy & happy life of our staffs, in every traditional festival in China, we will receive different beautiful gifts and best wishes.

At the same time, all the people in Best Technology wish our customers a merry Mid-Autumn Festival, bliss and happiness, wish you a perfect life just like the round moon in Moon-cake Day!!

Also, Best will close for Moon-cake Day from Sept 10-12th, and resume to office on Sept 13th, if you have any inquiry, please contact us.

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The Quality Inspection of the Metal Dome

Posted on May 24, 2022 by Love Dome

Metal dome is an important part used for membrane switch, micro switch, printed circuit boards and so on. It plays a role of conducting the electricity. Thus, it is essential to ensure the quality of the domes.

Metal Domes

But what should be paid heed to when the IQC department detects the quality of the metal domes? Here are five points.

  • Appearance: to check whether there is dust, oil stain, or spot on it.
  • Burr: it can be checked by using the A4 paper to rub the edge of the dome.
  • Force test: to test the force by force tester, and the normal range of the force is ±30%.
  • Contact resistance test: the contact resistance of the stainless steel metal dome is less than 10 Ohm, while the contact resistance of the metal dome plated with nickel, silver and gold is less than 1 Ohm.
  • Lifetime: to test whether the snap dome is up to the mustard by the lifetime tester.

To sum up, in order to guarantee the quality of the metal dome, it is necessary to pay attention to these five points, including appearance, burr, force test, contact resistance test and lifetime.

So, this is the end of this article. At Best Technology, with more than 15 years of experience, we are fully equipped to handle your metal dome or dome array manufacturing requirements. In case if you have any questions, please feel free to contact us via email at sales@metal-domes.com or call us on +86-755 2909-1601/1602/1603.

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How to Produce the 3M Adhesive Dome Array?

Posted on April 22, 2022 by Love Dome

Namely, 3M adhesive dome array uses the 3M adhesive instead of the common adhesive used in the dome array. 3M adhesive is a little bit thick. Some of them even have the ability of high temperature resistance. So, it should be produced by opening a mold, while cannot be processed by laser. The processing steps are as follows.

The process of manufacturing the 3M adhesive dome array:

  • Cover one side of the double-side non-adhesive PET with the 3M adhesive.
  • Punch the dome holes.
  • Cover with Mylar.
  • Punch the outline.
Single and Double Layer Dome Array

And it is noteworthy that although the material used is 3M adhesive, whose viscosity is better, it is indistinguishable from appearance compared with the dome array using common adhesive on account of its transparent color.

Moreover, the model of 3M adhesive dome array can be customized depending on client’s request. But on account of the difference of the specific type and minimum order quantity, it does not necessarily fit with non-adhesive PET, hence circumstances after cases.

At Best Technology, with more than 15 years of experience, we are fully equipped to handle your metal dome or dome array manufacturing requirements. In case if you have any questions, please feel free to contact us via email at sales@metal-domes.com or call us on +86-755 2909-1601/1602/1603.

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The Structure of the Metal Dome Array

Posted on March 31, 2022 by Love Dome

Metal dome array, generally, is double layer structure, but there is also single-layered.

For the double layer dome array, there are two layers, including Mylar, spacer and metal dome. The uppermost is the Mylar with the thickness of 0.05 mm, which is very thin. Then the thickness of the spacer is 0.075 mm with the tolerance of ±0.01 mm. And the underneath is the metal dome.

For this structure, the metal domes are connected by ventilation slots in the fabricated dome array. In this way, when you press the metal dome to conduct, the air can run along the ventilation slots. The purpose of it is to have a good click feeling and conduction ability.

Structure of Double Layer Dome Array

For the single layer dome array, the uppermost is Mylar. And its thickness is generally 0.05 mm or 0.075 mm. Besides, some of the Mylars in the single layer dome array will not have the ventilation slots, while some will make a small hole on it according to the customer’s requirements.

Structure of Single Layer Dome Array

Either the single layer dome array or the double layer dome array, there are release paper and protective film under the metal dome, aiming to protect the dome array. When the dome array has been torn down, the release paper and protective film will be the waste.

Therefore, the effect caused by the specifications of the release paper and protective film is not particularly large.

So, this is all about the introduction to the structure of the dome array. And if you have any questions about the dome or the dome array, you are welcome to contact us.

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What are the Main Applications of Different Metal Domes?

Posted on February 25, 2022 by Love Dome

We all know that there are four types of tactile metal domes, including four-leg, circle, triangle and oblong. And these domes play different roles in various fields, even some of them can be substitute for each other. However, they virtually have their main application fields, which is more or less an unwritten rule.

Metal Domes

Four-leg Metal Dome

In terms of structure, the height of four-leg domes is often higher than that of three other domes, hence the click feeling is also better. And four-leg domes are now mainly concentrated on the relatively large ones ranging from 5 mm to 20 mm, which is one of its advantages. With greater click feeling and longer life, this kind of snap dome is also called membrane switch dome, for which is most commonly used in membrane switch.

Four-leg Dome Sheet

Circle Metal Dome

Contrary to four-leg snap dome, circle metal dome, or round dome, focuses on the relatively small ones like 2.5 mm-5 mm. Thus, when there is only a small space on the PCB, the circle snap dome is the best option. And because most of the domes used in the phone are round dome, it is also named mobile phone dome.

Round Domes on FPC

Triangle Metal Dome

The advantage of triangle snap dome is that it can get the maximum force under the same diameter in comparison with other domes, which means it needs to be pressed hard to be conductive, so as to avoid misoperation especially in industrial control. Therefore, triangle dome metal is extremely suitable for industrial controls, like control panel.

Triangle Domes on PCB

Oblong Metal Dome

Oblong dome is seldom used. Because of its shape, oblong dome metal, also called rectangle snap dome, can be used in a long and narrow space compared with other three domes. And it is mainly used to be mounted on printed circuit boards, and other products such as membranes, panels, and so forth.

Plunger Dome Array

In a word, although it is not stipulated that only one of these snap domes can be used in a field, which indicates that they may be alternatives for each other in accordance with the specific uses and requirements, they generally still have their main application fields. And we, Best Technology, are an experienced electronic company so that if you would like to know more about metal domes or snap domes, you are welcome to contact us.

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How to assemble metal dome on PET adhesive sheet?

Posted on November 20, 2021 by Love Dome

Normally we have three method to assemble metal dome on PET adhesive sheet. Please check details below:

  1. Assembly jig: this is the assembly method we use often currently. According to the drawing of PET adhesive sheet (dome array) to make a fixture, material is aluminum plate. The dome holes on plate is base on shape of different metal domes and qty. Like below photos, place with 8.4mm four legs metal dome with qty 69 keys.
Assembly jig (plate)
Place PET adhesive (dome array) on assembly Jig (plate)
Stick metal dome on PET adhesive
  • Through the assembly of tube fixture, this method has small tolerance and fast speed, but the cost is relatively high, suitable for relatively large quantity of production. Like below photos.
Collect metal domes in tube
Dome switch Tube in assembly machine
  • Place snap dome or metal dome on PET adhesive by manual. Usually if the customer only requires few prototype and samples, and does not want to pay the fixture fee, we will manually place metal domes of the sample. The disadvantage of this fitting method is that the fitting tolerance is relatively large, and some may tilt more severely.
Place metal dome on PET adhesive by manual

This video you will know more clearly.

If you still have any question after read, please feel free to contact us, we are here always and would solve your issue and provide our help to you.

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