Working principles of a resistive touch screen and a capacitive touch screen

resistive touch screen and capacitive touch screenResistive screens and capacitive screens are the two main kinds of mobile screens on the market today. Generally speaking, resistive screen phones can be operated with a finger or a stylus; while capacitive screen phones can only be operated with fingers and cannot be operated with ordinary stylus, but we can use a dedicated capacitive screen stylus to substitute the finger to operate; while the resistive screen phone can be operated with a finger or a stylus. Why do they have such a difference? Is it related to their working principle? Let’s SAM Sputter Targets answer it for you.

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What is the difference between a capacitive screen and a resistive screen?

Mobile phones have become an indispensable part of contemporary society. You may use your mobile phone every day, but you don’t know about it. For example, the screens of a mobile phone are mainly divided into a resistive screen and a capacitive screen, but do you know the difference between these two kinds of screens? If you do not know the answer, let’s SAM Sputter Targets answer it for you.

screen

Simply speaking, capacitive screen phones can only be operated with fingers and cannot be operated with ordinary stylus, but we can use a dedicated capacitive screen stylus to substitute the finger to operate; while  resistive screen phones can be operated with a finger or a stylus. From this point of view, some people may think that the latter has an advantage. However, although the capacitive screen can only be operated with a finger, it can largely protect the screen and reduce false touches. Therefore, the two screens actually have their own advantages. Let’s then take a look at their strengths and weaknesses.

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Manufacturing process of semiconductor wafer

Semiconductor wafers are the basic material for manufacturing chips. The most important raw material for semiconductor integrated circuits is silicon, which is widely found in rocks and gravel in the form of silicate or silicon dioxide in nature. The manufacturing process of semiconductor wafers/silicon wafers can be divided into three basic steps: silicon purification, monocrystalline silicon growth, and wafer formation.

Silicon purification

The sandstone material is placed in a 2000 °C electric arc furnace which has a carbon source. At high temperatures, the silica in the carbon and in the sandstone undergoes a chemical reaction (carbon is combined with oxygen, leaving silicon) to obtain pure silicon having a purity of about 98%, also known as metallurgical grade silicon. Continue reading “Manufacturing process of semiconductor wafer”

Differences between vacuum evaporation and sputter coating

It is well known that vacuum coating has two common methods: vacuum evaporation and sputter coating. However, many people have doubts about the difference between evaporation and sputter coating. Let SAM Sputter Targets answer it for you.

sputter coating3First, let’s take a look at the definition of these two words. The vacuum evaporation is carried out by means of resistance heating, electron beam or laser bombardment in an environment with a vacuum of not less than 10-2 Pa, and the evaporation material is heated to a certain temperature to evaporate or sublimate a large number of molecules or atoms, and then directly deposited on a substrate to form a film. Continue reading “Differences between vacuum evaporation and sputter coating”

What is Extreme High Speed Laser Material Deposition(EHLA)?

The German research institute Fraunhofer Institute for Laser Technology has developed a new metal part coating process called Extreme High Speed Laser Material Deposition (EHLA).

The coating is processed by a laser to form a molten pool with a small amount of powder added. The metal powder is then deposited by laser beam and movement between the components to form a thin, uniform coating. What makes EHLA different from other deposition processes is that the powder melts completely before it is applied to the surface of the part. This process can effectively reduce resource consumption by introducing approximately 90% of the material into the correct area, while other processes can only achieve 50%.

Extreme High Speed Laser Material Deposition

But the most outstanding part of the process is its amazing speed. With the EHLA process, coating processing can be performed at a speed 100 to 250 times higher than conventional laser material deposition speeds. Moreover, it has almost no heat during processing and can be used for heat-sensitive component coating processing. In addition, it is also possible to perform tandem coating processing. In the future, it will be possible for products to be protected from wear and tear during their life cycle.

Researchers say the new process protects metal parts from corrosion and wear without the need to deposit chromium that pollutes the environment. EHLA is environmentally friendly because it does not use chemicals. In addition, the coating adheres to the substrate in a material-locking manner to prevent peeling. And the process is also compatible with other coatings such as iron, nickel and cobalt based alloys. With these advantages, EHLA presents a promising application prospect.

Stanford Advanced Materials (SAM) Corporation is a global supplier of various sputtering targets such as metals, alloys, oxides, ceramic materials. If you are interested, please visit our website https://www.sputtertargets.net/ for more information.

Five evaporation sources for heating

The evaporation source is a heating element used to vaporize and vaporize the molding material. The evaporation sources currently used mainly include the following types:

Resistance evaporation heating source

The resistance heating method is simple and easy to operate, and is a common application method: a filament-like or sheet-like high melting point metal (such as Tungsten, Molybdenum, Titanium, etc.) is made into an evaporation source of a suitable shape. It is equipped with an evaporation material to turn on the power supply, and the evaporation material is directly heated and evaporated. The resistance heating method should mainly consider two problems, the melting point and vapor pressure of the evaporation material; the reaction of the evaporation material with the coating material and the wettability caused by the coating material.

Electron beam evaporation source

The evaporation material is placed in a water-cooled copper dry pot and directly heated by an electron beam, which is called electron beam heating. It can vaporize the evaporation material and form a film on the surface of the substrate. It is an important heating method and development direction in the vacuum evaporation coating technology. In the resistance heating method, the coating material and the evaporation material are in direct contact, and the temperature of the evaporation material is higher than that of the coating material, and is easily mixed into the coating material, especially in the semiconductor device coating. Electron beam evaporation can overcome many shortcomings of general resistance heating evaporation, and is particularly suitable for preparing high melting point film materials and high purity film materials.

High frequency induction heating evaporation source

The high-frequency induction heating evaporation source places the graphite or quartz crucible containing the evaporation material in the center of the water-cooled high-frequency spiral coil, so that the evaporation material generates strong eddy current loss and hysteresis loss under the induction of the magnetic field in the high frequency band (to Ferromagnetic), causing the evaporating material to heat up until evaporation. The smaller the volume of the evaporated material is, the higher the frequency of induction is. In the large-scale vacuum aluminum plating equipment on the steel strip, the high-frequency induction heating evaporation process has achieved great success.

Radiant heating evaporation source

For materials with high absorption of infrared radiation, it can be evaporated by radiant heating, and many substances are evaporated by this method. In addition, the reflectivity of the metal for infrared radiation is high, and the absorption rate of quartz for infrared radiation is low, so they are difficult to be evaporated by radiation heating. The main advantage of the radiant heating method is that the evaporation is only heated on the surface, and the adsorbed gas is released on the surface without splashing the material.

Laser beam evaporation source

The evaporation technique using a laser beam evaporation source is an ideal film preparation method because the laser can be installed outside the vacuum chamber. This not only simplifies the space arrangement inside the vacuum chamber and reduces the abandonment of the heating source, but also completely avoids the contamination of the evaporation material by the evaporator, thus it is advantageous for obtaining a high-purity film.

 

Stanford Advanced Materials (SAM) Corporation is a global supplier of various sputtering targets such as metals, alloys, oxides, ceramic materials. If you are interested, please visit our website https://www.sputtertargets.net/ for more information.

Lithium Battery Technology-An Overview

What is a lithium battery?

Literally speaking, some people may think that lithium batteries are only made of metallic lithium. In fact, lithium battery is a relatively broad concept, which can be roughly divided into two categories: lithium metal batteries and lithium ion batteries. Lithium batteries generally refer to batteries using a lithium metal or a lithium alloy as a negative electrode and utilize a non-aqueous electrolyte. For example, in renewable energy applications, the main chemical of lithium batteries is lithium iron phosphate (LiFePO4), which has good safety, good thermal stability, high rated current and long cycle life.

Lithium battery2

Advantages

Compared with traditional batteries such as lead acid, nickel chrome and nickel hydrogen, lithium batteries do not produce harmful heavy metal elements such as lead, mercury and cadmium. Their electrolytes are organic solvents and lithium salts, most of which are non-toxic or low-toxic. Therefore, the pollution is relatively slight. There is also no risk of exposure to corrosive electrolytes such as sulfuric acid or potassium hydroxide. In most cases, lithium batteries do not present an explosion hazard even when stored in confined areas, and their well-designed systems do not require active cooling or ventilation. In addition, lithium batteries have an extremely long cycle life, and some manufacturers can even guarantee a battery life of up to 10,000 times. In general, lithium batteries are a perfect energy storage solution.

Application

With the development of microelectronics technology in the twentieth century, the number of miniaturized devices is increasing, and high requirements are placed on the power supplies. Lithium batteries have entered a large-scale practical stage. The earliest is the primary lithium battery used in cardiac pacemakers. The kind of battery has a very low self-discharge rate, and the discharge voltage is very gentle, making the pacemaker expected to be implanted in the human body for a long time. Lithium-manganese batteries generally have a nominal voltage higher than 3.0 volts, and are more suitable for using as integrated circuit power supplies, which are widely used in computers, calculators, and watches. Lithium-ion batteries are widely used in mobile phones, notebook computers, power tools, electric vehicles, street lamp backup power supplies, navigation lights, and small household appliances.

Stanford Advanced Materials (SAM) Corporation is a global supplier of various sputtering targets such as metals, alloys, oxides, ceramic materials. We provide high purity of Lithium pure metal as well as sputtering targets and evaporation materials, please visit our website https://www.sputtertargets.net for more information.

Advantages and Disadvantages of Pulsed laser deposition (PLD)

Pulsed laser deposition is one of the methods of thin film preparation, and several others include chemical vapor deposition, material sputtering, and etc. Pulsed Laser Deposition (PLD), also known as Pulsed Laser Ablation (PLA), uses a laser to bombard the surface of the target, raising its surface temperature and further producing high temperature and high pressure plasma ( T>104K), depositing on different substrates to form a film.

Advantages

1 It is easy to obtain multi- component film that is of the desired stoichiometric ratio by PLD.

2 It has high deposition rate, short test period and low substrate temperature requirements. Films prepared by PLD are uniform.

3 The process is simple and flexible with great development potential and great compatibility.

4 Process parameters can be arbitrarily adjusted, and there is no limit to the type of PLD targets. Multi-target components are flexible, and it is easy to prepare multilayer films and heterojunctions.

5 It is easy to clean and can prepare a variety of thin film materials.

6 PLD uses UV pulsed laser of high photon capability and high energy density as the energy source for plasma generation, so it is non-polluting and easy to control.

 Pulsed laser deposition

Disadvantages

1 For quite a number of materials, there are molten small particles or target fragments in the deposited film, which are sputtered during the laser-induced explosion. The presence of these particles greatly reduces the quality of the film.

2 The feasibility of laser method for large area deposition has not been proved yet.

3 Average deposition rate of PLD is slow.

4 In view of the cost and deposition scale of laser film preparation equipment, it seems that PLD is only suitable for the development of high-tech fields such as microelectronics, sensor technology, optical technology and new material films.

 

Stanford Advanced Materials (SAM) Corporation is a global supplier of various sputtering targets such as metals, alloys, oxides, ceramic materials. Please visit our website https://www.sputtertargets.net for more information.